--- linux-2.4.26-rc1/drivers/md/dm-daemon.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-daemon.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#include "dm.h"
+#include "dm-daemon.h"
+
+#include <linux/module.h>
+#include <linux/sched.h>
+
+static int daemon(void *arg)
+{
+ struct dm_daemon *dd = (struct dm_daemon *) arg;
+ DECLARE_WAITQUEUE(wq, current);
+
+ daemonize();
+ reparent_to_init();
+
+ /* block all signals */
+ spin_lock_irq(¤t->sigmask_lock);
+ sigfillset(¤t->blocked);
+ flush_signals(current);
+ spin_unlock_irq(¤t->sigmask_lock);
+
+ strcpy(current->comm, dd->name);
+ atomic_set(&dd->please_die, 0);
+
+ add_wait_queue(&dd->job_queue, &wq);
+
+ down(&dd->run_lock);
+ up(&dd->start_lock);
+
+ /*
+ * dd->fn() could do anything, very likely it will
+ * suspend. So we can't set the state to
+ * TASK_INTERRUPTIBLE before calling it. In order to
+ * prevent a race with a waking thread we do this little
+ * dance with the dd->woken variable.
+ */
+ while (1) {
+ do {
+ set_current_state(TASK_RUNNING);
+
+ if (atomic_read(&dd->please_die))
+ goto out;
+
+ atomic_set(&dd->woken, 0);
+ dd->fn();
+ yield();
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ } while (atomic_read(&dd->woken));
+
+ schedule();
+ }
+
+ out:
+ remove_wait_queue(&dd->job_queue, &wq);
+ up(&dd->run_lock);
+ return 0;
+}
+
+int dm_daemon_start(struct dm_daemon *dd, const char *name, void (*fn)(void))
+{
+ pid_t pid = 0;
+
+ /*
+ * Initialise the dm_daemon.
+ */
+ dd->fn = fn;
+ strncpy(dd->name, name, sizeof(dd->name) - 1);
+ sema_init(&dd->start_lock, 1);
+ sema_init(&dd->run_lock, 1);
+ init_waitqueue_head(&dd->job_queue);
+
+ /*
+ * Start the new thread.
+ */
+ down(&dd->start_lock);
+ pid = kernel_thread(daemon, dd, 0);
+ if (pid <= 0) {
+ DMERR("Failed to start %s thread", name);
+ return -EAGAIN;
+ }
+
+ /*
+ * wait for the daemon to up this mutex.
+ */
+ down(&dd->start_lock);
+ up(&dd->start_lock);
+
+ return 0;
+}
+
+void dm_daemon_stop(struct dm_daemon *dd)
+{
+ atomic_set(&dd->please_die, 1);
+ dm_daemon_wake(dd);
+ down(&dd->run_lock);
+ up(&dd->run_lock);
+}
+
+void dm_daemon_wake(struct dm_daemon *dd)
+{
+ atomic_set(&dd->woken, 1);
+ wake_up_interruptible(&dd->job_queue);
+}
+
+EXPORT_SYMBOL(dm_daemon_start);
+EXPORT_SYMBOL(dm_daemon_stop);
+EXPORT_SYMBOL(dm_daemon_wake);
--- linux-2.4.26-rc1/drivers/md/dm-daemon.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-daemon.h Wed Mar 31 13:48:32 2004
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef DM_DAEMON_H
+#define DM_DAEMON_H
+
+#include <asm/atomic.h>
+#include <asm/semaphore.h>
+
+struct dm_daemon {
+ void (*fn)(void);
+ char name[16];
+ atomic_t please_die;
+ struct semaphore start_lock;
+ struct semaphore run_lock;
+
+ atomic_t woken;
+ wait_queue_head_t job_queue;
+};
+
+int dm_daemon_start(struct dm_daemon *dd, const char *name, void (*fn)(void));
+void dm_daemon_stop(struct dm_daemon *dd);
+void dm_daemon_wake(struct dm_daemon *dd);
+int dm_daemon_running(struct dm_daemon *dd);
+
+#endif
--- linux-2.4.26-rc1/drivers/md/dm-exception-store.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-exception-store.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,673 @@
+/*
+ * dm-snapshot.c
+ *
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-snapshot.h"
+#include "dm-io.h"
+#include "kcopyd.h"
+
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+/*-----------------------------------------------------------------
+ * Persistent snapshots, by persistent we mean that the snapshot
+ * will survive a reboot.
+ *---------------------------------------------------------------*/
+
+/*
+ * We need to store a record of which parts of the origin have
+ * been copied to the snapshot device. The snapshot code
+ * requires that we copy exception chunks to chunk aligned areas
+ * of the COW store. It makes sense therefore, to store the
+ * metadata in chunk size blocks.
+ *
+ * There is no backward or forward compatibility implemented,
+ * snapshots with different disk versions than the kernel will
+ * not be usable. It is expected that "lvcreate" will blank out
+ * the start of a fresh COW device before calling the snapshot
+ * constructor.
+ *
+ * The first chunk of the COW device just contains the header.
+ * After this there is a chunk filled with exception metadata,
+ * followed by as many exception chunks as can fit in the
+ * metadata areas.
+ *
+ * All on disk structures are in little-endian format. The end
+ * of the exceptions info is indicated by an exception with a
+ * new_chunk of 0, which is invalid since it would point to the
+ * header chunk.
+ */
+
+/*
+ * Magic for persistent snapshots: "SnAp" - Feeble isn't it.
+ */
+#define SNAP_MAGIC 0x70416e53
+
+/*
+ * The on-disk version of the metadata.
+ */
+#define SNAPSHOT_DISK_VERSION 1
+
+struct disk_header {
+ uint32_t magic;
+
+ /*
+ * Is this snapshot valid. There is no way of recovering
+ * an invalid snapshot.
+ */
+ uint32_t valid;
+
+ /*
+ * Simple, incrementing version. no backward
+ * compatibility.
+ */
+ uint32_t version;
+
+ /* In sectors */
+ uint32_t chunk_size;
+};
+
+struct disk_exception {
+ uint64_t old_chunk;
+ uint64_t new_chunk;
+};
+
+struct commit_callback {
+ void (*callback)(void *, int success);
+ void *context;
+};
+
+/*
+ * The top level structure for a persistent exception store.
+ */
+struct pstore {
+ struct dm_snapshot *snap; /* up pointer to my snapshot */
+ int version;
+ int valid;
+ uint32_t chunk_size;
+ uint32_t exceptions_per_area;
+
+ /*
+ * Now that we have an asynchronous kcopyd there is no
+ * need for large chunk sizes, so it wont hurt to have a
+ * whole chunks worth of metadata in memory at once.
+ */
+ void *area;
+
+ /*
+ * Used to keep track of which metadata area the data in
+ * 'chunk' refers to.
+ */
+ uint32_t current_area;
+
+ /*
+ * The next free chunk for an exception.
+ */
+ uint32_t next_free;
+
+ /*
+ * The index of next free exception in the current
+ * metadata area.
+ */
+ uint32_t current_committed;
+
+ atomic_t pending_count;
+ uint32_t callback_count;
+ struct commit_callback *callbacks;
+};
+
+static inline unsigned int sectors_to_pages(unsigned int sectors)
+{
+ return sectors / (PAGE_SIZE / SECTOR_SIZE);
+}
+
+static int alloc_area(struct pstore *ps)
+{
+ int r = -ENOMEM;
+ size_t i, len, nr_pages;
+ struct page *page, *last = NULL;
+
+ len = ps->chunk_size << SECTOR_SHIFT;
+
+ /*
+ * Allocate the chunk_size block of memory that will hold
+ * a single metadata area.
+ */
+ ps->area = vmalloc(len);
+ if (!ps->area)
+ return r;
+
+ nr_pages = sectors_to_pages(ps->chunk_size);
+
+ /*
+ * We lock the pages for ps->area into memory since
+ * they'll be doing a lot of io. We also chain them
+ * together ready for dm-io.
+ */
+ for (i = 0; i < nr_pages; i++) {
+ page = vmalloc_to_page(ps->area + (i * PAGE_SIZE));
+ LockPage(page);
+ if (last)
+ last->list.next = &page->list;
+ last = page;
+ }
+
+ return 0;
+}
+
+static void free_area(struct pstore *ps)
+{
+ size_t i, nr_pages;
+ struct page *page;
+
+ nr_pages = sectors_to_pages(ps->chunk_size);
+ for (i = 0; i < nr_pages; i++) {
+ page = vmalloc_to_page(ps->area + (i * PAGE_SIZE));
+ page->list.next = NULL;
+ UnlockPage(page);
+ }
+
+ vfree(ps->area);
+}
+
+/*
+ * Read or write a chunk aligned and sized block of data from a device.
+ */
+static int chunk_io(struct pstore *ps, uint32_t chunk, int rw)
+{
+ struct io_region where;
+ unsigned int bits;
+
+ where.dev = ps->snap->cow->dev;
+ where.sector = ps->chunk_size * chunk;
+ where.count = ps->chunk_size;
+
+ return dm_io_sync(1, &where, rw, vmalloc_to_page(ps->area), 0, &bits);
+}
+
+/*
+ * Read or write a metadata area. Remembering to skip the first
+ * chunk which holds the header.
+ */
+static int area_io(struct pstore *ps, uint32_t area, int rw)
+{
+ int r;
+ uint32_t chunk;
+
+ /* convert a metadata area index to a chunk index */
+ chunk = 1 + ((ps->exceptions_per_area + 1) * area);
+
+ r = chunk_io(ps, chunk, rw);
+ if (r)
+ return r;
+
+ ps->current_area = area;
+ return 0;
+}
+
+static int zero_area(struct pstore *ps, uint32_t area)
+{
+ memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+ return area_io(ps, area, WRITE);
+}
+
+static int read_header(struct pstore *ps, int *new_snapshot)
+{
+ int r;
+ struct disk_header *dh;
+
+ r = chunk_io(ps, 0, READ);
+ if (r)
+ return r;
+
+ dh = (struct disk_header *) ps->area;
+
+ if (le32_to_cpu(dh->magic) == 0) {
+ *new_snapshot = 1;
+
+ } else if (le32_to_cpu(dh->magic) == SNAP_MAGIC) {
+ *new_snapshot = 0;
+ ps->valid = le32_to_cpu(dh->valid);
+ ps->version = le32_to_cpu(dh->version);
+ ps->chunk_size = le32_to_cpu(dh->chunk_size);
+
+ } else {
+ DMWARN("Invalid/corrupt snapshot");
+ r = -ENXIO;
+ }
+
+ return r;
+}
+
+static int write_header(struct pstore *ps)
+{
+ struct disk_header *dh;
+
+ memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+
+ dh = (struct disk_header *) ps->area;
+ dh->magic = cpu_to_le32(SNAP_MAGIC);
+ dh->valid = cpu_to_le32(ps->valid);
+ dh->version = cpu_to_le32(ps->version);
+ dh->chunk_size = cpu_to_le32(ps->chunk_size);
+
+ return chunk_io(ps, 0, WRITE);
+}
+
+/*
+ * Access functions for the disk exceptions, these do the endian conversions.
+ */
+static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
+{
+ if (index >= ps->exceptions_per_area)
+ return NULL;
+
+ return ((struct disk_exception *) ps->area) + index;
+}
+
+static int read_exception(struct pstore *ps,
+ uint32_t index, struct disk_exception *result)
+{
+ struct disk_exception *e;
+
+ e = get_exception(ps, index);
+ if (!e)
+ return -EINVAL;
+
+ /* copy it */
+ result->old_chunk = le64_to_cpu(e->old_chunk);
+ result->new_chunk = le64_to_cpu(e->new_chunk);
+
+ return 0;
+}
+
+static int write_exception(struct pstore *ps,
+ uint32_t index, struct disk_exception *de)
+{
+ struct disk_exception *e;
+
+ e = get_exception(ps, index);
+ if (!e)
+ return -EINVAL;
+
+ /* copy it */
+ e->old_chunk = cpu_to_le64(de->old_chunk);
+ e->new_chunk = cpu_to_le64(de->new_chunk);
+
+ return 0;
+}
+
+/*
+ * Registers the exceptions that are present in the current area.
+ * 'full' is filled in to indicate if the area has been
+ * filled.
+ */
+static int insert_exceptions(struct pstore *ps, int *full)
+{
+ int r;
+ unsigned int i;
+ struct disk_exception de;
+
+ /* presume the area is full */
+ *full = 1;
+
+ for (i = 0; i < ps->exceptions_per_area; i++) {
+ r = read_exception(ps, i, &de);
+
+ if (r)
+ return r;
+
+ /*
+ * If the new_chunk is pointing at the start of
+ * the COW device, where the first metadata area
+ * is we know that we've hit the end of the
+ * exceptions. Therefore the area is not full.
+ */
+ if (de.new_chunk == 0LL) {
+ ps->current_committed = i;
+ *full = 0;
+ break;
+ }
+
+ /*
+ * Keep track of the start of the free chunks.
+ */
+ if (ps->next_free <= de.new_chunk)
+ ps->next_free = de.new_chunk + 1;
+
+ /*
+ * Otherwise we add the exception to the snapshot.
+ */
+ r = dm_add_exception(ps->snap, de.old_chunk, de.new_chunk);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int read_exceptions(struct pstore *ps)
+{
+ uint32_t area;
+ int r, full = 1;
+
+ /*
+ * Keeping reading chunks and inserting exceptions until
+ * we find a partially full area.
+ */
+ for (area = 0; full; area++) {
+ r = area_io(ps, area, READ);
+ if (r)
+ return r;
+
+ r = insert_exceptions(ps, &full);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static inline struct pstore *get_info(struct exception_store *store)
+{
+ return (struct pstore *) store->context;
+}
+
+static void persistent_fraction_full(struct exception_store *store,
+ sector_t *numerator, sector_t *denominator)
+{
+ *numerator = get_info(store)->next_free * store->snap->chunk_size;
+ *denominator = get_dev_size(store->snap->cow->dev);
+}
+
+static void persistent_destroy(struct exception_store *store)
+{
+ struct pstore *ps = get_info(store);
+
+ dm_io_put(sectors_to_pages(ps->chunk_size));
+ vfree(ps->callbacks);
+ free_area(ps);
+ kfree(ps);
+}
+
+static int persistent_read_metadata(struct exception_store *store)
+{
+ int r, new_snapshot;
+ struct pstore *ps = get_info(store);
+
+ /*
+ * Read the snapshot header.
+ */
+ r = read_header(ps, &new_snapshot);
+ if (r)
+ return r;
+
+ /*
+ * Do we need to setup a new snapshot ?
+ */
+ if (new_snapshot) {
+ r = write_header(ps);
+ if (r) {
+ DMWARN("write_header failed");
+ return r;
+ }
+
+ r = zero_area(ps, 0);
+ if (r) {
+ DMWARN("zero_area(0) failed");
+ return r;
+ }
+
+ } else {
+ /*
+ * Sanity checks.
+ */
+ if (!ps->valid) {
+ DMWARN("snapshot is marked invalid");
+ return -EINVAL;
+ }
+
+ if (ps->version != SNAPSHOT_DISK_VERSION) {
+ DMWARN("unable to handle snapshot disk version %d",
+ ps->version);
+ return -EINVAL;
+ }
+
+ /*
+ * Read the metadata.
+ */
+ r = read_exceptions(ps);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int persistent_prepare(struct exception_store *store,
+ struct exception *e)
+{
+ struct pstore *ps = get_info(store);
+ uint32_t stride;
+ sector_t size = get_dev_size(store->snap->cow->dev);
+
+ /* Is there enough room ? */
+ if (size < ((ps->next_free + 1) * store->snap->chunk_size))
+ return -ENOSPC;
+
+ e->new_chunk = ps->next_free;
+
+ /*
+ * Move onto the next free pending, making sure to take
+ * into account the location of the metadata chunks.
+ */
+ stride = (ps->exceptions_per_area + 1);
+ if ((++ps->next_free % stride) == 1)
+ ps->next_free++;
+
+ atomic_inc(&ps->pending_count);
+ return 0;
+}
+
+static void persistent_commit(struct exception_store *store,
+ struct exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
+{
+ int r;
+ unsigned int i;
+ struct pstore *ps = get_info(store);
+ struct disk_exception de;
+ struct commit_callback *cb;
+
+ de.old_chunk = e->old_chunk;
+ de.new_chunk = e->new_chunk;
+ write_exception(ps, ps->current_committed++, &de);
+
+ /*
+ * Add the callback to the back of the array. This code
+ * is the only place where the callback array is
+ * manipulated, and we know that it will never be called
+ * multiple times concurrently.
+ */
+ cb = ps->callbacks + ps->callback_count++;
+ cb->callback = callback;
+ cb->context = callback_context;
+
+ /*
+ * If there are no more exceptions in flight, or we have
+ * filled this metadata area we commit the exceptions to
+ * disk.
+ */
+ if (atomic_dec_and_test(&ps->pending_count) ||
+ (ps->current_committed == ps->exceptions_per_area)) {
+ r = area_io(ps, ps->current_area, WRITE);
+ if (r)
+ ps->valid = 0;
+
+ for (i = 0; i < ps->callback_count; i++) {
+ cb = ps->callbacks + i;
+ cb->callback(cb->context, r == 0 ? 1 : 0);
+ }
+
+ ps->callback_count = 0;
+ }
+
+ /*
+ * Have we completely filled the current area ?
+ */
+ if (ps->current_committed == ps->exceptions_per_area) {
+ ps->current_committed = 0;
+ r = zero_area(ps, ps->current_area + 1);
+ if (r)
+ ps->valid = 0;
+ }
+}
+
+static void persistent_drop(struct exception_store *store)
+{
+ struct pstore *ps = get_info(store);
+
+ ps->valid = 0;
+ if (write_header(ps))
+ DMWARN("write header failed");
+}
+
+int dm_create_persistent(struct exception_store *store, uint32_t chunk_size)
+{
+ int r;
+ struct pstore *ps;
+
+ r = dm_io_get(sectors_to_pages(chunk_size));
+ if (r)
+ return r;
+
+ /* allocate the pstore */
+ ps = kmalloc(sizeof(*ps), GFP_KERNEL);
+ if (!ps) {
+ r = -ENOMEM;
+ goto bad;
+ }
+
+ ps->snap = store->snap;
+ ps->valid = 1;
+ ps->version = SNAPSHOT_DISK_VERSION;
+ ps->chunk_size = chunk_size;
+ ps->exceptions_per_area = (chunk_size << SECTOR_SHIFT) /
+ sizeof(struct disk_exception);
+ ps->next_free = 2; /* skipping the header and first area */
+ ps->current_committed = 0;
+
+ r = alloc_area(ps);
+ if (r)
+ goto bad;
+
+ /*
+ * Allocate space for all the callbacks.
+ */
+ ps->callback_count = 0;
+ atomic_set(&ps->pending_count, 0);
+ ps->callbacks = vcalloc(ps->exceptions_per_area,
+ sizeof(*ps->callbacks));
+
+ if (!ps->callbacks) {
+ r = -ENOMEM;
+ goto bad;
+ }
+
+ store->destroy = persistent_destroy;
+ store->read_metadata = persistent_read_metadata;
+ store->prepare_exception = persistent_prepare;
+ store->commit_exception = persistent_commit;
+ store->drop_snapshot = persistent_drop;
+ store->fraction_full = persistent_fraction_full;
+ store->context = ps;
+
+ return 0;
+
+ bad:
+ dm_io_put(sectors_to_pages(chunk_size));
+ if (ps) {
+ if (ps->callbacks)
+ vfree(ps->callbacks);
+
+ kfree(ps);
+ }
+ return r;
+}
+
+/*-----------------------------------------------------------------
+ * Implementation of the store for non-persistent snapshots.
+ *---------------------------------------------------------------*/
+struct transient_c {
+ sector_t next_free;
+};
+
+void transient_destroy(struct exception_store *store)
+{
+ kfree(store->context);
+}
+
+int transient_read_metadata(struct exception_store *store)
+{
+ return 0;
+}
+
+int transient_prepare(struct exception_store *store, struct exception *e)
+{
+ struct transient_c *tc = (struct transient_c *) store->context;
+ sector_t size = get_dev_size(store->snap->cow->dev);
+
+ if (size < (tc->next_free + store->snap->chunk_size))
+ return -1;
+
+ e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
+ tc->next_free += store->snap->chunk_size;
+
+ return 0;
+}
+
+void transient_commit(struct exception_store *store,
+ struct exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
+{
+ /* Just succeed */
+ callback(callback_context, 1);
+}
+
+static void transient_fraction_full(struct exception_store *store,
+ sector_t *numerator, sector_t *denominator)
+{
+ *numerator = ((struct transient_c *) store->context)->next_free;
+ *denominator = get_dev_size(store->snap->cow->dev);
+}
+
+int dm_create_transient(struct exception_store *store,
+ struct dm_snapshot *s, int blocksize)
+{
+ struct transient_c *tc;
+
+ memset(store, 0, sizeof(*store));
+ store->destroy = transient_destroy;
+ store->read_metadata = transient_read_metadata;
+ store->prepare_exception = transient_prepare;
+ store->commit_exception = transient_commit;
+ store->fraction_full = transient_fraction_full;
+ store->snap = s;
+
+ tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
+ if (!tc)
+ return -ENOMEM;
+
+ tc->next_free = 0;
+ store->context = tc;
+
+ return 0;
+}
--- linux-2.4.26-rc1/drivers/md/dm-io.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-io.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,361 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-io.h"
+
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/bitops.h>
+
+/* FIXME: can we shrink this ? */
+struct io_context {
+ int rw;
+ unsigned int error;
+ atomic_t count;
+ struct task_struct *sleeper;
+ io_notify_fn callback;
+ void *context;
+};
+
+/*
+ * We maintain a pool of buffer heads for dispatching the io.
+ */
+static unsigned int _num_bhs;
+static mempool_t *_buffer_pool;
+
+/*
+ * io contexts are only dynamically allocated for asynchronous
+ * io. Since async io is likely to be the majority of io we'll
+ * have the same number of io contexts as buffer heads ! (FIXME:
+ * must reduce this).
+ */
+mempool_t *_io_pool;
+
+static void *alloc_bh(int gfp_mask, void *pool_data)
+{
+ struct buffer_head *bh;
+
+ bh = kmem_cache_alloc(bh_cachep, gfp_mask);
+ if (bh) {
+ bh->b_reqnext = NULL;
+ init_waitqueue_head(&bh->b_wait);
+ INIT_LIST_HEAD(&bh->b_inode_buffers);
+ }
+
+ return bh;
+}
+
+static void *alloc_io(int gfp_mask, void *pool_data)
+{
+ return kmalloc(sizeof(struct io_context), gfp_mask);
+}
+
+static void free_io(void *element, void *pool_data)
+{
+ kfree(element);
+}
+
+static unsigned int pages_to_buffers(unsigned int pages)
+{
+ return 4 * pages; /* too many ? */
+}
+
+static int resize_pool(unsigned int new_bhs)
+{
+ int r = 0;
+
+ if (_buffer_pool) {
+ if (new_bhs == 0) {
+ /* free off the pools */
+ mempool_destroy(_buffer_pool);
+ mempool_destroy(_io_pool);
+ _buffer_pool = _io_pool = NULL;
+ } else {
+ /* resize the pools */
+ r = mempool_resize(_buffer_pool, new_bhs, GFP_KERNEL);
+ if (!r)
+ r = mempool_resize(_io_pool,
+ new_bhs, GFP_KERNEL);
+ }
+ } else {
+ /* create new pools */
+ _buffer_pool = mempool_create(new_bhs, alloc_bh,
+ mempool_free_slab, bh_cachep);
+ if (!_buffer_pool)
+ r = -ENOMEM;
+
+ _io_pool = mempool_create(new_bhs, alloc_io, free_io, NULL);
+ if (!_io_pool) {
+ mempool_destroy(_buffer_pool);
+ _buffer_pool = NULL;
+ r = -ENOMEM;
+ }
+ }
+
+ if (!r)
+ _num_bhs = new_bhs;
+
+ return r;
+}
+
+int dm_io_get(unsigned int num_pages)
+{
+ return resize_pool(_num_bhs + pages_to_buffers(num_pages));
+}
+
+void dm_io_put(unsigned int num_pages)
+{
+ resize_pool(_num_bhs - pages_to_buffers(num_pages));
+}
+
+/*-----------------------------------------------------------------
+ * We need to keep track of which region a buffer is doing io
+ * for. In order to save a memory allocation we store this in an
+ * unused field of the buffer head, and provide these access
+ * functions.
+ *
+ * FIXME: add compile time check that an unsigned int can fit
+ * into a pointer.
+ *
+ *---------------------------------------------------------------*/
+static inline void bh_set_region(struct buffer_head *bh, unsigned int region)
+{
+ bh->b_journal_head = (void *) region;
+}
+
+static inline int bh_get_region(struct buffer_head *bh)
+{
+ return (unsigned int) bh->b_journal_head;
+}
+
+/*-----------------------------------------------------------------
+ * We need an io object to keep track of the number of bhs that
+ * have been dispatched for a particular io.
+ *---------------------------------------------------------------*/
+static void dec_count(struct io_context *io, unsigned int region, int error)
+{
+ if (error)
+ set_bit(region, &io->error);
+
+ if (atomic_dec_and_test(&io->count)) {
+ if (io->sleeper)
+ wake_up_process(io->sleeper);
+
+ else {
+ int r = io->error;
+ io_notify_fn fn = io->callback;
+ void *context = io->context;
+
+ mempool_free(io, _io_pool);
+ fn(r, context);
+ }
+ }
+}
+
+static void endio(struct buffer_head *bh, int uptodate)
+{
+ struct io_context *io = (struct io_context *) bh->b_private;
+
+ if (!uptodate && io->rw != WRITE) {
+ /*
+ * We need to zero this region, otherwise people
+ * like kcopyd may write the arbitrary contents
+ * of the page.
+ */
+ memset(bh->b_data, 0, bh->b_size);
+ }
+
+ dec_count((struct io_context *) bh->b_private,
+ bh_get_region(bh), !uptodate);
+ mempool_free(bh, _buffer_pool);
+}
+
+/*
+ * Primitives for alignment calculations.
+ */
+int fls(unsigned n)
+{
+ return generic_fls32(n);
+}
+
+static inline int log2_floor(unsigned n)
+{
+ return ffs(n) - 1;
+}
+
+static inline int log2_align(unsigned n)
+{
+ return fls(n) - 1;
+}
+
+/*
+ * Returns the next block for io.
+ */
+static int do_page(kdev_t dev, sector_t *block, sector_t end_block,
+ unsigned int block_size,
+ struct page *p, unsigned int offset,
+ unsigned int region, struct io_context *io)
+{
+ struct buffer_head *bh;
+ sector_t b = *block;
+ sector_t blocks_per_page = PAGE_SIZE / block_size;
+ unsigned int this_size; /* holds the size of the current io */
+ sector_t len;
+
+ if (!blocks_per_page) {
+ DMERR("dm-io: PAGE_SIZE (%lu) < block_size (%u) unsupported",
+ PAGE_SIZE, block_size);
+ return 0;
+ }
+
+ while ((offset < PAGE_SIZE) && (b != end_block)) {
+ bh = mempool_alloc(_buffer_pool, GFP_NOIO);
+ init_buffer(bh, endio, io);
+ bh_set_region(bh, region);
+
+ /*
+ * Block size must be a power of 2 and aligned
+ * correctly.
+ */
+
+ len = min(end_block - b, blocks_per_page);
+ len = min(len, blocks_per_page - offset / block_size);
+
+ if (!len) {
+ DMERR("dm-io: Invalid offset/block_size (%u/%u).",
+ offset, block_size);
+ return 0;
+ }
+
+ this_size = 1 << log2_align(len);
+ if (b)
+ this_size = min(this_size,
+ (unsigned) 1 << log2_floor(b));
+
+ /*
+ * Add in the job offset.
+ */
+ bh->b_blocknr = (b / this_size);
+ bh->b_size = block_size * this_size;
+ set_bh_page(bh, p, offset);
+ bh->b_this_page = bh;
+
+ bh->b_dev = dev;
+ atomic_set(&bh->b_count, 1);
+
+ bh->b_state = ((1 << BH_Uptodate) | (1 << BH_Mapped) |
+ (1 << BH_Lock));
+
+ if (io->rw == WRITE)
+ clear_bit(BH_Dirty, &bh->b_state);
+
+ atomic_inc(&io->count);
+ submit_bh(io->rw, bh);
+
+ b += this_size;
+ offset += block_size * this_size;
+ }
+
+ *block = b;
+ return (b == end_block);
+}
+
+static void do_region(unsigned int region, struct io_region *where,
+ struct page *page, unsigned int offset,
+ struct io_context *io)
+{
+ unsigned int block_size = get_hardsect_size(where->dev);
+ unsigned int sblock_size = block_size >> 9;
+ sector_t block = where->sector / sblock_size;
+ sector_t end_block = (where->sector + where->count) / sblock_size;
+
+ while (1) {
+ if (do_page(where->dev, &block, end_block, block_size,
+ page, offset, region, io))
+ break;
+
+ offset = 0; /* only offset the first page */
+
+ page = list_entry(page->list.next, struct page, list);
+ }
+}
+
+static void dispatch_io(unsigned int num_regions, struct io_region *where,
+ struct page *pages, unsigned int offset,
+ struct io_context *io)
+{
+ int i;
+
+ for (i = 0; i < num_regions; i++)
+ if (where[i].count)
+ do_region(i, where + i, pages, offset, io);
+
+ /*
+ * Drop the extra refence that we were holding to avoid
+ * the io being completed too early.
+ */
+ dec_count(io, 0, 0);
+}
+
+/*
+ * Synchronous io
+ */
+int dm_io_sync(unsigned int num_regions, struct io_region *where,
+ int rw, struct page *pages, unsigned int offset,
+ unsigned int *error_bits)
+{
+ struct io_context io;
+
+ BUG_ON(num_regions > 1 && rw != WRITE);
+
+ io.rw = rw;
+ io.error = 0;
+ atomic_set(&io.count, 1); /* see dispatch_io() */
+ io.sleeper = current;
+
+ dispatch_io(num_regions, where, pages, offset, &io);
+ run_task_queue(&tq_disk);
+
+ while (1) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+
+ if (!atomic_read(&io.count))
+ break;
+
+ schedule();
+ }
+ set_current_state(TASK_RUNNING);
+
+ *error_bits = io.error;
+ return io.error ? -EIO : 0;
+}
+
+/*
+ * Asynchronous io
+ */
+int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
+ struct page *pages, unsigned int offset,
+ io_notify_fn fn, void *context)
+{
+ struct io_context *io = mempool_alloc(_io_pool, GFP_NOIO);
+
+ io->rw = rw;
+ io->error = 0;
+ atomic_set(&io->count, 1); /* see dispatch_io() */
+ io->sleeper = NULL;
+ io->callback = fn;
+ io->context = context;
+
+ dispatch_io(num_regions, where, pages, offset, io);
+ return 0;
+}
+
+EXPORT_SYMBOL(dm_io_get);
+EXPORT_SYMBOL(dm_io_put);
+EXPORT_SYMBOL(dm_io_sync);
+EXPORT_SYMBOL(dm_io_async);
--- linux-2.4.26-rc1/drivers/md/dm-io.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-io.h Wed Mar 31 13:48:32 2004
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _DM_IO_H
+#define _DM_IO_H
+
+#include "dm.h"
+
+#include <linux/list.h>
+
+/* Move these to bitops.h eventually */
+/* Improved generic_fls algorithm (in 2.4 there is no generic_fls so far) */
+/* (c) 2002, D.Phillips and Sistina Software */
+/* Licensed under Version 2 of the GPL */
+
+static unsigned generic_fls8(unsigned n)
+{
+ return n & 0xf0 ?
+ n & 0xc0 ? (n >> 7) + 7 : (n >> 5) + 5:
+ n & 0x0c ? (n >> 3) + 3 : n - ((n + 1) >> 2);
+}
+
+static inline unsigned generic_fls16(unsigned n)
+{
+ return n & 0xff00? generic_fls8(n >> 8) + 8 : generic_fls8(n);
+}
+
+static inline unsigned generic_fls32(unsigned n)
+{
+ return n & 0xffff0000 ? generic_fls16(n >> 16) + 16 : generic_fls16(n);
+}
+
+/* FIXME make this configurable */
+#define DM_MAX_IO_REGIONS 8
+
+struct io_region {
+ kdev_t dev;
+ sector_t sector;
+ sector_t count;
+};
+
+
+/*
+ * 'error' is a bitset, with each bit indicating whether an error
+ * occurred doing io to the corresponding region.
+ */
+typedef void (*io_notify_fn)(unsigned int error, void *context);
+
+
+/*
+ * Before anyone uses the IO interface they should call
+ * dm_io_get(), specifying roughly how many pages they are
+ * expecting to perform io on concurrently.
+ *
+ * This function may block.
+ */
+int dm_io_get(unsigned int num_pages);
+void dm_io_put(unsigned int num_pages);
+
+
+/*
+ * Synchronous IO.
+ *
+ * Please ensure that the rw flag in the next two functions is
+ * either READ or WRITE, ie. we don't take READA. Any
+ * regions with a zero count field will be ignored.
+ */
+int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
+ struct page *pages, unsigned int offset,
+ unsigned int *error_bits);
+
+
+/*
+ * Aynchronous IO.
+ *
+ * The 'where' array may be safely allocated on the stack since
+ * the function takes a copy.
+ */
+int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
+ struct page *pages, unsigned int offset,
+ io_notify_fn fn, void *context);
+
+#endif
--- linux-2.4.26-rc1/drivers/md/dm-ioctl.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-ioctl.c Wed Mar 31 14:02:59 2004
@@ -0,0 +1,1366 @@
+/*
+ * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/miscdevice.h>
+#include <linux/dm-ioctl.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/blk.h>
+#include <linux/slab.h>
+
+#include <asm/uaccess.h>
+
+#define DM_DRIVER_EMAIL "dm-devel@redhat.com"
+
+/*-----------------------------------------------------------------
+ * The ioctl interface needs to be able to look up devices by
+ * name or uuid.
+ *---------------------------------------------------------------*/
+struct hash_cell {
+ struct list_head name_list;
+ struct list_head uuid_list;
+
+ char *name;
+ char *uuid;
+ struct mapped_device *md;
+ struct dm_table *new_map;
+
+ /* I hate devfs */
+ devfs_handle_t devfs_entry;
+};
+
+struct vers_iter {
+ size_t param_size;
+ struct dm_target_versions *vers, *old_vers;
+ char *end;
+ uint32_t flags;
+};
+
+#define NUM_BUCKETS 64
+#define MASK_BUCKETS (NUM_BUCKETS - 1)
+static struct list_head _name_buckets[NUM_BUCKETS];
+static struct list_head _uuid_buckets[NUM_BUCKETS];
+
+static devfs_handle_t _dev_dir;
+void dm_hash_remove_all(void);
+
+/*
+ * Guards access to both hash tables.
+ */
+static DECLARE_RWSEM(_hash_lock);
+
+static void init_buckets(struct list_head *buckets)
+{
+ unsigned int i;
+
+ for (i = 0; i < NUM_BUCKETS; i++)
+ INIT_LIST_HEAD(buckets + i);
+}
+
+int dm_hash_init(void)
+{
+ init_buckets(_name_buckets);
+ init_buckets(_uuid_buckets);
+ _dev_dir = devfs_mk_dir(0, DM_DIR, NULL);
+ return 0;
+}
+
+void dm_hash_exit(void)
+{
+ dm_hash_remove_all();
+ devfs_unregister(_dev_dir);
+}
+
+/*-----------------------------------------------------------------
+ * Hash function:
+ * We're not really concerned with the str hash function being
+ * fast since it's only used by the ioctl interface.
+ *---------------------------------------------------------------*/
+static unsigned int hash_str(const char *str)
+{
+ const unsigned int hash_mult = 2654435387U;
+ unsigned int h = 0;
+
+ while (*str)
+ h = (h + (unsigned int) *str++) * hash_mult;
+
+ return h & MASK_BUCKETS;
+}
+
+/*-----------------------------------------------------------------
+ * Code for looking up a device by name
+ *---------------------------------------------------------------*/
+static struct hash_cell *__get_name_cell(const char *str)
+{
+ struct list_head *tmp;
+ struct hash_cell *hc;
+ unsigned int h = hash_str(str);
+
+ list_for_each (tmp, _name_buckets + h) {
+ hc = list_entry(tmp, struct hash_cell, name_list);
+ if (!strcmp(hc->name, str))
+ return hc;
+ }
+
+ return NULL;
+}
+
+static struct hash_cell *__get_uuid_cell(const char *str)
+{
+ struct list_head *tmp;
+ struct hash_cell *hc;
+ unsigned int h = hash_str(str);
+
+ list_for_each (tmp, _uuid_buckets + h) {
+ hc = list_entry(tmp, struct hash_cell, uuid_list);
+ if (!strcmp(hc->uuid, str))
+ return hc;
+ }
+
+ return NULL;
+}
+
+/*-----------------------------------------------------------------
+ * Inserting, removing and renaming a device.
+ *---------------------------------------------------------------*/
+static inline char *kstrdup(const char *str)
+{
+ char *r = kmalloc(strlen(str) + 1, GFP_KERNEL);
+ if (r)
+ strcpy(r, str);
+ return r;
+}
+
+static struct hash_cell *alloc_cell(const char *name, const char *uuid,
+ struct mapped_device *md)
+{
+ struct hash_cell *hc;
+
+ hc = kmalloc(sizeof(*hc), GFP_KERNEL);
+ if (!hc)
+ return NULL;
+
+ hc->name = kstrdup(name);
+ if (!hc->name) {
+ kfree(hc);
+ return NULL;
+ }
+
+ if (!uuid)
+ hc->uuid = NULL;
+
+ else {
+ hc->uuid = kstrdup(uuid);
+ if (!hc->uuid) {
+ kfree(hc->name);
+ kfree(hc);
+ return NULL;
+ }
+ }
+
+ INIT_LIST_HEAD(&hc->name_list);
+ INIT_LIST_HEAD(&hc->uuid_list);
+ hc->md = md;
+ hc->new_map = NULL;
+ return hc;
+}
+
+static void free_cell(struct hash_cell *hc)
+{
+ if (hc) {
+ kfree(hc->name);
+ kfree(hc->uuid);
+ kfree(hc);
+ }
+}
+
+/*
+ * devfs stuff.
+ */
+static int register_with_devfs(struct hash_cell *hc)
+{
+ kdev_t dev = dm_kdev(hc->md);
+
+ hc->devfs_entry =
+ devfs_register(_dev_dir, hc->name, DEVFS_FL_CURRENT_OWNER,
+ major(dev), minor(dev),
+ S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
+ &dm_blk_dops, NULL);
+
+ return 0;
+}
+
+static int unregister_with_devfs(struct hash_cell *hc)
+{
+ devfs_unregister(hc->devfs_entry);
+ return 0;
+}
+
+/*
+ * The kdev_t and uuid of a device can never change once it is
+ * initially inserted.
+ */
+int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
+{
+ struct hash_cell *cell;
+
+ /*
+ * Allocate the new cells.
+ */
+ cell = alloc_cell(name, uuid, md);
+ if (!cell)
+ return -ENOMEM;
+
+ /*
+ * Insert the cell into both hash tables.
+ */
+ down_write(&_hash_lock);
+ if (__get_name_cell(name))
+ goto bad;
+
+ list_add(&cell->name_list, _name_buckets + hash_str(name));
+
+ if (uuid) {
+ if (__get_uuid_cell(uuid)) {
+ list_del(&cell->name_list);
+ goto bad;
+ }
+ list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
+ }
+ register_with_devfs(cell);
+ dm_get(md);
+ up_write(&_hash_lock);
+
+ return 0;
+
+ bad:
+ up_write(&_hash_lock);
+ free_cell(cell);
+ return -EBUSY;
+}
+
+void __hash_remove(struct hash_cell *hc)
+{
+ /* remove from the dev hash */
+ list_del(&hc->uuid_list);
+ list_del(&hc->name_list);
+ unregister_with_devfs(hc);
+ dm_put(hc->md);
+ if (hc->new_map)
+ dm_table_put(hc->new_map);
+ free_cell(hc);
+}
+
+void dm_hash_remove_all(void)
+{
+ int i;
+ struct hash_cell *hc;
+ struct list_head *tmp, *n;
+
+ down_write(&_hash_lock);
+ for (i = 0; i < NUM_BUCKETS; i++) {
+ list_for_each_safe (tmp, n, _name_buckets + i) {
+ hc = list_entry(tmp, struct hash_cell, name_list);
+ __hash_remove(hc);
+ }
+ }
+ up_write(&_hash_lock);
+}
+
+int dm_hash_rename(const char *old, const char *new)
+{
+ char *new_name, *old_name;
+ struct hash_cell *hc;
+
+ /*
+ * duplicate new.
+ */
+ new_name = kstrdup(new);
+ if (!new_name)
+ return -ENOMEM;
+
+ down_write(&_hash_lock);
+
+ /*
+ * Is new free ?
+ */
+ hc = __get_name_cell(new);
+ if (hc) {
+ DMWARN("asked to rename to an already existing name %s -> %s",
+ old, new);
+ up_write(&_hash_lock);
+ kfree(new_name);
+ return -EBUSY;
+ }
+
+ /*
+ * Is there such a device as 'old' ?
+ */
+ hc = __get_name_cell(old);
+ if (!hc) {
+ DMWARN("asked to rename a non existent device %s -> %s",
+ old, new);
+ up_write(&_hash_lock);
+ kfree(new_name);
+ return -ENXIO;
+ }
+
+ /*
+ * rename and move the name cell.
+ */
+ list_del(&hc->name_list);
+ old_name = hc->name;
+ hc->name = new_name;
+ list_add(&hc->name_list, _name_buckets + hash_str(new_name));
+
+ /* rename the device node in devfs */
+ unregister_with_devfs(hc);
+ register_with_devfs(hc);
+
+ up_write(&_hash_lock);
+ kfree(old_name);
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * Implementation of the ioctl commands
+ *---------------------------------------------------------------*/
+/*
+ * All the ioctl commands get dispatched to functions with this
+ * prototype.
+ */
+typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
+
+static int remove_all(struct dm_ioctl *param, size_t param_size)
+{
+ dm_hash_remove_all();
+ param->data_size = 0;
+ return 0;
+}
+
+/*
+ * Round up the ptr to an 8-byte boundary.
+ */
+#define ALIGN_MASK 7
+static inline void *align_ptr(void *ptr)
+{
+ return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
+}
+
+/*
+ * Retrieves the data payload buffer from an already allocated
+ * struct dm_ioctl.
+ */
+static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
+ size_t *len)
+{
+ param->data_start = align_ptr(param + 1) - (void *) param;
+
+ if (param->data_start < param_size)
+ *len = param_size - param->data_start;
+ else
+ *len = 0;
+
+ return ((void *) param) + param->data_start;
+}
+
+static int list_devices(struct dm_ioctl *param, size_t param_size)
+{
+ unsigned int i;
+ struct hash_cell *hc;
+ size_t len, needed = 0;
+ struct dm_name_list *nl, *old_nl = NULL;
+
+ down_write(&_hash_lock);
+
+ /*
+ * Loop through all the devices working out how much
+ * space we need.
+ */
+ for (i = 0; i < NUM_BUCKETS; i++) {
+ list_for_each_entry (hc, _name_buckets + i, name_list) {
+ needed += sizeof(struct dm_name_list);
+ needed += strlen(hc->name) + 1;
+ needed += ALIGN_MASK;
+ }
+ }
+
+ /*
+ * Grab our output buffer.
+ */
+ nl = get_result_buffer(param, param_size, &len);
+ if (len < needed) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ goto out;
+ }
+ param->data_size = param->data_start + needed;
+
+ nl->dev = 0; /* Flags no data */
+
+ /*
+ * Now loop through filling out the names.
+ */
+ for (i = 0; i < NUM_BUCKETS; i++) {
+ list_for_each_entry (hc, _name_buckets + i, name_list) {
+ if (old_nl)
+ old_nl->next = (uint32_t) ((void *) nl -
+ (void *) old_nl);
+
+ nl->dev = dm_kdev(hc->md);
+ nl->next = 0;
+ strcpy(nl->name, hc->name);
+
+ old_nl = nl;
+ nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
+ }
+ }
+
+ out:
+ up_write(&_hash_lock);
+ return 0;
+}
+
+static void list_version_get_needed(struct target_type *tt, void *param)
+{
+ int *needed = param;
+
+ *needed += strlen(tt->name);
+ *needed += sizeof(tt->version);
+ *needed += ALIGN_MASK;
+}
+
+static void list_version_get_info(struct target_type *tt, void *param)
+{
+ struct vers_iter *info = param;
+
+ /* Check space - it might have changed since the first iteration */
+ if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
+ info->end) {
+ info->flags = DM_BUFFER_FULL_FLAG;
+ return;
+ }
+
+ if (info->old_vers)
+ info->old_vers->next = (uint32_t) ((void *)info->vers -
+ (void *)info->old_vers);
+
+ info->vers->version[0] = tt->version[0];
+ info->vers->version[1] = tt->version[1];
+ info->vers->version[2] = tt->version[2];
+ info->vers->next = 0;
+ strcpy(info->vers->name, tt->name);
+
+ info->old_vers = info->vers;
+ info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
+}
+
+static int list_versions(struct dm_ioctl *param, size_t param_size)
+{
+ size_t len, needed = 0;
+ struct dm_target_versions *vers;
+ struct vers_iter iter_info;
+
+ /*
+ * Loop through all the devices working out how much
+ * space we need.
+ */
+ dm_target_iterate(list_version_get_needed, &needed);
+
+ /*
+ * Grab our output buffer.
+ */
+ vers = get_result_buffer(param, param_size, &len);
+ if (len < needed) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ goto out;
+ }
+ param->data_size = param->data_start + needed;
+
+ iter_info.param_size = param_size;
+ iter_info.old_vers = NULL;
+ iter_info.vers = vers;
+ iter_info.flags = 0;
+ iter_info.end = (char *)vers+len;
+
+ /*
+ * Now loop through filling out the names & versions.
+ */
+ dm_target_iterate(list_version_get_info, &iter_info);
+ param->flags |= iter_info.flags;
+
+ out:
+ return 0;
+}
+
+static int check_name(const char *name)
+{
+ if (strchr(name, '/')) {
+ DMWARN("invalid device name");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Fills in a dm_ioctl structure, ready for sending back to
+ * userland.
+ */
+static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
+{
+ kdev_t dev = dm_kdev(md);
+ struct dm_table *table;
+ struct block_device *bdev;
+
+ param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
+ DM_ACTIVE_PRESENT_FLAG);
+
+ if (dm_suspended(md))
+ param->flags |= DM_SUSPEND_FLAG;
+
+ param->dev = kdev_t_to_nr(dev);
+
+ if (is_read_only(dev))
+ param->flags |= DM_READONLY_FLAG;
+
+ param->event_nr = dm_get_event_nr(md);
+
+ table = dm_get_table(md);
+ if (table) {
+ param->flags |= DM_ACTIVE_PRESENT_FLAG;
+ param->target_count = dm_table_get_num_targets(table);
+ dm_table_put(table);
+ } else
+ param->target_count = 0;
+
+ bdev = bdget(param->dev);
+ if (!bdev)
+ return -ENXIO;
+ param->open_count = bdev->bd_openers;
+ bdput(bdev);
+
+ return 0;
+}
+
+static int dev_create(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ kdev_t dev = 0;
+ struct mapped_device *md;
+
+ r = check_name(param->name);
+ if (r)
+ return r;
+
+ if (param->flags & DM_PERSISTENT_DEV_FLAG)
+ dev = to_kdev_t(param->dev);
+
+ r = dm_create(dev, &md);
+ if (r)
+ return r;
+
+ r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
+ if (r) {
+ dm_put(md);
+ return r;
+ }
+
+ param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+ r = __dev_status(md, param);
+ dm_put(md);
+
+ return r;
+}
+
+/*
+ * Always use UUID for lookups if it's present, otherwise use name.
+ */
+static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
+{
+ return *param->uuid ?
+ __get_uuid_cell(param->uuid) : __get_name_cell(param->name);
+}
+
+static inline struct mapped_device *find_device(struct dm_ioctl *param)
+{
+ struct hash_cell *hc;
+ struct mapped_device *md = NULL;
+
+ down_read(&_hash_lock);
+ hc = __find_device_hash_cell(param);
+ if (hc) {
+ md = hc->md;
+
+ /*
+ * Sneakily write in both the name and the uuid
+ * while we have the cell.
+ */
+ strncpy(param->name, hc->name, sizeof(param->name));
+ if (hc->uuid)
+ strncpy(param->uuid, hc->uuid, sizeof(param->uuid) - 1);
+ else
+ param->uuid[0] = '\0';
+
+ if (hc->new_map)
+ param->flags |= DM_INACTIVE_PRESENT_FLAG;
+ else
+ param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+ dm_get(md);
+ }
+ up_read(&_hash_lock);
+
+ return md;
+}
+
+static int dev_remove(struct dm_ioctl *param, size_t param_size)
+{
+ struct hash_cell *hc;
+
+ down_write(&_hash_lock);
+ hc = __find_device_hash_cell(param);
+
+ if (!hc) {
+ DMWARN("device doesn't appear to be in the dev hash table.");
+ up_write(&_hash_lock);
+ return -ENXIO;
+ }
+
+ __hash_remove(hc);
+ up_write(&_hash_lock);
+ param->data_size = 0;
+ return 0;
+}
+
+/*
+ * Check a string doesn't overrun the chunk of
+ * memory we copied from userland.
+ */
+static int invalid_str(char *str, void *end)
+{
+ while ((void *) str < end)
+ if (!*str++)
+ return 0;
+
+ return -EINVAL;
+}
+
+static int dev_rename(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ char *new_name = (char *) param + param->data_start;
+
+ if (new_name < (char *) (param + 1) ||
+ invalid_str(new_name, (void *) param + param_size)) {
+ DMWARN("Invalid new logical volume name supplied.");
+ return -EINVAL;
+ }
+
+ r = check_name(new_name);
+ if (r)
+ return r;
+
+ param->data_size = 0;
+ return dm_hash_rename(param->name, new_name);
+}
+
+static int do_suspend(struct dm_ioctl *param)
+{
+ int r = 0;
+ struct mapped_device *md;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ if (!dm_suspended(md))
+ r = dm_suspend(md);
+
+ if (!r)
+ r = __dev_status(md, param);
+
+ dm_put(md);
+ return r;
+}
+
+static int do_resume(struct dm_ioctl *param)
+{
+ int r = 0;
+ struct hash_cell *hc;
+ struct mapped_device *md;
+ struct dm_table *new_map;
+
+ down_write(&_hash_lock);
+
+ hc = __find_device_hash_cell(param);
+ if (!hc) {
+ DMWARN("device doesn't appear to be in the dev hash table.");
+ up_write(&_hash_lock);
+ return -ENXIO;
+ }
+
+ md = hc->md;
+ dm_get(md);
+
+ new_map = hc->new_map;
+ hc->new_map = NULL;
+ param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+ up_write(&_hash_lock);
+
+ /* Do we need to load a new map ? */
+ if (new_map) {
+ /* Suspend if it isn't already suspended */
+ if (!dm_suspended(md))
+ dm_suspend(md);
+
+ r = dm_swap_table(md, new_map);
+ if (r) {
+ dm_put(md);
+ dm_table_put(new_map);
+ return r;
+ }
+
+ if (dm_table_get_mode(new_map) & FMODE_WRITE)
+ set_device_ro(dm_kdev(md), 0);
+ else
+ set_device_ro(dm_kdev(md), 1);
+
+ dm_table_put(new_map);
+ }
+
+ if (dm_suspended(md))
+ r = dm_resume(md);
+
+ if (!r)
+ r = __dev_status(md, param);
+
+ dm_put(md);
+ return r;
+}
+
+/*
+ * Set or unset the suspension state of a device.
+ * If the device already is in the requested state we just return its status.
+ */
+static int dev_suspend(struct dm_ioctl *param, size_t param_size)
+{
+ if (param->flags & DM_SUSPEND_FLAG)
+ return do_suspend(param);
+
+ return do_resume(param);
+}
+
+/*
+ * Copies device info back to user space, used by
+ * the create and info ioctls.
+ */
+static int dev_status(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct mapped_device *md;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ r = __dev_status(md, param);
+ dm_put(md);
+ return r;
+}
+
+/*
+ * Build up the status struct for each target
+ */
+static void retrieve_status(struct dm_table *table, struct dm_ioctl *param,
+ size_t param_size)
+{
+ unsigned int i, num_targets;
+ struct dm_target_spec *spec;
+ char *outbuf, *outptr;
+ status_type_t type;
+ size_t remaining, len, used = 0;
+
+ outptr = outbuf = get_result_buffer(param, param_size, &len);
+
+ if (param->flags & DM_STATUS_TABLE_FLAG)
+ type = STATUSTYPE_TABLE;
+ else
+ type = STATUSTYPE_INFO;
+
+ /* Get all the target info */
+ num_targets = dm_table_get_num_targets(table);
+ for (i = 0; i < num_targets; i++) {
+ struct dm_target *ti = dm_table_get_target(table, i);
+
+ remaining = len - (outptr - outbuf);
+ if (remaining <= sizeof(struct dm_target_spec)) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ break;
+ }
+
+ spec = (struct dm_target_spec *) outptr;
+
+ spec->status = 0;
+ spec->sector_start = ti->begin;
+ spec->length = ti->len;
+ strncpy(spec->target_type, ti->type->name,
+ sizeof(spec->target_type));
+
+ outptr += sizeof(struct dm_target_spec);
+ remaining = len - (outptr - outbuf);
+
+ /* Get the status/table string from the target driver */
+ if (ti->type->status) {
+ if (ti->type->status(ti, type, outptr, remaining)) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ break;
+ }
+ } else
+ outptr[0] = '\0';
+
+ outptr += strlen(outptr) + 1;
+ used = param->data_start + (outptr - outbuf);
+
+ align_ptr(outptr);
+ spec->next = outptr - outbuf;
+ }
+
+ if (used)
+ param->data_size = used;
+
+ param->target_count = num_targets;
+}
+
+/*
+ * Wait for a device to report an event
+ */
+static int dev_wait(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct mapped_device *md;
+ struct dm_table *table;
+ DECLARE_WAITQUEUE(wq, current);
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ /*
+ * Wait for a notification event
+ */
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!dm_add_wait_queue(md, &wq, param->event_nr)) {
+ schedule();
+ dm_remove_wait_queue(md, &wq);
+ }
+ set_current_state(TASK_RUNNING);
+
+ /*
+ * The userland program is going to want to know what
+ * changed to trigger the event, so we may as well tell
+ * him and save an ioctl.
+ */
+ r = __dev_status(md, param);
+ if (r)
+ goto out;
+
+ table = dm_get_table(md);
+ if (table) {
+ retrieve_status(table, param, param_size);
+ dm_table_put(table);
+ }
+
+ out:
+ dm_put(md);
+ return r;
+}
+
+static inline int get_mode(struct dm_ioctl *param)
+{
+ int mode = FMODE_READ | FMODE_WRITE;
+
+ if (param->flags & DM_READONLY_FLAG)
+ mode = FMODE_READ;
+
+ return mode;
+}
+
+static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
+ struct dm_target_spec **spec, char **target_params)
+{
+ *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
+ *target_params = (char *) (*spec + 1);
+
+ if (*spec < (last + 1))
+ return -EINVAL;
+
+ return invalid_str(*target_params, end);
+}
+
+static int populate_table(struct dm_table *table, struct dm_ioctl *param,
+ size_t param_size)
+{
+ int r;
+ unsigned int i = 0;
+ struct dm_target_spec *spec = (struct dm_target_spec *) param;
+ uint32_t next = param->data_start;
+ void *end = (void *) param + param_size;
+ char *target_params;
+
+ if (!param->target_count) {
+ DMWARN("populate_table: no targets specified");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < param->target_count; i++) {
+
+ r = next_target(spec, next, end, &spec, &target_params);
+ if (r) {
+ DMWARN("unable to find target");
+ return r;
+ }
+
+ r = dm_table_add_target(table, spec->target_type,
+ (sector_t) spec->sector_start,
+ (sector_t) spec->length,
+ target_params);
+ if (r) {
+ DMWARN("error adding target to table");
+ return r;
+ }
+
+ next = spec->next;
+ }
+
+ return dm_table_complete(table);
+}
+
+static int table_load(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct hash_cell *hc;
+ struct dm_table *t;
+
+ r = dm_table_create(&t, get_mode(param), param->target_count);
+ if (r)
+ return r;
+
+ r = populate_table(t, param, param_size);
+ if (r) {
+ dm_table_put(t);
+ return r;
+ }
+
+ down_write(&_hash_lock);
+ hc = __find_device_hash_cell(param);
+ if (!hc) {
+ DMWARN("device doesn't appear to be in the dev hash table.");
+ up_write(&_hash_lock);
+ return -ENXIO;
+ }
+
+ if (hc->new_map)
+ dm_table_put(hc->new_map);
+ hc->new_map = t;
+ param->flags |= DM_INACTIVE_PRESENT_FLAG;
+
+ r = __dev_status(hc->md, param);
+ up_write(&_hash_lock);
+ return r;
+}
+
+static int table_clear(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct hash_cell *hc;
+
+ down_write(&_hash_lock);
+
+ hc = __find_device_hash_cell(param);
+ if (!hc) {
+ DMWARN("device doesn't appear to be in the dev hash table.");
+ up_write(&_hash_lock);
+ return -ENXIO;
+ }
+
+ if (hc->new_map) {
+ dm_table_put(hc->new_map);
+ hc->new_map = NULL;
+ }
+
+ param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+ r = __dev_status(hc->md, param);
+ up_write(&_hash_lock);
+ return r;
+}
+
+/*
+ * Retrieves a list of devices used by a particular dm device.
+ */
+static void retrieve_deps(struct dm_table *table, struct dm_ioctl *param,
+ size_t param_size)
+{
+ unsigned int count = 0;
+ struct list_head *tmp;
+ size_t len, needed;
+ struct dm_target_deps *deps;
+
+ deps = get_result_buffer(param, param_size, &len);
+
+ /*
+ * Count the devices.
+ */
+ list_for_each(tmp, dm_table_get_devices(table))
+ count++;
+
+ /*
+ * Check we have enough space.
+ */
+ needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
+ if (len < needed) {
+ param->flags |= DM_BUFFER_FULL_FLAG;
+ return;
+ }
+
+ /*
+ * Fill in the devices.
+ */
+ deps->count = count;
+ count = 0;
+ list_for_each(tmp, dm_table_get_devices(table)) {
+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+ deps->dev[count++] = dd->bdev->bd_dev;
+ }
+
+ param->data_size = param->data_start + needed;
+}
+
+static int table_deps(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct mapped_device *md;
+ struct dm_table *table;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ r = __dev_status(md, param);
+ if (r)
+ goto out;
+
+ table = dm_get_table(md);
+ if (table) {
+ retrieve_deps(table, param, param_size);
+ dm_table_put(table);
+ }
+
+ out:
+ dm_put(md);
+ return r;
+}
+
+/*
+ * Return the status of a device as a text string for each
+ * target.
+ */
+static int table_status(struct dm_ioctl *param, size_t param_size)
+{
+ int r;
+ struct mapped_device *md;
+ struct dm_table *table;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ r = __dev_status(md, param);
+ if (r)
+ goto out;
+
+ table = dm_get_table(md);
+ if (table) {
+ retrieve_status(table, param, param_size);
+ dm_table_put(table);
+ }
+
+ out:
+ dm_put(md);
+ return r;
+}
+
+/*-----------------------------------------------------------------
+ * Implementation of open/close/ioctl on the special char
+ * device.
+ *---------------------------------------------------------------*/
+static ioctl_fn lookup_ioctl(unsigned int cmd)
+{
+ static struct {
+ int cmd;
+ ioctl_fn fn;
+ } _ioctls[] = {
+ {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
+ {DM_REMOVE_ALL_CMD, remove_all},
+ {DM_LIST_DEVICES_CMD, list_devices},
+
+ {DM_DEV_CREATE_CMD, dev_create},
+ {DM_DEV_REMOVE_CMD, dev_remove},
+ {DM_DEV_RENAME_CMD, dev_rename},
+ {DM_DEV_SUSPEND_CMD, dev_suspend},
+ {DM_DEV_STATUS_CMD, dev_status},
+ {DM_DEV_WAIT_CMD, dev_wait},
+
+ {DM_TABLE_LOAD_CMD, table_load},
+ {DM_TABLE_CLEAR_CMD, table_clear},
+ {DM_TABLE_DEPS_CMD, table_deps},
+ {DM_TABLE_STATUS_CMD, table_status},
+
+ {DM_LIST_VERSIONS_CMD, list_versions}
+ };
+
+ return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
+}
+
+/*
+ * As well as checking the version compatibility this always
+ * copies the kernel interface version out.
+ */
+static int check_version(unsigned int cmd, struct dm_ioctl *user)
+{
+ uint32_t version[3];
+ int r = 0;
+
+ if (copy_from_user(version, user->version, sizeof(version)))
+ return -EFAULT;
+
+ if ((DM_VERSION_MAJOR != version[0]) ||
+ (DM_VERSION_MINOR < version[1])) {
+ DMWARN("ioctl interface mismatch: "
+ "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
+ DM_VERSION_MAJOR, DM_VERSION_MINOR,
+ DM_VERSION_PATCHLEVEL,
+ version[0], version[1], version[2], cmd);
+ r = -EINVAL;
+ }
+
+ /*
+ * Fill in the kernel version.
+ */
+ version[0] = DM_VERSION_MAJOR;
+ version[1] = DM_VERSION_MINOR;
+ version[2] = DM_VERSION_PATCHLEVEL;
+ if (copy_to_user(user->version, version, sizeof(version)))
+ return -EFAULT;
+
+ return r;
+}
+
+static void free_params(struct dm_ioctl *param)
+{
+ vfree(param);
+}
+
+static int copy_params(struct dm_ioctl *user, struct dm_ioctl **param)
+{
+ struct dm_ioctl tmp, *dmi;
+
+ if (copy_from_user(&tmp, user, sizeof(tmp)))
+ return -EFAULT;
+
+ if (tmp.data_size < sizeof(tmp))
+ return -EINVAL;
+
+ dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
+ if (!dmi)
+ return -ENOMEM;
+
+ if (copy_from_user(dmi, user, tmp.data_size)) {
+ vfree(dmi);
+ return -EFAULT;
+ }
+
+ *param = dmi;
+ return 0;
+}
+
+static int validate_params(uint cmd, struct dm_ioctl *param)
+{
+ /* Always clear this flag */
+ param->flags &= ~DM_BUFFER_FULL_FLAG;
+
+ /* Ignores parameters */
+ if (cmd == DM_REMOVE_ALL_CMD || cmd == DM_LIST_DEVICES_CMD ||
+ cmd == DM_LIST_VERSIONS_CMD)
+ return 0;
+
+ /* Unless creating, either name or uuid but not both */
+ if (cmd != DM_DEV_CREATE_CMD) {
+ if ((!*param->uuid && !*param->name) ||
+ (*param->uuid && *param->name)) {
+ DMWARN("one of name or uuid must be supplied, cmd(%u)",
+ cmd);
+ return -EINVAL;
+ }
+ }
+
+ /* Ensure strings are terminated */
+ param->name[DM_NAME_LEN - 1] = '\0';
+ param->uuid[DM_UUID_LEN - 1] = '\0';
+
+ return 0;
+}
+
+static int ctl_ioctl(struct inode *inode, struct file *file,
+ uint command, ulong u)
+{
+ int r = 0;
+ unsigned int cmd;
+ struct dm_ioctl *param;
+ struct dm_ioctl *user = (struct dm_ioctl *) u;
+ ioctl_fn fn = NULL;
+ size_t param_size;
+
+ /* only root can play with this */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (_IOC_TYPE(command) != DM_IOCTL)
+ return -ENOTTY;
+
+ cmd = _IOC_NR(command);
+
+ /*
+ * Check the interface version passed in. This also
+ * writes out the kernel's interface version.
+ */
+ r = check_version(cmd, user);
+ if (r)
+ return r;
+
+ /*
+ * Nothing more to do for the version command.
+ */
+ if (cmd == DM_VERSION_CMD)
+ return 0;
+
+ fn = lookup_ioctl(cmd);
+ if (!fn) {
+ DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
+ return -ENOTTY;
+ }
+
+ /*
+ * FIXME: I don't like this, we're trying to avoid low
+ * memory issues when a device is suspended.
+ */
+ current->flags |= PF_MEMALLOC;
+
+ /*
+ * Copy the parameters into kernel space.
+ */
+ r = copy_params(user, ¶m);
+ if (r) {
+ current->flags &= ~PF_MEMALLOC;
+ return r;
+ }
+
+ r = validate_params(cmd, param);
+ if (r)
+ goto out;
+
+ param_size = param->data_size;
+ param->data_size = sizeof(*param);
+ r = fn(param, param_size);
+
+ /*
+ * Copy the results back to userland.
+ */
+ if (!r && copy_to_user(user, param, param->data_size))
+ r = -EFAULT;
+
+ out:
+ free_params(param);
+ current->flags &= ~PF_MEMALLOC;
+ return r;
+}
+
+static struct file_operations _ctl_fops = {
+ .ioctl = ctl_ioctl,
+ .owner = THIS_MODULE,
+};
+
+static devfs_handle_t _ctl_handle;
+
+static struct miscdevice _dm_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DM_NAME,
+ .fops = &_ctl_fops
+};
+
+/*
+ * Create misc character device and link to DM_DIR/control.
+ */
+int __init dm_interface_init(void)
+{
+ int r;
+ char rname[64];
+
+ r = dm_hash_init();
+ if (r)
+ return r;
+
+ r = misc_register(&_dm_misc);
+ if (r) {
+ DMERR("misc_register failed for control device");
+ dm_hash_exit();
+ return r;
+ }
+
+ r = devfs_generate_path(_dm_misc.devfs_handle, rname + 3,
+ sizeof rname - 3);
+ if (r == -ENOSYS)
+ goto done; /* devfs not present */
+
+ if (r < 0) {
+ DMERR("devfs_generate_path failed for control device");
+ goto failed;
+ }
+
+ strncpy(rname + r, "../", 3);
+ r = devfs_mk_symlink(NULL, DM_DIR "/control",
+ DEVFS_FL_DEFAULT, rname + r, &_ctl_handle, NULL);
+ if (r) {
+ DMERR("devfs_mk_symlink failed for control device");
+ goto failed;
+ }
+ devfs_auto_unregister(_dm_misc.devfs_handle, _ctl_handle);
+
+ done:
+ DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
+ DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
+ DM_DRIVER_EMAIL);
+ return 0;
+
+ failed:
+ misc_deregister(&_dm_misc);
+ dm_hash_exit();
+ return r;
+}
+
+void dm_interface_exit(void)
+{
+ if (misc_deregister(&_dm_misc) < 0)
+ DMERR("misc_deregister failed for control device");
+
+ dm_hash_exit();
+}
--- linux-2.4.26-rc1/drivers/md/dm-linear.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-linear.c Wed Mar 31 13:49:08 2004
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+
+/*
+ * Linear: maps a linear range of a device.
+ */
+struct linear_c {
+ struct dm_dev *dev;
+ sector_t start;
+};
+
+/*
+ * Construct a linear mapping: <dev_path> <offset>
+ */
+static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct linear_c *lc;
+
+ if (argc != 2) {
+ ti->error = "dm-linear: Invalid argument count";
+ return -EINVAL;
+ }
+
+ lc = kmalloc(sizeof(*lc), GFP_KERNEL);
+ if (lc == NULL) {
+ ti->error = "dm-linear: Cannot allocate linear context";
+ return -ENOMEM;
+ }
+
+ if (sscanf(argv[1], SECTOR_FORMAT, &lc->start) != 1) {
+ ti->error = "dm-linear: Invalid device sector";
+ goto bad;
+ }
+
+ if (dm_get_device(ti, argv[0], lc->start, ti->len,
+ dm_table_get_mode(ti->table), &lc->dev)) {
+ ti->error = "dm-linear: Device lookup failed";
+ goto bad;
+ }
+
+ ti->private = lc;
+ return 0;
+
+ bad:
+ kfree(lc);
+ return -EINVAL;
+}
+
+static void linear_dtr(struct dm_target *ti)
+{
+ struct linear_c *lc = (struct linear_c *) ti->private;
+
+ dm_put_device(ti, lc->dev);
+ kfree(lc);
+}
+
+static int linear_map(struct dm_target *ti, struct buffer_head *bh, int rw,
+ union map_info *map_context)
+{
+ struct linear_c *lc = (struct linear_c *) ti->private;
+
+ bh->b_rdev = lc->dev->dev;
+ bh->b_rsector = lc->start + (bh->b_rsector - ti->begin);
+
+ return 1;
+}
+
+static int linear_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct linear_c *lc = (struct linear_c *) ti->private;
+ kdev_t kdev;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ kdev = to_kdev_t(lc->dev->bdev->bd_dev);
+ snprintf(result, maxlen, "%s " SECTOR_FORMAT,
+ dm_kdevname(kdev), lc->start);
+ break;
+ }
+ return 0;
+}
+
+static struct target_type linear_target = {
+ .name = "linear",
+ .version= {1, 0, 1},
+ .module = THIS_MODULE,
+ .ctr = linear_ctr,
+ .dtr = linear_dtr,
+ .map = linear_map,
+ .status = linear_status,
+};
+
+int __init dm_linear_init(void)
+{
+ int r = dm_register_target(&linear_target);
+
+ if (r < 0)
+ DMERR("linear: register failed %d", r);
+
+ return r;
+}
+
+void dm_linear_exit(void)
+{
+ int r = dm_unregister_target(&linear_target);
+
+ if (r < 0)
+ DMERR("linear: unregister failed %d", r);
+}
--- linux-2.4.26-rc1/drivers/md/dm-log.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-log.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,310 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+
+#include "dm-log.h"
+#include "dm-io.h"
+
+static LIST_HEAD(_log_types);
+static spinlock_t _lock = SPIN_LOCK_UNLOCKED;
+
+int dm_register_dirty_log_type(struct dirty_log_type *type)
+{
+ spin_lock(&_lock);
+ type->use_count = 0;
+ if (type->module)
+ __MOD_INC_USE_COUNT(type->module);
+
+ list_add(&type->list, &_log_types);
+ spin_unlock(&_lock);
+
+ return 0;
+}
+
+int dm_unregister_dirty_log_type(struct dirty_log_type *type)
+{
+ spin_lock(&_lock);
+
+ if (type->use_count)
+ DMWARN("Attempt to unregister a log type that is still in use");
+ else {
+ list_del(&type->list);
+ if (type->module)
+ __MOD_DEC_USE_COUNT(type->module);
+ }
+
+ spin_unlock(&_lock);
+
+ return 0;
+}
+
+static struct dirty_log_type *get_type(const char *type_name)
+{
+ struct dirty_log_type *type;
+ struct list_head *tmp;
+
+ spin_lock(&_lock);
+ list_for_each (tmp, &_log_types) {
+ type = list_entry(tmp, struct dirty_log_type, list);
+ if (!strcmp(type_name, type->name)) {
+ type->use_count++;
+ spin_unlock(&_lock);
+ return type;
+ }
+ }
+
+ spin_unlock(&_lock);
+ return NULL;
+}
+
+static void put_type(struct dirty_log_type *type)
+{
+ spin_lock(&_lock);
+ type->use_count--;
+ spin_unlock(&_lock);
+}
+
+struct dirty_log *dm_create_dirty_log(const char *type_name, sector_t dev_size,
+ unsigned int argc, char **argv)
+{
+ struct dirty_log_type *type;
+ struct dirty_log *log;
+
+ log = kmalloc(sizeof(*log), GFP_KERNEL);
+ if (!log)
+ return NULL;
+
+ type = get_type(type_name);
+ if (!type) {
+ kfree(log);
+ return NULL;
+ }
+
+ log->type = type;
+ if (type->ctr(log, dev_size, argc, argv)) {
+ kfree(log);
+ put_type(type);
+ return NULL;
+ }
+
+ return log;
+}
+
+void dm_destroy_dirty_log(struct dirty_log *log)
+{
+ log->type->dtr(log);
+ put_type(log->type);
+ kfree(log);
+}
+
+
+/*-----------------------------------------------------------------
+ * In core log, ie. trivial, non-persistent
+ *
+ * For now we'll keep this simple and just have 2 bitsets, one
+ * for clean/dirty, the other for sync/nosync. The sync bitset
+ * will be freed when everything is in sync.
+ *
+ * FIXME: problems with a 64bit sector_t
+ *---------------------------------------------------------------*/
+struct core_log {
+ sector_t region_size;
+ unsigned int region_count;
+ unsigned long *clean_bits;
+ unsigned long *sync_bits;
+ unsigned long *recovering_bits; /* FIXME: this seems excessive */
+
+ int sync_search;
+};
+
+#define BYTE_SHIFT 3
+
+static int core_ctr(struct dirty_log *log, sector_t dev_size,
+ unsigned int argc, char **argv)
+{
+ struct core_log *clog;
+ sector_t region_size;
+ unsigned int region_count;
+ size_t bitset_size;
+
+ if (argc != 1) {
+ DMWARN("wrong number of arguments to core_log");
+ return -EINVAL;
+ }
+
+ if (sscanf(argv[0], SECTOR_FORMAT, ®ion_size) != 1) {
+ DMWARN("invalid region size string");
+ return -EINVAL;
+ }
+
+ region_count = dm_div_up(dev_size, region_size);
+
+ clog = kmalloc(sizeof(*clog), GFP_KERNEL);
+ if (!clog) {
+ DMWARN("couldn't allocate core log");
+ return -ENOMEM;
+ }
+
+ clog->region_size = region_size;
+ clog->region_count = region_count;
+
+ /*
+ * Work out how many words we need to hold the bitset.
+ */
+ bitset_size = dm_round_up(region_count,
+ sizeof(*clog->clean_bits) << BYTE_SHIFT);
+ bitset_size >>= BYTE_SHIFT;
+
+ clog->clean_bits = vmalloc(bitset_size);
+ if (!clog->clean_bits) {
+ DMWARN("couldn't allocate clean bitset");
+ kfree(clog);
+ return -ENOMEM;
+ }
+ memset(clog->clean_bits, -1, bitset_size);
+
+ clog->sync_bits = vmalloc(bitset_size);
+ if (!clog->sync_bits) {
+ DMWARN("couldn't allocate sync bitset");
+ vfree(clog->clean_bits);
+ kfree(clog);
+ return -ENOMEM;
+ }
+ memset(clog->sync_bits, 0, bitset_size);
+
+ clog->recovering_bits = vmalloc(bitset_size);
+ if (!clog->recovering_bits) {
+ DMWARN("couldn't allocate sync bitset");
+ vfree(clog->sync_bits);
+ vfree(clog->clean_bits);
+ kfree(clog);
+ return -ENOMEM;
+ }
+ memset(clog->recovering_bits, 0, bitset_size);
+ clog->sync_search = 0;
+ log->context = clog;
+ return 0;
+}
+
+static void core_dtr(struct dirty_log *log)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+ vfree(clog->clean_bits);
+ vfree(clog->sync_bits);
+ vfree(clog->recovering_bits);
+ kfree(clog);
+}
+
+static sector_t core_get_region_size(struct dirty_log *log)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+ return clog->region_size;
+}
+
+static int core_is_clean(struct dirty_log *log, region_t region)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+ return test_bit(region, clog->clean_bits);
+}
+
+static int core_in_sync(struct dirty_log *log, region_t region, int block)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+
+ return test_bit(region, clog->sync_bits) ? 1 : 0;
+}
+
+static int core_flush(struct dirty_log *log)
+{
+ /* no op */
+ return 0;
+}
+
+static void core_mark_region(struct dirty_log *log, region_t region)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+ clear_bit(region, clog->clean_bits);
+}
+
+static void core_clear_region(struct dirty_log *log, region_t region)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+ set_bit(region, clog->clean_bits);
+}
+
+static int core_get_resync_work(struct dirty_log *log, region_t *region)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+
+ if (clog->sync_search >= clog->region_count)
+ return 0;
+
+ do {
+ *region = find_next_zero_bit(clog->sync_bits,
+ clog->region_count,
+ clog->sync_search);
+ clog->sync_search = *region + 1;
+
+ if (*region == clog->region_count)
+ return 0;
+
+ } while (test_bit(*region, clog->recovering_bits));
+
+ set_bit(*region, clog->recovering_bits);
+ return 1;
+}
+
+static void core_complete_resync_work(struct dirty_log *log, region_t region,
+ int success)
+{
+ struct core_log *clog = (struct core_log *) log->context;
+
+ clear_bit(region, clog->recovering_bits);
+ if (success)
+ set_bit(region, clog->sync_bits);
+}
+
+static struct dirty_log_type _core_type = {
+ .name = "core",
+
+ .ctr = core_ctr,
+ .dtr = core_dtr,
+ .get_region_size = core_get_region_size,
+ .is_clean = core_is_clean,
+ .in_sync = core_in_sync,
+ .flush = core_flush,
+ .mark_region = core_mark_region,
+ .clear_region = core_clear_region,
+ .get_resync_work = core_get_resync_work,
+ .complete_resync_work = core_complete_resync_work
+};
+
+__init int dm_dirty_log_init(void)
+{
+ int r;
+
+ r = dm_register_dirty_log_type(&_core_type);
+ if (r)
+ DMWARN("couldn't register core log");
+
+ return r;
+}
+
+void dm_dirty_log_exit(void)
+{
+ dm_unregister_dirty_log_type(&_core_type);
+}
+
+EXPORT_SYMBOL(dm_register_dirty_log_type);
+EXPORT_SYMBOL(dm_unregister_dirty_log_type);
+EXPORT_SYMBOL(dm_dirty_log_init);
+EXPORT_SYMBOL(dm_dirty_log_exit);
+EXPORT_SYMBOL(dm_create_dirty_log);
+EXPORT_SYMBOL(dm_destroy_dirty_log);
--- linux-2.4.26-rc1/drivers/md/dm-log.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-log.h Wed Mar 31 13:48:32 2004
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef DM_DIRTY_LOG
+#define DM_DIRTY_LOG
+
+#include "dm.h"
+
+typedef sector_t region_t;
+
+struct dirty_log_type;
+
+struct dirty_log {
+ struct dirty_log_type *type;
+ void *context;
+};
+
+struct dirty_log_type {
+ struct list_head list;
+ const char *name;
+ struct module *module;
+ unsigned int use_count;
+
+ int (*ctr)(struct dirty_log *log, sector_t dev_size,
+ unsigned int argc, char **argv);
+ void (*dtr)(struct dirty_log *log);
+
+ /*
+ * Retrieves the smallest size of region that the log can
+ * deal with.
+ */
+ sector_t (*get_region_size)(struct dirty_log *log);
+
+ /*
+ * A predicate to say whether a region is clean or not.
+ * May block.
+ */
+ int (*is_clean)(struct dirty_log *log, region_t region);
+
+ /*
+ * Returns: 0, 1, -EWOULDBLOCK, < 0
+ *
+ * A predicate function to check the area given by
+ * [sector, sector + len) is in sync.
+ *
+ * If -EWOULDBLOCK is returned the state of the region is
+ * unknown, typically this will result in a read being
+ * passed to a daemon to deal with, since a daemon is
+ * allowed to block.
+ */
+ int (*in_sync)(struct dirty_log *log, region_t region, int can_block);
+
+ /*
+ * Flush the current log state (eg, to disk). This
+ * function may block.
+ */
+ int (*flush)(struct dirty_log *log);
+
+ /*
+ * Mark an area as clean or dirty. These functions may
+ * block, though for performance reasons blocking should
+ * be extremely rare (eg, allocating another chunk of
+ * memory for some reason).
+ */
+ void (*mark_region)(struct dirty_log *log, region_t region);
+ void (*clear_region)(struct dirty_log *log, region_t region);
+
+ /*
+ * Returns: <0 (error), 0 (no region), 1 (region)
+ *
+ * The mirrord will need perform recovery on regions of
+ * the mirror that are in the NOSYNC state. This
+ * function asks the log to tell the caller about the
+ * next region that this machine should recover.
+ *
+ * Do not confuse this function with 'in_sync()', one
+ * tells you if an area is synchronised, the other
+ * assigns recovery work.
+ */
+ int (*get_resync_work)(struct dirty_log *log, region_t *region);
+
+ /*
+ * This notifies the log that the resync of an area has
+ * been completed. The log should then mark this region
+ * as CLEAN.
+ */
+ void (*complete_resync_work)(struct dirty_log *log,
+ region_t region, int success);
+};
+
+int dm_register_dirty_log_type(struct dirty_log_type *type);
+int dm_unregister_dirty_log_type(struct dirty_log_type *type);
+
+
+/*
+ * Make sure you use these two functions, rather than calling
+ * type->constructor/destructor() directly.
+ */
+struct dirty_log *dm_create_dirty_log(const char *type_name, sector_t dev_size,
+ unsigned int argc, char **argv);
+void dm_destroy_dirty_log(struct dirty_log *log);
+
+/*
+ * init/exit functions.
+ */
+int dm_dirty_log_init(void);
+void dm_dirty_log_exit(void);
+
+#endif
--- linux-2.4.26-rc1/drivers/md/dm-raid1.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-raid1.c Wed Mar 31 13:49:14 2004
@@ -0,0 +1,1295 @@
+/*
+ * Copyright (C) 2003 Sistina Software Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-daemon.h"
+#include "dm-io.h"
+#include "dm-log.h"
+#include "kcopyd.h"
+
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/vmalloc.h>
+
+static struct dm_daemon _kmirrord;
+
+/*-----------------------------------------------------------------
+ * buffer lists:
+ *
+ * We play with singly linked lists of buffers, but we want to be
+ * careful to add new buffers to the back of the list, to avoid
+ * buffers being starved of attention.
+ *---------------------------------------------------------------*/
+struct buffer_list {
+ struct buffer_head *head;
+ struct buffer_head *tail;
+};
+
+static inline void buffer_list_init(struct buffer_list *bl)
+{
+ bl->head = bl->tail = NULL;
+}
+
+static inline void buffer_list_add(struct buffer_list *bl,
+ struct buffer_head *bh)
+{
+ bh->b_reqnext = NULL;
+
+ if (bl->tail) {
+ bl->tail->b_reqnext = bh;
+ bl->tail = bh;
+ } else
+ bl->head = bl->tail = bh;
+}
+
+static struct buffer_head *buffer_list_pop(struct buffer_list *bl)
+{
+ struct buffer_head *bh = bl->head;
+
+ if (bh) {
+ bl->head = bl->head->b_reqnext;
+ if (!bl->head)
+ bl->tail = NULL;
+
+ bh->b_reqnext = NULL;
+ }
+
+ return bh;
+}
+
+/*-----------------------------------------------------------------
+ * Region hash
+ *
+ * The mirror splits itself up into discrete regions. Each
+ * region can be in one of three states: clean, dirty,
+ * nosync. There is no need to put clean regions in the hash.
+ *
+ * In addition to being present in the hash table a region _may_
+ * be present on one of three lists.
+ *
+ * clean_regions: Regions on this list have no io pending to
+ * them, they are in sync, we are no longer interested in them,
+ * they are dull. rh_update_states() will remove them from the
+ * hash table.
+ *
+ * quiesced_regions: These regions have been spun down, ready
+ * for recovery. rh_recovery_start() will remove regions from
+ * this list and hand them to kmirrord, which will schedule the
+ * recovery io with kcopyd.
+ *
+ * recovered_regions: Regions that kcopyd has successfully
+ * recovered. rh_update_states() will now schedule any delayed
+ * io, up the recovery_count, and remove the region from the
+ * hash.
+ *
+ * There are 2 locks:
+ * A rw spin lock 'hash_lock' protects just the hash table,
+ * this is never held in write mode from interrupt context,
+ * which I believe means that we only have to disable irqs when
+ * doing a write lock.
+ *
+ * An ordinary spin lock 'region_lock' that protects the three
+ * lists in the region_hash, with the 'state', 'list' and
+ * 'bhs_delayed' fields of the regions. This is used from irq
+ * context, so all other uses will have to suspend local irqs.
+ *---------------------------------------------------------------*/
+struct mirror_set;
+struct region_hash {
+ struct mirror_set *ms;
+ sector_t region_size;
+
+ /* holds persistent region state */
+ struct dirty_log *log;
+
+ /* hash table */
+ rwlock_t hash_lock;
+ mempool_t *region_pool;
+ unsigned int mask;
+ unsigned int nr_buckets;
+ struct list_head *buckets;
+
+ spinlock_t region_lock;
+ struct semaphore recovery_count;
+ struct list_head clean_regions;
+ struct list_head quiesced_regions;
+ struct list_head recovered_regions;
+};
+
+enum {
+ RH_CLEAN,
+ RH_DIRTY,
+ RH_NOSYNC,
+ RH_RECOVERING
+};
+
+struct region {
+ struct region_hash *rh; /* FIXME: can we get rid of this ? */
+ region_t key;
+ int state;
+
+ struct list_head hash_list;
+ struct list_head list;
+
+ atomic_t pending;
+ struct buffer_head *delayed_bhs;
+};
+
+/*
+ * Conversion fns
+ */
+static inline region_t bh_to_region(struct region_hash *rh,
+ struct buffer_head *bh)
+{
+ return bh->b_rsector / rh->region_size;
+}
+
+static inline sector_t region_to_sector(struct region_hash *rh, region_t region)
+{
+ return region * rh->region_size;
+}
+
+/* FIXME move this */
+static void queue_bh(struct mirror_set *ms, struct buffer_head *bh, int rw);
+
+static void *region_alloc(int gfp_mask, void *pool_data)
+{
+ return kmalloc(sizeof(struct region), gfp_mask);
+}
+
+static void region_free(void *element, void *pool_data)
+{
+ kfree(element);
+}
+
+#define MIN_REGIONS 64
+#define MAX_RECOVERY 1
+static int rh_init(struct region_hash *rh, struct mirror_set *ms,
+ struct dirty_log *log, sector_t region_size,
+ region_t nr_regions)
+{
+ unsigned int nr_buckets, max_buckets;
+ size_t i;
+
+ /*
+ * Calculate a suitable number of buckets for our hash
+ * table.
+ */
+ max_buckets = nr_regions >> 6;
+ for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1)
+ ;
+ nr_buckets >>= 1;
+
+ rh->ms = ms;
+ rh->log = log;
+ rh->region_size = region_size;
+ rwlock_init(&rh->hash_lock);
+ rh->mask = nr_buckets - 1;
+ rh->nr_buckets = nr_buckets;
+
+ rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets));
+ if (!rh->buckets) {
+ DMERR("unable to allocate region hash memory");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < nr_buckets; i++)
+ INIT_LIST_HEAD(rh->buckets + i);
+
+ spin_lock_init(&rh->region_lock);
+ sema_init(&rh->recovery_count, 0);
+ INIT_LIST_HEAD(&rh->clean_regions);
+ INIT_LIST_HEAD(&rh->quiesced_regions);
+ INIT_LIST_HEAD(&rh->recovered_regions);
+
+ rh->region_pool = mempool_create(MIN_REGIONS, region_alloc,
+ region_free, NULL);
+ if (!rh->region_pool) {
+ vfree(rh->buckets);
+ rh->buckets = NULL;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void rh_exit(struct region_hash *rh)
+{
+ unsigned int h;
+ struct region *reg;
+ struct list_head *tmp, *tmp2;
+
+ BUG_ON(!list_empty(&rh->quiesced_regions));
+ for (h = 0; h < rh->nr_buckets; h++) {
+ list_for_each_safe (tmp, tmp2, rh->buckets + h) {
+ reg = list_entry(tmp, struct region, hash_list);
+ BUG_ON(atomic_read(®->pending));
+ mempool_free(reg, rh->region_pool);
+ }
+ }
+
+ if (rh->log)
+ dm_destroy_dirty_log(rh->log);
+ if (rh->region_pool)
+ mempool_destroy(rh->region_pool);
+ vfree(rh->buckets);
+}
+
+#define RH_HASH_MULT 2654435387U
+
+static inline unsigned int rh_hash(struct region_hash *rh, region_t region)
+{
+ return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask;
+}
+
+static struct region *__rh_lookup(struct region_hash *rh, region_t region)
+{
+ struct region *reg;
+
+ list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list)
+ if (reg->key == region)
+ return reg;
+
+ return NULL;
+}
+
+static void __rh_insert(struct region_hash *rh, struct region *reg)
+{
+ unsigned int h = rh_hash(rh, reg->key);
+ list_add(®->hash_list, rh->buckets + h);
+}
+
+static struct region *__rh_alloc(struct region_hash *rh, region_t region)
+{
+ struct region *reg, *nreg;
+
+ read_unlock(&rh->hash_lock);
+ nreg = mempool_alloc(rh->region_pool, GFP_NOIO);
+ nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
+ RH_CLEAN : RH_NOSYNC;
+ nreg->rh = rh;
+ nreg->key = region;
+
+ INIT_LIST_HEAD(&nreg->list);
+
+ atomic_set(&nreg->pending, 0);
+ nreg->delayed_bhs = NULL;
+ write_lock_irq(&rh->hash_lock);
+
+ reg = __rh_lookup(rh, region);
+ if (reg)
+ /* we lost the race */
+ mempool_free(nreg, rh->region_pool);
+
+ else {
+ __rh_insert(rh, nreg);
+ if (nreg->state == RH_CLEAN) {
+ spin_lock_irq(&rh->region_lock);
+ list_add(&nreg->list, &rh->clean_regions);
+ spin_unlock_irq(&rh->region_lock);
+ }
+ reg = nreg;
+ }
+ write_unlock_irq(&rh->hash_lock);
+ read_lock(&rh->hash_lock);
+
+ return reg;
+}
+
+static inline struct region *__rh_find(struct region_hash *rh, region_t region)
+{
+ struct region *reg;
+
+ reg = __rh_lookup(rh, region);
+ if (!reg)
+ reg = __rh_alloc(rh, region);
+
+ return reg;
+}
+
+static int rh_state(struct region_hash *rh, region_t region, int may_block)
+{
+ int r;
+ struct region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_lookup(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ if (reg)
+ return reg->state;
+
+ /*
+ * The region wasn't in the hash, so we fall back to the
+ * dirty log.
+ */
+ r = rh->log->type->in_sync(rh->log, region, may_block);
+
+ /*
+ * Any error from the dirty log (eg. -EWOULDBLOCK) gets
+ * taken as a RH_NOSYNC
+ */
+ return r == 1 ? RH_CLEAN : RH_NOSYNC;
+}
+
+static inline int rh_in_sync(struct region_hash *rh,
+ region_t region, int may_block)
+{
+ int state = rh_state(rh, region, may_block);
+ return state == RH_CLEAN || state == RH_DIRTY;
+}
+
+static void dispatch_buffers(struct mirror_set *ms, struct buffer_head *bh)
+{
+ struct buffer_head *nbh;
+
+ while (bh) {
+ nbh = bh->b_reqnext;
+ queue_bh(ms, bh, WRITE);
+ bh = nbh;
+ }
+}
+
+static void rh_update_states(struct region_hash *rh)
+{
+ struct list_head *tmp, *tmp2;
+ struct region *reg;
+
+ LIST_HEAD(clean);
+ LIST_HEAD(recovered);
+
+ /*
+ * Quickly grab the lists.
+ */
+ write_lock_irq(&rh->hash_lock);
+ spin_lock(&rh->region_lock);
+ if (!list_empty(&rh->clean_regions)) {
+ list_splice(&rh->clean_regions, &clean);
+ INIT_LIST_HEAD(&rh->clean_regions);
+
+ list_for_each_entry (reg, &clean, list) {
+ rh->log->type->clear_region(rh->log, reg->key);
+ list_del(®->hash_list);
+ }
+ }
+
+ if (!list_empty(&rh->recovered_regions)) {
+ list_splice(&rh->recovered_regions, &recovered);
+ INIT_LIST_HEAD(&rh->recovered_regions);
+
+ list_for_each_entry (reg, &recovered, list)
+ list_del(®->hash_list);
+ }
+ spin_unlock(&rh->region_lock);
+ write_unlock_irq(&rh->hash_lock);
+
+ /*
+ * All the regions on the recovered and clean lists have
+ * now been pulled out of the system, so no need to do
+ * any more locking.
+ */
+ list_for_each_safe (tmp, tmp2, &recovered) {
+ reg = list_entry(tmp, struct region, list);
+
+ rh->log->type->complete_resync_work(rh->log, reg->key, 1);
+ dispatch_buffers(rh->ms, reg->delayed_bhs);
+ up(&rh->recovery_count);
+ mempool_free(reg, rh->region_pool);
+ }
+
+ list_for_each_safe (tmp, tmp2, &clean) {
+ reg = list_entry(tmp, struct region, list);
+ mempool_free(reg, rh->region_pool);
+ }
+}
+
+static void rh_inc(struct region_hash *rh, region_t region)
+{
+ struct region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, region);
+ if (reg->state == RH_CLEAN) {
+ rh->log->type->mark_region(rh->log, reg->key);
+
+ spin_lock_irq(&rh->region_lock);
+ reg->state = RH_DIRTY;
+ list_del_init(®->list); /* take off the clean list */
+ spin_unlock_irq(&rh->region_lock);
+ }
+
+ atomic_inc(®->pending);
+ read_unlock(&rh->hash_lock);
+}
+
+static void rh_inc_pending(struct region_hash *rh, struct buffer_list *buffers)
+{
+ struct buffer_head *bh;
+
+ for (bh = buffers->head; bh; bh = bh->b_reqnext)
+ rh_inc(rh, bh_to_region(rh, bh));
+}
+
+static void rh_dec(struct region_hash *rh, region_t region)
+{
+ unsigned long flags;
+ struct region *reg;
+ int wake = 0;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_lookup(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ if (atomic_dec_and_test(®->pending)) {
+ spin_lock_irqsave(&rh->region_lock, flags);
+ if (reg->state == RH_RECOVERING) {
+ list_add_tail(®->list, &rh->quiesced_regions);
+ } else {
+ reg->state = RH_CLEAN;
+ list_add(®->list, &rh->clean_regions);
+ }
+ spin_unlock_irqrestore(&rh->region_lock, flags);
+ wake = 1;
+ }
+
+ if (wake)
+ dm_daemon_wake(&_kmirrord);
+}
+
+/*
+ * Starts quiescing a region in preparation for recovery.
+ */
+static int __rh_recovery_prepare(struct region_hash *rh)
+{
+ int r;
+ struct region *reg;
+ region_t region;
+
+ /*
+ * Ask the dirty log what's next.
+ */
+ r = rh->log->type->get_resync_work(rh->log, ®ion);
+ if (r <= 0)
+ return r;
+
+ /*
+ * Get this region, and start it quiescing by setting the
+ * recovering flag.
+ */
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ spin_lock_irq(&rh->region_lock);
+ reg->state = RH_RECOVERING;
+
+ /* Already quiesced ? */
+ if (atomic_read(®->pending))
+ list_del_init(®->list);
+
+ else {
+ list_del_init(®->list);
+ list_add(®->list, &rh->quiesced_regions);
+ }
+ spin_unlock_irq(&rh->region_lock);
+
+ return 1;
+}
+
+static void rh_recovery_prepare(struct region_hash *rh)
+{
+ while (!down_trylock(&rh->recovery_count))
+ if (__rh_recovery_prepare(rh) <= 0) {
+ up(&rh->recovery_count);
+ break;
+ }
+}
+
+/*
+ * Returns any quiesced regions.
+ */
+static struct region *rh_recovery_start(struct region_hash *rh)
+{
+ struct region *reg = NULL;
+
+ spin_lock_irq(&rh->region_lock);
+ if (!list_empty(&rh->quiesced_regions)) {
+ reg = list_entry(rh->quiesced_regions.next,
+ struct region, list);
+ list_del_init(®->list); /* remove from the quiesced list */
+ }
+ spin_unlock_irq(&rh->region_lock);
+
+ return reg;
+}
+
+/* FIXME: success ignored for now */
+static void rh_recovery_end(struct region *reg, int success)
+{
+ struct region_hash *rh = reg->rh;
+
+ spin_lock_irq(&rh->region_lock);
+ list_add(®->list, ®->rh->recovered_regions);
+ spin_unlock_irq(&rh->region_lock);
+
+ dm_daemon_wake(&_kmirrord);
+}
+
+static void rh_flush(struct region_hash *rh)
+{
+ rh->log->type->flush(rh->log);
+}
+
+static void rh_delay(struct region_hash *rh, struct buffer_head *bh)
+{
+ struct region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, bh_to_region(rh, bh));
+ bh->b_reqnext = reg->delayed_bhs;
+ reg->delayed_bhs = bh;
+ read_unlock(&rh->hash_lock);
+}
+
+static void rh_stop_recovery(struct region_hash *rh)
+{
+ int i;
+
+ /* wait for any recovering regions */
+ for (i = 0; i < MAX_RECOVERY; i++)
+ down(&rh->recovery_count);
+}
+
+static void rh_start_recovery(struct region_hash *rh)
+{
+ int i;
+
+ for (i = 0; i < MAX_RECOVERY; i++)
+ up(&rh->recovery_count);
+
+ dm_daemon_wake(&_kmirrord);
+}
+
+/*-----------------------------------------------------------------
+ * Mirror set structures.
+ *---------------------------------------------------------------*/
+struct mirror {
+ atomic_t error_count;
+ struct dm_dev *dev;
+ sector_t offset;
+};
+
+struct mirror_set {
+ struct dm_target *ti;
+ struct list_head list;
+ struct region_hash rh;
+ struct kcopyd_client *kcopyd_client;
+
+ spinlock_t lock; /* protects the next two lists */
+ struct buffer_list reads;
+ struct buffer_list writes;
+
+ /* recovery */
+ region_t nr_regions;
+ region_t sync_count;
+
+ unsigned int nr_mirrors;
+ struct mirror mirror[0];
+};
+
+/*
+ * Every mirror should look like this one.
+ */
+#define DEFAULT_MIRROR 0
+
+/*
+ * This is yucky. We squirrel the mirror_set struct away inside
+ * b_reqnext for write buffers. This is safe since the bh
+ * doesn't get submitted to the lower levels of block layer.
+ */
+static struct mirror_set *bh_get_ms(struct buffer_head *bh)
+{
+ return (struct mirror_set *) bh->b_reqnext;
+}
+
+static void bh_set_ms(struct buffer_head *bh, struct mirror_set *ms)
+{
+ bh->b_reqnext = (struct buffer_head *) ms;
+}
+
+/*-----------------------------------------------------------------
+ * Recovery.
+ *
+ * When a mirror is first activated we may find that some regions
+ * are in the no-sync state. We have to recover these by
+ * recopying from the default mirror to all the others.
+ *---------------------------------------------------------------*/
+static void recovery_complete(int read_err, unsigned int write_err,
+ void *context)
+{
+ struct region *reg = (struct region *) context;
+ struct mirror_set *ms = reg->rh->ms;
+
+ /* FIXME: better error handling */
+ rh_recovery_end(reg, read_err || write_err);
+ if (++ms->sync_count == ms->nr_regions)
+ /* the sync is complete */
+ dm_table_event(ms->ti->table);
+}
+
+static int recover(struct mirror_set *ms, struct region *reg)
+{
+ int r;
+ unsigned int i;
+ struct io_region from, to[ms->nr_mirrors - 1], *dest;
+ struct mirror *m;
+ unsigned int flags = 0;
+
+ /* fill in the source */
+ m = ms->mirror + DEFAULT_MIRROR;
+ from.dev = m->dev->dev;
+ from.sector = m->offset + region_to_sector(reg->rh, reg->key);
+ if (reg->key == (ms->nr_regions - 1)) {
+ /*
+ * The final region may be smaller than
+ * region_size.
+ */
+ from.count = ms->ti->len & (reg->rh->region_size - 1);
+ if (!from.count)
+ from.count = reg->rh->region_size;
+ } else
+ from.count = reg->rh->region_size;
+
+ /* fill in the destinations */
+ for (i = 1; i < ms->nr_mirrors; i++) {
+ m = ms->mirror + i;
+ dest = to + (i - 1);
+
+ dest->dev = m->dev->dev;
+ dest->sector = m->offset + region_to_sector(reg->rh, reg->key);
+ dest->count = from.count;
+ }
+
+ /* hand to kcopyd */
+ set_bit(KCOPYD_IGNORE_ERROR, &flags);
+ r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags,
+ recovery_complete, reg);
+
+ return r;
+}
+
+static void do_recovery(struct mirror_set *ms)
+{
+ int r;
+ struct region *reg;
+
+ /*
+ * Start quiescing some regions.
+ */
+ rh_recovery_prepare(&ms->rh);
+
+ /*
+ * Copy any already quiesced regions.
+ */
+ while ((reg = rh_recovery_start(&ms->rh))) {
+ r = recover(ms, reg);
+ if (r)
+ rh_recovery_end(reg, 0);
+ }
+}
+
+/*-----------------------------------------------------------------
+ * Reads
+ *---------------------------------------------------------------*/
+static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
+{
+ /* FIXME: add read balancing */
+ return ms->mirror + DEFAULT_MIRROR;
+}
+
+/*
+ * remap a buffer to a particular mirror.
+ */
+static void map_buffer(struct mirror_set *ms,
+ struct mirror *m, struct buffer_head *bh)
+{
+ bh->b_rdev = m->dev->dev;
+ bh->b_rsector = m->offset + (bh->b_rsector - ms->ti->begin);
+}
+
+static void do_reads(struct mirror_set *ms, struct buffer_list *reads)
+{
+ region_t region;
+ struct buffer_head *bh;
+ struct mirror *m;
+
+ while ((bh = buffer_list_pop(reads))) {
+ region = bh_to_region(&ms->rh, bh);
+
+ /*
+ * We can only read balance if the region is in sync.
+ */
+ if (rh_in_sync(&ms->rh, region, 0))
+ m = choose_mirror(ms, bh->b_rsector);
+ else
+ m = ms->mirror + DEFAULT_MIRROR;
+
+ map_buffer(ms, m, bh);
+ generic_make_request(READ, bh);
+ }
+}
+
+/*-----------------------------------------------------------------
+ * Writes.
+ *
+ * We do different things with the write io depending on the
+ * state of the region that it's in:
+ *
+ * SYNC: increment pending, use kcopyd to write to *all* mirrors
+ * RECOVERING: delay the io until recovery completes
+ * NOSYNC: increment pending, just write to the default mirror
+ *---------------------------------------------------------------*/
+static void write_callback(unsigned int error, void *context)
+{
+ unsigned int i;
+ int uptodate = 1;
+ struct buffer_head *bh = (struct buffer_head *) context;
+ struct mirror_set *ms;
+
+ ms = bh_get_ms(bh);
+ bh_set_ms(bh, NULL);
+
+ /*
+ * NOTE: We don't decrement the pending count here,
+ * instead it is done by the targets endio function.
+ * This way we handle both writes to SYNC and NOSYNC
+ * regions with the same code.
+ */
+
+ if (error) {
+ /*
+ * only error the io if all mirrors failed.
+ * FIXME: bogus
+ */
+ uptodate = 0;
+ for (i = 0; i < ms->nr_mirrors; i++)
+ if (!test_bit(i, &error)) {
+ uptodate = 1;
+ break;
+ }
+ }
+ bh->b_end_io(bh, uptodate);
+}
+
+static void do_write(struct mirror_set *ms, struct buffer_head *bh)
+{
+ unsigned int i;
+ struct io_region io[ms->nr_mirrors];
+ struct mirror *m;
+
+ for (i = 0; i < ms->nr_mirrors; i++) {
+ m = ms->mirror + i;
+
+ io[i].dev = m->dev->dev;
+ io[i].sector = m->offset + (bh->b_rsector - ms->ti->begin);
+ io[i].count = bh->b_size >> 9;
+ }
+
+ bh_set_ms(bh, ms);
+ dm_io_async(ms->nr_mirrors, io, WRITE, bh->b_page,
+ (unsigned int) bh->b_data & ~PAGE_MASK, write_callback, bh);
+}
+
+static void do_writes(struct mirror_set *ms, struct buffer_list *writes)
+{
+ int state;
+ struct buffer_head *bh;
+ struct buffer_list sync, nosync, recover, *this_list = NULL;
+
+ if (!writes->head)
+ return;
+
+ /*
+ * Classify each write.
+ */
+ buffer_list_init(&sync);
+ buffer_list_init(&nosync);
+ buffer_list_init(&recover);
+
+ while ((bh = buffer_list_pop(writes))) {
+ state = rh_state(&ms->rh, bh_to_region(&ms->rh, bh), 1);
+ switch (state) {
+ case RH_CLEAN:
+ case RH_DIRTY:
+ this_list = &sync;
+ break;
+
+ case RH_NOSYNC:
+ this_list = &nosync;
+ break;
+
+ case RH_RECOVERING:
+ this_list = &recover;
+ break;
+ }
+
+ buffer_list_add(this_list, bh);
+ }
+
+ /*
+ * Increment the pending counts for any regions that will
+ * be written to (writes to recover regions are going to
+ * be delayed).
+ */
+ rh_inc_pending(&ms->rh, &sync);
+ rh_inc_pending(&ms->rh, &nosync);
+ rh_flush(&ms->rh);
+
+ /*
+ * Dispatch io.
+ */
+ while ((bh = buffer_list_pop(&sync)))
+ do_write(ms, bh);
+
+ while ((bh = buffer_list_pop(&recover)))
+ rh_delay(&ms->rh, bh);
+
+ while ((bh = buffer_list_pop(&nosync))) {
+ map_buffer(ms, ms->mirror + DEFAULT_MIRROR, bh);
+ generic_make_request(WRITE, bh);
+ }
+}
+
+/*-----------------------------------------------------------------
+ * kmirrord
+ *---------------------------------------------------------------*/
+static LIST_HEAD(_mirror_sets);
+static DECLARE_RWSEM(_mirror_sets_lock);
+
+static void do_mirror(struct mirror_set *ms)
+{
+ struct buffer_list reads, writes;
+
+ spin_lock(&ms->lock);
+ memcpy(&reads, &ms->reads, sizeof(reads));
+ buffer_list_init(&ms->reads);
+ memcpy(&writes, &ms->writes, sizeof(writes));
+ buffer_list_init(&ms->writes);
+ spin_unlock(&ms->lock);
+
+ rh_update_states(&ms->rh);
+ do_recovery(ms);
+ do_reads(ms, &reads);
+ do_writes(ms, &writes);
+ run_task_queue(&tq_disk);
+}
+
+static void do_work(void)
+{
+ struct mirror_set *ms;
+
+ down_read(&_mirror_sets_lock);
+ list_for_each_entry (ms, &_mirror_sets, list)
+ do_mirror(ms);
+ up_read(&_mirror_sets_lock);
+}
+
+/*-----------------------------------------------------------------
+ * Target functions
+ *---------------------------------------------------------------*/
+static struct mirror_set *alloc_context(unsigned int nr_mirrors,
+ sector_t region_size,
+ struct dm_target *ti,
+ struct dirty_log *dl)
+{
+ size_t len;
+ struct mirror_set *ms = NULL;
+
+ if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors))
+ return NULL;
+
+ len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
+
+ ms = kmalloc(len, GFP_KERNEL);
+ if (!ms) {
+ ti->error = "dm-mirror: Cannot allocate mirror context";
+ return NULL;
+ }
+
+ memset(ms, 0, len);
+ spin_lock_init(&ms->lock);
+
+ ms->ti = ti;
+ ms->nr_mirrors = nr_mirrors;
+ ms->nr_regions = dm_div_up(ti->len, region_size);
+
+ if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
+ ti->error = "dm-mirror: Error creating dirty region hash";
+ kfree(ms);
+ return NULL;
+ }
+
+ return ms;
+}
+
+static void free_context(struct mirror_set *ms, struct dm_target *ti,
+ unsigned int m)
+{
+ while (m--)
+ dm_put_device(ti, ms->mirror[m].dev);
+
+ rh_exit(&ms->rh);
+ kfree(ms);
+}
+
+static inline int _check_region_size(struct dm_target *ti, sector_t size)
+{
+ return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) ||
+ size > ti->len);
+}
+
+static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
+ unsigned int mirror, char **argv)
+{
+ sector_t offset;
+
+ if (sscanf(argv[1], SECTOR_FORMAT, &offset) != 1) {
+ ti->error = "dm-mirror: Invalid offset";
+ return -EINVAL;
+ }
+
+ if (dm_get_device(ti, argv[0], offset, ti->len,
+ dm_table_get_mode(ti->table),
+ &ms->mirror[mirror].dev)) {
+ ti->error = "dm-mirror: Device lookup failure";
+ return -ENXIO;
+ }
+
+ ms->mirror[mirror].offset = offset;
+
+ return 0;
+}
+
+static int add_mirror_set(struct mirror_set *ms)
+{
+ down_write(&_mirror_sets_lock);
+ list_add_tail(&ms->list, &_mirror_sets);
+ up_write(&_mirror_sets_lock);
+ dm_daemon_wake(&_kmirrord);
+
+ return 0;
+}
+
+static void del_mirror_set(struct mirror_set *ms)
+{
+ down_write(&_mirror_sets_lock);
+ list_del(&ms->list);
+ up_write(&_mirror_sets_lock);
+}
+
+/*
+ * Create dirty log: log_type #log_params <log_params>
+ */
+static struct dirty_log *create_dirty_log(struct dm_target *ti,
+ unsigned int argc, char **argv,
+ unsigned int *args_used)
+{
+ unsigned int param_count;
+ struct dirty_log *dl;
+
+ if (argc < 2) {
+ ti->error = "dm-mirror: Insufficient mirror log arguments";
+ return NULL;
+ }
+
+ if (sscanf(argv[1], "%u", ¶m_count) != 1 || param_count != 1) {
+ ti->error = "dm-mirror: Invalid mirror log argument count";
+ return NULL;
+ }
+
+ *args_used = 2 + param_count;
+
+ if (argc < *args_used) {
+ ti->error = "dm-mirror: Insufficient mirror log arguments";
+ return NULL;
+ }
+
+ dl = dm_create_dirty_log(argv[0], ti->len, param_count, argv + 2);
+ if (!dl) {
+ ti->error = "dm-mirror: Error creating mirror dirty log";
+ return NULL;
+ }
+
+ if (!_check_region_size(ti, dl->type->get_region_size(dl))) {
+ ti->error = "dm-mirror: Invalid region size";
+ dm_destroy_dirty_log(dl);
+ return NULL;
+ }
+
+ return dl;
+}
+
+/*
+ * Construct a mirror mapping:
+ *
+ * log_type #log_params <log_params>
+ * #mirrors [mirror_path offset]{2,}
+ *
+ * For now, #log_params = 1, log_type = "core"
+ *
+ */
+#define DM_IO_PAGES 64
+static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ int r;
+ unsigned int nr_mirrors, m, args_used;
+ struct mirror_set *ms;
+ struct dirty_log *dl;
+
+ dl = create_dirty_log(ti, argc, argv, &args_used);
+ if (!dl)
+ return -EINVAL;
+
+ argv += args_used;
+ argc -= args_used;
+
+ if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
+ nr_mirrors < 2) {
+ ti->error = "dm-mirror: Invalid number of mirrors";
+ dm_destroy_dirty_log(dl);
+ return -EINVAL;
+ }
+
+ argv++, argc--;
+
+ if (argc != nr_mirrors * 2) {
+ ti->error = "dm-mirror: Wrong number of mirror arguments";
+ dm_destroy_dirty_log(dl);
+ return -EINVAL;
+ }
+
+ ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
+ if (!ms) {
+ dm_destroy_dirty_log(dl);
+ return -ENOMEM;
+ }
+
+ /* Get the mirror parameter sets */
+ for (m = 0; m < nr_mirrors; m++) {
+ r = get_mirror(ms, ti, m, argv);
+ if (r) {
+ free_context(ms, ti, m);
+ return r;
+ }
+ argv += 2;
+ argc -= 2;
+ }
+
+ ti->private = ms;
+
+ r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
+ if (r) {
+ free_context(ms, ti, ms->nr_mirrors);
+ return r;
+ }
+
+ add_mirror_set(ms);
+ return 0;
+}
+
+static void mirror_dtr(struct dm_target *ti)
+{
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+
+ del_mirror_set(ms);
+ kcopyd_client_destroy(ms->kcopyd_client);
+ free_context(ms, ti, ms->nr_mirrors);
+}
+
+static void queue_bh(struct mirror_set *ms, struct buffer_head *bh, int rw)
+{
+ int wake = 0;
+ struct buffer_list *bl;
+
+ bl = (rw == WRITE) ? &ms->writes : &ms->reads;
+ spin_lock(&ms->lock);
+ wake = !(bl->head);
+ buffer_list_add(bl, bh);
+ spin_unlock(&ms->lock);
+
+ if (wake)
+ dm_daemon_wake(&_kmirrord);
+}
+
+/*
+ * Mirror mapping function
+ */
+static int mirror_map(struct dm_target *ti, struct buffer_head *bh,
+ int rw, union map_info *map_context)
+{
+ int r;
+ struct mirror *m;
+ struct mirror_set *ms = ti->private;
+
+ /* FIXME: nasty hack, 32 bit sector_t only */
+ map_context->ll = bh->b_rsector / ms->rh.region_size;
+
+ if (rw == WRITE) {
+ queue_bh(ms, bh, rw);
+ return 0;
+ }
+
+ r = ms->rh.log->type->in_sync(ms->rh.log, bh_to_region(&ms->rh, bh), 0);
+ if (r < 0 && r != -EWOULDBLOCK)
+ return r;
+
+ if (r == -EWOULDBLOCK) /* FIXME: ugly */
+ r = 0;
+
+ /*
+ * We don't want to fast track a recovery just for a read
+ * ahead. So we just let it silently fail.
+ * FIXME: get rid of this.
+ */
+ if (!r && rw == READA)
+ return -EIO;
+
+ if (!r) {
+ /* Pass this io over to the daemon */
+ queue_bh(ms, bh, rw);
+ return 0;
+ }
+
+ m = choose_mirror(ms, bh->b_rsector);
+ if (!m)
+ return -EIO;
+
+ map_buffer(ms, m, bh);
+ return 1;
+}
+
+static int mirror_end_io(struct dm_target *ti, struct buffer_head *bh,
+ int rw, int error, union map_info *map_context)
+{
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+ region_t region = map_context->ll;
+
+ /*
+ * We need to dec pending if this was a write.
+ */
+ if (rw == WRITE)
+ rh_dec(&ms->rh, region);
+
+ return 0;
+}
+
+static void mirror_suspend(struct dm_target *ti)
+{
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+ rh_stop_recovery(&ms->rh);
+}
+
+static void mirror_resume(struct dm_target *ti)
+{
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+ rh_start_recovery(&ms->rh);
+}
+
+static int mirror_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ unsigned int m, sz = 0;
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ sz += snprintf(result + sz, maxlen - sz, "%d ", ms->nr_mirrors);
+
+ for (m = 0; m < ms->nr_mirrors; m++)
+ sz += snprintf(result + sz, maxlen - sz, "%s ",
+ dm_kdevname(ms->mirror[m].dev->dev));
+
+ sz += snprintf(result + sz, maxlen - sz, "%lu/%lu",
+ ms->sync_count, ms->nr_regions);
+ break;
+
+ case STATUSTYPE_TABLE:
+ sz += snprintf(result + sz, maxlen - sz,
+ "%s 1 " SECTOR_FORMAT " %d ",
+ ms->rh.log->type->name, ms->rh.region_size,
+ ms->nr_mirrors);
+
+ for (m = 0; m < ms->nr_mirrors; m++)
+ sz += snprintf(result + sz, maxlen - sz, "%s %ld ",
+ dm_kdevname(ms->mirror[m].dev->dev),
+ ms->mirror[m].offset);
+ }
+
+ return 0;
+}
+
+static struct target_type mirror_target = {
+ .name = "mirror",
+ .version = {1, 0, 1},
+ .module = THIS_MODULE,
+ .ctr = mirror_ctr,
+ .dtr = mirror_dtr,
+ .map = mirror_map,
+ .end_io = mirror_end_io,
+ .suspend = mirror_suspend,
+ .resume = mirror_resume,
+ .status = mirror_status,
+};
+
+static int __init dm_mirror_init(void)
+{
+ int r;
+
+ r = dm_dirty_log_init();
+ if (r)
+ return r;
+
+ r = dm_daemon_start(&_kmirrord, "kmirrord", do_work);
+ if (r) {
+ DMERR("couldn't start kmirrord");
+ dm_dirty_log_exit();
+ return r;
+ }
+
+ r = dm_register_target(&mirror_target);
+ if (r < 0) {
+ DMERR("%s: Failed to register mirror target",
+ mirror_target.name);
+ dm_dirty_log_exit();
+ dm_daemon_stop(&_kmirrord);
+ }
+
+ return r;
+}
+
+static void __exit dm_mirror_exit(void)
+{
+ int r;
+
+ r = dm_unregister_target(&mirror_target);
+ if (r < 0)
+ DMERR("%s: unregister failed %d", mirror_target.name, r);
+
+ dm_daemon_stop(&_kmirrord);
+ dm_dirty_log_exit();
+}
+
+/* Module hooks */
+module_init(dm_mirror_init);
+module_exit(dm_mirror_exit);
+
+MODULE_DESCRIPTION(DM_NAME " mirror target");
+MODULE_AUTHOR("Heinz Mauelshagen <mge@sistina.com>");
+MODULE_LICENSE("GPL");
--- linux-2.4.26-rc1/drivers/md/dm-snapshot.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-snapshot.c Wed Mar 31 13:52:03 2004
@@ -0,0 +1,1237 @@
+/*
+ * dm-snapshot.c
+ *
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/config.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/device-mapper.h>
+#include <linux/vmalloc.h>
+
+#include "dm-snapshot.h"
+#include "kcopyd.h"
+
+/*
+ * FIXME: Remove this before release.
+ */
+#if 0
+#define DMDEBUG(x...) DMWARN( ## x)
+#else
+#define DMDEBUG(x...)
+#endif
+
+/*
+ * The percentage increment we will wake up users at
+ */
+#define WAKE_UP_PERCENT 5
+
+/*
+ * kcopyd priority of snapshot operations
+ */
+#define SNAPSHOT_COPY_PRIORITY 2
+
+/*
+ * Each snapshot reserves this many pages for io
+ * FIXME: calculate this
+ */
+#define SNAPSHOT_PAGES 256
+
+struct pending_exception {
+ struct exception e;
+
+ /*
+ * Origin buffers waiting for this to complete are held
+ * in a list (using b_reqnext).
+ */
+ struct buffer_head *origin_bhs;
+ struct buffer_head *snapshot_bhs;
+
+ /*
+ * Other pending_exceptions that are processing this
+ * chunk. When this list is empty, we know we can
+ * complete the origins.
+ */
+ struct list_head siblings;
+
+ /* Pointer back to snapshot context */
+ struct dm_snapshot *snap;
+
+ /*
+ * 1 indicates the exception has already been sent to
+ * kcopyd.
+ */
+ int started;
+};
+
+/*
+ * Hash table mapping origin volumes to lists of snapshots and
+ * a lock to protect it
+ */
+static kmem_cache_t *exception_cache;
+static kmem_cache_t *pending_cache;
+static mempool_t *pending_pool;
+
+/*
+ * One of these per registered origin, held in the snapshot_origins hash
+ */
+struct origin {
+ /* The origin device */
+ kdev_t dev;
+
+ struct list_head hash_list;
+
+ /* List of snapshots for this origin */
+ struct list_head snapshots;
+};
+
+/*
+ * Size of the hash table for origin volumes. If we make this
+ * the size of the minors list then it should be nearly perfect
+ */
+#define ORIGIN_HASH_SIZE 256
+#define ORIGIN_MASK 0xFF
+static struct list_head *_origins;
+static struct rw_semaphore _origins_lock;
+
+static int init_origin_hash(void)
+{
+ int i;
+
+ _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head),
+ GFP_KERNEL);
+ if (!_origins) {
+ DMERR("Device mapper: Snapshot: unable to allocate memory");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < ORIGIN_HASH_SIZE; i++)
+ INIT_LIST_HEAD(_origins + i);
+ init_rwsem(&_origins_lock);
+
+ return 0;
+}
+
+static void exit_origin_hash(void)
+{
+ kfree(_origins);
+}
+
+static inline unsigned int origin_hash(kdev_t dev)
+{
+ return MINOR(dev) & ORIGIN_MASK;
+}
+
+static struct origin *__lookup_origin(kdev_t origin)
+{
+ struct list_head *slist;
+ struct list_head *ol;
+ struct origin *o;
+
+ ol = &_origins[origin_hash(origin)];
+ list_for_each(slist, ol) {
+ o = list_entry(slist, struct origin, hash_list);
+
+ if (o->dev == origin)
+ return o;
+ }
+
+ return NULL;
+}
+
+static void __insert_origin(struct origin *o)
+{
+ struct list_head *sl = &_origins[origin_hash(o->dev)];
+ list_add_tail(&o->hash_list, sl);
+}
+
+/*
+ * Make a note of the snapshot and its origin so we can look it
+ * up when the origin has a write on it.
+ */
+static int register_snapshot(struct dm_snapshot *snap)
+{
+ struct origin *o;
+ kdev_t dev = snap->origin->dev;
+
+ down_write(&_origins_lock);
+ o = __lookup_origin(dev);
+
+ if (!o) {
+ /* New origin */
+ o = kmalloc(sizeof(*o), GFP_KERNEL);
+ if (!o) {
+ up_write(&_origins_lock);
+ return -ENOMEM;
+ }
+
+ /* Initialise the struct */
+ INIT_LIST_HEAD(&o->snapshots);
+ o->dev = dev;
+
+ __insert_origin(o);
+ }
+
+ list_add_tail(&snap->list, &o->snapshots);
+
+ up_write(&_origins_lock);
+ return 0;
+}
+
+static void unregister_snapshot(struct dm_snapshot *s)
+{
+ struct origin *o;
+
+ down_write(&_origins_lock);
+ o = __lookup_origin(s->origin->dev);
+
+ list_del(&s->list);
+ if (list_empty(&o->snapshots)) {
+ list_del(&o->hash_list);
+ kfree(o);
+ }
+
+ up_write(&_origins_lock);
+}
+
+/*
+ * Implementation of the exception hash tables.
+ */
+static int init_exception_table(struct exception_table *et, uint32_t size)
+{
+ unsigned int i;
+
+ et->hash_mask = size - 1;
+ et->table = vcalloc(size, sizeof(struct list_head));
+ if (!et->table)
+ return -ENOMEM;
+
+ for (i = 0; i < size; i++)
+ INIT_LIST_HEAD(et->table + i);
+
+ return 0;
+}
+
+static void exit_exception_table(struct exception_table *et, kmem_cache_t *mem)
+{
+ struct list_head *slot, *entry, *temp;
+ struct exception *ex;
+ int i, size;
+
+ size = et->hash_mask + 1;
+ for (i = 0; i < size; i++) {
+ slot = et->table + i;
+
+ list_for_each_safe(entry, temp, slot) {
+ ex = list_entry(entry, struct exception, hash_list);
+ kmem_cache_free(mem, ex);
+ }
+ }
+
+ vfree(et->table);
+}
+
+/*
+ * FIXME: check how this hash fn is performing.
+ */
+static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk)
+{
+ return chunk & et->hash_mask;
+}
+
+static void insert_exception(struct exception_table *eh, struct exception *e)
+{
+ struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)];
+ list_add(&e->hash_list, l);
+}
+
+static inline void remove_exception(struct exception *e)
+{
+ list_del(&e->hash_list);
+}
+
+/*
+ * Return the exception data for a sector, or NULL if not
+ * remapped.
+ */
+static struct exception *lookup_exception(struct exception_table *et,
+ chunk_t chunk)
+{
+ struct list_head *slot, *el;
+ struct exception *e;
+
+ slot = &et->table[exception_hash(et, chunk)];
+ list_for_each(el, slot) {
+ e = list_entry(el, struct exception, hash_list);
+ if (e->old_chunk == chunk)
+ return e;
+ }
+
+ return NULL;
+}
+
+static inline struct exception *alloc_exception(void)
+{
+ struct exception *e;
+
+ e = kmem_cache_alloc(exception_cache, GFP_NOIO);
+ if (!e)
+ e = kmem_cache_alloc(exception_cache, GFP_ATOMIC);
+
+ return e;
+}
+
+static inline void free_exception(struct exception *e)
+{
+ kmem_cache_free(exception_cache, e);
+}
+
+static inline struct pending_exception *alloc_pending_exception(void)
+{
+ return mempool_alloc(pending_pool, GFP_NOIO);
+}
+
+static inline void free_pending_exception(struct pending_exception *pe)
+{
+ mempool_free(pe, pending_pool);
+}
+
+int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
+{
+ struct exception *e;
+
+ e = alloc_exception();
+ if (!e)
+ return -ENOMEM;
+
+ e->old_chunk = old;
+ e->new_chunk = new;
+ insert_exception(&s->complete, e);
+ return 0;
+}
+
+/*
+ * Hard coded magic.
+ */
+static int calc_max_buckets(void)
+{
+ unsigned long mem;
+
+ mem = num_physpages << PAGE_SHIFT;
+ mem /= 50;
+ mem /= sizeof(struct list_head);
+
+ return mem;
+}
+
+/*
+ * Rounds a number down to a power of 2.
+ */
+static inline uint32_t round_down(uint32_t n)
+{
+ while (n & (n - 1))
+ n &= (n - 1);
+ return n;
+}
+
+/*
+ * Allocate room for a suitable hash table.
+ */
+static int init_hash_tables(struct dm_snapshot *s)
+{
+ sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
+
+ /*
+ * Calculate based on the size of the original volume or
+ * the COW volume...
+ */
+ cow_dev_size = get_dev_size(s->cow->dev);
+ origin_dev_size = get_dev_size(s->origin->dev);
+ max_buckets = calc_max_buckets();
+
+ hash_size = min(origin_dev_size, cow_dev_size) / s->chunk_size;
+ hash_size = min(hash_size, max_buckets);
+
+ /* Round it down to a power of 2 */
+ hash_size = round_down(hash_size);
+ if (init_exception_table(&s->complete, hash_size))
+ return -ENOMEM;
+
+ /*
+ * Allocate hash table for in-flight exceptions
+ * Make this smaller than the real hash table
+ */
+ hash_size >>= 3;
+ if (!hash_size)
+ hash_size = 64;
+
+ if (init_exception_table(&s->pending, hash_size)) {
+ exit_exception_table(&s->complete, exception_cache);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/*
+ * Round a number up to the nearest 'size' boundary. size must
+ * be a power of 2.
+ */
+static inline ulong round_up(ulong n, ulong size)
+{
+ size--;
+ return (n + size) & ~size;
+}
+
+/*
+ * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
+ */
+static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct dm_snapshot *s;
+ unsigned long chunk_size;
+ int r = -EINVAL;
+ char persistent;
+ char *origin_path;
+ char *cow_path;
+ char *value;
+ int blocksize;
+
+ if (argc < 4) {
+ ti->error = "dm-snapshot: requires exactly 4 arguments";
+ r = -EINVAL;
+ goto bad1;
+ }
+
+ origin_path = argv[0];
+ cow_path = argv[1];
+ persistent = toupper(*argv[2]);
+
+ if (persistent != 'P' && persistent != 'N') {
+ ti->error = "Persistent flag is not P or N";
+ r = -EINVAL;
+ goto bad1;
+ }
+
+ chunk_size = simple_strtoul(argv[3], &value, 10);
+ if (chunk_size == 0 || value == NULL) {
+ ti->error = "Invalid chunk size";
+ r = -EINVAL;
+ goto bad1;
+ }
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (s == NULL) {
+ ti->error = "Cannot allocate snapshot context private "
+ "structure";
+ r = -ENOMEM;
+ goto bad1;
+ }
+
+ r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin);
+ if (r) {
+ ti->error = "Cannot get origin device";
+ goto bad2;
+ }
+
+ /* FIXME: get cow length */
+ r = dm_get_device(ti, cow_path, 0, 0,
+ FMODE_READ | FMODE_WRITE, &s->cow);
+ if (r) {
+ dm_put_device(ti, s->origin);
+ ti->error = "Cannot get COW device";
+ goto bad2;
+ }
+
+ /*
+ * Chunk size must be multiple of page size. Silently
+ * round up if it's not.
+ */
+ chunk_size = round_up(chunk_size, PAGE_SIZE / SECTOR_SIZE);
+
+ /* Validate the chunk size against the device block size */
+ blocksize = get_hardsect_size(s->cow->dev);
+ if (chunk_size % (blocksize / SECTOR_SIZE)) {
+ ti->error = "Chunk size is not a multiple of device blocksize";
+ r = -EINVAL;
+ goto bad3;
+ }
+
+ /* Check the sizes are small enough to fit in one kiovec */
+ if (chunk_size > KIO_MAX_SECTORS) {
+ ti->error = "Chunk size is too big";
+ r = -EINVAL;
+ goto bad3;
+ }
+
+ /* Check chunk_size is a power of 2 */
+ if (chunk_size & (chunk_size - 1)) {
+ ti->error = "Chunk size is not a power of 2";
+ r = -EINVAL;
+ goto bad3;
+ }
+
+ s->chunk_size = chunk_size;
+ s->chunk_mask = chunk_size - 1;
+ s->type = persistent;
+ for (s->chunk_shift = 0; chunk_size;
+ s->chunk_shift++, chunk_size >>= 1)
+ ;
+ s->chunk_shift--;
+
+ s->valid = 1;
+ s->have_metadata = 0;
+ s->last_percent = 0;
+ init_rwsem(&s->lock);
+ s->table = ti->table;
+
+ /* Allocate hash table for COW data */
+ if (init_hash_tables(s)) {
+ ti->error = "Unable to allocate hash table space";
+ r = -ENOMEM;
+ goto bad3;
+ }
+
+ /*
+ * Check the persistent flag - done here because we need the iobuf
+ * to check the LV header
+ */
+ s->store.snap = s;
+
+ if (persistent == 'P')
+ r = dm_create_persistent(&s->store, s->chunk_size);
+ else
+ r = dm_create_transient(&s->store, s, blocksize);
+
+ if (r) {
+ ti->error = "Couldn't create exception store";
+ r = -EINVAL;
+ goto bad4;
+ }
+
+ r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
+ if (r) {
+ ti->error = "Could not create kcopyd client";
+ goto bad5;
+ }
+
+ /* Flush IO to the origin device */
+ fsync_dev(s->origin->dev);
+
+ /* Add snapshot to the list of snapshots for this origin */
+ if (register_snapshot(s)) {
+ r = -EINVAL;
+ ti->error = "Cannot register snapshot origin";
+ goto bad6;
+ }
+
+ ti->private = s;
+ return 0;
+
+ bad6:
+ kcopyd_client_destroy(s->kcopyd_client);
+
+ bad5:
+ s->store.destroy(&s->store);
+
+ bad4:
+ exit_exception_table(&s->pending, pending_cache);
+ exit_exception_table(&s->complete, exception_cache);
+
+ bad3:
+ dm_put_device(ti, s->cow);
+ dm_put_device(ti, s->origin);
+
+ bad2:
+ kfree(s);
+
+ bad1:
+ return r;
+}
+
+static void snapshot_dtr(struct dm_target *ti)
+{
+ struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
+
+ dm_table_event(ti->table);
+
+ unregister_snapshot(s);
+
+ exit_exception_table(&s->pending, pending_cache);
+ exit_exception_table(&s->complete, exception_cache);
+
+ /* Deallocate memory used */
+ s->store.destroy(&s->store);
+
+ dm_put_device(ti, s->origin);
+ dm_put_device(ti, s->cow);
+ kcopyd_client_destroy(s->kcopyd_client);
+ kfree(s);
+}
+
+/*
+ * We hold lists of buffer_heads, using the b_reqnext field.
+ */
+static void queue_buffer(struct buffer_head **queue, struct buffer_head *bh)
+{
+ bh->b_reqnext = *queue;
+ *queue = bh;
+}
+
+/*
+ * FIXME: inefficient.
+ */
+static void queue_buffers(struct buffer_head **queue, struct buffer_head *bhs)
+{
+ while (*queue)
+ queue = &((*queue)->b_reqnext);
+
+ *queue = bhs;
+}
+
+/*
+ * Flush a list of buffers.
+ */
+static void flush_buffers(struct buffer_head *bh)
+{
+ struct buffer_head *n;
+
+ DMDEBUG("begin flush");
+ while (bh) {
+ n = bh->b_reqnext;
+ bh->b_reqnext = NULL;
+ DMDEBUG("flushing %p", bh);
+ generic_make_request(WRITE, bh);
+ bh = n;
+ }
+
+ run_task_queue(&tq_disk);
+}
+
+/*
+ * Error a list of buffers.
+ */
+static void error_buffers(struct buffer_head *bh)
+{
+ struct buffer_head *n;
+
+ while (bh) {
+ n = bh->b_reqnext;
+ bh->b_reqnext = NULL;
+ buffer_IO_error(bh);
+ bh = n;
+ }
+}
+
+static struct buffer_head *__flush_bhs(struct pending_exception *pe)
+{
+ struct pending_exception *sibling;
+
+ if (list_empty(&pe->siblings))
+ return pe->origin_bhs;
+
+ sibling = list_entry(pe->siblings.next,
+ struct pending_exception, siblings);
+
+ list_del(&pe->siblings);
+
+ /* FIXME: I think there's a race on SMP machines here, add spin lock */
+ queue_buffers(&sibling->origin_bhs, pe->origin_bhs);
+
+ return NULL;
+}
+
+static void pending_complete(struct pending_exception *pe, int success)
+{
+ struct exception *e;
+ struct dm_snapshot *s = pe->snap;
+ struct buffer_head *flush = NULL;
+
+ if (success) {
+ e = alloc_exception();
+ if (!e) {
+ DMWARN("Unable to allocate exception.");
+ down_write(&s->lock);
+ s->store.drop_snapshot(&s->store);
+ s->valid = 0;
+ flush = __flush_bhs(pe);
+ up_write(&s->lock);
+
+ error_buffers(pe->snapshot_bhs);
+ goto out;
+ }
+
+ /*
+ * Add a proper exception, and remove the
+ * in-flight exception from the list.
+ */
+ down_write(&s->lock);
+
+ memcpy(e, &pe->e, sizeof(*e));
+ insert_exception(&s->complete, e);
+ remove_exception(&pe->e);
+ flush = __flush_bhs(pe);
+
+ /* Submit any pending write BHs */
+ up_write(&s->lock);
+
+ flush_buffers(pe->snapshot_bhs);
+ DMDEBUG("Exception completed successfully.");
+
+ /* Notify any interested parties */
+ if (s->store.fraction_full) {
+ sector_t numerator, denominator;
+ int pc;
+
+ s->store.fraction_full(&s->store, &numerator,
+ &denominator);
+ pc = numerator * 100 / denominator;
+
+ if (pc >= s->last_percent + WAKE_UP_PERCENT) {
+ dm_table_event(s->table);
+ s->last_percent = pc - pc % WAKE_UP_PERCENT;
+ }
+ }
+
+ } else {
+ /* Read/write error - snapshot is unusable */
+ down_write(&s->lock);
+ if (s->valid)
+ DMERR("Error reading/writing snapshot");
+ s->store.drop_snapshot(&s->store);
+ s->valid = 0;
+ remove_exception(&pe->e);
+ flush = __flush_bhs(pe);
+ up_write(&s->lock);
+
+ error_buffers(pe->snapshot_bhs);
+
+ dm_table_event(s->table);
+ DMDEBUG("Exception failed.");
+ }
+
+ out:
+ if (flush)
+ flush_buffers(flush);
+
+ free_pending_exception(pe);
+}
+
+static void commit_callback(void *context, int success)
+{
+ struct pending_exception *pe = (struct pending_exception *) context;
+ pending_complete(pe, success);
+}
+
+/*
+ * Called when the copy I/O has finished. kcopyd actually runs
+ * this code so don't block.
+ */
+static void copy_callback(int read_err, unsigned int write_err, void *context)
+{
+ struct pending_exception *pe = (struct pending_exception *) context;
+ struct dm_snapshot *s = pe->snap;
+
+ if (read_err || write_err)
+ pending_complete(pe, 0);
+
+ else
+ /* Update the metadata if we are persistent */
+ s->store.commit_exception(&s->store, &pe->e, commit_callback,
+ pe);
+}
+
+/*
+ * Dispatches the copy operation to kcopyd.
+ */
+static inline void start_copy(struct pending_exception *pe)
+{
+ struct dm_snapshot *s = pe->snap;
+ struct io_region src, dest;
+ kdev_t dev = s->origin->dev;
+ int *sizes = blk_size[major(dev)];
+ sector_t dev_size = (sector_t) -1;
+
+ if (pe->started)
+ return;
+
+ /* this is protected by snap->lock */
+ pe->started = 1;
+
+ if (sizes && sizes[minor(dev)])
+ dev_size = sizes[minor(dev)] << 1;
+
+ src.dev = dev;
+ src.sector = chunk_to_sector(s, pe->e.old_chunk);
+ src.count = min(s->chunk_size, dev_size - src.sector);
+
+ dest.dev = s->cow->dev;
+ dest.sector = chunk_to_sector(s, pe->e.new_chunk);
+ dest.count = src.count;
+
+ /* Hand over to kcopyd */
+ kcopyd_copy(s->kcopyd_client,
+ &src, 1, &dest, 0, copy_callback, pe);
+}
+
+/*
+ * Looks to see if this snapshot already has a pending exception
+ * for this chunk, otherwise it allocates a new one and inserts
+ * it into the pending table.
+ */
+static struct pending_exception *find_pending_exception(struct dm_snapshot *s,
+ struct buffer_head *bh)
+{
+ struct exception *e;
+ struct pending_exception *pe;
+ chunk_t chunk = sector_to_chunk(s, bh->b_rsector);
+
+ /*
+ * Is there a pending exception for this already ?
+ */
+ e = lookup_exception(&s->pending, chunk);
+ if (e) {
+ /* cast the exception to a pending exception */
+ pe = list_entry(e, struct pending_exception, e);
+
+ } else {
+ /* Create a new pending exception */
+ pe = alloc_pending_exception();
+ pe->e.old_chunk = chunk;
+ pe->origin_bhs = pe->snapshot_bhs = NULL;
+ INIT_LIST_HEAD(&pe->siblings);
+ pe->snap = s;
+ pe->started = 0;
+
+ if (s->store.prepare_exception(&s->store, &pe->e)) {
+ free_pending_exception(pe);
+ s->valid = 0;
+ return NULL;
+ }
+
+ insert_exception(&s->pending, &pe->e);
+ }
+
+ return pe;
+}
+
+static inline void remap_exception(struct dm_snapshot *s, struct exception *e,
+ struct buffer_head *bh)
+{
+ bh->b_rdev = s->cow->dev;
+ bh->b_rsector = chunk_to_sector(s, e->new_chunk) +
+ (bh->b_rsector & s->chunk_mask);
+}
+
+static int snapshot_map(struct dm_target *ti, struct buffer_head *bh, int rw,
+ union map_info *map_context)
+{
+ struct exception *e;
+ struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
+ int r = 1;
+ chunk_t chunk;
+ struct pending_exception *pe;
+
+ chunk = sector_to_chunk(s, bh->b_rsector);
+
+ /* Full snapshots are not usable */
+ if (!s->valid)
+ return -1;
+
+ /*
+ * Write to snapshot - higher level takes care of RW/RO
+ * flags so we should only get this if we are
+ * writeable.
+ */
+ if (rw == WRITE) {
+
+ down_write(&s->lock);
+
+ /* If the block is already remapped - use that, else remap it */
+ e = lookup_exception(&s->complete, chunk);
+ if (e)
+ remap_exception(s, e, bh);
+
+ else {
+ pe = find_pending_exception(s, bh);
+
+ if (!pe) {
+ s->store.drop_snapshot(&s->store);
+ s->valid = 0;
+ r = -EIO;
+ } else {
+ remap_exception(s, &pe->e, bh);
+ queue_buffer(&pe->snapshot_bhs, bh);
+ start_copy(pe);
+ r = 0;
+ }
+ }
+
+ up_write(&s->lock);
+
+ } else {
+ /*
+ * FIXME: this read path scares me because we
+ * always use the origin when we have a pending
+ * exception. However I can't think of a
+ * situation where this is wrong - ejt.
+ */
+
+ /* Do reads */
+ down_read(&s->lock);
+
+ /* See if it it has been remapped */
+ e = lookup_exception(&s->complete, chunk);
+ if (e)
+ remap_exception(s, e, bh);
+ else
+ bh->b_rdev = s->origin->dev;
+
+ up_read(&s->lock);
+ }
+
+ return r;
+}
+
+void snapshot_resume(struct dm_target *ti)
+{
+ struct dm_snapshot *s = (struct dm_snapshot *) ti->private;
+
+ if (s->have_metadata)
+ return;
+
+ if (s->store.read_metadata(&s->store)) {
+ down_write(&s->lock);
+ s->valid = 0;
+ up_write(&s->lock);
+ }
+
+ s->have_metadata = 1;
+}
+
+static int snapshot_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct dm_snapshot *snap = (struct dm_snapshot *) ti->private;
+ char cow[16];
+ char org[16];
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ if (!snap->valid)
+ snprintf(result, maxlen, "Invalid");
+ else {
+ if (snap->store.fraction_full) {
+ sector_t numerator, denominator;
+ snap->store.fraction_full(&snap->store,
+ &numerator,
+ &denominator);
+ snprintf(result, maxlen,
+ SECTOR_FORMAT "/" SECTOR_FORMAT,
+ numerator, denominator);
+ }
+ else
+ snprintf(result, maxlen, "Unknown");
+ }
+ break;
+
+ case STATUSTYPE_TABLE:
+ /*
+ * kdevname returns a static pointer so we need
+ * to make private copies if the output is to
+ * make sense.
+ */
+ strncpy(cow, dm_kdevname(snap->cow->dev), sizeof(cow));
+ strncpy(org, dm_kdevname(snap->origin->dev), sizeof(org));
+ snprintf(result, maxlen, "%s %s %c %ld", org, cow,
+ snap->type, snap->chunk_size);
+ break;
+ }
+
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * Origin methods
+ *---------------------------------------------------------------*/
+static void list_merge(struct list_head *l1, struct list_head *l2)
+{
+ struct list_head *l1_n, *l2_p;
+
+ l1_n = l1->next;
+ l2_p = l2->prev;
+
+ l1->next = l2;
+ l2->prev = l1;
+
+ l2_p->next = l1_n;
+ l1_n->prev = l2_p;
+}
+
+static int __origin_write(struct list_head *snapshots, struct buffer_head *bh)
+{
+ int r = 1, first = 1;
+ struct list_head *sl;
+ struct dm_snapshot *snap;
+ struct exception *e;
+ struct pending_exception *pe, *last = NULL;
+ chunk_t chunk;
+
+ /* Do all the snapshots on this origin */
+ list_for_each(sl, snapshots) {
+ snap = list_entry(sl, struct dm_snapshot, list);
+
+ /* Only deal with valid snapshots */
+ if (!snap->valid)
+ continue;
+
+ down_write(&snap->lock);
+
+ /*
+ * Remember, different snapshots can have
+ * different chunk sizes.
+ */
+ chunk = sector_to_chunk(snap, bh->b_rsector);
+
+ /*
+ * Check exception table to see if block
+ * is already remapped in this snapshot
+ * and trigger an exception if not.
+ */
+ e = lookup_exception(&snap->complete, chunk);
+ if (!e) {
+ pe = find_pending_exception(snap, bh);
+ if (!pe) {
+ snap->store.drop_snapshot(&snap->store);
+ snap->valid = 0;
+
+ } else {
+ if (last)
+ list_merge(&pe->siblings,
+ &last->siblings);
+
+ last = pe;
+ r = 0;
+ }
+ }
+
+ up_write(&snap->lock);
+ }
+
+ /*
+ * Now that we have a complete pe list we can start the copying.
+ */
+ if (last) {
+ pe = last;
+ do {
+ down_write(&pe->snap->lock);
+ if (first)
+ queue_buffer(&pe->origin_bhs, bh);
+ start_copy(pe);
+ up_write(&pe->snap->lock);
+ first = 0;
+ pe = list_entry(pe->siblings.next,
+ struct pending_exception, siblings);
+
+ } while (pe != last);
+ }
+
+ return r;
+}
+
+/*
+ * Called on a write from the origin driver.
+ */
+int do_origin(struct dm_dev *origin, struct buffer_head *bh)
+{
+ struct origin *o;
+ int r;
+
+ down_read(&_origins_lock);
+ o = __lookup_origin(origin->dev);
+ if (!o)
+ BUG();
+
+ r = __origin_write(&o->snapshots, bh);
+ up_read(&_origins_lock);
+
+ return r;
+}
+
+/*
+ * Origin: maps a linear range of a device, with hooks for snapshotting.
+ */
+
+/*
+ * Construct an origin mapping: <dev_path>
+ * The context for an origin is merely a 'struct dm_dev *'
+ * pointing to the real device.
+ */
+static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ int r;
+ struct dm_dev *dev;
+
+ if (argc != 1) {
+ ti->error = "dm-origin: incorrect number of arguments";
+ return -EINVAL;
+ }
+
+ r = dm_get_device(ti, argv[0], 0, ti->len,
+ dm_table_get_mode(ti->table), &dev);
+ if (r) {
+ ti->error = "Cannot get target device";
+ return r;
+ }
+
+ ti->private = dev;
+ return 0;
+}
+
+static void origin_dtr(struct dm_target *ti)
+{
+ struct dm_dev *dev = (struct dm_dev *) ti->private;
+ dm_put_device(ti, dev);
+}
+
+static int origin_map(struct dm_target *ti, struct buffer_head *bh, int rw,
+ union map_info *map_context)
+{
+ struct dm_dev *dev = (struct dm_dev *) ti->private;
+ bh->b_rdev = dev->dev;
+
+ /* Only tell snapshots if this is a write */
+ return (rw == WRITE) ? do_origin(dev, bh) : 1;
+}
+
+static int origin_status(struct dm_target *ti, status_type_t type, char *result,
+ unsigned int maxlen)
+{
+ struct dm_dev *dev = (struct dm_dev *) ti->private;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ snprintf(result, maxlen, "%s", dm_kdevname(dev->dev));
+ break;
+ }
+
+ return 0;
+}
+
+static struct target_type origin_target = {
+ name: "snapshot-origin",
+ version: {1, 0, 1},
+ module: THIS_MODULE,
+ ctr: origin_ctr,
+ dtr: origin_dtr,
+ map: origin_map,
+ status: origin_status,
+};
+
+static struct target_type snapshot_target = {
+ name: "snapshot",
+ version: {1, 0, 1},
+ module: THIS_MODULE,
+ ctr: snapshot_ctr,
+ dtr: snapshot_dtr,
+ map: snapshot_map,
+ resume: snapshot_resume,
+ status: snapshot_status,
+};
+
+int __init dm_snapshot_init(void)
+{
+ int r;
+
+ r = dm_register_target(&snapshot_target);
+ if (r) {
+ DMERR("snapshot target register failed %d", r);
+ return r;
+ }
+
+ r = dm_register_target(&origin_target);
+ if (r < 0) {
+ DMERR("Device mapper: Origin: register failed %d\n", r);
+ goto bad1;
+ }
+
+ r = init_origin_hash();
+ if (r) {
+ DMERR("init_origin_hash failed.");
+ goto bad2;
+ }
+
+ exception_cache = kmem_cache_create("dm-snapshot-ex",
+ sizeof(struct exception),
+ __alignof__(struct exception),
+ 0, NULL, NULL);
+ if (!exception_cache) {
+ DMERR("Couldn't create exception cache.");
+ r = -ENOMEM;
+ goto bad3;
+ }
+
+ pending_cache =
+ kmem_cache_create("dm-snapshot-in",
+ sizeof(struct pending_exception),
+ __alignof__(struct pending_exception),
+ 0, NULL, NULL);
+ if (!pending_cache) {
+ DMERR("Couldn't create pending cache.");
+ r = -ENOMEM;
+ goto bad4;
+ }
+
+ pending_pool = mempool_create(128, mempool_alloc_slab,
+ mempool_free_slab, pending_cache);
+ if (!pending_pool) {
+ DMERR("Couldn't create pending pool.");
+ r = -ENOMEM;
+ goto bad5;
+ }
+
+ return 0;
+
+ bad5:
+ kmem_cache_destroy(pending_cache);
+ bad4:
+ kmem_cache_destroy(exception_cache);
+ bad3:
+ exit_origin_hash();
+ bad2:
+ dm_unregister_target(&origin_target);
+ bad1:
+ dm_unregister_target(&snapshot_target);
+ return r;
+}
+
+void dm_snapshot_exit(void)
+{
+ int r;
+
+ r = dm_unregister_target(&snapshot_target);
+ if (r)
+ DMERR("snapshot unregister failed %d", r);
+
+ r = dm_unregister_target(&origin_target);
+ if (r)
+ DMERR("origin unregister failed %d", r);
+
+ exit_origin_hash();
+ mempool_destroy(pending_pool);
+ kmem_cache_destroy(pending_cache);
+ kmem_cache_destroy(exception_cache);
+}
--- linux-2.4.26-rc1/drivers/md/dm-snapshot.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-snapshot.h Wed Mar 31 13:48:32 2004
@@ -0,0 +1,158 @@
+/*
+ * dm-snapshot.c
+ *
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_SNAPSHOT_H
+#define DM_SNAPSHOT_H
+
+#include "dm.h"
+#include <linux/blkdev.h>
+
+struct exception_table {
+ uint32_t hash_mask;
+ struct list_head *table;
+};
+
+/*
+ * The snapshot code deals with largish chunks of the disk at a
+ * time. Typically 64k - 256k.
+ */
+/* FIXME: can we get away with limiting these to a uint32_t ? */
+typedef sector_t chunk_t;
+
+/*
+ * An exception is used where an old chunk of data has been
+ * replaced by a new one.
+ */
+struct exception {
+ struct list_head hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+/*
+ * Abstraction to handle the meta/layout of exception stores (the
+ * COW device).
+ */
+struct exception_store {
+
+ /*
+ * Destroys this object when you've finished with it.
+ */
+ void (*destroy) (struct exception_store *store);
+
+ /*
+ * The target shouldn't read the COW device until this is
+ * called.
+ */
+ int (*read_metadata) (struct exception_store *store);
+
+ /*
+ * Find somewhere to store the next exception.
+ */
+ int (*prepare_exception) (struct exception_store *store,
+ struct exception *e);
+
+ /*
+ * Update the metadata with this exception.
+ */
+ void (*commit_exception) (struct exception_store *store,
+ struct exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context);
+
+ /*
+ * The snapshot is invalid, note this in the metadata.
+ */
+ void (*drop_snapshot) (struct exception_store *store);
+
+ /*
+ * Return how full the snapshot is.
+ */
+ void (*fraction_full) (struct exception_store *store,
+ sector_t *numerator,
+ sector_t *denominator);
+
+ struct dm_snapshot *snap;
+ void *context;
+};
+
+struct dm_snapshot {
+ struct rw_semaphore lock;
+ struct dm_table *table;
+
+ struct dm_dev *origin;
+ struct dm_dev *cow;
+
+ /* List of snapshots per Origin */
+ struct list_head list;
+
+ /* Size of data blocks saved - must be a power of 2 */
+ chunk_t chunk_size;
+ chunk_t chunk_mask;
+ chunk_t chunk_shift;
+
+ /* You can't use a snapshot if this is 0 (e.g. if full) */
+ int valid;
+ int have_metadata;
+
+ /* Used for display of table */
+ char type;
+
+ /* The last percentage we notified */
+ int last_percent;
+
+ struct exception_table pending;
+ struct exception_table complete;
+
+ /* The on disk metadata handler */
+ struct exception_store store;
+
+ struct kcopyd_client *kcopyd_client;
+};
+
+/*
+ * Used by the exception stores to load exceptions hen
+ * initialising.
+ */
+int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
+
+/*
+ * Constructor and destructor for the default persistent
+ * store.
+ */
+int dm_create_persistent(struct exception_store *store, uint32_t chunk_size);
+
+int dm_create_transient(struct exception_store *store,
+ struct dm_snapshot *s, int blocksize);
+
+/*
+ * Return the number of sectors in the device.
+ */
+static inline sector_t get_dev_size(kdev_t dev)
+{
+ int *sizes;
+
+ sizes = blk_size[MAJOR(dev)];
+ if (sizes)
+ return sizes[MINOR(dev)] << 1;
+
+ return 0;
+}
+
+static inline chunk_t sector_to_chunk(struct dm_snapshot *s, sector_t sector)
+{
+ return (sector & ~s->chunk_mask) >> s->chunk_shift;
+}
+
+static inline sector_t chunk_to_sector(struct dm_snapshot *s, chunk_t chunk)
+{
+ return chunk << s->chunk_shift;
+}
+
+#endif
--- linux-2.4.26-rc1/drivers/md/dm-stripe.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-stripe.c Wed Mar 31 13:49:22 2004
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+
+struct stripe {
+ struct dm_dev *dev;
+ sector_t physical_start;
+};
+
+struct stripe_c {
+ uint32_t stripes;
+
+ /* The size of this target / num. stripes */
+ uint32_t stripe_width;
+
+ /* stripe chunk size */
+ uint32_t chunk_shift;
+ sector_t chunk_mask;
+
+ struct stripe stripe[0];
+};
+
+static inline struct stripe_c *alloc_context(unsigned int stripes)
+{
+ size_t len;
+
+ if (array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
+ stripes))
+ return NULL;
+
+ len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
+
+ return kmalloc(len, GFP_KERNEL);
+}
+
+/*
+ * Parse a single <dev> <sector> pair
+ */
+static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
+ unsigned int stripe, char **argv)
+{
+ sector_t start;
+
+ if (sscanf(argv[1], SECTOR_FORMAT, &start) != 1)
+ return -EINVAL;
+
+ if (dm_get_device(ti, argv[0], start, sc->stripe_width,
+ dm_table_get_mode(ti->table),
+ &sc->stripe[stripe].dev))
+ return -ENXIO;
+
+ sc->stripe[stripe].physical_start = start;
+ return 0;
+}
+
+/*
+ * FIXME: Nasty function, only present because we can't link
+ * against __moddi3 and __divdi3.
+ *
+ * returns a == b * n
+ */
+static int multiple(sector_t a, sector_t b, sector_t *n)
+{
+ sector_t acc, prev, i;
+
+ *n = 0;
+ while (a >= b) {
+ for (acc = b, prev = 0, i = 1;
+ acc <= a;
+ prev = acc, acc <<= 1, i <<= 1)
+ ;
+
+ a -= prev;
+ *n += i >> 1;
+ }
+
+ return a == 0;
+}
+
+/*
+ * Construct a striped mapping.
+ * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
+ */
+static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct stripe_c *sc;
+ sector_t width;
+ uint32_t stripes;
+ uint32_t chunk_size;
+ char *end;
+ int r;
+ unsigned int i;
+
+ if (argc < 2) {
+ ti->error = "dm-stripe: Not enough arguments";
+ return -EINVAL;
+ }
+
+ stripes = simple_strtoul(argv[0], &end, 10);
+ if (*end) {
+ ti->error = "dm-stripe: Invalid stripe count";
+ return -EINVAL;
+ }
+
+ chunk_size = simple_strtoul(argv[1], &end, 10);
+ if (*end) {
+ ti->error = "dm-stripe: Invalid chunk_size";
+ return -EINVAL;
+ }
+
+ /*
+ * chunk_size is a power of two
+ */
+ if (!chunk_size || (chunk_size & (chunk_size - 1))) {
+ ti->error = "dm-stripe: Invalid chunk size";
+ return -EINVAL;
+ }
+
+ if (!multiple(ti->len, stripes, &width)) {
+ ti->error = "dm-stripe: Target length not divisable by "
+ "number of stripes";
+ return -EINVAL;
+ }
+
+ /*
+ * Do we have enough arguments for that many stripes ?
+ */
+ if (argc != (2 + 2 * stripes)) {
+ ti->error = "dm-stripe: Not enough destinations specified";
+ return -EINVAL;
+ }
+
+ sc = alloc_context(stripes);
+ if (!sc) {
+ ti->error = "dm-stripe: Memory allocation for striped context "
+ "failed";
+ return -ENOMEM;
+ }
+
+ sc->stripes = stripes;
+ sc->stripe_width = width;
+
+ sc->chunk_mask = ((sector_t) chunk_size) - 1;
+ for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
+ chunk_size >>= 1;
+ sc->chunk_shift--;
+
+ /*
+ * Get the stripe destinations.
+ */
+ for (i = 0; i < stripes; i++) {
+ argv += 2;
+
+ r = get_stripe(ti, sc, i, argv);
+ if (r < 0) {
+ ti->error = "dm-stripe: Couldn't parse stripe "
+ "destination";
+ while (i--)
+ dm_put_device(ti, sc->stripe[i].dev);
+ kfree(sc);
+ return r;
+ }
+ }
+
+ ti->private = sc;
+ return 0;
+}
+
+static void stripe_dtr(struct dm_target *ti)
+{
+ unsigned int i;
+ struct stripe_c *sc = (struct stripe_c *) ti->private;
+
+ for (i = 0; i < sc->stripes; i++)
+ dm_put_device(ti, sc->stripe[i].dev);
+
+ kfree(sc);
+}
+
+static int stripe_map(struct dm_target *ti, struct buffer_head *bh, int rw,
+ union map_info *context)
+{
+ struct stripe_c *sc = (struct stripe_c *) ti->private;
+
+ sector_t offset = bh->b_rsector - ti->begin;
+ uint32_t chunk = (uint32_t) (offset >> sc->chunk_shift);
+ uint32_t stripe = chunk % sc->stripes; /* 32bit modulus */
+ chunk = chunk / sc->stripes;
+
+ bh->b_rdev = sc->stripe[stripe].dev->dev;
+ bh->b_rsector = sc->stripe[stripe].physical_start +
+ (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
+ return 1;
+}
+
+static int stripe_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct stripe_c *sc = (struct stripe_c *) ti->private;
+ int offset;
+ unsigned int i;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ offset = snprintf(result, maxlen, "%d " SECTOR_FORMAT,
+ sc->stripes, sc->chunk_mask + 1);
+ for (i = 0; i < sc->stripes; i++) {
+ offset +=
+ snprintf(result + offset, maxlen - offset,
+ " %s " SECTOR_FORMAT,
+ dm_kdevname(to_kdev_t(sc->stripe[i].dev->bdev->bd_dev)),
+ sc->stripe[i].physical_start);
+ }
+ break;
+ }
+ return 0;
+}
+
+static struct target_type stripe_target = {
+ .name = "striped",
+ .version= {1, 0, 1},
+ .module = THIS_MODULE,
+ .ctr = stripe_ctr,
+ .dtr = stripe_dtr,
+ .map = stripe_map,
+ .status = stripe_status,
+};
+
+int __init dm_stripe_init(void)
+{
+ int r;
+
+ r = dm_register_target(&stripe_target);
+ if (r < 0)
+ DMWARN("striped target registration failed");
+
+ return r;
+}
+
+void dm_stripe_exit(void)
+{
+ if (dm_unregister_target(&stripe_target))
+ DMWARN("striped target unregistration failed");
+
+ return;
+}
--- linux-2.4.26-rc1/drivers/md/dm-table.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-table.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,679 @@
+/*
+ * Copyright (C) 2001 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/blkdev.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <asm/atomic.h>
+
+#define MAX_DEPTH 16
+#define NODE_SIZE L1_CACHE_BYTES
+#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
+#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
+
+struct dm_table {
+ atomic_t holders;
+
+ /* btree table */
+ unsigned int depth;
+ unsigned int counts[MAX_DEPTH]; /* in nodes */
+ sector_t *index[MAX_DEPTH];
+
+ unsigned int num_targets;
+ unsigned int num_allocated;
+ sector_t *highs;
+ struct dm_target *targets;
+
+ /*
+ * Indicates the rw permissions for the new logical
+ * device. This should be a combination of FMODE_READ
+ * and FMODE_WRITE.
+ */
+ int mode;
+
+ /* a list of devices used by this table */
+ struct list_head devices;
+
+ /* events get handed up using this callback */
+ void (*event_fn)(void *);
+ void *event_context;
+};
+
+/*
+ * Similar to ceiling(log_size(n))
+ */
+static unsigned int int_log(unsigned long n, unsigned long base)
+{
+ int result = 0;
+
+ while (n > 1) {
+ n = dm_div_up(n, base);
+ result++;
+ }
+
+ return result;
+}
+
+/*
+ * Calculate the index of the child node of the n'th node k'th key.
+ */
+static inline unsigned int get_child(unsigned int n, unsigned int k)
+{
+ return (n * CHILDREN_PER_NODE) + k;
+}
+
+/*
+ * Return the n'th node of level l from table t.
+ */
+static inline sector_t *get_node(struct dm_table *t, unsigned int l,
+ unsigned int n)
+{
+ return t->index[l] + (n * KEYS_PER_NODE);
+}
+
+/*
+ * Return the highest key that you could lookup from the n'th
+ * node on level l of the btree.
+ */
+static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
+{
+ for (; l < t->depth - 1; l++)
+ n = get_child(n, CHILDREN_PER_NODE - 1);
+
+ if (n >= t->counts[l])
+ return (sector_t) - 1;
+
+ return get_node(t, l, n)[KEYS_PER_NODE - 1];
+}
+
+/*
+ * Fills in a level of the btree based on the highs of the level
+ * below it.
+ */
+static int setup_btree_index(unsigned int l, struct dm_table *t)
+{
+ unsigned int n, k;
+ sector_t *node;
+
+ for (n = 0U; n < t->counts[l]; n++) {
+ node = get_node(t, l, n);
+
+ for (k = 0U; k < KEYS_PER_NODE; k++)
+ node[k] = high(t, l + 1, get_child(n, k));
+ }
+
+ return 0;
+}
+
+
+
+int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
+{
+ struct dm_table *t = kmalloc(sizeof(*t), GFP_KERNEL);
+
+ if (!t)
+ return -ENOMEM;
+
+ memset(t, 0, sizeof(*t));
+ INIT_LIST_HEAD(&t->devices);
+ atomic_set(&t->holders, 1);
+
+ num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
+
+ /* Allocate both the target array and offset array at once. */
+ t->highs = (sector_t *) vcalloc(sizeof(struct dm_target) +
+ sizeof(sector_t), num_targets);
+ if (!t->highs) {
+ kfree(t);
+ return -ENOMEM;
+ }
+
+ memset(t->highs, -1, sizeof(*t->highs) * num_targets);
+
+ t->targets = (struct dm_target *) (t->highs + num_targets);
+ t->num_allocated = num_targets;
+ t->mode = mode;
+ *result = t;
+ return 0;
+}
+
+static void free_devices(struct list_head *devices)
+{
+ struct list_head *tmp, *next;
+
+ for (tmp = devices->next; tmp != devices; tmp = next) {
+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+ next = tmp->next;
+ kfree(dd);
+ }
+}
+
+void table_destroy(struct dm_table *t)
+{
+ unsigned int i;
+
+ /* free the indexes (see dm_table_complete) */
+ if (t->depth >= 2)
+ vfree(t->index[t->depth - 2]);
+
+ /* free the targets */
+ for (i = 0; i < t->num_targets; i++) {
+ struct dm_target *tgt = t->targets + i;
+
+ if (tgt->type->dtr)
+ tgt->type->dtr(tgt);
+
+ dm_put_target_type(tgt->type);
+ }
+
+ vfree(t->highs);
+
+ /* free the device list */
+ if (t->devices.next != &t->devices) {
+ DMWARN("devices still present during destroy: "
+ "dm_table_remove_device calls missing");
+
+ free_devices(&t->devices);
+ }
+
+ kfree(t);
+}
+
+void dm_table_get(struct dm_table *t)
+{
+ atomic_inc(&t->holders);
+}
+
+void dm_table_put(struct dm_table *t)
+{
+ if (atomic_dec_and_test(&t->holders))
+ table_destroy(t);
+}
+
+/*
+ * Convert a device path to a dev_t.
+ */
+static int lookup_device(const char *path, kdev_t *dev)
+{
+ int r;
+ struct nameidata nd;
+ struct inode *inode;
+
+ if (!path_init(path, LOOKUP_FOLLOW, &nd))
+ return 0;
+
+ if ((r = path_walk(path, &nd)))
+ goto out;
+
+ inode = nd.dentry->d_inode;
+ if (!inode) {
+ r = -ENOENT;
+ goto out;
+ }
+
+ if (!S_ISBLK(inode->i_mode)) {
+ r = -ENOTBLK;
+ goto out;
+ }
+
+ *dev = inode->i_rdev;
+
+ out:
+ path_release(&nd);
+ return r;
+}
+
+/*
+ * See if we've already got a device in the list.
+ */
+static struct dm_dev *find_device(struct list_head *l, kdev_t dev)
+{
+ struct list_head *tmp;
+
+ list_for_each(tmp, l) {
+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+ if (kdev_same(dd->dev, dev))
+ return dd;
+ }
+
+ return NULL;
+}
+
+/*
+ * Open a device so we can use it as a map destination.
+ */
+static int open_dev(struct dm_dev *dd)
+{
+ if (dd->bdev)
+ BUG();
+
+ dd->bdev = bdget(kdev_t_to_nr(dd->dev));
+ if (!dd->bdev)
+ return -ENOMEM;
+
+ return blkdev_get(dd->bdev, dd->mode, 0, BDEV_RAW);
+}
+
+/*
+ * Close a device that we've been using.
+ */
+static void close_dev(struct dm_dev *dd)
+{
+ if (!dd->bdev)
+ return;
+
+ blkdev_put(dd->bdev, BDEV_RAW);
+ dd->bdev = NULL;
+}
+
+/*
+ * If possible (ie. blk_size[major] is set), this checks an area
+ * of a destination device is valid.
+ */
+static int check_device_area(kdev_t dev, sector_t start, sector_t len)
+{
+ int *sizes;
+ sector_t dev_size;
+
+ if (!(sizes = blk_size[major(dev)]) || !(dev_size = sizes[minor(dev)]))
+ /* we don't know the device details,
+ * so give the benefit of the doubt */
+ return 1;
+
+ /* convert to 512-byte sectors */
+ dev_size <<= 1;
+
+ return ((start < dev_size) && (len <= (dev_size - start)));
+}
+
+/*
+ * This upgrades the mode on an already open dm_dev. Being
+ * careful to leave things as they were if we fail to reopen the
+ * device.
+ */
+static int upgrade_mode(struct dm_dev *dd, int new_mode)
+{
+ int r;
+ struct dm_dev dd_copy;
+
+ memcpy(&dd_copy, dd, sizeof(dd_copy));
+
+ dd->mode |= new_mode;
+ dd->bdev = NULL;
+ r = open_dev(dd);
+ if (!r)
+ close_dev(&dd_copy);
+ else
+ memcpy(dd, &dd_copy, sizeof(dd_copy));
+
+ return r;
+}
+
+/*
+ * Add a device to the list, or just increment the usage count if
+ * it's already present.
+ */
+int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
+ sector_t len, int mode, struct dm_dev **result)
+{
+ int r;
+ kdev_t dev;
+ struct dm_dev *dd;
+ unsigned major, minor;
+ struct dm_table *t = ti->table;
+
+ if (!t)
+ BUG();
+
+ if (sscanf(path, "%u:%u", &major, &minor) == 2) {
+ /* Extract the major/minor numbers */
+ dev = mk_kdev(major, minor);
+ } else {
+ /* convert the path to a device */
+ if ((r = lookup_device(path, &dev)))
+ return r;
+ }
+
+ dd = find_device(&t->devices, dev);
+ if (!dd) {
+ dd = kmalloc(sizeof(*dd), GFP_KERNEL);
+ if (!dd)
+ return -ENOMEM;
+
+ dd->dev = dev;
+ dd->mode = mode;
+ dd->bdev = NULL;
+
+ if ((r = open_dev(dd))) {
+ kfree(dd);
+ return r;
+ }
+
+ atomic_set(&dd->count, 0);
+ list_add(&dd->list, &t->devices);
+
+ } else if (dd->mode != (mode | dd->mode)) {
+ r = upgrade_mode(dd, mode);
+ if (r)
+ return r;
+ }
+ atomic_inc(&dd->count);
+
+ if (!check_device_area(dd->dev, start, len)) {
+ DMWARN("device %s too small for target", path);
+ dm_put_device(ti, dd);
+ return -EINVAL;
+ }
+
+ *result = dd;
+
+ return 0;
+}
+
+/*
+ * Decrement a devices use count and remove it if neccessary.
+ */
+void dm_put_device(struct dm_target *ti, struct dm_dev *dd)
+{
+ if (atomic_dec_and_test(&dd->count)) {
+ close_dev(dd);
+ list_del(&dd->list);
+ kfree(dd);
+ }
+}
+
+/*
+ * Checks to see if the target joins onto the end of the table.
+ */
+static int adjoin(struct dm_table *table, struct dm_target *ti)
+{
+ struct dm_target *prev;
+
+ if (!table->num_targets)
+ return !ti->begin;
+
+ prev = &table->targets[table->num_targets - 1];
+ return (ti->begin == (prev->begin + prev->len));
+}
+
+/*
+ * Used to dynamically allocate the arg array.
+ */
+static char **realloc_argv(unsigned *array_size, char **old_argv)
+{
+ char **argv;
+ unsigned new_size;
+
+ new_size = *array_size ? *array_size * 2 : 64;
+ argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL);
+ if (argv) {
+ memcpy(argv, old_argv, *array_size * sizeof(*argv));
+ *array_size = new_size;
+ }
+
+ kfree(old_argv);
+ return argv;
+}
+
+/*
+ * Destructively splits up the argument list to pass to ctr.
+ */
+static int split_args(int *argc, char ***argvp, char *input)
+{
+ char *start, *end = input, *out, **argv = NULL;
+ unsigned array_size = 0;
+
+ *argc = 0;
+ argv = realloc_argv(&array_size, argv);
+ if (!argv)
+ return -ENOMEM;
+
+ while (1) {
+ start = end;
+
+ /* Skip whitespace */
+ while (*start && isspace(*start))
+ start++;
+
+ if (!*start)
+ break; /* success, we hit the end */
+
+ /* 'out' is used to remove any back-quotes */
+ end = out = start;
+ while (*end) {
+ /* Everything apart from '\0' can be quoted */
+ if (*end == '\\' && *(end + 1)) {
+ *out++ = *(end + 1);
+ end += 2;
+ continue;
+ }
+
+ if (isspace(*end))
+ break; /* end of token */
+
+ *out++ = *end++;
+ }
+
+ /* have we already filled the array ? */
+ if ((*argc + 1) > array_size) {
+ argv = realloc_argv(&array_size, argv);
+ if (!argv)
+ return -ENOMEM;
+ }
+
+ /* we know this is whitespace */
+ if (*end)
+ end++;
+
+ /* terminate the string and put it in the array */
+ *out = '\0';
+ argv[*argc] = start;
+ (*argc)++;
+ }
+
+ *argvp = argv;
+ return 0;
+}
+
+int dm_table_add_target(struct dm_table *t, const char *type,
+ sector_t start, sector_t len, char *params)
+{
+ int r = -EINVAL, argc;
+ char **argv;
+ struct dm_target *tgt;
+
+ if (t->num_targets >= t->num_allocated)
+ return -ENOMEM;
+
+ tgt = t->targets + t->num_targets;
+ memset(tgt, 0, sizeof(*tgt));
+
+ tgt->type = dm_get_target_type(type);
+ if (!tgt->type) {
+ tgt->error = "unknown target type";
+ return -EINVAL;
+ }
+
+ tgt->table = t;
+ tgt->begin = start;
+ tgt->len = len;
+ tgt->error = "Unknown error";
+
+ /*
+ * Does this target adjoin the previous one ?
+ */
+ if (!adjoin(t, tgt)) {
+ tgt->error = "Gap in table";
+ r = -EINVAL;
+ goto bad;
+ }
+
+ r = split_args(&argc, &argv, params);
+ if (r) {
+ tgt->error = "couldn't split parameters (insufficient memory)";
+ goto bad;
+ }
+
+ r = tgt->type->ctr(tgt, argc, argv);
+ kfree(argv);
+ if (r)
+ goto bad;
+
+ t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+ return 0;
+
+ bad:
+ printk(KERN_ERR DM_NAME ": %s\n", tgt->error);
+ dm_put_target_type(tgt->type);
+ return r;
+}
+
+static int setup_indexes(struct dm_table *t)
+{
+ int i;
+ unsigned int total = 0;
+ sector_t *indexes;
+
+ /* allocate the space for *all* the indexes */
+ for (i = t->depth - 2; i >= 0; i--) {
+ t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
+ total += t->counts[i];
+ }
+
+ indexes = (sector_t *) vcalloc(total, (unsigned long) NODE_SIZE);
+ if (!indexes)
+ return -ENOMEM;
+
+ /* set up internal nodes, bottom-up */
+ for (i = t->depth - 2, total = 0; i >= 0; i--) {
+ t->index[i] = indexes;
+ indexes += (KEYS_PER_NODE * t->counts[i]);
+ setup_btree_index(i, t);
+ }
+
+ return 0;
+}
+
+/*
+ * Builds the btree to index the map.
+ */
+int dm_table_complete(struct dm_table *t)
+{
+ int r = 0;
+ unsigned int leaf_nodes;
+
+ /* how many indexes will the btree have ? */
+ leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
+ t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
+
+ /* leaf layer has already been set up */
+ t->counts[t->depth - 1] = leaf_nodes;
+ t->index[t->depth - 1] = t->highs;
+
+ if (t->depth >= 2)
+ r = setup_indexes(t);
+
+ return r;
+}
+
+static spinlock_t _event_lock = SPIN_LOCK_UNLOCKED;
+void dm_table_event_callback(struct dm_table *t,
+ void (*fn)(void *), void *context)
+{
+ spin_lock_irq(&_event_lock);
+ t->event_fn = fn;
+ t->event_context = context;
+ spin_unlock_irq(&_event_lock);
+}
+
+void dm_table_event(struct dm_table *t)
+{
+ spin_lock(&_event_lock);
+ if (t->event_fn)
+ t->event_fn(t->event_context);
+ spin_unlock(&_event_lock);
+}
+
+sector_t dm_table_get_size(struct dm_table *t)
+{
+ return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
+}
+
+struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
+{
+ if (index > t->num_targets)
+ return NULL;
+
+ return t->targets + index;
+}
+
+/*
+ * Search the btree for the correct target.
+ */
+struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
+{
+ unsigned int l, n = 0, k = 0;
+ sector_t *node;
+
+ for (l = 0; l < t->depth; l++) {
+ n = get_child(n, k);
+ node = get_node(t, l, n);
+
+ for (k = 0; k < KEYS_PER_NODE; k++)
+ if (node[k] >= sector)
+ break;
+ }
+
+ return &t->targets[(KEYS_PER_NODE * n) + k];
+}
+
+unsigned int dm_table_get_num_targets(struct dm_table *t)
+{
+ return t->num_targets;
+}
+
+struct list_head *dm_table_get_devices(struct dm_table *t)
+{
+ return &t->devices;
+}
+
+int dm_table_get_mode(struct dm_table *t)
+{
+ return t->mode;
+}
+
+void dm_table_suspend_targets(struct dm_table *t)
+{
+ int i;
+
+ for (i = 0; i < t->num_targets; i++) {
+ struct dm_target *ti = t->targets + i;
+
+ if (ti->type->suspend)
+ ti->type->suspend(ti);
+ }
+}
+
+void dm_table_resume_targets(struct dm_table *t)
+{
+ int i;
+
+ for (i = 0; i < t->num_targets; i++) {
+ struct dm_target *ti = t->targets + i;
+
+ if (ti->type->resume)
+ ti->type->resume(ti);
+ }
+}
+
+EXPORT_SYMBOL(dm_get_device);
+EXPORT_SYMBOL(dm_put_device);
+EXPORT_SYMBOL(dm_table_event);
+EXPORT_SYMBOL(dm_table_get_mode);
--- linux-2.4.26-rc1/drivers/md/dm-target.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm-target.c Wed Mar 31 13:54:19 2004
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) 2001 Sistina Software (UK) Limited
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+
+struct tt_internal {
+ struct target_type tt;
+
+ struct list_head list;
+ long use;
+};
+
+static LIST_HEAD(_targets);
+static DECLARE_RWSEM(_lock);
+
+#define DM_MOD_NAME_SIZE 32
+
+static inline struct tt_internal *__find_target_type(const char *name)
+{
+ struct list_head *tih;
+ struct tt_internal *ti;
+
+ list_for_each(tih, &_targets) {
+ ti = list_entry(tih, struct tt_internal, list);
+
+ if (!strcmp(name, ti->tt.name))
+ return ti;
+ }
+
+ return NULL;
+}
+
+static struct tt_internal *get_target_type(const char *name)
+{
+ struct tt_internal *ti;
+
+ down_read(&_lock);
+ ti = __find_target_type(name);
+
+ if (ti) {
+ if (ti->use == 0 && ti->tt.module)
+ __MOD_INC_USE_COUNT(ti->tt.module);
+ ti->use++;
+ }
+ up_read(&_lock);
+
+ return ti;
+}
+
+static void load_module(const char *name)
+{
+ char module_name[DM_MOD_NAME_SIZE] = "dm-";
+
+ /* Length check for strcat() below */
+ if (strlen(name) > (DM_MOD_NAME_SIZE - 4))
+ return;
+
+ strcat(module_name, name);
+ request_module(module_name);
+}
+
+struct target_type *dm_get_target_type(const char *name)
+{
+ struct tt_internal *ti = get_target_type(name);
+
+ if (!ti) {
+ load_module(name);
+ ti = get_target_type(name);
+ }
+
+ return ti ? &ti->tt : NULL;
+}
+
+void dm_put_target_type(struct target_type *t)
+{
+ struct tt_internal *ti = (struct tt_internal *) t;
+
+ down_read(&_lock);
+ if (--ti->use == 0 && ti->tt.module)
+ __MOD_DEC_USE_COUNT(ti->tt.module);
+
+ if (ti->use < 0)
+ BUG();
+ up_read(&_lock);
+
+ return;
+}
+
+static struct tt_internal *alloc_target(struct target_type *t)
+{
+ struct tt_internal *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
+
+ if (ti) {
+ memset(ti, 0, sizeof(*ti));
+ ti->tt = *t;
+ }
+
+ return ti;
+}
+
+
+int dm_target_iterate(void (*iter_func)(struct target_type *tt,
+ void *param), void *param)
+{
+ struct tt_internal *ti;
+
+ down_read(&_lock);
+ list_for_each_entry (ti, &_targets, list)
+ iter_func(&ti->tt, param);
+ up_read(&_lock);
+
+ return 0;
+}
+
+int dm_register_target(struct target_type *t)
+{
+ int rv = 0;
+ struct tt_internal *ti = alloc_target(t);
+
+ if (!ti)
+ return -ENOMEM;
+
+ down_write(&_lock);
+ if (__find_target_type(t->name)) {
+ kfree(ti);
+ rv = -EEXIST;
+ } else
+ list_add(&ti->list, &_targets);
+
+ up_write(&_lock);
+ return rv;
+}
+
+int dm_unregister_target(struct target_type *t)
+{
+ struct tt_internal *ti;
+
+ down_write(&_lock);
+ if (!(ti = __find_target_type(t->name))) {
+ up_write(&_lock);
+ return -EINVAL;
+ }
+
+ if (ti->use) {
+ up_write(&_lock);
+ return -ETXTBSY;
+ }
+
+ list_del(&ti->list);
+ kfree(ti);
+
+ up_write(&_lock);
+ return 0;
+}
+
+/*
+ * io-err: always fails an io, useful for bringing
+ * up LVs that have holes in them.
+ */
+static int io_err_ctr(struct dm_target *ti, unsigned int argc, char **args)
+{
+ return 0;
+}
+
+static void io_err_dtr(struct dm_target *ti)
+{
+ /* empty */
+}
+
+static int io_err_map(struct dm_target *ti, struct buffer_head *bh, int rw,
+ union map_info *map_context)
+{
+ return -EIO;
+}
+
+static struct target_type error_target = {
+ .name = "error",
+ .version = {1, 0, 1},
+ .ctr = io_err_ctr,
+ .dtr = io_err_dtr,
+ .map = io_err_map,
+};
+
+int dm_target_init(void)
+{
+ return dm_register_target(&error_target);
+}
+
+void dm_target_exit(void)
+{
+ if (dm_unregister_target(&error_target))
+ DMWARN("error target unregistration failed");
+}
+
+EXPORT_SYMBOL(dm_register_target);
+EXPORT_SYMBOL(dm_unregister_target);
--- linux-2.4.26-rc1/drivers/md/dm.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,1115 @@
+/*
+ * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "kcopyd.h"
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/blk.h>
+#include <linux/blkpg.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/major.h>
+#include <linux/kdev_t.h>
+#include <linux/lvm.h>
+
+#include <asm/uaccess.h>
+
+static const char *_name = DM_NAME;
+#define DEFAULT_READ_AHEAD 64
+
+struct dm_io {
+ struct mapped_device *md;
+
+ struct dm_target *ti;
+ int rw;
+ union map_info map_context;
+ void (*end_io) (struct buffer_head * bh, int uptodate);
+ void *context;
+};
+
+struct deferred_io {
+ int rw;
+ struct buffer_head *bh;
+ struct deferred_io *next;
+};
+
+/*
+ * Bits for the md->flags field.
+ */
+#define DMF_BLOCK_IO 0
+#define DMF_SUSPENDED 1
+
+struct mapped_device {
+ struct rw_semaphore lock;
+ atomic_t holders;
+
+ kdev_t dev;
+ unsigned long flags;
+
+ /*
+ * A list of ios that arrived while we were suspended.
+ */
+ atomic_t pending;
+ wait_queue_head_t wait;
+ struct deferred_io *deferred;
+
+ /*
+ * The current mapping.
+ */
+ struct dm_table *map;
+
+ /*
+ * io objects are allocated from here.
+ */
+ mempool_t *io_pool;
+
+ /*
+ * Event handling.
+ */
+ uint32_t event_nr;
+ wait_queue_head_t eventq;
+};
+
+#define MIN_IOS 256
+static kmem_cache_t *_io_cache;
+
+static struct mapped_device *get_kdev(kdev_t dev);
+static int dm_request(request_queue_t *q, int rw, struct buffer_head *bh);
+static int dm_user_bmap(struct inode *inode, struct lv_bmap *lvb);
+
+/*-----------------------------------------------------------------
+ * In order to avoid the 256 minor number limit we are going to
+ * register more major numbers as neccessary.
+ *---------------------------------------------------------------*/
+#define MAX_MINORS (1 << MINORBITS)
+
+struct major_details {
+ unsigned int major;
+
+ int transient;
+ struct list_head transient_list;
+
+ unsigned int first_free_minor;
+ int nr_free_minors;
+
+ struct mapped_device *mds[MAX_MINORS];
+ int blk_size[MAX_MINORS];
+ int blksize_size[MAX_MINORS];
+ int hardsect_size[MAX_MINORS];
+};
+
+static struct rw_semaphore _dev_lock;
+static struct major_details *_majors[MAX_BLKDEV];
+
+/*
+ * This holds a list of majors that non-specified device numbers
+ * may be allocated from. Only majors with free minors appear on
+ * this list.
+ */
+static LIST_HEAD(_transients_free);
+
+static int __alloc_major(unsigned int major, struct major_details **result)
+{
+ int r;
+ unsigned int transient = !major;
+ struct major_details *maj;
+
+ /* Major already allocated? */
+ if (major && _majors[major])
+ return 0;
+
+ maj = kmalloc(sizeof(*maj), GFP_KERNEL);
+ if (!maj)
+ return -ENOMEM;
+
+ memset(maj, 0, sizeof(*maj));
+ INIT_LIST_HEAD(&maj->transient_list);
+
+ maj->nr_free_minors = MAX_MINORS;
+
+ r = register_blkdev(major, _name, &dm_blk_dops);
+ if (r < 0) {
+ DMERR("register_blkdev failed for %d", major);
+ kfree(maj);
+ return r;
+ }
+ if (r > 0)
+ major = r;
+
+ maj->major = major;
+
+ if (transient) {
+ maj->transient = transient;
+ list_add_tail(&maj->transient_list, &_transients_free);
+ }
+
+ _majors[major] = maj;
+
+ blk_size[major] = maj->blk_size;
+ blksize_size[major] = maj->blksize_size;
+ hardsect_size[major] = maj->hardsect_size;
+ read_ahead[major] = DEFAULT_READ_AHEAD;
+
+ blk_queue_make_request(BLK_DEFAULT_QUEUE(major), dm_request);
+
+ *result = maj;
+ return 0;
+}
+
+static void __free_major(struct major_details *maj)
+{
+ unsigned int major = maj->major;
+
+ list_del(&maj->transient_list);
+
+ read_ahead[major] = 0;
+ blk_size[major] = NULL;
+ blksize_size[major] = NULL;
+ hardsect_size[major] = NULL;
+
+ _majors[major] = NULL;
+ kfree(maj);
+
+ if (unregister_blkdev(major, _name) < 0)
+ DMERR("devfs_unregister_blkdev failed");
+}
+
+static void free_all_majors(void)
+{
+ unsigned int major = ARRAY_SIZE(_majors);
+
+ down_write(&_dev_lock);
+
+ while (major--)
+ if (_majors[major])
+ __free_major(_majors[major]);
+
+ up_write(&_dev_lock);
+}
+
+static void free_dev(kdev_t dev)
+{
+ unsigned int major = major(dev);
+ unsigned int minor = minor(dev);
+ struct major_details *maj;
+
+ down_write(&_dev_lock);
+
+ maj = _majors[major];
+ if (!maj)
+ goto out;
+
+ maj->mds[minor] = NULL;
+ maj->nr_free_minors++;
+
+ if (maj->nr_free_minors == MAX_MINORS) {
+ __free_major(maj);
+ goto out;
+ }
+
+ if (!maj->transient)
+ goto out;
+
+ if (maj->nr_free_minors == 1)
+ list_add_tail(&maj->transient_list, &_transients_free);
+
+ if (minor < maj->first_free_minor)
+ maj->first_free_minor = minor;
+
+ out:
+ up_write(&_dev_lock);
+}
+
+static void __alloc_minor(struct major_details *maj, unsigned int minor,
+ struct mapped_device *md)
+{
+ maj->mds[minor] = md;
+ md->dev = mk_kdev(maj->major, minor);
+ maj->nr_free_minors--;
+
+ if (maj->transient && !maj->nr_free_minors)
+ list_del_init(&maj->transient_list);
+}
+
+/*
+ * See if requested kdev_t is available.
+ */
+static int specific_dev(kdev_t dev, struct mapped_device *md)
+{
+ int r = 0;
+ unsigned int major = major(dev);
+ unsigned int minor = minor(dev);
+ struct major_details *maj;
+
+ if (!major || (major > MAX_BLKDEV) || (minor >= MAX_MINORS)) {
+ DMWARN("device number requested out of range (%d, %d)",
+ major, minor);
+ return -EINVAL;
+ }
+
+ down_write(&_dev_lock);
+ maj = _majors[major];
+
+ /* Register requested major? */
+ if (!maj) {
+ r = __alloc_major(major, &maj);
+ if (r)
+ goto out;
+
+ major = maj->major;
+ }
+
+ if (maj->mds[minor]) {
+ r = -EBUSY;
+ goto out;
+ }
+
+ __alloc_minor(maj, minor, md);
+
+ out:
+ up_write(&_dev_lock);
+
+ return r;
+}
+
+/*
+ * Find first unused device number, requesting a new major number if required.
+ */
+static int first_free_dev(struct mapped_device *md)
+{
+ int r = 0;
+ struct major_details *maj;
+
+ down_write(&_dev_lock);
+
+ if (list_empty(&_transients_free)) {
+ r = __alloc_major(0, &maj);
+ if (r)
+ goto out;
+ } else
+ maj = list_entry(_transients_free.next, struct major_details,
+ transient_list);
+
+ while (maj->mds[maj->first_free_minor++])
+ ;
+
+ __alloc_minor(maj, maj->first_free_minor - 1, md);
+
+ out:
+ up_write(&_dev_lock);
+
+ return r;
+}
+
+static struct mapped_device *get_kdev(kdev_t dev)
+{
+ struct mapped_device *md;
+ struct major_details *maj;
+
+ down_read(&_dev_lock);
+ maj = _majors[major(dev)];
+ if (!maj) {
+ md = NULL;
+ goto out;
+ }
+ md = maj->mds[minor(dev)];
+ if (md)
+ dm_get(md);
+ out:
+ up_read(&_dev_lock);
+
+ return md;
+}
+
+/*-----------------------------------------------------------------
+ * init/exit code
+ *---------------------------------------------------------------*/
+
+static __init int local_init(void)
+{
+ init_rwsem(&_dev_lock);
+
+ /* allocate a slab for the dm_ios */
+ _io_cache = kmem_cache_create("dm io",
+ sizeof(struct dm_io), 0, 0, NULL, NULL);
+
+ if (!_io_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void local_exit(void)
+{
+ kmem_cache_destroy(_io_cache);
+ free_all_majors();
+
+ DMINFO("cleaned up");
+}
+
+/*
+ * We have a lot of init/exit functions, so it seems easier to
+ * store them in an array. The disposable macro 'xx'
+ * expands a prefix into a pair of function names.
+ */
+static struct {
+ int (*init) (void);
+ void (*exit) (void);
+
+} _inits[] = {
+#define xx(n) {n ## _init, n ## _exit},
+ xx(local)
+ xx(kcopyd)
+ xx(dm_target)
+ xx(dm_linear)
+ xx(dm_stripe)
+ xx(dm_snapshot)
+ xx(dm_interface)
+#undef xx
+};
+
+static int __init dm_init(void)
+{
+ const int count = ARRAY_SIZE(_inits);
+
+ int r, i;
+
+ for (i = 0; i < count; i++) {
+ r = _inits[i].init();
+ if (r)
+ goto bad;
+ }
+
+ return 0;
+
+ bad:
+ while (i--)
+ _inits[i].exit();
+
+ return r;
+}
+
+static void __exit dm_exit(void)
+{
+ int i = ARRAY_SIZE(_inits);
+
+ while (i--)
+ _inits[i].exit();
+}
+
+/*
+ * Block device functions
+ */
+static int dm_blk_open(struct inode *inode, struct file *file)
+{
+ struct mapped_device *md;
+
+ md = get_kdev(inode->i_rdev);
+ if (!md)
+ return -ENXIO;
+
+ return 0;
+}
+
+static int dm_blk_close(struct inode *inode, struct file *file)
+{
+ struct mapped_device *md;
+
+ md = get_kdev(inode->i_rdev);
+ dm_put(md); /* put the reference gained by dm_blk_open */
+ dm_put(md);
+ return 0;
+}
+
+static inline struct dm_io *alloc_io(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_NOIO);
+}
+
+static inline void free_io(struct mapped_device *md, struct dm_io *io)
+{
+ mempool_free(io, md->io_pool);
+}
+
+static inline struct deferred_io *alloc_deferred(void)
+{
+ return kmalloc(sizeof(struct deferred_io), GFP_NOIO);
+}
+
+static inline void free_deferred(struct deferred_io *di)
+{
+ kfree(di);
+}
+
+static inline sector_t volume_size(kdev_t dev)
+{
+ return blk_size[major(dev)][minor(dev)] << 1;
+}
+
+/* FIXME: check this */
+static int dm_blk_ioctl(struct inode *inode, struct file *file,
+ unsigned int command, unsigned long a)
+{
+ kdev_t dev = inode->i_rdev;
+ long size;
+
+ switch (command) {
+ case BLKROSET:
+ case BLKROGET:
+ case BLKRASET:
+ case BLKRAGET:
+ case BLKFLSBUF:
+ case BLKSSZGET:
+ //case BLKRRPART: /* Re-read partition tables */
+ //case BLKPG:
+ case BLKELVGET:
+ case BLKELVSET:
+ case BLKBSZGET:
+ case BLKBSZSET:
+ return blk_ioctl(dev, command, a);
+ break;
+
+ case BLKGETSIZE:
+ size = volume_size(dev);
+ if (copy_to_user((void *) a, &size, sizeof(long)))
+ return -EFAULT;
+ break;
+
+ case BLKGETSIZE64:
+ size = volume_size(dev);
+ if (put_user((u64) ((u64) size) << 9, (u64 *) a))
+ return -EFAULT;
+ break;
+
+ case BLKRRPART:
+ return -ENOTTY;
+
+ case LV_BMAP:
+ return dm_user_bmap(inode, (struct lv_bmap *) a);
+
+ default:
+ DMWARN("unknown block ioctl 0x%x", command);
+ return -ENOTTY;
+ }
+
+ return 0;
+}
+
+/*
+ * Add the buffer to the list of deferred io.
+ */
+static int queue_io(struct mapped_device *md, struct buffer_head *bh, int rw)
+{
+ struct deferred_io *di;
+
+ di = alloc_deferred();
+ if (!di)
+ return -ENOMEM;
+
+ down_write(&md->lock);
+
+ if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
+ up_write(&md->lock);
+ free_deferred(di);
+ return 1;
+ }
+
+ di->bh = bh;
+ di->rw = rw;
+ di->next = md->deferred;
+ md->deferred = di;
+
+ up_write(&md->lock);
+ return 0; /* deferred successfully */
+}
+
+/*
+ * bh->b_end_io routine that decrements the pending count
+ * and then calls the original bh->b_end_io fn.
+ */
+static void dec_pending(struct buffer_head *bh, int uptodate)
+{
+ int r;
+ struct dm_io *io = bh->b_private;
+ dm_endio_fn endio = io->ti->type->end_io;
+
+ if (endio) {
+ r = endio(io->ti, bh, io->rw, uptodate ? 0 : -EIO,
+ &io->map_context);
+ if (r < 0)
+ uptodate = 0;
+
+ else if (r > 0)
+ /* the target wants another shot at the io */
+ return;
+ }
+
+ if (atomic_dec_and_test(&io->md->pending))
+ /* nudge anyone waiting on suspend queue */
+ wake_up(&io->md->wait);
+
+ bh->b_end_io = io->end_io;
+ bh->b_private = io->context;
+ free_io(io->md, io);
+
+ bh->b_end_io(bh, uptodate);
+}
+
+/*
+ * Do the bh mapping for a given leaf
+ */
+static inline int __map_buffer(struct mapped_device *md, int rw,
+ struct buffer_head *bh, struct dm_io *io)
+{
+ struct dm_target *ti;
+
+ if (!md->map)
+ return -EINVAL;
+
+ ti = dm_table_find_target(md->map, bh->b_rsector);
+ if (!ti->type)
+ return -EINVAL;
+
+ /* hook the end io request fn */
+ atomic_inc(&md->pending);
+ io->md = md;
+ io->ti = ti;
+ io->rw = rw;
+ io->end_io = bh->b_end_io;
+ io->context = bh->b_private;
+ bh->b_end_io = dec_pending;
+ bh->b_private = io;
+
+ return ti->type->map(ti, bh, rw, &io->map_context);
+}
+
+/*
+ * Checks to see if we should be deferring io, if so it queues it
+ * and returns 1.
+ */
+static inline int __deferring(struct mapped_device *md, int rw,
+ struct buffer_head *bh)
+{
+ int r;
+
+ /*
+ * If we're suspended we have to queue this io for later.
+ */
+ while (test_bit(DMF_BLOCK_IO, &md->flags)) {
+ up_read(&md->lock);
+
+ /*
+ * There's no point deferring a read ahead
+ * request, just drop it.
+ */
+ if (rw == READA) {
+ down_read(&md->lock);
+ return -EIO;
+ }
+
+ r = queue_io(md, bh, rw);
+ down_read(&md->lock);
+
+ if (r < 0)
+ return r;
+
+ if (r == 0)
+ return 1; /* deferred successfully */
+
+ }
+
+ return 0;
+}
+
+static int dm_request(request_queue_t *q, int rw, struct buffer_head *bh)
+{
+ int r;
+ struct dm_io *io;
+ struct mapped_device *md;
+
+ md = get_kdev(bh->b_rdev);
+ if (!md) {
+ buffer_IO_error(bh);
+ return 0;
+ }
+
+ io = alloc_io(md);
+ down_read(&md->lock);
+
+ r = __deferring(md, rw, bh);
+ if (r < 0)
+ goto bad;
+
+ else if (!r) {
+ /* not deferring */
+ r = __map_buffer(md, rw, bh, io);
+ if (r < 0)
+ goto bad;
+ } else
+ r = 0;
+
+ up_read(&md->lock);
+ dm_put(md);
+ return r;
+
+ bad:
+ buffer_IO_error(bh);
+ up_read(&md->lock);
+ dm_put(md);
+ return 0;
+}
+
+static int check_dev_size(kdev_t dev, unsigned long block)
+{
+ unsigned int major = major(dev);
+ unsigned int minor = minor(dev);
+
+ /* FIXME: check this */
+ unsigned long max_sector = (blk_size[major][minor] << 1) + 1;
+ unsigned long sector = (block + 1) * (blksize_size[major][minor] >> 9);
+
+ return (sector > max_sector) ? 0 : 1;
+}
+
+/*
+ * Creates a dummy buffer head and maps it (for lilo).
+ */
+static int __bmap(struct mapped_device *md, kdev_t dev, unsigned long block,
+ kdev_t *r_dev, unsigned long *r_block)
+{
+ struct buffer_head bh;
+ struct dm_target *ti;
+ union map_info map_context;
+ int r;
+
+ if (test_bit(DMF_BLOCK_IO, &md->flags)) {
+ return -EPERM;
+ }
+
+ if (!check_dev_size(dev, block)) {
+ return -EINVAL;
+ }
+
+ if (!md->map)
+ return -EINVAL;
+
+ /* setup dummy bh */
+ memset(&bh, 0, sizeof(bh));
+ bh.b_blocknr = block;
+ bh.b_dev = bh.b_rdev = dev;
+ bh.b_size = blksize_size[major(dev)][minor(dev)];
+ bh.b_rsector = block * (bh.b_size >> 9);
+
+ /* find target */
+ ti = dm_table_find_target(md->map, bh.b_rsector);
+
+ /* do the mapping */
+ r = ti->type->map(ti, &bh, READ, &map_context);
+ ti->type->end_io(ti, &bh, READ, 0, &map_context);
+
+ if (!r) {
+ *r_dev = bh.b_rdev;
+ *r_block = bh.b_rsector / (bh.b_size >> 9);
+ }
+
+ return r;
+}
+
+/*
+ * Marshals arguments and results between user and kernel space.
+ */
+static int dm_user_bmap(struct inode *inode, struct lv_bmap *lvb)
+{
+ struct mapped_device *md;
+ unsigned long block, r_block;
+ kdev_t r_dev;
+ int r;
+
+ if (get_user(block, &lvb->lv_block))
+ return -EFAULT;
+
+ md = get_kdev(inode->i_rdev);
+ if (!md)
+ return -ENXIO;
+
+ down_read(&md->lock);
+ r = __bmap(md, inode->i_rdev, block, &r_dev, &r_block);
+ up_read(&md->lock);
+ dm_put(md);
+
+ if (!r && (put_user(kdev_t_to_nr(r_dev), &lvb->lv_dev) ||
+ put_user(r_block, &lvb->lv_block)))
+ r = -EFAULT;
+
+ return r;
+}
+
+static void free_md(struct mapped_device *md)
+{
+ free_dev(md->dev);
+ mempool_destroy(md->io_pool);
+ kfree(md);
+}
+
+/*
+ * Allocate and initialise a blank device with a given minor.
+ */
+static struct mapped_device *alloc_md(kdev_t dev)
+{
+ int r;
+ struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
+
+ if (!md) {
+ DMWARN("unable to allocate device, out of memory.");
+ return NULL;
+ }
+
+ memset(md, 0, sizeof(*md));
+
+ /* Allocate suitable device number */
+ if (!dev)
+ r = first_free_dev(md);
+ else
+ r = specific_dev(dev, md);
+
+ if (r) {
+ kfree(md);
+ return NULL;
+ }
+
+ md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
+ mempool_free_slab, _io_cache);
+ if (!md->io_pool) {
+ free_md(md);
+ kfree(md);
+ return NULL;
+ }
+
+ init_rwsem(&md->lock);
+ atomic_set(&md->holders, 1);
+ atomic_set(&md->pending, 0);
+ init_waitqueue_head(&md->wait);
+ init_waitqueue_head(&md->eventq);
+
+ return md;
+}
+
+/*
+ * The hardsect size for a mapped device is the largest hardsect size
+ * from the devices it maps onto.
+ */
+static int __find_hardsect_size(struct list_head *devices)
+{
+ int result = 512, size;
+ struct list_head *tmp;
+
+ list_for_each (tmp, devices) {
+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+ size = get_hardsect_size(dd->dev);
+ if (size > result)
+ result = size;
+ }
+
+ return result;
+}
+
+/*
+ * Bind a table to the device.
+ */
+static void event_callback(void *context)
+{
+ struct mapped_device *md = (struct mapped_device *) context;
+
+ down_write(&md->lock);
+ md->event_nr++;
+ wake_up_interruptible(&md->eventq);
+ up_write(&md->lock);
+}
+
+static int __bind(struct mapped_device *md, struct dm_table *t)
+{
+ unsigned int minor = minor(md->dev);
+ unsigned int major = major(md->dev);
+ md->map = t;
+
+ /* in k */
+ blk_size[major][minor] = dm_table_get_size(t) >> 1;
+ blksize_size[major][minor] = BLOCK_SIZE;
+ hardsect_size[major][minor] =
+ __find_hardsect_size(dm_table_get_devices(t));
+ register_disk(NULL, md->dev, 1, &dm_blk_dops, blk_size[major][minor]);
+
+ dm_table_event_callback(md->map, event_callback, md);
+ dm_table_get(t);
+ return 0;
+}
+
+static void __unbind(struct mapped_device *md)
+{
+ unsigned int minor = minor(md->dev);
+ unsigned int major = major(md->dev);
+
+ if (md->map) {
+ dm_table_event_callback(md->map, NULL, NULL);
+ dm_table_put(md->map);
+ md->map = NULL;
+
+ }
+
+ blk_size[major][minor] = 0;
+ blksize_size[major][minor] = 0;
+ hardsect_size[major][minor] = 0;
+}
+
+/*
+ * Constructor for a new device.
+ */
+int dm_create(kdev_t dev, struct mapped_device **result)
+{
+ struct mapped_device *md;
+
+ md = alloc_md(dev);
+ if (!md)
+ return -ENXIO;
+
+ __unbind(md); /* Ensure zero device size */
+
+ *result = md;
+ return 0;
+}
+
+void dm_get(struct mapped_device *md)
+{
+ atomic_inc(&md->holders);
+}
+
+void dm_put(struct mapped_device *md)
+{
+ if (atomic_dec_and_test(&md->holders)) {
+ if (md->map)
+ dm_table_suspend_targets(md->map);
+ __unbind(md);
+ free_md(md);
+ }
+}
+
+/*
+ * Requeue the deferred io by calling generic_make_request.
+ */
+static void flush_deferred_io(struct deferred_io *c)
+{
+ struct deferred_io *n;
+
+ while (c) {
+ n = c->next;
+ generic_make_request(c->rw, c->bh);
+ free_deferred(c);
+ c = n;
+ }
+}
+
+/*
+ * Swap in a new table (destroying old one).
+ */
+int dm_swap_table(struct mapped_device *md, struct dm_table *table)
+{
+ int r;
+
+ down_write(&md->lock);
+
+ /*
+ * The device must be suspended, or have no table bound yet.
+ */
+ if (md->map && !test_bit(DMF_SUSPENDED, &md->flags)) {
+ up_write(&md->lock);
+ return -EPERM;
+ }
+
+ __unbind(md);
+ r = __bind(md, table);
+ if (r)
+ return r;
+
+ up_write(&md->lock);
+ return 0;
+}
+
+/*
+ * We need to be able to change a mapping table under a mounted
+ * filesystem. For example we might want to move some data in
+ * the background. Before the table can be swapped with
+ * dm_bind_table, dm_suspend must be called to flush any in
+ * flight io and ensure that any further io gets deferred.
+ */
+int dm_suspend(struct mapped_device *md)
+{
+ int r = 0;
+ DECLARE_WAITQUEUE(wait, current);
+
+ down_write(&md->lock);
+
+ /*
+ * First we set the BLOCK_IO flag so no more ios will be
+ * mapped.
+ */
+ if (test_bit(DMF_BLOCK_IO, &md->flags)) {
+ up_write(&md->lock);
+ return -EINVAL;
+ }
+
+ set_bit(DMF_BLOCK_IO, &md->flags);
+ add_wait_queue(&md->wait, &wait);
+ up_write(&md->lock);
+
+ /*
+ * Then we wait for the already mapped ios to
+ * complete.
+ */
+ run_task_queue(&tq_disk);
+ while (1) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (!atomic_read(&md->pending) || signal_pending(current))
+ break;
+
+ schedule();
+ }
+ set_current_state(TASK_RUNNING);
+
+ down_write(&md->lock);
+ remove_wait_queue(&md->wait, &wait);
+
+ /* did we flush everything ? */
+ if (atomic_read(&md->pending)) {
+ clear_bit(DMF_BLOCK_IO, &md->flags);
+ r = -EINTR;
+ } else {
+ set_bit(DMF_SUSPENDED, &md->flags);
+ if (md->map)
+ dm_table_suspend_targets(md->map);
+ }
+ up_write(&md->lock);
+
+ return r;
+}
+
+int dm_resume(struct mapped_device *md)
+{
+ struct deferred_io *def;
+
+ down_write(&md->lock);
+ if (!test_bit(DMF_SUSPENDED, &md->flags)) {
+ up_write(&md->lock);
+ return -EINVAL;
+ }
+
+ if (md->map)
+ dm_table_resume_targets(md->map);
+
+ clear_bit(DMF_SUSPENDED, &md->flags);
+ clear_bit(DMF_BLOCK_IO, &md->flags);
+ def = md->deferred;
+ md->deferred = NULL;
+ up_write(&md->lock);
+
+ flush_deferred_io(def);
+ run_task_queue(&tq_disk);
+
+ return 0;
+}
+
+struct dm_table *dm_get_table(struct mapped_device *md)
+{
+ struct dm_table *t;
+
+ down_read(&md->lock);
+ t = md->map;
+ if (t)
+ dm_table_get(t);
+ up_read(&md->lock);
+
+ return t;
+}
+
+/*-----------------------------------------------------------------
+ * Event notification.
+ *---------------------------------------------------------------*/
+uint32_t dm_get_event_nr(struct mapped_device *md)
+{
+ uint32_t r;
+
+ down_read(&md->lock);
+ r = md->event_nr;
+ up_read(&md->lock);
+
+ return r;
+}
+
+int dm_add_wait_queue(struct mapped_device *md, wait_queue_t *wq,
+ uint32_t event_nr)
+{
+ down_write(&md->lock);
+ if (event_nr != md->event_nr) {
+ up_write(&md->lock);
+ return 1;
+ }
+
+ add_wait_queue(&md->eventq, wq);
+ up_write(&md->lock);
+
+ return 0;
+}
+
+const char *dm_kdevname(kdev_t dev)
+{
+ static char buffer[32];
+ sprintf(buffer, "%03d:%03d", MAJOR(dev), MINOR(dev));
+ return buffer;
+}
+
+void dm_remove_wait_queue(struct mapped_device *md, wait_queue_t *wq)
+{
+ down_write(&md->lock);
+ remove_wait_queue(&md->eventq, wq);
+ up_write(&md->lock);
+}
+
+kdev_t dm_kdev(struct mapped_device *md)
+{
+ kdev_t dev;
+
+ down_read(&md->lock);
+ dev = md->dev;
+ up_read(&md->lock);
+
+ return dev;
+}
+
+int dm_suspended(struct mapped_device *md)
+{
+ return test_bit(DMF_SUSPENDED, &md->flags);
+}
+
+struct block_device_operations dm_blk_dops = {
+ .open = dm_blk_open,
+ .release = dm_blk_close,
+ .ioctl = dm_blk_ioctl,
+ .owner = THIS_MODULE
+};
+
+/*
+ * module hooks
+ */
+module_init(dm_init);
+module_exit(dm_exit);
+
+MODULE_DESCRIPTION(DM_NAME " driver");
+MODULE_AUTHOR("Joe Thornber <thornber@sistina.com>");
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL(dm_kdevname);
--- linux-2.4.26-rc1/drivers/md/dm.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/dm.h Wed Mar 31 13:49:22 2004
@@ -0,0 +1,177 @@
+/*
+ * Internal header file for device mapper
+ *
+ * Copyright (C) 2001, 2002 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef DM_INTERNAL_H
+#define DM_INTERNAL_H
+
+#include <linux/fs.h>
+#include <linux/device-mapper.h>
+#include <linux/list.h>
+#include <linux/blkdev.h>
+
+#define DM_NAME "device-mapper"
+#define DMWARN(f, x...) printk(KERN_WARNING DM_NAME ": " f "\n" , ## x)
+#define DMERR(f, x...) printk(KERN_ERR DM_NAME ": " f "\n" , ## x)
+#define DMINFO(f, x...) printk(KERN_INFO DM_NAME ": " f "\n" , ## x)
+
+/*
+ * FIXME: I think this should be with the definition of sector_t
+ * in types.h.
+ */
+#ifdef CONFIG_LBD
+#define SECTOR_FORMAT "%Lu"
+#else
+#define SECTOR_FORMAT "%lu"
+#endif
+
+#define SECTOR_SHIFT 9
+#define SECTOR_SIZE (1 << SECTOR_SHIFT)
+
+extern struct block_device_operations dm_blk_dops;
+
+/*
+ * List of devices that a metadevice uses and should open/close.
+ */
+struct dm_dev {
+ struct list_head list;
+
+ atomic_t count;
+ int mode;
+ kdev_t dev;
+ struct block_device *bdev;
+};
+
+struct dm_table;
+struct mapped_device;
+
+/*-----------------------------------------------------------------
+ * Functions for manipulating a struct mapped_device.
+ * Drop the reference with dm_put when you finish with the object.
+ *---------------------------------------------------------------*/
+int dm_create(kdev_t dev, struct mapped_device **md);
+
+/*
+ * Reference counting for md.
+ */
+void dm_get(struct mapped_device *md);
+void dm_put(struct mapped_device *md);
+
+/*
+ * A device can still be used while suspended, but I/O is deferred.
+ */
+int dm_suspend(struct mapped_device *md);
+int dm_resume(struct mapped_device *md);
+
+/*
+ * The device must be suspended before calling this method.
+ */
+int dm_swap_table(struct mapped_device *md, struct dm_table *t);
+
+/*
+ * Drop a reference on the table when you've finished with the
+ * result.
+ */
+struct dm_table *dm_get_table(struct mapped_device *md);
+
+/*
+ * Event functions.
+ */
+uint32_t dm_get_event_nr(struct mapped_device *md);
+int dm_add_wait_queue(struct mapped_device *md, wait_queue_t *wq,
+ uint32_t event_nr);
+void dm_remove_wait_queue(struct mapped_device *md, wait_queue_t *wq);
+
+/*
+ * Info functions.
+ */
+kdev_t dm_kdev(struct mapped_device *md);
+int dm_suspended(struct mapped_device *md);
+
+/*-----------------------------------------------------------------
+ * Functions for manipulating a table. Tables are also reference
+ * counted.
+ *---------------------------------------------------------------*/
+int dm_table_create(struct dm_table **result, int mode, unsigned num_targets);
+
+void dm_table_get(struct dm_table *t);
+void dm_table_put(struct dm_table *t);
+
+int dm_table_add_target(struct dm_table *t, const char *type,
+ sector_t start, sector_t len, char *params);
+int dm_table_complete(struct dm_table *t);
+void dm_table_event_callback(struct dm_table *t,
+ void (*fn)(void *), void *context);
+void dm_table_event(struct dm_table *t);
+sector_t dm_table_get_size(struct dm_table *t);
+struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
+struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
+unsigned int dm_table_get_num_targets(struct dm_table *t);
+struct list_head *dm_table_get_devices(struct dm_table *t);
+int dm_table_get_mode(struct dm_table *t);
+void dm_table_suspend_targets(struct dm_table *t);
+void dm_table_resume_targets(struct dm_table *t);
+
+/*-----------------------------------------------------------------
+ * A registry of target types.
+ *---------------------------------------------------------------*/
+int dm_target_init(void);
+void dm_target_exit(void);
+struct target_type *dm_get_target_type(const char *name);
+void dm_put_target_type(struct target_type *t);
+int dm_target_iterate(void (*iter_func)(struct target_type *tt,
+ void *param), void *param);
+
+
+/*-----------------------------------------------------------------
+ * Useful inlines.
+ *---------------------------------------------------------------*/
+static inline int array_too_big(unsigned long fixed, unsigned long obj,
+ unsigned long num)
+{
+ return (num > (ULONG_MAX - fixed) / obj);
+}
+
+/*
+ * ceiling(n / size) * size
+ */
+static inline unsigned long dm_round_up(unsigned long n, unsigned long size)
+{
+ unsigned long r = n % size;
+ return n + (r ? (size - r) : 0);
+}
+
+/*
+ * Ceiling(n / size)
+ */
+static inline unsigned long dm_div_up(unsigned long n, unsigned long size)
+{
+ return dm_round_up(n, size) / size;
+}
+
+const char *dm_kdevname(kdev_t dev);
+
+/*
+ * The device-mapper can be driven through one of two interfaces;
+ * ioctl or filesystem, depending which patch you have applied.
+ */
+int dm_interface_init(void);
+void dm_interface_exit(void);
+
+/*
+ * Targets for linear and striped mappings
+ */
+int dm_linear_init(void);
+void dm_linear_exit(void);
+
+int dm_stripe_init(void);
+void dm_stripe_exit(void);
+
+int dm_snapshot_init(void);
+void dm_snapshot_exit(void);
+
+#endif
--- linux-2.4.26-rc1/drivers/md/kcopyd.c Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/kcopyd.c Wed Mar 31 13:48:32 2004
@@ -0,0 +1,666 @@
+/*
+ * Copyright (C) 2002 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <asm/atomic.h>
+
+#include <linux/blkdev.h>
+#include <linux/config.h>
+#include <linux/device-mapper.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/locks.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "kcopyd.h"
+#include "dm-daemon.h"
+
+/* FIXME: this is only needed for the DMERR macros */
+#include "dm.h"
+
+static struct dm_daemon _kcopyd;
+
+#define SECTORS_PER_PAGE (PAGE_SIZE / SECTOR_SIZE)
+#define SUB_JOB_SIZE 128
+#define PAGES_PER_SUB_JOB (SUB_JOB_SIZE / SECTORS_PER_PAGE)
+#define SUB_JOB_COUNT 8
+
+/*-----------------------------------------------------------------
+ * Each kcopyd client has its own little pool of preallocated
+ * pages for kcopyd io.
+ *---------------------------------------------------------------*/
+struct kcopyd_client {
+ struct list_head list;
+
+ spinlock_t lock;
+ struct list_head pages;
+ unsigned int nr_pages;
+ unsigned int nr_free_pages;
+ unsigned int max_split;
+};
+
+static inline void __push_page(struct kcopyd_client *kc, struct page *p)
+{
+ list_add(&p->list, &kc->pages);
+ kc->nr_free_pages++;
+}
+
+static inline struct page *__pop_page(struct kcopyd_client *kc)
+{
+ struct page *p;
+
+ p = list_entry(kc->pages.next, struct page, list);
+ list_del(&p->list);
+ kc->nr_free_pages--;
+
+ return p;
+}
+
+static int kcopyd_get_pages(struct kcopyd_client *kc,
+ unsigned int nr, struct list_head *pages)
+{
+ struct page *p;
+ INIT_LIST_HEAD(pages);
+
+ spin_lock(&kc->lock);
+ if (kc->nr_free_pages < nr) {
+ spin_unlock(&kc->lock);
+ return -ENOMEM;
+ }
+
+ while (nr--) {
+ p = __pop_page(kc);
+ list_add(&p->list, pages);
+ }
+ spin_unlock(&kc->lock);
+
+ return 0;
+}
+
+static void kcopyd_put_pages(struct kcopyd_client *kc, struct list_head *pages)
+{
+ struct list_head *tmp, *tmp2;
+
+ spin_lock(&kc->lock);
+ list_for_each_safe (tmp, tmp2, pages)
+ __push_page(kc, list_entry(tmp, struct page, list));
+ spin_unlock(&kc->lock);
+}
+
+/*
+ * These three functions resize the page pool.
+ */
+static void release_pages(struct list_head *pages)
+{
+ struct page *p;
+ struct list_head *tmp, *tmp2;
+
+ list_for_each_safe (tmp, tmp2, pages) {
+ p = list_entry(tmp, struct page, list);
+ UnlockPage(p);
+ __free_page(p);
+ }
+}
+
+static int client_alloc_pages(struct kcopyd_client *kc, unsigned int nr)
+{
+ unsigned int i;
+ struct page *p;
+ LIST_HEAD(new);
+
+ for (i = 0; i < nr; i++) {
+ p = alloc_page(GFP_KERNEL);
+ if (!p) {
+ release_pages(&new);
+ return -ENOMEM;
+ }
+
+ LockPage(p);
+ list_add(&p->list, &new);
+ }
+
+ kcopyd_put_pages(kc, &new);
+ kc->nr_pages += nr;
+ kc->max_split = kc->nr_pages / PAGES_PER_SUB_JOB;
+ if (kc->max_split > SUB_JOB_COUNT)
+ kc->max_split = SUB_JOB_COUNT;
+
+ return 0;
+}
+
+static void client_free_pages(struct kcopyd_client *kc)
+{
+ BUG_ON(kc->nr_free_pages != kc->nr_pages);
+ release_pages(&kc->pages);
+ kc->nr_free_pages = kc->nr_pages = 0;
+}
+
+/*-----------------------------------------------------------------
+ * kcopyd_jobs need to be allocated by the *clients* of kcopyd,
+ * for this reason we use a mempool to prevent the client from
+ * ever having to do io (which could cause a deadlock).
+ *---------------------------------------------------------------*/
+struct kcopyd_job {
+ struct kcopyd_client *kc;
+ struct list_head list;
+ unsigned int flags;
+
+ /*
+ * Error state of the job.
+ */
+ int read_err;
+ unsigned int write_err;
+
+ /*
+ * Either READ or WRITE
+ */
+ int rw;
+ struct io_region source;
+
+ /*
+ * The destinations for the transfer.
+ */
+ unsigned int num_dests;
+ struct io_region dests[KCOPYD_MAX_REGIONS];
+
+ sector_t offset;
+ unsigned int nr_pages;
+ struct list_head pages;
+
+ /*
+ * Set this to ensure you are notified when the job has
+ * completed. 'context' is for callback to use.
+ */
+ kcopyd_notify_fn fn;
+ void *context;
+
+ /*
+ * These fields are only used if the job has been split
+ * into more manageable parts.
+ */
+ struct semaphore lock;
+ atomic_t sub_jobs;
+ sector_t progress;
+};
+
+/* FIXME: this should scale with the number of pages */
+#define MIN_JOBS 512
+
+static kmem_cache_t *_job_cache;
+static mempool_t *_job_pool;
+
+/*
+ * We maintain three lists of jobs:
+ *
+ * i) jobs waiting for pages
+ * ii) jobs that have pages, and are waiting for the io to be issued.
+ * iii) jobs that have completed.
+ *
+ * All three of these are protected by job_lock.
+ */
+static spinlock_t _job_lock = SPIN_LOCK_UNLOCKED;
+
+static LIST_HEAD(_complete_jobs);
+static LIST_HEAD(_io_jobs);
+static LIST_HEAD(_pages_jobs);
+
+static int jobs_init(void)
+{
+ INIT_LIST_HEAD(&_complete_jobs);
+ INIT_LIST_HEAD(&_io_jobs);
+ INIT_LIST_HEAD(&_pages_jobs);
+
+ _job_cache = kmem_cache_create("kcopyd-jobs",
+ sizeof(struct kcopyd_job),
+ __alignof__(struct kcopyd_job),
+ 0, NULL, NULL);
+ if (!_job_cache)
+ return -ENOMEM;
+
+ _job_pool = mempool_create(MIN_JOBS, mempool_alloc_slab,
+ mempool_free_slab, _job_cache);
+ if (!_job_pool) {
+ kmem_cache_destroy(_job_cache);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void jobs_exit(void)
+{
+ BUG_ON(!list_empty(&_complete_jobs));
+ BUG_ON(!list_empty(&_io_jobs));
+ BUG_ON(!list_empty(&_pages_jobs));
+
+ mempool_destroy(_job_pool);
+ kmem_cache_destroy(_job_cache);
+}
+
+/*
+ * Functions to push and pop a job onto the head of a given job
+ * list.
+ */
+static inline struct kcopyd_job *pop(struct list_head *jobs)
+{
+ struct kcopyd_job *job = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&_job_lock, flags);
+
+ if (!list_empty(jobs)) {
+ job = list_entry(jobs->next, struct kcopyd_job, list);
+ list_del(&job->list);
+ }
+ spin_unlock_irqrestore(&_job_lock, flags);
+
+ return job;
+}
+
+static inline void push(struct list_head *jobs, struct kcopyd_job *job)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&_job_lock, flags);
+ list_add_tail(&job->list, jobs);
+ spin_unlock_irqrestore(&_job_lock, flags);
+}
+
+/*
+ * These three functions process 1 item from the corresponding
+ * job list.
+ *
+ * They return:
+ * < 0: error
+ * 0: success
+ * > 0: can't process yet.
+ */
+static int run_complete_job(struct kcopyd_job *job)
+{
+ void *context = job->context;
+ int read_err = job->read_err;
+ unsigned int write_err = job->write_err;
+ kcopyd_notify_fn fn = job->fn;
+
+ kcopyd_put_pages(job->kc, &job->pages);
+ mempool_free(job, _job_pool);
+ fn(read_err, write_err, context);
+ return 0;
+}
+
+static void complete_io(unsigned int error, void *context)
+{
+ struct kcopyd_job *job = (struct kcopyd_job *) context;
+
+ if (error) {
+ if (job->rw == WRITE)
+ job->write_err &= error;
+ else
+ job->read_err = 1;
+
+ if (!test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) {
+ push(&_complete_jobs, job);
+ dm_daemon_wake(&_kcopyd);
+ return;
+ }
+ }
+
+ if (job->rw == WRITE)
+ push(&_complete_jobs, job);
+
+ else {
+ job->rw = WRITE;
+ push(&_io_jobs, job);
+ }
+
+ dm_daemon_wake(&_kcopyd);
+}
+
+/*
+ * Request io on as many buffer heads as we can currently get for
+ * a particular job.
+ */
+static int run_io_job(struct kcopyd_job *job)
+{
+ int r;
+
+ if (job->rw == READ)
+ r = dm_io_async(1, &job->source, job->rw,
+ list_entry(job->pages.next, struct page, list),
+ job->offset, complete_io, job);
+
+ else
+ r = dm_io_async(job->num_dests, job->dests, job->rw,
+ list_entry(job->pages.next, struct page, list),
+ job->offset, complete_io, job);
+
+ return r;
+}
+
+static int run_pages_job(struct kcopyd_job *job)
+{
+ int r;
+
+ job->nr_pages = dm_div_up(job->dests[0].count + job->offset,
+ SECTORS_PER_PAGE);
+ r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages);
+ if (!r) {
+ /* this job is ready for io */
+ push(&_io_jobs, job);
+ return 0;
+ }
+
+ if (r == -ENOMEM)
+ /* can't complete now */
+ return 1;
+
+ return r;
+}
+
+/*
+ * Run through a list for as long as possible. Returns the count
+ * of successful jobs.
+ */
+static int process_jobs(struct list_head *jobs, int (*fn) (struct kcopyd_job *))
+{
+ struct kcopyd_job *job;
+ int r, count = 0;
+
+ while ((job = pop(jobs))) {
+
+ r = fn(job);
+
+ if (r < 0) {
+ /* error this rogue job */
+ if (job->rw == WRITE)
+ job->write_err = (unsigned int) -1;
+ else
+ job->read_err = 1;
+ push(&_complete_jobs, job);
+ break;
+ }
+
+ if (r > 0) {
+ /*
+ * We couldn't service this job ATM, so
+ * push this job back onto the list.
+ */
+ push(jobs, job);
+ break;
+ }
+
+ count++;
+ }
+
+ return count;
+}
+
+/*
+ * kcopyd does this every time it's woken up.
+ */
+static void do_work(void)
+{
+ /*
+ * The order that these are called is *very* important.
+ * complete jobs can free some pages for pages jobs.
+ * Pages jobs when successful will jump onto the io jobs
+ * list. io jobs call wake when they complete and it all
+ * starts again.
+ */
+ process_jobs(&_complete_jobs, run_complete_job);
+ process_jobs(&_pages_jobs, run_pages_job);
+ process_jobs(&_io_jobs, run_io_job);
+ run_task_queue(&tq_disk);
+}
+
+/*
+ * If we are copying a small region we just dispatch a single job
+ * to do the copy, otherwise the io has to be split up into many
+ * jobs.
+ */
+static void dispatch_job(struct kcopyd_job *job)
+{
+ push(&_pages_jobs, job);
+ dm_daemon_wake(&_kcopyd);
+}
+
+static void segment_complete(int read_err,
+ unsigned int write_err, void *context)
+{
+ /* FIXME: tidy this function */
+ sector_t progress = 0;
+ sector_t count = 0;
+ struct kcopyd_job *job = (struct kcopyd_job *) context;
+
+ down(&job->lock);
+
+ /* update the error */
+ if (read_err)
+ job->read_err = 1;
+
+ if (write_err)
+ job->write_err &= write_err;
+
+ /*
+ * Only dispatch more work if there hasn't been an error.
+ */
+ if ((!job->read_err && !job->write_err) ||
+ test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) {
+ /* get the next chunk of work */
+ progress = job->progress;
+ count = job->source.count - progress;
+ if (count) {
+ if (count > SUB_JOB_SIZE)
+ count = SUB_JOB_SIZE;
+
+ job->progress += count;
+ }
+ }
+ up(&job->lock);
+
+ if (count) {
+ int i;
+ struct kcopyd_job *sub_job = mempool_alloc(_job_pool, GFP_NOIO);
+
+ memcpy(sub_job, job, sizeof(*job));
+ sub_job->source.sector += progress;
+ sub_job->source.count = count;
+
+ for (i = 0; i < job->num_dests; i++) {
+ sub_job->dests[i].sector += progress;
+ sub_job->dests[i].count = count;
+ }
+
+ sub_job->fn = segment_complete;
+ sub_job->context = job;
+ dispatch_job(sub_job);
+
+ } else if (atomic_dec_and_test(&job->sub_jobs)) {
+
+ /*
+ * To avoid a race we must keep the job around
+ * until after the notify function has completed.
+ * Otherwise the client may try and stop the job
+ * after we've completed.
+ */
+ job->fn(read_err, write_err, job->context);
+ mempool_free(job, _job_pool);
+ }
+}
+
+/*
+ * Create some little jobs that will do the move between
+ * them.
+ */
+static void split_job(struct kcopyd_job *job)
+{
+ int nr;
+
+ nr = dm_div_up(job->source.count, SUB_JOB_SIZE);
+ if (nr > job->kc->max_split)
+ nr = job->kc->max_split;
+
+ atomic_set(&job->sub_jobs, nr);
+ while (nr--)
+ segment_complete(0, 0u, job);
+}
+
+int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from,
+ unsigned int num_dests, struct io_region *dests,
+ unsigned int flags, kcopyd_notify_fn fn, void *context)
+{
+ struct kcopyd_job *job;
+
+ /*
+ * Allocate a new job.
+ */
+ job = mempool_alloc(_job_pool, GFP_NOIO);
+
+ /*
+ * set up for the read.
+ */
+ job->kc = kc;
+ job->flags = flags;
+ job->read_err = 0;
+ job->write_err = 0;
+ job->rw = READ;
+
+ memcpy(&job->source, from, sizeof(*from));
+
+ job->num_dests = num_dests;
+ memcpy(&job->dests, dests, sizeof(*dests) * num_dests);
+
+ job->offset = 0;
+ job->nr_pages = 0;
+ INIT_LIST_HEAD(&job->pages);
+
+ job->fn = fn;
+ job->context = context;
+
+ if (job->source.count < SUB_JOB_SIZE)
+ dispatch_job(job);
+
+ else {
+ init_MUTEX(&job->lock);
+ job->progress = 0;
+ split_job(job);
+ }
+
+ return 0;
+}
+
+/*
+ * Cancels a kcopyd job, eg. someone might be deactivating a
+ * mirror.
+ */
+int kcopyd_cancel(struct kcopyd_job *job, int block)
+{
+ /* FIXME: finish */
+ return -1;
+}
+
+/*-----------------------------------------------------------------
+ * Unit setup
+ *---------------------------------------------------------------*/
+static DECLARE_MUTEX(_client_lock);
+static LIST_HEAD(_clients);
+
+static int client_add(struct kcopyd_client *kc)
+{
+ down(&_client_lock);
+ list_add(&kc->list, &_clients);
+ up(&_client_lock);
+ return 0;
+}
+
+static void client_del(struct kcopyd_client *kc)
+{
+ down(&_client_lock);
+ list_del(&kc->list);
+ up(&_client_lock);
+}
+
+int kcopyd_client_create(unsigned int nr_pages, struct kcopyd_client **result)
+{
+ int r = 0;
+ struct kcopyd_client *kc;
+
+ if (nr_pages * SECTORS_PER_PAGE < SUB_JOB_SIZE) {
+ DMERR("kcopyd client requested %u pages: minimum is %lu",
+ nr_pages, SUB_JOB_SIZE / SECTORS_PER_PAGE);
+ return -ENOMEM;
+ }
+
+ kc = kmalloc(sizeof(*kc), GFP_KERNEL);
+ if (!kc)
+ return -ENOMEM;
+
+ kc->lock = SPIN_LOCK_UNLOCKED;
+ INIT_LIST_HEAD(&kc->pages);
+ kc->nr_pages = kc->nr_free_pages = 0;
+ r = client_alloc_pages(kc, nr_pages);
+ if (r) {
+ kfree(kc);
+ return r;
+ }
+
+ r = dm_io_get(nr_pages);
+ if (r) {
+ client_free_pages(kc);
+ kfree(kc);
+ return r;
+ }
+
+ r = client_add(kc);
+ if (r) {
+ dm_io_put(nr_pages);
+ client_free_pages(kc);
+ kfree(kc);
+ return r;
+ }
+
+ *result = kc;
+ return 0;
+}
+
+void kcopyd_client_destroy(struct kcopyd_client *kc)
+{
+ dm_io_put(kc->nr_pages);
+ client_free_pages(kc);
+ client_del(kc);
+ kfree(kc);
+}
+
+
+int __init kcopyd_init(void)
+{
+ int r;
+
+ r = jobs_init();
+ if (r)
+ return r;
+
+ r = dm_daemon_start(&_kcopyd, "kcopyd", do_work);
+ if (r)
+ jobs_exit();
+
+ return r;
+}
+
+void kcopyd_exit(void)
+{
+ jobs_exit();
+ dm_daemon_stop(&_kcopyd);
+}
+
+EXPORT_SYMBOL(kcopyd_client_create);
+EXPORT_SYMBOL(kcopyd_client_destroy);
+EXPORT_SYMBOL(kcopyd_copy);
+EXPORT_SYMBOL(kcopyd_cancel);
--- linux-2.4.26-rc1/drivers/md/kcopyd.h Thu Jan 1 01:00:00 1970
+++ linux/drivers/md/kcopyd.h Wed Mar 31 13:48:32 2004
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2001 Sistina Software
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_KCOPYD_H
+#define DM_KCOPYD_H
+
+/*
+ * Needed for the definition of offset_t.
+ */
+#include <linux/device-mapper.h>
+#include <linux/iobuf.h>
+
+#include "dm-io.h"
+
+int kcopyd_init(void);
+void kcopyd_exit(void);
+
+/* FIXME: make this configurable */
+#define KCOPYD_MAX_REGIONS 8
+
+#define KCOPYD_IGNORE_ERROR 1
+
+/*
+ * To use kcopyd you must first create a kcopyd client object.
+ */
+struct kcopyd_client;
+int kcopyd_client_create(unsigned int num_pages, struct kcopyd_client **result);
+void kcopyd_client_destroy(struct kcopyd_client *kc);
+
+/*
+ * Submit a copy job to kcopyd. This is built on top of the
+ * previous three fns.
+ *
+ * read_err is a boolean,
+ * write_err is a bitset, with 1 bit for each destination region
+ */
+typedef void (*kcopyd_notify_fn)(int read_err,
+ unsigned int write_err, void *context);
+
+int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from,
+ unsigned int num_dests, struct io_region *dests,
+ unsigned int flags, kcopyd_notify_fn fn, void *context);
+
+#endif
--- linux-2.4.26-rc1/include/linux/device-mapper.h Thu Jan 1 01:00:00 1970
+++ linux/include/linux/device-mapper.h Wed Mar 31 14:05:02 2004
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2001 Sistina Software (UK) Limited.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LINUX_DEVICE_MAPPER_H
+#define _LINUX_DEVICE_MAPPER_H
+
+typedef unsigned long sector_t;
+
+struct dm_target;
+struct dm_table;
+struct dm_dev;
+
+typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
+
+union map_info {
+ void *ptr;
+ unsigned long long ll;
+};
+
+/*
+ * In the constructor the target parameter will already have the
+ * table, type, begin and len fields filled in.
+ */
+typedef int (*dm_ctr_fn) (struct dm_target * target, unsigned int argc,
+ char **argv);
+
+/*
+ * The destructor doesn't need to free the dm_target, just
+ * anything hidden ti->private.
+ */
+typedef void (*dm_dtr_fn) (struct dm_target * ti);
+
+/*
+ * The map function must return:
+ * < 0: error
+ * = 0: The target will handle the io by resubmitting it later
+ * > 0: simple remap complete
+ */
+typedef int (*dm_map_fn) (struct dm_target * ti, struct buffer_head * bh,
+ int rw, union map_info *map_context);
+
+/*
+ * Returns:
+ * < 0 : error (currently ignored)
+ * 0 : ended successfully
+ * 1 : for some reason the io has still not completed (eg,
+ * multipath target might want to requeue a failed io).
+ */
+typedef int (*dm_endio_fn) (struct dm_target * ti,
+ struct buffer_head * bh, int rw, int error,
+ union map_info *map_context);
+typedef void (*dm_suspend_fn) (struct dm_target *ti);
+typedef void (*dm_resume_fn) (struct dm_target *ti);
+typedef int (*dm_status_fn) (struct dm_target * ti, status_type_t status_type,
+ char *result, unsigned int maxlen);
+
+void dm_error(const char *message);
+
+/*
+ * Constructors should call these functions to ensure destination devices
+ * are opened/closed correctly.
+ * FIXME: too many arguments.
+ */
+int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
+ sector_t len, int mode, struct dm_dev **result);
+void dm_put_device(struct dm_target *ti, struct dm_dev *d);
+
+/*
+ * Information about a target type
+ */
+struct target_type {
+ const char *name;
+ struct module *module;
+ unsigned version[3];
+ dm_ctr_fn ctr;
+ dm_dtr_fn dtr;
+ dm_map_fn map;
+ dm_endio_fn end_io;
+ dm_suspend_fn suspend;
+ dm_resume_fn resume;
+ dm_status_fn status;
+};
+
+struct dm_target {
+ struct dm_table *table;
+ struct target_type *type;
+
+ /* target limits */
+ sector_t begin;
+ sector_t len;
+
+ /* target specific data */
+ void *private;
+
+ /* Used to provide an error string from the ctr */
+ char *error;
+};
+
+int dm_register_target(struct target_type *t);
+int dm_unregister_target(struct target_type *t);
+
+#endif /* _LINUX_DEVICE_MAPPER_H */
--- linux-2.4.26-rc1/include/linux/dm-ioctl.h Thu Jan 1 01:00:00 1970
+++ linux/include/linux/dm-ioctl.h Wed Mar 31 14:06:21 2004
@@ -0,0 +1,252 @@
+/*
+ * Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LINUX_DM_IOCTL_H
+#define _LINUX_DM_IOCTL_H
+
+#include <linux/types.h>
+
+#define DM_DIR "mapper" /* Slashes not supported */
+#define DM_MAX_TYPE_NAME 16
+#define DM_NAME_LEN 128
+#define DM_UUID_LEN 129
+
+/*
+ * A traditional ioctl interface for the device mapper.
+ *
+ * Each device can have two tables associated with it, an
+ * 'active' table which is the one currently used by io passing
+ * through the device, and an 'inactive' one which is a table
+ * that is being prepared as a replacement for the 'active' one.
+ *
+ * DM_VERSION:
+ * Just get the version information for the ioctl interface.
+ *
+ * DM_REMOVE_ALL:
+ * Remove all dm devices, destroy all tables. Only really used
+ * for debug.
+ *
+ * DM_LIST_DEVICES:
+ * Get a list of all the dm device names.
+ *
+ * DM_DEV_CREATE:
+ * Create a new device, neither the 'active' or 'inactive' table
+ * slots will be filled. The device will be in suspended state
+ * after creation, however any io to the device will get errored
+ * since it will be out-of-bounds.
+ *
+ * DM_DEV_REMOVE:
+ * Remove a device, destroy any tables.
+ *
+ * DM_DEV_RENAME:
+ * Rename a device.
+ *
+ * DM_SUSPEND:
+ * This performs both suspend and resume, depending which flag is
+ * passed in.
+ * Suspend: This command will not return until all pending io to
+ * the device has completed. Further io will be deferred until
+ * the device is resumed.
+ * Resume: It is no longer an error to issue this command on an
+ * unsuspended device. If a table is present in the 'inactive'
+ * slot, it will be moved to the active slot, then the old table
+ * from the active slot will be _destroyed_. Finally the device
+ * is resumed.
+ *
+ * DM_DEV_STATUS:
+ * Retrieves the status for the table in the 'active' slot.
+ *
+ * DM_DEV_WAIT:
+ * Wait for a significant event to occur to the device. This
+ * could either be caused by an event triggered by one of the
+ * targets of the table in the 'active' slot, or a table change.
+ *
+ * DM_TABLE_LOAD:
+ * Load a table into the 'inactive' slot for the device. The
+ * device does _not_ need to be suspended prior to this command.
+ *
+ * DM_TABLE_CLEAR:
+ * Destroy any table in the 'inactive' slot (ie. abort).
+ *
+ * DM_TABLE_DEPS:
+ * Return a set of device dependencies for the 'active' table.
+ *
+ * DM_TABLE_STATUS:
+ * Return the targets status for the 'active' table.
+ */
+
+/*
+ * All ioctl arguments consist of a single chunk of memory, with
+ * this structure at the start. If a uuid is specified any
+ * lookup (eg. for a DM_INFO) will be done on that, *not* the
+ * name.
+ */
+struct dm_ioctl {
+ /*
+ * The version number is made up of three parts:
+ * major - no backward or forward compatibility,
+ * minor - only backwards compatible,
+ * patch - both backwards and forwards compatible.
+ *
+ * All clients of the ioctl interface should fill in the
+ * version number of the interface that they were
+ * compiled with.
+ *
+ * All recognised ioctl commands (ie. those that don't
+ * return -ENOTTY) fill out this field, even if the
+ * command failed.
+ */
+ uint32_t version[3]; /* in/out */
+ uint32_t data_size; /* total size of data passed in
+ * including this struct */
+
+ uint32_t data_start; /* offset to start of data
+ * relative to start of this struct */
+
+ uint32_t target_count; /* in/out */
+ int32_t open_count; /* out */
+ uint32_t flags; /* in/out */
+ uint32_t event_nr; /* in/out */
+ uint32_t padding;
+
+ uint64_t dev; /* in/out */
+
+ char name[DM_NAME_LEN]; /* device name */
+ char uuid[DM_UUID_LEN]; /* unique identifier for
+ * the block device */
+};
+
+/*
+ * Used to specify tables. These structures appear after the
+ * dm_ioctl.
+ */
+struct dm_target_spec {
+ uint64_t sector_start;
+ uint64_t length;
+ int32_t status; /* used when reading from kernel only */
+
+ /*
+ * Offset in bytes (from the start of this struct) to
+ * next target_spec.
+ */
+ uint32_t next;
+
+ char target_type[DM_MAX_TYPE_NAME];
+
+ /*
+ * Parameter string starts immediately after this object.
+ * Be careful to add padding after string to ensure correct
+ * alignment of subsequent dm_target_spec.
+ */
+};
+
+/*
+ * Used to retrieve the target dependencies.
+ */
+struct dm_target_deps {
+ uint32_t count; /* Array size */
+ uint32_t padding; /* unused */
+ uint64_t dev[0]; /* out */
+};
+
+/*
+ * Used to get a list of all dm devices.
+ */
+struct dm_name_list {
+ uint64_t dev;
+ uint32_t next; /* offset to the next record from
+ the _start_ of this */
+ char name[0];
+};
+
+/*
+ * Used to retrieve the target versions
+ */
+struct dm_target_versions {
+ uint32_t next;
+ uint32_t version[3];
+
+ char name[0];
+};
+
+/*
+ * If you change this make sure you make the corresponding change
+ * to dm-ioctl.c:lookup_ioctl()
+ */
+enum {
+ /* Top level cmds */
+ DM_VERSION_CMD = 0,
+ DM_REMOVE_ALL_CMD,
+ DM_LIST_DEVICES_CMD,
+
+ /* device level cmds */
+ DM_DEV_CREATE_CMD,
+ DM_DEV_REMOVE_CMD,
+ DM_DEV_RENAME_CMD,
+ DM_DEV_SUSPEND_CMD,
+ DM_DEV_STATUS_CMD,
+ DM_DEV_WAIT_CMD,
+
+ /* Table level cmds */
+ DM_TABLE_LOAD_CMD,
+ DM_TABLE_CLEAR_CMD,
+ DM_TABLE_DEPS_CMD,
+ DM_TABLE_STATUS_CMD,
+
+ /* Added later */
+ DM_LIST_VERSIONS_CMD,
+};
+
+#define DM_IOCTL 0xfd
+
+#define DM_VERSION _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
+#define DM_REMOVE_ALL _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
+#define DM_LIST_DEVICES _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)
+
+#define DM_DEV_CREATE _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
+#define DM_DEV_REMOVE _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
+#define DM_DEV_RENAME _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
+#define DM_DEV_SUSPEND _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
+#define DM_DEV_STATUS _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
+#define DM_DEV_WAIT _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)
+
+#define DM_TABLE_LOAD _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
+#define DM_TABLE_CLEAR _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
+#define DM_TABLE_DEPS _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
+#define DM_TABLE_STATUS _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
+
+#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
+
+#define DM_VERSION_MAJOR 4
+#define DM_VERSION_MINOR 1
+#define DM_VERSION_PATCHLEVEL 1
+#define DM_VERSION_EXTRA "-ioctl (2004-04-07)"
+
+/* Status bits */
+#define DM_READONLY_FLAG (1 << 0) /* In/Out */
+#define DM_SUSPEND_FLAG (1 << 1) /* In/Out */
+#define DM_PERSISTENT_DEV_FLAG (1 << 3) /* In */
+
+/*
+ * Flag passed into ioctl STATUS command to get table information
+ * rather than current status.
+ */
+#define DM_STATUS_TABLE_FLAG (1 << 4) /* In */
+
+/*
+ * Flags that indicate whether a table is present in either of
+ * the two table slots that a device has.
+ */
+#define DM_ACTIVE_PRESENT_FLAG (1 << 5) /* Out */
+#define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
+
+/*
+ * Indicates that the buffer passed in wasn't big enough for the
+ * results.
+ */
+#define DM_BUFFER_FULL_FLAG (1 << 8) /* Out */
+
+#endif /* _LINUX_DM_IOCTL_H */