/*
- * dm-exception-store.c
- *
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
- * Copyright (C) 2006 Red Hat GmbH
+ * Copyright (C) 2006-2008 Red Hat GmbH
*
* This file is released under the GPL.
*/
-#include "dm.h"
-#include "dm-snap.h"
-#include "dm-io.h"
-#include "kcopyd.h"
+#include "dm-exception-store.h"
+#include <linux/ctype.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
-#define DM_MSG_PREFIX "snapshots"
-#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */
-
-/*-----------------------------------------------------------------
- * 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;
-};
+#define DM_MSG_PREFIX "snapshot exception stores"
-struct commit_callback {
- void (*callback)(void *, int success);
- void *context;
-};
+static LIST_HEAD(_exception_store_types);
+static DEFINE_SPINLOCK(_lock);
-/*
- * 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 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;
- struct dm_io_client *io_client;
-
- struct workqueue_struct *metadata_wq;
-};
-
-static unsigned sectors_to_pages(unsigned sectors)
-{
- return DIV_ROUND_UP(sectors, PAGE_SIZE >> 9);
-}
-
-static int alloc_area(struct pstore *ps)
+static struct dm_exception_store_type *__find_exception_store_type(const char *name)
{
- int r = -ENOMEM;
- size_t len;
+ struct dm_exception_store_type *type;
- len = ps->snap->chunk_size << SECTOR_SHIFT;
+ list_for_each_entry(type, &_exception_store_types, list)
+ if (!strcmp(name, type->name))
+ return type;
- /*
- * Allocate the chunk_size block of memory that will hold
- * a single metadata area.
- */
- ps->area = vmalloc(len);
- if (!ps->area)
- return r;
-
- return 0;
+ return NULL;
}
-static void free_area(struct pstore *ps)
+static struct dm_exception_store_type *_get_exception_store_type(const char *name)
{
- vfree(ps->area);
- ps->area = NULL;
-}
+ struct dm_exception_store_type *type;
-struct mdata_req {
- struct dm_io_region *where;
- struct dm_io_request *io_req;
- struct work_struct work;
- int result;
-};
+ spin_lock(&_lock);
-static void do_metadata(struct work_struct *work)
-{
- struct mdata_req *req = container_of(work, struct mdata_req, work);
+ type = __find_exception_store_type(name);
- req->result = dm_io(req->io_req, 1, req->where, NULL);
-}
+ if (type && !try_module_get(type->module))
+ type = NULL;
-/*
- * 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, int metadata)
-{
- struct dm_io_region where = {
- .bdev = ps->snap->cow->bdev,
- .sector = ps->snap->chunk_size * chunk,
- .count = ps->snap->chunk_size,
- };
- struct dm_io_request io_req = {
- .bi_rw = rw,
- .mem.type = DM_IO_VMA,
- .mem.ptr.vma = ps->area,
- .client = ps->io_client,
- .notify.fn = NULL,
- };
- struct mdata_req req;
-
- if (!metadata)
- return dm_io(&io_req, 1, &where, NULL);
-
- req.where = &where;
- req.io_req = &io_req;
-
- /*
- * Issue the synchronous I/O from a different thread
- * to avoid generic_make_request recursion.
- */
- INIT_WORK(&req.work, do_metadata);
- queue_work(ps->metadata_wq, &req.work);
- flush_workqueue(ps->metadata_wq);
-
- return req.result;
+ spin_unlock(&_lock);
+
+ return type;
}
/*
- * Read or write a metadata area. Remembering to skip the first
- * chunk which holds the header.
+ * get_type
+ * @type_name
+ *
+ * Attempt to retrieve the dm_exception_store_type by name. If not already
+ * available, attempt to load the appropriate module.
+ *
+ * Exstore modules are named "dm-exstore-" followed by the 'type_name'.
+ * Modules may contain multiple types.
+ * This function will first try the module "dm-exstore-<type_name>",
+ * then truncate 'type_name' on the last '-' and try again.
+ *
+ * For example, if type_name was "clustered-shared", it would search
+ * 'dm-exstore-clustered-shared' then 'dm-exstore-clustered'.
+ *
+ * 'dm-exception-store-<type_name>' is too long of a name in my
+ * opinion, which is why I've chosen to have the files
+ * containing exception store implementations be 'dm-exstore-<type_name>'.
+ * If you want your module to be autoloaded, you will follow this
+ * naming convention.
+ *
+ * Returns: dm_exception_store_type* on success, NULL on failure
*/
-static int area_io(struct pstore *ps, uint32_t area, int rw)
+static struct dm_exception_store_type *get_type(const char *type_name)
{
- 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, 0);
- if (r)
- return r;
+ char *p, *type_name_dup;
+ struct dm_exception_store_type *type;
- ps->current_area = area;
- return 0;
-}
-
-static int zero_area(struct pstore *ps, uint32_t area)
-{
- memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
- return area_io(ps, area, WRITE);
-}
+ type = _get_exception_store_type(type_name);
+ if (type)
+ return type;
-static int read_header(struct pstore *ps, int *new_snapshot)
-{
- int r;
- struct disk_header *dh;
- chunk_t chunk_size;
- int chunk_size_supplied = 1;
-
- /*
- * Use default chunk size (or hardsect_size, if larger) if none supplied
- */
- if (!ps->snap->chunk_size) {
- ps->snap->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
- bdev_hardsect_size(ps->snap->cow->bdev) >> 9);
- ps->snap->chunk_mask = ps->snap->chunk_size - 1;
- ps->snap->chunk_shift = ffs(ps->snap->chunk_size) - 1;
- chunk_size_supplied = 0;
+ type_name_dup = kstrdup(type_name, GFP_KERNEL);
+ if (!type_name_dup) {
+ DMERR("No memory left to attempt load for \"%s\"", type_name);
+ return NULL;
}
- ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap->
- chunk_size));
- if (IS_ERR(ps->io_client))
- return PTR_ERR(ps->io_client);
-
- r = alloc_area(ps);
- if (r)
- return r;
-
- r = chunk_io(ps, 0, READ, 1);
- if (r)
- goto bad;
-
- dh = (struct disk_header *) ps->area;
-
- if (le32_to_cpu(dh->magic) == 0) {
- *new_snapshot = 1;
- return 0;
- }
-
- if (le32_to_cpu(dh->magic) != SNAP_MAGIC) {
- DMWARN("Invalid or corrupt snapshot");
- r = -ENXIO;
- goto bad;
+ while (request_module("dm-exstore-%s", type_name_dup) ||
+ !(type = _get_exception_store_type(type_name))) {
+ p = strrchr(type_name_dup, '-');
+ if (!p)
+ break;
+ p[0] = '\0';
}
- *new_snapshot = 0;
- ps->valid = le32_to_cpu(dh->valid);
- ps->version = le32_to_cpu(dh->version);
- chunk_size = le32_to_cpu(dh->chunk_size);
-
- if (!chunk_size_supplied || ps->snap->chunk_size == chunk_size)
- return 0;
-
- DMWARN("chunk size %llu in device metadata overrides "
- "table chunk size of %llu.",
- (unsigned long long)chunk_size,
- (unsigned long long)ps->snap->chunk_size);
-
- /* We had a bogus chunk_size. Fix stuff up. */
- free_area(ps);
+ if (!type)
+ DMWARN("Module for exstore type \"%s\" not found.", type_name);
- ps->snap->chunk_size = chunk_size;
- ps->snap->chunk_mask = chunk_size - 1;
- ps->snap->chunk_shift = ffs(chunk_size) - 1;
+ kfree(type_name_dup);
- r = dm_io_client_resize(sectors_to_pages(ps->snap->chunk_size),
- ps->io_client);
- if (r)
- return r;
-
- r = alloc_area(ps);
- return r;
-
-bad:
- free_area(ps);
- return r;
+ return type;
}
-static int write_header(struct pstore *ps)
+static void put_type(struct dm_exception_store_type *type)
{
- struct disk_header *dh;
-
- memset(ps->area, 0, ps->snap->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->snap->chunk_size);
-
- return chunk_io(ps, 0, WRITE, 1);
+ spin_lock(&_lock);
+ module_put(type->module);
+ spin_unlock(&_lock);
}
-/*
- * Access functions for the disk exceptions, these do the endian conversions.
- */
-static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
+int dm_exception_store_type_register(struct dm_exception_store_type *type)
{
- BUG_ON(index >= ps->exceptions_per_area);
+ int r = 0;
- return ((struct disk_exception *) ps->area) + index;
-}
-
-static void read_exception(struct pstore *ps,
- uint32_t index, struct disk_exception *result)
-{
- struct disk_exception *e = get_exception(ps, index);
+ spin_lock(&_lock);
+ if (!__find_exception_store_type(type->name))
+ list_add(&type->list, &_exception_store_types);
+ else
+ r = -EEXIST;
+ spin_unlock(&_lock);
- /* copy it */
- result->old_chunk = le64_to_cpu(e->old_chunk);
- result->new_chunk = le64_to_cpu(e->new_chunk);
+ return r;
}
+EXPORT_SYMBOL(dm_exception_store_type_register);
-static void write_exception(struct pstore *ps,
- uint32_t index, struct disk_exception *de)
+int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
{
- struct disk_exception *e = get_exception(ps, index);
-
- /* copy it */
- e->old_chunk = cpu_to_le64(de->old_chunk);
- e->new_chunk = cpu_to_le64(de->new_chunk);
-}
+ spin_lock(&_lock);
-/*
- * 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++) {
- read_exception(ps, i, &de);
-
- /*
- * 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;
+ if (!__find_exception_store_type(type->name)) {
+ spin_unlock(&_lock);
+ return -EINVAL;
}
- return 0;
-}
+ list_del(&type->list);
-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;
- }
+ spin_unlock(&_lock);
return 0;
}
+EXPORT_SYMBOL(dm_exception_store_type_unregister);
-static struct pstore *get_info(struct exception_store *store)
+static int set_chunk_size(struct dm_exception_store *store,
+ const char *chunk_size_arg, char **error)
{
- 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->bdev);
-}
-
-static void persistent_destroy(struct exception_store *store)
-{
- struct pstore *ps = get_info(store);
-
- destroy_workqueue(ps->metadata_wq);
- dm_io_client_destroy(ps->io_client);
- vfree(ps->callbacks);
- free_area(ps);
- kfree(ps);
-}
-
-static int persistent_read_metadata(struct exception_store *store)
-{
- int r, uninitialized_var(new_snapshot);
- struct pstore *ps = get_info(store);
-
- /*
- * Read the snapshot header.
- */
- r = read_header(ps, &new_snapshot);
- if (r)
- return r;
-
- /*
- * Now we know correct chunk_size, complete the initialisation.
- */
- ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) /
- sizeof(struct disk_exception);
- ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
- sizeof(*ps->callbacks));
- if (!ps->callbacks)
- return -ENOMEM;
+ unsigned long chunk_size_ulong;
+ char *value;
+
+ chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
+ if (*chunk_size_arg == '\0' || *value != '\0' ||
+ chunk_size_ulong > UINT_MAX) {
+ *error = "Invalid chunk size";
+ return -EINVAL;
+ }
- /*
- * 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->version != SNAPSHOT_DISK_VERSION) {
- DMWARN("unable to handle snapshot disk version %d",
- ps->version);
- return -EINVAL;
- }
-
- /*
- * Metadata are valid, but snapshot is invalidated
- */
- if (!ps->valid)
- return 1;
-
- /*
- * Read the metadata.
- */
- r = read_exceptions(ps);
- if (r)
- return r;
+ if (!chunk_size_ulong) {
+ store->chunk_size = store->chunk_mask = store->chunk_shift = 0;
+ return 0;
}
- return 0;
+ return dm_exception_store_set_chunk_size(store,
+ (unsigned) chunk_size_ulong,
+ error);
}
-static int persistent_prepare(struct exception_store *store,
- struct dm_snap_exception *e)
+int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
+ unsigned chunk_size,
+ char **error)
{
- struct pstore *ps = get_info(store);
- uint32_t stride;
- sector_t size = get_dev_size(store->snap->cow->bdev);
+ /* Check chunk_size is a power of 2 */
+ if (!is_power_of_2(chunk_size)) {
+ *error = "Chunk size is not a power of 2";
+ return -EINVAL;
+ }
- /* Is there enough room ? */
- if (size < ((ps->next_free + 1) * store->snap->chunk_size))
- return -ENOSPC;
+ /* Validate the chunk size against the device block size */
+ if (chunk_size %
+ (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9)) {
+ *error = "Chunk size is not a multiple of device blocksize";
+ return -EINVAL;
+ }
- e->new_chunk = ps->next_free;
+ if (chunk_size > INT_MAX >> SECTOR_SHIFT) {
+ *error = "Chunk size is too high";
+ return -EINVAL;
+ }
- /*
- * 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++;
+ store->chunk_size = chunk_size;
+ store->chunk_mask = chunk_size - 1;
+ store->chunk_shift = ffs(chunk_size) - 1;
- atomic_inc(&ps->pending_count);
return 0;
}
-static void persistent_commit(struct exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context)
+int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ struct dm_snapshot *snap,
+ unsigned *args_used,
+ struct dm_exception_store **store)
{
- 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;
-
- /*
- * 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;
- }
-
- for (i = 0; i < ps->callback_count; i++) {
- cb = ps->callbacks + i;
- cb->callback(cb->context, r == 0 ? 1 : 0);
- }
-
- ps->callback_count = 0;
+ int r = 0;
+ struct dm_exception_store_type *type = NULL;
+ struct dm_exception_store *tmp_store;
+ char persistent;
+
+ if (argc < 2) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
}
-}
-static void persistent_drop(struct exception_store *store)
-{
- struct pstore *ps = get_info(store);
+ tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL);
+ if (!tmp_store) {
+ ti->error = "Exception store allocation failed";
+ return -ENOMEM;
+ }
- ps->valid = 0;
- if (write_header(ps))
- DMWARN("write header failed");
-}
+ persistent = toupper(*argv[0]);
+ if (persistent == 'P')
+ type = get_type("P");
+ else if (persistent == 'N')
+ type = get_type("N");
+ else {
+ ti->error = "Persistent flag is not P or N";
+ r = -EINVAL;
+ goto bad_type;
+ }
-int dm_create_persistent(struct exception_store *store)
-{
- struct pstore *ps;
+ if (!type) {
+ ti->error = "Exception store type not recognised";
+ r = -EINVAL;
+ goto bad_type;
+ }
- /* allocate the pstore */
- ps = kmalloc(sizeof(*ps), GFP_KERNEL);
- if (!ps)
- return -ENOMEM;
+ tmp_store->type = type;
+ tmp_store->snap = snap;
- ps->snap = store->snap;
- ps->valid = 1;
- ps->version = SNAPSHOT_DISK_VERSION;
- ps->area = NULL;
- ps->next_free = 2; /* skipping the header and first area */
- ps->current_committed = 0;
-
- ps->callback_count = 0;
- atomic_set(&ps->pending_count, 0);
- ps->callbacks = NULL;
-
- ps->metadata_wq = create_singlethread_workqueue("ksnaphd");
- if (!ps->metadata_wq) {
- kfree(ps);
- DMERR("couldn't start header metadata update thread");
- return -ENOMEM;
- }
+ r = set_chunk_size(tmp_store, argv[1], &ti->error);
+ if (r)
+ 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;
+ r = type->ctr(tmp_store, 0, NULL);
+ if (r) {
+ ti->error = "Exception store type constructor failed";
+ goto bad;
+ }
+ *args_used = 2;
+ *store = tmp_store;
return 0;
-}
-/*-----------------------------------------------------------------
- * Implementation of the store for non-persistent snapshots.
- *---------------------------------------------------------------*/
-struct transient_c {
- sector_t next_free;
-};
-
-static void transient_destroy(struct exception_store *store)
-{
- kfree(store->context);
+bad:
+ put_type(type);
+bad_type:
+ kfree(tmp_store);
+ return r;
}
+EXPORT_SYMBOL(dm_exception_store_create);
-static int transient_read_metadata(struct exception_store *store)
+void dm_exception_store_destroy(struct dm_exception_store *store)
{
- return 0;
+ store->type->dtr(store);
+ put_type(store->type);
+ kfree(store);
}
+EXPORT_SYMBOL(dm_exception_store_destroy);
-static int transient_prepare(struct exception_store *store,
- struct dm_snap_exception *e)
+int dm_exception_store_init(void)
{
- struct transient_c *tc = (struct transient_c *) store->context;
- sector_t size = get_dev_size(store->snap->cow->bdev);
+ int r;
- if (size < (tc->next_free + store->snap->chunk_size))
- return -1;
+ r = dm_transient_snapshot_init();
+ if (r) {
+ DMERR("Unable to register transient exception store type.");
+ goto transient_fail;
+ }
- e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
- tc->next_free += store->snap->chunk_size;
+ r = dm_persistent_snapshot_init();
+ if (r) {
+ DMERR("Unable to register persistent exception store type");
+ goto persistent_fail;
+ }
return 0;
-}
-
-static void transient_commit(struct exception_store *store,
- struct dm_snap_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->bdev);
+persistent_fail:
+ dm_persistent_snapshot_exit();
+transient_fail:
+ return r;
}
-int dm_create_transient(struct exception_store *store)
+void dm_exception_store_exit(void)
{
- struct transient_c *tc;
-
- store->destroy = transient_destroy;
- store->read_metadata = transient_read_metadata;
- store->prepare_exception = transient_prepare;
- store->commit_exception = transient_commit;
- store->drop_snapshot = NULL;
- store->fraction_full = transient_fraction_full;
-
- tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
- if (!tc)
- return -ENOMEM;
-
- tc->next_free = 0;
- store->context = tc;
-
- return 0;
+ dm_persistent_snapshot_exit();
+ dm_transient_snapshot_exit();
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff