dm snapshot: extend exception store functions
Supply dm_add_exception as a callback to the read_metadata function. Add a status function ready for a later patch and name the functions consistently. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow
Alasdair G Kergon
parent
4db6bfe02b
commit
a159c1ac5f
6 changed files with 55 additions and 37 deletions
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@ -11,7 +11,6 @@
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#include <linux/pagemap.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "snapshot exception stores"
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@ -11,6 +11,7 @@
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#define _LINUX_DM_EXCEPTION_STORE
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#include <linux/blkdev.h>
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#include <linux/device-mapper.h>
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/*
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* The snapshot code deals with largish chunks of the disk at a
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@ -37,7 +38,6 @@ struct dm_snap_exception {
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* COW device).
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*/
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struct dm_exception_store {
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/*
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* Destroys this object when you've finished with it.
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*/
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@ -45,9 +45,13 @@ struct dm_exception_store {
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/*
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* The target shouldn't read the COW device until this is
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* called.
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* called. As exceptions are read from the COW, they are
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* reported back via the callback.
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*/
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int (*read_metadata) (struct dm_exception_store *store);
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int (*read_metadata) (struct dm_exception_store *store,
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int (*callback)(void *callback_context,
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chunk_t old, chunk_t new),
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void *callback_context);
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/*
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* Find somewhere to store the next exception.
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@ -68,6 +72,9 @@ struct dm_exception_store {
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*/
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void (*drop_snapshot) (struct dm_exception_store *store);
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int (*status) (struct dm_exception_store *store, status_type_t status,
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char *result, unsigned int maxlen);
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/*
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* Return how full the snapshot is.
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*/
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@ -395,7 +395,11 @@ static void write_exception(struct pstore *ps,
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* 'full' is filled in to indicate if the area has been
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* filled.
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*/
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static int insert_exceptions(struct pstore *ps, int *full)
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static int insert_exceptions(struct pstore *ps,
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int (*callback)(void *callback_context,
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chunk_t old, chunk_t new),
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void *callback_context,
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int *full)
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{
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int r;
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unsigned int i;
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@ -428,7 +432,7 @@ static int insert_exceptions(struct pstore *ps, int *full)
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/*
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* Otherwise we add the exception to the snapshot.
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*/
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r = dm_add_exception(ps->snap, de.old_chunk, de.new_chunk);
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r = callback(callback_context, de.old_chunk, de.new_chunk);
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if (r)
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return r;
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}
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@ -436,7 +440,10 @@ static int insert_exceptions(struct pstore *ps, int *full)
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return 0;
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}
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static int read_exceptions(struct pstore *ps)
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static int read_exceptions(struct pstore *ps,
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int (*callback)(void *callback_context, chunk_t old,
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chunk_t new),
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void *callback_context)
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{
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int r, full = 1;
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@ -449,7 +456,7 @@ static int read_exceptions(struct pstore *ps)
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if (r)
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return r;
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r = insert_exceptions(ps, &full);
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r = insert_exceptions(ps, callback, callback_context, &full);
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if (r)
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return r;
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}
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@ -482,7 +489,10 @@ static void persistent_destroy(struct dm_exception_store *store)
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kfree(ps);
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}
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static int persistent_read_metadata(struct dm_exception_store *store)
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static int persistent_read_metadata(struct dm_exception_store *store,
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int (*callback)(void *callback_context,
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chunk_t old, chunk_t new),
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void *callback_context)
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{
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int r, uninitialized_var(new_snapshot);
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struct pstore *ps = get_info(store);
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@ -540,7 +550,7 @@ static int persistent_read_metadata(struct dm_exception_store *store)
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/*
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* Read the metadata.
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*/
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r = read_exceptions(ps);
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r = read_exceptions(ps, callback, callback_context);
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if (r)
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return r;
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}
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@ -548,8 +558,8 @@ static int persistent_read_metadata(struct dm_exception_store *store)
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return 0;
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}
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static int persistent_prepare(struct dm_exception_store *store,
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struct dm_snap_exception *e)
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static int persistent_prepare_exception(struct dm_exception_store *store,
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struct dm_snap_exception *e)
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{
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struct pstore *ps = get_info(store);
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uint32_t stride;
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@ -575,10 +585,10 @@ static int persistent_prepare(struct dm_exception_store *store,
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return 0;
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}
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static void persistent_commit(struct dm_exception_store *store,
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struct dm_snap_exception *e,
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void (*callback) (void *, int success),
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void *callback_context)
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static void persistent_commit_exception(struct dm_exception_store *store,
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struct dm_snap_exception *e,
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void (*callback) (void *, int success),
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void *callback_context)
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{
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unsigned int i;
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struct pstore *ps = get_info(store);
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@ -637,7 +647,7 @@ static void persistent_commit(struct dm_exception_store *store,
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ps->callback_count = 0;
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}
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static void persistent_drop(struct dm_exception_store *store)
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static void persistent_drop_snapshot(struct dm_exception_store *store)
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{
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struct pstore *ps = get_info(store);
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@ -675,9 +685,9 @@ int dm_create_persistent(struct dm_exception_store *store)
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store->destroy = persistent_destroy;
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store->read_metadata = persistent_read_metadata;
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store->prepare_exception = persistent_prepare;
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store->commit_exception = persistent_commit;
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store->drop_snapshot = persistent_drop;
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store->prepare_exception = persistent_prepare_exception;
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store->commit_exception = persistent_commit_exception;
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store->drop_snapshot = persistent_drop_snapshot;
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store->fraction_full = persistent_fraction_full;
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store->context = ps;
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@ -28,13 +28,16 @@ static void transient_destroy(struct dm_exception_store *store)
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kfree(store->context);
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}
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static int transient_read_metadata(struct dm_exception_store *store)
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static int transient_read_metadata(struct dm_exception_store *store,
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int (*callback)(void *callback_context,
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chunk_t old, chunk_t new),
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void *callback_context)
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{
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return 0;
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}
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static int transient_prepare(struct dm_exception_store *store,
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struct dm_snap_exception *e)
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static int transient_prepare_exception(struct dm_exception_store *store,
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struct dm_snap_exception *e)
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{
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struct transient_c *tc = (struct transient_c *) store->context;
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sector_t size = get_dev_size(store->snap->cow->bdev);
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@ -48,10 +51,10 @@ static int transient_prepare(struct dm_exception_store *store,
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return 0;
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}
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static void transient_commit(struct dm_exception_store *store,
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struct dm_snap_exception *e,
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void (*callback) (void *, int success),
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void *callback_context)
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static void transient_commit_exception(struct dm_exception_store *store,
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struct dm_snap_exception *e,
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void (*callback) (void *, int success),
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void *callback_context)
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{
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/* Just succeed */
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callback(callback_context, 1);
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@ -70,8 +73,8 @@ int dm_create_transient(struct dm_exception_store *store)
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store->destroy = transient_destroy;
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store->read_metadata = transient_read_metadata;
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store->prepare_exception = transient_prepare;
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store->commit_exception = transient_commit;
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store->prepare_exception = transient_prepare_exception;
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store->commit_exception = transient_commit_exception;
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store->drop_snapshot = NULL;
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store->fraction_full = transient_fraction_full;
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@ -430,8 +430,13 @@ static void insert_completed_exception(struct dm_snapshot *s,
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list_add(&new_e->hash_list, e ? &e->hash_list : l);
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}
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int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
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/*
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* Callback used by the exception stores to load exceptions when
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* initialising.
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*/
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static int dm_add_exception(void *context, chunk_t old, chunk_t new)
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{
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struct dm_snapshot *s = context;
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struct dm_snap_exception *e;
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e = alloc_exception();
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@ -660,7 +665,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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spin_lock_init(&s->tracked_chunk_lock);
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/* Metadata must only be loaded into one table at once */
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r = s->store.read_metadata(&s->store);
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r = s->store.read_metadata(&s->store, dm_add_exception, (void *)s);
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if (r < 0) {
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ti->error = "Failed to read snapshot metadata";
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goto bad_load_and_register;
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@ -75,12 +75,6 @@ struct dm_snapshot {
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struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
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};
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/*
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* Used by the exception stores to load exceptions hen
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* initialising.
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*/
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int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
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/*
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* Return the number of sectors in the device.
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*/
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