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authorMikulas Patocka <mpatocka@redhat.com>2010-08-12 04:13:51 +0100
committerAlasdair G Kergon <agk@redhat.com>2010-08-12 04:13:51 +0100
commitc24110450650f17f7d3ba4fbe01f01ac5a115456 (patch)
tree8b5bff17f77c995099d93b2b4a32bc306962a0bf
parent1e5554c8428bc7209a83e2d07ca724be4d981ce3 (diff)
downloadop-kernel-dev-c24110450650f17f7d3ba4fbe01f01ac5a115456.zip
op-kernel-dev-c24110450650f17f7d3ba4fbe01f01ac5a115456.tar.gz
dm snapshot: test chunk size against both origin and snapshot
Validate chunk size against both origin and snapshot sector size Don't allow chunk size smaller than either origin or snapshot logical sector size. Reading or writing data not aligned to sector size is not allowed and causes immediate errors. This requires us to open the origin before initialising the exception store and to export dm_snap_origin. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm-exception-store.c4
-rw-r--r--drivers/md/dm-exception-store.h3
-rw-r--r--drivers/md/dm-snap.c36
3 files changed, 26 insertions, 17 deletions
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 2b7907b..0bdb201 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -173,7 +173,9 @@ int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
/* Validate the chunk size against the device block size */
if (chunk_size %
- (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9)) {
+ (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9) ||
+ chunk_size %
+ (bdev_logical_block_size(dm_snap_origin(store->snap)->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index e8dfa06..0b25362 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -126,8 +126,9 @@ struct dm_exception_store {
};
/*
- * Obtain the cow device used by a given snapshot.
+ * Obtain the origin or cow device used by a given snapshot.
*/
+struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
/*
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a6ab989..a1f2ab5 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -148,6 +148,12 @@ struct dm_snapshot {
#define RUNNING_MERGE 0
#define SHUTDOWN_MERGE 1
+struct dm_dev *dm_snap_origin(struct dm_snapshot *s)
+{
+ return s->origin;
+}
+EXPORT_SYMBOL(dm_snap_origin);
+
struct dm_dev *dm_snap_cow(struct dm_snapshot *s)
{
return s->cow;
@@ -1065,10 +1071,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
origin_mode = FMODE_WRITE;
}
- origin_path = argv[0];
- argv++;
- argc--;
-
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s) {
ti->error = "Cannot allocate snapshot context private "
@@ -1077,6 +1079,16 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
+ origin_path = argv[0];
+ argv++;
+ argc--;
+
+ r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
+ if (r) {
+ ti->error = "Cannot get origin device";
+ goto bad_origin;
+ }
+
cow_path = argv[0];
argv++;
argc--;
@@ -1097,12 +1109,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
argv += args_used;
argc -= args_used;
- r = dm_get_device(ti, origin_path, origin_mode, &s->origin);
- if (r) {
- ti->error = "Cannot get origin device";
- goto bad_origin;
- }
-
s->ti = ti;
s->valid = 1;
s->active = 0;
@@ -1212,15 +1218,15 @@ bad_kcopyd:
dm_exception_table_exit(&s->complete, exception_cache);
bad_hash_tables:
- dm_put_device(ti, s->origin);
-
-bad_origin:
dm_exception_store_destroy(s->store);
bad_store:
dm_put_device(ti, s->cow);
bad_cow:
+ dm_put_device(ti, s->origin);
+
+bad_origin:
kfree(s);
bad:
@@ -1314,12 +1320,12 @@ static void snapshot_dtr(struct dm_target *ti)
mempool_destroy(s->pending_pool);
- dm_put_device(ti, s->origin);
-
dm_exception_store_destroy(s->store);
dm_put_device(ti, s->cow);
+ dm_put_device(ti, s->origin);
+
kfree(s);
}
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