From c24110450650f17f7d3ba4fbe01f01ac5a115456 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 12 Aug 2010 04:13:51 +0100 Subject: [PATCH] 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 Reviewed-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- drivers/md/dm-exception-store.c | 4 +++- drivers/md/dm-exception-store.h | 3 ++- drivers/md/dm-snap.c | 36 +++++++++++++++++++-------------- 3 files changed, 26 insertions(+), 17 deletions(-) diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 2b7907b6dd09..0bdb201c2c2a 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 e8dfa06af3ba..0b2536247cf5 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 a6ab98920cc3..a1f2ab553b92 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); } -- 2.20.1