From c51c2752491e5e771de6c8861a85ba46752d7888 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Mon, 26 Jun 2006 00:27:18 -0700 Subject: [PATCH] dm snapshot: unify chunk_size Persistent snapshots currently store a private copy of the chunk size. Userspace also supplies the chunk size when loading a snapshot. Ensure consistency by only storing the chunk_size in one place instead of two. Currently the two sizes will differ if the chunk size supplied by userspace does not match the chunk size an existing snapshot actually uses. Amongst other problems, this causes an incorrect 'percentage full' to be reported. The patch ensures consistency by only storing the chunk_size in one place, removing it from struct pstore. Some initialisation is delayed until the correct chunk_size is known. If read_header() discovers that the wrong chunk size was supplied, the 'area' buffer (which the header already got read into) is reinitialised to the correct size. [akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled] Signed-off-by: Alasdair G Kergon Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/dm-snap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/md/dm-snap.c') diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 08312b4..b84bc1a 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -530,7 +530,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) } ti->private = s; - ti->split_io = chunk_size; + ti->split_io = s->chunk_size; return 0; @@ -1204,7 +1204,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result, static struct target_type origin_target = { .name = "snapshot-origin", - .version = {1, 1, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = origin_ctr, .dtr = origin_dtr, @@ -1215,7 +1215,7 @@ static struct target_type origin_target = { static struct target_type snapshot_target = { .name = "snapshot", - .version = {1, 1, 0}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, -- cgit v1.1