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| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-03-03 17:19:22 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-03-03 17:58:13 -0500 |
| commit | 2c945820cab96ebf265598d998e63ef22393d0d4 (patch) | |
| tree | bf738c96d1c98f6743abfcf4312449d9e021140d | |
| parent | c64d240df31513522901539a3206a41e9e6d00c8 (diff) | |
| download | backlight-2c945820cab96ebf265598d998e63ef22393d0d4.tar.gz | |
dm snapshot: fix metadata corruption
Commit 55494bf2947dccdf2 ("dm snapshot: use dm-bufio") broke snapshots.
Before that 3.14-rc1 commit, loading a snapshot's list of exceptions
involved reading exception areas one by one into ps->area and inserting
those exceptions into the hash table. Commit 55494bf2947dccdf2 changed
it so that dm-bufio with prefetch is used to load exceptions in batchs.
Exceptions are loaded correctly, but ps->area is left uninitialized.
When a new exception is allocated, it is stored in this uninitialized
ps->area which will be written to the disk. This causes metadata
corruption.
Fix this corruption by copying the last area that was read via dm-bufio
into ps->area.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| -rw-r--r-- | drivers/md/dm-snap-persistent.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index afc3d017de4c6a..d6e88178d22cff 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -546,6 +546,9 @@ static int read_exceptions(struct pstore *ps, r = insert_exceptions(ps, area, callback, callback_context, &full); + if (!full) + memcpy(ps->area, area, ps->store->chunk_size << SECTOR_SHIFT); + dm_bufio_release(bp); dm_bufio_forget(client, chunk); |