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| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-10-16 23:18:16 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-10-16 23:18:16 +0100 |
| commit | 4c6fff445d7aa753957856278d4d93bcad6e2c14 (patch) | |
| tree | 56ac3d262699fe5a42f76fe9f992277a6a7a2934 /drivers/md/dm-snap.c | |
| parent | 0e8c4e4e3ebb15756ddc4170a88149a2cd323cfe (diff) | |
| download | linux-4c6fff445d7aa753957856278d4d93bcad6e2c14.tar.bz2 | |
dm snapshot: lock snapshot while supplying status
This patch locks the snapshot when returning status. It fixes a race
when it could return an invalid number of free chunks if someone
was simultaneously modifying it.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 9cb392b3e920..9bc814aa2bbd 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1152,6 +1152,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, unsigned sz = 0; struct dm_snapshot *snap = ti->private; + down_write(&snap->lock); + switch (type) { case STATUSTYPE_INFO: if (!snap->valid) @@ -1183,6 +1185,8 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, break; } + up_write(&snap->lock); + return 0; } |