diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-12-10 23:51:53 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-10 23:51:53 +0000 |
| commit | 94e76572b5dd37b1f0f4b3742ee8a565daead932 (patch) | |
| tree | 2e7737f21d99a881b7a2d0977adad1d2bd9bfb87 | |
| parent | d2bb7df8cac647b92f51fb84ae735771e7adbfa7 (diff) | |
dm snapshot: only take lock for statustype info not table
Take snapshot lock only for STATUSTYPE_INFO, not STATUSTYPE_TABLE.
Commit 4c6fff445d7aa753957856278d4d93bcad6e2c14
(dm-snapshot-lock-snapshot-while-supplying-status.patch)
introduced this use of the lock, but userspace applications using
libdevmapper have been found to request STATUSTYPE_TABLE while the device
is suspended and the lock is already held, leading to deadlock. Since
the lock is not necessary in this case, don't try to take it.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
| -rw-r--r-- | drivers/md/dm-snap.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 3a3ba46e6d4..d135212958f 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1152,10 +1152,11 @@ 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: + + down_write(&snap->lock); + if (!snap->valid) DMEMIT("Invalid"); else { @@ -1171,6 +1172,9 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, else DMEMIT("Unknown"); } + + up_write(&snap->lock); + break; case STATUSTYPE_TABLE: @@ -1185,8 +1189,6 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, break; } - up_write(&snap->lock); - return 0; } |