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authorAlasdair G Kergon <agk@redhat.com>2005-07-12 15:53:03 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-12 16:19:10 -0700
commit436d41087d047b61f8ab0604dc74fff3240a8933 (patch)
tree46bab3a0cf02a7514b4faa5470a76326e6f8bc72 /drivers/md/dm.c
parenta044d016896d2717694003f00d31a98194077511 (diff)
downloadlinux-436d41087d047b61f8ab0604dc74fff3240a8933.tar.bz2
[PATCH] device-mapper multipath: Avoid possible suspension deadlock
To avoid deadlock when suspending a multipath device after all its paths have failed, stop queueing any I/O that is about to fail *before* calling freeze_bdev instead of after. Instead of setting a multipath 'suspended' flag which would have to be reset if an error occurs during the process, save the previous queueing state and leave userspace to restore if it wishes. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 5d40555b42ba..bb3ad79c14d7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1055,14 +1055,17 @@ int dm_suspend(struct mapped_device *md)
if (test_bit(DMF_BLOCK_IO, &md->flags))
goto out_read_unlock;
- error = __lock_fs(md);
- if (error)
- goto out_read_unlock;
-
map = dm_get_table(md);
if (map)
+ /* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
+ error = __lock_fs(md);
+ if (error) {
+ dm_table_put(map);
+ goto out_read_unlock;
+ }
+
up_read(&md->lock);
/*
@@ -1121,7 +1124,6 @@ int dm_suspend(struct mapped_device *md)
return 0;
out_unfreeze:
- /* FIXME Undo dm_table_presuspend_targets */
__unlock_fs(md);
clear_bit(DMF_BLOCK_IO, &md->flags);
out_write_unlock: