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authorEric Sandeen <sandeen@sandeen.net>2010-08-01 17:33:29 -0400
committerTheodore Ts'o <tytso@mit.edu>2010-08-01 17:33:29 -0400
commit437f88cc031ffe7f37f3e705367f4fe1f4be8b0f (patch)
tree0b3ab55db25c0ac8695b27858013388ff4bcc8a9 /fs
parent4538821993f4486c76090dfb377c60c0a0e71ba3 (diff)
ext4: fix freeze deadlock under IO
Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks when freezing a filesystem which had active IO; the vfs_check_frozen level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing through. Duh. Changing the test to FREEZE_TRANS should let the normal freeze syncing get through the fs, but still block any transactions from starting once the fs is completely frozen. I tested this by running fsstress in the background while periodically snapshotting the fs and running fsck on the result. I ran into occasional deadlocks, but different ones. I think this is a fine fix for the problem at hand, and the other deadlocky things will need more investigation. Reported-by: Phillip Susi <psusi@cfl.rr.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/super.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e046eba24782..282a2704be23 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -241,7 +241,7 @@ handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
241 if (sb->s_flags & MS_RDONLY) 241 if (sb->s_flags & MS_RDONLY)
242 return ERR_PTR(-EROFS); 242 return ERR_PTR(-EROFS);
243 243
244 vfs_check_frozen(sb, SB_FREEZE_WRITE); 244 vfs_check_frozen(sb, SB_FREEZE_TRANS);
245 /* Special case here: if the journal has aborted behind our 245 /* Special case here: if the journal has aborted behind our
246 * backs (eg. EIO in the commit thread), then we still need to 246 * backs (eg. EIO in the commit thread), then we still need to
247 * take the FS itself readonly cleanly. */ 247 * take the FS itself readonly cleanly. */
@@ -3608,7 +3608,7 @@ int ext4_force_commit(struct super_block *sb)
3608 3608
3609 journal = EXT4_SB(sb)->s_journal; 3609 journal = EXT4_SB(sb)->s_journal;
3610 if (journal) { 3610 if (journal) {
3611 vfs_check_frozen(sb, SB_FREEZE_WRITE); 3611 vfs_check_frozen(sb, SB_FREEZE_TRANS);
3612 ret = ext4_journal_force_commit(journal); 3612 ret = ext4_journal_force_commit(journal);
3613 } 3613 }
3614 3614