kernel/ext4-fix-freeze-deadlock-under-io.patch
Chuck Ebbert be1655172b - Linux 2.6.32.18
- Backport nouveau noaccel fix for nva3+ cards from f13.
- ext4-fix-freeze-deadlock-under-io.patch:
  Fix deadlock caused by patch in 2.6.32.17
  (0036-ext4-don-t-return-to-userspace-after-freezing-the-fs.patch)
2010-08-10 16:07:52 -04:00

50 lines
1.9 KiB
Diff

From: Eric Sandeen <sandeen@sandeen.net>
Date: Sun, 1 Aug 2010 21:33:29 +0000 (-0400)
Subject: ext4: fix freeze deadlock under IO
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=437f88cc031ffe7f37f3e705367f4fe1f4be8b0f
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>
---
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e046eba..282a270 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)
if (sb->s_flags & MS_RDONLY)
return ERR_PTR(-EROFS);
- vfs_check_frozen(sb, SB_FREEZE_WRITE);
+ vfs_check_frozen(sb, SB_FREEZE_TRANS);
/* Special case here: if the journal has aborted behind our
* backs (eg. EIO in the commit thread), then we still need to
* take the FS itself readonly cleanly. */
@@ -3608,7 +3608,7 @@ int ext4_force_commit(struct super_block *sb)
journal = EXT4_SB(sb)->s_journal;
if (journal) {
- vfs_check_frozen(sb, SB_FREEZE_WRITE);
+ vfs_check_frozen(sb, SB_FREEZE_TRANS);
ret = ext4_journal_force_commit(journal);
}