| From 6b567dac801c672424588db1f79d72ab125b2d81 Mon Sep 17 00:00:00 2001 |
| From: Eric Sandeen <sandeen@sandeen.net> |
| Date: Sun, 1 Aug 2010 17:33:29 -0400 |
| Subject: [PATCH] ext4: fix freeze deadlock under IO |
| |
| commit 437f88cc031ffe7f37f3e705367f4fe1f4be8b0f upstream. |
| [The 6b0310fb below references the mainline version of what |
| has also been cherry picked into this 34-stable branch] |
| |
| 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| fs/ext4/super.c | 4 ++-- |
| 1 files changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/fs/ext4/super.c b/fs/ext4/super.c |
| index 2aa9314..cd35e34 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. */ |
| @@ -3485,7 +3485,7 @@ 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); |
| } |
| |
| -- |
| 1.7.0.4 |
| |
