50 lines
1.9 KiB
Diff
50 lines
1.9 KiB
Diff
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From: Eric Sandeen <sandeen@sandeen.net>
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Date: Sun, 1 Aug 2010 21:33:29 +0000 (-0400)
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Subject: ext4: fix freeze deadlock under IO
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X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=437f88cc031ffe7f37f3e705367f4fe1f4be8b0f
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ext4: fix freeze deadlock under IO
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Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks
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when freezing a filesystem which had active IO; the vfs_check_frozen
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level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing
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through. Duh.
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Changing the test to FREEZE_TRANS should let the normal freeze
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syncing get through the fs, but still block any transactions from
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starting once the fs is completely frozen.
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I tested this by running fsstress in the background while periodically
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snapshotting the fs and running fsck on the result. I ran into
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occasional deadlocks, but different ones. I think this is a
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fine fix for the problem at hand, and the other deadlocky things
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will need more investigation.
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Reported-by: Phillip Susi <psusi@cfl.rr.com>
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Signed-off-by: Eric Sandeen <sandeen@redhat.com>
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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diff --git a/fs/ext4/super.c b/fs/ext4/super.c
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index e046eba..282a270 100644
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--- a/fs/ext4/super.c
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+++ b/fs/ext4/super.c
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@@ -241,7 +241,7 @@ handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
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if (sb->s_flags & MS_RDONLY)
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return ERR_PTR(-EROFS);
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- vfs_check_frozen(sb, SB_FREEZE_WRITE);
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+ vfs_check_frozen(sb, SB_FREEZE_TRANS);
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/* Special case here: if the journal has aborted behind our
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* backs (eg. EIO in the commit thread), then we still need to
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* take the FS itself readonly cleanly. */
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@@ -3608,7 +3608,7 @@ int ext4_force_commit(struct super_block *sb)
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journal = EXT4_SB(sb)->s_journal;
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if (journal) {
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- vfs_check_frozen(sb, SB_FREEZE_WRITE);
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+ vfs_check_frozen(sb, SB_FREEZE_TRANS);
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ret = ext4_journal_force_commit(journal);
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}
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