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Commit d4edac31 authored by Josef Bacik's avatar Josef Bacik Committed by Theodore Ts'o
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ext4: wait for log to commit when umounting 



There is a potential race when a transaction is committing right when
the file system is being umounting.  This could reduce in a race
because EXT4_SB(sb)->s_group_info could be freed in ext4_put_super
before the commit code calls a callback so the mballoc code can
release freed blocks in the transaction, resulting in a panic trying
to access the freed s_group_info.

The fix is to wait for the transaction to finish committing before we
shutdown the multiblock allocator.  

Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent b9a4207d

fs/ext4/super.c

+6 −4
Original line number Original line Diff line number Diff line
@@ -603,10 +603,6 @@ static void ext4_put_super(struct super_block *sb) 
	if (sb->s_dirt)

	if (sb->s_dirt)

		ext4_commit_super(sb, 1);

		ext4_commit_super(sb, 1);





	ext4_release_system_zone(sb);

	ext4_mb_release(sb);

	ext4_ext_release(sb);

	ext4_xattr_put_super(sb);

	if (sbi->s_journal) {

	if (sbi->s_journal) {

		err = jbd2_journal_destroy(sbi->s_journal);

		err = jbd2_journal_destroy(sbi->s_journal);

		sbi->s_journal = NULL;

		sbi->s_journal = NULL;
@@ -614,6 +610,12 @@ static void ext4_put_super(struct super_block *sb) 
			ext4_abort(sb, __func__,

			ext4_abort(sb, __func__,

				   "Couldn't clean up the journal");

				   "Couldn't clean up the journal");

	}

	}



	ext4_release_system_zone(sb);

	ext4_mb_release(sb);

	ext4_ext_release(sb);

	ext4_xattr_put_super(sb);



	if (!(sb->s_flags & MS_RDONLY)) {

	if (!(sb->s_flags & MS_RDONLY)) {

		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);

		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);

		es->s_state = cpu_to_le16(sbi->s_mount_state);

		es->s_state = cpu_to_le16(sbi->s_mount_state);