Commit b253bfd8 authored Jun 23, 2014 by Xue jiufei Committed by Linus Torvalds Jun 23, 2014

ocfs2: revert "ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously"



75f82eaa ("ocfs2: fix NULL pointer dereference when dismount and
ocfs2rec simultaneously") may cause umount hang while shutting down
truncate log.

The situation is as followes:
ocfs2_dismout_volume
-> ocfs2_recovery_exit
  -> free osb->recovery_map
-> ocfs2_truncate_shutdown
  -> lock global bitmap inode
    -> ocfs2_wait_for_recovery
          -> check whether osb->recovery_map->rm_used is zero

Because osb->recovery_map is already freed, rm_used can be any other
values, so it may yield umount hang.

Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 27bf6305

fs/ocfs2/super.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -1925,15 +1925,11 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)

		ocfs2_shutdown_local_alloc(osb);

		ocfs2_truncate_log_shutdown(osb);

		/* This will disable recovery and flush any recovery work. */
		ocfs2_recovery_exit(osb);

		/*
		* During dismount, when it recovers another node it will call
		* ocfs2_recover_orphans and queue delayed work osb_truncate_log_wq.
		*/
		ocfs2_truncate_log_shutdown(osb);

		ocfs2_journal_shutdown(osb);

		ocfs2_sync_blockdev(sb);

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