tree 89700a88b07f2389e9072b83875220442c1afa98
parent e75ed71be4f2f7508bd7d1d993d34095a10ca447
author piaojun <piaojun@huawei.com> 1517444132 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1517447915 -0800

ocfs2: return error when we attempt to access a dirty bh in jbd2

We should not reuse the dirty bh in jbd2 directly due to the following
situation:

1. When removing extent rec, we will dirty the bhs of extent rec and
   truncate log at the same time, and hand them over to jbd2.

2. The bhs are submitted to jbd2 area successfully.

3. The write-back thread of device help flush the bhs to disk but
   encounter write error due to abnormal storage link.

4. After a while the storage link become normal. Truncate log flush
   worker triggered by the next space reclaiming found the dirty bh of
   truncate log and clear its 'BH_Write_EIO' and then set it uptodate in
   __ocfs2_journal_access():

   ocfs2_truncate_log_worker
     ocfs2_flush_truncate_log
       __ocfs2_flush_truncate_log
         ocfs2_replay_truncate_records
           ocfs2_journal_access_di
             __ocfs2_journal_access // here we clear io_error and set 'tl_bh' uptodata.

5. Then jbd2 will flush the bh of truncate log to disk, but the bh of
   extent rec is still in error state, and unfortunately nobody will
   take care of it.

6. At last the space of extent rec was not reduced, but truncate log
   flush worker have given it back to globalalloc. That will cause
   duplicate cluster problem which could be identified by fsck.ocfs2.

Sadly we can hardly revert this but set fs read-only in case of ruining
atomicity and consistency of space reclaim.

Link: http://lkml.kernel.org/r/5A6E8092.8090701@huawei.com
Fixes: acf8fdbe6afb ("ocfs2: do not BUG if buffer not uptodate in __ocfs2_journal_access")
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>