Patch series "rewrite error handling during mounting stage".
This patch (of 5):
After commit da5e7c8782 ("ocfs2: cleanup journal init and shutdown"),
journal init later than before, it makes NULL pointer access in free
routine.
Crash flow:
ocfs2_fill_super
+ ocfs2_mount_volume
| + ocfs2_dlm_init //fail & return, osb->journal is NULL.
| + ...
| + ocfs2_check_volume //no chance to init osb->journal
|
+ ...
+ ocfs2_dismount_volume
ocfs2_release_system_inodes
...
evict
...
ocfs2_clear_inode
ocfs2_checkpoint_inode
ocfs2_ci_fully_checkpointed
time_after(journal->j_trans_id, ci->ci_last_trans)
+ journal is empty, crash!
For fixing, there are three solutions:
1> Partly revert commit da5e7c8782
For avoiding kernel crash, this make sense for us. We only
concerned whether there has any non-system inode access before dlm
init. The answer is NO. And all journal replay/recovery handling
happen after dlm & journal init done. So this method is not graceful
but workable.
2> Add osb->journal check in free inode routine (eg ocfs2_clear_inode)
The fix code is special for mounting phase, but it will continue
working after mounting stage. In another word, this method adds
useless code in normal inode free flow.
3> Do directly free inode in mounting phase
This method is brutal/complex and may introduce unsafe code,
currently maintainer didn't like.
At last, we chose method <1> and did partly reverted job. We reverted
journal init codes, and kept cleanup codes flow.
Link: https://lkml.kernel.org/r/20220424130952.2436-1-heming.zhao@suse.com
Link: https://lkml.kernel.org/r/20220424130952.2436-2-heming.zhao@suse.com
Fixes: da5e7c8782 ("ocfs2: cleanup journal init and shutdown")
Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
bb20b31dee