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authorJiufei Xue <xuejiufei@huawei.com>2016-03-15 14:53:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-15 16:55:16 -0700
commit814ce69432bffdd0533fda28deea5dcfba153d17 (patch)
tree9cc76feac9406d03644c030354566a6ef4970276 /block
parentd277f33eda000ca03b1497fcf1c9e2ec33adf4c6 (diff)
downloadlwn-814ce69432bffdd0533fda28deea5dcfba153d17.tar.gz
lwn-814ce69432bffdd0533fda28deea5dcfba153d17.zip
ocfs2: fix a tiny race that leads file system read-only
when o2hb detect a node down, it first set the dead node to recovery map and create ocfs2rec which will replay journal for dead node. o2hb thread then call dlm_do_local_recovery_cleanup() to delete the lock for dead node. After the lock of dead node is gone, locks for other nodes can be granted and may modify the meta data without replaying journal of the dead node. The detail is described as follows. N1 N2 N3(master) modify the extent tree of inode, and commit dirty metadata to journal, then goes down. o2hb thread detects N1 goes down, set recovery map and delete the lock of N1. dlm_thread flush ast for the lock of N2. do not detect the death of N1, so recovery map is empty. read inode from disk without replaying the journal of N1 and modify the extent tree of the inode that N1 had modified. ocfs2rec recover the journal of N1. The modification of N2 is lost. The modification of N1 and N2 are not serial, and it will lead to read-only file system. We can set recovery_waiting flag to the lock resource after delete the lock for dead node to prevent other node from getting the lock before dlm recovery. After dlm recovery, the recovery map on N2 is not empty, ocfs2_inode_lock_full_nested() will wait for ocfs2 recovery. Signed-off-by: Jiufei Xue <xuejiufei@huawei.com> Reviewed-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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