• Junxiao Bi's avatar
    ocfs2: fix deadlock due to wrong locking order · f775da2f
    Junxiao Bi authored
    For commit ocfs2 journal, ocfs2 journal thread will acquire the mutex
    osb->journal->j_trans_barrier and wake up jbd2 commit thread, then it
    will wait until jbd2 commit thread done. In order journal mode, jbd2
    needs flushing dirty data pages first, and this needs get page lock.
    So osb->journal->j_trans_barrier should be got before page lock.
    
    But ocfs2_write_zero_page() and ocfs2_write_begin_inline() obey this
    locking order, and this will cause deadlock and hung the whole cluster.
    
    One deadlock catched is the following:
    
    PID: 13449  TASK: ffff8802e2f08180  CPU: 31  COMMAND: "oracle"
     #0 [ffff8802ee3f79b0] __schedule at ffffffff8150a524
     #1 [ffff8802ee3f7a58] schedule at ffffffff8150acbf
     #2 [ffff8802ee3f7a68] rwsem_down_failed_common at ffffffff8150cb85
     #3 [ffff8802ee3f7ad8] rwsem_down_read_failed at ffffffff8150cc55
     #4 [ffff8802ee3f7ae8] call_rwsem_down_read_failed at ffffffff812617a4
     #5 [ffff8802ee3f7b50] ocfs2_start_trans at ffffffffa0498919 [ocfs2]
     #6 [ffff8802ee3f7ba0] ocfs2_zero_start_ordered_transaction at ffffffffa048b2b8 [ocfs2]
     #7 [ffff8802ee3f7bf0] ocfs2_write_zero_page at ffffffffa048e9bd [ocfs2]
     #8 [ffff8802ee3f7c80] ocfs2_zero_extend_range at ffffffffa048ec83 [ocfs2]
     #9 [ffff8802ee3f7ce0] ocfs2_zero_extend at ffffffffa048edfd [ocfs2]
     #10 [ffff8802ee3f7d50] ocfs2_extend_file at ffffffffa049079e [ocfs2]
     #11 [ffff8802ee3f7da0] ocfs2_setattr at ffffffffa04910ed [ocfs2]
     #12 [ffff8802ee3f7e70] notify_change at ffffffff81187d29
     #13 [ffff8802ee3f7ee0] do_truncate at ffffffff8116bbc1
     #14 [ffff8802ee3f7f50] sys_ftruncate at ffffffff8116bcbd
     #15 [ffff8802ee3f7f80] system_call_fastpath at ffffffff81515142
        RIP: 00007f8de750c6f7  RSP: 00007fffe786e478  RFLAGS: 00000206
        RAX: 000000000000004d  RBX: ffffffff81515142  RCX: 0000000000000000
        RDX: 0000000000000200  RSI: 0000000000028400  RDI: 000000000000000d
        RBP: 00007fffe786e040   R8: 0000000000000000   R9: 000000000000000d
        R10: 0000000000000000  R11: 0000000000000206  R12: 000000000000000d
        R13: 00007fffe786e710  R14: 00007f8de70f8340  R15: 0000000000028400
        ORIG_RAX: 000000000000004d  CS: 0033  SS: 002b
    
    crash64> bt
    PID: 7610   TASK: ffff88100fd56140  CPU: 1   COMMAND: "ocfs2cmt"
     #0 [ffff88100f4d1c50] __schedule at ffffffff8150a524
     #1 [ffff88100f4d1cf8] schedule at ffffffff8150acbf
     #2 [ffff88100f4d1d08] jbd2_log_wait_commit at ffffffffa01274fd [jbd2]
     #3 [ffff88100f4d1d98] jbd2_journal_flush at ffffffffa01280b4 [jbd2]
     #4 [ffff88100f4d1dd8] ocfs2_commit_cache at ffffffffa0499b14 [ocfs2]
     #5 [ffff88100f4d1e38] ocfs2_commit_thread at ffffffffa0499d38 [ocfs2]
     #6 [ffff88100f4d1ee8] kthread at ffffffff81090db6
     #7 [ffff88100f4d1f48] kernel_thread_helper at ffffffff81516284
    
    crash64> bt
    PID: 7609   TASK: ffff88100f2d4480  CPU: 0   COMMAND: "jbd2/dm-20-86"
     #0 [ffff88100def3920] __schedule at ffffffff8150a524
     #1 [ffff88100def39c8] schedule at ffffffff8150acbf
     #2 [ffff88100def39d8] io_schedule at ffffffff8150ad6c
     #3 [ffff88100def39f8] sleep_on_page at ffffffff8111069e
     #4 [ffff88100def3a08] __wait_on_bit_lock at ffffffff8150b30a
     #5 [ffff88100def3a58] __lock_page at ffffffff81110687
     #6 [ffff88100def3ab8] write_cache_pages at ffffffff8111b752
     #7 [ffff88100def3be8] generic_writepages at ffffffff8111b901
     #8 [ffff88100def3c48] journal_submit_data_buffers at ffffffffa0120f67 [jbd2]
     #9 [ffff88100def3cf8] jbd2_journal_commit_transaction at ffffffffa0121372[jbd2]
     #10 [ffff88100def3e68] kjournald2 at ffffffffa0127a86 [jbd2]
     #11 [ffff88100def3ee8] kthread at ffffffff81090db6
     #12 [ffff88100def3f48] kernel_thread_helper at ffffffff81516284
    Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
    Cc: Mark Fasheh <mfasheh@suse.com>
    Cc: Joel Becker <jlbec@evilplan.org>
    Cc: Alex Chen <alex.chen@huawei.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    f775da2f
file.c 65 KB