lkml.org 
[lkml]   [2019]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 100/122] GFS2: Flush the GFS2 delete workqueue before stopping the kernel threads
    Date
    From: Tim Smith <tim.smith@citrix.com>

    [ Upstream commit 1eb8d7387908022951792a46fa040ad3942b3b08 ]

    Flushing the workqueue can cause operations to happen which might
    call gfs2_log_reserve(), or get stuck waiting for locks taken by such
    operations. gfs2_log_reserve() can io_schedule(). If this happens, it
    will never wake because the only thing which can wake it is gfs2_logd()
    which was already stopped.

    This causes umount of a gfs2 filesystem to wedge permanently if, for
    example, the umount immediately follows a large delete operation.

    When this occured, the following stack trace was obtained from the
    umount command

    [<ffffffff81087968>] flush_workqueue+0x1c8/0x520
    [<ffffffffa0666e29>] gfs2_make_fs_ro+0x69/0x160 [gfs2]
    [<ffffffffa0667279>] gfs2_put_super+0xa9/0x1c0 [gfs2]
    [<ffffffff811b7edf>] generic_shutdown_super+0x6f/0x100
    [<ffffffff811b7ff7>] kill_block_super+0x27/0x70
    [<ffffffffa0656a71>] gfs2_kill_sb+0x71/0x80 [gfs2]
    [<ffffffff811b792b>] deactivate_locked_super+0x3b/0x70
    [<ffffffff811b79b9>] deactivate_super+0x59/0x60
    [<ffffffff811d2998>] cleanup_mnt+0x58/0x80
    [<ffffffff811d2a12>] __cleanup_mnt+0x12/0x20
    [<ffffffff8108c87d>] task_work_run+0x7d/0xa0
    [<ffffffff8106d7d9>] exit_to_usermode_loop+0x73/0x98
    [<ffffffff81003961>] syscall_return_slowpath+0x41/0x50
    [<ffffffff815a594c>] int_ret_from_sys_call+0x25/0x8f
    [<ffffffffffffffff>] 0xffffffffffffffff

    Signed-off-by: Tim Smith <tim.smith@citrix.com>
    Signed-off-by: Mark Syms <mark.syms@citrix.com>
    Signed-off-by: Bob Peterson <rpeterso@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/gfs2/super.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
    index 8e54f2e3a3040..c3f3f1ae4e1b7 100644
    --- a/fs/gfs2/super.c
    +++ b/fs/gfs2/super.c
    @@ -845,10 +845,10 @@ static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
    if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
    return error;

    + flush_workqueue(gfs2_delete_workqueue);
    kthread_stop(sdp->sd_quotad_process);
    kthread_stop(sdp->sd_logd_process);

    - flush_workqueue(gfs2_delete_workqueue);
    gfs2_quota_sync(sdp->sd_vfs, 0);
    gfs2_statfs_sync(sdp->sd_vfs, 0);

    --
    2.20.1


    \
     
     \ /
      Last update: 2019-11-22 11:54    [W:4.124 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site