On Thu, Jun 23, 2022 at 01:40:01PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > While running the following fstest with logged xattrs DISabled, I > noticed the following: > > # FSSTRESS_AVOID="-z -f unlink=1 -f rmdir=1 -f creat=2 -f mkdir=2 -f > getfattr=3 -f listfattr=3 -f attr_remove=4 -f removefattr=4 -f > setfattr=20 -f attr_set=60" ./check generic/475 > > INFO: task u9:1:40 blocked for more than 61 seconds. > Tainted: G O 5.19.0-rc2-djwx #rc2 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:u9:1 state:D stack:12872 pid: 40 ppid: 2 flags:0x00004000 > Workqueue: xfs-cil/dm-0 xlog_cil_push_work [xfs] > Call Trace: > <TASK> > __schedule+0x2db/0x1110 > schedule+0x58/0xc0 > schedule_timeout+0x115/0x160 > __down_common+0x126/0x210 > down+0x54/0x70 > xfs_buf_lock+0x2d/0xe0 [xfs 0532c1cb1d67dd81d15cb79ac6e415c8dec58f73] > xfs_buf_item_unpin+0x227/0x3a0 [xfs 0532c1cb1d67dd81d15cb79ac6e415c8dec58f73] > xfs_trans_committed_bulk+0x18e/0x320 [xfs 0532c1cb1d67dd81d15cb79ac6e415c8dec58f73] > xlog_cil_committed+0x2ea/0x360 [xfs 0532c1cb1d67dd81d15cb79ac6e415c8dec58f73] > xlog_cil_push_work+0x60f/0x690 [xfs 0532c1cb1d67dd81d15cb79ac6e415c8dec58f73] > process_one_work+0x1df/0x3c0 > worker_thread+0x53/0x3b0 > kthread+0xea/0x110 > ret_from_fork+0x1f/0x30 > </TASK> > > This appears to be the result of shortform_to_leaf creating a new leaf > buffer as part of adding an xattr to a file. The new leaf buffer is > held and attached to the xfs_attr_intent structure, but then the > filesystem shuts down. Instead of the usual path (which adds the attr > to the held leaf buffer which releases the hold), we instead cancel the > entire deferred operation. > > Unfortunately, xfs_attr_cancel_item doesn't release any attached leaf > buffers, so we leak the locked buffer. The CIL cannot do anything > about that, and hangs. Fix this by teaching it to release leaf buffers, > and make XFS a little more careful about not leaving a dangling > reference. > > The prologue of xfs_attri_item_recover is (in this author's opinion) a > little hard to figure out, so I'll clean that up in the next patch. > > Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> > --- > fs/xfs/xfs_attr_item.c | 20 +++++++++++++++++++- > 1 file changed, 19 insertions(+), 1 deletion(-) Looks fine. Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> -- Dave Chinner david@xxxxxxxxxxxxx
