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Filename Latest commit message Latest commit date
Wengang Wang 9de4ffb701 ocfs2: initialize ip_next_orphan
commit f5785283dd64867a711ca1fb1f5bb172f252ecdf upstream.

Though problem if found on a lower 4.1.12 kernel, I think upstream has
same issue.

In one node in the cluster, there is the following callback trace:

   # cat /proc/21473/stack
   __ocfs2_cluster_lock.isra.36+0x336/0x9e0 [ocfs2]
   ocfs2_inode_lock_full_nested+0x121/0x520 [ocfs2]
   ocfs2_evict_inode+0x152/0x820 [ocfs2]
   evict+0xae/0x1a0
   iput+0x1c6/0x230
   ocfs2_orphan_filldir+0x5d/0x100 [ocfs2]
   ocfs2_dir_foreach_blk+0x490/0x4f0 [ocfs2]
   ocfs2_dir_foreach+0x29/0x30 [ocfs2]
   ocfs2_recover_orphans+0x1b6/0x9a0 [ocfs2]
   ocfs2_complete_recovery+0x1de/0x5c0 [ocfs2]
   process_one_work+0x169/0x4a0
   worker_thread+0x5b/0x560
   kthread+0xcb/0xf0
   ret_from_fork+0x61/0x90

The above stack is not reasonable, the final iput shouldn't happen in
ocfs2_orphan_filldir() function.  Looking at the code,

  2067         /* Skip inodes which are already added to recover list, since dio may
  2068          * happen concurrently with unlink/rename */
  2069         if (OCFS2_I(iter)->ip_next_orphan) {
  2070                 iput(iter);
  2071                 return 0;
  2072         }
  2073

The logic thinks the inode is already in recover list on seeing
ip_next_orphan is non-NULL, so it skip this inode after dropping a
reference which incremented in ocfs2_iget().

While, if the inode is already in recover list, it should have another
reference and the iput() at line 2070 should not be the final iput
(dropping the last reference).  So I don't think the inode is really in
the recover list (no vmcore to confirm).

Note that ocfs2_queue_orphans(), though not shown up in the call back
trace, is holding cluster lock on the orphan directory when looking up
for unlinked inodes.  The on disk inode eviction could involve a lot of
IOs which may need long time to finish.  That means this node could hold
the cluster lock for very long time, that can lead to the lock requests
(from other nodes) to the orhpan directory hang for long time.

Looking at more on ip_next_orphan, I found it's not initialized when
allocating a new ocfs2_inode_info structure.

This causes te reflink operations from some nodes hang for very long
time waiting for the cluster lock on the orphan directory.

Fix: initialize ip_next_orphan as NULL.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201109171746.27884-1-wen.gang.wang@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-18 19:20:30 +01:00
arch KVM: arm64: Don't hide ID registers from userspace 2020-11-18 19:20:29 +01:00
block blk-cgroup: Pre-allocate tree node on blkg_conf_prep 2020-11-10 12:37:30 +01:00
certs
crypto crypto: algif_skcipher - EBUSY on aio should be an error 2020-10-29 09:57:30 +01:00
Documentation can: j1939: swap addr and pgn in the send example 2020-11-18 19:20:19 +01:00
drivers mei: protect mei_cl_mtu from null dereference 2020-11-18 19:20:30 +01:00
fs ocfs2: initialize ip_next_orphan 2020-11-18 19:20:30 +01:00
include SUNRPC: Fix general protection fault in trace_rpc_xdr_overflow() 2020-11-18 19:20:26 +01:00
init printk: reduce LOG_BUF_SHIFT range for H8300 2020-11-05 11:43:16 +01:00
ipc
kernel reboot: fix overflow parsing reboot cpu number 2020-11-18 19:20:30 +01:00
lib random32: make prandom_u32() output unpredictable 2020-11-18 19:20:20 +01:00
LICENSES
mm mm/slub: fix panic in slab_alloc_node() 2020-11-18 19:20:30 +01:00
net cfg80211: regulatory: Fix inconsistent format argument 2020-11-18 19:20:23 +01:00
samples samples/bpf: Fix possible deadlock in xdpsock 2020-11-05 11:43:17 +01:00
scripts scripts/setlocalversion: make git describe output more reliable 2020-11-01 12:01:01 +01:00
security evm: Check size of security.evm before using it 2020-11-01 12:01:05 +01:00
sound ALSA: hda: Reinstate runtime_allow() for all hda controllers 2020-11-18 19:20:22 +01:00
tools bpf: Zero-fill re-used per-cpu map element 2020-11-18 19:20:26 +01:00
usr
virt KVM: arm64: ARM_SMCCC_ARCH_WORKAROUND_1 doesn't return SMCCC_RET_NOT_REQUIRED 2020-11-18 19:20:21 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.77 2020-11-10 21:13:20 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.