linux/net/ceph
Ilya Dryomov 88bc1922c2 libceph: defer __complete_request() to a workqueue
In the common case, req->r_callback is called by handle_reply() on the
ceph-msgr worker thread without any locks.  If handle_reply() fails, it
is called with both osd->lock and osdc->lock.  In the map check case,
it is called with just osdc->lock but held for write.  Finally, if the
request is aborted because of -ENOSPC or by ceph_osdc_abort_requests(),
it is called directly on the submitter's thread, again with both locks.

req->r_callback on the submitter's thread is relatively new (introduced
in 4.12) and ripe for deadlocks -- e.g. writeback worker thread waiting
on itself:

  inode_wait_for_writeback+0x26/0x40
  evict+0xb5/0x1a0
  iput+0x1d2/0x220
  ceph_put_wrbuffer_cap_refs+0xe0/0x2c0 [ceph]
  writepages_finish+0x2d3/0x410 [ceph]
  __complete_request+0x26/0x60 [libceph]
  complete_request+0x2e/0x70 [libceph]
  __submit_request+0x256/0x330 [libceph]
  submit_request+0x2b/0x30 [libceph]
  ceph_osdc_start_request+0x25/0x40 [libceph]
  ceph_writepages_start+0xdfe/0x1320 [ceph]
  do_writepages+0x1f/0x70
  __writeback_single_inode+0x45/0x330
  writeback_sb_inodes+0x26a/0x600
  __writeback_inodes_wb+0x92/0xc0
  wb_writeback+0x274/0x330
  wb_workfn+0x2d5/0x3b0

Defer __complete_request() to a workqueue in all failure cases so it's
never on the same thread as ceph_osdc_start_request() and always called
with no locks held.

Link: http://tracker.ceph.com/issues/23978
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
2018-06-04 20:45:58 +02:00
..
crush License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
armor.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_none.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_none.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_x_protocol.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_x.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth_x.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
auth.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
buffer.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ceph_common.c The big ticket items are: 2018-04-10 12:25:30 -07:00
ceph_fs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ceph_hash.c ceph: mark expected switch fall-throughs 2017-11-13 12:11:39 +01:00
ceph_strings.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cls_lock_client.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto.c libceph, ceph: add __init attribution to init funcitons 2018-04-02 10:12:48 +02:00
crypto.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs.c libceph, ceph: add __init attribution to init funcitons 2018-04-02 10:12:48 +02:00
Kconfig libceph: select CRYPTO_CBC in addition to CRYPTO_AES 2014-10-14 21:03:20 +04:00
Makefile libceph: striping framework implementation 2018-04-02 10:12:42 +02:00
messenger.c libceph: use MSG_TRUNC for discarding received bytes 2018-06-04 20:45:55 +02:00
mon_client.c libceph: reschedule a tick in finish_hunting() 2018-04-24 10:40:21 +02:00
msgpool.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
osd_client.c libceph: defer __complete_request() to a workqueue 2018-06-04 20:45:58 +02:00
osdmap.c libceph, ceph: move ceph_calc_file_object_mapping() to striper.c 2018-04-02 10:12:43 +02:00
pagelist.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pagevec.c Merge branch 'work.get_user_pages_fast' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:38:51 -08:00
snapshot.c libceph: convert ceph_snap_context.nref from atomic_t to refcount_t 2017-05-04 09:19:18 +02:00
string_table.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
striper.c libceph, ceph: move ceph_calc_file_object_mapping() to striper.c 2018-04-02 10:12:43 +02:00