mirror_zfs/include
Brian Behlendorf 6857950e46 Fix zpl_mount() deadlock
Commit 93b43af10 inadvertently introduced the following scenario which
can result in a deadlock.  This issue was most easily reproduced by
LXD containers using a ZFS storage backend but should be reproducible
under any workload which is frequently mounting and unmounting.

-- THREAD A --
spa_sync()
  spa_sync_upgrades()
    rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); <- Waiting on B

-- THREAD B --
mount_fs()
  zpl_mount()
    zpl_mount_impl()
      dmu_objset_hold()
        dmu_objset_hold_flags()
          dsl_pool_hold()
            dsl_pool_config_enter()
              rrw_enter(&dp->dp_config_rwlock, RW_READER, tag);
    sget()
      sget_userns()
        grab_super()
          down_write(&s->s_umount); <- Waiting on C

-- THREAD C --
cleanup_mnt()
  deactivate_super()
    down_write(&s->s_umount);
    deactivate_locked_super()
      zpl_kill_sb()
        kill_anon_super()
          generic_shutdown_super()
            sync_filesystem()
              zpl_sync_fs()
                zfs_sync()
                  zil_commit()
                    txg_wait_synced() <- Waiting on A

Reviewed by: Alek Pinchuk <apinchuk@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7598 
Closes #7659 
Closes #7691 
Closes #7693
2018-07-06 02:46:51 -07:00
..
linux Linux 4.14 compat: blk_queue_stackable() 2018-07-06 02:46:51 -07:00
sys Fix zpl_mount() deadlock 2018-07-06 02:46:51 -07:00
libnvpair.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil_common.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil.h Correct cppcheck errors (#6662) 2017-09-20 12:59:21 -07:00
libzfs_core.h OpenZFS 7600 - zfs rollback should pass target snapshot to kernel 2017-07-04 15:29:52 -07:00
libzfs_impl.h Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
libzfs.h Add pool state /proc entry, "SUSPENDED" pools 2018-07-06 02:46:51 -07:00
Makefile.am Kernel header installation should respect --prefix 2014-10-28 09:37:06 -07:00
zfeature_common.h OpenZFS 2932 - support crash dumps to raidz, etc. pools 2017-04-10 10:24:17 -07:00
zfs_comutil.h Illumos #2882, #2883, #2900 2013-09-04 15:49:00 -07:00
zfs_deleg.h Add support for user/group dnode accounting & quota 2016-10-07 09:45:13 -07:00
zfs_fletcher.h DLPX-44812 integrate EP-220 large memory scalability 2016-11-29 14:34:27 -08:00
zfs_namecheck.h OpenZFS 7386 - zfs get does not work properly with bookmarks 2017-01-26 14:42:15 -08:00
zfs_prop.h Check the dataset type more rigorously when fetching properties. 2014-05-06 10:41:46 -07:00
zpios-ctl.h Fix spelling 2017-01-03 11:31:18 -06:00
zpios-internal.h Fix spelling 2017-01-03 11:31:18 -06:00