avg e95b1e137c MFV r308987: 7180 potential race between zfs_suspend_fs+zfs_resume_fs
and zfs_ioc_rename

illumos/illumos-gate@690041b9ca
690041b9ca

https://www.illumos.org/issues/7180
  If a filesystem is not unmounted while the rename is being performed, then, for
  example, a concurrect zfs rollback may call zfs_suspend_fs followed by
  zfs_resume_fs on the same filesystem.
  The latter takes the filesystem's name as an argument. If the filesystem name
  changes as a result of the rename, then dmu_objset_hold(osname, zfsvfs, &os)
  call in zfs_resume_fs would fail resulting in a kernel panic.
  So far I have been able to reproduce this problem on FreeBSD where zfs rename
  has -u option that skips the unmounting before doing the renaming.
  But I think that in theory the same problem can occur on illumos as well,
  because the unmounting is done in userland before invoking the rename ioctl and
  there could be a race with, e.g., zfs mount.
  panic: solaris assert: dmu_objset_hold(osname, zfsvfs, &zfsvfs->z_os) == 0 (0x2
  == 0x0), file: /usr/devel/svn/head/sys/cddl/contrib/opensolaris/uts/common/fs/
  zfs/zfs_vfsops.c, line: 2210
  KDB: stack backtrace:
  db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe004df30710
  vpanic() at vpanic+0x182/frame 0xfffffe004df30790
  panic() at panic+0x43/frame 0xfffffe004df307f0
  assfail3() at assfail3+0x2c/frame 0xfffffe004df30810
  zfs_resume_fs() at zfs_resume_fs+0xb9/frame 0xfffffe004df30860
  zfs_ioc_rollback() at zfs_ioc_rollback+0x61/frame 0xfffffe004df308a0
  zfsdev_ioctl() at zfsdev_ioctl+0x65c/frame 0xfffffe004df30940
  devfs_ioctl_f() at devfs_ioctl_f+0x156/frame 0xfffffe004df309a0
  kern_ioctl() at kern_ioctl+0x246/frame 0xfffffe004df30a00
  sys_ioctl() at sys_ioctl+0x171/frame 0xfffffe004df30ae0
  amd64_syscall() at amd64_syscall+0x2db/frame 0xfffffe004df30bf0
  Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe004df30bf0

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

MFC after:	2 weeks
2016-11-24 10:21:22 +00:00
2016-11-02 06:49:25 +00:00
2016-11-22 06:28:26 +00:00
2016-11-23 10:52:19 +00:00
2016-11-22 06:28:26 +00:00
2016-11-23 16:54:27 +00:00
2016-09-29 06:19:45 +00:00
2015-04-20 20:33:22 +00:00
2015-12-31 11:21:45 +00:00
2016-09-22 13:04:03 +00:00
2016-11-20 06:10:12 +00:00

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