linux.git/fs/aio.c, branch v4.13 Linux kernel source tree fs: add O_DIRECT and aio support for sending down write life time hints 2017-06-27T18:05:36+00:00 Jens Axboe axboe@kernel.dk 2017-06-27T17:01:22+00:00 45d06cf701a3866e0d246789039a46370af60223 Reviewed-by: Andreas Dilger <adilger@dilger.ca> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs: Introduce RWF_NOWAIT and FMODE_AIO_NOWAIT 2017-06-20T13:12:03+00:00 Goldwyn Rodrigues rgoldwyn@suse.com 2017-06-20T12:05:43+00:00 b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e RWF_NOWAIT informs kernel to bail out if an AIO request will block for reasons such as file allocations, or a writeback triggered, or would block while allocating requests while performing direct I/O. RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags. FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable of returning -EAGAIN if the AIO call will block. This must be set by supporting filesystems in the ->open() call. Filesystems xfs, btrfs and ext4 would be supported in the following patches. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
RWF_NOWAIT informs kernel to bail out if an AIO request will block
for reasons such as file allocations, or a writeback triggered,
or would block while allocating requests while performing
direct I/O.

RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags.

FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable
of returning -EAGAIN if the AIO call will block. This must be set by
supporting filesystems in the ->open() call.

Filesystems xfs, btrfs and ext4 would be supported in the following patches.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs: Use RWF_* flags for AIO operations 2017-06-20T13:12:03+00:00 Goldwyn Rodrigues rgoldwyn@suse.com 2017-06-20T12:05:42+00:00 9830f4be159b29399d107bffb99e0132bc5aedd4 aio_rw_flags is introduced in struct iocb (using aio_reserved1) which will carry the RWF_* flags. We cannot use aio_flags because they are not checked for validity which may break existing applications. Note, the only place RWF_HIPRI comes in effect is dio_await_one(). All the rest of the locations, aio code return -EIOCBQUEUED before the checks for RWF_HIPRI. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
aio_rw_flags is introduced in struct iocb (using aio_reserved1) which will
carry the RWF_* flags. We cannot use aio_flags because they are not
checked for validity which may break existing applications.

Note, the only place RWF_HIPRI comes in effect is dio_await_one().
All the rest of the locations, aio code return -EIOCBQUEUED before the
checks for RWF_HIPRI.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03T18:16:38+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-03-03T18:16:38+00:00 1827adb11ad26b2290dc9fe2aaf54976b2439865 Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ... 
Pull sched.h split-up from Ingo Molnar:
 "The point of these changes is to significantly reduce the
  <linux/sched.h> header footprint, to speed up the kernel build and to
  have a cleaner header structure.

  After these changes the new <linux/sched.h>'s typical preprocessed
  size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
  lines), which is around 40% faster to build on typical configs.

  Not much changed from the last version (-v2) posted three weeks ago: I
  eliminated quirks, backmerged fixes plus I rebased it to an upstream
  SHA1 from yesterday that includes most changes queued up in -next plus
  all sched.h changes that were pending from Andrew.

  I've re-tested the series both on x86 and on cross-arch defconfigs,
  and did a bisectability test at a number of random points.

  I tried to test as many build configurations as possible, but some
  build breakage is probably still left - but it should be mostly
  limited to architectures that have no cross-compiler binaries
  available on kernel.org, and non-default configurations"

* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
  sched/headers: Clean up <linux/sched.h>
  sched/headers: Remove #ifdefs from <linux/sched.h>
  sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
  sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
  sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
  sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
  sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
  sched/core: Remove unused prefetch_stack()
  sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
  sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
  sched/headers: Remove <linux/signal.h> from <linux/sched.h>
  sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
  sched/headers: Remove the runqueue_is_locked() prototype
  sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
  sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
  sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
  ...
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-02T23:20:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2017-03-02T23:20:00+00:00 94e877d0fb43bec0540d6a37d49cb4f7f05a5348 Pull vfs pile two from Al Viro: - orangefs fix - series of fs/namei.c cleanups from me - VFS stuff coming from overlayfs tree * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: orangefs: Use RCU for destroy_inode vfs: use helper for calling f_op->fsync() mm: use helper for calling f_op->mmap() vfs: use helpers for calling f_op->{read,write}_iter() vfs: pass type instead of fn to do_{loop,iter}_readv_writev() vfs: extract common parts of {compat_,}do_readv_writev() vfs: wrap write f_ops with file_{start,end}_write() vfs: deny copy_file_range() for non regular files vfs: deny fallocate() on directory vfs: create vfs helper vfs_tmpfile() namei.c: split unlazy_walk() namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate() lookup_fast(): clean up the logics around the fallback to non-rcu mode namei: fold unlazy_link() into its sole caller 
Pull vfs pile two from Al Viro:

 - orangefs fix

 - series of fs/namei.c cleanups from me

 - VFS stuff coming from overlayfs tree

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  orangefs: Use RCU for destroy_inode
  vfs: use helper for calling f_op->fsync()
  mm: use helper for calling f_op->mmap()
  vfs: use helpers for calling f_op->{read,write}_iter()
  vfs: pass type instead of fn to do_{loop,iter}_readv_writev()
  vfs: extract common parts of {compat_,}do_readv_writev()
  vfs: wrap write f_ops with file_{start,end}_write()
  vfs: deny copy_file_range() for non regular files
  vfs: deny fallocate() on directory
  vfs: create vfs helper vfs_tmpfile()
  namei.c: split unlazy_walk()
  namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()
  lookup_fast(): clean up the logics around the fallback to non-rcu mode
  namei: fold unlazy_link() into its sole caller
Merge remote-tracking branch 'ovl/for-viro' into for-linus 2017-03-02T11:41:22+00:00 Al Viro viro@zeniv.linux.org.uk 2017-03-02T11:41:22+00:00 653a7746fa2f5369985f5368ffc162b6510db6c8 Overlayfs-related series from Miklos and Amir 
Overlayfs-related series from Miklos and Amir
sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02T07:42:32+00:00 Ingo Molnar mingo@kernel.org 2017-02-02T18:15:33+00:00 174cd4b1e5fbd0d74c68cf3a74f5bd4923485512 Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
userfaultfd: non-cooperative: add event for memory unmaps 2017-02-25T01:46:55+00:00 Mike Rapoport rppt@linux.vnet.ibm.com 2017-02-24T22:58:22+00:00 897ab3e0c49e24b62e2d54d165c7afec6bbca65b When a non-cooperative userfaultfd monitor copies pages in the background, it may encounter regions that were already unmapped. Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the virtual memory layout. Since there might be different uffd contexts for the affected VMAs, we first should create a temporary representation for the unmap event for each uffd context and then notify them one by one to the appropriate userfault file descriptors. The event notification occurs after the mmap_sem has been released. [arnd@arndb.de: fix nommu build] Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de [mhocko@suse.com: fix nommu build] Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
When a non-cooperative userfaultfd monitor copies pages in the
background, it may encounter regions that were already unmapped.
Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely
changes in the virtual memory layout.

Since there might be different uffd contexts for the affected VMAs, we
first should create a temporary representation for the unmap event for
each uffd context and then notify them one by one to the appropriate
userfault file descriptors.

The event notification occurs after the mmap_sem has been released.

[arnd@arndb.de: fix nommu build]
  Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de
[mhocko@suse.com: fix nommu build]
  Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vfs: use helpers for calling f_op->{read,write}_iter() 2017-02-20T15:51:23+00:00 Miklos Szeredi mszeredi@redhat.com 2017-02-20T15:51:23+00:00 bb7462b6fd64e40809a857223bf7f0e628969f87 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
aio: fix lock dep warning 2017-01-15T00:31:40+00:00 Shaohua Li shli@fb.com 2016-12-13T20:09:56+00:00 a12f1ae61c489076a9aeb90bddca7722bf330df3 lockdep reports a warnning. file_start_write/file_end_write only acquire/release the lock for regular files. So checking the files in aio side too. [ 453.532141] ------------[ cut here ]------------ [ 453.533011] WARNING: CPU: 1 PID: 1298 at ../kernel/locking/lockdep.c:3514 lock_release+0x434/0x670 [ 453.533011] DEBUG_LOCKS_WARN_ON(depth <= 0) [ 453.533011] Modules linked in: [ 453.533011] CPU: 1 PID: 1298 Comm: fio Not tainted 4.9.0+ #964 [ 453.533011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014 [ 453.533011] ffff8803a24b7a70 ffffffff8196cffb ffff8803a24b7ae8 0000000000000000 [ 453.533011] ffff8803a24b7ab8 ffffffff81091ee1 ffff8803a5dba700 00000dba00000008 [ 453.533011] ffffed0074496f59 ffff8803a5dbaf54 ffff8803ae0f8488 fffffffffffffdef [ 453.533011] Call Trace: [ 453.533011] [<ffffffff8196cffb>] dump_stack+0x67/0x9c [ 453.533011] [<ffffffff81091ee1>] __warn+0x111/0x130 [ 453.533011] [<ffffffff81091f97>] warn_slowpath_fmt+0x97/0xb0 [ 453.533011] [<ffffffff81091f00>] ? __warn+0x130/0x130 [ 453.533011] [<ffffffff8191b789>] ? blk_finish_plug+0x29/0x60 [ 453.533011] [<ffffffff811205d4>] lock_release+0x434/0x670 [ 453.533011] [<ffffffff8198af94>] ? import_single_range+0xd4/0x110 [ 453.533011] [<ffffffff81322195>] ? rw_verify_area+0x65/0x140 [ 453.533011] [<ffffffff813aa696>] ? aio_write+0x1f6/0x280 [ 453.533011] [<ffffffff813aa6c9>] aio_write+0x229/0x280 [ 453.533011] [<ffffffff813aa4a0>] ? aio_complete+0x640/0x640 [ 453.533011] [<ffffffff8111df20>] ? debug_check_no_locks_freed+0x1a0/0x1a0 [ 453.533011] [<ffffffff8114793a>] ? debug_lockdep_rcu_enabled.part.2+0x1a/0x30 [ 453.533011] [<ffffffff81147985>] ? debug_lockdep_rcu_enabled+0x35/0x40 [ 453.533011] [<ffffffff812a92be>] ? __might_fault+0x7e/0xf0 [ 453.533011] [<ffffffff813ac9bc>] do_io_submit+0x94c/0xb10 [ 453.533011] [<ffffffff813ac2ae>] ? do_io_submit+0x23e/0xb10 [ 453.533011] [<ffffffff813ac070>] ? SyS_io_destroy+0x270/0x270 [ 453.533011] [<ffffffff8111d7b3>] ? mark_held_locks+0x23/0xc0 [ 453.533011] [<ffffffff8100201a>] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 453.533011] [<ffffffff813acb90>] SyS_io_submit+0x10/0x20 [ 453.533011] [<ffffffff824f96aa>] entry_SYSCALL_64_fastpath+0x18/0xad [ 453.533011] [<ffffffff81119190>] ? trace_hardirqs_off_caller+0xc0/0x110 [ 453.533011] ---[ end trace b2fbe664d1cc0082 ]--- Cc: Dmitry Monakhov <dmonakhov@openvz.org> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
lockdep reports a warnning. file_start_write/file_end_write only
acquire/release the lock for regular files. So checking the files in aio
side too.

[  453.532141] ------------[ cut here ]------------
[  453.533011] WARNING: CPU: 1 PID: 1298 at ../kernel/locking/lockdep.c:3514 lock_release+0x434/0x670
[  453.533011] DEBUG_LOCKS_WARN_ON(depth <= 0)
[  453.533011] Modules linked in:
[  453.533011] CPU: 1 PID: 1298 Comm: fio Not tainted 4.9.0+ #964
[  453.533011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014
[  453.533011]  ffff8803a24b7a70 ffffffff8196cffb ffff8803a24b7ae8 0000000000000000
[  453.533011]  ffff8803a24b7ab8 ffffffff81091ee1 ffff8803a5dba700 00000dba00000008
[  453.533011]  ffffed0074496f59 ffff8803a5dbaf54 ffff8803ae0f8488 fffffffffffffdef
[  453.533011] Call Trace:
[  453.533011]  [<ffffffff8196cffb>] dump_stack+0x67/0x9c
[  453.533011]  [<ffffffff81091ee1>] __warn+0x111/0x130
[  453.533011]  [<ffffffff81091f97>] warn_slowpath_fmt+0x97/0xb0
[  453.533011]  [<ffffffff81091f00>] ? __warn+0x130/0x130
[  453.533011]  [<ffffffff8191b789>] ? blk_finish_plug+0x29/0x60
[  453.533011]  [<ffffffff811205d4>] lock_release+0x434/0x670
[  453.533011]  [<ffffffff8198af94>] ? import_single_range+0xd4/0x110
[  453.533011]  [<ffffffff81322195>] ? rw_verify_area+0x65/0x140
[  453.533011]  [<ffffffff813aa696>] ? aio_write+0x1f6/0x280
[  453.533011]  [<ffffffff813aa6c9>] aio_write+0x229/0x280
[  453.533011]  [<ffffffff813aa4a0>] ? aio_complete+0x640/0x640
[  453.533011]  [<ffffffff8111df20>] ? debug_check_no_locks_freed+0x1a0/0x1a0
[  453.533011]  [<ffffffff8114793a>] ? debug_lockdep_rcu_enabled.part.2+0x1a/0x30
[  453.533011]  [<ffffffff81147985>] ? debug_lockdep_rcu_enabled+0x35/0x40
[  453.533011]  [<ffffffff812a92be>] ? __might_fault+0x7e/0xf0
[  453.533011]  [<ffffffff813ac9bc>] do_io_submit+0x94c/0xb10
[  453.533011]  [<ffffffff813ac2ae>] ? do_io_submit+0x23e/0xb10
[  453.533011]  [<ffffffff813ac070>] ? SyS_io_destroy+0x270/0x270
[  453.533011]  [<ffffffff8111d7b3>] ? mark_held_locks+0x23/0xc0
[  453.533011]  [<ffffffff8100201a>] ? trace_hardirqs_on_thunk+0x1a/0x1c
[  453.533011]  [<ffffffff813acb90>] SyS_io_submit+0x10/0x20
[  453.533011]  [<ffffffff824f96aa>] entry_SYSCALL_64_fastpath+0x18/0xad
[  453.533011]  [<ffffffff81119190>] ? trace_hardirqs_off_caller+0xc0/0x110
[  453.533011] ---[ end trace b2fbe664d1cc0082 ]---

Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>