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Author SHA1 Message Date
Linus Torvalds 5cf9ad0e6b io_uring-5.5-2020-01-26
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Merge tag 'io_uring-5.5-2020-01-26' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Fix for two regressions in this cycle, both reported by the postgresql
  use case.

  One removes the added restriction on who can submit IO, making it
  possible for rings shared across forks to do so. The other fixes an
  issue for the same kind of use case, where one exiting process would
  cancel all IO"

* tag 'io_uring-5.5-2020-01-26' of git://git.kernel.dk/linux-block:
  io_uring: don't cancel all work on process exit
  Revert "io_uring: only allow submit from owning task"
2020-01-26 12:23:04 -08:00
Linus Torvalds b1b298914f Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fix from Al Viro:
 "Fix a use-after-free in do_last() handling of sysctl_protected_...
  checks.

  The use-after-free normally doesn't happen there, but race with
  rename() and it becomes possible"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  do_last(): fetch directory ->i_mode and ->i_uid before it's too late
2020-01-26 10:33:48 -08:00
Jens Axboe ebe1002621 io_uring: don't cancel all work on process exit
If we're sharing the ring across forks, then one process exiting means
that we cancel ALL work and prevent future work. This is overly
restrictive. As long as we cancel the work associated with the files
from the current task, it's safe to let others persist. Normal fd close
on exit will still wait (and cancel) pending work.

Fixes: fcb323cc53 ("io_uring: io_uring: add support for async work inheriting files")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-26 10:17:12 -07:00
Jens Axboe 73e08e711d Revert "io_uring: only allow submit from owning task"
This ends up being too restrictive for tasks that willingly fork and
share the ring between forks. Andres reports that this breaks his
postgresql work. Since we're close to 5.5 release, revert this change
for now.

Cc: stable@vger.kernel.org
Fixes: 44d282796f ("io_uring: only allow submit from owning task")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-26 09:56:05 -07:00
David Howells a45ea48e2b afs: Fix characters allowed into cell names
The afs filesystem needs to prohibit certain characters from cell names,
such as '/', as these are used to form filenames in procfs, leading to
the following warning being generated:

	WARNING: CPU: 0 PID: 3489 at fs/proc/generic.c:178

Fix afs_alloc_cell() to disallow nonprintable characters, '/', '@' and
names that begin with a dot.

Remove the check for "@cell" as that is then redundant.

This can be tested by running:

	echo add foo/.bar 1.2.3.4 >/proc/fs/afs/cells

Note that we will also need to deal with:

 - Names ending in ".invalid" shouldn't be passed to the DNS.

 - Names that contain non-valid domainname chars shouldn't be passed to
   the DNS.

 - DNS replies that say "your-dns-needs-immediate-attention.<gTLD>" and
   replies containing A records that say 127.0.53.53 should be
   considered invalid.
   [https://www.icann.org/en/system/files/files/name-collision-mitigation-01aug14-en.pdf]

but these need to be dealt with by the kafs-client DNS program rather
than the kernel.

Reported-by: syzbot+b904ba7c947a37b4b291@syzkaller.appspotmail.com
Cc: stable@kernel.org
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-26 08:54:04 -08:00
Al Viro d0cb50185a do_last(): fetch directory ->i_mode and ->i_uid before it's too late
may_create_in_sticky() call is done when we already have dropped the
reference to dir.

Fixes: 30aba6656f (namei: allow restricted O_CREAT of FIFOs and regular files)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-01-26 09:31:07 -05:00
Linus Torvalds a075f23dd4 for-5.5-rc8-tag
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Merge tag 'for-5.5-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "Here's a last minute fix for a regression introduced in this
  development cycle.

  There's a small chance of a silent corruption when device replace and
  NOCOW data writes happen at the same time in one block group. Metadata
  or COW data writes are unaffected.

  The extra fixup patch is there to silence an unnecessary warning"

* tag 'for-5.5-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: dev-replace: remove warning for unknown return codes when finished
  btrfs: scrub: Require mandatory block group RO for dev-replace
2020-01-25 10:55:24 -08:00
David Sterba 4cea9037f8 btrfs: dev-replace: remove warning for unknown return codes when finished
The fstests btrfs/011 triggered a warning at the end of device replace,

  [ 1891.998975] BTRFS warning (device vdd): failed setting block group ro: -28
  [ 1892.038338] BTRFS error (device vdd): btrfs_scrub_dev(/dev/vdd, 1, /dev/vdb) failed -28
  [ 1892.059993] ------------[ cut here ]------------
  [ 1892.063032] WARNING: CPU: 2 PID: 2244 at fs/btrfs/dev-replace.c:506 btrfs_dev_replace_start.cold+0xf9/0x140 [btrfs]
  [ 1892.074346] CPU: 2 PID: 2244 Comm: btrfs Not tainted 5.5.0-rc7-default+ #942
  [ 1892.079956] RIP: 0010:btrfs_dev_replace_start.cold+0xf9/0x140 [btrfs]

  [ 1892.096576] RSP: 0018:ffffbb58c7b3fd10 EFLAGS: 00010286
  [ 1892.098311] RAX: 00000000ffffffe4 RBX: 0000000000000001 RCX: 8888888888888889
  [ 1892.100342] RDX: 0000000000000001 RSI: ffff9e889645f5d8 RDI: ffffffff92821080
  [ 1892.102291] RBP: ffff9e889645c000 R08: 000001b8878fe1f6 R09: 0000000000000000
  [ 1892.104239] R10: ffffbb58c7b3fd08 R11: 0000000000000000 R12: ffff9e88a0017000
  [ 1892.106434] R13: ffff9e889645f608 R14: ffff9e88794e1000 R15: ffff9e88a07b5200
  [ 1892.108642] FS:  00007fcaed3f18c0(0000) GS:ffff9e88bda00000(0000) knlGS:0000000000000000
  [ 1892.111558] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 1892.113492] CR2: 00007f52509ff420 CR3: 00000000603dd002 CR4: 0000000000160ee0

  [ 1892.115814] Call Trace:
  [ 1892.116896]  btrfs_dev_replace_by_ioctl+0x35/0x60 [btrfs]
  [ 1892.118962]  btrfs_ioctl+0x1d62/0x2550 [btrfs]

caused by the previous patch ("btrfs: scrub: Require mandatory block
group RO for dev-replace"). Hitting ENOSPC is possible and could happen
when the block group is set read-only, preventing NOCOW writes to the
area that's being accessed by dev-replace.

This has happend with scratch devices of size 12G but not with 5G and
20G, so this is depends on timing and other activity on the filesystem.
The whole replace operation is restartable, the space state should be
examined by the user in any case.

The error code is propagated back to the ioctl caller so the kernel
warning is causing false alerts.

Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-25 12:49:12 +01:00
Qu Wenruo 1bbb97b8ce btrfs: scrub: Require mandatory block group RO for dev-replace
[BUG]
For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071,
looped runs can lead to random failure, where scrub finds csum error.

The possibility is not high, around 1/20 to 1/100, but it's causing data
corruption.

The bug is observable after commit b12de52896 ("btrfs: scrub: Don't
check free space before marking a block group RO")

[CAUSE]
Dev-replace has two source of writes:

- Write duplication
  All writes to source device will also be duplicated to target device.

  Content:	Not yet persisted data/meta

- Scrub copy
  Dev-replace reused scrub code to iterate through existing extents, and
  copy the verified data to target device.

  Content:	Previously persisted data and metadata

The difference in contents makes the following race possible:
	Regular Writer		|	Dev-replace
-----------------------------------------------------------------
  ^                             |
  | Preallocate one data extent |
  | at bytenr X, len 1M		|
  v				|
  ^ Commit transaction		|
  | Now extent [X, X+1M) is in  |
  v commit root			|
 ================== Dev replace starts =========================
  				| ^
				| | Scrub extent [X, X+1M)
				| | Read [X, X+1M)
				| | (The content are mostly garbage
				| |  since it's preallocated)
  ^				| v
  | Write back happens for	|
  | extent [X, X+512K)		|
  | New data writes to both	|
  | source and target dev.	|
  v				|
				| ^
				| | Scrub writes back extent [X, X+1M)
				| | to target device.
				| | This will over write the new data in
				| | [X, X+512K)
				| v

This race can only happen for nocow writes. Thus metadata and data cow
writes are safe, as COW will never overwrite extents of previous
transaction (in commit root).

This behavior can be confirmed by disabling all fallocate related calls
in fsstress (*), then all related tests can pass a 2000 run loop.

*: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \
		   -f collapse=0 -f punch=0 -f resvsp=0"
   I didn't expect resvsp ioctl will fallback to fallocate in VFS...

[FIX]
Make dev-replace to require mandatory block group RO, and wait for current
nocow writes before calling scrub_chunk().

This patch will mostly revert commit 76a8efa171 ("btrfs: Continue replace
when set_block_ro failed") for dev-replace path.

The side effect is, dev-replace can be more strict on avaialble space, but
definitely worth to avoid data corruption.

Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: 76a8efa171 ("btrfs: Continue replace when set_block_ro failed")
Fixes: b12de52896 ("btrfs: scrub: Don't check free space before marking a block group RO")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 14:35:56 +01:00
Linus Torvalds fa0a4e3b54 A fix for a potential use-after-free from Jeff, marked for stable.
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Merge tag 'ceph-for-5.5-rc8' of https://github.com/ceph/ceph-client

Pull ceph fix from Ilya Dryomov:
 "A fix for a potential use-after-free from Jeff, marked for stable"

* tag 'ceph-for-5.5-rc8' of https://github.com/ceph/ceph-client:
  ceph: hold extra reference to r_parent over life of request
2020-01-23 11:21:35 -08:00
Linus Torvalds 3c2659bd1d readdir: make user_access_begin() use the real access range
In commit 9f79b78ef7 ("Convert filldir[64]() from __put_user() to
unsafe_put_user()") I changed filldir to not do individual __put_user()
accesses, but instead use unsafe_put_user() surrounded by the proper
user_access_begin/end() pair.

That make them enormously faster on modern x86, where the STAC/CLAC
games make individual user accesses fairly heavy-weight.

However, the user_access_begin() range was not really the exact right
one, since filldir() has the unfortunate problem that it needs to not
only fill out the new directory entry, it also needs to fix up the
previous one to contain the proper file offset.

It's unfortunate, but the "d_off" field in "struct dirent" is _not_ the
file offset of the directory entry itself - it's the offset of the next
one.  So we end up backfilling the offset in the previous entry as we
walk along.

But since x86 didn't really care about the exact range, and used to be
the only architecture that did anything fancy in user_access_begin() to
begin with, the filldir[64]() changes did something lazy, and even
commented on it:

	/*
	 * Note! This range-checks 'previous' (which may be NULL).
	 * The real range was checked in getdents
	 */
	if (!user_access_begin(dirent, sizeof(*dirent)))
		goto efault;

and it all worked fine.

But now 32-bit ppc is starting to also implement user_access_begin(),
and the fact that we faked the range to only be the (possibly not even
valid) previous directory entry becomes a problem, because ppc32 will
actually be using the range that is passed in for more than just "check
that it's user space".

This is a complete rewrite of Christophe's original patch.

By saving off the record length of the previous entry instead of a
pointer to it in the filldir data structures, we can simplify the range
check and the writing of the previous entry d_off field.  No need for
any conditionals in the user accesses themselves, although we retain the
conditional EINTR checking for the "was this the first directory entry"
signal handling latency logic.

Fixes: 9f79b78ef7 ("Convert filldir[64]() from __put_user() to unsafe_put_user()")
Link: https://lore.kernel.org/lkml/a02d3426f93f7eb04960a4d9140902d278cab0bb.1579697910.git.christophe.leroy@c-s.fr/
Link: https://lore.kernel.org/lkml/408c90c4068b00ea8f1c41cca45b84ec23d4946b.1579783936.git.christophe.leroy@c-s.fr/
Reported-and-tested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-23 10:15:28 -08:00
Linus Torvalds 2c6b7bcd74 readdir: be more conservative with directory entry names
Commit 8a23eb804c ("Make filldir[64]() verify the directory entry
filename is valid") added some minimal validity checks on the directory
entries passed to filldir[64]().  But they really were pretty minimal.

This fleshes out at least the name length check: we used to disallow
zero-length names, but really, negative lengths or oevr-long names
aren't ok either.  Both could happen if there is some filesystem
corruption going on.

Now, most filesystems tend to use just an "unsigned char" or similar for
the length of a directory entry name, so even with a corrupt filesystem
you should never see anything odd like that.  But since we then use the
name length to create the directory entry record length, let's make sure
it actually is half-way sensible.

Note how POSIX states that the size of a path component is limited by
NAME_MAX, but we actually use PATH_MAX for the check here.  That's
because while NAME_MAX is generally the correct maximum name length
(it's 255, for the same old "name length is usually just a byte on
disk"), there's nothing in the VFS layer that really cares.

So the real limitation at a VFS layer is the total pathname length you
can pass as a filename: PATH_MAX.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-23 10:05:05 -08:00
Linus Torvalds dbab40bdb4 io_uring-5.5-2020-01-22
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Merge tag 'io_uring-5.5-2020-01-22' of git://git.kernel.dk/linux-block

Pull io_uring fix from Jens Axboe:
 "This was supposed to have gone in last week, but due to a brain fart
  on my part, I forgot that we made this struct addition in the 5.5
  cycle. So here it is for 5.5, to prevent having a 32 vs 64-bit
  compatability issue with the files_update command"

* tag 'io_uring-5.5-2020-01-22' of git://git.kernel.dk/linux-block:
  io_uring: fix compat for IORING_REGISTER_FILES_UPDATE
2020-01-22 08:30:09 -08:00
Jeff Layton 9c1c2b35f1 ceph: hold extra reference to r_parent over life of request
Currently, we just assume that it will stick around by virtue of the
submitter's reference, but later patches will allow the syscall to
return early and we can't rely on that reference at that point.

While I'm not aware of any reports of it, Xiubo pointed out that this
may fix a use-after-free.  If the wait for a reply times out or is
canceled via signal, and then the reply comes in after the syscall
returns, the client can end up trying to access r_parent without a
reference.

Take an extra reference to the inode when setting r_parent and release
it when releasing the request.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2020-01-21 19:02:37 +01:00
Eugene Syromiatnikov 1292e972ff io_uring: fix compat for IORING_REGISTER_FILES_UPDATE
fds field of struct io_uring_files_update is problematic with regards
to compat user space, as pointer size is different in 32-bit, 32-on-64-bit,
and 64-bit user space.  In order to avoid custom handling of compat in
the syscall implementation, make fds __u64 and use u64_to_user_ptr in
order to retrieve it.  Also, align the field naturally and check that
no garbage is passed there.

Fixes: c3a31e6056 ("io_uring: add support for IORING_REGISTER_FILES_UPDATE")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:00:44 -07:00
Linus Torvalds d96d875ef5 \n
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Merge tag 'fixes_for_v5.5-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull reiserfs fix from Jan Kara:
 "A fixup of a recently merged reiserfs fix which has caused problem
  when xattrs were not compiled in"

* tag 'fixes_for_v5.5-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  reiserfs: fix handling of -EOPNOTSUPP in reiserfs_for_each_xattr
2020-01-20 11:24:13 -08:00
Linus Torvalds 25e73aadf2 io_uring-5.5-2020-01-16
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Merge tag 'io_uring-5.5-2020-01-16' of git://git.kernel.dk/linux-block

Pull io_uring fixes form Jens Axboe:

 - Ensure ->result is always set when IO is retried (Bijan)

 - In conjunction with the above, fix a regression in polled IO issue
   when retried (me/Bijan)

 - Don't setup async context for read/write fixed, otherwise we may
   wrongly map the iovec on retry (me)

 - Cancel io-wq work if we fail getting mm reference (me)

 - Ensure dependent work is always initialized correctly (me)

 - Only allow original task to submit IO, don't allow it from a passed
   ring fd (me)

* tag 'io_uring-5.5-2020-01-16' of git://git.kernel.dk/linux-block:
  io_uring: only allow submit from owning task
  io_uring: ensure workqueue offload grabs ring mutex for poll list
  io_uring: clear req->result always before issuing a read/write request
  io_uring: be consistent in assigning next work from handler
  io-wq: cancel work if we fail getting a mm reference
  io_uring: don't setup async context for read/write fixed
2020-01-17 11:25:45 -08:00
Linus Torvalds effaf90137 for-5.5-rc6-tag
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Merge tag 'for-5.5-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more fixes that have been in the works during last twp weeks.
  All have a user visible effect and are stable material:

   - scrub: properly update progress after calling cancel ioctl, calling
     'resume' would start from the beginning otherwise

   - fix subvolume reference removal, after moving out of the original
     path the reference is not recognized and will lead to transaction
     abort

   - fix reloc root lifetime checks, could lead to crashes when there's
     subvolume cleaning running in parallel

   - fix memory leak when quotas get disabled in the middle of extent
     accounting

   - fix transaction abort in case of balance being started on degraded
     mount on eg. RAID1"

* tag 'for-5.5-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: check rw_devices, not num_devices for balance
  Btrfs: always copy scrub arguments back to user space
  btrfs: relocation: fix reloc_root lifespan and access
  btrfs: fix memory leak in qgroup accounting
  btrfs: do not delete mismatched root refs
  btrfs: fix invalid removal of root ref
  btrfs: rework arguments of btrfs_unlink_subvol
2020-01-17 11:21:05 -08:00
Linus Torvalds ab7541c3ad fuse fixes for 5.5-rc7
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Merge tag 'fuse-fixes-5.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse fix from Miklos Szeredi:
 "Fix a regression in the last release affecting the ftp module of the
  gvfs filesystem"

* tag 'fuse-fixes-5.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix fuse_send_readpages() in the syncronous read case
2020-01-17 08:42:02 -08:00
Josef Bacik b35cf1f0bf btrfs: check rw_devices, not num_devices for balance
The fstest btrfs/154 reports

  [ 8675.381709] BTRFS: Transaction aborted (error -28)
  [ 8675.383302] WARNING: CPU: 1 PID: 31900 at fs/btrfs/block-group.c:2038 btrfs_create_pending_block_groups+0x1e0/0x1f0 [btrfs]
  [ 8675.390925] CPU: 1 PID: 31900 Comm: btrfs Not tainted 5.5.0-rc6-default+ #935
  [ 8675.392780] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
  [ 8675.395452] RIP: 0010:btrfs_create_pending_block_groups+0x1e0/0x1f0 [btrfs]
  [ 8675.402672] RSP: 0018:ffffb2090888fb00 EFLAGS: 00010286
  [ 8675.404413] RAX: 0000000000000000 RBX: ffff92026dfa91c8 RCX: 0000000000000001
  [ 8675.406609] RDX: 0000000000000000 RSI: ffffffff8e100899 RDI: ffffffff8e100971
  [ 8675.408775] RBP: ffff920247c61660 R08: 0000000000000000 R09: 0000000000000000
  [ 8675.410978] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffe4
  [ 8675.412647] R13: ffff92026db74000 R14: ffff920247c616b8 R15: ffff92026dfbc000
  [ 8675.413994] FS:  00007fd5e57248c0(0000) GS:ffff92027d800000(0000) knlGS:0000000000000000
  [ 8675.416146] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 8675.417833] CR2: 0000564aa51682d8 CR3: 000000006dcbc004 CR4: 0000000000160ee0
  [ 8675.419801] Call Trace:
  [ 8675.420742]  btrfs_start_dirty_block_groups+0x355/0x480 [btrfs]
  [ 8675.422600]  btrfs_commit_transaction+0xc8/0xaf0 [btrfs]
  [ 8675.424335]  reset_balance_state+0x14a/0x190 [btrfs]
  [ 8675.425824]  btrfs_balance.cold+0xe7/0x154 [btrfs]
  [ 8675.427313]  ? kmem_cache_alloc_trace+0x235/0x2c0
  [ 8675.428663]  btrfs_ioctl_balance+0x298/0x350 [btrfs]
  [ 8675.430285]  btrfs_ioctl+0x466/0x2550 [btrfs]
  [ 8675.431788]  ? mem_cgroup_charge_statistics+0x51/0xf0
  [ 8675.433487]  ? mem_cgroup_commit_charge+0x56/0x400
  [ 8675.435122]  ? do_raw_spin_unlock+0x4b/0xc0
  [ 8675.436618]  ? _raw_spin_unlock+0x1f/0x30
  [ 8675.438093]  ? __handle_mm_fault+0x499/0x740
  [ 8675.439619]  ? do_vfs_ioctl+0x56e/0x770
  [ 8675.441034]  do_vfs_ioctl+0x56e/0x770
  [ 8675.442411]  ksys_ioctl+0x3a/0x70
  [ 8675.443718]  ? trace_hardirqs_off_thunk+0x1a/0x1c
  [ 8675.445333]  __x64_sys_ioctl+0x16/0x20
  [ 8675.446705]  do_syscall_64+0x50/0x210
  [ 8675.448059]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  [ 8675.479187] BTRFS: error (device vdb) in btrfs_create_pending_block_groups:2038: errno=-28 No space left

We now use btrfs_can_overcommit() to see if we can flip a block group
read only.  Before this would fail because we weren't taking into
account the usable un-allocated space for allocating chunks.  With my
patches we were allowed to do the balance, which is technically correct.

The test is trying to start balance on degraded mount.  So now we're
trying to allocate a chunk and cannot because we want to allocate a
RAID1 chunk, but there's only 1 device that's available for usage.  This
results in an ENOSPC.

But we shouldn't even be making it this far, we don't have enough
devices to restripe.  The problem is we're using btrfs_num_devices(),
that also includes missing devices. That's not actually what we want, we
need to use rw_devices.

The chunk_mutex is not needed here, rw_devices changes only in device
add, remove or replace, all are excluded by EXCL_OP mechanism.

Fixes: e4d8ec0f65 ("Btrfs: implement online profile changing")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add stacktrace, update changelog, drop chunk_mutex ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 15:40:54 +01:00
Filipe Manana 5afe6ce748 Btrfs: always copy scrub arguments back to user space
If scrub returns an error we are not copying back the scrub arguments
structure to user space. This prevents user space to know how much
progress scrub has done if an error happened - this includes -ECANCELED
which is returned when users ask for scrub to stop. A particular use
case, which is used in btrfs-progs, is to resume scrub after it is
canceled, in that case it relies on checking the progress from the scrub
arguments structure and then use that progress in a call to resume
scrub.

So fix this by always copying the scrub arguments structure to user
space, overwriting the value returned to user space with -EFAULT only if
copying the structure failed to let user space know that either that
copying did not happen, and therefore the structure is stale, or it
happened partially and the structure is probably not valid and corrupt
due to the partial copy.

Reported-by: Graham Cobb <g.btrfs@cobb.uk.net>
Link: https://lore.kernel.org/linux-btrfs/d0a97688-78be-08de-ca7d-bcb4c7fb397e@cobb.uk.net/
Fixes: 06fe39ab15 ("Btrfs: do not overwrite scrub error with fault error in scrub ioctl")
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Tested-by: Graham Cobb <g.btrfs@cobb.uk.net>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-17 15:28:52 +01:00
Jens Axboe 44d282796f io_uring: only allow submit from owning task
If the credentials or the mm doesn't match, don't allow the task to
submit anything on behalf of this ring. The task that owns the ring can
pass the file descriptor to another task, but we don't want to allow
that task to submit an SQE that then assumes the ring mm and creds if
it needs to go async.

Cc: stable@vger.kernel.org
Suggested-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-16 21:43:24 -07:00
Jeff Mahoney 394440d469 reiserfs: fix handling of -EOPNOTSUPP in reiserfs_for_each_xattr
Commit 60e4cf67a5 (reiserfs: fix extended attributes on the root
directory) introduced a regression open_xa_root started returning
-EOPNOTSUPP but it was not handled properly in reiserfs_for_each_xattr.

When the reiserfs module is built without CONFIG_REISERFS_FS_XATTR,
deleting an inode would result in a warning and chowning an inode
would also result in a warning and then fail to complete.

With CONFIG_REISERFS_FS_XATTR enabled, the xattr root would always be
present for read-write operations.

This commit handles -EOPNOSUPP in the same way -ENODATA is handled.

Fixes: 60e4cf67a5 ("reiserfs: fix extended attributes on the root directory")
CC: stable@vger.kernel.org	# Commit 60e4cf67a5 was picked up by stable
Link: https://lore.kernel.org/r/20200115180059.6935-1-jeffm@suse.com
Reported-by: Michael Brunnbauer <brunni@netestate.de>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-01-16 16:49:29 +01:00
Miklos Szeredi 7df1e988c7 fuse: fix fuse_send_readpages() in the syncronous read case
Buffered read in fuse normally goes via:

 -> generic_file_buffered_read()
   -> fuse_readpages()
     -> fuse_send_readpages()
       ->fuse_simple_request() [called since v5.4]

In the case of a read request, fuse_simple_request() will return a
non-negative bytecount on success or a negative error value.  A positive
bytecount was taken to be an error and the PG_error flag set on the page.
This resulted in generic_file_buffered_read() falling back to ->readpage(),
which would repeat the read request and succeed.  Because of the repeated
read succeeding the bug was not detected with regression tests or other use
cases.

The FTP module in GVFS however fails the second read due to the
non-seekable nature of FTP downloads.

Fix by checking and ignoring positive return value from
fuse_simple_request().

Reported-by: Ondrej Holy <oholy@redhat.com>
Link: https://gitlab.gnome.org/GNOME/gvfs/issues/441
Fixes: 134831e36b ("fuse: convert readpages to simple api")
Cc: <stable@vger.kernel.org> # v5.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-16 11:09:36 +01:00
Jens Axboe 11ba820bf1 io_uring: ensure workqueue offload grabs ring mutex for poll list
A previous commit moved the locking for the async sqthread, but didn't
take into account that the io-wq workers still need it. We can't use
req->in_async for this anymore as both the sqthread and io-wq workers
set it, gate the need for locking on io_wq_current_is_worker() instead.

Fixes: 8a4955ff1c ("io_uring: sqthread should grab ctx->uring_lock for submissions")
Reported-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-15 21:51:17 -07:00
Bijan Mottahedeh 797f3f535d io_uring: clear req->result always before issuing a read/write request
req->result is cleared when io_issue_sqe() calls io_read/write_pre()
routines.  Those routines however are not called when the sqe
argument is NULL, which is the case when io_issue_sqe() is called from
io_wq_submit_work().  io_issue_sqe() may then examine a stale result if
a polled request had previously failed with -EAGAIN:

        if (ctx->flags & IORING_SETUP_IOPOLL) {
                if (req->result == -EAGAIN)
                        return -EAGAIN;

                io_iopoll_req_issued(req);
        }

and in turn cause a subsequently completed request to be re-issued in
io_wq_submit_work().

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-15 21:36:13 -07:00
Linus Torvalds 84bf39461e Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "Fixes for mountpoint_last() bugs (by converting to use of
  lookup_last()) and an autofs regression fix from this cycle (caused by
  follow_managed() breakage introduced in barrier fixes series)"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix autofs regression caused by follow_managed() changes
  reimplement path_mountpoint() with less magic
2020-01-15 09:58:14 -08:00
Al Viro 508c877276 fix autofs regression caused by follow_managed() changes
we need to reload ->d_flags after the call of ->d_manage() - the thing
might've been called with dentry still negative and have the damn thing
turned positive while we'd waited.

Fixes: d41efb522e "fs/namei.c: pull positivity check into follow_managed()"
Reported-by: Ian Kent <raven@themaw.net>
Tested-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-01-15 01:36:46 -05:00
Al Viro c64cd6e34e reimplement path_mountpoint() with less magic
... and get rid of a bunch of bugs in it.  Background:
the reason for path_mountpoint() is that umount() really doesn't
want attempts to revalidate the root of what it's trying to umount.
The thing we want to avoid actually happen from complete_walk();
solution was to do something parallel to normal path_lookupat()
and it both went overboard and got the boilerplate subtly
(and not so subtly) wrong.

A better solution is to do pretty much what the normal path_lookupat()
does, but instead of complete_walk() do unlazy_walk().  All it takes
to avoid that ->d_weak_revalidate() call...  mountpoint_last() goes
away, along with everything it got wrong, and so does the magic around
LOOKUP_NO_REVAL.

Another source of bugs is that when we traverse mounts at the final
location (and we need to do that - umount . expects to get whatever's
overmounting ., if any, out of the lookup) we really ought to take
care of ->d_manage() - as it is, manual umount of autofs automount
in progress can lead to unpleasant surprises for the daemon.  Easily
solved by using handle_lookup_down() instead of follow_mount().

Tested-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-01-15 01:36:06 -05:00
Jens Axboe 78912934f4 io_uring: be consistent in assigning next work from handler
If we pass back dependent work in case of links, we need to always
ensure that we call the link setup and work prep handler. If not, we
might be missing some setup for the next work item.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-14 22:09:06 -07:00
Jens Axboe e0bbb3461a io-wq: cancel work if we fail getting a mm reference
If we require mm and user context, mark the request for cancellation
if we fail to acquire the desired mm.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-14 22:06:11 -07:00
Linus Torvalds e033e7d4a8 Merge branch 'dhowells' (patches from DavidH)
Merge misc fixes from David Howells.

Two afs fixes and a key refcounting fix.

* dhowells:
  afs: Fix afs_lookup() to not clobber the version on a new dentry
  afs: Fix use-after-loss-of-ref
  keys: Fix request_key() cache
2020-01-14 09:56:31 -08:00
David Howells f52b83b0b1 afs: Fix afs_lookup() to not clobber the version on a new dentry
Fix afs_lookup() to not clobber the version set on a new dentry by
afs_do_lookup() - especially as it's using the wrong version of the
version (we need to use the one given to us by whatever op the dir
contents correspond to rather than what's in the afs_vnode).

Fixes: 9dd0b82ef5 ("afs: Fix missing dentry data version updating")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-14 09:40:06 -08:00
David Howells 40a708bd62 afs: Fix use-after-loss-of-ref
afs_lookup() has a tracepoint to indicate the outcome of
d_splice_alias(), passing it the inode to retrieve the fid from.
However, the function gave up its ref on that inode when it called
d_splice_alias(), which may have failed and dropped the inode.

Fix this by caching the fid.

Fixes: 80548b0399 ("afs: Add more tracepoints")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-14 09:40:06 -08:00
Jens Axboe 74566df3a7 io_uring: don't setup async context for read/write fixed
We don't need it, and if we have it, then the retry handler will attempt
to copy the non-existent iovec with the inline iovec, with a segment
count that doesn't make sense.

Fixes: f67676d160 ("io_uring: ensure async punted read/write requests copy iovec")
Reported-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-13 19:25:29 -07:00
Qu Wenruo 6282675e67 btrfs: relocation: fix reloc_root lifespan and access
[BUG]
There are several different KASAN reports for balance + snapshot
workloads.  Involved call paths include:

   should_ignore_root+0x54/0xb0 [btrfs]
   build_backref_tree+0x11af/0x2280 [btrfs]
   relocate_tree_blocks+0x391/0xb80 [btrfs]
   relocate_block_group+0x3e5/0xa00 [btrfs]
   btrfs_relocate_block_group+0x240/0x4d0 [btrfs]
   btrfs_relocate_chunk+0x53/0xf0 [btrfs]
   btrfs_balance+0xc91/0x1840 [btrfs]
   btrfs_ioctl_balance+0x416/0x4e0 [btrfs]
   btrfs_ioctl+0x8af/0x3e60 [btrfs]
   do_vfs_ioctl+0x831/0xb10

   create_reloc_root+0x9f/0x460 [btrfs]
   btrfs_reloc_post_snapshot+0xff/0x6c0 [btrfs]
   create_pending_snapshot+0xa9b/0x15f0 [btrfs]
   create_pending_snapshots+0x111/0x140 [btrfs]
   btrfs_commit_transaction+0x7a6/0x1360 [btrfs]
   btrfs_mksubvol+0x915/0x960 [btrfs]
   btrfs_ioctl_snap_create_transid+0x1d5/0x1e0 [btrfs]
   btrfs_ioctl_snap_create_v2+0x1d3/0x270 [btrfs]
   btrfs_ioctl+0x241b/0x3e60 [btrfs]
   do_vfs_ioctl+0x831/0xb10

   btrfs_reloc_pre_snapshot+0x85/0xc0 [btrfs]
   create_pending_snapshot+0x209/0x15f0 [btrfs]
   create_pending_snapshots+0x111/0x140 [btrfs]
   btrfs_commit_transaction+0x7a6/0x1360 [btrfs]
   btrfs_mksubvol+0x915/0x960 [btrfs]
   btrfs_ioctl_snap_create_transid+0x1d5/0x1e0 [btrfs]
   btrfs_ioctl_snap_create_v2+0x1d3/0x270 [btrfs]
   btrfs_ioctl+0x241b/0x3e60 [btrfs]
   do_vfs_ioctl+0x831/0xb10

[CAUSE]
All these call sites are only relying on root->reloc_root, which can
undergo btrfs_drop_snapshot(), and since we don't have real refcount
based protection to reloc roots, we can reach already dropped reloc
root, triggering KASAN.

[FIX]
To avoid such access to unstable root->reloc_root, we should check
BTRFS_ROOT_DEAD_RELOC_TREE bit first.

This patch introduces wrappers that provide the correct way to check the
bit with memory barriers protection.

Most callers don't distinguish merged reloc tree and no reloc tree.  The
only exception is should_ignore_root(), as merged reloc tree can be
ignored, while no reloc tree shouldn't.

[CRITICAL SECTION ANALYSIS]
Although test_bit()/set_bit()/clear_bit() doesn't imply a barrier, the
DEAD_RELOC_TREE bit has extra help from transaction as a higher level
barrier, the lifespan of root::reloc_root and DEAD_RELOC_TREE bit are:

	NULL: reloc_root is NULL	PTR: reloc_root is not NULL
	0: DEAD_RELOC_ROOT bit not set	DEAD: DEAD_RELOC_ROOT bit set

	(NULL, 0)    Initial state		 __
	  |					 /\ Section A
        btrfs_init_reloc_root()			 \/
	  |				 	 __
	(PTR, 0)     reloc_root initialized      /\
          |					 |
	btrfs_update_reloc_root()		 |  Section B
          |					 |
	(PTR, DEAD)  reloc_root has been merged  \/
          |					 __
	=== btrfs_commit_transaction() ====================
	  |					 /\
	clean_dirty_subvols()			 |
	  |					 |  Section C
	(NULL, DEAD) reloc_root cleanup starts   \/
          |					 __
	btrfs_drop_snapshot()			 /\
	  |					 |  Section D
	(NULL, 0)    Back to initial state	 \/

Every have_reloc_root() or test_bit(DEAD_RELOC_ROOT) caller holds
transaction handle, so none of such caller can cross transaction boundary.

In Section A, every caller just found no DEAD bit, and grab reloc_root.

In the cross section A-B, caller may get no DEAD bit, but since reloc_root
is still completely valid thus accessing reloc_root is completely safe.

No test_bit() caller can cross the boundary of Section B and Section C.

In Section C, every caller found the DEAD bit, so no one will access
reloc_root.

In the cross section C-D, either caller gets the DEAD bit set, avoiding
access reloc_root no matter if it's safe or not.  Or caller get the DEAD
bit cleared, then access reloc_root, which is already NULL, nothing will
be wrong.

The memory write barriers are between the reloc_root updates and bit
set/clear, the pairing read side is before test_bit.

Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ barriers ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-13 23:10:56 +01:00
Linus Torvalds 9fb7007de8 Char/Misc patch for 5.5-rc6
Here is a single fix, for the chrdev core, for 5.5-rc6
 
 There's been a long-standing race condition triggered by syzbot, and
 occasionally real people, in the chrdev open() path.  Will finally took
 the time to track it down and fix it for real before the holidays.
 
 Here's that one patch, it's been in linux-next for a while with no
 reported issues and it does fix the reported problem.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc fix from Greg KH:
 "Here is a single fix, for the chrdev core, for 5.5-rc6

  There's been a long-standing race condition triggered by syzbot, and
  occasionally real people, in the chrdev open() path. Will finally took
  the time to track it down and fix it for real before the holidays.

  Here's that one patch, it's been in linux-next for a while with no
  reported issues and it does fix the reported problem"

* tag 'char-misc-5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  chardev: Avoid potential use-after-free in 'chrdev_open()'
2020-01-10 13:25:24 -08:00
Linus Torvalds 4e4cd21c64 block-5.5-2020-01-10
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Merge tag 'block-5.5-2020-01-10' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A few fixes that should go into this round.

  This pull request contains two NVMe fixes via Keith, removal of a dead
  function, and a fix for the bio op for read truncates (Ming)"

* tag 'block-5.5-2020-01-10' of git://git.kernel.dk/linux-block:
  nvmet: fix per feat data len for get_feature
  nvme: Translate more status codes to blk_status_t
  fs: move guard_bio_eod() after bio_set_op_attrs
  block: remove unused mp_bvec_last_segment
2020-01-10 12:05:26 -08:00
Linus Torvalds 30b6487d15 io_uring-5.5-2020-01-10
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Merge tag 'io_uring-5.5-2020-01-10' of git://git.kernel.dk/linux-block

Pull io_uring fix from Jens Axboe:
 "Single fix for this series, fixing a regression with the short read
  handling.

  This just removes it, as it cannot safely be done for all cases"

* tag 'io_uring-5.5-2020-01-10' of git://git.kernel.dk/linux-block:
  io_uring: remove punt of short reads to async context
2020-01-10 12:03:12 -08:00
Linus Torvalds bef1d88263 pstore fix for rare error path
- Fix label allocation lifetime/visibility to avoid further mistakes
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Merge tag 'pstore-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore fix from Kees Cook:
 "Cengiz Can forwarded a Coverity report about more problems with a rare
  pstore initialization error path, so the allocation lifetime was
  rearranged to avoid needing to share the kfree() responsibilities
  between caller and callee"

* tag 'pstore-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Regularize prz label allocation lifetime
2020-01-09 21:42:05 -08:00
Ming Lei 83c9c54716 fs: move guard_bio_eod() after bio_set_op_attrs
Commit 85a8ce62c2 ("block: add bio_truncate to fix guard_bio_eod")
adds bio_truncate() for handling bio EOD. However, bio_truncate()
doesn't use the passed 'op' parameter from guard_bio_eod's callers.

So bio_trunacate() may retrieve wrong 'op', and zering pages may
not be done for READ bio.

Fixes this issue by moving guard_bio_eod() after bio_set_op_attrs()
in submit_bh_wbc() so that bio_truncate() can always retrieve correct
op info.

Meantime remove the 'op' parameter from guard_bio_eod() because it isn't
used any more.

Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Fixes: 85a8ce62c2 ("block: add bio_truncate to fix guard_bio_eod")
Signed-off-by: Ming Lei <ming.lei@redhat.com>

Fold in kerneldoc and bio_op() change.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-09 08:16:12 -07:00
Kees Cook e163fdb3f7 pstore/ram: Regularize prz label allocation lifetime
In my attempt to fix a memory leak, I introduced a double-free in the
pstore error path. Instead of trying to manage the allocation lifetime
between persistent_ram_new() and its callers, adjust the logic so
persistent_ram_new() always takes a kstrdup() copy, and leaves the
caller's allocation lifetime up to the caller. Therefore callers are
_always_ responsible for freeing their label. Before, it only needed
freeing when the prz itself failed to allocate, and not in any of the
other prz failure cases, which callers would have no visibility into,
which is the root design problem that lead to both the leak and now
double-free bugs.

Reported-by: Cengiz Can <cengiz@kernel.wtf>
Link: https://lore.kernel.org/lkml/d4ec59002ede4aaf9928c7f7526da87c@kernel.wtf
Fixes: 8df955a32a ("pstore/ram: Fix error-path memory leak in persistent_ram_new() callers")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-01-08 17:05:45 -08:00
Johannes Thumshirn 26ef8493e1 btrfs: fix memory leak in qgroup accounting
When running xfstests on the current btrfs I get the following splat from
kmemleak:

unreferenced object 0xffff88821b2404e0 (size 32):
  comm "kworker/u4:7", pid 26663, jiffies 4295283698 (age 8.776s)
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 10 ff fd 26 82 88 ff ff  ...........&....
    10 ff fd 26 82 88 ff ff 20 ff fd 26 82 88 ff ff  ...&.... ..&....
  backtrace:
    [<00000000f94fd43f>] ulist_alloc+0x25/0x60 [btrfs]
    [<00000000fd023d99>] btrfs_find_all_roots_safe+0x41/0x100 [btrfs]
    [<000000008f17bd32>] btrfs_find_all_roots+0x52/0x70 [btrfs]
    [<00000000b7660afb>] btrfs_qgroup_rescan_worker+0x343/0x680 [btrfs]
    [<0000000058e66778>] btrfs_work_helper+0xac/0x1e0 [btrfs]
    [<00000000f0188930>] process_one_work+0x1cf/0x350
    [<00000000af5f2f8e>] worker_thread+0x28/0x3c0
    [<00000000b55a1add>] kthread+0x109/0x120
    [<00000000f88cbd17>] ret_from_fork+0x35/0x40

This corresponds to:

  (gdb) l *(btrfs_find_all_roots_safe+0x41)
  0x8d7e1 is in btrfs_find_all_roots_safe (fs/btrfs/backref.c:1413).
  1408
  1409            tmp = ulist_alloc(GFP_NOFS);
  1410            if (!tmp)
  1411                    return -ENOMEM;
  1412            *roots = ulist_alloc(GFP_NOFS);
  1413            if (!*roots) {
  1414                    ulist_free(tmp);
  1415                    return -ENOMEM;
  1416            }
  1417

Following the lifetime of the allocated 'roots' ulist, it gets freed
again in btrfs_qgroup_account_extent().

But this does not happen if the function is called with the
'BTRFS_FS_QUOTA_ENABLED' flag cleared, then btrfs_qgroup_account_extent()
does a short leave and directly returns.

Instead of directly returning we should jump to the 'out_free' in order to
free all resources as expected.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08 17:56:17 +01:00
Josef Bacik 423a716cd7 btrfs: do not delete mismatched root refs
btrfs_del_root_ref() will simply WARN_ON() if the ref doesn't match in
any way, and then continue to delete the reference.  This shouldn't
happen, we have these values because there's more to the reference than
the original root and the sub root.  If any of these checks fail, return
-ENOENT.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08 14:44:24 +01:00
Josef Bacik d49d3287e7 btrfs: fix invalid removal of root ref
If we have the following sequence of events

  btrfs sub create A
  btrfs sub create A/B
  btrfs sub snap A C
  mkdir C/foo
  mv A/B C/foo
  rm -rf *

We will end up with a transaction abort.

The reason for this is because we create a root ref for B pointing to A.
When we create a snapshot of C we still have B in our tree, but because
the root ref points to A and not C we will make it appear to be empty.

The problem happens when we move B into C.  This removes the root ref
for B pointing to A and adds a ref of B pointing to C.  When we rmdir C
we'll see that we have a ref to our root and remove the root ref,
despite not actually matching our reference name.

Now btrfs_del_root_ref() allowing this to work is a bug as well, however
we know that this inode does not actually point to a root ref in the
first place, so we shouldn't be calling btrfs_del_root_ref() in the
first place and instead simply look up our dir index for this item and
do the rest of the removal.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08 14:44:23 +01:00
Josef Bacik 045d3967b6 btrfs: rework arguments of btrfs_unlink_subvol
btrfs_unlink_subvol takes the name of the dentry and the root objectid
based on what kind of inode this is, either a real subvolume link or a
empty one that we inherited as a snapshot.  We need to fix how we unlink
in the case for BTRFS_EMPTY_SUBVOL_DIR_OBJECTID in the future, so rework
btrfs_unlink_subvol to just take the dentry and handle getting the right
objectid given the type of inode this is.  There is no functional change
here, simply pushing the work into btrfs_unlink_subvol() proper.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08 14:43:34 +01:00
Jens Axboe eacc6dfaea io_uring: remove punt of short reads to async context
We currently punt any short read on a regular file to async context,
but this fails if the short read is due to running into EOF. This is
especially problematic since we only do the single prep for commands
now, as we don't reset kiocb->ki_pos. This can result in a 4k read on
a 1k file returning zero, as we detect the short read and then retry
from async context. At the time of retry, the position is now 1k, and
we end up reading nothing, and hence return 0.

Instead of trying to patch around the fact that short reads can be
legitimate and won't succeed in case of retry, remove the logic to punt
a short read to async context. Simply return it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-07 13:08:56 -07:00
Will Deacon 68faa679b8 chardev: Avoid potential use-after-free in 'chrdev_open()'
'chrdev_open()' calls 'cdev_get()' to obtain a reference to the
'struct cdev *' stashed in the 'i_cdev' field of the target inode
structure. If the pointer is NULL, then it is initialised lazily by
looking up the kobject in the 'cdev_map' and so the whole procedure is
protected by the 'cdev_lock' spinlock to serialise initialisation of
the shared pointer.

Unfortunately, it is possible for the initialising thread to fail *after*
installing the new pointer, for example if the subsequent '->open()' call
on the file fails. In this case, 'cdev_put()' is called, the reference
count on the kobject is dropped and, if nobody else has taken a reference,
the release function is called which finally clears 'inode->i_cdev' from
'cdev_purge()' before potentially freeing the object. The problem here
is that a racing thread can happily take the 'cdev_lock' and see the
non-NULL pointer in the inode, which can result in a refcount increment
from zero and a warning:

  |  ------------[ cut here ]------------
  |  refcount_t: addition on 0; use-after-free.
  |  WARNING: CPU: 2 PID: 6385 at lib/refcount.c:25 refcount_warn_saturate+0x6d/0xf0
  |  Modules linked in:
  |  CPU: 2 PID: 6385 Comm: repro Not tainted 5.5.0-rc2+ #22
  |  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
  |  RIP: 0010:refcount_warn_saturate+0x6d/0xf0
  |  Code: 05 55 9a 15 01 01 e8 9d aa c8 ff 0f 0b c3 80 3d 45 9a 15 01 00 75 ce 48 c7 c7 00 9c 62 b3 c6 08
  |  RSP: 0018:ffffb524c1b9bc70 EFLAGS: 00010282
  |  RAX: 0000000000000000 RBX: ffff9e9da1f71390 RCX: 0000000000000000
  |  RDX: ffff9e9dbbd27618 RSI: ffff9e9dbbd18798 RDI: ffff9e9dbbd18798
  |  RBP: 0000000000000000 R08: 000000000000095f R09: 0000000000000039
  |  R10: 0000000000000000 R11: ffffb524c1b9bb20 R12: ffff9e9da1e8c700
  |  R13: ffffffffb25ee8b0 R14: 0000000000000000 R15: ffff9e9da1e8c700
  |  FS:  00007f3b87d26700(0000) GS:ffff9e9dbbd00000(0000) knlGS:0000000000000000
  |  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  |  CR2: 00007fc16909c000 CR3: 000000012df9c000 CR4: 00000000000006e0
  |  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  |  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  |  Call Trace:
  |   kobject_get+0x5c/0x60
  |   cdev_get+0x2b/0x60
  |   chrdev_open+0x55/0x220
  |   ? cdev_put.part.3+0x20/0x20
  |   do_dentry_open+0x13a/0x390
  |   path_openat+0x2c8/0x1470
  |   do_filp_open+0x93/0x100
  |   ? selinux_file_ioctl+0x17f/0x220
  |   do_sys_open+0x186/0x220
  |   do_syscall_64+0x48/0x150
  |   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  |  RIP: 0033:0x7f3b87efcd0e
  |  Code: 89 54 24 08 e8 a3 f4 ff ff 8b 74 24 0c 48 8b 3c 24 41 89 c0 44 8b 54 24 08 b8 01 01 00 00 89 f4
  |  RSP: 002b:00007f3b87d259f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
  |  RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3b87efcd0e
  |  RDX: 0000000000000000 RSI: 00007f3b87d25a80 RDI: 00000000ffffff9c
  |  RBP: 00007f3b87d25e90 R08: 0000000000000000 R09: 0000000000000000
  |  R10: 0000000000000000 R11: 0000000000000293 R12: 00007ffe188f504e
  |  R13: 00007ffe188f504f R14: 00007f3b87d26700 R15: 0000000000000000
  |  ---[ end trace 24f53ca58db8180a ]---

Since 'cdev_get()' can already fail to obtain a reference, simply move
it over to use 'kobject_get_unless_zero()' instead of 'kobject_get()',
which will cause the racing thread to return -ENXIO if the initialising
thread fails unexpectedly.

Cc: Hillf Danton <hdanton@sina.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: syzbot+82defefbbd8527e1c2cb@syzkaller.appspotmail.com
Signed-off-by: Will Deacon <will@kernel.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191219120203.32691-1-will@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-06 20:10:26 +01:00
Gang He b73eba2a86 ocfs2: fix the crash due to call ocfs2_get_dlm_debug once less
Because ocfs2_get_dlm_debug() function is called once less here, ocfs2
file system will trigger the system crash, usually after ocfs2 file
system is unmounted.

This system crash is caused by a generic memory corruption, these crash
backtraces are not always the same, for exapmle,

    ocfs2: Unmounting device (253,16) on (node 172167785)
    general protection fault: 0000 [#1] SMP PTI
    CPU: 3 PID: 14107 Comm: fence_legacy Kdump:
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
    RIP: 0010:__kmalloc+0xa5/0x2a0
    Code: 00 00 4d 8b 07 65 4d 8b
    RSP: 0018:ffffaa1fc094bbe8 EFLAGS: 00010286
    RAX: 0000000000000000 RBX: d310a8800d7a3faf RCX: 0000000000000000
    RDX: 0000000000000000 RSI: 0000000000000dc0 RDI: ffff96e68fc036c0
    RBP: d310a8800d7a3faf R08: ffff96e6ffdb10a0 R09: 00000000752e7079
    R10: 000000000001c513 R11: 0000000004091041 R12: 0000000000000dc0
    R13: 0000000000000039 R14: ffff96e68fc036c0 R15: ffff96e68fc036c0
    FS:  00007f699dfba540(0000) GS:ffff96e6ffd80000(0000) knlGS:00000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 000055f3a9d9b768 CR3: 000000002cd1c000 CR4: 00000000000006e0
    Call Trace:
     ext4_htree_store_dirent+0x35/0x100 [ext4]
     htree_dirblock_to_tree+0xea/0x290 [ext4]
     ext4_htree_fill_tree+0x1c1/0x2d0 [ext4]
     ext4_readdir+0x67c/0x9d0 [ext4]
     iterate_dir+0x8d/0x1a0
     __x64_sys_getdents+0xab/0x130
     do_syscall_64+0x60/0x1f0
     entry_SYSCALL_64_after_hwframe+0x49/0xbe
    RIP: 0033:0x7f699d33a9fb

This regression problem was introduced by commit e581595ea2 ("ocfs: no
need to check return value of debugfs_create functions").

Link: http://lkml.kernel.org/r/20191225061501.13587-1-ghe@suse.com
Fixes: e581595ea2 ("ocfs: no need to check return value of debugfs_create functions")
Signed-off-by: Gang He <ghe@suse.com>
Acked-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>	[5.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-04 13:55:09 -08:00
Kai Li 397eac17f8 ocfs2: call journal flush to mark journal as empty after journal recovery when mount
If journal is dirty when mount, it will be replayed but jbd2 sb log tail
cannot be updated to mark a new start because journal->j_flag has
already been set with JBD2_ABORT first in journal_init_common.

When a new transaction is committed, it will be recored in block 1
first(journal->j_tail is set to 1 in journal_reset).  If emergency
restart happens again before journal super block is updated
unfortunately, the new recorded trans will not be replayed in the next
mount.

The following steps describe this procedure in detail.
1. mount and touch some files
2. these transactions are committed to journal area but not checkpointed
3. emergency restart
4. mount again and its journals are replayed
5. journal super block's first s_start is 1, but its s_seq is not updated
6. touch a new file and its trans is committed but not checkpointed
7. emergency restart again
8. mount and journal is dirty, but trans committed in 6 will not be
replayed.

This exception happens easily when this lun is used by only one node.
If it is used by multi-nodes, other node will replay its journal and its
journal super block will be updated after recovery like what this patch
does.

ocfs2_recover_node->ocfs2_replay_journal.

The following jbd2 journal can be generated by touching a new file after
journal is replayed, and seq 15 is the first valid commit, but first seq
is 13 in journal super block.

logdump:
  Block 0: Journal Superblock
  Seq: 0   Type: 4 (JBD2_SUPERBLOCK_V2)
  Blocksize: 4096   Total Blocks: 32768   First Block: 1
  First Commit ID: 13   Start Log Blknum: 1
  Error: 0
  Feature Compat: 0
  Feature Incompat: 2 block64
  Feature RO compat: 0
  Journal UUID: 4ED3822C54294467A4F8E87D2BA4BC36
  FS Share Cnt: 1   Dynamic Superblk Blknum: 0
  Per Txn Block Limit    Journal: 0    Data: 0

  Block 1: Journal Commit Block
  Seq: 14   Type: 2 (JBD2_COMMIT_BLOCK)

  Block 2: Journal Descriptor
  Seq: 15   Type: 1 (JBD2_DESCRIPTOR_BLOCK)
  No. Blocknum        Flags
   0. 587             none
  UUID: 00000000000000000000000000000000
   1. 8257792         JBD2_FLAG_SAME_UUID
   2. 619             JBD2_FLAG_SAME_UUID
   3. 24772864        JBD2_FLAG_SAME_UUID
   4. 8257802         JBD2_FLAG_SAME_UUID
   5. 513             JBD2_FLAG_SAME_UUID JBD2_FLAG_LAST_TAG
  ...
  Block 7: Inode
  Inode: 8257802   Mode: 0640   Generation: 57157641 (0x3682809)
  FS Generation: 2839773110 (0xa9437fb6)
  CRC32: 00000000   ECC: 0000
  Type: Regular   Attr: 0x0   Flags: Valid
  Dynamic Features: (0x1) InlineData
  User: 0 (root)   Group: 0 (root)   Size: 7
  Links: 1   Clusters: 0
  ctime: 0x5de5d870 0x11104c61 -- Tue Dec  3 11:37:20.286280801 2019
  atime: 0x5de5d870 0x113181a1 -- Tue Dec  3 11:37:20.288457121 2019
  mtime: 0x5de5d870 0x11104c61 -- Tue Dec  3 11:37:20.286280801 2019
  dtime: 0x0 -- Thu Jan  1 08:00:00 1970
  ...
  Block 9: Journal Commit Block
  Seq: 15   Type: 2 (JBD2_COMMIT_BLOCK)

The following is journal recovery log when recovering the upper jbd2
journal when mount again.

syslog:
  ocfs2: File system on device (252,1) was not unmounted cleanly, recovering it.
  fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 0
  fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 1
  fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 2
  fs/jbd2/recovery.c:(jbd2_journal_recover, 278): JBD2: recovery, exit status 0, recovered transactions 13 to 13

Due to first commit seq 13 recorded in journal super is not consistent
with the value recorded in block 1(seq is 14), journal recovery will be
terminated before seq 15 even though it is an unbroken commit, inode
8257802 is a new file and it will be lost.

Link: http://lkml.kernel.org/r/20191217020140.2197-1-li.kai4@h3c.com
Signed-off-by: Kai Li <li.kai4@h3c.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Changwei Ge <gechangwei@live.cn>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-04 13:55:09 -08:00