Commit Graph

67382 Commits

Author SHA1 Message Date
Christoph Hellwig
977115c0f6 block: stop using bdget_disk for partition 0
We can just dereference the point in struct gendisk instead.  Also
remove the now unused export.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
0d02129e76 block: merge struct block_device and struct hd_struct
Instead of having two structures that represent each block device with
different life time rules, merge them into a single one.  This also
greatly simplifies the reference counting rules, as we can use the inode
reference count as the main reference count for the new struct
block_device, with the device model reference front ending it for device
model interaction.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
9499ffc752 f2fs: remove a few bd_part checks
bd_part is never NULL for a block device in use by a file system, so
remove the checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
8446fe9255 block: switch partition lookup to use struct block_device
Use struct block_device to lookup partitions on a disk.  This removes
all usage of struct hd_struct from the I/O path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de>			[bcache]
Acked-by: Chao Yu <yuchao0@huawei.com>			[f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
cb8432d650 block: allocate struct hd_struct as part of struct bdev_inode
Allocate hd_struct together with struct block_device to pre-load
the lifetime rule changes in preparation of merging the two structures.

Note that part0 was previously embedded into struct gendisk, but is
a separate allocation now, and already points to the block_device instead
of the hd_struct.  The lifetime of struct gendisk is still controlled by
the struct device embedded in the part0 hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
1bdd5ae025 block: move holder_dir to struct block_device
Move the holder_dir field to struct block_device in preparation for
kill struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
231926dbf0 block: move the partition_meta_info to struct block_device
Move the partition_meta_info to struct block_device in preparation for
killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
15e3d2c5cd block: move disk stat accounting to struct block_device
Move the dkstats and stamp field to struct block_device in preparation
of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
a782483cc1 block: remove the nr_sects field in struct hd_struct
Now that the hd_struct always has a block device attached to it, there is
no need for having two size field that just get out of sync.

Additionally the field in hd_struct did not use proper serialization,
possibly allowing for torn writes.  By only using the block_device field
this problem also gets fixed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de>			[bcache]
Acked-by: Chao Yu <yuchao0@huawei.com>			[f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
e6cb53827e block: initialize struct block_device in bdev_alloc
Don't play tricks with slab constructors as bdev structures tends to not
get reused very much, and this makes the code a lot less error prone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
37c3fc9abb block: simplify the block device claiming interface
Stop passing the whole device as a separate argument given that it
can be trivially deducted and cleanup the !holder debug check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
a954ea8120 block: remove ->bd_contains
Now that each hd_struct has a reference to the corresponding
block_device, there is no need for the bd_contains pointer.  Add
a bdev_whole() helper to look up the whole device block_device
struture instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
22ae8ce8b8 block: simplify bdev/disk lookup in blkdev_get
To simplify block device lookup and a few other upcoming areas, make sure
that we always have a struct block_device available for each disk and
each partition, and only find existing block devices in bdget.  The only
downside of this is that each device and partition uses a little more
memory.  The upside will be that a lot of code can be simplified.

With that all we need to look up the block device is to lookup the inode
and do a few sanity checks on the gendisk, instead of the separate lookup
for the gendisk.  For blk-cgroup which wants to access a gendisk without
opening it, a new blkdev_{get,put}_no_open low-level interface is added
to replace the previous get_gendisk use.

Note that the change to look up block device directly instead of the two
step lookup using struct gendisk causes a subtile change in behavior:
accessing a non-existing partition on an existing block device can now
cause a call to request_module.  That call is harmless, and in practice
no recent system will access these nodes as they aren't created by udev
and static /dev/ setups are unusual.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
4e7b5671c6 block: remove i_bdev
Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case).  This means that
we now don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de>		[bcache]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
7918f0f6fd block: opencode devcgroup_inode_permission
Just call devcgroup_check_permission to avoid various superflous checks
and a double conversion of the access flags.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
63d9932cae block: move bdput() to the callers of __blkdev_get
This will allow for a more symmetric calling convention going forward.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
5b56b6ed57 block: refactor blkdev_get
Move more code that is only run on the outer open but not the open of
the underlying whole device when opening a partition into blkdev_get,
which leads to a much easier to follow structure.

This allows to simplify the disk and module refcounting so that one
reference is held for each open, similar to what we do with normal
file operations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
ec5d451438 block: refactor __blkdev_put
Reorder the code to have one big section for the last close, and to use
bdev_is_partition.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
3a4174e686 block: switch bdgrab to use igrab
All of the current callers already have a reference, but to prepare for
additional users ensure bdgrab returns NULL if the block device is being
freed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
612c6aa781 block: change the hash used for looking up block devices
Adding the minor to the major creates tons of pointless conflicts. Just
use the dev_t itself, which is 32-bits and thus is guaranteed to fit
into ino_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
8d65269fe8 block: add a bdev_kobj helper
Add a little helper to find the kobject for a struct block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de>		[bcache]
Acked-by: David Sterba <dsterba@suse.com>	[btrfs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Christoph Hellwig
040f04bd2e fs: simplify freeze_bdev/thaw_bdev
Store the frozen superblock in struct block_device to avoid the awkward
interface that can return a sb only used a cookie, an ERR_PTR or NULL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Chao Yu <yuchao0@huawei.com>		[f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:38 -07:00
Christoph Hellwig
60b498852b fs: remove get_super_thawed and get_super_exclusive_thawed
Just open code the wait in the only caller of both functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:38 -07:00
Christoph Hellwig
5a5678ff3a block: unexport revalidate_disk_size
revalidate_disk_size is now only called from set_capacity_and_notify,
so drop the export.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-16 08:34:15 -07:00
Christoph Hellwig
99473d9db9 block: remove the call to __invalidate_device in check_disk_size_change
__invalidate_device without the kill_dirty parameter just invalidates
various clean entries in caches, which doesn't really help us with
anything, but can cause all kinds of horrible lock orders due to how
it calls into the file system.  The only reason this hasn't been a
major issue is because so many people use partitions, for which no
invalidation was performed anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-16 08:34:14 -07:00
Linus Torvalds
e28c0d7c92 Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "14 patches.

  Subsystems affected by this patch series: mm (migration, vmscan, slub,
  gup, memcg, hugetlbfs), mailmap, kbuild, reboot, watchdog, panic, and
  ocfs2"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  ocfs2: initialize ip_next_orphan
  panic: don't dump stack twice on warn
  hugetlbfs: fix anon huge page migration race
  mm: memcontrol: fix missing wakeup polling thread
  kernel/watchdog: fix watchdog_allowed_mask not used warning
  reboot: fix overflow parsing reboot cpu number
  Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint"
  compiler.h: fix barrier_data() on clang
  mm/gup: use unpin_user_pages() in __gup_longterm_locked()
  mm/slub: fix panic in slab_alloc_node()
  mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov
  mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit
  mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
  mm/compaction: count pages and stop correctly during page isolation
2020-11-14 12:35:11 -08:00
David Howells
3ad216ee73 afs: Fix afs_write_end() when called with copied == 0 [ver #3]
When afs_write_end() is called with copied == 0, it tries to set the
dirty region, but there's no way to actually encode a 0-length region in
the encoding in page->private.

"0,0", for example, indicates a 1-byte region at offset 0.  The maths
miscalculates this and sets it incorrectly.

Fix it to just do nothing but unlock and put the page in this case.  We
don't actually need to mark the page dirty as nothing presumably
changed.

Fixes: 65dd2d6072 ("afs: Alter dirty range encoding in page->private")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:51:18 -08:00
Wengang Wang
f5785283dd ocfs2: initialize ip_next_orphan
Though problem if found on a lower 4.1.12 kernel, I think upstream has
same issue.

In one node in the cluster, there is the following callback trace:

   # cat /proc/21473/stack
   __ocfs2_cluster_lock.isra.36+0x336/0x9e0 [ocfs2]
   ocfs2_inode_lock_full_nested+0x121/0x520 [ocfs2]
   ocfs2_evict_inode+0x152/0x820 [ocfs2]
   evict+0xae/0x1a0
   iput+0x1c6/0x230
   ocfs2_orphan_filldir+0x5d/0x100 [ocfs2]
   ocfs2_dir_foreach_blk+0x490/0x4f0 [ocfs2]
   ocfs2_dir_foreach+0x29/0x30 [ocfs2]
   ocfs2_recover_orphans+0x1b6/0x9a0 [ocfs2]
   ocfs2_complete_recovery+0x1de/0x5c0 [ocfs2]
   process_one_work+0x169/0x4a0
   worker_thread+0x5b/0x560
   kthread+0xcb/0xf0
   ret_from_fork+0x61/0x90

The above stack is not reasonable, the final iput shouldn't happen in
ocfs2_orphan_filldir() function.  Looking at the code,

  2067         /* Skip inodes which are already added to recover list, since dio may
  2068          * happen concurrently with unlink/rename */
  2069         if (OCFS2_I(iter)->ip_next_orphan) {
  2070                 iput(iter);
  2071                 return 0;
  2072         }
  2073

The logic thinks the inode is already in recover list on seeing
ip_next_orphan is non-NULL, so it skip this inode after dropping a
reference which incremented in ocfs2_iget().

While, if the inode is already in recover list, it should have another
reference and the iput() at line 2070 should not be the final iput
(dropping the last reference).  So I don't think the inode is really in
the recover list (no vmcore to confirm).

Note that ocfs2_queue_orphans(), though not shown up in the call back
trace, is holding cluster lock on the orphan directory when looking up
for unlinked inodes.  The on disk inode eviction could involve a lot of
IOs which may need long time to finish.  That means this node could hold
the cluster lock for very long time, that can lead to the lock requests
(from other nodes) to the orhpan directory hang for long time.

Looking at more on ip_next_orphan, I found it's not initialized when
allocating a new ocfs2_inode_info structure.

This causes te reflink operations from some nodes hang for very long
time waiting for the cluster lock on the orphan directory.

Fix: initialize ip_next_orphan as NULL.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-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>
Link: https://lkml.kernel.org/r/20201109171746.27884-1-wen.gang.wang@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14 11:26:04 -08:00
Linus Torvalds
f01c30de86 More VFS fixes for 5.10-rc4:
- Minor cleanups of the sb_start_* fs freeze helpers.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEUzaAxoMeQq6m2jMV+H93GTRKtOsFAl+sDaIACgkQ+H93GTRK
 tOu4sw//bIdBw11YfI9sPtMJR/RkK3lm/pU4A/eJYGD65Mzk8J4kNi6jXKuyqQ8e
 /RpTqKWOwVW05Qg5HlKTxXRyr5Q788+EuBQH2t8VukWVdAgK2TFvNTTXb7QDsNSD
 SneC7Sox3CEO+vYnBsr7tUjfl7AYH0uFTxLkvpYqSQBn2+jo2x0s7NyKKZSDAASI
 +Rmhinw4QjjAHYC54nBy6Q47XhrZJj7XCODJdEql81cKSJUvjCo3url3sNvGXXNW
 oXbs5IO5cVQrQx6n9rQxCfkN1dz9c/CBopYFwdgmg76Bj4VLSzCYVecnMeDl53pV
 3jXesNtJcR2dz64e98K1Moof2dHSm0/NP0Q7KnMYEaGEl6tAtyjSx9lL2Qd6npG+
 mG460UHd/7RHXoH/BTaCrtHHyA4pApHMqf+w3R2ienxrltKUJAEfGM/5x8o0ikWx
 laeT0L/m6Yv/dGnDvNthhoF84tCiQUnxg+UeXiKv4R9uFL1bKMFPw5i1zWuXqqaX
 yZPqUY1tiecQskr89AimOVI64L2MJ4DgBey1JzNL/XzPtw55Qu+LR6MkkaIC08Wu
 ubGJTm6fPw3Cz8JYgn4WIgKB9Q7yAoKsyl0mGLQh2SJT1FS8WLct+SRPwXcMVfJT
 VpkgjJW/ak5L+XfQU6Ev39zUasEAqdaxvPoTxUfne6spUiNbgrk=
 =ZC9a
 -----END PGP SIGNATURE-----

Merge tag 'vfs-5.10-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull fs freeze fix and cleanups from Darrick Wong:
 "A single vfs fix for 5.10, along with two subsequent cleanups.

  A very long time ago, a hack was added to the vfs fs freeze protection
  code to work around lockdep complaints about XFS, which would try to
  run a transaction (which requires intwrite protection) to finalize an
  xfs freeze (by which time the vfs had already taken intwrite).

  Fast forward a few years, and XFS fixed the recursive intwrite problem
  on its own, and the hack became unnecessary. Fast forward almost a
  decade, and latent bugs in the code converting this hack from freeze
  flags to freeze locks combine with lockdep bugs to make this reproduce
  frequently enough to notice page faults racing with freeze.

  Since the hack is unnecessary and causes thread race errors, just get
  rid of it completely. Making this kind of vfs change midway through a
  cycle makes me nervous, but a large enough number of the usual
  VFS/ext4/XFS/btrfs suspects have said this looks good and solves a
  real problem vector.

  And once that removal is done, __sb_start_write is now simple enough
  that it becomes possible to refactor the function into smaller,
  simpler static inline helpers in linux/fs.h. The cleanup is
  straightforward.

  Summary:

   - Finally remove the "convert to trylock" weirdness in the fs freezer
     code. It was necessary 10 years ago to deal with nested
     transactions in XFS, but we've long since removed that; and now
     this is causing subtle race conditions when lockdep goes offline
     and sb_start_* aren't prepared to retry a trylock failure.

   - Minor cleanups of the sb_start_* fs freeze helpers"

* tag 'vfs-5.10-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: move __sb_{start,end}_write* to fs.h
  vfs: separate __sb_start_write into blocking and non-blocking helpers
  vfs: remove lockdep bogosity in __sb_start_write
2020-11-13 16:07:53 -08:00
Linus Torvalds
d9315f5634 Fixes for 5.10-rc4:
- Fix a fairly serious problem where the reverse mapping btree key
 comparison functions were silently ignoring parts of the keyspace when
 doing comparisons.
 - Fix a thinko in the online refcount scrubber.
 - Fix a missing unlock in the pnfs code.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEUzaAxoMeQq6m2jMV+H93GTRKtOsFAl+sDJYACgkQ+H93GTRK
 tOtQOg//ZMCNB9wN/xZxlFHYIxD/AwnzuiVrfbQTT38JNg9fR9aHJxPcEbovplq+
 QosISoi/ooTbiyIz9p31RbGPGH7y26Oo9CcENWgVkiOdI6KTW0v41181/gAWpegQ
 u9V9aTARb2cerKVSc/TONitOgkzEu69J4GoG2A6pbWyCoUKvOrne9+v785BjpHdU
 3IdT30DQiW8QZodSww+i42fRrZhpkkmIELbZV7PKTCIJXRifAr2oAE5CBQaFHJri
 gh1Wgc7snn+fiQ8xLsG7u+Zl1bS6dC7wO8YksSX77V9CeaHvbAJxh16rBXXdaHAi
 TR5rymJ1+VB5SD9yVTyE7szQ9U6eo8nMktxxP6/Iejy6IiYSV0C/eQtKx/aYt6lU
 ZjoKnwxsiNXw6K+f+6AIFfPP3M4OmtOoQK8mzsl1rNVY6P3ZUtZQ0GoCnjPOtyfa
 PChG6eDzCcNVRUpzPAcVhxBWi8ilyMtEjJps+aBm5NQGnuyZ+PSZDLxYZCq5mOik
 m9uvIYDRvi6l9StShxi2DtcrYD665ZPWDAMeYXV1CxockjqdbMn+j+SiK6MJ0bzb
 9fL5IR+RphK3aZ4+U9PCJBPNK25Dd9rMaFIfb3FzZmokTDlBFovq26LCEshAH5rg
 WLZvynY3wF9TIqxnD8H9fGxNHJ5cbfR4tvMUOdXwCg0dAtFHoDI=
 =5qeU
 -----END PGP SIGNATURE-----

Merge tag 'xfs-5.10-fixes-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:

 - Fix a fairly serious problem where the reverse mapping btree key
   comparison functions were silently ignoring parts of the keyspace
   when doing comparisons

 - Fix a thinko in the online refcount scrubber

 - Fix a missing unlock in the pnfs code

* tag 'xfs-5.10-fixes-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix a missing unlock on error in xfs_fs_map_blocks
  xfs: fix brainos in the refcount scrubber's rmap fragment processor
  xfs: fix rmap key and record comparison functions
  xfs: set the unwritten bit in rmap lookup flags in xchk_bmap_get_rmapextents
  xfs: fix flags argument to rmap lookup when converting shared file rmaps
2020-11-13 16:01:44 -08:00
Linus Torvalds
1b1e9262ca io_uring-5.10-2020-11-13
-----BEGIN PGP SIGNATURE-----
 
 iQJEBAABCAAuFiEEwPw5LcreJtl1+l5K99NY+ylx4KYFAl+u9+4QHGF4Ym9lQGtl
 cm5lbC5kawAKCRD301j7KXHgpnyID/4kaa3gPcRhqCMZ2vSqQjwdMgKNON7b8Qh2
 Q9K/dsJn+jFDCKqZcX3hjG5kLziqRiIvMVtJfCYLm00p8hPfbxrmuK6iq1cxbkCg
 Jm9FqR/5O2ERMN+zQHZEccDhv0knnc33hLVAJLWneAH2enGMbPdvnOoez8ixfVCM
 IxEO5SRk0inrxgUOG5Qp78zqR+Znx3KQudpAJpYqP4/5T+59gI7yhkkvgiJDWlF8
 o+kMsiLHToVEoU/MTa/npfdEx+Ac+XryQ+3QAzMPL4miUHcgLwpF2cOZ02Op2hd1
 xf4/w4zwFRC9JGmgpBg26Woyen4e3o89RaB2lFrT/35PKwJU6u6UOUXYYrSoNt+m
 Yhr90mHqpS/iAQ2ejtEQVkgiXsjp4ovnocWcaqGhhh9k2NYbCaw35OtciWaCdOYW
 G4qnUClueV84XxYt3nzVUl99BkERoRUjiToG82L/4opO9FOAAXR/n4/a9R7ru4ZX
 FOE4H52r+PVsgpkAFiR0fX8BY44SSXoRQ3RPmns0iJpQBYS+R7GJpzvdU8Hfd+5j
 rrdD+XGZmhft39E1Yz2Ejtb805spoDHo08oHvVRMWdlmYFP09nNsqgcQOVksiAm1
 t5Dn5PMBjoFffPIaQDDKZqPM11tYk3pFV9VIx8u9tS0jqPsoY/I7p8l0zcOMz4pc
 NaG0aeY82w==
 =FEw9
 -----END PGP SIGNATURE-----

Merge tag 'io_uring-5.10-2020-11-13' of git://git.kernel.dk/linux-block

Pull io_uring fix from Jens Axboe:
 "A single fix in here, for a missed rounding case at setup time, which
  caused an otherwise legitimate setup case to return -EINVAL if used
  with unaligned ring size values"

* tag 'io_uring-5.10-2020-11-13' of git://git.kernel.dk/linux-block:
  io_uring: round-up cq size before comparing with rounded sq size
2020-11-13 15:05:19 -08:00
Linus Torvalds
d3ba7afcc1 Two ext4 bug fixes, one via a revert of a commit sent during the merge window.
-----BEGIN PGP SIGNATURE-----
 
 iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAl+t+7EACgkQ8vlZVpUN
 gaN6nQf+OzMMrP/QWF6fRG/ocQTgm4UZ/lo3REfZa8dRrFH+6qjtoFrmSnK7e+MJ
 V+639IYvHknDEgvap2yF8S6g06nAqb2HeSCHnkxdS3tCh5ZLgo2XmFOtB/WxZLnU
 Cx8dv9kw+mWJPdoRqJ+A4jn5cW2j3VLGNyJIdyIikkTb8L92fZRa/jKVZeIb84xX
 FEyshnzb3rV6ba0XdE99gWkabIAnnIsSwkF6SPhcqJpI3Lt1jkkV3D5h6DDoDz8d
 YpIA/6oPhEM2KwRgx9RJPdNRzHgmwWr2ti/0YLqlLNHWz1oZqi9K6yimXCfccwSU
 oCdK38tMWAFNiOGaijYx5xS3oNV+Dg==
 =9MzH
 -----END PGP SIGNATURE-----

Merge tag 'ext4_for_linus_bugfixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Two ext4 bug fixes, one being a revert of a commit sent during the
  merge window"

* tag 'ext4_for_linus_bugfixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  Revert "ext4: fix superblock checksum calculation race"
  ext4: handle dax mount option collision
2020-11-13 09:05:33 -08:00
Linus Torvalds
585e5b17b9 another fscrypt fix for 5.10-rc4
Fix a regression where new files weren't using inline encryption when
 they should be.
 -----BEGIN PGP SIGNATURE-----
 
 iIoEABYIADIWIQSacvsUNc7UX4ntmEPzXCl4vpKOKwUCX63AIhQcZWJpZ2dlcnNA
 Z29vZ2xlLmNvbQAKCRDzXCl4vpKOKzlsAP9/m9XfxW3SwG4D1dnajXQPNZgsaby2
 AxkqJyjxq3kBvQEAo8fPe8uURAzYBA9C5tcP0+QCB3jqZkHu0HVCeQKvXwI=
 =zldW
 -----END PGP SIGNATURE-----

Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fscrypt fix from Eric Biggers:
 "Fix a regression where new files weren't using inline encryption when
  they should be"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: fix inline encryption not used on new files
2020-11-12 16:39:58 -08:00
Linus Torvalds
20ca21dfcc Fix jdata data corruption and glock reference leak
-----BEGIN PGP SIGNATURE-----
 
 iQJIBAABCAAyFiEEJZs3krPW0xkhLMTc1b+f6wMTZToFAl+ttO4UHGFncnVlbmJh
 QHJlZGhhdC5jb20ACgkQ1b+f6wMTZTqAdg//Xssi+p1N13BfAdyYdPoqEQ9JKSZH
 vEwth53ASsEy+WXz7TMulmrwJXWyQXfEibPvGLrHZZ0zgdw3DyLqGCnDCJOqmdOQ
 /e08MmJ9LdGz06IHnlzhWj3Lm4KpJaFzil4HBYE8Jlu4PimLVKcIQoDRRMV2DURl
 arPSm/dJtqUFVDj9+bawq5mRmxA0gXPFspf857wnDzNB+hGlll2wvK70vapNlg39
 hNVjDMfhb04CVNsJoVZS4wRI3TlwvOjlxB9WKvNvyRDF1jQT8bSX8UJyq5Qupf+K
 /HJvZFrm0gv6W0Z9UFMy5JXIQ5NTriBzrdu5rgzhKPA/r8oV0/8i0pq/macXHOQF
 shPNZQXdsN6uCK57JNugSW6C96l2K4kP7rOSjTE6N0WFo9y/u2bCAbo0+hh0lvns
 2sSKLX2ZtVwvyy0LVcAJa0Q1ZU9CK5F4J8F2Zy3DFOJqV1GuRCh0LBgyWoL4jJEQ
 J3JLJdUevP7E7dvXIwzsDNWOUiRy0xAqFQOIcdvt4WhMsH7QsHIiYjodHFLKx2qq
 Xk9YSTua7A+UjpLDyt2iMbumplMomQqx72NLUM5Kv9r+kSId4Ird/Q8HYHvWezzY
 xUjIvOAMXI/ZKsrJRwE0V2xI+q2wmHPFYrBjl0CymWsCksc9kB1wzkqQYp/Tcxxm
 hhp3iPPY/mEXr4s=
 =bTtI
 -----END PGP SIGNATURE-----

Merge tag 'gfs2-v5.10-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 fixes from Andreas Gruenbacher:
 "Fix jdata data corruption and glock reference leak"

* tag 'gfs2-v5.10-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix case in which ail writes are done to jdata holes
  Revert "gfs2: Ignore journal log writes for jdata holes"
  gfs2: fix possible reference leak in gfs2_check_blk_type
2020-11-12 16:37:14 -08:00
Linus Torvalds
200f9d21aa NFS Client Bugfixes for Linux 5.10-rc4
- Stable fixes:
   - Fix failure to unregister shrinker
 
 - Other fixes:
   - Fix unnecessary locking to clear up some contention
   - Fix listxattr receive buffer size
   - Fix default mount options for nfsroot
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEnZ5MQTpR7cLU7KEp18tUv7ClQOsFAl+tbGIACgkQ18tUv7Cl
 QOvRyxAA4YXD1dlnO2Xbqo7ZyrgoZkVn08rb9yloeCuCNJDZPDSXt2QHAKdbmMU+
 8dxpcWN/8RUEUJK3cccNf2+XV/AWqqaFnFXylcfXLUnjZx0f30ou+HO+BRZFInVd
 OgG3njO94jV1B3RK38J7jyVRqx3hd0Vkq9Ja4LVF2l/x9ueGrj+pOdNauWr1JhFo
 6l4Fk2PKakLKJGsxLXmKlBb7p+EEwKa1qRov8SED33uTZkSnbFOmbxtEp1bu7sQx
 UKBTLADny9FClA1sjM45XN2nLS99/uUl/CaRKm/GB5nP4WKG4J3HgziAAvVglHcP
 yrUIiwLaUGZvteiO5O6NJqZpk6NyzWnBo4ZDt/TZcQ5nvK7uD6buUbDFFn++lbKm
 qwVWCnsme7sx3zVLLS4pY2GXnNNkGozjyrQOV0NQx1QphfalKsXHxeXikY+dkXr5
 FZwKodWxiKlsZj8cyOVjrm9q3+EsBnW8FyitgVQH4QIvcU9Z9zdB5QFyy7KsG4bw
 3iKsbz4HsJ0K10m7ykNEcR5R6XQBnFVWGxAHkQ3qbxzw9hYvhEebP/N2P7x3DC1X
 3gVPDto03Vc5PsuGoXm50kqXpRD3w+fnpf+HMZFmRbqjanqBHvgyYu58Zy0fXEnQ
 VigUcvsjAJhmoneahO3va8HF3a70PPqhzTTVKtfORBNg9uHmS1M=
 =7a8T
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-5.10-2' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client bugfixes from Anna Schumaker:
 "Stable fixes:
  - Fix failure to unregister shrinker

  Other fixes:
  - Fix unnecessary locking to clear up some contention
  - Fix listxattr receive buffer size
  - Fix default mount options for nfsroot"

* tag 'nfs-for-5.10-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS: Remove unnecessary inode lock in nfs_fsync_dir()
  NFS: Remove unnecessary inode locking in nfs_llseek_dir()
  NFS: Fix listxattr receive buffer size
  NFSv4.2: fix failure to unregister shrinker
  nfsroot: Default mount option should ask for built-in NFS version
2020-11-12 13:49:12 -08:00
Bob Peterson
4e79e3f08e gfs2: Fix case in which ail writes are done to jdata holes
Patch b2a846dbef ("gfs2: Ignore journal log writes for jdata holes")
tried (unsuccessfully) to fix a case in which writes were done to jdata
blocks, the blocks are sent to the ail list, then a punch_hole or truncate
operation caused the blocks to be freed. In other words, the ail items
are for jdata holes. Before b2a846dbef, the jdata hole caused function
gfs2_block_map to return -EIO, which was eventually interpreted as an
IO error to the journal, and then withdraw.

This patch changes function gfs2_get_block_noalloc, which is only used
for jdata writes, so it returns -ENODATA rather than -EIO, and when
-ENODATA is returned to gfs2_ail1_start_one, the error is ignored.
We can safely ignore it because gfs2_ail1_start_one is only called
when the jdata pages have already been written and truncated, so the
ail1 content no longer applies.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-11-12 18:55:20 +01:00
Bob Peterson
d3039c0615 Revert "gfs2: Ignore journal log writes for jdata holes"
This reverts commit b2a846dbef.

That commit changed the behavior of function gfs2_block_map to return
-ENODATA in cases where a hole (IOMAP_HOLE) is encountered and create is
false.  While that fixed the intended problem for jdata, it also broke
other callers of gfs2_block_map such as some jdata block reads.  Before
the patch, an encountered hole would be skipped and the buffer seen as
unmapped by the caller.  The patch changed the behavior to return
-ENODATA, which is interpreted as an error by the caller.

The -ENODATA return code should be restricted to the specific case where
jdata holes are encountered during ail1 writes.  That will be done in a
later patch.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-11-12 18:41:57 +01:00
Trond Myklebust
11decaf812 NFS: Remove unnecessary inode lock in nfs_fsync_dir()
nfs_inc_stats() is already thread-safe, and there are no other reasons
to hold the inode lock here.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-11-12 10:41:26 -05:00
Trond Myklebust
83f2c45e63 NFS: Remove unnecessary inode locking in nfs_llseek_dir()
Remove the contentious inode lock, and instead provide thread safety
using the file->f_lock spinlock.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-11-12 10:41:26 -05:00
Chuck Lever
6c2190b3fc NFS: Fix listxattr receive buffer size
Certain NFSv4.2/RDMA tests fail with v5.9-rc1.

rpcrdma_convert_kvec() runs off the end of the rl_segments array
because rq_rcv_buf.tail[0].iov_len holds a very large positive
value. The resultant kernel memory corruption is enough to crash
the client system.

Callers of rpc_prepare_reply_pages() must reserve an extra XDR_UNIT
in the maximum decode size for a possible XDR pad of the contents
of the xdr_buf's pages. That guarantees the allocated receive buffer
will be large enough to accommodate the usual contents plus that XDR
pad word.

encode_op_hdr() cannot add that extra word. If it does,
xdr_inline_pages() underruns the length of the tail iovec.

Fixes: 3e1f02123f ("NFSv4.2: add client side XDR handling for extended attributes")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-11-12 10:41:26 -05:00
J. Bruce Fields
70438afbf1 NFSv4.2: fix failure to unregister shrinker
We forgot to unregister the nfs4_xattr_large_entry_shrinker.

That leaves the global list of shrinkers corrupted after unload of the
nfs module, after which possibly unrelated code that calls
register_shrinker() or unregister_shrinker() gets a BUG() with
"supervisor write access in kernel mode".

And similarly for the nfs4_xattr_large_entry_lru.

Reported-by: Kris Karas <bugs-a17@moonlit-rail.com>
Tested-By: Kris Karas <bugs-a17@moonlit-rail.com>
Fixes: 95ad37f90c "NFSv4.2: add client side xattr caching."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-11-12 10:40:02 -05:00
Zhang Qilong
bc923818b1 gfs2: fix possible reference leak in gfs2_check_blk_type
In the fail path of gfs2_check_blk_type, forgetting to call
gfs2_glock_dq_uninit will result in rgd_gh reference leak.

Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-11-12 13:09:07 +01:00
Eric Biggers
d19d8d345e fscrypt: fix inline encryption not used on new files
The new helper function fscrypt_prepare_new_inode() runs before
S_ENCRYPTED has been set on the new inode.  This accidentally made
fscrypt_select_encryption_impl() never enable inline encryption on newly
created files, due to its use of fscrypt_needs_contents_encryption()
which only returns true when S_ENCRYPTED is set.

Fix this by using S_ISREG() directly instead of
fscrypt_needs_contents_encryption(), analogous to what
select_encryption_mode() does.

I didn't notice this earlier because by design, the user-visible
behavior is the same (other than performance, potentially) regardless of
whether inline encryption is used or not.

Fixes: a992b20cd4 ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()")
Reviewed-by: Satya Tangirala <satyat@google.com>
Link: https://lore.kernel.org/r/20201111015224.303073-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-11-11 20:59:07 -08:00
Theodore Ts'o
d196e229a8 Revert "ext4: fix superblock checksum calculation race"
This reverts commit acaa532687 which can
result in a ext4_superblock_csum_set() trying to sleep while a
spinlock is being held.

For more discussion of this issue, please see:

https://lore.kernel.org/r/000000000000f50cb705b313ed70@google.com

Reported-by: syzbot+7a4ba6a239b91a126c28@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-11-11 14:24:18 -05:00
Harshad Shirwadkar
a72b38eebe ext4: handle dax mount option collision
Mount options dax=inode and dax=never collided with fast_commit and
journal checksum. Redefine the mount flags to remove the collision.

Reported-by: Murphy Zhou <jencce.kernel@gmail.com>
Fixes: 9cb20f94af ("fs/ext4: Make DAX mount option a tri-state")
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201111183209.447175-1-harshads@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-11-11 14:23:29 -05:00
Jens Axboe
88ec3211e4 io_uring: round-up cq size before comparing with rounded sq size
If an application specifies IORING_SETUP_CQSIZE to set the CQ ring size
to a specific size, we ensure that the CQ size is at least that of the
SQ ring size. But in doing so, we compare the already rounded up to power
of two SQ size to the as-of yet unrounded CQ size. This means that if an
application passes in non power of two sizes, we can return -EINVAL when
the final value would've been fine. As an example, an application passing
in 100/100 for sq/cq size should end up with 128 for both. But since we
round the SQ size first, we compare the CQ size of 100 to 128, and return
-EINVAL as that is too small.

Cc: stable@vger.kernel.org
Fixes: 33a107f0a1 ("io_uring: allow application controlled CQ ring size")
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-11 10:42:41 -07:00
Christoph Hellwig
2bd3fa793a xfs: fix a missing unlock on error in xfs_fs_map_blocks
We also need to drop the iolock when invalidate_inode_pages2 fails, not
only on all other error or successful cases.

Fixes: 527851124d ("xfs: implement pNFS export operations")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-11-11 08:07:37 -08:00
Darrick J. Wong
9b8523423b vfs: move __sb_{start,end}_write* to fs.h
Now that we've straightened out the callers, move these three functions
to fs.h since they're fairly trivial.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
2020-11-10 16:53:11 -08:00
Darrick J. Wong
8a3c84b649 vfs: separate __sb_start_write into blocking and non-blocking helpers
Break this function into two helpers so that it's obvious that the
trylock versions return a value that must be checked, and the blocking
versions don't require that.  While we're at it, clean up the return
type mismatch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-11-10 16:53:07 -08:00
Darrick J. Wong
22843291ef vfs: remove lockdep bogosity in __sb_start_write
__sb_start_write has some weird looking lockdep code that claims to
exist to handle nested freeze locking requests from xfs.  The code as
written seems broken -- if we think we hold a read lock on any of the
higher freeze levels (e.g. we hold SB_FREEZE_WRITE and are trying to
lock SB_FREEZE_PAGEFAULT), it converts a blocking lock attempt into a
trylock.

However, it's not correct to downgrade a blocking lock attempt to a
trylock unless the downgrading code or the callers are prepared to deal
with that situation.  Neither __sb_start_write nor its callers handle
this at all.  For example:

sb_start_pagefault ignores the return value completely, with the result
that if xfs_filemap_fault loses a race with a different thread trying to
fsfreeze, it will proceed without pagefault freeze protection (thereby
breaking locking rules) and then unlocks the pagefault freeze lock that
it doesn't own on its way out (thereby corrupting the lock state), which
leads to a system hang shortly afterwards.

Normally, this won't happen because our ownership of a read lock on a
higher freeze protection level blocks fsfreeze from grabbing a write
lock on that higher level.  *However*, if lockdep is offline,
lock_is_held_type unconditionally returns 1, which means that
percpu_rwsem_is_held returns 1, which means that __sb_start_write
unconditionally converts blocking freeze lock attempts into trylocks,
even when we *don't* hold anything that would block a fsfreeze.

Apparently this all held together until 5.10-rc1, when bugs in lockdep
caused lockdep to shut itself off early in an fstests run, and once
fstests gets to the "race writes with freezer" tests, kaboom.  This
might explain the long trail of vanishingly infrequent livelocks in
fstests after lockdep goes offline that I've never been able to
diagnose.

We could fix it by spinning on the trylock if wait==true, but AFAICT the
locking works fine if lockdep is not built at all (and I didn't see any
complaints running fstests overnight), so remove this snippet entirely.

NOTE: Commit f4b554af99 in 2015 created the current weird logic (which
used to exist in a different form in commit 5accdf82ba from 2012) in
__sb_start_write.  XFS solved this whole problem in the late 2.6 era by
creating a variant of transactions (XFS_TRANS_NO_WRITECOUNT) that don't
grab intwrite freeze protection, thus making lockdep's solution
unnecessary.  The commit claims that Dave Chinner explained that the
trylock hack + comment could be removed, but nobody ever did.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
2020-11-10 16:49:29 -08:00