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Commit Graph

9200 Commits

Author SHA1 Message Date
Randy Dunlap
260db43cd2 btrfs: delete duplicated words + other fixes in comments
Delete repeated words in fs/btrfs/.
{to, the, a, and old}
and change "into 2 part" to "into 2 parts".

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Qu Wenruo
437490fed3 btrfs: tracepoints: output proper root owner for trace_find_free_extent()
The current trace event always output result like this:

 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
 find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)

T's saying we're allocating data extent for EXTENT tree, which is not
even possible.

It's because we always use EXTENT tree as the owner for
trace_find_free_extent() without using the @root from
btrfs_reserve_extent().

This patch will change the parameter to use proper @root for
trace_find_free_extent():

Now it looks much better:

 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=4096 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=7(CSUM_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=1(ROOT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)

Reported-by: Hans van Kranenburg <hans@knorrie.org>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:49 +02:00
Linus Torvalds
4e3b9ce271 for-5.9-rc7-tag
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Merge tag 'for-5.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two more fixes.

  One is for a lockdep warning/lockup (also caught by syzbot), that one
  has been seen in practice. Regarding the other syzbot reports
  mentioned last time, they don't seem to be urgent and reliably
  reproducible so they'll be fixed later.

  The second fix is for a potential corruption when device replace
  finishes and the in-memory state of trim is not copied to the new
  device"

* tag 'for-5.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix filesystem corruption after a device replace
  btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
  btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing
2020-10-02 10:09:40 -07:00
Filipe Manana
4c8f353272 btrfs: fix filesystem corruption after a device replace
We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating a new
chunk. However after a device replace operation, we were not setting the
allocated ranges in the new device's allocation state tree, so that tree
is empty after a device replace.

This means that a fitrim operation after a device replace will trim the
device ranges that have allocated chunks and extents, as we trim every
range for which there is not a range marked in the device's allocation
state tree. It is also important during chunk allocation, since the
device's allocation state is used to determine if a range is already
allocated when allocating a new chunk.

This is trivial to reproduce and the following script triggers the bug:

  $ cat reproducer.sh
  #!/bin/bash

  DEV1="/dev/sdg"
  DEV2="/dev/sdh"
  DEV3="/dev/sdi"

  wipefs -a $DEV1 $DEV2 $DEV3 &> /dev/null

  # Create a raid1 test fs on 2 devices.
  mkfs.btrfs -f -m raid1 -d raid1 $DEV1 $DEV2 > /dev/null
  mount $DEV1 /mnt/btrfs

  xfs_io -f -c "pwrite -S 0xab 0 10M" /mnt/btrfs/foo

  echo "Starting to replace $DEV1 with $DEV3"
  btrfs replace start -B $DEV1 $DEV3 /mnt/btrfs
  echo

  echo "Running fstrim"
  fstrim /mnt/btrfs
  echo

  echo "Unmounting filesystem"
  umount /mnt/btrfs

  echo "Mounting filesystem in degraded mode using $DEV3 only"
  wipefs -a $DEV1 $DEV2 &> /dev/null
  mount -o degraded $DEV3 /mnt/btrfs
  if [ $? -ne 0 ]; then
          dmesg | tail
          echo
          echo "Failed to mount in degraded mode"
          exit 1
  fi

  echo
  echo "File foo data (expected all bytes = 0xab):"
  od -A d -t x1 /mnt/btrfs/foo

  umount /mnt/btrfs

When running the reproducer:

  $ ./replace-test.sh
  wrote 10485760/10485760 bytes at offset 0
  10 MiB, 2560 ops; 0.0901 sec (110.877 MiB/sec and 28384.5216 ops/sec)
  Starting to replace /dev/sdg with /dev/sdi

  Running fstrim

  Unmounting filesystem
  Mounting filesystem in degraded mode using /dev/sdi only
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/sdi, missing codepage or helper program, or other error.
  [19581.748641] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi started
  [19581.803842] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi finished
  [19582.208293] BTRFS info (device sdi): allowing degraded mounts
  [19582.208298] BTRFS info (device sdi): disk space caching is enabled
  [19582.208301] BTRFS info (device sdi): has skinny extents
  [19582.212853] BTRFS warning (device sdi): devid 2 uuid 1f731f47-e1bb-4f00-bfbb-9e5a0cb4ba9f is missing
  [19582.213904] btree_readpage_end_io_hook: 25839 callbacks suppressed
  [19582.213907] BTRFS error (device sdi): bad tree block start, want 30490624 have 0
  [19582.214780] BTRFS warning (device sdi): failed to read root (objectid=7): -5
  [19582.231576] BTRFS error (device sdi): open_ctree failed

  Failed to mount in degraded mode

So fix by setting all allocated ranges in the replace target device when
the replace operation is finishing, when we are holding the chunk mutex
and we can not race with new chunk allocations.

A test case for fstests follows soon.

Fixes: 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-30 19:40:51 +02:00
Josef Bacik
a466c85edc btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.  As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock.  Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.

There's a report from syzbot probably hitting one of the cases where
the bd_mutex and device_list_mutex are taken in the wrong order, however
it's not with device replace, like this patch fixes. As there's no
reproducer available so far, we can't verify the fix.

https://lore.kernel.org/lkml/000000000000fc04d105afcf86d7@google.com/
dashboard link: https://syzkaller.appspot.com/bug?extid=84a0634dc5d21d488419

  WARNING: possible circular locking dependency detected
  5.9.0-rc5-syzkaller #0 Not tainted
  ------------------------------------------------------
  syz-executor.0/6878 is trying to acquire lock:
  ffff88804c17d780 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804

  but task is already holding lock:
  ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 btrfs_finish_chunk_alloc+0x281/0xf90 fs/btrfs/volumes.c:5255
	 btrfs_create_pending_block_groups+0x2f3/0x700 fs/btrfs/block-group.c:2109
	 __btrfs_end_transaction+0xf5/0x690 fs/btrfs/transaction.c:916
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3807 [inline]
	 find_free_extent+0x23b7/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #3 (sb_internal#2){.+.+}-{0:0}:
	 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
	 __sb_start_write+0x234/0x470 fs/super.c:1672
	 sb_start_intwrite include/linux/fs.h:1690 [inline]
	 start_transaction+0xbe7/0x1170 fs/btrfs/transaction.c:624
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3789 [inline]
	 find_free_extent+0x25e1/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #2 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
	 __flush_work+0x60e/0xac0 kernel/workqueue.c:3041
	 wb_shutdown+0x180/0x220 mm/backing-dev.c:355
	 bdi_unregister+0x174/0x590 mm/backing-dev.c:872
	 del_gendisk+0x820/0xa10 block/genhd.c:933
	 loop_remove drivers/block/loop.c:2192 [inline]
	 loop_control_ioctl drivers/block/loop.c:2291 [inline]
	 loop_control_ioctl+0x3b1/0x480 drivers/block/loop.c:2257
	 vfs_ioctl fs/ioctl.c:48 [inline]
	 __do_sys_ioctl fs/ioctl.c:753 [inline]
	 __se_sys_ioctl fs/ioctl.c:739 [inline]
	 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (loop_ctl_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 lo_open+0x19/0xd0 drivers/block/loop.c:1893
	 __blkdev_get+0x759/0x1aa0 fs/block_dev.c:1507
	 blkdev_get fs/block_dev.c:1639 [inline]
	 blkdev_open+0x227/0x300 fs/block_dev.c:1753
	 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
	 do_open fs/namei.c:3251 [inline]
	 path_openat+0x1b9a/0x2730 fs/namei.c:3368
	 do_filp_open+0x17e/0x3c0 fs/namei.c:3395
	 do_sys_openat2+0x16d/0x420 fs/open.c:1168
	 do_sys_open fs/open.c:1184 [inline]
	 __do_sys_open fs/open.c:1192 [inline]
	 __se_sys_open fs/open.c:1188 [inline]
	 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&bdev->bd_mutex){+.+.}-{3:3}:
	 check_prev_add kernel/locking/lockdep.c:2496 [inline]
	 check_prevs_add kernel/locking/lockdep.c:2601 [inline]
	 validate_chain kernel/locking/lockdep.c:3218 [inline]
	 __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
	 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 blkdev_put+0x30/0x520 fs/block_dev.c:1804
	 btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
	 btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
	 btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
	 close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
	 close_fs_devices fs/btrfs/volumes.c:1193 [inline]
	 btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
	 close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
	 generic_shutdown_super+0x144/0x370 fs/super.c:464
	 kill_anon_super+0x36/0x60 fs/super.c:1108
	 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
	 deactivate_locked_super+0x94/0x160 fs/super.c:335
	 deactivate_super+0xad/0xd0 fs/super.c:366
	 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
	 task_work_run+0xdd/0x190 kernel/task_work.c:141
	 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
	 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
	 exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
	 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &bdev->bd_mutex --> sb_internal#2 --> &fs_devs->device_list_mutex

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_devs->device_list_mutex);
				 lock(sb_internal#2);
				 lock(&fs_devs->device_list_mutex);
    lock(&bdev->bd_mutex);

   *** DEADLOCK ***

  3 locks held by syz-executor.0/6878:
   #0: ffff88809070c0e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa5/0xd0 fs/super.c:365
   #1: ffffffff8a5b37a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x23/0x1f0 fs/btrfs/volumes.c:1178
   #2: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  stack backtrace:
  CPU: 0 PID: 6878 Comm: syz-executor.0 Not tainted 5.9.0-rc5-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:77 [inline]
   dump_stack+0x198/0x1fd lib/dump_stack.c:118
   check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827
   check_prev_add kernel/locking/lockdep.c:2496 [inline]
   check_prevs_add kernel/locking/lockdep.c:2601 [inline]
   validate_chain kernel/locking/lockdep.c:3218 [inline]
   __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
   lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
   __mutex_lock_common kernel/locking/mutex.c:956 [inline]
   __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
   blkdev_put+0x30/0x520 fs/block_dev.c:1804
   btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
   btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
   btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
   close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
   close_fs_devices fs/btrfs/volumes.c:1193 [inline]
   btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
   close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
   generic_shutdown_super+0x144/0x370 fs/super.c:464
   kill_anon_super+0x36/0x60 fs/super.c:1108
   btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
   deactivate_locked_super+0x94/0x160 fs/super.c:335
   deactivate_super+0xad/0xd0 fs/super.c:366
   cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
   task_work_run+0xdd/0x190 kernel/task_work.c:141
   tracehook_notify_resume include/linux/tracehook.h:188 [inline]
   exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
   exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
   syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x460027
  RSP: 002b:00007fff59216328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  RAX: 0000000000000000 RBX: 0000000000076035 RCX: 0000000000460027
  RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff592163d0
  RBP: 0000000000000333 R08: 0000000000000000 R09: 000000000000000b
  R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff59217460
  R13: 0000000002df2a60 R14: 0000000000000000 R15: 00007fff59217460

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add syzbot reference ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-30 19:34:24 +02:00
Josef Bacik
313b085851 btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing
We need to move the closing of the src_device out of all the device
replace locking, but we definitely want to zero out the superblock
before we commit the last time to make sure the device is properly
removed.  Handle this by pushing btrfs_scratch_superblocks into
btrfs_dev_replace_finishing, and then later on we'll move the src_device
closing and freeing stuff where we need it to be.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-25 16:40:22 +02:00
Linus Torvalds
bffac4b543 for-5.9-rc6-tag
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Merge tag 'for-5.9-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "syzkaller started to hit us with reports, here's a fix for one type
  (stack overflow when printing checksums on read error).

  The other patch is a fix for sysfs object, we have a test for that and
  it leads to a crash."

* tag 'for-5.9-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix put of uninitialized kobject after seed device delete
  btrfs: fix overflow when copying corrupt csums for a message
2020-09-23 14:32:23 -07:00
Anand Jain
b5ddcffa37 btrfs: fix put of uninitialized kobject after seed device delete
The following test case leads to NULL kobject free error:

  mount seed /mnt
  add sprout to /mnt
  umount /mnt
  mount sprout to /mnt
  delete seed

  kobject: '(null)' (00000000dd2b87e4): is not initialized, yet kobject_put() is being called.
  WARNING: CPU: 1 PID: 15784 at lib/kobject.c:736 kobject_put+0x80/0x350
  RIP: 0010:kobject_put+0x80/0x350
  ::
  Call Trace:
  btrfs_sysfs_remove_devices_dir+0x6e/0x160 [btrfs]
  btrfs_rm_device.cold+0xa8/0x298 [btrfs]
  btrfs_ioctl+0x206c/0x22a0 [btrfs]
  ksys_ioctl+0xe2/0x140
  __x64_sys_ioctl+0x1e/0x29
  do_syscall_64+0x96/0x150
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f4047c6288b
  ::

This is because, at the end of the seed device-delete, we try to remove
the seed's devid sysfs entry. But for the seed devices under the sprout
fs, we don't initialize the devid kobject yet. So add a kobject state
check, which takes care of the bug.

Fixes: 668e48af7a ("btrfs: sysfs, add devid/dev_state kobject and device attributes")
CC: stable@vger.kernel.org # 5.6+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-22 15:57:52 +02:00
Johannes Thumshirn
35be8851d1 btrfs: fix overflow when copying corrupt csums for a message
Syzkaller reported a buffer overflow in btree_readpage_end_io_hook()
when loop mounting a crafted image:

  detected buffer overflow in memcpy
  ------------[ cut here ]------------
  kernel BUG at lib/string.c:1129!
  invalid opcode: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 26 Comm: kworker/u4:2 Not tainted 5.9.0-rc4-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Workqueue: btrfs-endio-meta btrfs_work_helper
  RIP: 0010:fortify_panic+0xf/0x20 lib/string.c:1129
  RSP: 0018:ffffc90000e27980 EFLAGS: 00010286
  RAX: 0000000000000022 RBX: ffff8880a80dca64 RCX: 0000000000000000
  RDX: ffff8880a90860c0 RSI: ffffffff815dba07 RDI: fffff520001c4f22
  RBP: ffff8880a80dca00 R08: 0000000000000022 R09: ffff8880ae7318e7
  R10: 0000000000000000 R11: 0000000000077578 R12: 00000000ffffff6e
  R13: 0000000000000008 R14: ffffc90000e27a40 R15: 1ffff920001c4f3c
  FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000557335f440d0 CR3: 000000009647d000 CR4: 00000000001506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   memcpy include/linux/string.h:405 [inline]
   btree_readpage_end_io_hook.cold+0x206/0x221 fs/btrfs/disk-io.c:642
   end_bio_extent_readpage+0x4de/0x10c0 fs/btrfs/extent_io.c:2854
   bio_endio+0x3cf/0x7f0 block/bio.c:1449
   end_workqueue_fn+0x114/0x170 fs/btrfs/disk-io.c:1695
   btrfs_work_helper+0x221/0xe20 fs/btrfs/async-thread.c:318
   process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
   worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
   kthread+0x3b5/0x4a0 kernel/kthread.c:292
   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
  Modules linked in:
  ---[ end trace b68924293169feef ]---
  RIP: 0010:fortify_panic+0xf/0x20 lib/string.c:1129
  RSP: 0018:ffffc90000e27980 EFLAGS: 00010286
  RAX: 0000000000000022 RBX: ffff8880a80dca64 RCX: 0000000000000000
  RDX: ffff8880a90860c0 RSI: ffffffff815dba07 RDI: fffff520001c4f22
  RBP: ffff8880a80dca00 R08: 0000000000000022 R09: ffff8880ae7318e7
  R10: 0000000000000000 R11: 0000000000077578 R12: 00000000ffffff6e
  R13: 0000000000000008 R14: ffffc90000e27a40 R15: 1ffff920001c4f3c
  FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f95b7c4d008 CR3: 000000009647d000 CR4: 00000000001506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

The overflow happens, because in btree_readpage_end_io_hook() we assume
that we have found a 4 byte checksum instead of the real possible 32
bytes we have for the checksums.

With the fix applied:

[   35.726623] BTRFS: device fsid 815caf9a-dc43-4d2a-ac54-764b8333d765 devid 1 transid 5 /dev/loop0 scanned by syz-repro (215)
[   35.738994] BTRFS info (device loop0): disk space caching is enabled
[   35.738998] BTRFS info (device loop0): has skinny extents
[   35.743337] BTRFS warning (device loop0): loop0 checksum verify failed on 1052672 wanted 0xf9c035fc8d239a54 found 0x67a25c14b7eabcf9 level 0
[   35.743420] BTRFS error (device loop0): failed to read chunk root
[   35.745899] BTRFS error (device loop0): open_ctree failed

Reported-by: syzbot+e864a35d361e1d4e29a5@syzkaller.appspotmail.com
Fixes: d5178578bc ("btrfs: directly call into crypto framework for checksumming")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-21 12:39:21 +02:00
Linus Torvalds
fc4f28bb3d for-5.9-rc5-tag
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Merge tag 'for-5.9-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "One of the recent lockdep fixes introduced a bug that breaks the
  search ioctl, which is used by some applications (bees, compsize). The
  patch made it to stable trees so we need this fixup to make it work
  again"

* tag 'for-5.9-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix wrong address when faulting in pages in the search ioctl
2020-09-14 15:41:58 -07:00
Filipe Manana
1c78544eaa btrfs: fix wrong address when faulting in pages in the search ioctl
When faulting in the pages for the user supplied buffer for the search
ioctl, we are passing only the base address of the buffer to the function
fault_in_pages_writeable(). This means that after the first iteration of
the while loop that searches for leaves, when we have a non-zero offset,
stored in 'sk_offset', we try to fault in a wrong page range.

So fix this by adding the offset in 'sk_offset' to the base address of the
user supplied buffer when calling fault_in_pages_writeable().

Several users have reported that the applications compsize and bees have
started to operate incorrectly since commit a48b73eca4 ("btrfs: fix
potential deadlock in the search ioctl") was added to stable trees, and
these applications make heavy use of the search ioctls. This fixes their
issues.

Link: https://lore.kernel.org/linux-btrfs/632b888d-a3c3-b085-cdf5-f9bb61017d92@lechevalier.se/
Link: https://github.com/kilobyte/compsize/issues/34
Fixes: a48b73eca4 ("btrfs: fix potential deadlock in the search ioctl")
CC: stable@vger.kernel.org # 4.4+
Tested-by: A L <mail@lechevalier.se>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-14 17:27:16 +02:00
Linus Torvalds
edf6b0e1e4 for-5.9-rc4-tag
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Merge tag 'for-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more fixes:

   - regression fix for a crash after failed snapshot creation

   - one more lockep fix: use nofs allocation when allocating missing
     device

   - fix reloc tree leak on degraded mount

   - make some extent buffer alignment checks less strict to mount
     filesystems created by btrfs-convert"

* tag 'for-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix NULL pointer dereference after failure to create snapshot
  btrfs: free data reloc tree on failed mount
  btrfs: require only sector size alignment for parent eb bytenr
  btrfs: fix lockdep splat in add_missing_dev
2020-09-12 12:28:39 -07:00
Filipe Manana
2d892ccdc1 btrfs: fix NULL pointer dereference after failure to create snapshot
When trying to get a new fs root for a snapshot during the transaction
at transaction.c:create_pending_snapshot(), if btrfs_get_new_fs_root()
fails we leave "pending->snap" pointing to an error pointer, and then
later at ioctl.c:create_snapshot() we dereference that pointer, resulting
in a crash:

  [12264.614689] BUG: kernel NULL pointer dereference, address: 00000000000007c4
  [12264.615650] #PF: supervisor write access in kernel mode
  [12264.616487] #PF: error_code(0x0002) - not-present page
  [12264.617436] PGD 0 P4D 0
  [12264.618328] Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
  [12264.619150] CPU: 0 PID: 2310635 Comm: fsstress Tainted: G        W         5.9.0-rc3-btrfs-next-67 #1
  [12264.619960] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  [12264.621769] RIP: 0010:btrfs_mksubvol+0x438/0x4a0 [btrfs]
  [12264.622528] Code: bc ef ff ff (...)
  [12264.624092] RSP: 0018:ffffaa6fc7277cd8 EFLAGS: 00010282
  [12264.624669] RAX: 00000000fffffff4 RBX: ffff9d3e8f151a60 RCX: 0000000000000000
  [12264.625249] RDX: 0000000000000001 RSI: ffffffff9d56c9be RDI: fffffffffffffff4
  [12264.625830] RBP: ffff9d3e8f151b48 R08: 0000000000000000 R09: 0000000000000000
  [12264.626413] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffff4
  [12264.626994] R13: ffff9d3ede380538 R14: ffff9d3ede380500 R15: ffff9d3f61b2eeb8
  [12264.627582] FS:  00007f140d5d8200(0000) GS:ffff9d3fb5e00000(0000) knlGS:0000000000000000
  [12264.628176] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [12264.628773] CR2: 00000000000007c4 CR3: 000000020f8e8004 CR4: 00000000003706f0
  [12264.629379] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [12264.629994] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [12264.630594] Call Trace:
  [12264.631227]  btrfs_mksnapshot+0x7b/0xb0 [btrfs]
  [12264.631840]  __btrfs_ioctl_snap_create+0x16f/0x1a0 [btrfs]
  [12264.632458]  btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs]
  [12264.633078]  btrfs_ioctl+0x1864/0x3130 [btrfs]
  [12264.633689]  ? do_sys_openat2+0x1a7/0x2d0
  [12264.634295]  ? kmem_cache_free+0x147/0x3a0
  [12264.634899]  ? __x64_sys_ioctl+0x83/0xb0
  [12264.635488]  __x64_sys_ioctl+0x83/0xb0
  [12264.636058]  do_syscall_64+0x33/0x80
  [12264.636616]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

  (gdb) list *(btrfs_mksubvol+0x438)
  0x7c7b8 is in btrfs_mksubvol (fs/btrfs/ioctl.c:858).
  853		ret = 0;
  854		pending_snapshot->anon_dev = 0;
  855	fail:
  856		/* Prevent double freeing of anon_dev */
  857		if (ret && pending_snapshot->snap)
  858			pending_snapshot->snap->anon_dev = 0;
  859		btrfs_put_root(pending_snapshot->snap);
  860		btrfs_subvolume_release_metadata(root, &pending_snapshot->block_rsv);
  861	free_pending:
  862		if (pending_snapshot->anon_dev)

So fix this by setting "pending->snap" to NULL if we get an error from the
call to btrfs_get_new_fs_root() at transaction.c:create_pending_snapshot().

Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 21:18:35 +02:00
Josef Bacik
9e3aa80544 btrfs: free data reloc tree on failed mount
While testing a weird problem with -o degraded, I noticed I was getting
leaked root errors

  BTRFS warning (device loop0): writable mount is not allowed due to too many missing devices
  BTRFS error (device loop0): open_ctree failed
  BTRFS error (device loop0): leaked root -9-0 refcount 1

This is the DATA_RELOC root, which gets read before the other fs roots,
but is included in the fs roots radix tree.  Handle this by adding a
btrfs_drop_and_free_fs_root() on the data reloc root if it exists.  This
is ok to do here if we fail further up because we will only drop the ref
if we delete the root from the radix tree, and all other cleanup won't
be duplicated.

CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:51:15 +02:00
Qu Wenruo
ea57788eb7 btrfs: require only sector size alignment for parent eb bytenr
[BUG]
A completely sane converted fs will cause kernel warning at balance
time:

  [ 1557.188633] BTRFS info (device sda7): relocating block group 8162107392 flags data
  [ 1563.358078] BTRFS info (device sda7): found 11722 extents
  [ 1563.358277] BTRFS info (device sda7): leaf 7989321728 gen 95 total ptrs 213 free space 3458 owner 2
  [ 1563.358280] 	item 0 key (7984947200 169 0) itemoff 16250 itemsize 33
  [ 1563.358281] 		extent refs 1 gen 90 flags 2
  [ 1563.358282] 		ref#0: tree block backref root 4
  [ 1563.358285] 	item 1 key (7985602560 169 0) itemoff 16217 itemsize 33
  [ 1563.358286] 		extent refs 1 gen 93 flags 258
  [ 1563.358287] 		ref#0: shared block backref parent 7985602560
  [ 1563.358288] 			(parent 7985602560 is NOT ALIGNED to nodesize 16384)
  [ 1563.358290] 	item 2 key (7985635328 169 0) itemoff 16184 itemsize 33
  ...
  [ 1563.358995] BTRFS error (device sda7): eb 7989321728 invalid extent inline ref type 182
  [ 1563.358996] ------------[ cut here ]------------
  [ 1563.359005] WARNING: CPU: 14 PID: 2930 at 0xffffffff9f231766

Then with transaction abort, and obviously failed to balance the fs.

[CAUSE]
That mentioned inline ref type 182 is completely sane, it's
BTRFS_SHARED_BLOCK_REF_KEY, it's some extra check making kernel to
believe it's invalid.

Commit 64ecdb647d ("Btrfs: add one more sanity check for shared ref
type") introduced extra checks for backref type.

One of the requirement is, parent bytenr must be aligned to node size,
which is not correct.

One example is like this:

0	1G  1G+4K		2G 2G+4K
	|   |///////////////////|//|  <- A chunk starts at 1G+4K
            |   |	<- A tree block get reserved at bytenr 1G+4K

Then we have a valid tree block at bytenr 1G+4K, but not aligned to
nodesize (16K).

Such chunk is not ideal, but current kernel can handle it pretty well.
We may warn about such tree block in the future, but should not reject
them.

[FIX]
Change the alignment requirement from node size alignment to sector size
alignment.

Also, to make our lives a little easier, also output @iref when
btrfs_get_extent_inline_ref_type() failed, so we can locate the item
easier.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205475
Fixes: 64ecdb647d ("Btrfs: add one more sanity check for shared ref type")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ update comments and messages ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:51:05 +02:00
Josef Bacik
fccc0007b8 btrfs: fix lockdep splat in add_missing_dev
Nikolay reported a lockdep splat in generic/476 that I could reproduce
with btrfs/187.

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0-rc2+ #1 Tainted: G        W
  ------------------------------------------------------
  kswapd0/100 is trying to acquire lock:
  ffff9e8ef38b6268 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330

  but task is already holding lock:
  ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (fs_reclaim){+.+.}-{0:0}:
	 fs_reclaim_acquire+0x65/0x80
	 slab_pre_alloc_hook.constprop.0+0x20/0x200
	 kmem_cache_alloc_trace+0x3a/0x1a0
	 btrfs_alloc_device+0x43/0x210
	 add_missing_dev+0x20/0x90
	 read_one_chunk+0x301/0x430
	 btrfs_read_sys_array+0x17b/0x1b0
	 open_ctree+0xa62/0x1896
	 btrfs_mount_root.cold+0x12/0xea
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 vfs_kern_mount.part.0+0x71/0xb0
	 btrfs_mount+0x10d/0x379
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 path_mount+0x434/0xc00
	 __x64_sys_mount+0xe3/0x120
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7e0
	 btrfs_chunk_alloc+0x125/0x3a0
	 find_free_extent+0xdf6/0x1210
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb0/0x310
	 alloc_tree_block_no_bg_flush+0x4a/0x60
	 __btrfs_cow_block+0x11a/0x530
	 btrfs_cow_block+0x104/0x220
	 btrfs_search_slot+0x52e/0x9d0
	 btrfs_lookup_inode+0x2a/0x8f
	 __btrfs_update_delayed_inode+0x80/0x240
	 btrfs_commit_inode_delayed_inode+0x119/0x120
	 btrfs_evict_inode+0x357/0x500
	 evict+0xcf/0x1f0
	 vfs_rmdir.part.0+0x149/0x160
	 do_rmdir+0x136/0x1a0
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
	 __lock_acquire+0x1184/0x1fa0
	 lock_acquire+0xa4/0x3d0
	 __mutex_lock+0x7e/0x7e0
	 __btrfs_release_delayed_node.part.0+0x3f/0x330
	 btrfs_evict_inode+0x24c/0x500
	 evict+0xcf/0x1f0
	 dispose_list+0x48/0x70
	 prune_icache_sb+0x44/0x50
	 super_cache_scan+0x161/0x1e0
	 do_shrink_slab+0x178/0x3c0
	 shrink_slab+0x17c/0x290
	 shrink_node+0x2b2/0x6d0
	 balance_pgdat+0x30a/0x670
	 kswapd+0x213/0x4c0
	 kthread+0x138/0x160
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(fs_reclaim);
				 lock(&fs_info->chunk_mutex);
				 lock(fs_reclaim);
    lock(&delayed_node->mutex);

   *** DEADLOCK ***

  3 locks held by kswapd0/100:
   #0: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffffa9d65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290
   #2: ffff9e8e9da260e0 (&type->s_umount_key#48){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0

  stack backtrace:
  CPU: 1 PID: 100 Comm: kswapd0 Tainted: G        W         5.9.0-rc2+ #1
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x92/0xc8
   check_noncircular+0x12d/0x150
   __lock_acquire+0x1184/0x1fa0
   lock_acquire+0xa4/0x3d0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   __mutex_lock+0x7e/0x7e0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? lock_acquire+0xa4/0x3d0
   ? btrfs_evict_inode+0x11e/0x500
   ? find_held_lock+0x2b/0x80
   __btrfs_release_delayed_node.part.0+0x3f/0x330
   btrfs_evict_inode+0x24c/0x500
   evict+0xcf/0x1f0
   dispose_list+0x48/0x70
   prune_icache_sb+0x44/0x50
   super_cache_scan+0x161/0x1e0
   do_shrink_slab+0x178/0x3c0
   shrink_slab+0x17c/0x290
   shrink_node+0x2b2/0x6d0
   balance_pgdat+0x30a/0x670
   kswapd+0x213/0x4c0
   ? _raw_spin_unlock_irqrestore+0x46/0x60
   ? add_wait_queue_exclusive+0x70/0x70
   ? balance_pgdat+0x670/0x670
   kthread+0x138/0x160
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30

This is because we are holding the chunk_mutex when we call
btrfs_alloc_device, which does a GFP_KERNEL allocation.  We don't want
to switch that to a GFP_NOFS lock because this is the only place where
it matters.  So instead use memalloc_nofs_save() around the allocation
in order to avoid the lockdep splat.

Reported-by: Nikolay Borisov <nborisov@suse.com>
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:50:57 +02:00
Linus Torvalds
dcdfd9cc28 for-5.9-rc3-tag
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Merge tag 'for-5.9-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two small fixes and a bunch of lockdep fixes for warnings that show up
  with an upcoming tree locking update but are valid with current locks
  as well"

* tag 'for-5.9-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: tree-checker: fix the error message for transid error
  btrfs: set the lockdep class for log tree extent buffers
  btrfs: set the correct lockdep class for new nodes
  btrfs: allocate scrub workqueues outside of locks
  btrfs: fix potential deadlock in the search ioctl
  btrfs: drop path before adding new uuid tree entry
  btrfs: block-group: fix free-space bitmap threshold
2020-09-01 18:36:45 -07:00
Qu Wenruo
f96d6960ab btrfs: tree-checker: fix the error message for transid error
The error message for inode transid is the same as for inode generation,
which makes us unable to detect the real problem.

Reported-by: Tyler Richmond <t.d.richmond@gmail.com>
Fixes: 496245cac5 ("btrfs: tree-checker: Verify inode item")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:16:05 +02:00
Josef Bacik
d3beaa253f btrfs: set the lockdep class for log tree extent buffers
These are special extent buffers that get rewound in order to lookup
the state of the tree at a specific point in time.  As such they do not
go through the normal initialization paths that set their lockdep class,
so handle them appropriately when they are created and before they are
locked.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:13:23 +02:00
Josef Bacik
ad24466588 btrfs: set the correct lockdep class for new nodes
When flipping over to the rw_semaphore I noticed I'd get a lockdep splat
in replace_path(), which is weird because we're swapping the reloc root
with the actual target root.  Turns out this is because we're using the
root->root_key.objectid as the root id for the newly allocated tree
block when setting the lockdep class, however we need to be using the
actual owner of this new block, which is saved in owner.

The affected path is through btrfs_copy_root as all other callers of
btrfs_alloc_tree_block (which calls init_new_buffer) have root_objectid
== root->root_key.objectid .

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:08:52 +02:00
Josef Bacik
e89c4a9c8e btrfs: allocate scrub workqueues outside of locks
I got the following lockdep splat while testing:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00172-g021118712e59 #932 Not tainted
  ------------------------------------------------------
  btrfs/229626 is trying to acquire lock:
  ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450

  but task is already holding lock:
  ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_scrub_dev+0x11c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_run_dev_stats+0x49/0x480
	 commit_cowonly_roots+0xb5/0x2a0
	 btrfs_commit_transaction+0x516/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_commit_transaction+0x4bb/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_record_root_in_trans+0x43/0x70
	 start_transaction+0xd1/0x5d0
	 btrfs_dirty_inode+0x42/0xd0
	 touch_atime+0xa1/0xd0
	 btrfs_file_mmap+0x3f/0x60
	 mmap_region+0x3a4/0x640
	 do_mmap+0x376/0x580
	 vm_mmap_pgoff+0xd5/0x120
	 ksys_mmap_pgoff+0x193/0x230
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #3 (&mm->mmap_lock#2){++++}-{3:3}:
	 __might_fault+0x68/0x90
	 _copy_to_user+0x1e/0x80
	 perf_read+0x141/0x2c0
	 vfs_read+0xad/0x1b0
	 ksys_read+0x5f/0xe0
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (&cpuctx_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x88/0x150
	 perf_event_init+0x1db/0x20b
	 start_kernel+0x3ae/0x53c
	 secondary_startup_64+0xa4/0xb0

  -> #1 (pmus_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x4f/0x150
	 cpuhp_invoke_callback+0xb1/0x900
	 _cpu_up.constprop.26+0x9f/0x130
	 cpu_up+0x7b/0xc0
	 bringup_nonboot_cpus+0x4f/0x60
	 smp_init+0x26/0x71
	 kernel_init_freeable+0x110/0x258
	 kernel_init+0xa/0x103
	 ret_from_fork+0x1f/0x30

  -> #0 (cpu_hotplug_lock){++++}-{0:0}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 cpus_read_lock+0x39/0xb0
	 alloc_workqueue+0x378/0x450
	 __btrfs_alloc_workqueue+0x15d/0x200
	 btrfs_alloc_workqueue+0x51/0x160
	 scrub_workers_get+0x5a/0x170
	 btrfs_scrub_dev+0x18c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->scrub_lock);
				 lock(&fs_devs->device_list_mutex);
				 lock(&fs_info->scrub_lock);
    lock(cpu_hotplug_lock);

   *** DEADLOCK ***

  2 locks held by btrfs/229626:
   #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630
   #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  stack backtrace:
  CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? alloc_workqueue+0x378/0x450
   cpus_read_lock+0x39/0xb0
   ? alloc_workqueue+0x378/0x450
   alloc_workqueue+0x378/0x450
   ? rcu_read_lock_sched_held+0x52/0x80
   __btrfs_alloc_workqueue+0x15d/0x200
   btrfs_alloc_workqueue+0x51/0x160
   scrub_workers_get+0x5a/0x170
   btrfs_scrub_dev+0x18c/0x630
   ? start_transaction+0xd1/0x5d0
   btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
   btrfs_ioctl+0x2799/0x30a0
   ? do_sigaction+0x102/0x250
   ? lockdep_hardirqs_on_prepare+0xca/0x160
   ? _raw_spin_unlock_irq+0x24/0x30
   ? trace_hardirqs_on+0x1c/0xe0
   ? _raw_spin_unlock_irq+0x24/0x30
   ? do_sigaction+0x102/0x250
   ? ksys_ioctl+0x83/0xc0
   ksys_ioctl+0x83/0xc0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x50/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This happens because we're allocating the scrub workqueues under the
scrub and device list mutex, which brings in a whole host of other
dependencies.

Because the work queue allocation is done with GFP_KERNEL, it can
trigger reclaim, which can lead to a transaction commit, which in turns
needs the device_list_mutex, it can lead to a deadlock. A different
problem for which this fix is a solution.

Fix this by moving the actual allocation outside of the
scrub lock, and then only take the lock once we're ready to actually
assign them to the fs_info.  We'll now have to cleanup the workqueues in
a few more places, so I've added a helper to do the refcount dance to
safely free the workqueues.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:06:02 +02:00
Josef Bacik
a48b73eca4 btrfs: fix potential deadlock in the search ioctl
With the conversion of the tree locks to rwsem I got the following
lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted
  ------------------------------------------------------
  compsize/11122 is trying to acquire lock:
  ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90

  but task is already holding lock:
  ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (btrfs-fs-00){++++}-{3:3}:
	 down_write_nested+0x3b/0x70
	 __btrfs_tree_lock+0x24/0x120
	 btrfs_search_slot+0x756/0x990
	 btrfs_lookup_inode+0x3a/0xb4
	 __btrfs_update_delayed_inode+0x93/0x270
	 btrfs_async_run_delayed_root+0x168/0x230
	 btrfs_work_helper+0xd4/0x570
	 process_one_work+0x2ad/0x5f0
	 worker_thread+0x3a/0x3d0
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  -> #1 (&delayed_node->mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_delayed_update_inode+0x50/0x440
	 btrfs_update_inode+0x8a/0xf0
	 btrfs_dirty_inode+0x5b/0xd0
	 touch_atime+0xa1/0xd0
	 btrfs_file_mmap+0x3f/0x60
	 mmap_region+0x3a4/0x640
	 do_mmap+0x376/0x580
	 vm_mmap_pgoff+0xd5/0x120
	 ksys_mmap_pgoff+0x193/0x230
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&mm->mmap_lock#2){++++}-{3:3}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 __might_fault+0x68/0x90
	 _copy_to_user+0x1e/0x80
	 copy_to_sk.isra.32+0x121/0x300
	 search_ioctl+0x106/0x200
	 btrfs_ioctl_tree_search_v2+0x7b/0xf0
	 btrfs_ioctl+0x106f/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-fs-00);
				 lock(&delayed_node->mutex);
				 lock(btrfs-fs-00);
    lock(&mm->mmap_lock#2);

   *** DEADLOCK ***

  1 lock held by compsize/11122:
   #0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  stack backtrace:
  CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? __might_fault+0x3e/0x90
   ? find_held_lock+0x72/0x90
   __might_fault+0x68/0x90
   ? __might_fault+0x3e/0x90
   _copy_to_user+0x1e/0x80
   copy_to_sk.isra.32+0x121/0x300
   ? btrfs_search_forward+0x2a6/0x360
   search_ioctl+0x106/0x200
   btrfs_ioctl_tree_search_v2+0x7b/0xf0
   btrfs_ioctl+0x106f/0x30a0
   ? __do_sys_newfstat+0x5a/0x70
   ? ksys_ioctl+0x83/0xc0
   ksys_ioctl+0x83/0xc0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x50/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The problem is we're doing a copy_to_user() while holding tree locks,
which can deadlock if we have to do a page fault for the copy_to_user().
This exists even without my locking changes, so it needs to be fixed.
Rework the search ioctl to do the pre-fault and then
copy_to_user_nofault for the copying.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:56:27 +02:00
Josef Bacik
9771a5cf93 btrfs: drop path before adding new uuid tree entry
With the conversion of the tree locks to rwsem I got the following
lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Not tainted
  ------------------------------------------------------
  btrfs-uuid/7955 is trying to acquire lock:
  ffff88bfbafec0f8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  but task is already holding lock:
  ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (btrfs-uuid-00){++++}-{3:3}:
	 down_read_nested+0x3e/0x140
	 __btrfs_tree_read_lock+0x39/0x180
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x4bd/0x990
	 btrfs_uuid_tree_add+0x89/0x2d0
	 btrfs_uuid_scan_kthread+0x330/0x390
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  -> #0 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 down_read_nested+0x3e/0x140
	 __btrfs_tree_read_lock+0x39/0x180
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x4bd/0x990
	 btrfs_find_root+0x45/0x1b0
	 btrfs_read_tree_root+0x61/0x100
	 btrfs_get_root_ref.part.50+0x143/0x630
	 btrfs_uuid_tree_iterate+0x207/0x314
	 btrfs_uuid_rescan_kthread+0x12/0x50
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-uuid-00);
				 lock(btrfs-root-00);
				 lock(btrfs-uuid-00);
    lock(btrfs-root-00);

   *** DEADLOCK ***

  1 lock held by btrfs-uuid/7955:
   #0: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  stack backtrace:
  CPU: 73 PID: 7955 Comm: btrfs-uuid Kdump: loaded Not tainted 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? __btrfs_tree_read_lock+0x39/0x180
   ? btrfs_root_node+0x1c/0x1d0
   down_read_nested+0x3e/0x140
   ? __btrfs_tree_read_lock+0x39/0x180
   __btrfs_tree_read_lock+0x39/0x180
   __btrfs_read_lock_root_node+0x3a/0x50
   btrfs_search_slot+0x4bd/0x990
   btrfs_find_root+0x45/0x1b0
   btrfs_read_tree_root+0x61/0x100
   btrfs_get_root_ref.part.50+0x143/0x630
   btrfs_uuid_tree_iterate+0x207/0x314
   ? btree_readpage+0x20/0x20
   btrfs_uuid_rescan_kthread+0x12/0x50
   kthread+0x133/0x150
   ? kthread_create_on_node+0x60/0x60
   ret_from_fork+0x1f/0x30

This problem exists because we have two different rescan threads,
btrfs_uuid_scan_kthread which creates the uuid tree, and
btrfs_uuid_tree_iterate that goes through and updates or deletes any out
of date roots.  The problem is they both do things in different order.
btrfs_uuid_scan_kthread() reads the tree_root, and then inserts entries
into the uuid_root.  btrfs_uuid_tree_iterate() scans the uuid_root, but
then does a btrfs_get_fs_root() which can read from the tree_root.

It's actually easy enough to not be holding the path in
btrfs_uuid_scan_kthread() when we add a uuid entry, as we already drop
it further down and re-start the search when we loop.  So simply move
the path release before we add our entry to the uuid tree.

This also fixes a problem where we're holding a path open after we do
btrfs_end_transaction(), which has it's own problems.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:46:15 +02:00
Marcos Paulo de Souza
e3e39c72b9 btrfs: block-group: fix free-space bitmap threshold
[BUG]
After commit 9afc66498a ("btrfs: block-group: refactor how we read one
block group item"), cache->length is being assigned after calling
btrfs_create_block_group_cache. This causes a problem since
set_free_space_tree_thresholds calculates the free-space threshold to
decide if the free-space tree should convert from extents to bitmaps.

The current code calls set_free_space_tree_thresholds with cache->length
being 0, which then makes cache->bitmap_high_thresh zero. This implies
the system will always use bitmap instead of extents, which is not
desired if the block group is not fragmented.

This behavior can be seen by a test that expects to repair systems
with FREE_SPACE_EXTENT and FREE_SPACE_BITMAP, but the current code only
created FREE_SPACE_BITMAP.

[FIX]
Call set_free_space_tree_thresholds after setting cache->length. There
is now a WARN_ON in set_free_space_tree_thresholds to help preventing
the same mistake to happen again in the future.

Link: https://github.com/kdave/btrfs-progs/issues/251
Fixes: 9afc66498a ("btrfs: block-group: refactor how we read one block group item")
CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:37:54 +02:00
Linus Torvalds
9907ab3714 for-5.9-rc2-tag
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Merge tag 'for-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix swapfile activation on subvolumes with deleted snapshots

 - error value mixup when removing directory entries from tree log

 - fix lzo compression level reset after previous level setting

 - fix space cache memory leak after transaction abort

 - fix const function attribute

 - more error handling improvements

* tag 'for-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: detect nocow for swap after snapshot delete
  btrfs: check the right error variable in btrfs_del_dir_entries_in_log
  btrfs: fix space cache memory leak after transaction abort
  btrfs: use the correct const function attribute for btrfs_get_num_csums
  btrfs: reset compression level for lzo on remount
  btrfs: handle errors from async submission
2020-08-24 12:01:20 -07:00
Boris Burkov
a84d5d429f btrfs: detect nocow for swap after snapshot delete
can_nocow_extent and btrfs_cross_ref_exist both rely on a heuristic for
detecting a must cow condition which is not exactly accurate, but saves
unnecessary tree traversal. The incorrect assumption is that if the
extent was created in a generation smaller than the last snapshot
generation, it must be referenced by that snapshot. That is true, except
the snapshot could have since been deleted, without affecting the last
snapshot generation.

The original patch claimed a performance win from this check, but it
also leads to a bug where you are unable to use a swapfile if you ever
snapshotted the subvolume it's in. Make the check slower and more strict
for the swapon case, without modifying the general cow checks as a
compromise. Turning swap on does not seem to be a particularly
performance sensitive operation, so incurring a possibly unnecessary
btrfs_search_slot seems worthwhile for the added usability.

Note: Until the snapshot is competely cleaned after deletion,
check_committed_refs will still cause the logic to think that cow is
necessary, so the user must until 'btrfs subvolu sync' finished before
activating the swapfile swapon.

CC: stable@vger.kernel.org # 5.4+
Suggested-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-21 12:21:23 +02:00
Josef Bacik
fb2fecbad5 btrfs: check the right error variable in btrfs_del_dir_entries_in_log
With my new locking code dbench is so much faster that I tripped over a
transaction abort from ENOSPC.  This turned out to be because
btrfs_del_dir_entries_in_log was checking for ret == -ENOSPC, but this
function sets err on error, and returns err.  So instead of properly
marking the inode as needing a full commit, we were returning -ENOSPC
and aborting in __btrfs_unlink_inode.  Fix this by checking the proper
variable so that we return the correct thing in the case of ENOSPC.

The ENOENT needs to be checked, because btrfs_lookup_dir_item_index()
can return -ENOENT if the dir item isn't in the tree log (which would
happen if we hadn't fsync'ed this guy).  We actually handle that case in
__btrfs_unlink_inode, so it's an expected error to get back.

Fixes: 4a500fd178 ("Btrfs: Metadata ENOSPC handling for tree log")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note and comment about ENOENT ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-21 12:20:01 +02:00
Filipe Manana
bbc37d6e47 btrfs: fix space cache memory leak after transaction abort
If a transaction aborts it can cause a memory leak of the pages array of
a block group's io_ctl structure. The following steps explain how that can
happen:

1) Transaction N is committing, currently in state TRANS_STATE_UNBLOCKED
   and it's about to start writing out dirty extent buffers;

2) Transaction N + 1 already started and another task, task A, just called
   btrfs_commit_transaction() on it;

3) Block group B was dirtied (extents allocated from it) by transaction
   N + 1, so when task A calls btrfs_start_dirty_block_groups(), at the
   very beginning of the transaction commit, it starts writeback for the
   block group's space cache by calling btrfs_write_out_cache(), which
   allocates the pages array for the block group's io_ctl with a call to
   io_ctl_init(). Block group A is added to the io_list of transaction
   N + 1 by btrfs_start_dirty_block_groups();

4) While transaction N's commit is writing out the extent buffers, it gets
   an IO error and aborts transaction N, also setting the file system to
   RO mode;

5) Task A has already returned from btrfs_start_dirty_block_groups(), is at
   btrfs_commit_transaction() and has set transaction N + 1 state to
   TRANS_STATE_COMMIT_START. Immediately after that it checks that the
   filesystem was turned to RO mode, due to transaction N's abort, and
   jumps to the "cleanup_transaction" label. After that we end up at
   btrfs_cleanup_one_transaction() which calls btrfs_cleanup_dirty_bgs().
   That helper finds block group B in the transaction's io_list but it
   never releases the pages array of the block group's io_ctl, resulting in
   a memory leak.

In fact at the point when we are at btrfs_cleanup_dirty_bgs(), the pages
array points to pages that were already released by us at
__btrfs_write_out_cache() through the call to io_ctl_drop_pages(). We end
up freeing the pages array only after waiting for the ordered extent to
complete through btrfs_wait_cache_io(), which calls io_ctl_free() to do
that. But in the transaction abort case we don't wait for the space cache's
ordered extent to complete through a call to btrfs_wait_cache_io(), so
that's why we end up with a memory leak - we wait for the ordered extent
to complete indirectly by shutting down the work queues and waiting for
any jobs in them to complete before returning from close_ctree().

We can solve the leak simply by freeing the pages array right after
releasing the pages (with the call to io_ctl_drop_pages()) at
__btrfs_write_out_cache(), since we will never use it anymore after that
and the pages array points to already released pages at that point, which
is currently not a problem since no one will use it after that, but not a
good practice anyway since it can easily lead to use-after-free issues.

So fix this by freeing the pages array right after releasing the pages at
__btrfs_write_out_cache().

This issue can often be reproduced with test case generic/475 from fstests
and kmemleak can detect it and reports it with the following trace:

unreferenced object 0xffff9bbf009fa600 (size 512):
  comm "fsstress", pid 38807, jiffies 4298504428 (age 22.028s)
  hex dump (first 32 bytes):
    00 a0 7c 4d 3d ed ff ff 40 a0 7c 4d 3d ed ff ff  ..|M=...@.|M=...
    80 a0 7c 4d 3d ed ff ff c0 a0 7c 4d 3d ed ff ff  ..|M=.....|M=...
  backtrace:
    [<00000000f4b5cfe2>] __kmalloc+0x1a8/0x3e0
    [<0000000028665e7f>] io_ctl_init+0xa7/0x120 [btrfs]
    [<00000000a1f95b2d>] __btrfs_write_out_cache+0x86/0x4a0 [btrfs]
    [<00000000207ea1b0>] btrfs_write_out_cache+0x7f/0xf0 [btrfs]
    [<00000000af21f534>] btrfs_start_dirty_block_groups+0x27b/0x580 [btrfs]
    [<00000000c3c23d44>] btrfs_commit_transaction+0xa6f/0xe70 [btrfs]
    [<000000009588930c>] create_subvol+0x581/0x9a0 [btrfs]
    [<000000009ef2fd7f>] btrfs_mksubvol+0x3fb/0x4a0 [btrfs]
    [<00000000474e5187>] __btrfs_ioctl_snap_create+0x119/0x1a0 [btrfs]
    [<00000000708ee349>] btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs]
    [<00000000ea60106f>] btrfs_ioctl+0x12c/0x3130 [btrfs]
    [<000000005c923d6d>] __x64_sys_ioctl+0x83/0xb0
    [<0000000043ace2c9>] do_syscall_64+0x33/0x80
    [<00000000904efbce>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:46 +02:00
David Sterba
604997b4a3 btrfs: use the correct const function attribute for btrfs_get_num_csums
The build robot reports

compiler: h8300-linux-gcc (GCC) 9.3.0
   In file included from fs/btrfs/tests/extent-map-tests.c:8:
>> fs/btrfs/tests/../ctree.h:2166:8: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
    2166 | size_t __const btrfs_get_num_csums(void);
         |        ^~~~~~~

The function attribute for const does not follow the expected scheme and
in this case is confused with a const type qualifier.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:21 +02:00
Marcos Paulo de Souza
282dd7d771 btrfs: reset compression level for lzo on remount
Currently a user can set mount "-o compress" which will set the
compression algorithm to zlib, and use the default compress level for
zlib (3):

  relatime,compress=zlib:3,space_cache

If the user remounts the fs using "-o compress=lzo", then the old
compress_level is used:

  relatime,compress=lzo:3,space_cache

But lzo does not expose any tunable compression level. The same happens
if we set any compress argument with different level, also with zstd.

Fix this by resetting the compress_level when compress=lzo is
specified.  With the fix applied, lzo is shown without compress level:

  relatime,compress=lzo,space_cache

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:12 +02:00
Johannes Thumshirn
c965d6402f btrfs: handle errors from async submission
Btrfs' async submit mechanism is able to handle errors in the submission
path and the meta-data async submit function correctly passes the error
code to the caller.

In btrfs_submit_bio_start() and btrfs_submit_bio_start_direct_io() we're
not handling the errors returned by btrfs_csum_one_bio() correctly though
and simply call BUG_ON(). This is unnecessary as the caller of these two
functions - run_one_async_start - correctly checks for the return values
and sets the status of the async_submit_bio. The actual bio submission
will be handled later on by run_one_async_done only if
async_submit_bio::status is 0, so the data won't be written if we
encountered an error in the checksum process.

Simply return the error from btrfs_csum_one_bio() to the async submitters,
like it's done in btree_submit_bio_start().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:26:14 +02:00
Linus Torvalds
23c2c8c6fa for-5.9-tag
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Merge tag 'for-5.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull more btrfs updates from David Sterba:
 "One minor update, the rest are fixes that have arrived a bit late for
  the first batch. There are also some recent fixes for bugs that were
  discovered during the merge window and pop up during testing.

  User visible change:

   - show correct subvolume path in /proc/mounts for bind mounts

  Fixes:

   - fix compression messages when remounting with different level or
     compression algorithm

   - tree-log: fix some memory leaks on error handling paths

   - restore I_VERSION on remount

   - fix return values and error code mixups

   - fix umount crash with quotas enabled when removing sysfs files

   - fix trim range on a shrunk device"

* tag 'for-5.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: trim: fix underflow in trim length to prevent access beyond device boundary
  btrfs: fix return value mixup in btrfs_get_extent
  btrfs: sysfs: fix NULL pointer dereference at btrfs_sysfs_del_qgroups()
  btrfs: check correct variable after allocation in btrfs_backref_iter_alloc
  btrfs: make sure SB_I_VERSION doesn't get unset by remount
  btrfs: fix memory leaks after failure to lookup checksums during inode logging
  btrfs: don't show full path of bind mounts in subvol=
  btrfs: fix messages after changing compression level by remount
  btrfs: only search for left_info if there is no right_info in try_merge_free_space
  btrfs: inode: fix NULL pointer dereference if inode doesn't need compression
2020-08-13 12:26:18 -07:00
Qu Wenruo
c57dd1f2f6 btrfs: trim: fix underflow in trim length to prevent access beyond device boundary
[BUG]
The following script can lead to tons of beyond device boundary access:

  mkfs.btrfs -f $dev -b 10G
  mount $dev $mnt
  trimfs $mnt
  btrfs filesystem resize 1:-1G $mnt
  trimfs $mnt

[CAUSE]
Since commit 929be17a9b ("btrfs: Switch btrfs_trim_free_extents to
find_first_clear_extent_bit"), we try to avoid trimming ranges that's
already trimmed.

So we check device->alloc_state by finding the first range which doesn't
have CHUNK_TRIMMED and CHUNK_ALLOCATED not set.

But if we shrunk the device, that bits are not cleared, thus we could
easily got a range starts beyond the shrunk device size.

This results the returned @start and @end are all beyond device size,
then we call "end = min(end, device->total_bytes -1);" making @end
smaller than device size.

Then finally we goes "len = end - start + 1", totally underflow the
result, and lead to the beyond-device-boundary access.

[FIX]
This patch will fix the problem in two ways:

- Clear CHUNK_TRIMMED | CHUNK_ALLOCATED bits when shrinking device
  This is the root fix

- Add extra safety check when trimming free device extents
  We check and warn if the returned range is already beyond current
  device.

Link: https://github.com/kdave/btrfs-progs/issues/282
Fixes: 929be17a9b ("btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-12 10:15:58 +02:00
Pavel Machek
881a3a11c2 btrfs: fix return value mixup in btrfs_get_extent
btrfs_get_extent() sets variable ret, but out: error path expect error
to be in variable err so the error code is lost.

Fixes: 6bf9e4bd6a ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 12:30:17 +02:00
Qu Wenruo
62ab2cc04d btrfs: sysfs: fix NULL pointer dereference at btrfs_sysfs_del_qgroups()
[BUG]
Unmounting a btrfs filesystem with quota disabled will cause the
following NULL pointer dereference:

  BTRFS info (device dm-5): has skinny extents
  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  CPU: 7 PID: 637 Comm: umount Not tainted 5.8.0-rc7-next-20200731-custom #76
  RIP: 0010:kobject_del+0x6/0x20
  Call Trace:
   btrfs_sysfs_del_qgroups+0xac/0xf0 [btrfs]
   btrfs_free_qgroup_config+0x63/0x70 [btrfs]
   close_ctree+0x1f5/0x323 [btrfs]
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   exit_to_user_mode_prepare+0x18a/0x190
   syscall_exit_to_user_mode+0x4f/0x270
   do_syscall_64+0x45/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 37b7adca5c1d5c5d ]---

[CAUSE]
Commit 079ad2fb4b ("kobject: Avoid premature parent object freeing in
kobject_cleanup()") changed kobject_del() that it no longer accepts NULL
pointer.

Before that commit, kobject_del() and kobject_put() all accept NULL
pointers and just ignore such NULL pointers.

But that mentioned commit needs to access the parent node, killing the
old NULL pointer behavior.

Unfortunately btrfs is relying on that hidden feature thus we will
trigger such NULL pointer dereference.

[FIX]
Instead of just saving several lines, do proper fs_info->qgroups_kobj
check before calling kobject_del() and kobject_put().

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 19:51:08 +02:00
Boleyn Su
c15c2ec07a btrfs: check correct variable after allocation in btrfs_backref_iter_alloc
The `if (!ret)` check will always be false and it may result in
ret->path being dereferenced while it is a NULL pointer.

Fixes: a37f232b7b ("btrfs: backref: introduce the skeleton of btrfs_backref_iter")
CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boleyn Su <boleynsu@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 19:50:54 +02:00
Josef Bacik
faa008899a btrfs: make sure SB_I_VERSION doesn't get unset by remount
There's some inconsistency around SB_I_VERSION handling with mount and
remount.  Since we don't really want it to be off ever just work around
this by making sure we don't get the flag cleared on remount.

There's a tiny cpu cost of setting the bit, otherwise all changes to
i_version also change some of the times (ctime/mtime) so the inode needs
to be synced. We wouldn't save anything by disabling it.

Reported-by: Eric Sandeen <sandeen@redhat.com>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add perf impact analysis ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:35 +02:00
Filipe Manana
4f26433e9b btrfs: fix memory leaks after failure to lookup checksums during inode logging
While logging an inode, at copy_items(), if we fail to lookup the checksums
for an extent we release the destination path, free the ins_data array and
then return immediately. However a previous iteration of the for loop may
have added checksums to the ordered_sums list, in which case we leak the
memory used by them.

So fix this by making sure we iterate the ordered_sums list and free all
its checksums before returning.

Fixes: 3650860b90 ("Btrfs: remove almost all of the BUG()'s from tree-log.c")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:30 +02:00
Josef Bacik
3ef3959b29 btrfs: don't show full path of bind mounts in subvol=
Chris Murphy reported a problem where rpm ostree will bind mount a bunch
of things for whatever voodoo it's doing.  But when it does this
/proc/mounts shows something like

  /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0
  /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo/bar 0 0

Despite subvolid=256 being subvol=/foo.  This is because we're just
spitting out the dentry of the mount point, which in the case of bind
mounts is the source path for the mountpoint.  Instead we should spit
out the path to the actual subvol.  Fix this by looking up the name for
the subvolid we have mounted.  With this fix the same test looks like
this

  /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0
  /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo 0 0

Reported-by: Chris Murphy <chris@colorremedies.com>
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>
2020-08-10 18:58:26 +02:00
David Sterba
27942c9971 btrfs: fix messages after changing compression level by remount
Reported by Forza on IRC that remounting with compression options does
not reflect the change in level, or at least it does not appear to do so
according to the messages:

  mount -o compress=zstd:1 /dev/sda /mnt
  mount -o remount,compress=zstd:15 /mnt

does not print the change to the level to syslog:

  [   41.366060] BTRFS info (device vda): use zstd compression, level 1
  [   41.368254] BTRFS info (device vda): disk space caching is enabled
  [   41.390429] BTRFS info (device vda): disk space caching is enabled

What really happens is that the message is lost but the level is actualy
changed.

There's another weird output, if compression is reset to 'no':

  [   45.413776] BTRFS info (device vda): use no compression, level 4

To fix that, save the previous compression level and print the message
in that case too and use separate message for 'no' compression.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:16 +02:00
Josef Bacik
bf53d4687b btrfs: only search for left_info if there is no right_info in try_merge_free_space
In try_to_merge_free_space we attempt to find entries to the left and
right of the entry we are adding to see if they can be merged.  We
search for an entry past our current info (saved into right_info), and
then if right_info exists and it has a rb_prev() we save the rb_prev()
into left_info.

However there's a slight problem in the case that we have a right_info,
but no entry previous to that entry.  At that point we will search for
an entry just before the info we're attempting to insert.  This will
simply find right_info again, and assign it to left_info, making them
both the same pointer.

Now if right_info _can_ be merged with the range we're inserting, we'll
add it to the info and free right_info.  However further down we'll
access left_info, which was right_info, and thus get a use-after-free.

Fix this by only searching for the left entry if we don't find a right
entry at all.

The CVE referenced had a specially crafted file system that could
trigger this use-after-free. However with the tree checker improvements
we no longer trigger the conditions for the UAF.  But the original
conditions still apply, hence this fix.

Reference: CVE-2019-19448
Fixes: 9630308170 ("Btrfs: use hybrid extents+bitmap rb tree for free space")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:07 +02:00
Qu Wenruo
1e6e238c30 btrfs: inode: fix NULL pointer dereference if inode doesn't need compression
[BUG]
There is a bug report of NULL pointer dereference caused in
compress_file_extent():

  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Workqueue: btrfs-delalloc btrfs_delalloc_helper [btrfs]
  NIP [c008000006dd4d34] compress_file_range.constprop.41+0x75c/0x8a0 [btrfs]
  LR [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs]
  Call Trace:
  [c000000c69093b00] [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs] (unreliable)
  [c000000c69093bd0] [c008000006dd4ebc] async_cow_start+0x44/0xa0 [btrfs]
  [c000000c69093c10] [c008000006e14824] normal_work_helper+0xdc/0x598 [btrfs]
  [c000000c69093c80] [c0000000001608c0] process_one_work+0x2c0/0x5b0
  [c000000c69093d10] [c000000000160c38] worker_thread+0x88/0x660
  [c000000c69093db0] [c00000000016b55c] kthread+0x1ac/0x1c0
  [c000000c69093e20] [c00000000000b660] ret_from_kernel_thread+0x5c/0x7c
  ---[ end trace f16954aa20d822f6 ]---

[CAUSE]
For the following execution route of compress_file_range(), it's
possible to hit NULL pointer dereference:

 compress_file_extent()
 |- pages = NULL;
 |- start = async_chunk->start = 0;
 |- end = async_chunk = 4095;
 |- nr_pages = 1;
 |- inode_need_compress() == false; <<< Possible, see later explanation
 |  Now, we have nr_pages = 1, pages = NULL
 |- cont:
 |- 		ret = cow_file_range_inline();
 |- 		if (ret <= 0) {
 |-		for (i = 0; i < nr_pages; i++) {
 |-			WARN_ON(pages[i]->mapping);	<<< Crash

To enter above call execution branch, we need the following race:

    Thread 1 (chattr)     |            Thread 2 (writeback)
--------------------------+------------------------------
                          | btrfs_run_delalloc_range
                          | |- inode_need_compress = true
                          | |- cow_file_range_async()
btrfs_ioctl_set_flag()    |
|- binode_flags |=        |
   BTRFS_INODE_NOCOMPRESS |
                          | compress_file_range()
                          | |- inode_need_compress = false
                          | |- nr_page = 1 while pages = NULL
                          | |  Then hit the crash

[FIX]
This patch will fix it by checking @pages before doing accessing it.
This patch is only designed as a hot fix and easy to backport.

More elegant fix may make btrfs only check inode_need_compress() once to
avoid such race, but that would be another story.

Reported-by: Luciano Chavez <chavez@us.ibm.com>
Fixes: 4d3a800ebb ("btrfs: merge nr_pages input and output parameter in compress_pages")
CC: stable@vger.kernel.org # 4.14.x: cecc8d9038: btrfs: Move free_pages_out label in inline extent handling branch in compress_file_range
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:57:59 +02:00
Linus Torvalds
b79675e15a Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "No common topic whatsoever in those, sorry"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: define inode flags using bit numbers
  iov_iter: Move unnecessary inclusion of crypto/hash.h
  dlmfs: clean up dlmfs_file_{read,write}() a bit
2020-08-07 21:14:30 -07:00
Linus Torvalds
8f0cb6660a These are the latest RCU bits for v5.9:
- kfree_rcu updates
   - RCU tasks updates
   - Read-side scalability tests
   - SRCU updates
   - Torture-test updates
   - Documentation updates
   - Miscellaneous fixes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - kfree_rcu updates

 - RCU tasks updates

 - Read-side scalability tests

 - SRCU updates

 - Torture-test updates

 - Documentation updates

 - Miscellaneous fixes

* tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (109 commits)
  torture: Remove obsolete "cd $KVM"
  torture: Avoid duplicate specification of qemu command
  torture: Dump ftrace at shutdown only if requested
  torture: Add kvm-tranform.sh script for qemu-cmd files
  torture: Add more tracing crib notes to kvm.sh
  torture: Improve diagnostic for KCSAN-incapable compilers
  torture: Correctly summarize build-only runs
  torture: Pass --kmake-arg to all make invocations
  rcutorture: Check for unwatched readers
  torture: Abstract out console-log error detection
  torture: Add a stop-run capability
  torture: Create qemu-cmd in --buildonly runs
  rcu/rcutorture: Replace 0 with false
  torture: Add --allcpus argument to the kvm.sh script
  torture: Remove whitespace from identify_qemu_vcpus output
  rcutorture: NULL rcu_torture_current earlier in cleanup code
  rcutorture: Handle non-statistic bang-string error messages
  torture: Set configfile variable to current scenario
  rcutorture: Add races with task-exit processing
  locktorture: Use true and false to assign to bool variables
  ...
2020-08-03 14:31:33 -07:00
Linus Torvalds
cdc8fcb499 for-5.9/io_uring-20200802
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Merge tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Lots of cleanups in here, hardening the code and/or making it easier
  to read and fixing bugs, but a core feature/change too adding support
  for real async buffered reads. With the latter in place, we just need
  buffered write async support and we're done relying on kthreads for
  the fast path. In detail:

   - Cleanup how memory accounting is done on ring setup/free (Bijan)

   - sq array offset calculation fixup (Dmitry)

   - Consistently handle blocking off O_DIRECT submission path (me)

   - Support proper async buffered reads, instead of relying on kthread
     offload for that. This uses the page waitqueue to drive retries
     from task_work, like we handle poll based retry. (me)

   - IO completion optimizations (me)

   - Fix race with accounting and ring fd install (me)

   - Support EPOLLEXCLUSIVE (Jiufei)

   - Get rid of the io_kiocb unionizing, made possible by shrinking
     other bits (Pavel)

   - Completion side cleanups (Pavel)

   - Cleanup REQ_F_ flags handling, and kill off many of them (Pavel)

   - Request environment grabbing cleanups (Pavel)

   - File and socket read/write cleanups (Pavel)

   - Improve kiocb_set_rw_flags() (Pavel)

   - Tons of fixes and cleanups (Pavel)

   - IORING_SQ_NEED_WAKEUP clear fix (Xiaoguang)"

* tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block: (127 commits)
  io_uring: flip if handling after io_setup_async_rw
  fs: optimise kiocb_set_rw_flags()
  io_uring: don't touch 'ctx' after installing file descriptor
  io_uring: get rid of atomic FAA for cq_timeouts
  io_uring: consolidate *_check_overflow accounting
  io_uring: fix stalled deferred requests
  io_uring: fix racy overflow count reporting
  io_uring: deduplicate __io_complete_rw()
  io_uring: de-unionise io_kiocb
  io-wq: update hash bits
  io_uring: fix missing io_queue_linked_timeout()
  io_uring: mark ->work uninitialised after cleanup
  io_uring: deduplicate io_grab_files() calls
  io_uring: don't do opcode prep twice
  io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works
  io_uring: batch put_task_struct()
  tasks: add put_task_struct_many()
  io_uring: return locked and pinned page accounting
  io_uring: don't miscount pinned memory
  io_uring: don't open-code recv kbuf managment
  ...
2020-08-03 13:01:22 -07:00
Linus Torvalds
382625d0d4 for-5.9/block-20200802
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Merge tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block

Pull core block updates from Jens Axboe:
 "Good amount of cleanups and tech debt removals in here, and as a
  result, the diffstat shows a nice net reduction in code.

   - Softirq completion cleanups (Christoph)

   - Stop using ->queuedata (Christoph)

   - Cleanup bd claiming (Christoph)

   - Use check_events, moving away from the legacy media change
     (Christoph)

   - Use inode i_blkbits consistently (Christoph)

   - Remove old unused writeback congestion bits (Christoph)

   - Cleanup/unify submission path (Christoph)

   - Use bio_uninit consistently, instead of bio_disassociate_blkg
     (Christoph)

   - sbitmap cleared bits handling (John)

   - Request merging blktrace event addition (Jan)

   - sysfs add/remove race fixes (Luis)

   - blk-mq tag fixes/optimizations (Ming)

   - Duplicate words in comments (Randy)

   - Flush deferral cleanup (Yufen)

   - IO context locking/retry fixes (John)

   - struct_size() usage (Gustavo)

   - blk-iocost fixes (Chengming)

   - blk-cgroup IO stats fixes (Boris)

   - Various little fixes"

* tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block: (135 commits)
  block: blk-timeout: delete duplicated word
  block: blk-mq-sched: delete duplicated word
  block: blk-mq: delete duplicated word
  block: genhd: delete duplicated words
  block: elevator: delete duplicated word and fix typos
  block: bio: delete duplicated words
  block: bfq-iosched: fix duplicated word
  iocost_monitor: start from the oldest usage index
  iocost: Fix check condition of iocg abs_vdebt
  block: Remove callback typedefs for blk_mq_ops
  block: Use non _rcu version of list functions for tag_set_list
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  ...
2020-08-03 11:57:03 -07:00
Ingo Molnar
c1cc4784ce Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull the v5.9 RCU bits from Paul E. McKenney:

 - Documentation updates
 - Miscellaneous fixes
 - kfree_rcu updates
 - RCU tasks updates
 - Read-side scalability tests
 - SRCU updates
 - Torture-test updates

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-31 00:15:53 +02:00
Filipe Manana
5e548b3201 btrfs: do not set the full sync flag on the inode during page release
When removing an extent map at try_release_extent_mapping(), called through
the page release callback (btrfs_releasepage()), we always set the full
sync flag on the inode, which forces the next fsync to use a slower code
path.

This hurts performance for workloads that dirty an amount of data that
exceeds or is very close to the system's RAM memory and do frequent fsync
operations (like database servers can for example). In particular if there
are concurrent fsyncs against different files, by falling back to a full
fsync we do a lot more checksum lookups in the checksums btree, as we do
it for all the extents created in the current transaction, instead of only
the new ones since the last fsync. These checksums lookups not only take
some time but, more importantly, they also cause contention on the
checksums btree locks due to the concurrency with checksum insertions in
the btree by ordered extents from other inodes.

We actually don't need to set the full sync flag on the inode, because we
only remove extent maps that are in the list of modified extents if they
were created in a past transaction, in which case an fsync skips them as
it's pointless to log them. So stop setting the full fsync flag on the
inode whenever we remove an extent map.

This patch is part of a patchset that consists of 3 patches, which have
the following subjects:

1/3 btrfs: fix race between page release and a fast fsync
2/3 btrfs: release old extent maps during page release
3/3 btrfs: do not set the full sync flag on the inode during page release

Performance tests were ran against a branch (misc-next) containing the
whole patchset. The test exercises a workload where there are multiple
processes writing to files and fsyncing them (each writing and fsyncing
its own file), and in total the amount of data dirtied ranges from 2x to
4x the system's RAM memory (16GiB), so that the page release callback is
invoked frequently.

The following script, using fio, was used to perform the tests:

  $ cat test-fsync.sh
  #!/bin/bash

  DEV=/dev/sdk
  MNT=/mnt/sdk
  MOUNT_OPTIONS="-o ssd"
  MKFS_OPTIONS="-d single -m single"

  if [ $# -ne 3 ]; then
      echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ"
      exit 1
  fi

  NUM_JOBS=$1
  FILE_SIZE=$2
  FSYNC_FREQ=$3

  cat <<EOF > /tmp/fio-job.ini
  [writers]
  rw=write
  fsync=$FSYNC_FREQ
  fallocate=none
  group_reporting=1
  direct=0
  bs=64k
  ioengine=sync
  size=$FILE_SIZE
  directory=$MNT
  numjobs=$NUM_JOBS
  thread
  EOF

  echo "Using config:"
  echo
  cat /tmp/fio-job.ini
  echo

  mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null
  mount $MOUNT_OPTIONS $DEV $MNT
  fio /tmp/fio-job.ini
  umount $MNT

The tests were performed for different numbers of jobs, file sizes and
fsync frequency. A qemu VM using kvm was used, with 8 cores (the host has
12 cores, with cpu governance set to performance mode on all cores), 16GiB
of ram (the host has 64GiB) and using a NVMe device directly (without an
intermediary filesystem in the host). While running the tests, the host
was not used for anything else, to avoid disturbing the tests.

The obtained results were the following, and the last line printed by
fio is pasted (includes aggregated throughput and test run time).

    *****************************************************
    ****     1 job, 32GiB file, fsync frequency 1     ****
    *****************************************************

Before patchset:

WRITE: bw=29.1MiB/s (30.5MB/s), 29.1MiB/s-29.1MiB/s (30.5MB/s-30.5MB/s), io=32.0GiB (34.4GB), run=1127557-1127557msec

After patchset:

WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=32.0GiB (34.4GB), run=1119042-1119042msec
(+0.7% throughput, -0.8% run time)

    *****************************************************
    ****     2 jobs, 16GiB files, fsync frequency 1   ****
    *****************************************************

Before patchset:

WRITE: bw=33.5MiB/s (35.1MB/s), 33.5MiB/s-33.5MiB/s (35.1MB/s-35.1MB/s), io=32.0GiB (34.4GB), run=979000-979000msec

After patchset:

WRITE: bw=39.9MiB/s (41.8MB/s), 39.9MiB/s-39.9MiB/s (41.8MB/s-41.8MB/s), io=32.0GiB (34.4GB), run=821283-821283msec
(+19.1% throughput, -16.1% runtime)

    *****************************************************
    ****     4 jobs, 8GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=52.1MiB/s (54.6MB/s), 52.1MiB/s-52.1MiB/s (54.6MB/s-54.6MB/s), io=32.0GiB (34.4GB), run=629130-629130msec

After patchset:

WRITE: bw=71.8MiB/s (75.3MB/s), 71.8MiB/s-71.8MiB/s (75.3MB/s-75.3MB/s), io=32.0GiB (34.4GB), run=456357-456357msec
(+37.8% throughput, -27.5% runtime)

    *****************************************************
    ****     8 jobs, 4GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=76.1MiB/s (79.8MB/s), 76.1MiB/s-76.1MiB/s (79.8MB/s-79.8MB/s), io=32.0GiB (34.4GB), run=430708-430708msec

After patchset:

WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=245458-245458msec
(+74.7% throughput, -43.0% run time)

    *****************************************************
    ****    16 jobs, 2GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=74.7MiB/s (78.3MB/s), 74.7MiB/s-74.7MiB/s (78.3MB/s-78.3MB/s), io=32.0GiB (34.4GB), run=438625-438625msec

After patchset:

WRITE: bw=184MiB/s (193MB/s), 184MiB/s-184MiB/s (193MB/s-193MB/s), io=32.0GiB (34.4GB), run=177864-177864msec
(+146.3% throughput, -59.5% run time)

    *****************************************************
    ****    32 jobs, 2GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=72.6MiB/s (76.1MB/s), 72.6MiB/s-72.6MiB/s (76.1MB/s-76.1MB/s), io=64.0GiB (68.7GB), run=902615-902615msec

After patchset:

WRITE: bw=227MiB/s (238MB/s), 227MiB/s-227MiB/s (238MB/s-238MB/s), io=64.0GiB (68.7GB), run=288936-288936msec
(+212.7% throughput, -68.0% run time)

    *****************************************************
    ****    64 jobs, 1GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=98.8MiB/s (104MB/s), 98.8MiB/s-98.8MiB/s (104MB/s-104MB/s), io=64.0GiB (68.7GB), run=663126-663126msec

After patchset:

WRITE: bw=294MiB/s (308MB/s), 294MiB/s-294MiB/s (308MB/s-308MB/s), io=64.0GiB (68.7GB), run=222940-222940msec
(+197.6% throughput, -66.4% run time)

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:48 +02:00
Filipe Manana
fbc2bd7e7a btrfs: release old extent maps during page release
When removing an extent map at try_release_extent_mapping(), called through
the page release callback (btrfs_releasepage()), we never release an extent
map that is in the list of modified extents. This is to prevent races with
a concurrent fsync using the fast path, which could lead to not logging an
extent created in the current transaction.

However we can safely remove an extent map created in a past transaction
that is still in the list of modified extents (because no one fsynced yet
the inode after that transaction got commited), because such extents are
skipped during an fsync as it is pointless to log them. This change does
that.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:48 +02:00
Filipe Manana
3d6448e631 btrfs: fix race between page release and a fast fsync
When releasing an extent map, done through the page release callback, we
can race with an ongoing fast fsync and cause the fsync to miss a new
extent and not log it. The steps for this to happen are the following:

1) A page is dirtied for some inode I;

2) Writeback for that page is triggered by a path other than fsync, for
   example by the system due to memory pressure;

3) When the ordered extent for the extent (a single 4K page) finishes,
   we unpin the corresponding extent map and set its generation to N,
   the current transaction's generation;

4) The btrfs_releasepage() callback is invoked by the system due to
   memory pressure for that no longer dirty page of inode I;

5) At the same time, some task calls fsync on inode I, joins transaction
   N, and at btrfs_log_inode() it sees that the inode does not have the
   full sync flag set, so we proceed with a fast fsync. But before we get
   into btrfs_log_changed_extents() and lock the inode's extent map tree:

6) Through btrfs_releasepage() we end up at try_release_extent_mapping()
   and we remove the extent map for the new 4Kb extent, because it is
   neither pinned anymore nor locked. By calling remove_extent_mapping(),
   we remove the extent map from the list of modified extents, since the
   extent map does not have the logging flag set. We unlock the inode's
   extent map tree;

7) The task doing the fast fsync now enters btrfs_log_changed_extents(),
   locks the inode's extent map tree and iterates its list of modified
   extents, which no longer has the 4Kb extent in it, so it does not log
   the extent;

8) The fsync finishes;

9) Before transaction N is committed, a power failure happens. After
   replaying the log, the 4K extent of inode I will be missing, since
   it was not logged due to the race with try_release_extent_mapping().

So fix this by teaching try_release_extent_mapping() to not remove an
extent map if it's still in the list of modified extents.

Fixes: ff44c6e36d ("Btrfs: do not hold the write_lock on the extent tree while logging")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00