linux-toradex.git/fs/btrfs, branch v5.0

Merge tag 'for-5.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2019-02-03T16:48:33+00:00

Pull btrfs fixes from David Sterba:

 - regression fix: transaction commit can run away due to delayed ref
   waiting heuristic, this is not necessary now because of the proper
   reservation mechanism introduced in 5.0

 - regression fix: potential crash due to use-before-check of an ERR_PTR
   return value

 - fix for transaction abort during transaction commit that needs to
   properly clean up pending block groups

 - fix deadlock during b-tree node/leaf splitting, when this happens on
   some of the fundamental trees, we must prevent new tree block
   allocation to re-enter indirectly via the block group flushing path

 - potential memory leak after errors during mount

* tag 'for-5.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: On error always free subvol_name in btrfs_mount
  btrfs: clean up pending block groups when transaction commit aborts
  btrfs: fix potential oops in device_list_add
  btrfs: don't end the transaction for delayed refs in throttle
  Btrfs: fix deadlock when allocating tree block during leaf/node split

btrfs: On error always free subvol_name in btrfs_mount

2019-01-30T17:16:47+00:00

The subvol_name is allocated in btrfs_parse_subvol_options and is
consumed and freed in mount_subvol.  Add a free to the error paths that
don't call mount_subvol so that it is guaranteed that subvol_name is
freed when an error happens.

Fixes: 312c89fbca06 ("btrfs: cleanup btrfs_mount() using btrfs_mount_root()")
Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Nikolay Borisov 
Signed-off-by: "Eric W. Biederman" 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: clean up pending block groups when transaction commit aborts

2019-01-30T17:16:47+00:00

The fstests generic/475 stresses transaction aborts and can reveal
space accounting or use-after-free bugs regarding block goups.

In this case the pending block groups that remain linked to the
structures after transaction commit aborts in the middle.

The corrupted slabs lead to failures in following tests, eg. generic/476

  [ 8172.752887] BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
  [ 8172.755799] #PF error: [normal kernel read fault]
  [ 8172.757571] PGD 661ae067 P4D 661ae067 PUD 3db8e067 PMD 0
  [ 8172.759000] Oops: 0000 [#1] PREEMPT SMP
  [ 8172.760209] CPU: 0 PID: 39 Comm: kswapd0 Tainted: G        W         5.0.0-rc2-default #408
  [ 8172.762495] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626cc-prebuilt.qemu-project.org 04/01/2014
  [ 8172.765772] RIP: 0010:shrink_page_list+0x2f9/0xe90
  [ 8172.770453] RSP: 0018:ffff967f00663b18 EFLAGS: 00010287
  [ 8172.771184] RAX: 0000000000000000 RBX: ffff967f00663c20 RCX: 0000000000000000
  [ 8172.772850] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8c0620ab20e0
  [ 8172.774629] RBP: ffff967f00663dd8 R08: 0000000000000000 R09: 0000000000000000
  [ 8172.776094] R10: ffff8c0620ab22f8 R11: ffff8c063f772688 R12: ffff967f00663b78
  [ 8172.777533] R13: ffff8c063f625600 R14: ffff8c063f625608 R15: dead000000000200
  [ 8172.778886] FS:  0000000000000000(0000) GS:ffff8c063d400000(0000) knlGS:0000000000000000
  [ 8172.780545] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 8172.781787] CR2: 0000000000000058 CR3: 000000004e962000 CR4: 00000000000006f0
  [ 8172.783547] Call Trace:
  [ 8172.784112]  shrink_inactive_list+0x194/0x410
  [ 8172.784747]  shrink_node_memcg.constprop.85+0x3a5/0x6a0
  [ 8172.785472]  shrink_node+0x62/0x1e0
  [ 8172.786011]  balance_pgdat+0x216/0x460
  [ 8172.786577]  kswapd+0xe3/0x4a0
  [ 8172.787085]  ? finish_wait+0x80/0x80
  [ 8172.787795]  ? balance_pgdat+0x460/0x460
  [ 8172.788799]  kthread+0x116/0x130
  [ 8172.789640]  ? kthread_create_on_node+0x60/0x60
  [ 8172.790323]  ret_from_fork+0x24/0x30
  [ 8172.794253] CR2: 0000000000000058

or accounting errors at umount time:

  [ 8159.537251] WARNING: CPU: 2 PID: 19031 at fs/btrfs/extent-tree.c:5987 btrfs_free_block_groups+0x3d5/0x410 [btrfs]
  [ 8159.543325] CPU: 2 PID: 19031 Comm: umount Tainted: G        W         5.0.0-rc2-default #408
  [ 8159.545472] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626cc-prebuilt.qemu-project.org 04/01/2014
  [ 8159.548155] RIP: 0010:btrfs_free_block_groups+0x3d5/0x410 [btrfs]
  [ 8159.554030] RSP: 0018:ffff967f079cbde8 EFLAGS: 00010206
  [ 8159.555144] RAX: 0000000001000000 RBX: ffff8c06366cf800 RCX: 0000000000000000
  [ 8159.556730] RDX: 0000000000000002 RSI: 0000000000000001 RDI: ffff8c06255ad800
  [ 8159.558279] RBP: ffff8c0637ac0000 R08: 0000000000000001 R09: 0000000000000000
  [ 8159.559797] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8c0637ac0108
  [ 8159.561296] R13: ffff8c0637ac0158 R14: 0000000000000000 R15: dead000000000100
  [ 8159.562852] FS:  00007f7f693b9fc0(0000) GS:ffff8c063d800000(0000) knlGS:0000000000000000
  [ 8159.564839] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 8159.566160] CR2: 00007f7f68fab7b0 CR3: 000000000aec7000 CR4: 00000000000006e0
  [ 8159.567898] Call Trace:
  [ 8159.568597]  close_ctree+0x17f/0x350 [btrfs]
  [ 8159.569628]  generic_shutdown_super+0x64/0x100
  [ 8159.570808]  kill_anon_super+0x14/0x30
  [ 8159.571857]  btrfs_kill_super+0x12/0xa0 [btrfs]
  [ 8159.573063]  deactivate_locked_super+0x29/0x60
  [ 8159.574234]  cleanup_mnt+0x3b/0x70
  [ 8159.575176]  task_work_run+0x98/0xc0
  [ 8159.576177]  exit_to_usermode_loop+0x83/0x90
  [ 8159.577315]  do_syscall_64+0x15b/0x180
  [ 8159.578339]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

This fix is based on 2 Josef's patches that used sideefects of
btrfs_create_pending_block_groups, this fix introduces the helper that
does what we need.

CC: stable@vger.kernel.org # 4.4+
CC: Josef Bacik 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: fix potential oops in device_list_add

2019-01-30T17:16:40+00:00

alloc_fs_devices() can return ERR_PTR(-ENOMEM), so dereferencing its
result before the check for IS_ERR() is a bad idea.

Fixes: d1a63002829a4 ("btrfs: add members to fs_devices to track fsid changes")
Reviewed-by: Nikolay Borisov 
Reviewed-by: Anand Jain 
Signed-off-by: Al Viro 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: don't end the transaction for delayed refs in throttle

2019-01-28T14:41:11+00:00

Previously callers to btrfs_end_transaction_throttle() would commit the
transaction if there wasn't enough delayed refs space.  This happens in
relocation, and if the fs is relatively empty we'll run out of delayed
refs space basically immediately, so we'll just be stuck in this loop of
committing the transaction over and over again.

This code existed because we didn't have a good feedback mechanism for
running delayed refs, but with the delayed refs rsv we do now.  Delete
this throttling code and let the btrfs_start_transaction() in relocation
deal with putting pressure on the delayed refs infrastructure.  With
this patch we no longer take 5 minutes to balance a metadata only fs.

Qu has submitted a fstest to catch slow balance or excessive transaction
commits. Steps to reproduce:

* create subvolume
* create many (eg. 16000) inlined files, of size 2KiB
* iteratively snapshot and touch several files to trigger metadata
  updates
* start balance -m

Reported-by: Qu Wenruo 
Fixes: 64403612b73a ("btrfs: rework btrfs_check_space_for_delayed_refs")
Signed-off-by: Josef Bacik 
[ add tags and steps to reproduce ]
Signed-off-by: David Sterba

Btrfs: fix deadlock when allocating tree block during leaf/node split

2019-01-28T14:04:58+00:00

When splitting a leaf or node from one of the trees that are modified when
flushing pending block groups (extent, chunk, device and free space trees),
we need to allocate a new tree block, which in turn can result in the need
to allocate a new block group. After allocating the new block group we may
need to flush new block groups that were previously allocated during the
course of the current transaction, which is what may cause a deadlock due
to attempts to write lock twice the same leaf or node, as when splitting
a leaf or node we are holding a write lock on it and its parent node.

The same type of deadlock can also happen when increasing the tree's
height, since we are holding a lock on the existing root while allocating
the tree block to use as the new root node.

An example trace when the deadlock happens during the leaf split path is:

  [27175.293054] CPU: 0 PID: 3005 Comm: kworker/u17:6 Tainted: G        W         4.19.16 #1
  [27175.293942] Hardware name: Penguin Computing Relion 1900/MD90-FS0-ZB-XX, BIOS R15 06/25/2018
  [27175.294846] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
  (...)
  [27175.298384] RSP: 0018:ffffab2087107758 EFLAGS: 00010246
  [27175.299269] RAX: 0000000000000bbd RBX: ffff9fadc7141c48 RCX: 0000000000000001
  [27175.300155] RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffff9fadc7141c48
  [27175.301023] RBP: 0000000000000001 R08: ffff9faeb6ac1040 R09: ffff9fa9c0000000
  [27175.301887] R10: 0000000000000000 R11: 0000000000000040 R12: ffff9fb21aac8000
  [27175.302743] R13: ffff9fb1a64d6a20 R14: 0000000000000001 R15: ffff9fb1a64d6a18
  [27175.303601] FS:  0000000000000000(0000) GS:ffff9fb21fa00000(0000) knlGS:0000000000000000
  [27175.304468] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [27175.305339] CR2: 00007fdc8743ead8 CR3: 0000000763e0a006 CR4: 00000000003606f0
  [27175.306220] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [27175.307087] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [27175.307940] Call Trace:
  [27175.308802]  btrfs_search_slot+0x779/0x9a0 [btrfs]
  [27175.309669]  ? update_space_info+0xba/0xe0 [btrfs]
  [27175.310534]  btrfs_insert_empty_items+0x67/0xc0 [btrfs]
  [27175.311397]  btrfs_insert_item+0x60/0xd0 [btrfs]
  [27175.312253]  btrfs_create_pending_block_groups+0xee/0x210 [btrfs]
  [27175.313116]  do_chunk_alloc+0x25f/0x300 [btrfs]
  [27175.313984]  find_free_extent+0x706/0x10d0 [btrfs]
  [27175.314855]  btrfs_reserve_extent+0x9b/0x1d0 [btrfs]
  [27175.315707]  btrfs_alloc_tree_block+0x100/0x5b0 [btrfs]
  [27175.316548]  split_leaf+0x130/0x610 [btrfs]
  [27175.317390]  btrfs_search_slot+0x94d/0x9a0 [btrfs]
  [27175.318235]  btrfs_insert_empty_items+0x67/0xc0 [btrfs]
  [27175.319087]  alloc_reserved_file_extent+0x84/0x2c0 [btrfs]
  [27175.319938]  __btrfs_run_delayed_refs+0x596/0x1150 [btrfs]
  [27175.320792]  btrfs_run_delayed_refs+0xed/0x1b0 [btrfs]
  [27175.321643]  delayed_ref_async_start+0x81/0x90 [btrfs]
  [27175.322491]  normal_work_helper+0xd0/0x320 [btrfs]
  [27175.323328]  ? move_linked_works+0x6e/0xa0
  [27175.324160]  process_one_work+0x191/0x370
  [27175.324976]  worker_thread+0x4f/0x3b0
  [27175.325763]  kthread+0xf8/0x130
  [27175.326531]  ? rescuer_thread+0x320/0x320
  [27175.327284]  ? kthread_create_worker_on_cpu+0x50/0x50
  [27175.328027]  ret_from_fork+0x35/0x40
  [27175.328741] ---[ end trace 300a1b9f0ac30e26 ]---

Fix this by preventing the flushing of new blocks groups when splitting a
leaf/node and when inserting a new root node for one of the trees modified
by the flushing operation, similar to what is done when COWing a node/leaf
from on of these trees.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202383
Reported-by: Eli V 
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana 
Signed-off-by: David Sterba

Merge tag 'for-5.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2019-01-20T18:35:26+00:00

Pull btrfs fixes from David Sterba:
 "A handful of fixes (some of them in testing for a long time):

   - fix some test failures regarding cleanup after transaction abort

   - revert of a patch that could cause a deadlock

   - delayed iput fixes, that can help in ENOSPC situation when there's
     low space and a lot data to write"

* tag 'for-5.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: wakeup cleaner thread when adding delayed iput
  btrfs: run delayed iputs before committing
  btrfs: wait on ordered extents on abort cleanup
  btrfs: handle delayed ref head accounting cleanup in abort
  Revert "btrfs: balance dirty metadata pages in btrfs_finish_ordered_io"

btrfs: wakeup cleaner thread when adding delayed iput

2019-01-18T16:27:23+00:00

The cleaner thread usually takes care of delayed iputs, with the
exception of the btrfs_end_transaction_throttle path.  Delaying iputs
means we are potentially delaying the eviction of an inode and it's
respective space.  The cleaner thread only gets woken up every 30
seconds, or when we require space.  If there are a lot of inodes that
need to be deleted we could induce a serious amount of latency while we
wait for these inodes to be evicted.  So instead wakeup the cleaner if
it's not already awake to process any new delayed iputs we add to the
list.  If we suddenly need space we will less likely be backed up
behind a bunch of inodes that are waiting to be deleted, and we could
possibly free space before we need to get into the flushing logic which
will save us some latency.

Reviewed-by: Filipe Manana 
Signed-off-by: Josef Bacik 
Signed-off-by: David Sterba

btrfs: run delayed iputs before committing

2019-01-18T16:27:21+00:00

Delayed iputs means we can have final iputs of deleted inodes in the
queue, which could potentially generate a lot of pinned space that could
be free'd.  So before we decide to commit the transaction for ENOPSC
reasons, run the delayed iputs so that any potential space is free'd up.
If there is and we freed enough we can then commit the transaction and
potentially be able to make our reservation.

Reviewed-by: Omar Sandoval 
Signed-off-by: Josef Bacik 
Signed-off-by: David Sterba

btrfs: wait on ordered extents on abort cleanup

2019-01-18T16:24:19+00:00

If we flip read-only before we initiate writeback on all dirty pages for
ordered extents we've created then we'll have ordered extents left over
on umount, which results in all sorts of bad things happening.  Fix this
by making sure we wait on ordered extents if we have to do the aborted
transaction cleanup stuff.

generic/475 can produce this warning:

 [ 8531.177332] WARNING: CPU: 2 PID: 11997 at fs/btrfs/disk-io.c:3856 btrfs_free_fs_root+0x95/0xa0 [btrfs]
 [ 8531.183282] CPU: 2 PID: 11997 Comm: umount Tainted: G        W 5.0.0-rc1-default+ #394
 [ 8531.185164] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS rel-1.11.2-0-gf9626cc-prebuilt.qemu-project.org 04/01/2014
 [ 8531.187851] RIP: 0010:btrfs_free_fs_root+0x95/0xa0 [btrfs]
 [ 8531.193082] RSP: 0018:ffffb1ab86163d98 EFLAGS: 00010286
 [ 8531.194198] RAX: ffff9f3449494d18 RBX: ffff9f34a2695000 RCX:0000000000000000
 [ 8531.195629] RDX: 0000000000000002 RSI: 0000000000000001 RDI:0000000000000000
 [ 8531.197315] RBP: ffff9f344e930000 R08: 0000000000000001 R09:0000000000000000
 [ 8531.199095] R10: 0000000000000000 R11: ffff9f34494d4ff8 R12:ffffb1ab86163dc0
 [ 8531.200870] R13: ffff9f344e9300b0 R14: ffffb1ab86163db8 R15:0000000000000000
 [ 8531.202707] FS:  00007fc68e949fc0(0000) GS:ffff9f34bd800000(0000)knlGS:0000000000000000
 [ 8531.204851] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [ 8531.205942] CR2: 00007ffde8114dd8 CR3: 000000002dfbd000 CR4:00000000000006e0
 [ 8531.207516] Call Trace:
 [ 8531.208175]  btrfs_free_fs_roots+0xdb/0x170 [btrfs]
 [ 8531.210209]  ? wait_for_completion+0x5b/0x190
 [ 8531.211303]  close_ctree+0x157/0x350 [btrfs]
 [ 8531.212412]  generic_shutdown_super+0x64/0x100
 [ 8531.213485]  kill_anon_super+0x14/0x30
 [ 8531.214430]  btrfs_kill_super+0x12/0xa0 [btrfs]
 [ 8531.215539]  deactivate_locked_super+0x29/0x60
 [ 8531.216633]  cleanup_mnt+0x3b/0x70
 [ 8531.217497]  task_work_run+0x98/0xc0
 [ 8531.218397]  exit_to_usermode_loop+0x83/0x90
 [ 8531.219324]  do_syscall_64+0x15b/0x180
 [ 8531.220192]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
 [ 8531.221286] RIP: 0033:0x7fc68e5e4d07
 [ 8531.225621] RSP: 002b:00007ffde8116608 EFLAGS: 00000246 ORIG_RAX:00000000000000a6
 [ 8531.227512] RAX: 0000000000000000 RBX: 00005580c2175970 RCX:00007fc68e5e4d07
 [ 8531.229098] RDX: 0000000000000001 RSI: 0000000000000000 RDI:00005580c2175b80
 [ 8531.230730] RBP: 0000000000000000 R08: 00005580c2175ba0 R09:00007ffde8114e80
 [ 8531.232269] R10: 0000000000000000 R11: 0000000000000246 R12:00005580c2175b80
 [ 8531.233839] R13: 00007fc68eac61c4 R14: 00005580c2175a68 R15:0000000000000000

Leaving a tree in the rb-tree:

3853 void btrfs_free_fs_root(struct btrfs_root *root)
3854 {
3855         iput(root->ino_cache_inode);
3856         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));

CC: stable@vger.kernel.org
Reviewed-by: Nikolay Borisov 
Signed-off-by: Josef Bacik 
[ add stacktrace ]
Signed-off-by: David Sterba