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Commit Graph

5058 Commits

Author SHA1 Message Date
Linus Torvalds
80e0c505b2 Merge branch 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "This has Mark Fasheh's patches to fix quota accounting during subvol
  deletion, which we've been working on for a while now.  The patch is
  pretty small but it's a key fix.

  Otherwise it's a random assortment"

* 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix balance range usage filters in 4.4-rc
  btrfs: qgroup: account shared subtree during snapshot delete
  Btrfs: use btrfs_get_fs_root in resolve_indirect_ref
  btrfs: qgroup: fix quota disable during rescan
  Btrfs: fix race between cleaner kthread and space cache writeout
  Btrfs: fix scrub preventing unused block groups from being deleted
  Btrfs: fix race between scrub and block group deletion
  btrfs: fix rcu warning during device replace
  btrfs: Continue replace when set_block_ro failed
  btrfs: fix clashing number of the enhanced balance usage filter
  Btrfs: fix the number of transaction units needed to remove a block group
  Btrfs: use global reserve when deleting unused block group after ENOSPC
  Btrfs: tests: checking for NULL instead of IS_ERR()
  btrfs: fix signed overflows in btrfs_sync_file
2015-11-27 15:45:45 -08:00
Holger Hoffstätte
dba72cb30b btrfs: fix balance range usage filters in 4.4-rc
There's a regression in 4.4-rc since commit bc3094673f
(btrfs: extend balance filter usage to take minimum and maximum) in that
existing (non-ranged) balance with -dusage=x no longer works; all chunks
are skipped.

After staring at the code for a while and wondering why a non-ranged
balance would even need min and max thresholds (..which then were not
set correctly, leading to the bug) I realized that the only problem
was the fact that the filter functions were named wrong, thanks to
patching copypasta. Simply renaming both functions lets the existing
btrfs-progs call balance with -dusage=x and now the non-ranged filter
function is invoked, properly using only a single chunk limit.

Signed-off-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Fixes: bc3094673f ("btrfs: extend balance filter usage to take minimum and maximum")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:27:33 -08:00
Mark Fasheh
82bd101b52 btrfs: qgroup: account shared subtree during snapshot delete
Commit 0ed4792 ('btrfs: qgroup: Switch to new extent-oriented qgroup
mechanism.') removed our qgroup accounting during
btrfs_drop_snapshot(). Predictably, this results in qgroup numbers
going bad shortly after a snapshot is removed.

Fix this by adding a dirty extent record when we encounter extents during
our shared subtree walk. This effectively restores the functionality we had
with the original shared subtree walking code in 1152651 (btrfs: qgroup:
account shared subtrees during snapshot delete).

The idea with the original patch (and this one) is that shared subtrees can
get skipped during drop_snapshot. The shared subtree walk then allows us a
chance to visit those extents and add them to the qgroup work for later
processing. This ultimately makes the accounting for drop snapshot work.

The new qgroup code nicely handles all the other extents during the tree
walk via the ref dec/inc functions so we don't have to add actions beyond
what we had originally.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:27:33 -08:00
Josef Bacik
2d9e977610 Btrfs: use btrfs_get_fs_root in resolve_indirect_ref
The backref code will look up the fs_root we're trying to resolve our indirect
refs for, unfortunately we use btrfs_read_fs_root_no_name, which returns -ENOENT
if the ref is 0.  This isn't helpful for the qgroup stuff with snapshot delete
as it won't be able to search down the snapshot we are deleting, which will
cause us to miss roots.  So use btrfs_get_fs_root and send false for check_ref
so we can always get the root we're looking for.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:22:08 -08:00
Justin Maggard
967ef5131e btrfs: qgroup: fix quota disable during rescan
There's a race condition that leads to a NULL pointer dereference if you
disable quotas while a quota rescan is running.  To fix this, we just need
to wait for the quota rescan worker to actually exit before tearing down
the quota structures.

Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:22:08 -08:00
Filipe Manana
036a9348dc Btrfs: fix race between cleaner kthread and space cache writeout
When a block group becomes unused and the cleaner kthread is currently
running, we can end up getting the current transaction aborted with error
-ENOENT when we try to commit the transaction, leading to the following
trace:

  [59779.258768] WARNING: CPU: 3 PID: 5990 at fs/btrfs/extent-tree.c:3740 btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]()
  [59779.272594] BTRFS: Transaction aborted (error -2)
  (...)
  [59779.291137] Call Trace:
  [59779.291621]  [<ffffffff812566f4>] dump_stack+0x4e/0x79
  [59779.292543]  [<ffffffff8104d0a6>] warn_slowpath_common+0x9f/0xb8
  [59779.293435]  [<ffffffffa04cb81f>] ? btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
  [59779.295000]  [<ffffffff8104d107>] warn_slowpath_fmt+0x48/0x50
  [59779.296138]  [<ffffffffa04c2721>] ? write_one_cache_group.isra.32+0x77/0x82 [btrfs]
  [59779.297663]  [<ffffffffa04cb81f>] btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
  [59779.299141]  [<ffffffffa0549b0d>] commit_cowonly_roots+0x1de/0x261 [btrfs]
  [59779.300359]  [<ffffffffa04dd5b6>] btrfs_commit_transaction+0x4c4/0x99c [btrfs]
  [59779.301805]  [<ffffffffa04b5df4>] btrfs_sync_fs+0x145/0x1ad [btrfs]
  [59779.302893]  [<ffffffff81196634>] sync_filesystem+0x7f/0x93
  (...)
  [59779.318186] ---[ end trace 577e2daff90da33a ]---

The following diagram illustrates a sequence of steps leading to this
problem:

       CPU 1                                             CPU 2

                           <at transaction N>

                                                        adds bg A to list
                                                        fs_info->unused_bgs

                                                        adds bg B to list
                                                        fs_info->unused_bgs

                           <transaction kthread
                            commits transaction N
                            and wakes up the
                            cleaner kthread>

  cleaner kthread
    delete_unused_bgs()

      sees bg A in list
      fs_info->unused_bgs

      btrfs_start_transaction()

                           <transaction N + 1 starts>

      deletes bg A

                                                        update_block_group(bg C)

                                                          --> adds bg C to list
                                                              fs_info->unused_bgs

      deletes bg B

      sees bg C in the list
      fs_info->unused_bgs

      btrfs_remove_chunk(bg C)
        btrfs_remove_block_group(bg C)

          --> checks if the block group
              is in a dirty list, and
              because it isn't now, it
              does nothing

          --> the block group item
              is deleted from the
              extent tree

                                                          --> adds bg C to list
                                                              transaction->dirty_bgs

                                                         some task calls
                                                         btrfs_commit_transaction(t N + 1)
                                                           commit_cowonly_roots()
                                                             btrfs_write_dirty_block_groups()
                                                               --> sees bg C in cur_trans->dirty_bgs
                                                               --> calls write_one_cache_group()
                                                                   which returns -ENOENT because
                                                                   it did not find the block group
                                                                   item in the extent tree
                                                               --> transaction aborte with -ENOENT
                                                                   because write_one_cache_group()
                                                                   returned that error

So fix this by adding a block group to the list of dirty block groups
before adding it to the list of unused block groups.

This happened on a stress test using fsstress plus concurrent calls to
fallocate 20G and truncate (releasing part of the space allocated with
fallocate).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:22:08 -08:00
Filipe Manana
758f2dfcf8 Btrfs: fix scrub preventing unused block groups from being deleted
Currently scrub can race with the cleaner kthread when the later attempts
to delete an unused block group, and the result is preventing the cleaner
kthread from ever deleting later the block group - unless the block group
becomes used and unused again. The following diagram illustrates that
race:

              CPU 1                                 CPU 2

 cleaner kthread
   btrfs_delete_unused_bgs()

     gets block group X from
     fs_info->unused_bgs and
     removes it from that list

                                             scrub_enumerate_chunks()

                                               searches device tree using
                                               its commit root

                                               finds device extent for
                                               block group X

                                               gets block group X from the tree
                                               fs_info->block_group_cache_tree
                                               (via btrfs_lookup_block_group())

                                               sets bg X to RO

     sees the block group is
     already RO and therefore
     doesn't delete it nor adds
     it back to unused list

So fix this by making scrub add the block group again to the list of
unused block groups if the block group is still unused when it finished
scrubbing it and it hasn't been removed already.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:22:08 -08:00
Filipe Manana
020d5b7366 Btrfs: fix race between scrub and block group deletion
Scrub can race with the cleaner kthread deleting block groups that are
unused (and with relocation too) leading to a failure with error -EINVAL
that gets returned to user space.

The following diagram illustrates how it happens:

              CPU 1                                 CPU 2

 cleaner kthread
   btrfs_delete_unused_bgs()

     gets block group X from
     fs_info->unused_bgs

     sets block group to RO

       btrfs_remove_chunk(bg X)

         deletes device extents

                                         scrub_enumerate_chunks()

                                           searches device tree using
                                           its commit root

                                           finds device extent for
                                           block group X

                                           gets block group X from the tree
                                           fs_info->block_group_cache_tree
                                           (via btrfs_lookup_block_group())

                                           sets bg X to RO (again)

          btrfs_remove_block_group(bg X)

            deletes block group from
            fs_info->block_group_cache_tree

            removes extent map from
            fs_info->mapping_tree

                                               scrub_chunk(offset X)

                                                 searches fs_info->mapping_tree
                                                 for extent map starting at
                                                 offset X

                                                    --> doesn't find any such
                                                        extent map
                                                    --> returns -EINVAL and scrub
                                                        errors out to userspace
                                                        with -EINVAL

Fix this by dealing with an extent map lookup failure as an indicator of
block group deletion.
Issue reproduced with fstest btrfs/071.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:51 -08:00
David Sterba
31388ab2ed btrfs: fix rcu warning during device replace
The test btrfs/011 triggers a rcu warning
Reviewed-by: Anand Jain <anand.jain@oracle.com>

===============================
[ INFO: suspicious RCU usage. ]
4.4.0-rc1-default+ #286 Tainted: G        W
-------------------------------
fs/btrfs/volumes.c:1977 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
4 locks held by btrfs/28786:

0:  (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+...}, at: [<ffffffffa00bc785>] btrfs_dev_replace_finishing+0x45/0xa00 [btrfs]
1:  (uuid_mutex){+.+.+.}, at: [<ffffffffa00bc84f>] btrfs_dev_replace_finishing+0x10f/0xa00 [btrfs]
2:  (&fs_devs->device_list_mutex){+.+.+.}, at: [<ffffffffa00bc868>] btrfs_dev_replace_finishing+0x128/0xa00 [btrfs]
3:  (&fs_info->chunk_mutex){+.+...}, at: [<ffffffffa00bc87d>] btrfs_dev_replace_finishing+0x13d/0xa00 [btrfs]

stack backtrace:
CPU: 0 PID: 28786 Comm: btrfs Tainted: G        W       4.4.0-rc1-default+ #286
Hardware name: Intel Corporation SandyBridge Platform/To be filled by O.E.M., BIOS ASNBCPT1.86C.0031.B00.1006301607 06/30/2010
0000000000000001 ffff8800a07dfb48 ffffffff8141d47b 0000000000000001
0000000000000001 0000000000000000 ffff8801464a4f00 ffff8800a07dfb78
ffffffff810cd883 ffff880146eb9400 ffff8800a3698600 ffff8800a33fe220
Call Trace:
[<ffffffff8141d47b>] dump_stack+0x4f/0x74
[<ffffffff810cd883>] lockdep_rcu_suspicious+0x103/0x140
[<ffffffffa0071261>] btrfs_rm_dev_replace_remove_srcdev+0x111/0x130 [btrfs]
[<ffffffff810d354d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff81449536>] ? __percpu_counter_sum+0x66/0x80
[<ffffffffa00bcc15>] btrfs_dev_replace_finishing+0x4d5/0xa00 [btrfs]
[<ffffffffa00bc96e>] ? btrfs_dev_replace_finishing+0x22e/0xa00 [btrfs]
[<ffffffffa00a8795>] ? btrfs_scrub_dev+0x415/0x6d0 [btrfs]
[<ffffffffa003ea69>] ? btrfs_start_transaction+0x9/0x20 [btrfs]
[<ffffffffa00bda79>] btrfs_dev_replace_start+0x339/0x590 [btrfs]
[<ffffffff81196aa5>] ? __might_fault+0x95/0xa0
[<ffffffffa0078638>] btrfs_ioctl_dev_replace+0x118/0x160 [btrfs]
[<ffffffff811409c6>] ? stack_trace_call+0x46/0x70
[<ffffffffa007c914>] ? btrfs_ioctl+0x24/0x1770 [btrfs]
[<ffffffffa007ce43>] btrfs_ioctl+0x553/0x1770 [btrfs]
[<ffffffff811409c6>] ? stack_trace_call+0x46/0x70
[<ffffffff811d6eb1>] ? do_vfs_ioctl+0x21/0x5a0
[<ffffffff811d6f1c>] do_vfs_ioctl+0x8c/0x5a0
[<ffffffff811e3336>] ? __fget_light+0x86/0xb0
[<ffffffff811e3369>] ? __fdget+0x9/0x20
[<ffffffff811d7451>] ? SyS_ioctl+0x21/0x80
[<ffffffff811d7483>] SyS_ioctl+0x53/0x80
[<ffffffff81b1efd7>] entry_SYSCALL_64_fastpath+0x12/0x6f

This is because of unprotected use of rcu_dereference in
btrfs_scratch_superblocks. We can't add rcu locks around the whole
function because we read the superblock.

The fix will use the rcu string buffer directly without the rcu locking.
Thi is safe as the device will not go away in the meantime. We're
holding the device list mutexes.

Restructuring the code to narrow down the rcu section turned out to be
impossible, we need to call filp_open (through update_dev_time) on the
buffer and this could call kmalloc/__might_sleep. We could call kstrdup
with GFP_ATOMIC but it's not absolutely necessary.

Fixes: 12b1c2637b (Btrfs: enhance btrfs_scratch_superblock to scratch all superblocks)
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:51 -08:00
Zhaolei
76a8efa171 btrfs: Continue replace when set_block_ro failed
xfstests/011 failed in node with small_size filesystem.
Can be reproduced by following script:
  DEV_LIST="/dev/vdd /dev/vde"
  DEV_REPLACE="/dev/vdf"

  do_test()
  {
      local mkfs_opt="$1"
      local size="$2"

      dmesg -c >/dev/null
      umount $SCRATCH_MNT &>/dev/null

      echo  mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}"
      mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1
      mount "${DEV_LIST[0]}" $SCRATCH_MNT

      echo -n "Writing big files"
      dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1
      for ((i = 1; i <= size; i++)); do
          echo -n .
          /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1
      done
      echo

      echo Start replace
      btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || {
          dmesg
          return 1
      }
      return 0
  }

  # Set size to value near fs size
  # for example, 1897 can trigger this bug in 2.6G device.
  #
  ./do_test "-d raid1 -m raid1" 1897

System will report replace fail with following warning in dmesg:
 [  134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started
 [  135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28
 [  135.543505] ------------[ cut here ]------------
 [  135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440()
 [  135.545276] Modules linked in:
 [  135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256
 [  135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
 [  135.547798]  ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000
 [  135.548774]  ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4
 [  135.549774]  ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70
 [  135.550758] Call Trace:
 [  135.551086]  [<ffffffff817fe7b5>] dump_stack+0x44/0x55
 [  135.551737]  [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0
 [  135.552487]  [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20
 [  135.553211]  [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440
 [  135.554051]  [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0
 [  135.554722]  [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0
 [  135.555506]  [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0
 [  135.556304]  [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580
 [  135.557009]  [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0
 [  135.557855]  [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70
 [  135.558669]  [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90
 [  135.559374]  [<ffffffff81202124>] SyS_ioctl+0x74/0x80
 [  135.559987]  [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f
 [  135.560842] ---[ end trace 2a5c1fc3205abbdd ]---

Reason:
 When big data writen to fs, the whole free space will be allocated
 for data chunk.
 And operation as scrub need to set_block_ro(), and when there is
 only one metadata chunk in system(or other metadata chunks
 are all full), the function will try to allocate a new chunk,
 and failed because no space in device.

Fix:
 When set_block_ro failed for metadata chunk, it is not a problem
 because scrub_lock paused commit_trancaction in same time, and
 metadata are always cowed, so the on-the-fly writepages will not
 write data into same place with scrub/replace.
 Let replace continue in this case is no problem.

Tested by above script, and xfstests/011, plus 100 times xfstests/070.

Changelog v1->v2:
1: Add detail comments in source and commit-message.
2: Add dmesg detail into commit-message.
3: Limit return value of -ENOSPC to be passed.
All suggested by: Filipe Manana <fdmanana@gmail.com>

Suggested-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:51 -08:00
David Sterba
da02c68989 btrfs: fix clashing number of the enhanced balance usage filter
I've accidentally picked an already used number for the enhanced usage
filter represented by BTRFS_BALANCE_ARGS_USAGE_RANGE, clashing with
BTRFS_BALANCE_ARGS_CONVERT. Introduced during the development phase,
no backward compatibility issues.

Reported-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: bc3094673f ("btrfs: extend balance filter usage to take minimum and maximum")
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Filipe Manana
7fd01182d1 Btrfs: fix the number of transaction units needed to remove a block group
We were using only 1 transaction unit when attempting to delete an unused
block group but in reality we need 3 + N units, where N corresponds to the
number of stripes. We were accounting only for the addition of the orphan
item (for the block group's free space cache inode) but we were not
accounting that we need to delete one block group item from the extent
tree, one free space item from the tree of tree roots and N device extent
items from the device tree.

While one unit is not enough, it worked most of the time because for each
single unit we are too pessimistic and assume an entire tree path, with
the highest possible heigth (8), needs to be COWed with eventual node
splits at every possible level in the tree, so there was usually enough
reserved space for removing all the items and adding the orphan item.

However after adding the orphan item, writepages() can by called by the VM
subsystem against the btree inode when we are under memory pressure, which
causes writeback to start for the nodes we COWed before, this forces the
operation to remove the free space item to COW again some (or all of) the
same nodes (in the tree of tree roots). Even without writepages() being
called, we could fail with ENOSPC because these items are located in
multiple trees and one of them might have a higher heigth and require
node/leaf splits at many levels, exhausting all the reserved space before
removing all the items and adding the orphan.

In the kernel 4.0 release, commit 3d84be7991 ("Btrfs: fix BUG_ON in
btrfs_orphan_add() when delete unused block group"), we attempted to fix
a BUG_ON due to ENOSPC when trying to add the orphan item by making the
cleaner kthread reserve one transaction unit before attempting to remove
the block group, but this was not enough. We had a couple user reports
still hitting the same BUG_ON after 4.0, like Stefan Priebe's report on
a 4.2-rc6 kernel for example:

    http://www.spinics.net/lists/linux-btrfs/msg46070.html

So fix this by reserving all the necessary units of metadata.

Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Fixes: 3d84be7991 ("Btrfs: fix BUG_ON in btrfs_orphan_add() when delete unused block group")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Filipe Manana
8eab77ff16 Btrfs: use global reserve when deleting unused block group after ENOSPC
It's possible to reach a state where the cleaner kthread isn't able to
start a transaction to delete an unused block group due to lack of enough
free metadata space and due to lack of unallocated device space to allocate
a new metadata block group as well. If this happens try to use space from
the global block group reserve just like we do for unlink operations, so
that we don't reach a permanent state where starting a transaction for
filesystem operations (file creation, renames, etc) keeps failing with
-ENOSPC. Such an unfortunate state was observed on a machine where over
a dozen unused data block groups existed and the cleaner kthread was
failing to delete them due to ENOSPC error when attempting to start a
transaction, and even running balance with a -dusage=0 filter failed with
ENOSPC as well. Also unmounting and mounting again the filesystem didn't
help. Allowing the cleaner kthread to use the global block reserve to
delete the unused data block groups fixed the problem.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Dan Carpenter
89b6c8d1e4 Btrfs: tests: checking for NULL instead of IS_ERR()
btrfs_alloc_dummy_root() return an error pointer on failure, it never
returns NULL.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
David Sterba
9dcbeed4d7 btrfs: fix signed overflows in btrfs_sync_file
The calculation of range length in btrfs_sync_file leads to signed
overflow. This was caught by PaX gcc SIZE_OVERFLOW plugin.

https://forums.grsecurity.net/viewtopic.php?f=1&t=4284

The fsync call passes 0 and LLONG_MAX, the range length does not fit to
loff_t and overflows, but the value is converted to u64 so it silently
works as expected.

The minimal fix is a typecast to u64, switching functions to take
(start, end) instead of (start, len) would be more intrusive.

Coccinelle script found that there's one more opencoded calculation of
the length.

<smpl>
@@
loff_t start, end;
@@
* end - start
</smpl>

CC: stable@vger.kernel.org
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-25 05:19:50 -08:00
Linus Torvalds
e75cdf9898 Merge branch 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes and cleanups from Chris Mason:
 "Some of this got cherry-picked from a github repo this week, but I
  verified the patches.

  We have three small scrub cleanups and a collection of fixes"

* 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: Use fs_info directly in btrfs_delete_unused_bgs
  btrfs: Fix lost-data-profile caused by balance bg
  btrfs: Fix lost-data-profile caused by auto removing bg
  btrfs: Remove len argument from scrub_find_csum
  btrfs: Reduce unnecessary arguments in scrub_recheck_block
  btrfs: Use scrub_checksum_data and scrub_checksum_tree_block for scrub_recheck_block_checksum
  btrfs: Reset sblock->xxx_error stats before calling scrub_recheck_block_checksum
  btrfs: scrub: setup all fields for sblock_to_check
  btrfs: scrub: set error stats when tree block spanning stripes
  Btrfs: fix race when listing an inode's xattrs
  Btrfs: fix race leading to BUG_ON when running delalloc for nodatacow
  Btrfs: fix race leading to incorrect item deletion when dropping extents
  Btrfs: fix sleeping inside atomic context in qgroup rescan worker
  Btrfs: fix race waiting for qgroup rescan worker
  btrfs: qgroup: exit the rescan worker during umount
  Btrfs: fix extent accounting for partial direct IO writes
2015-11-13 16:30:29 -08:00
Zhao Lei
d5f2e33b92 btrfs: Use fs_info directly in btrfs_delete_unused_bgs
No need to use root->fs_info in btrfs_delete_unused_bgs(),
use fs_info directly instead.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:24 -08:00
Zhao Lei
2c9fe83552 btrfs: Fix lost-data-profile caused by balance bg
Reproduce:
 (In integration-4.3 branch)

 TEST_DEV=(/dev/vdg /dev/vdh)
 TEST_DIR=/mnt/tmp

 umount "$TEST_DEV" >/dev/null
 mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}"

 mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
 btrfs balance start -dusage=0 $TEST_DIR
 btrfs filesystem usage $TEST_DIR

 dd if=/dev/zero of="$TEST_DIR"/file count=100
 btrfs filesystem usage $TEST_DIR

Result:
 We can see "no data chunk" in first "btrfs filesystem usage":
 # btrfs filesystem usage $TEST_DIR
 Overall:
    ...
 Metadata,single: Size:8.00MiB, Used:0.00B
    /dev/vdg        8.00MiB
 Metadata,RAID1: Size:122.88MiB, Used:112.00KiB
    /dev/vdg      122.88MiB
    /dev/vdh      122.88MiB
 System,single: Size:4.00MiB, Used:0.00B
    /dev/vdg        4.00MiB
 System,RAID1: Size:8.00MiB, Used:16.00KiB
    /dev/vdg        8.00MiB
    /dev/vdh        8.00MiB
 Unallocated:
    /dev/vdg        1.06GiB
    /dev/vdh        1.07GiB

 And "data chunks changed from raid1 to single" in second
 "btrfs filesystem usage":
 # btrfs filesystem usage $TEST_DIR
 Overall:
    ...
 Data,single: Size:256.00MiB, Used:0.00B
    /dev/vdh      256.00MiB
 Metadata,single: Size:8.00MiB, Used:0.00B
    /dev/vdg        8.00MiB
 Metadata,RAID1: Size:122.88MiB, Used:112.00KiB
    /dev/vdg      122.88MiB
    /dev/vdh      122.88MiB
 System,single: Size:4.00MiB, Used:0.00B
    /dev/vdg        4.00MiB
 System,RAID1: Size:8.00MiB, Used:16.00KiB
    /dev/vdg        8.00MiB
    /dev/vdh        8.00MiB
 Unallocated:
    /dev/vdg        1.06GiB
    /dev/vdh      841.92MiB

Reason:
 btrfs balance delete last data chunk in case of no data in
 the filesystem, then we can see "no data chunk" by "fi usage"
 command.

 And when we do write operation to fs, the only available data
 profile is 0x0, result is all new chunks are allocated single type.

Fix:
 Allocate a data chunk explicitly to ensure we don't lose the
 raid profile for data.

Test:
 Test by above script, and confirmed the logic by debug output.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:20 -08:00
Zhao Lei
aefbe9a633 btrfs: Fix lost-data-profile caused by auto removing bg
Reproduce:
 (In integration-4.3 branch)

 TEST_DEV=(/dev/vdg /dev/vdh)
 TEST_DIR=/mnt/tmp

 umount "$TEST_DEV" >/dev/null
 mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}"

 mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
 umount "$TEST_DEV"

 mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
 btrfs filesystem usage $TEST_DIR

We can see the data chunk changed from raid1 to single:
 # btrfs filesystem usage $TEST_DIR
 Data,single: Size:8.00MiB, Used:0.00B
    /dev/vdg        8.00MiB
 #

Reason:
 When a empty filesystem mount with -o nospace_cache, the last
 data blockgroup will be auto-removed in umount.

 Then if we mount it again, there is no data chunk in the
 filesystem, so the only available data profile is 0x0, result
 is all new chunks are created as single type.

Fix:
 Don't auto-delete last blockgroup for a raid type.

Test:
 Test by above script, and confirmed the logic by debug output.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:16 -08:00
Zhao Lei
3b5753ec23 btrfs: Remove len argument from scrub_find_csum
It is useless.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:13 -08:00
Zhao Lei
affe4a5ae1 btrfs: Reduce unnecessary arguments in scrub_recheck_block
We don't need pass so many arguments for recheck sblock now,
this patch cleans them.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:10 -08:00
Zhao Lei
ba7cf9882b btrfs: Use scrub_checksum_data and scrub_checksum_tree_block for scrub_recheck_block_checksum
We can use existing scrub_checksum_data() and scrub_checksum_tree_block()
for scrub_recheck_block_checksum(), instead of write duplicated code.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:06 -08:00
Zhao Lei
772d233f5d btrfs: Reset sblock->xxx_error stats before calling scrub_recheck_block_checksum
We should reset sblock->xxx_error stats before calling
scrub_recheck_block_checksum().

Current code run correctly because all sblock are allocated by
k[cz]alloc(), and the error stats are not got changed.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:03 -08:00
Zhao Lei
4734b7ed79 btrfs: scrub: setup all fields for sblock_to_check
scrub_setup_recheck_block() isn't setup all necessary fields for
sblock_to_check because history reason.

So current code need more arguments in severial functions,
and more local variables, just to passing these lacked values to
necessary place.

This patch setup above fields to sblock_to_check in
scrub_setup_recheck_block(), for:
1: more cleanup for function arg, local variable
2: to make sblock_to_check complete, then we can use sblock_to_check
   without concern about some uninitialized member.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:27:00 -08:00
Zhao Lei
9799d2c32b btrfs: scrub: set error stats when tree block spanning stripes
It is better to show error stats to user when we found tree block
spanning stripes.

On a btrfs created by old version of btrfs-convert:
Before patch:
  # btrfs scrub start -B /dev/vdh
  scrub done for 8b342d35-2904-41ab-b3cb-2f929709cf47
          scrub started at Tue Aug 25 21:19:09 2015 and finished after 00:00:00
          total bytes scrubbed: 53.54MiB with 0 errors
  # dmesg
  ...
  [  128.711434] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832
  [  128.712744] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368
  ...

After patch:
  # btrfs scrub start -B /dev/vdh
  scrub done for ff7f844b-7a4e-4b1a-88a9-8252ab25be1b
          scrub started at Tue Aug 25 21:42:29 2015 and finished after 00:00:00
          total bytes scrubbed: 53.60MiB with 2 errors
          error details:
          corrected errors: 0, uncorrectable errors: 2, unverified errors: 0
  ERROR: There are uncorrectable errors.
  # dmesg
  ...omit...
  #

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-10 19:26:57 -08:00
Yaowei Bai
7cac0a8599 fs/btrfs/inode.c: remove unnecessary new_valid_dev() check
new_valid_dev() always returns 1, so the !new_valid_dev() check is not
needed.  Remove it.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-09 15:11:24 -08:00
Filipe Manana
f1cd1f0b7d Btrfs: fix race when listing an inode's xattrs
When listing a inode's xattrs we have a time window where we race against
a concurrent operation for adding a new hard link for our inode that makes
us not return any xattr to user space. In order for this to happen, the
first xattr of our inode needs to be at slot 0 of a leaf and the previous
leaf must still have room for an inode ref (or extref) item, and this can
happen because an inode's listxattrs callback does not lock the inode's
i_mutex (nor does the VFS does it for us), but adding a hard link to an
inode makes the VFS lock the inode's i_mutex before calling the inode's
link callback.

If we have the following leafs:

               Leaf X (has N items)                    Leaf Y

 [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ]  [ (257 XATTR_ITEM 12345), ... ]
           slot N - 2         slot N - 1              slot 0

The race illustrated by the following sequence diagram is possible:

       CPU 1                                               CPU 2

  btrfs_listxattr()

    searches for key (257 XATTR_ITEM 0)

    gets path with path->nodes[0] == leaf X
    and path->slots[0] == N

    because path->slots[0] is >=
    btrfs_header_nritems(leaf X), it calls
    btrfs_next_leaf()

    btrfs_next_leaf()
      releases the path

                                                   adds key (257 INODE_REF 666)
                                                   to the end of leaf X (slot N),
                                                   and leaf X now has N + 1 items

      searches for the key (257 INODE_REF 256),
      with path->keep_locks == 1, because that
      is the last key it saw in leaf X before
      releasing the path

      ends up at leaf X again and it verifies
      that the key (257 INODE_REF 256) is no
      longer the last key in leaf X, so it
      returns with path->nodes[0] == leaf X
      and path->slots[0] == N, pointing to
      the new item with key (257 INODE_REF 666)

    btrfs_listxattr's loop iteration sees that
    the type of the key pointed by the path is
    different from the type BTRFS_XATTR_ITEM_KEY
    and so it breaks the loop and stops looking
    for more xattr items
      --> the application doesn't get any xattr
          listed for our inode

So fix this by breaking the loop only if the key's type is greater than
BTRFS_XATTR_ITEM_KEY and skip the current key if its type is smaller.

Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-09 18:34:40 +00:00
Filipe Manana
1d512cb77b Btrfs: fix race leading to BUG_ON when running delalloc for nodatacow
If we are using the NO_HOLES feature, we have a tiny time window when
running delalloc for a nodatacow inode where we can race with a concurrent
link or xattr add operation leading to a BUG_ON.

This happens because at run_delalloc_nocow() we end up casting a leaf item
of type BTRFS_INODE_[REF|EXTREF]_KEY or of type BTRFS_XATTR_ITEM_KEY to a
file extent item (struct btrfs_file_extent_item) and then analyse its
extent type field, which won't match any of the expected extent types
(values BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]) and therefore trigger an
explicit BUG_ON(1).

The following sequence diagram shows how the race happens when running a
no-cow dellaloc range [4K, 8K[ for inode 257 and we have the following
neighbour leafs:

             Leaf X (has N items)                    Leaf Y

 [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ]  [ (257 EXTENT_DATA 8192), ... ]
              slot N - 2         slot N - 1              slot 0

 (Note the implicit hole for inode 257 regarding the [0, 8K[ range)

       CPU 1                                         CPU 2

 run_dealloc_nocow()
   btrfs_lookup_file_extent()
     --> searches for a key with value
         (257 EXTENT_DATA 4096) in the
         fs/subvol tree
     --> returns us a path with
         path->nodes[0] == leaf X and
         path->slots[0] == N

   because path->slots[0] is >=
   btrfs_header_nritems(leaf X), it
   calls btrfs_next_leaf()

   btrfs_next_leaf()
     --> releases the path

                                              hard link added to our inode,
                                              with key (257 INODE_REF 500)
                                              added to the end of leaf X,
                                              so leaf X now has N + 1 keys

     --> searches for the key
         (257 INODE_REF 256), because
         it was the last key in leaf X
         before it released the path,
         with path->keep_locks set to 1

     --> ends up at leaf X again and
         it verifies that the key
         (257 INODE_REF 256) is no longer
         the last key in the leaf, so it
         returns with path->nodes[0] ==
         leaf X and path->slots[0] == N,
         pointing to the new item with
         key (257 INODE_REF 500)

   the loop iteration of run_dealloc_nocow()
   does not break out the loop and continues
   because the key referenced in the path
   at path->nodes[0] and path->slots[0] is
   for inode 257, its type is < BTRFS_EXTENT_DATA_KEY
   and its offset (500) is less then our delalloc
   range's end (8192)

   the item pointed by the path, an inode reference item,
   is (incorrectly) interpreted as a file extent item and
   we get an invalid extent type, leading to the BUG_ON(1):

   if (extent_type == BTRFS_FILE_EXTENT_REG ||
      extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
       (...)
   } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
       (...)
   } else {
       BUG_ON(1)
   }

The same can happen if a xattr is added concurrently and ends up having
a key with an offset smaller then the delalloc's range end.

So fix this by skipping keys with a type smaller than
BTRFS_EXTENT_DATA_KEY.

Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-09 11:29:14 +00:00
Filipe Manana
aeafbf8486 Btrfs: fix race leading to incorrect item deletion when dropping extents
While running a stress test I got the following warning triggered:

  [191627.672810] ------------[ cut here ]------------
  [191627.673949] WARNING: CPU: 8 PID: 8447 at fs/btrfs/file.c:779 __btrfs_drop_extents+0x391/0xa50 [btrfs]()
  (...)
  [191627.701485] Call Trace:
  [191627.702037]  [<ffffffff8145f077>] dump_stack+0x4f/0x7b
  [191627.702992]  [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2
  [191627.704091]  [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
  [191627.705380]  [<ffffffffa0664499>] ? __btrfs_drop_extents+0x391/0xa50 [btrfs]
  [191627.706637]  [<ffffffff8104b46d>] warn_slowpath_null+0x1a/0x1c
  [191627.707789]  [<ffffffffa0664499>] __btrfs_drop_extents+0x391/0xa50 [btrfs]
  [191627.709155]  [<ffffffff8115663c>] ? cache_alloc_debugcheck_after.isra.32+0x171/0x1d0
  [191627.712444]  [<ffffffff81155007>] ? kmemleak_alloc_recursive.constprop.40+0x16/0x18
  [191627.714162]  [<ffffffffa06570c9>] insert_reserved_file_extent.constprop.40+0x83/0x24e [btrfs]
  [191627.715887]  [<ffffffffa065422b>] ? start_transaction+0x3bb/0x610 [btrfs]
  [191627.717287]  [<ffffffffa065b604>] btrfs_finish_ordered_io+0x273/0x4e2 [btrfs]
  [191627.728865]  [<ffffffffa065b888>] finish_ordered_fn+0x15/0x17 [btrfs]
  [191627.730045]  [<ffffffffa067d688>] normal_work_helper+0x14c/0x32c [btrfs]
  [191627.731256]  [<ffffffffa067d96a>] btrfs_endio_write_helper+0x12/0x14 [btrfs]
  [191627.732661]  [<ffffffff81061119>] process_one_work+0x24c/0x4ae
  [191627.733822]  [<ffffffff810615b0>] worker_thread+0x206/0x2c2
  [191627.734857]  [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f
  [191627.736052]  [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f
  [191627.737349]  [<ffffffff810669a6>] kthread+0xef/0xf7
  [191627.738267]  [<ffffffff810f3b3a>] ? time_hardirqs_on+0x15/0x28
  [191627.739330]  [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad
  [191627.741976]  [<ffffffff81465592>] ret_from_fork+0x42/0x70
  [191627.743080]  [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad
  [191627.744206] ---[ end trace bbfddacb7aaada8d ]---

  $ cat -n fs/btrfs/file.c
  691  int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
  (...)
  758                  btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
  759                  if (key.objectid > ino ||
  760                      key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
  761                          break;
  762
  763                  fi = btrfs_item_ptr(leaf, path->slots[0],
  764                                      struct btrfs_file_extent_item);
  765                  extent_type = btrfs_file_extent_type(leaf, fi);
  766
  767                  if (extent_type == BTRFS_FILE_EXTENT_REG ||
  768                      extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
  (...)
  774                  } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
  (...)
  778                  } else {
  779                          WARN_ON(1);
  780                          extent_end = search_start;
  781                  }
  (...)

This happened because the item we were processing did not match a file
extent item (its key type != BTRFS_EXTENT_DATA_KEY), and even on this
case we cast the item to a struct btrfs_file_extent_item pointer and
then find a type field value that does not match any of the expected
values (BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]). This scenario happens
due to a tiny time window where a race can happen as exemplified below.
For example, consider the following scenario where we're using the
NO_HOLES feature and we have the following two neighbour leafs:

               Leaf X (has N items)                    Leaf Y

[ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ]  [ (257 EXTENT_DATA 8192), ... ]
          slot N - 2         slot N - 1              slot 0

Our inode 257 has an implicit hole in the range [0, 8K[ (implicit rather
than explicit because NO_HOLES is enabled). Now if our inode has an
ordered extent for the range [4K, 8K[ that is finishing, the following
can happen:

          CPU 1                                       CPU 2

  btrfs_finish_ordered_io()
    insert_reserved_file_extent()
      __btrfs_drop_extents()
         Searches for the key
          (257 EXTENT_DATA 4096) through
          btrfs_lookup_file_extent()

         Key not found and we get a path where
         path->nodes[0] == leaf X and
         path->slots[0] == N

         Because path->slots[0] is >=
         btrfs_header_nritems(leaf X), we call
         btrfs_next_leaf()

         btrfs_next_leaf() releases the path

                                                  inserts key
                                                  (257 INODE_REF 4096)
                                                  at the end of leaf X,
                                                  leaf X now has N + 1 keys,
                                                  and the new key is at
                                                  slot N

         btrfs_next_leaf() searches for
         key (257 INODE_REF 256), with
         path->keep_locks set to 1,
         because it was the last key it
         saw in leaf X

           finds it in leaf X again and
           notices it's no longer the last
           key of the leaf, so it returns 0
           with path->nodes[0] == leaf X and
           path->slots[0] == N (which is now
           < btrfs_header_nritems(leaf X)),
           pointing to the new key
           (257 INODE_REF 4096)

         __btrfs_drop_extents() casts the
         item at path->nodes[0], slot
         path->slots[0], to a struct
         btrfs_file_extent_item - it does
         not skip keys for the target
         inode with a type less than
         BTRFS_EXTENT_DATA_KEY
         (BTRFS_INODE_REF_KEY < BTRFS_EXTENT_DATA_KEY)

         sees a bogus value for the type
         field triggering the WARN_ON in
         the trace shown above, and sets
         extent_end = search_start (4096)

         does the if-then-else logic to
         fixup 0 length extent items created
         by a past bug from hole punching:

           if (extent_end == key.offset &&
               extent_end >= search_start)
               goto delete_extent_item;

         that evaluates to true and it ends
         up deleting the key pointed to by
         path->slots[0], (257 INODE_REF 4096),
         from leaf X

The same could happen for example for a xattr that ends up having a key
with an offset value that matches search_start (very unlikely but not
impossible).

So fix this by ensuring that keys smaller than BTRFS_EXTENT_DATA_KEY are
skipped, never casted to struct btrfs_file_extent_item and never deleted
by accident. Also protect against the unexpected case of getting a key
for a lower inode number by skipping that key and issuing a warning.

Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-08 21:51:28 +00:00
Linus Torvalds
ad804a0b2a Merge branch 'akpm' (patches from Andrew)
Merge second patch-bomb from Andrew Morton:

 - most of the rest of MM

 - procfs

 - lib/ updates

 - printk updates

 - bitops infrastructure tweaks

 - checkpatch updates

 - nilfs2 update

 - signals

 - various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
   dma-debug, dma-mapping, ...

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits)
  ipc,msg: drop dst nil validation in copy_msg
  include/linux/zutil.h: fix usage example of zlib_adler32()
  panic: release stale console lock to always get the logbuf printed out
  dma-debug: check nents in dma_sync_sg*
  dma-mapping: tidy up dma_parms default handling
  pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
  kexec: use file name as the output message prefix
  fs, seqfile: always allow oom killer
  seq_file: reuse string_escape_str()
  fs/seq_file: use seq_* helpers in seq_hex_dump()
  coredump: change zap_threads() and zap_process() to use for_each_thread()
  coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
  signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)
  signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
  signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
  signals: kill block_all_signals() and unblock_all_signals()
  nilfs2: fix gcc uninitialized-variable warnings in powerpc build
  nilfs2: fix gcc unused-but-set-variable warnings
  MAINTAINERS: nilfs2: add header file for tracing
  nilfs2: add tracepoints for analyzing reading and writing metadata files
  ...
2015-11-07 14:32:45 -08:00
Michal Hocko
c62d25556b mm, fs: introduce mapping_gfp_constraint()
There are many places which use mapping_gfp_mask to restrict a more
generic gfp mask which would be used for allocations which are not
directly related to the page cache but they are performed in the same
context.

Let's introduce a helper function which makes the restriction explicit and
easier to track.  This patch doesn't introduce any functional changes.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Mel Gorman
d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Linus Torvalds
27eb427bdc Merge branch 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
 "We have a lot of subvolume quota improvements in here, along with big
  piles of cleanups from Dave Sterba and Anand Jain and others.

  Josef pitched in a batch of allocator fixes based on production use
  here at FB.  We found that mount -o ssd_spread greatly improved our
  performance on hardware raid5/6, but it exposed some CPU bottlenecks
  in the allocator.  These patches make a huge difference"

* 'for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (100 commits)
  Btrfs: fix hole punching when using the no-holes feature
  Btrfs: find_free_extent: Do not erroneously skip LOOP_CACHING_WAIT state
  btrfs: Fix a data space underflow warning
  btrfs: qgroup: Fix a rebase bug which will cause qgroup double free
  btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans
  btrfs: clear PF_NOFREEZE in cleaner_kthread()
  btrfs: qgroup: Don't copy extent buffer to do qgroup rescan
  btrfs: add balance filters limits, stripes and usage to supported mask
  btrfs: extend balance filter usage to take minimum and maximum
  btrfs: add balance filter for stripes
  btrfs: extend balance filter limit to take minimum and maximum
  btrfs: fix use after free iterating extrefs
  btrfs: check unsupported filters in balance arguments
  Btrfs: fix regression running delayed references when using qgroups
  Btrfs: fix regression when running delayed references
  Btrfs: don't do extra bitmap search in one bit case
  Btrfs: keep track of largest extent in bitmaps
  Btrfs: don't keep trying to build clusters if we are fragmented
  Btrfs: cut down on loops through the allocator
  Btrfs: don't continue setting up space cache when enospc
  ...
2015-11-06 17:17:13 -08:00
Filipe Manana
3b2ba7b31d Btrfs: fix sleeping inside atomic context in qgroup rescan worker
We are holding a btree path with spinning locks and then we attempt to
clone an extent buffer, which calls kmem_cache_alloc() and this function
can sleep, causing the following trace to be reported on a debug kernel:

[107118.218536] BUG: sleeping function called from invalid context at mm/slab.c:2871
[107118.224110] in_atomic(): 1, irqs_disabled(): 0, pid: 19148, name: kworker/u32:3
[107118.226120] INFO: lockdep is turned off.
[107118.226843] Preemption disabled at:[<ffffffffa05ffa22>] btrfs_clear_lock_blocking_rw+0x96/0xea [btrfs]

[107118.229175] CPU: 3 PID: 19148 Comm: kworker/u32:3 Tainted: G        W       4.3.0-rc5-btrfs-next-17+ #1
[107118.231326] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[107118.233687] Workqueue: btrfs-qgroup-rescan btrfs_qgroup_rescan_helper [btrfs]
[107118.236835]  0000000000000000 ffff880424bf3b78 ffffffff812566f4 0000000000000000
[107118.238369]  ffff880424bf3ba0 ffffffff81070664 ffffffff817f1cd5 0000000000000b37
[107118.239769]  0000000000000000 ffff880424bf3bc8 ffffffff8107070a 0000000000008850
[107118.241244] Call Trace:
[107118.241729]  [<ffffffff812566f4>] dump_stack+0x4e/0x79
[107118.242602]  [<ffffffff81070664>] ___might_sleep+0x23a/0x241
[107118.243586]  [<ffffffff8107070a>] __might_sleep+0x9f/0xa6
[107118.244532]  [<ffffffff8115af70>] cache_alloc_debugcheck_before+0x25/0x36
[107118.245939]  [<ffffffff8115d52b>] kmem_cache_alloc+0x50/0x215
[107118.246930]  [<ffffffffa05e627e>] __alloc_extent_buffer+0x2a/0x11f [btrfs]
[107118.248121]  [<ffffffffa05ecb1a>] btrfs_clone_extent_buffer+0x3d/0xdd [btrfs]
[107118.249451]  [<ffffffffa06239ea>] btrfs_qgroup_rescan_worker+0x16d/0x434 [btrfs]
[107118.250755]  [<ffffffff81087481>] ? arch_local_irq_save+0x9/0xc
[107118.251754]  [<ffffffffa05f7952>] normal_work_helper+0x14c/0x32a [btrfs]
[107118.252899]  [<ffffffffa05f7952>] ? normal_work_helper+0x14c/0x32a [btrfs]
[107118.254195]  [<ffffffffa05f7c82>] btrfs_qgroup_rescan_helper+0x12/0x14 [btrfs]
[107118.255436]  [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
[107118.263690]  [<ffffffff81064285>] worker_thread+0x206/0x2c2
[107118.264888]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[107118.267413]  [<ffffffff8106904d>] kthread+0xef/0xf7
[107118.268417]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[107118.269505]  [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
[107118.270491]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24

So just use blocking locks for our path to solve this.
This fixes the patch titled:
  "btrfs: qgroup: Don't copy extent buffer to do qgroup rescan"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-05 11:02:22 +00:00
Filipe Manana
190631f1c8 Btrfs: fix race waiting for qgroup rescan worker
We were initializing the completion (fs_info->qgroup_rescan_completion)
object after releasing the qgroup rescan lock, which gives a small time
window for a rescan waiter to not actually wait for the rescan worker
to finish. Example:

         CPU 1                                                     CPU 2

 fs_info->qgroup_rescan_completion->done is 0

 btrfs_qgroup_rescan_worker()
   complete_all(&fs_info->qgroup_rescan_completion)
     sets fs_info->qgroup_rescan_completion->done
     to UINT_MAX / 2

 ... do some other stuff ....

 qgroup_rescan_init()
   mutex_lock(&fs_info->qgroup_rescan_lock)
   set flag BTRFS_QGROUP_STATUS_FLAG_RESCAN
     in fs_info->qgroup_flags
   mutex_unlock(&fs_info->qgroup_rescan_lock)

                                                       btrfs_qgroup_wait_for_completion()
                                                         mutex_lock(&fs_info->qgroup_rescan_lock)
                                                         sees flag BTRFS_QGROUP_STATUS_FLAG_RESCAN
                                                           in fs_info->qgroup_flags
                                                         mutex_unlock(&fs_info->qgroup_rescan_lock)

                                                         wait_for_completion_interruptible(
                                                           &fs_info->qgroup_rescan_completion)

                                                           fs_info->qgroup_rescan_completion->done
                                                           is > 0 so it returns immediately

  init_completion(&fs_info->qgroup_rescan_completion)
    sets fs_info->qgroup_rescan_completion->done to 0

So fix this by initializing the completion object while holding the mutex
fs_info->qgroup_rescan_lock.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-05 10:32:21 +00:00
Justin Maggard
7343dd61fd btrfs: qgroup: exit the rescan worker during umount
I was hitting a consistent NULL pointer dereference during shutdown that
showed the trace running through end_workqueue_bio().  I traced it back to
the endio_meta_workers workqueue being poked after it had already been
destroyed.

Eventually I found that the root cause was a qgroup rescan that was still
in progress while we were stopping all the btrfs workers.

Currently we explicitly pause balance and scrub operations in
close_ctree(), but we do nothing to stop the qgroup rescan.  We should
probably be doing the same for qgroup rescan, but that's a much larger
change.  This small change is good enough to allow me to unmount without
crashing.

Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
2015-11-05 10:32:20 +00:00
Filipe Manana
9c9464cc92 Btrfs: fix extent accounting for partial direct IO writes
When doing a write using direct IO we can end up not doing the whole write
operation using the direct IO path, in that case we fallback to a buffered
write to do the remaining IO. This happens for example if the range we are
writing to contains a compressed extent.
When we do a partial write and fallback to buffered IO, due to the
existence of a compressed extent for example, we end up not adjusting the
outstanding extents counter of our inode which ends up getting decremented
twice, once by the DIO ordered extent for the partial write and once again
by btrfs_direct_IO(), resulting in an arithmetic underflow at
extent-tree.c:drop_outstanding_extent(). For example if we have:

  extents        [ prealloc extent ] [ compressed extent ]
  offsets        A        B          C       D           E

and at the moment our inode's outstanding extents counter is 0, if we do a
direct IO write against the range [B, D[ (which has a length smaller than
128Mb), we end up bumping our inode's outstanding extents counter to 1, we
create a DIO ordered extent for the range [B, C[ and then fallback to a
buffered write for the range [C, D[. The direct IO handler
(inode.c:btrfs_direct_IO()) decrements the outstanding extents counter by
1, leaving it with a value of 0, through a call to
btrfs_delalloc_release_space() and then shortly after the DIO ordered
extent finishes and calls btrfs_delalloc_release_metadata() which ends
up to attempt to decrement the inode's outstanding extents counter by 1,
resulting in an assertion failure at drop_outstanding_extent() because
the operation would result in an arithmetic underflow (0 - 1). This
produces the following trace:

  [125471.336838] BTRFS: assertion failed: BTRFS_I(inode)->outstanding_extents >= num_extents, file: fs/btrfs/extent-tree.c, line: 5526
  [125471.338844] ------------[ cut here ]------------
  [125471.340745] kernel BUG at fs/btrfs/ctree.h:4173!
  [125471.340745] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  [125471.340745] Modules linked in: btrfs f2fs xfs libcrc32c dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc acpi_cpufreq psmouse i2c_piix4 parport pcspkr serio_raw microcode processor evdev i2c_core button ext4 crc16 jbd2 mbcache sd_mod sg sr_mod cdrom ata_generic virtio_scsi ata_piix virtio_pci virtio_ring floppy libata virtio e1000 scsi_mod [last unloaded: btrfs]
  [125471.340745] CPU: 10 PID: 23649 Comm: kworker/u32:1 Tainted: G        W       4.3.0-rc5-btrfs-next-17+ #1
  [125471.340745] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
  [125471.340745] Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
  [125471.340745] task: ffff8804244fcf80 ti: ffff88040a118000 task.ti: ffff88040a118000
  [125471.340745] RIP: 0010:[<ffffffffa0550da1>]  [<ffffffffa0550da1>] assfail.constprop.46+0x1e/0x20 [btrfs]
  [125471.340745] RSP: 0018:ffff88040a11bc78  EFLAGS: 00010296
  [125471.340745] RAX: 0000000000000075 RBX: 0000000000005000 RCX: 0000000000000000
  [125471.340745] RDX: ffffffff81098f93 RSI: ffffffff8147c619 RDI: 00000000ffffffff
  [125471.340745] RBP: ffff88040a11bc78 R08: 0000000000000001 R09: 0000000000000000
  [125471.340745] R10: ffff88040a11bc08 R11: ffffffff81651000 R12: ffff8803efb4a000
  [125471.340745] R13: ffff8803efb4a000 R14: 0000000000000000 R15: ffff8802f8e33c88
  [125471.340745] FS:  0000000000000000(0000) GS:ffff88043dd40000(0000) knlGS:0000000000000000
  [125471.340745] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  [125471.340745] CR2: 00007fae7ca86095 CR3: 0000000001a0b000 CR4: 00000000000006e0
  [125471.340745] Stack:
  [125471.340745]  ffff88040a11bc88 ffffffffa04ca0cd ffff88040a11bcc8 ffffffffa04ceeb1
  [125471.340745]  ffff8802f8e33940 ffff8802c93eadb0 ffff8802f8e0bf50 ffff8803efb4a000
  [125471.340745]  0000000000000000 ffff8802f8e33c88 ffff88040a11bd38 ffffffffa04eccfa
  [125471.340745] Call Trace:
  [125471.340745]  [<ffffffffa04ca0cd>] drop_outstanding_extent+0x3d/0x6d [btrfs]
  [125471.340745]  [<ffffffffa04ceeb1>] btrfs_delalloc_release_metadata+0x51/0xdd [btrfs]
  [125471.340745]  [<ffffffffa04eccfa>] btrfs_finish_ordered_io+0x420/0x4eb [btrfs]
  [125471.340745]  [<ffffffffa04ecdda>] finish_ordered_fn+0x15/0x17 [btrfs]
  [125471.340745]  [<ffffffffa050e6e8>] normal_work_helper+0x14c/0x32a [btrfs]
  [125471.340745]  [<ffffffffa050e9c8>] btrfs_endio_write_helper+0x12/0x14 [btrfs]
  [125471.340745]  [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
  [125471.340745]  [<ffffffff81064285>] worker_thread+0x206/0x2c2
  [125471.340745]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
  [125471.340745]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
  [125471.340745]  [<ffffffff8106904d>] kthread+0xef/0xf7
  [125471.340745]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
  [125471.340745]  [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
  [125471.340745]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
  [125471.340745] Code: a5 55 a0 48 89 e5 e8 42 50 bc e0 0f 0b 55 89 f1 48 c7 c2 f0 a8 55 a0 48 89 fe 31 c0 48 c7 c7 14 aa 55 a0 48 89 e5 e8 22 50 bc e0 <0f> 0b 0f 1f 44 00 00 55 31 c9 ba 18 00 00 00 48 89 e5 41 56 41
  [125471.340745] RIP  [<ffffffffa0550da1>] assfail.constprop.46+0x1e/0x20 [btrfs]
  [125471.340745]  RSP <ffff88040a11bc78>
  [125471.539620] ---[ end trace 144259f7838b4aa4 ]---

So fix this by ensuring we adjust the outstanding extents counter when we
do the fallback just like we do for the case where the whole write can be
done through the direct IO path.

We were also adjusting the outstanding extents counter by a constant value
of 1, which is incorrect because we were ignorning that we account extents
in BTRFS_MAX_EXTENT_SIZE units, o fix that as well.

The following test case for fstests reproduces this issue:

  seq=`basename $0`
  seqres=$RESULT_DIR/$seq
  echo "QA output created by $seq"
  tmp=/tmp/$$
  status=1	# failure is the default!
  trap "_cleanup; exit \$status" 0 1 2 3 15

  _cleanup()
  {
      rm -f $tmp.*
  }

  # get standard environment, filters and checks
  . ./common/rc
  . ./common/filter

  # real QA test starts here
  _need_to_be_root
  _supported_fs btrfs
  _supported_os Linux
  _require_scratch
  _require_xfs_io_command "falloc"

  rm -f $seqres.full

  _scratch_mkfs >>$seqres.full 2>&1
  _scratch_mount "-o compress"

  # Create a compressed extent covering the range [700K, 800K[.
  $XFS_IO_PROG -f -s -c "pwrite -S 0xaa -b 100K 700K 100K" \
      $SCRATCH_MNT/foo | _filter_xfs_io

  # Create prealloc extent covering the range [600K, 700K[.
  $XFS_IO_PROG -c "falloc 600K 100K" $SCRATCH_MNT/foo

  # Write 80K of data to the range [640K, 720K[ using direct IO. This
  # range covers both the prealloc extent and the compressed extent.
  # Because there's a compressed extent in the range we are writing to,
  # the DIO write code path ends up only writing the first 60k of data,
  # which goes to the prealloc extent, and then falls back to buffered IO
  # for writing the remaining 20K of data - because that remaining data
  # maps to a file range containing a compressed extent.
  # When falling back to buffered IO, we used to trigger an assertion when
  # releasing reserved space due to bad accounting of the inode's
  # outstanding extents counter, which was set to 1 but we ended up
  # decrementing it by 1 twice, once through the ordered extent for the
  # 60K of data we wrote using direct IO, and once through the main direct
  # IO handler (inode.cbtrfs_direct_IO()) because the direct IO write
  # wrote less than 80K of data (60K).
  $XFS_IO_PROG -d -c "pwrite -S 0xbb -b 80K 640K 80K" \
      $SCRATCH_MNT/foo | _filter_xfs_io

  # Now similar test as above but for very large write operations. This
  # triggers special cases for an inode's outstanding extents accounting,
  # as internally btrfs logically splits extents into 128Mb units.
  $XFS_IO_PROG -f -s \
      -c "pwrite -S 0xaa -b 128M 258M 128M" \
      -c "falloc 0 258M" \
      $SCRATCH_MNT/bar | _filter_xfs_io
  $XFS_IO_PROG -d -c "pwrite -S 0xbb -b 256M 3M 256M" $SCRATCH_MNT/bar \
      | _filter_xfs_io

  # Now verify the file contents are correct and that they are the same
  # even after unmounting and mounting the fs again (or evicting the page
  # cache).
  #
  # For file foo, all bytes in the range [0, 640K[ must have a value of
  # 0x00, all bytes in the range [640K, 720K[ must have a value of 0xbb
  # and all bytes in the range [720K, 800K[ must have a value of 0xaa.
  #
  # For file bar, all bytes in the range [0, 3M[ must havea value of 0x00,
  # all bytes in the range [3M, 259M[ must have a value of 0xbb and all
  # bytes in the range [259M, 386M[ must have a value of 0xaa.
  #
  echo "File digests before remounting the file system:"
  md5sum $SCRATCH_MNT/foo | _filter_scratch
  md5sum $SCRATCH_MNT/bar | _filter_scratch
  _scratch_remount
  echo "File digests after remounting the file system:"
  md5sum $SCRATCH_MNT/foo | _filter_scratch
  md5sum $SCRATCH_MNT/bar | _filter_scratch

  status=0
  exit

Fixes: e1cbbfa5f5 ("Btrfs: fix outstanding_extents accounting in DIO")
Fixes: 3e05bde8c3 ("Btrfs: only adjust outstanding_extents when we do a short write")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
2015-11-05 10:32:19 +00:00
Filipe Manana
2959a32a85 Btrfs: fix hole punching when using the no-holes feature
When we are using the no-holes feature, if we punch a hole into a file
range that already contains a hole which overlaps the range we are passing
to fallocate(), we end up removing the extent map that represents the
existing hole without adding a new one. This happens because with the
no-holes feature we do not have explicit extent items to represent holes
and therefore the call to __btrfs_drop_extents(), made from
btrfs_punch_hole(), returns an end offset to the variable drop_end that
is smaller than the end of the range passed to fallocate(), while it
drops all existing extent maps in that range.
Normally having a missing extent map is not a problem, for example for
a readpages() operation we just end up building the extent map by
looking at the fs/subvol tree for a matching extent item (or a lack of
one for implicit holes). However for an fsync that uses the fast path,
which needs to look at the list of modified extent maps, this means
the fsync will not record information about the complete hole we had
before the fallocate() call into the log tree, resulting in a file with
content/layout that does not match what we had neither before nor after
the hole punch operation.

The following test case for fstests reproduces the issue. It fails without
this change because we get a file with a different digest after the fsync
log replay and also with a different extent/hole layout.

  seq=`basename $0`
  seqres=$RESULT_DIR/$seq
  echo "QA output created by $seq"
  tmp=/tmp/$$
  status=1	# failure is the default!
  trap "_cleanup; exit \$status" 0 1 2 3 15

  _cleanup()
  {
     _cleanup_flakey
     rm -f $tmp.*
  }

  # get standard environment, filters and checks
  . ./common/rc
  . ./common/filter
  . ./common/punch
  . ./common/dmflakey

  # real QA test starts here
  _need_to_be_root
  _supported_fs generic
  _supported_os Linux
  _require_scratch
  _require_xfs_io_command "fpunch"
  _require_xfs_io_command "fiemap"
  _require_dm_target flakey
  _require_metadata_journaling $SCRATCH_DEV

  # This test was motivated by an issue found in btrfs when the btrfs
  # no-holes feature is enabled (introduced in kernel 3.14). So enable
  # the feature if the fs being tested is btrfs.
  if [ $FSTYP == "btrfs" ]; then
      _require_btrfs_fs_feature "no_holes"
      _require_btrfs_mkfs_feature "no-holes"
      MKFS_OPTIONS="$MKFS_OPTIONS -O no-holes"
  fi

  rm -f $seqres.full

  _scratch_mkfs >>$seqres.full 2>&1
  _init_flakey
  _mount_flakey

  # Create out test file with some data and then fsync it.
  # We do the fsync only to make sure the last fsync we do in this test
  # triggers the fast code path of btrfs' fsync implementation, a
  # condition necessary to trigger the bug btrfs had.
  $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 128K" \
                  -c "fsync"                  \
                  $SCRATCH_MNT/foobar | _filter_xfs_io

  # Now punch a hole against the range [96K, 128K[.
  $XFS_IO_PROG -c "fpunch 96K 32K" $SCRATCH_MNT/foobar

  # Punch another hole against a range that overlaps the previous range
  # and ends beyond eof.
  $XFS_IO_PROG -c "fpunch 64K 128K" $SCRATCH_MNT/foobar

  # Punch another hole against a range that overlaps the first range
  # ([96K, 128K[) and ends at eof.
  $XFS_IO_PROG -c "fpunch 32K 96K" $SCRATCH_MNT/foobar

  # Fsync our file. We want to verify that, after a power failure and
  # mounting the filesystem again, the file content reflects all the hole
  # punch operations.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar

  echo "File digest before power failure:"
  md5sum $SCRATCH_MNT/foobar | _filter_scratch

  echo "Fiemap before power failure:"
  $XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar | _filter_fiemap

  # Silently drop all writes and umount to simulate a crash/power failure.
  _load_flakey_table $FLAKEY_DROP_WRITES
  _unmount_flakey

  # Allow writes again, mount to trigger log replay and validate file
  # contents.
  _load_flakey_table $FLAKEY_ALLOW_WRITES
  _mount_flakey

  echo "File digest after log replay:"
  # Must match the same digest we got before the power failure.
  md5sum $SCRATCH_MNT/foobar | _filter_scratch

  echo "Fiemap after log replay:"
  # Must match the same extent listing we got before the power failure.
  $XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar | _filter_fiemap

  _unmount_flakey

  status=0
  exit

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-03 07:44:20 -08:00
chandan
13a0db5a53 Btrfs: find_free_extent: Do not erroneously skip LOOP_CACHING_WAIT state
When executing generic/001 in a loop on a ppc64 machine (with both sectorsize
and nodesize set to 64k), the following call trace is observed,

WARNING: at /root/repos/linux/fs/btrfs/locking.c:253
Modules linked in:
CPU: 2 PID: 8353 Comm: umount Not tainted 4.3.0-rc5-13676-ga5e681d #54
task: c0000000f2b1f560 ti: c0000000f6008000 task.ti: c0000000f6008000
NIP: c000000000520c88 LR: c0000000004a3b34 CTR: 0000000000000000
REGS: c0000000f600a820 TRAP: 0700   Not tainted  (4.3.0-rc5-13676-ga5e681d)
MSR: 8000000102029032 <SF,VEC,EE,ME,IR,DR,RI>  CR: 24444884  XER: 00000000
CFAR: c0000000004a3b30 SOFTE: 1
GPR00: c0000000004a3b34 c0000000f600aaa0 c00000000108ac00 c0000000f5a808c0
GPR04: 0000000000000000 c0000000f600ae60 0000000000000000 0000000000000005
GPR08: 00000000000020a1 0000000000000001 c0000000f2b1f560 0000000000000030
GPR12: 0000000084842882 c00000000fdc0900 c0000000f600ae60 c0000000f070b800
GPR16: 0000000000000000 c0000000f3c8a000 0000000000000000 0000000000000049
GPR20: 0000000000000001 0000000000000001 c0000000f5aa01f8 0000000000000000
GPR24: 0f83e0f83e0f83e1 c0000000f5a808c0 c0000000f3c8d000 c000000000000000
GPR28: c0000000f600ae74 0000000000000001 c0000000f3c8d000 c0000000f5a808c0
NIP [c000000000520c88] .btrfs_tree_lock+0x48/0x2a0
LR [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
Call Trace:
[c0000000f600aaa0] [c0000000f600ab80] 0xc0000000f600ab80 (unreliable)
[c0000000f600ab80] [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
[c0000000f600ac00] [c0000000004a99dc] .btrfs_search_slot+0xa8c/0xc00
[c0000000f600ad40] [c0000000004ab878] .btrfs_insert_empty_items+0x98/0x120
[c0000000f600adf0] [c00000000050da44] .btrfs_finish_chunk_alloc+0x1d4/0x620
[c0000000f600af20] [c0000000004be854] .btrfs_create_pending_block_groups+0x1d4/0x2c0
[c0000000f600b020] [c0000000004bf188] .do_chunk_alloc+0x3c8/0x420
[c0000000f600b100] [c0000000004c27cc] .find_free_extent+0xbfc/0x1030
[c0000000f600b260] [c0000000004c2ce8] .btrfs_reserve_extent+0xe8/0x250
[c0000000f600b330] [c0000000004c2f90] .btrfs_alloc_tree_block+0x140/0x590
[c0000000f600b440] [c0000000004a47b4] .__btrfs_cow_block+0x124/0x780
[c0000000f600b530] [c0000000004a4fc0] .btrfs_cow_block+0xf0/0x250
[c0000000f600b5e0] [c0000000004a917c] .btrfs_search_slot+0x22c/0xc00
[c0000000f600b720] [c00000000050aa40] .btrfs_remove_chunk+0x1b0/0x9f0
[c0000000f600b850] [c0000000004c4e04] .btrfs_delete_unused_bgs+0x434/0x570
[c0000000f600b950] [c0000000004d3cb8] .close_ctree+0x2e8/0x3b0
[c0000000f600ba20] [c00000000049d178] .btrfs_put_super+0x18/0x30
[c0000000f600ba90] [c000000000243cd4] .generic_shutdown_super+0xa4/0x1a0
[c0000000f600bb10] [c0000000002441d8] .kill_anon_super+0x18/0x30
[c0000000f600bb90] [c00000000049c898] .btrfs_kill_super+0x18/0xc0
[c0000000f600bc10] [c0000000002444f8] .deactivate_locked_super+0x98/0xe0
[c0000000f600bc90] [c000000000269f94] .cleanup_mnt+0x54/0xa0
[c0000000f600bd10] [c0000000000bd744] .task_work_run+0xc4/0x100
[c0000000f600bdb0] [c000000000016334] .do_notify_resume+0x74/0x80
[c0000000f600be30] [c0000000000098b8] .ret_from_except_lite+0x64/0x68
Instruction dump:
fba1ffe8 fbc1fff0 fbe1fff8 7c791b78 f8010010 f821ff21 e94d0290 81030040
812a04e8 7d094a78 7d290034 5529d97e <0b090000> 3b400000 3be30050 3bc3004c

The above call trace is seen even on x86_64; albeit very rarely and that too
with nodesize set to 64k and with nospace_cache mount option being used.

The reason for the above call trace is,
btrfs_remove_chunk
  check_system_chunk
    Allocate chunk if required
  For each physical stripe on underlying device,
    btrfs_free_dev_extent
      ...
      Take lock on Device tree's root node
      btrfs_cow_block("dev tree's root node");
        btrfs_reserve_extent
          find_free_extent
	    index = BTRFS_RAID_DUP;
	    have_caching_bg = false;

            When in LOOP_CACHING_NOWAIT state, Assume we find a block group
	    which is being cached; Hence have_caching_bg is set to true

            When repeating the search for the next RAID index, we set
	    have_caching_bg to false.

Hence right after completing the LOOP_CACHING_NOWAIT state, we incorrectly
skip LOOP_CACHING_WAIT state and move to LOOP_ALLOC_CHUNK state where we
allocate a chunk and try to add entries corresponding to the chunk's physical
stripe into the device tree. When doing so the task deadlocks itself waiting
for the blocking lock on the root node of the device tree.

This commit fixes the issue by introducing a new local variable to help
indicate as to whether a block group of any RAID type is being cached.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-03 07:44:20 -08:00
Qu Wenruo
485290a734 btrfs: Fix a data space underflow warning
Even with quota disabled, generic/127 will trigger a kernel warning by
underflow data space info.

The bug is caused by buffered write, which in case of short copy, the
start parameter for btrfs_delalloc_release_space() is wrong, and
round_up/down() in btrfs_delalloc_release() extents the range to page
aligned, decreasing one more page than expected.

This patch will fix it by passing correct start.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-11-03 07:44:20 -08:00
Qu Wenruo
90ce321da8 btrfs: qgroup: Fix a rebase bug which will cause qgroup double free
When rebasing my patchset, I forgot to pick up a cleanup patch to remove
old hotfix in 4.2 release.

Witouth the cleanup, it will screw up new qgroup reserve framework and
always cause minus reserved number.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:44:39 -07:00
Qu Wenruo
5846a3c268 btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans
Between btrfs_allocerved_file_extent() and
btrfs_add_delayed_qgroup_reserve(), there is a window that delayed_refs
are run and delayed ref head maybe freed before
btrfs_add_delayed_qgroup_reserve().

This will cause btrfs_dad_delayed_qgroup_reserve() to return -ENOENT,
and cause transaction to be aborted.

This patch will record qgroup reserve space info into delayed_ref_head
at btrfs_add_delayed_ref(), to eliminate the race window.

Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:44:39 -07:00
Jiri Kosina
6962491321 btrfs: clear PF_NOFREEZE in cleaner_kthread()
cleaner_kthread() kthread calls try_to_freeze() at the beginning of every
cleanup attempt. This operation can't ever succeed though, as the kthread
hasn't marked itself as freezable.

Before (hopefully eventually) kthread freezing gets converted to fileystem
freezing, we'd rather mark cleaner_kthread() freezable (as my
understanding is that it can generate filesystem I/O during suspend).

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:42:30 -07:00
Qu Wenruo
0a0e8b8938 btrfs: qgroup: Don't copy extent buffer to do qgroup rescan
Ancient qgroup code call memcpy() on a extent buffer and use it for leaf
iteration.

As extent buffer contains lock, pointers to pages, it's never sane to do
such copy.

The following bug may be caused by this insane operation:
[92098.841309] general protection fault: 0000 [#1] SMP
[92098.841338] Modules linked in: ...
[92098.841814] CPU: 1 PID: 24655 Comm: kworker/u4:12 Not tainted
4.3.0-rc1 #1
[92098.841868] Workqueue: btrfs-qgroup-rescan btrfs_qgroup_rescan_helper
[btrfs]
[92098.842261] Call Trace:
[92098.842277]  [<ffffffffc035a5d8>] ? read_extent_buffer+0xb8/0x110
[btrfs]
[92098.842304]  [<ffffffffc0396d00>] ? btrfs_find_all_roots+0x60/0x70
[btrfs]
[92098.842329]  [<ffffffffc039af3d>]
btrfs_qgroup_rescan_worker+0x28d/0x5a0 [btrfs]

Where btrfs_qgroup_rescan_worker+0x28d is btrfs_disk_key_to_cpu(),
called in reading key from the copied extent_buffer.

This patch will use btrfs_clone_extent_buffer() to a better copy of
extent buffer to deal such case.

Reported-by: Stephane Lesimple <stephane_btrfs@lesimple.fr>
Suggested-by: Filipe Manana <fdmanana@kernel.org>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:42:30 -07:00
David Sterba
b66d62ba1e btrfs: add balance filters limits, stripes and usage to supported mask
Enable the extended 'limit' syntax (a range), the new 'stripes' and
extended 'usage' syntax (a range) filters in the filters mask. The patch
comes separate and not within the series that introduced the new filters
because the patch adding the mask was merged in a late rc. The
integration branch was based on an older rc and could not merge the
patch due to the missing changes.

Prerequisities:
* btrfs: check unsupported filters in balance arguments
* btrfs: extend balance filter limit to take minimum and maximum
* btrfs: add balance filter for stripes
* btrfs: extend balance filter usage to take minimum and maximum

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:30 -07:00
David Sterba
bc3094673f btrfs: extend balance filter usage to take minimum and maximum
Similar to the 'limit' filter, we can enhance the 'usage' filter to
accept a range. The change is backward compatible, the range is applied
only in connection with the BTRFS_BALANCE_ARGS_USAGE_RANGE flag.

We don't have a usecase yet, the current syntax has been sufficient. The
enhancement should provide parity with other range-like filters.

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:30 -07:00
Gabríel Arthúr Pétursson
dee32d0ac3 btrfs: add balance filter for stripes
Balance block groups which have the given number of stripes, defined by
a range min..max. This is useful to selectively rebalance only chunks
that do not span enough devices, applies to RAID0/10/5/6.

Signed-off-by: Gabríel Arthúr Pétursson <gabriel@system.is>
[ renamed bargs members, added to the UAPI, wrote the changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:29 -07:00
David Sterba
12907fc798 btrfs: extend balance filter limit to take minimum and maximum
The 'limit' filter is underdesigned, it should have been a range for
[min,max], with some relaxed semantics when one of the bounds is
missing. Besides that, using a full u64 for a single value is a waste of
bytes.

Let's fix both by extending the use of the u64 bytes for the [min,max]
range. This can be done in a backward compatible way, the range will be
interpreted only if the appropriate flag is set
(BTRFS_BALANCE_ARGS_LIMIT_RANGE).

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:28 -07:00
Chris Mason
2849a85422 btrfs: fix use after free iterating extrefs
The code for btrfs inode-resolve has never worked properly for
files with enough hard links to trigger extrefs.  It was trying to
get the leaf out of a path after freeing the path:

	btrfs_release_path(path);
	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, slot);

The fix here is to use the extent buffer we cloned just a little higher
up to avoid deadlocks caused by using the leaf in the path.

Signed-off-by: Chris Mason <clm@fb.com>
cc: stable@vger.kernel.org # v3.7+
cc: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:28 -07:00
David Sterba
849ef9286f btrfs: check unsupported filters in balance arguments
We don't verify that all the balance filter arguments supplemented by
the flags are actually known to the kernel. Thus we let it silently pass
and do nothing.

At the moment this means only the 'limit' filter, but we're going to add
a few more soon so it's better to have that fixed. Also in older stable
kernels so that it works with newer userspace tools.

Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-10-26 19:38:26 -07:00