The hole punching can result in adding new leafs (and as a consequence
new nodes) to the tree because when we find file extent items that span
beyond the hole range we may end up not deleting them (just adjusting
them, reducing their range by reducing their length or increasing their
offset field) and add new file extent items representing holes.

So after splitting a leaf (therefore creating a new one) to insert a new
file extent item representing a hole, a new node might be added to each
level of the tree in the worst case scenario (since there's a new key
and every parent node was full).

For example if a file has an extent item representing the range 0 to 64Mb
and we punch a hole in the range 1Mb to 20Mb, the existing extent item is
duplicated and one of the copies is adjusted to represent the range 0 to
1Mb, the other copy adjusted to represent the range 20Mb to 64Mb, and a
new file extent item representing a hole in the range 1Mb to 20Mb is
inserted.

Fix this by using btrfs_calc_trans_metadata_size() instead of
btrfs_calc_trunc_metadata_size(), so that enough metadata space is
reserved for the worst possible case.
Signed-off-by: NRobbie Ko <robbieko@synology.com>
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
[Modified changelog for clarity and correctness]

We were setting the qgroup_rescan_running flag to true only after the
rescan worker started (which is a task run by a queue). So if a user
space task starts a rescan and immediately after asks to wait for the
rescan worker to finish, this second call might happen before the rescan
worker task starts running, in which case the rescan wait ioctl returns
immediatley, not waiting for the rescan worker to finish.

This was making the fstest btrfs/022 fail very often.

Fixes: d2c609b8 (btrfs: properly track when rescan worker is running)
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>

We can not simply use the owner field from an extent buffer's header to
get the id of the respective tree when the extent buffer is from a
relocation tree. When we create the root for a relocation tree we leave
(on purpose) the owner field with the same value as the subvolume's tree
root (we do this at ctree.c:btrfs_copy_root()). So we must ignore extent
buffers from relocation trees, which have the BTRFS_HEADER_FLAG_RELOC
flag set, because otherwise we will always consider the extent buffer
as not being the root of the tree (the root of original subvolume tree
is always different from the root of the respective relocation tree).

This lead to assertion failures when running with the integrity checker
enabled (CONFIG_BTRFS_FS_CHECK_INTEGRITY=y) such as the following:

[  643.393409] BTRFS critical (device sdg): corrupt leaf, non-root leaf's nritems is 0: block=38506496, root=260, slot=0
[  643.397609] BTRFS info (device sdg): leaf 38506496 total ptrs 0 free space 3995
[  643.407075] assertion failed: 0, file: fs/btrfs/disk-io.c, line: 4078
[  643.408425] ------------[ cut here ]------------
[  643.409112] kernel BUG at fs/btrfs/ctree.h:3419!
[  643.409773] invalid opcode: 0000 [#1] PREEMPT SMP
[  643.410447] Modules linked in: dm_flakey dm_mod crc32c_generic btrfs xor raid6_pq ppdev psmouse acpi_cpufreq parport_pc evdev parport tpm_tis tpm_tis_core pcspkr serio_raw i2c_piix4 sg tpm i2c_core button processor loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring scsi_mod virtio e1000 floppy
[  643.414356] CPU: 11 PID: 32726 Comm: btrfs Not tainted 4.8.0-rc8-btrfs-next-35+ #1
[  643.414356] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[  643.414356] task: ffff880145e95b00 task.stack: ffff88014826c000
[  643.414356] RIP: 0010:[<ffffffffa0352759>]  [<ffffffffa0352759>] assfail.constprop.41+0x1c/0x1e [btrfs]
[  643.414356] RSP: 0018:ffff88014826fa28  EFLAGS: 00010292
[  643.414356] RAX: 0000000000000039 RBX: ffff88014e2d7c38 RCX: 0000000000000001
[  643.414356] RDX: ffff88023f4d2f58 RSI: ffffffff81806c63 RDI: 00000000ffffffff
[  643.414356] RBP: ffff88014826fa28 R08: 0000000000000001 R09: 0000000000000000
[  643.414356] R10: ffff88014826f918 R11: ffffffff82f3c5ed R12: ffff880172910000
[  643.414356] R13: ffff880233992230 R14: ffff8801a68a3310 R15: fffffffffffffff8
[  643.414356] FS:  00007f9ca305e8c0(0000) GS:ffff88023f4c0000(0000) knlGS:0000000000000000
[  643.414356] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  643.414356] CR2: 00007f9ca3071000 CR3: 000000015d01b000 CR4: 00000000000006e0
[  643.414356] Stack:
[  643.414356]  ffff88014826fa50 ffffffffa02d655a 000000000000000a ffff88014e2d7c38
[  643.414356]  0000000000000000 ffff88014826faa8 ffffffffa02b72f3 ffff88014826fab8
[  643.414356]  00ffffffa03228e4 0000000000000000 0000000000000000 ffff8801bbd4e000
[  643.414356] Call Trace:
[  643.414356]  [<ffffffffa02d655a>] btrfs_mark_buffer_dirty+0xdf/0xe5 [btrfs]
[  643.414356]  [<ffffffffa02b72f3>] btrfs_copy_root+0x18a/0x1d1 [btrfs]
[  643.414356]  [<ffffffffa0322921>] create_reloc_root+0x72/0x1ba [btrfs]
[  643.414356]  [<ffffffffa03267c2>] btrfs_init_reloc_root+0x7b/0xa7 [btrfs]
[  643.414356]  [<ffffffffa02d9e44>] record_root_in_trans+0xdf/0xed [btrfs]
[  643.414356]  [<ffffffffa02db04e>] btrfs_record_root_in_trans+0x50/0x6a [btrfs]
[  643.414356]  [<ffffffffa030ad2b>] create_subvol+0x472/0x773 [btrfs]
[  643.414356]  [<ffffffffa030b406>] btrfs_mksubvol+0x3da/0x463 [btrfs]
[  643.414356]  [<ffffffffa030b406>] ? btrfs_mksubvol+0x3da/0x463 [btrfs]
[  643.414356]  [<ffffffff810781ac>] ? preempt_count_add+0x65/0x68
[  643.414356]  [<ffffffff811a6e97>] ? __mnt_want_write+0x62/0x77
[  643.414356]  [<ffffffffa030b55d>] btrfs_ioctl_snap_create_transid+0xce/0x187 [btrfs]
[  643.414356]  [<ffffffffa030b67d>] btrfs_ioctl_snap_create+0x67/0x81 [btrfs]
[  643.414356]  [<ffffffffa030ecfd>] btrfs_ioctl+0x508/0x20dd [btrfs]
[  643.414356]  [<ffffffff81293e39>] ? __this_cpu_preempt_check+0x13/0x15
[  643.414356]  [<ffffffff81155eca>] ? handle_mm_fault+0x976/0x9ab
[  643.414356]  [<ffffffff81091300>] ? arch_local_irq_save+0x9/0xc
[  643.414356]  [<ffffffff8119a2b0>] vfs_ioctl+0x18/0x34
[  643.414356]  [<ffffffff8119a8e8>] do_vfs_ioctl+0x581/0x600
[  643.414356]  [<ffffffff814b9552>] ? entry_SYSCALL_64_fastpath+0x5/0xa8
[  643.414356]  [<ffffffff81093fe9>] ? trace_hardirqs_on_caller+0x17b/0x197
[  643.414356]  [<ffffffff8119a9be>] SyS_ioctl+0x57/0x79
[  643.414356]  [<ffffffff814b9565>] entry_SYSCALL_64_fastpath+0x18/0xa8
[  643.414356]  [<ffffffff81091b08>] ? trace_hardirqs_off_caller+0x3f/0xaa
[  643.414356] Code: 89 83 88 00 00 00 31 c0 5b 41 5c 41 5d 5d c3 55 89 f1 48 c7 c2 98 bc 35 a0 48 89 fe 48 c7 c7 05 be 35 a0 48 89 e5 e8 13 46 dd e0 <0f> 0b 55 89 f1 48 c7 c2 9f d3 35 a0 48 89 fe 48 c7 c7 7a d5 35
[  643.414356] RIP  [<ffffffffa0352759>] assfail.constprop.41+0x1c/0x1e [btrfs]
[  643.414356]  RSP <ffff88014826fa28>
[  643.468267] ---[ end trace 6a1b3fb1a9d7d6e3 ]---

This can be easily reproduced by running xfstests with the integrity
checker enabled.

Fixes: 1ba98d08 (Btrfs: detect corruption when non-root leaf has zero item)
Cc: stable@vger.kernel.org  # 4.8+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>

This can only happen with CONFIG_BTRFS_FS_CHECK_INTEGRITY=y.

Commit 1ba98d08 ("Btrfs: detect corruption when non-root leaf has zero item")
assumes that a leaf is its root when leaf->bytenr == btrfs_root_bytenr(root),
however, we should not use btrfs_root_bytenr(root) since it's mainly got
updated during committing transaction.  So the check can fail when doing
COW on this leaf while it is a root.

This changes to use "if (leaf == btrfs_root_node(root))" instead, just like
how we check whether leaf is a root in __btrfs_cow_block().

Fixes: 1ba98d08 (Btrfs: detect corruption when non-root leaf has zero item)
Cc: stable@vger.kernel.org  # 4.8+
Reported-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NFilipe Manana <fdmanana@suse.com>

After the last big change in the delayed references code that was needed
for the last qgroups rework, the red black tree node field of struct
btrfs_delayed_ref_node is no longer used, so just remove it, this helps
us save some memory (since struct rb_node is 24 bytes on x86_64) for
these structures.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>

In commit 5bc7247a (Btrfs: fix broken nocow after balance) we started
abusing the rtransid and otransid fields of root items from relocation
trees to fix some issues with nodatacow mode. However later in commit
ba8b0289 (Btrfs: do not reset last_snapshot after relocation) we
dropped the code that made use of those fields but did not remove
the code that sets those fields.

So just remove them to avoid confusion.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>

During relocation of a data block group we create a relocation tree
for each fs/subvol tree by making a snapshot of each tree using
btrfs_copy_root() and the tree's commit root, and then setting the last
snapshot field for the fs/subvol tree's root to the value of the current
transaction id minus 1. However this can lead to relocation later
dropping references that it did not create if we have qgroups enabled,
leaving the filesystem in an inconsistent state that keeps aborting
transactions.

Lets consider the following example to explain the problem, which requires
qgroups to be enabled.

We are relocating data block group Y, we have a subvolume with id 258 that
has a root at level 1, that subvolume is used to store directory entries
for snapshots and we are currently at transaction 3404.

When committing transaction 3404, we have a pending snapshot and therefore
we call btrfs_run_delayed_items() at transaction.c:create_pending_snapshot()
in order to create its dentry at subvolume 258. This results in COWing
leaf A from root 258 in order to add the dentry. Note that leaf A
also contains file extent items referring to extents from some other
block group X (we are currently relocating block group Y). Later on, still
at create_pending_snapshot() we call qgroup_account_snapshot(), which
switches the commit root for root 258 when it calls switch_commit_roots(),
so now the COWed version of leaf A, lets call it leaf A', is accessible
from the commit root of tree 258. At the end of qgroup_account_snapshot(),
we call record_root_in_trans() with 258 as its argument, which results
in btrfs_init_reloc_root() being called, which in turn calls
relocation.c:create_reloc_root() in order to create a relocation tree
associated to root 258, which results in assigning the value of 3403
(which is the current transaction id minus 1 = 3404 - 1) to the
last_snapshot field of root 258. When creating the relocation tree root
at ctree.c:btrfs_copy_root() we add a shared reference for leaf A',
corresponding to the relocation tree's root, when we call btrfs_inc_ref()
against the COWed root (a copy of the commit root from tree 258), which
is at level 1. So at this point leaf A' has 2 references, one normal
reference corresponding to root 258 and one shared reference corresponding
to the root of the relocation tree.

Transaction 3404 finishes its commit and transaction 3405 is started by
relocation when calling merge_reloc_root() for the relocation tree
associated to root 258. In the meanwhile leaf A' is COWed again, in
response to some filesystem operation, when we are still at transaction
3405. However when we COW leaf A', at ctree.c:update_ref_for_cow(), we
call btrfs_block_can_be_shared() in order to figure out if other trees
refer to the leaf and if any such trees exists, add a full back reference
to leaf A' - but btrfs_block_can_be_shared() incorrectly returns false
because the following condition is false:

  btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item)

which evaluates to 3404 <= 3403. So after leaf A' is COWed, it stays with
only one reference, corresponding to the shared reference we created when
we called btrfs_copy_root() to create the relocation tree's root and
btrfs_inc_ref() ends up not being called for leaf A' nor we end up setting
the flag BTRFS_BLOCK_FLAG_FULL_BACKREF in leaf A'. This results in not
adding shared references for the extents from block group X that leaf A'
refers to with its file extent items.

Later, after merging the relocation root we do a call to to
btrfs_drop_snapshot() in order to delete the relocation tree. This ends
up calling do_walk_down() when path->slots[1] points to leaf A', which
results in calling btrfs_lookup_extent_info() to get the number of
references for leaf A', which is 1 at this time (only the shared reference
exists) and this value is stored at wc->refs[0]. After this walk_up_proc()
is called when wc->level is 0 and path->nodes[0] corresponds to leaf A'.
Because the current level is 0 and wc->refs[0] is 1, it does call
btrfs_dec_ref() against leaf A', which results in removing the single
references that the extents from block group X have which are associated
to root 258 - the expectation was to have each of these extents with 2
references - one reference for root 258 and one shared reference related
to the root of the relocation tree, and so we would drop only the shared
reference (because leaf A' was supposed to have the flag
BTRFS_BLOCK_FLAG_FULL_BACKREF set).

This leaves the filesystem in an inconsistent state as we now have file
extent items in a subvolume tree that point to extents from block group X
without references in the extent tree. So later on when we try to decrement
the references for these extents, for example due to a file unlink operation,
truncate operation or overwriting ranges of a file, we fail because the
expected references do not exist in the extent tree.

This leads to warnings and transaction aborts like the following:

[  588.965795] ------------[ cut here ]------------
[  588.965815] WARNING: CPU: 2 PID: 2479 at fs/btrfs/extent-tree.c:1625 lookup_inline_extent_backref+0x432/0x5b0 [btrfs]
[  588.965816] Modules linked in: af_packet iscsi_ibft iscsi_boot_sysfs xfs libcrc32c ppdev acpi_cpufreq button tpm_tis e1000 i2c_piix4 pcspkr parport_pc
parport tpm qemu_fw_cfg joydev btrfs xor raid6_pq sr_mod cdrom ata_generic virtio_scsi ata_piix virtio_pci bochs_drm virtio_ring drm_kms_helper syscopyarea
sysfillrect sysimgblt fb_sys_fops virtio ttm serio_raw drm floppy sg
[  588.965831] CPU: 2 PID: 2479 Comm: kworker/u8:7 Not tainted 4.7.3-3-default-fdm+ #1
[  588.965832] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[  588.965844] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
[  588.965845]  0000000000000000 ffff8802263bfa28 ffffffff813af542 0000000000000000
[  588.965847]  0000000000000000 ffff8802263bfa68 ffffffff81081e8b 0000065900000000
[  588.965848]  ffff8801db2af000 000000012bbe2000 0000000000000000 ffff880215703b48
[  588.965849] Call Trace:
[  588.965852]  [<ffffffff813af542>] dump_stack+0x63/0x81
[  588.965854]  [<ffffffff81081e8b>] __warn+0xcb/0xf0
[  588.965855]  [<ffffffff81081f7d>] warn_slowpath_null+0x1d/0x20
[  588.965863]  [<ffffffffa0175042>] lookup_inline_extent_backref+0x432/0x5b0 [btrfs]
[  588.965865]  [<ffffffff81143220>] ? trace_clock_local+0x10/0x30
[  588.965867]  [<ffffffff8114c5df>] ? rb_reserve_next_event+0x6f/0x460
[  588.965875]  [<ffffffffa0175215>] insert_inline_extent_backref+0x55/0xd0 [btrfs]
[  588.965882]  [<ffffffffa017531f>] __btrfs_inc_extent_ref.isra.55+0x8f/0x240 [btrfs]
[  588.965890]  [<ffffffffa017acea>] __btrfs_run_delayed_refs+0x74a/0x1260 [btrfs]
[  588.965892]  [<ffffffff810cb046>] ? cpuacct_charge+0x86/0xa0
[  588.965900]  [<ffffffffa017e74f>] btrfs_run_delayed_refs+0x9f/0x2c0 [btrfs]
[  588.965908]  [<ffffffffa017ea04>] delayed_ref_async_start+0x94/0xb0 [btrfs]
[  588.965918]  [<ffffffffa01c799a>] btrfs_scrubparity_helper+0xca/0x350 [btrfs]
[  588.965928]  [<ffffffffa01c7c5e>] btrfs_extent_refs_helper+0xe/0x10 [btrfs]
[  588.965930]  [<ffffffff8109b323>] process_one_work+0x1f3/0x4e0
[  588.965931]  [<ffffffff8109b658>] worker_thread+0x48/0x4e0
[  588.965932]  [<ffffffff8109b610>] ? process_one_work+0x4e0/0x4e0
[  588.965934]  [<ffffffff810a1659>] kthread+0xc9/0xe0
[  588.965936]  [<ffffffff816f2f1f>] ret_from_fork+0x1f/0x40
[  588.965937]  [<ffffffff810a1590>] ? kthread_worker_fn+0x170/0x170
[  588.965938] ---[ end trace 34e5232c933a1749 ]---
[  588.966187] ------------[ cut here ]------------
[  588.966196] WARNING: CPU: 2 PID: 2479 at fs/btrfs/extent-tree.c:2966 btrfs_run_delayed_refs+0x28c/0x2c0 [btrfs]
[  588.966196] BTRFS: Transaction aborted (error -5)
[  588.966197] Modules linked in: af_packet iscsi_ibft iscsi_boot_sysfs xfs libcrc32c ppdev acpi_cpufreq button tpm_tis e1000 i2c_piix4 pcspkr parport_pc
parport tpm qemu_fw_cfg joydev btrfs xor raid6_pq sr_mod cdrom ata_generic virtio_scsi ata_piix virtio_pci bochs_drm virtio_ring drm_kms_helper syscopyarea
sysfillrect sysimgblt fb_sys_fops virtio ttm serio_raw drm floppy sg
[  588.966206] CPU: 2 PID: 2479 Comm: kworker/u8:7 Tainted: G        W       4.7.3-3-default-fdm+ #1
[  588.966207] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[  588.966217] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
[  588.966217]  0000000000000000 ffff8802263bfc98 ffffffff813af542 ffff8802263bfce8
[  588.966219]  0000000000000000 ffff8802263bfcd8 ffffffff81081e8b 00000b96345ee000
[  588.966220]  ffffffffa021ae1c ffff880215703b48 00000000000005fe ffff8802345ee000
[  588.966221] Call Trace:
[  588.966223]  [<ffffffff813af542>] dump_stack+0x63/0x81
[  588.966224]  [<ffffffff81081e8b>] __warn+0xcb/0xf0
[  588.966225]  [<ffffffff81081eff>] warn_slowpath_fmt+0x4f/0x60
[  588.966233]  [<ffffffffa017e93c>] btrfs_run_delayed_refs+0x28c/0x2c0 [btrfs]
[  588.966241]  [<ffffffffa017ea04>] delayed_ref_async_start+0x94/0xb0 [btrfs]
[  588.966250]  [<ffffffffa01c799a>] btrfs_scrubparity_helper+0xca/0x350 [btrfs]
[  588.966259]  [<ffffffffa01c7c5e>] btrfs_extent_refs_helper+0xe/0x10 [btrfs]
[  588.966260]  [<ffffffff8109b323>] process_one_work+0x1f3/0x4e0
[  588.966261]  [<ffffffff8109b658>] worker_thread+0x48/0x4e0
[  588.966263]  [<ffffffff8109b610>] ? process_one_work+0x4e0/0x4e0
[  588.966264]  [<ffffffff810a1659>] kthread+0xc9/0xe0
[  588.966265]  [<ffffffff816f2f1f>] ret_from_fork+0x1f/0x40
[  588.966267]  [<ffffffff810a1590>] ? kthread_worker_fn+0x170/0x170
[  588.966268] ---[ end trace 34e5232c933a174a ]---
[  588.966269] BTRFS: error (device sda2) in btrfs_run_delayed_refs:2966: errno=-5 IO failure
[  588.966270] BTRFS info (device sda2): forced readonly

This was happening often on openSUSE and SLE systems using btrfs as the
root filesystem (with its default layout where multiple subvolumes are
used) where balance happens in the background triggered by a cron job and
snapshots are automatically created before/after package installations,
upgrades and removals. The issue could be triggered simply by running the
following loop on the first system boot post installation:

  while true; do
     zypper -n in nfs-kernel-server
     zypper -n rm nfs-kernel-server
  done

(If we were fast enough and made that loop before the cron job triggered
a balance operation and the balance finished)

So fix by setting the last_snapshot field of the root to the value of the
generation of its commit root. Like this btrfs_block_can_be_shared()
behaves correctly for the case where the relocation root is created during
a transaction commit and for the case where it's created before a
transaction commit.

Fixes: 6426c7ad (btrfs: qgroup: Fix qgroup accounting when creating snapshot)
Cc: stable@vger.kernel.org  # 4.7+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>

Merge branch 'for-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.9

btrfs_remove_all_log_ctxs takes a shortcut where it avoids walking the
list because it knows all of the waiters are patiently waiting for the
commit to finish.

But, there's a small race where btrfs_sync_log can remove itself from
the list if it finds a log commit is already done.  Also, it uses
list_del_init() to remove itself from the list, but there's no way to
know if btrfs_remove_all_log_ctxs has already run, so we don't know for
sure if it is safe to call list_del_init().

This gets rid of all the shortcuts for btrfs_remove_all_log_ctxs(), and
just calls it with the proper locking.

This is part two of the corruption fixed by cbd60aa7.  I should have
done this in the first place, but convinced myself the optimizations were
safe.  A 12 hour run of dbench 2048 will eventually trigger a list debug
WARN_ON for the list_del_init() in btrfs_sync_log().

Fixes: d1433debReported-by: NDave Jones <davej@codemonkey.org.uk>
cc: stable@vger.kernel.org # 3.15+
Signed-off-by: NChris Mason <clm@fb.com>

This issue was found when testing in-band dedupe enospc behaviour,
sometimes run_one_delayed_ref() may fail for enospc reason, then
__btrfs_run_delayed_refs（）will return, but forget to add num_heads_read
back, which will trigger "WARN_ON(delayed_refs->num_heads_ready == 0)" in
btrfs_select_ref_head().
Signed-off-by: NWang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We cast 0 to a u8 but then because of type promotion, it's immediately
cast to int back to int before we do a bitwise negate.  The cast doesn't
matter in this case, the code works as intended.  It causes a static
checker warning though so let's remove it.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In btrfs_truncate_inode_items()->btrfs_async_run_delayed_refs(), we
swap the arg2 and arg3 wrongly, fix this.

This bug just impacts asynchronous delayed refs handle when we truncate inodes.
In delayed_ref_async_start(), there is such codes:

    trans = btrfs_join_transaction(async->root);
    if (trans->transid > async->transid)
        goto end;
    ret = btrfs_run_delayed_refs(trans, async->root, async->count);

From this codes, we can see that this just influence whether can we handle
delayed refs or the number of delayed refs to handle, this may impact
performance, but will not result in missing delayed refs, all delayed refs will
be handled in btrfs_commit_transaction().
Signed-off-by: NWang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Indeed this just make the behavior similar to xfs when process has
fatal signals pending, and it'll make fstests/generic/298 happy.
Signed-off-by: NWang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

While free'ing qgroup->reserved resources, we much check if
the page has not been invalidated by a truncate operation
by checking if the page is still dirty before reducing the
qgroup resources. Resources in such a case are free'd when
the entire extent is released by delayed_ref.

This fixes a double accounting while releasing resources
in case of truncating a file, reproduced by the following testcase.

SCRATCH_DEV=/dev/vdb
SCRATCH_MNT=/mnt
mkfs.btrfs -f $SCRATCH_DEV
mount -t btrfs $SCRATCH_DEV $SCRATCH_MNT
cd $SCRATCH_MNT
btrfs quota enable $SCRATCH_MNT
btrfs subvolume create a
btrfs qgroup limit 500m a $SCRATCH_MNT
sync
for c in {1..15}; do
dd if=/dev/zero  bs=1M count=40 of=$SCRATCH_MNT/a/file;
done

sleep 10
sync
sleep 5

touch $SCRATCH_MNT/a/newfile

echo "Removing file"
rm $SCRATCH_MNT/a/file

Fixes: b9d0b389 ("btrfs: Add handler for invalidate page")
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Merge branch 'for-chris-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.9

While updating btree, we try to push items between sibling
nodes/leaves in order to keep height as low as possible.
But we don't memset the original places with zero when
pushing items so that we could end up leaving stale content
in nodes/leaves.  One may read the above stale content by
increasing btree blocks' @nritems.

One case I've come across is that in fs tree, a leaf has two
parent nodes, hence running balance ends up with processing
this leaf with two parent nodes, but it can only reach the
valid parent node through btrfs_search_slot, so it'd be like,

do_relocation
    for P in all parent nodes of block A:
        if !P->eb:
            btrfs_search_slot(key);   --> get path from P to A.
        if lowest:
            BUG_ON(A->bytenr != bytenr of A recorded in P);
        btrfs_cow_block(P, A);   --> change A's bytenr in P.

After btrfs_cow_block, P has the new bytenr of A, but with the
same @key, we get the same path again, and get panic by BUG_ON.

Note that this is only happening in a corrupted fs, for a
regular fs in which we have correct @nritems so that we won't
read stale content in any case.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Merge branch 'fst-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.9
Signed-off-by: NChris Mason <clm@fb.com>

Commit 95155585 ("Btrfs: send, don't bug on inconsistent snapshots")
removed some BUG_ON() statements (replacing them with returning errors
to user space and logging error messages) when a snapshot is in an
inconsistent state due to failures to update a delayed inode item (ENOMEM
or ENOSPC) after adding/updating/deleting references, xattrs or file
extent items.

However there is a case, when no errors happen, where a file extent item
can be modified without having the corresponding inode item updated. This
case happens during balance under very specific timings, when relocation
is in the stage where it updates data pointers and a leaf that contains
file extent items is COWed. When that happens file extent items get their
disk_bytenr field updated to a new value that reflects the post relocation
logical address of the extent, without updating their respective inode
items (as there is nothing that needs to be updated on them). This is
performed at relocation.c:replace_file_extents() through
relocation.c:btrfs_reloc_cow_block().

So make an incremental send deal with this case and don't do any processing
for a file extent item that got its disk_bytenr field updated by relocation,
since the extent's data is the same as the one pointed by the file extent
item in the parent snapshot.

After the recent commit mentioned above this case resulted in EIO errors
returned to user space (and an error message logged to dmesg/syslog) when
doing an incremental send, while before it, it resulted in hitting a
BUG_ON leading to the following trace:

[  952.206705] ------------[ cut here ]------------
[  952.206714] kernel BUG at ../fs/btrfs/send.c:5653!
[  952.206719] Internal error: Oops - BUG: 0 [#1] SMP
[  952.209854] Modules linked in: st dm_mod nls_utf8 isofs fuse nf_log_ipv6 xt_pkttype xt_physdev br_netfilter nf_log_ipv4 nf_log_common xt_LOG xt_limit ebtable_filter ebtables af_packet bridge stp llc ip6t_REJECT xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_raw ipt_REJECT iptable_raw xt_CT iptable_filter ip6table_mangle nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ipv4 nf_defrag_ipv4 ip_tables xt_conntrack nf_conntrack ip6table_filter ip6_tables x_tables xfs libcrc32c nls_iso8859_1 nls_cp437 vfat fat joydev aes_ce_blk ablk_helper cryptd snd_intel8x0 aes_ce_cipher snd_ac97_codec ac97_bus snd_pcm ghash_ce sha2_ce sha1_ce snd_timer snd virtio_net soundcore btrfs xor sr_mod cdrom hid_generic usbhid raid6_pq virtio_blk virtio_scsi bochs_drm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm virtio_mmio xhci_pci xhci_hcd usbcore usb_common virtio_pci virtio_ring virtio drm sg efivarfs
[  952.228333] Supported: Yes
[  952.228908] CPU: 0 PID: 12779 Comm: snapperd Not tainted 4.4.14-50-default #1
[  952.230329] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[  952.231683] task: ffff800058e94100 ti: ffff8000d866c000 task.ti: ffff8000d866c000
[  952.233279] PC is at changed_cb+0x9f4/0xa48 [btrfs]
[  952.234375] LR is at changed_cb+0x58/0xa48 [btrfs]
[  952.236552] pc : [<ffff7ffffc39de7c>] lr : [<ffff7ffffc39d4e0>] pstate: 80000145
[  952.238049] sp : ffff8000d866fa20
[  952.238732] x29: ffff8000d866fa20 x28: 0000000000000019
[  952.239840] x27: 00000000000028d5 x26: 00000000000024a2
[  952.241008] x25: 0000000000000002 x24: ffff8000e66e92f0
[  952.242131] x23: ffff8000b8c76800 x22: ffff800092879140
[  952.243238] x21: 0000000000000002 x20: ffff8000d866fb78
[  952.244348] x19: ffff8000b8f8c200 x18: 0000000000002710
[  952.245607] x17: 0000ffff90d42480 x16: ffff800000237dc0
[  952.246719] x15: 0000ffff90de7510 x14: ab000c000a2faf08
[  952.247835] x13: 0000000000577c2b x12: ab000c000b696665
[  952.248981] x11: 2e65726f632f6966 x10: 652d34366d72612f
[  952.250101] x9 : 32627572672f746f x8 : ab000c00092f1671
[  952.251352] x7 : 8000000000577c2b x6 : ffff800053eadf45
[  952.252468] x5 : 0000000000000000 x4 : ffff80005e169494
[  952.253582] x3 : 0000000000000004 x2 : ffff8000d866fb78
[  952.254695] x1 : 000000000003e2a3 x0 : 000000000003e2a4
[  952.255803]
[  952.256150] Process snapperd (pid: 12779, stack limit = 0xffff8000d866c020)
[  952.257516] Stack: (0xffff8000d866fa20 to 0xffff8000d8670000)
[  952.258654] fa20: ffff8000d866fae0 ffff7ffffc308fc0 ffff800092879140 ffff8000e66e92f0
[  952.260219] fa40: 0000000000000035 ffff800055de6000 ffff8000b8c76800 ffff8000d866fb78
[  952.261745] fa60: 0000000000000002 00000000000024a2 00000000000028d5 0000000000000019
[  952.263269] fa80: ffff8000d866fae0 ffff7ffffc3090f0 ffff8000d866fae0 ffff7ffffc309128
[  952.264797] faa0: ffff800092879140 ffff8000e66e92f0 0000000000000035 ffff800055de6000
[  952.268261] fac0: ffff8000b8c76800 ffff8000d866fb78 0000000000000002 0000000000001000
[  952.269822] fae0: ffff8000d866fbc0 ffff7ffffc39ecfc ffff8000b8f8c200 ffff8000b8f8c368
[  952.271368] fb00: ffff8000b8f8c378 ffff800055de6000 0000000000000001 ffff8000ecb17500
[  952.272893] fb20: ffff8000b8c76800 ffff800092879140 ffff800062b6d000 ffff80007a9e2470
[  952.274420] fb40: ffff8000b8f8c208 0000000005784000 ffff8000580a8000 ffff8000b8f8c200
[  952.276088] fb60: ffff7ffffc39d488 00000002b8f8c368 0000000000000000 000000000003e2a4
[  952.280275] fb80: 000000000000006c ffff7ffffc39ec00 000000000003e2a4 000000000000006c
[  952.283219] fba0: ffff8000b8f8c300 0000000000000100 0000000000000001 ffff8000ecb17500
[  952.286166] fbc0: ffff8000d866fcd0 ffff7ffffc3643c0 ffff8000f8842700 0000ffff8ffe9278
[  952.289136] fbe0: 0000000040489426 ffff800055de6000 0000ffff8ffe9278 0000000040489426
[  952.292083] fc00: 000000000000011d 000000000000001d ffff80007a9e4598 ffff80007a9e43e8
[  952.294959] fc20: ffff8000b8c7693f 0000000000003b24 0000000000000019 ffff8000b8f8c218
[  952.301161] fc40: 00000001d866fc70 ffff8000b8c76800 0000000000000128 ffffffffffffff84
[  952.305749] fc60: ffff800058e941ff 0000000000003a58 ffff8000d866fcb0 ffff8000000f7390
[  952.308875] fc80: 000000000000012a 0000000000010290 ffff8000d866fc00 000000000000007b
[  952.311915] fca0: 0000000000010290 ffff800046c1b100 74732d7366727462 000001006d616572
[  952.314937] fcc0: ffff8000fffc4100 cb88537fdc8ba60e ffff8000d866fe10 ffff8000002499e8
[  952.318008] fce0: 0000000040489426 ffff8000f8842700 0000ffff8ffe9278 ffff80007a9e4598
[  952.321321] fd00: 0000ffff8ffe9278 0000000040489426 000000000000011d 000000000000001d
[  952.324280] fd20: ffff80000072c000 ffff8000d866c000 ffff8000d866fda0 ffff8000000e997c
[  952.327156] fd40: ffff8000fffc4180 00000000000031ed ffff8000fffc4180 ffff800046c1b7d4
[  952.329895] fd60: 0000000000000140 0000ffff907ea170 000000000000011d 00000000000000dc
[  952.334641] fd80: ffff80000072c000 ffff8000d866c000 0000000000000000 0000000000000002
[  952.338002] fda0: ffff8000d866fdd0 ffff8000000ebacc ffff800046c1b080 ffff800046c1b7d4
[  952.340724] fdc0: ffff8000d866fdf0 ffff8000000db67c 0000000000000040 ffff800000e69198
[  952.343415] fde0: 0000ffff8ffea790 00000000000031ed ffff8000d866fe20 ffff800000254000
[  952.346101] fe00: 000000000000001d 0000000000000004 ffff8000d866fe90 ffff800000249d3c
[  952.348980] fe20: ffff8000f8842700 0000000000000000 ffff8000f8842701 0000000000000008
[  952.351696] fe40: ffff8000d866fe70 0000000000000008 ffff8000d866fe90 ffff800000249cf8
[  952.354387] fe60: ffff8000f8842700 0000ffff8ffe9170 ffff8000f8842701 0000000000000008
[  952.357083] fe80: 0000ffff8ffe9278 ffff80008ff85500 0000ffff8ffe90c0 ffff800000085c84
[  952.359800] fea0: 0000000000000000 0000ffff8ffe9170 ffffffffffffffff 0000ffff90d473bc
[  952.365351] fec0: 0000000000000000 0000000000000015 0000000000000008 0000000040489426
[  952.369550] fee0: 0000ffff8ffe9278 0000ffff907ea790 0000ffff907ea170 0000ffff907ea790
[  952.372416] ff00: 0000ffff907ea170 0000000000000000 000000000000001d 0000000000000004
[  952.375223] ff20: 0000ffff90a32220 00000000003d0f00 0000ffff907ea0a0 0000ffff8ffe8f30
[  952.378099] ff40: 0000ffff9100f554 0000ffff91147000 0000ffff91117bc0 0000ffff90d473b0
[  952.381115] ff60: 0000ffff9100f620 0000ffff880069b0 0000ffff8ffe9170 0000ffff8ffe91a0
[  952.384003] ff80: 0000ffff8ffe9160 0000ffff8ffe9140 0000ffff88006990 0000ffff8ffe9278
[  952.386860] ffa0: 0000ffff88008a60 0000ffff8ffe9480 0000ffff88014ca0 0000ffff8ffe90c0
[  952.389654] ffc0: 0000ffff910be8e8 0000ffff8ffe90c0 0000ffff90d473bc 0000000000000000
[  952.410986] ffe0: 0000000000000008 000000000000001d 6e2079747265706f 72616d223d656d61
[  952.415497] Call trace:
[  952.417403] [<ffff7ffffc39de7c>] changed_cb+0x9f4/0xa48 [btrfs]
[  952.420023] [<ffff7ffffc308fc0>] btrfs_compare_trees+0x500/0x6b0 [btrfs]
[  952.422759] [<ffff7ffffc39ecfc>] btrfs_ioctl_send+0xb4c/0xe10 [btrfs]
[  952.425601] [<ffff7ffffc3643c0>] btrfs_ioctl+0x374/0x29a4 [btrfs]
[  952.428031] [<ffff8000002499e8>] do_vfs_ioctl+0x33c/0x600
[  952.430360] [<ffff800000249d3c>] SyS_ioctl+0x90/0xa4
[  952.432552] [<ffff800000085c84>] el0_svc_naked+0x38/0x3c
[  952.434803] Code: 2a1503e0 17fffdac b9404282 17ffff28 (d4210000)
[  952.437457] ---[ end trace 9afd7090c466cf15 ]---
Signed-off-by: NFilipe Manana <fdmanana@suse.com>

This reverts commit 5d8eb6fe.

When we remove devices, we free the device structures.  Delaying
btfs_remove_chunk() ends up hitting a use-after-free on them.
Signed-off-by: NChris Mason <clm@fb.com>

The recommended way is to put all members on separate lines.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We don't change the given extent ranges, mark them const to catch
accidental changes.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The free space tree format conversion functions were broken on
big-endian systems, but the sanity tests didn't catch it because all of
the operations were aligned to multiple words. This was meant to catch
any bugs in the extent buffer code's handling of high memory, but it
ended up hiding the endianness bug. Expand the tests to do both
sector-aligned and page-aligned operations.
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The in-memory bitmap code manipulates words and is therefore sensitive
to endianness, while the extent buffer bitmap code addresses bytes and
is byte-order agnostic. Because the byte addressing of the extent buffer
bitmaps is equivalent to a little-endian in-memory bitmap, the extent
buffer bitmap tests fail on big-endian systems.

34b3e6c9 ("Btrfs: self-tests: Fix extent buffer bitmap test fail on
BE system") worked around another endianness bug in the tests but missed
this one because ed9e4afd ("Btrfs: self-tests: Execute page
straddling test only when nodesize < PAGE_SIZE") disables this part of
the test on ppc64. That change lost the original meaning of the test,
however. We really want to test that an equivalent series of operations
using the in-memory bitmap API and the extent buffer bitmap API produces
equivalent results.

To fix this, don't use memcmp_extent_buffer() or write_extent_buffer();
do everything bit-by-bit.
Reported-by: NAnatoly Pugachev <matorola@gmail.com>
Tested-by: NAnatoly Pugachev <matorola@gmail.com>
Tested-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are two separate issues that can lead to corrupted free space
trees.

1. The free space tree bitmaps had an endianness issue on big-endian
   systems which is fixed by an earlier patch in this series.
2. btrfs-progs before v4.7.3 modified filesystems without updating the
   free space tree.

To catch both of these issues at once, we need to force the free space
tree to be rebuilt. To do so, add a FREE_SPACE_TREE_VALID compat_ro bit.
If the bit isn't set, we know that it was either produced by a broken
big-endian kernel or may have been corrupted by btrfs-progs.

This also provides us with a way to add rudimentary read-write support
for the free space tree to btrfs-progs: it can just clear this bit and
have the kernel rebuild the free space tree.

Cc: stable@vger.kernel.org # 4.5+
Tested-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We moved the code for creating the free space tree the first time that
it's enabled, but didn't move the clearing code along with it. This
breaks my (undocumented) intention that `mount -o
clear_cache,space_cache=v2` would clear the free space tree and then
recreate it.

Fixes: 511711af ("btrfs: don't run delayed references while we are creating the free space tree")
Cc: stable@vger.kernel.org # 4.5+
Tested-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In convert_free_space_to_{bitmaps,extents}(), we buffer the free space
bitmaps in memory and copy them directly to/from the extent buffers with
{read,write}_extent_buffer(). The extent buffer bitmap helpers use byte
granularity, which is equivalent to a little-endian bitmap. This means
that on big-endian systems, the in-memory bitmaps will be written to
disk byte-swapped. To fix this, use byte-granularity for the bitmaps in
memory.

Fixes: a5ed9182 ("Btrfs: implement the free space B-tree")
Cc: stable@vger.kernel.org # 4.5+
Tested-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When we're not able to get enough space through splitting leaf,
we'd create a new sibling leaf instead, and it's possible that we return
 a zero-nritem sibling leaf and mark it dirty before it's in a consistent
state.  With CONFIG_BTRFS_FS_CHECK_INTEGRITY=y, the integrity check of
check_leaf will report panic due to this zero-nritem non-root leaf.

This removes the unnecessary btrfs_mark_buffer_dirty.
Reported-by: NFilipe Manana <fdmanana@gmail.com>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Really there's lots of things that can go wrong here, kill all the
BUG_ON()'s and replace the logic ones with ASSERT()'s and return EIO
instead.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
[ switched to btrfs_err, errors go to common label ]
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The addition of btrfs_no_printk() caused a build failure when
CONFIG_PRINTK is disabled:

fs/btrfs/send.c: In function 'send_rename':
fs/btrfs/ctree.h:3367:2: error: implicit declaration of function 'btrfs_no_printk' [-Werror=implicit-function-declaration]

This moves the helper outside of that #ifdef so it is always
defined, and changes the existing #ifdef to refer to that
helper as well for consistency.

Fixes: 47c57058ff2c ("btrfs: btrfs_debug should consume fs_info when DEBUG is not defined")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is an additional patch to
"Btrfs: memset to avoid stale content in btree node block".

This uses memset to initialize the unused space in a leaf to avoid
potential stale content, which may be incurred by pushing items
between sibling leaves.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Code cleanup. parent_start is initialized multiple times when it is
not necessary to do so.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Fixes: 7cf5b976 ("btrfs: qgroup: Cleanup old inaccurate facilities")
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Code cleanup. count is already (unsgined long)-1. That is the reason
run_all was set. Do not reassign it (unsigned long)-1.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

btrfs_show_devname() is using the device_list_mutex, sometimes
a call to blkdev_put() leads vfs calling into this func. So
call blkdev_put() outside of device_list_mutex, as of now.

[  983.284212] ======================================================
[  983.290401] [ INFO: possible circular locking dependency detected ]
[  983.296677] 4.8.0-rc5-ceph-00023-g1b39cec2 #1 Not tainted
[  983.302081] -------------------------------------------------------
[  983.308357] umount/21720 is trying to acquire lock:
[  983.313243]  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff9128ec51>] blkdev_put+0x31/0x150
[  983.321264]
[  983.321264] but task is already holding lock:
[  983.327101]  (&fs_devs->device_list_mutex){+.+...}, at: [<ffffffffc033d6f6>] __btrfs_close_devices+0x46/0x200 [btrfs]
[  983.337839]
[  983.337839] which lock already depends on the new lock.
[  983.337839]
[  983.346024]
[  983.346024] the existing dependency chain (in reverse order) is:
[  983.353512]
-> #4 (&fs_devs->device_list_mutex){+.+...}:
[  983.359096]        [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.365143]        [<ffffffff91823125>] mutex_lock_nested+0x65/0x350
[  983.371521]        [<ffffffffc02d8116>] btrfs_show_devname+0x36/0x1f0 [btrfs]
[  983.378710]        [<ffffffff9129523e>] show_vfsmnt+0x4e/0x150
[  983.384593]        [<ffffffff9126ffc7>] m_show+0x17/0x20
[  983.389957]        [<ffffffff91276405>] seq_read+0x2b5/0x3b0
[  983.395669]        [<ffffffff9124c808>] __vfs_read+0x28/0x100
[  983.401464]        [<ffffffff9124eb3b>] vfs_read+0xab/0x150
[  983.407080]        [<ffffffff9124ec32>] SyS_read+0x52/0xb0
[  983.412609]        [<ffffffff91825fc0>] entry_SYSCALL_64_fastpath+0x23/0xc1
[  983.419617]
-> #3 (namespace_sem){++++++}:
[  983.424024]        [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.430074]        [<ffffffff918239e9>] down_write+0x49/0x80
[  983.435785]        [<ffffffff91272457>] lock_mount+0x67/0x1c0
[  983.441582]        [<ffffffff91272ab2>] do_add_mount+0x32/0xf0
[  983.447458]        [<ffffffff9127363a>] finish_automount+0x5a/0xc0
[  983.453682]        [<ffffffff91259513>] follow_managed+0x1b3/0x2a0
[  983.459912]        [<ffffffff9125b750>] lookup_fast+0x300/0x350
[  983.465875]        [<ffffffff9125d6e7>] path_openat+0x3a7/0xaa0
[  983.471846]        [<ffffffff9125ef75>] do_filp_open+0x85/0xe0
[  983.477731]        [<ffffffff9124c41c>] do_sys_open+0x14c/0x1f0
[  983.483702]        [<ffffffff9124c4de>] SyS_open+0x1e/0x20
[  983.489240]        [<ffffffff91825fc0>] entry_SYSCALL_64_fastpath+0x23/0xc1
[  983.496254]
-> #2 (&sb->s_type->i_mutex_key#3){+.+.+.}:
[  983.501798]        [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.507855]        [<ffffffff918239e9>] down_write+0x49/0x80
[  983.513558]        [<ffffffff91366237>] start_creating+0x87/0x100
[  983.519703]        [<ffffffff91366647>] debugfs_create_dir+0x17/0x100
[  983.526195]        [<ffffffff911df153>] bdi_register+0x93/0x210
[  983.532165]        [<ffffffff911df313>] bdi_register_owner+0x43/0x70
[  983.538570]        [<ffffffff914080fb>] device_add_disk+0x1fb/0x450
[  983.544888]        [<ffffffff91580226>] loop_add+0x1e6/0x290
[  983.550596]        [<ffffffff91fec358>] loop_init+0x10b/0x14f
[  983.556394]        [<ffffffff91002207>] do_one_initcall+0xa7/0x180
[  983.562618]        [<ffffffff91f932e0>] kernel_init_freeable+0x1cc/0x266
[  983.569370]        [<ffffffff918174be>] kernel_init+0xe/0x100
[  983.575166]        [<ffffffff9182620f>] ret_from_fork+0x1f/0x40
[  983.581131]
-> #1 (loop_index_mutex){+.+.+.}:
[  983.585801]        [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.591858]        [<ffffffff91823125>] mutex_lock_nested+0x65/0x350
[  983.598256]        [<ffffffff9157ed3f>] lo_open+0x1f/0x60
[  983.603704]        [<ffffffff9128eec3>] __blkdev_get+0x123/0x400
[  983.609757]        [<ffffffff9128f4ea>] blkdev_get+0x34a/0x350
[  983.615639]        [<ffffffff9128f554>] blkdev_open+0x64/0x80
[  983.621428]        [<ffffffff9124aff6>] do_dentry_open+0x1c6/0x2d0
[  983.627651]        [<ffffffff9124c029>] vfs_open+0x69/0x80
[  983.633181]        [<ffffffff9125db74>] path_openat+0x834/0xaa0
[  983.639152]        [<ffffffff9125ef75>] do_filp_open+0x85/0xe0
[  983.645035]        [<ffffffff9124c41c>] do_sys_open+0x14c/0x1f0
[  983.650999]        [<ffffffff9124c4de>] SyS_open+0x1e/0x20
[  983.656535]        [<ffffffff91825fc0>] entry_SYSCALL_64_fastpath+0x23/0xc1
[  983.663541]
-> #0 (&bdev->bd_mutex){+.+.+.}:
[  983.668107]        [<ffffffff910def43>] __lock_acquire+0x1003/0x17b0
[  983.674510]        [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.680561]        [<ffffffff91823125>] mutex_lock_nested+0x65/0x350
[  983.686967]        [<ffffffff9128ec51>] blkdev_put+0x31/0x150
[  983.692761]        [<ffffffffc033481f>] btrfs_close_bdev+0x4f/0x60 [btrfs]
[  983.699699]        [<ffffffffc033d77b>] __btrfs_close_devices+0xcb/0x200 [btrfs]
[  983.707178]        [<ffffffffc033d8db>] btrfs_close_devices+0x2b/0xa0 [btrfs]
[  983.714380]        [<ffffffffc03081c5>] close_ctree+0x265/0x340 [btrfs]
[  983.721061]        [<ffffffffc02d7959>] btrfs_put_super+0x19/0x20 [btrfs]
[  983.727908]        [<ffffffff91250e2f>] generic_shutdown_super+0x6f/0x100
[  983.734744]        [<ffffffff91250f56>] kill_anon_super+0x16/0x30
[  983.740888]        [<ffffffffc02da97e>] btrfs_kill_super+0x1e/0x130 [btrfs]
[  983.747909]        [<ffffffff91250fe9>] deactivate_locked_super+0x49/0x80
[  983.754745]        [<ffffffff912515fd>] deactivate_super+0x5d/0x70
[  983.760977]        [<ffffffff91270a1c>] cleanup_mnt+0x5c/0x80
[  983.766773]        [<ffffffff91270a92>] __cleanup_mnt+0x12/0x20
[  983.772738]        [<ffffffff910aa2fe>] task_work_run+0x7e/0xc0
[  983.778708]        [<ffffffff91081b5a>] exit_to_usermode_loop+0x7e/0xb4
[  983.785373]        [<ffffffff910039eb>] syscall_return_slowpath+0xbb/0xd0
[  983.792212]        [<ffffffff9182605c>] entry_SYSCALL_64_fastpath+0xbf/0xc1
[  983.799225]
[  983.799225] other info that might help us debug this:
[  983.799225]
[  983.807291] Chain exists of:
  &bdev->bd_mutex --> namespace_sem --> &fs_devs->device_list_mutex

[  983.816521]  Possible unsafe locking scenario:
[  983.816521]
[  983.822489]        CPU0                    CPU1
[  983.827043]        ----                    ----
[  983.831599]   lock(&fs_devs->device_list_mutex);
[  983.836289]                                lock(namespace_sem);
[  983.842268]                                lock(&fs_devs->device_list_mutex);
[  983.849478]   lock(&bdev->bd_mutex);
[  983.853127]
[  983.853127]  *** DEADLOCK ***
[  983.853127]
[  983.859113] 3 locks held by umount/21720:
[  983.863145]  #0:  (&type->s_umount_key#35){++++..}, at: [<ffffffff912515f5>] deactivate_super+0x55/0x70
[  983.872713]  #1:  (uuid_mutex){+.+.+.}, at: [<ffffffffc033d8d3>] btrfs_close_devices+0x23/0xa0 [btrfs]
[  983.882206]  #2:  (&fs_devs->device_list_mutex){+.+...}, at: [<ffffffffc033d6f6>] __btrfs_close_devices+0x46/0x200 [btrfs]
[  983.893422]
[  983.893422] stack backtrace:
[  983.897824] CPU: 6 PID: 21720 Comm: umount Not tainted 4.8.0-rc5-ceph-00023-g1b39cec2 #1
[  983.905958] Hardware name: Supermicro SYS-5018R-WR/X10SRW-F, BIOS 1.0c 09/07/2015
[  983.913492]  0000000000000000 ffff8c8a53c17a38 ffffffff91429521 ffffffff9260f4f0
[  983.921018]  ffffffff92642760 ffff8c8a53c17a88 ffffffff911b2b04 0000000000000050
[  983.928542]  ffffffff9237d620 ffff8c8a5294aee0 ffff8c8a5294aeb8 ffff8c8a5294aee0
[  983.936072] Call Trace:
[  983.938545]  [<ffffffff91429521>] dump_stack+0x85/0xc4
[  983.943715]  [<ffffffff911b2b04>] print_circular_bug+0x1fb/0x20c
[  983.949748]  [<ffffffff910def43>] __lock_acquire+0x1003/0x17b0
[  983.955613]  [<ffffffff910dfd0c>] lock_acquire+0x1bc/0x1f0
[  983.961123]  [<ffffffff9128ec51>] ? blkdev_put+0x31/0x150
[  983.966550]  [<ffffffff91823125>] mutex_lock_nested+0x65/0x350
[  983.972407]  [<ffffffff9128ec51>] ? blkdev_put+0x31/0x150
[  983.977832]  [<ffffffff9128ec51>] blkdev_put+0x31/0x150
[  983.983101]  [<ffffffffc033481f>] btrfs_close_bdev+0x4f/0x60 [btrfs]
[  983.989500]  [<ffffffffc033d77b>] __btrfs_close_devices+0xcb/0x200 [btrfs]
[  983.996415]  [<ffffffffc033d8db>] btrfs_close_devices+0x2b/0xa0 [btrfs]
[  984.003068]  [<ffffffffc03081c5>] close_ctree+0x265/0x340 [btrfs]
[  984.009189]  [<ffffffff9126cc5e>] ? evict_inodes+0x15e/0x170
[  984.014881]  [<ffffffffc02d7959>] btrfs_put_super+0x19/0x20 [btrfs]
[  984.021176]  [<ffffffff91250e2f>] generic_shutdown_super+0x6f/0x100
[  984.027476]  [<ffffffff91250f56>] kill_anon_super+0x16/0x30
[  984.033082]  [<ffffffffc02da97e>] btrfs_kill_super+0x1e/0x130 [btrfs]
[  984.039548]  [<ffffffff91250fe9>] deactivate_locked_super+0x49/0x80
[  984.045839]  [<ffffffff912515fd>] deactivate_super+0x5d/0x70
[  984.051525]  [<ffffffff91270a1c>] cleanup_mnt+0x5c/0x80
[  984.056774]  [<ffffffff91270a92>] __cleanup_mnt+0x12/0x20
[  984.062201]  [<ffffffff910aa2fe>] task_work_run+0x7e/0xc0
[  984.067625]  [<ffffffff91081b5a>] exit_to_usermode_loop+0x7e/0xb4
[  984.073747]  [<ffffffff910039eb>] syscall_return_slowpath+0xbb/0xd0
[  984.080038]  [<ffffffff9182605c>] entry_SYSCALL_64_fastpath+0xbf/0xc1
Reported-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The extent buffer 'next' needs to be free'd conditionally.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We can hit unused variable warnings when btrfs_debug and friends are
just aliases for no_printk.  This is due to the fs_info not getting
consumed by the function call, which can happen if convenenience
variables are used.  This patch adds a new btrfs_no_printk static inline
that consumes the convenience variable and does nothing else.  It
silences the unused variable warning and has no impact on the generated
code:

$ size fs/btrfs/extent_io.o*
   text	   data	    bss	    dec	    hex	filename
  44072	    152	     32	  44256	   ace0	fs/btrfs/extent_io.o.btrfs_no_printk
  44072	    152	     32	  44256	   ace0	fs/btrfs/extent_io.o.no_printk

Fixes: 27a0dd61 (Btrfs: make btrfs_debug match pr_debug handling related to DEBUG)
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This was basically an open-coded, less flexible dynamic printk.  We can
just use btrfs_debug instead.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

For many printks, we want to know which file system issued the message.

This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.

fs/btrfs/check-integrity.c is left alone for another day.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This patch converts printk(KERN_* style messages to use the pr_* versions.

One side effect is that anything that was KERN_DEBUG is now automatically
a dynamic debug message.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."

This patch unsplits user-visible strings.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>