We can preallocate the node so insertion does not have to do that under
the lock. The GFP flags for the global radix tree are initialized to
 GFP_NOFS & ~__GFP_DIRECT_RECLAIM
but we can use GFP_KERNEL, because readahead is optional and not on any
critical writeout path.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Using an int value is causing qg->reserved to become negative and
exclusive -EDQUOT to be reached prematurely.

This affects exclusive qgroups only.

TEST CASE:

DEVICE=/dev/vdb
MOUNTPOINT=/mnt
SUBVOL=$MOUNTPOINT/tmp

umount $SUBVOL
umount $MOUNTPOINT

mkfs.btrfs -f $DEVICE
mount /dev/vdb $MOUNTPOINT
btrfs quota enable $MOUNTPOINT
btrfs subvol create $SUBVOL
umount $MOUNTPOINT
mount /dev/vdb $MOUNTPOINT
mount -o subvol=tmp $DEVICE $SUBVOL
btrfs qgroup limit -e 3G $SUBVOL

btrfs quota rescan /mnt -w

for i in `seq 1 44000`; do
  dd if=/dev/zero of=/mnt/tmp/test_$i bs=10k count=1
  if [[ $? > 0 ]]; then
     btrfs qgroup show -pcref $SUBVOL
     exit 1
  fi
done
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
[ add reproducer to changelog ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Make extent_io_ops::readpage_io_failed_hook callback mandatory and
define a dummy function for btrfs_extent_io_ops. As the failed IO
callback is not performance critical, the branch vs extra trade off does
not hurt.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Some of the callbacks defined in btree_extent_io_ops and
btrfs_extent_io_ops do always exist so we don't need to check the
existence before each call. This patch just reorders the definition and
documents which are mandatory/optional.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The function does not modify the input buffer, also update a typecast in
one caller.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In addition to changing the signature, this patch also switches
all the functions which are used as an argument to also take btrfs_inode.
Namely those are: btrfs_get_extent and btrfs_get_extent_filemap.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Before we destroy all work queues (and wait for their tasks to complete)
we were destroying the work queues used for metadata I/O operations, which
can result in a use-after-free problem because most tasks from all work
queues do metadata I/O operations. For example, the tasks from the caching
workers work queue (fs_info->caching_workers), which is destroyed only
after the work queue used for metadata reads (fs_info->endio_meta_workers)
is destroyed, do metadata reads, which result in attempts to queue tasks
into the later work queue, triggering a use-after-free with a trace like
the following:

[23114.613543] general protection fault: 0000 [#1] PREEMPT SMP
[23114.614442] Modules linked in: dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c btrfs xor raid6_pq dm_flakey dm_mod crc32c_generic
acpi_cpufreq tpm_tis tpm_tis_core tpm ppdev parport_pc parport i2c_piix4 processor sg evdev i2c_core psmouse pcspkr serio_raw button loop autofs4 ext4 crc16
jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio e1000 scsi_mod floppy [last unloaded: scsi_debug]
[23114.616932] CPU: 9 PID: 4537 Comm: kworker/u32:8 Not tainted 4.9.0-rc7-btrfs-next-36+ #1
[23114.616932] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[23114.616932] Workqueue: btrfs-cache btrfs_cache_helper [btrfs]
[23114.616932] task: ffff880221d45780 task.stack: ffffc9000bc50000
[23114.616932] RIP: 0010:[<ffffffffa037c1bf>]  [<ffffffffa037c1bf>] btrfs_queue_work+0x2c/0x190 [btrfs]
[23114.616932] RSP: 0018:ffff88023f443d60  EFLAGS: 00010246
[23114.616932] RAX: 0000000000000000 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000102
[23114.616932] RDX: ffffffffa0419000 RSI: ffff88011df534f0 RDI: ffff880101f01c00
[23114.616932] RBP: ffff88023f443d80 R08: 00000000000f7000 R09: 000000000000ffff
[23114.616932] R10: ffff88023f443d48 R11: 0000000000001000 R12: ffff88011df534f0
[23114.616932] R13: ffff880135963868 R14: 0000000000001000 R15: 0000000000001000
[23114.616932] FS:  0000000000000000(0000) GS:ffff88023f440000(0000) knlGS:0000000000000000
[23114.616932] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[23114.616932] CR2: 00007f0fb9f8e520 CR3: 0000000001a0b000 CR4: 00000000000006e0
[23114.616932] Stack:
[23114.616932]  ffff880101f01c00 ffff88011df534f0 ffff880135963868 0000000000001000
[23114.616932]  ffff88023f443da0 ffffffffa03470af ffff880149b37200 ffff880135963868
[23114.616932]  ffff88023f443db8 ffffffff8125293c ffff880149b37200 ffff88023f443de0
[23114.616932] Call Trace:
[23114.616932]  <IRQ> [23114.616932]  [<ffffffffa03470af>] end_workqueue_bio+0xd5/0xda [btrfs]
[23114.616932]  [<ffffffff8125293c>] bio_endio+0x54/0x57
[23114.616932]  [<ffffffffa0377929>] btrfs_end_bio+0xf7/0x106 [btrfs]
[23114.616932]  [<ffffffff8125293c>] bio_endio+0x54/0x57
[23114.616932]  [<ffffffff8125955f>] blk_update_request+0x21a/0x30f
[23114.616932]  [<ffffffffa0022316>] scsi_end_request+0x31/0x182 [scsi_mod]
[23114.616932]  [<ffffffffa00235fc>] scsi_io_completion+0x1ce/0x4c8 [scsi_mod]
[23114.616932]  [<ffffffffa001ba9d>] scsi_finish_command+0x104/0x10d [scsi_mod]
[23114.616932]  [<ffffffffa002311f>] scsi_softirq_done+0x101/0x10a [scsi_mod]
[23114.616932]  [<ffffffff8125fbd9>] blk_done_softirq+0x82/0x8d
[23114.616932]  [<ffffffff814c8a4b>] __do_softirq+0x1ab/0x412
[23114.616932]  [<ffffffff8105b01d>] irq_exit+0x49/0x99
[23114.616932]  [<ffffffff81035135>] smp_call_function_single_interrupt+0x24/0x26
[23114.616932]  [<ffffffff814c7ec9>] call_function_single_interrupt+0x89/0x90
[23114.616932]  <EOI> [23114.616932]  [<ffffffffa0023262>] ? scsi_request_fn+0x13a/0x2a1 [scsi_mod]
[23114.616932]  [<ffffffff814c5966>] ? _raw_spin_unlock_irq+0x2c/0x4a
[23114.616932]  [<ffffffff814c596c>] ? _raw_spin_unlock_irq+0x32/0x4a
[23114.616932]  [<ffffffff814c5966>] ? _raw_spin_unlock_irq+0x2c/0x4a
[23114.616932]  [<ffffffffa0023262>] scsi_request_fn+0x13a/0x2a1 [scsi_mod]
[23114.616932]  [<ffffffff8125590e>] __blk_run_queue_uncond+0x22/0x2b
[23114.616932]  [<ffffffff81255930>] __blk_run_queue+0x19/0x1b
[23114.616932]  [<ffffffff8125ab01>] blk_queue_bio+0x268/0x282
[23114.616932]  [<ffffffff81258f44>] generic_make_request+0xbd/0x160
[23114.616932]  [<ffffffff812590e7>] submit_bio+0x100/0x11d
[23114.616932]  [<ffffffff81298603>] ? __this_cpu_preempt_check+0x13/0x15
[23114.616932]  [<ffffffff812a1805>] ? __percpu_counter_add+0x8e/0xa7
[23114.616932]  [<ffffffffa03bfd47>] btrfsic_submit_bio+0x1a/0x1d [btrfs]
[23114.616932]  [<ffffffffa0377db2>] btrfs_map_bio+0x1f4/0x26d [btrfs]
[23114.616932]  [<ffffffffa0348a33>] btree_submit_bio_hook+0x74/0xbf [btrfs]
[23114.616932]  [<ffffffffa03489bf>] ? btrfs_wq_submit_bio+0x160/0x160 [btrfs]
[23114.616932]  [<ffffffffa03697a9>] submit_one_bio+0x6b/0x89 [btrfs]
[23114.616932]  [<ffffffffa036f5be>] read_extent_buffer_pages+0x170/0x1ec [btrfs]
[23114.616932]  [<ffffffffa03471fa>] ? free_root_pointers+0x64/0x64 [btrfs]
[23114.616932]  [<ffffffffa0348adf>] readahead_tree_block+0x3f/0x4c [btrfs]
[23114.616932]  [<ffffffffa032e115>] read_block_for_search.isra.20+0x1ce/0x23d [btrfs]
[23114.616932]  [<ffffffffa032fab8>] btrfs_search_slot+0x65f/0x774 [btrfs]
[23114.616932]  [<ffffffffa036eff1>] ? free_extent_buffer+0x73/0x7e [btrfs]
[23114.616932]  [<ffffffffa0331ba4>] btrfs_next_old_leaf+0xa1/0x33c [btrfs]
[23114.616932]  [<ffffffffa0331e4f>] btrfs_next_leaf+0x10/0x12 [btrfs]
[23114.616932]  [<ffffffffa0336aa6>] caching_thread+0x22d/0x416 [btrfs]
[23114.616932]  [<ffffffffa037bce9>] btrfs_scrubparity_helper+0x187/0x3b6 [btrfs]
[23114.616932]  [<ffffffffa037c036>] btrfs_cache_helper+0xe/0x10 [btrfs]
[23114.616932]  [<ffffffff8106cf96>] process_one_work+0x273/0x4e4
[23114.616932]  [<ffffffff8106d6db>] worker_thread+0x1eb/0x2ca
[23114.616932]  [<ffffffff8106d4f0>] ? rescuer_thread+0x2b6/0x2b6
[23114.616932]  [<ffffffff81072a81>] kthread+0xd5/0xdd
[23114.616932]  [<ffffffff810729ac>] ? __kthread_unpark+0x5a/0x5a
[23114.616932]  [<ffffffff814c6257>] ret_from_fork+0x27/0x40
[23114.616932] Code: 1f 44 00 00 55 48 89 e5 41 56 41 55 41 54 53 49 89 f4 48 8b 46 70 a8 04 74 09 48 8b 5f 08 48 85 db 75 03 48 8b 1f 49 89 5c 24 68 <83> 7b
64 ff 74 04 f0 ff 43 58 49 83 7c 24 08 00 74 2c 4c 8d 6b
[23114.616932] RIP  [<ffffffffa037c1bf>] btrfs_queue_work+0x2c/0x190 [btrfs]
[23114.616932]  RSP <ffff88023f443d60>
[23114.689493] ---[ end trace 6e48b6bc707ca34b ]---
[23114.690166] Kernel panic - not syncing: Fatal exception in interrupt
[23114.691283] Kernel Offset: disabled
[23114.691918] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

The following diagram shows the sequence of operations that lead to the
use-after-free problem from the above trace:

        CPU 1                               CPU 2                                     CPU 3

                                       caching_thread()
 close_ctree()
   btrfs_stop_all_workers()
     btrfs_destroy_workqueue(
      fs_info->endio_meta_workers)

                                         btrfs_search_slot()
                                          read_block_for_search()
                                           readahead_tree_block()
                                            read_extent_buffer_pages()
                                             submit_one_bio()
                                              btree_submit_bio_hook()
                                               btrfs_bio_wq_end_io()
                                                --> sets the bio's
                                                    bi_end_io callback
                                                    to end_workqueue_bio()
                                               --> bio is submitted
                                                                                  bio completes
                                                                                  and its bi_end_io callback
                                                                                  is invoked
                                                                                   --> end_workqueue_bio()
                                                                                       --> attempts to queue
                                                                                           a task on fs_info->endio_meta_workers

     btrfs_destroy_workqueue(
      fs_info->caching_workers)

So fix this by destroying the queues used for metadata I/O tasks only
after destroying all the other queues.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>

At close_ctree() we free the block groups and then only after we wait for
any running worker kthreads to finish and shutdown the workqueues. This
behaviour is racy and it triggers an assertion failure when freeing block
groups because while we are doing it we can have for example a block group
caching kthread running, and in that case the block group's reference
count can still be greater than 1 by the time we assert its reference count
is 1, leading to an assertion failure:

[19041.198004] assertion failed: atomic_read(&block_group->count) == 1, file: fs/btrfs/extent-tree.c, line: 9799
[19041.200584] ------------[ cut here ]------------
[19041.201692] kernel BUG at fs/btrfs/ctree.h:3418!
[19041.202830] invalid opcode: 0000 [#1] PREEMPT SMP
[19041.203929] Modules linked in: btrfs xor raid6_pq dm_flakey dm_mod crc32c_generic ppdev sg psmouse acpi_cpufreq pcspkr parport_pc evdev tpm_tis parport tpm_tis_core i2c_piix4 i2c_core tpm serio_raw processor button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio e1000 scsi_mod floppy [last unloaded: btrfs]
[19041.208082] CPU: 6 PID: 29051 Comm: umount Not tainted 4.9.0-rc7-btrfs-next-36+ #1
[19041.208082] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[19041.208082] task: ffff88015f028980 task.stack: ffffc9000ad34000
[19041.208082] RIP: 0010:[<ffffffffa03e319e>]  [<ffffffffa03e319e>] assfail.constprop.41+0x1c/0x1e [btrfs]
[19041.208082] RSP: 0018:ffffc9000ad37d60  EFLAGS: 00010286
[19041.208082] RAX: 0000000000000061 RBX: ffff88015ecb4000 RCX: 0000000000000001
[19041.208082] RDX: ffff88023f392fb8 RSI: ffffffff817ef7ba RDI: 00000000ffffffff
[19041.208082] RBP: ffffc9000ad37d60 R08: 0000000000000001 R09: 0000000000000000
[19041.208082] R10: ffffc9000ad37cb0 R11: ffffffff82f2b66d R12: ffff88023431d170
[19041.208082] R13: ffff88015ecb40c0 R14: ffff88023431d000 R15: ffff88015ecb4100
[19041.208082] FS:  00007f44f3d42840(0000) GS:ffff88023f380000(0000) knlGS:0000000000000000
[19041.208082] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[19041.208082] CR2: 00007f65d623b000 CR3: 00000002166f2000 CR4: 00000000000006e0
[19041.208082] Stack:
[19041.208082]  ffffc9000ad37d98 ffffffffa035989f ffff88015ecb4000 ffff88015ecb5630
[19041.208082]  ffff88014f6be000 0000000000000000 00007ffcf0ba6a10 ffffc9000ad37df8
[19041.208082]  ffffffffa0368cd4 ffff88014e9658e0 ffffc9000ad37e08 ffffffff811a634d
[19041.208082] Call Trace:
[19041.208082]  [<ffffffffa035989f>] btrfs_free_block_groups+0x17f/0x392 [btrfs]
[19041.208082]  [<ffffffffa0368cd4>] close_ctree+0x1c5/0x2e1 [btrfs]
[19041.208082]  [<ffffffff811a634d>] ? evict_inodes+0x132/0x141
[19041.208082]  [<ffffffffa034356d>] btrfs_put_super+0x15/0x17 [btrfs]
[19041.208082]  [<ffffffff8118fc32>] generic_shutdown_super+0x6a/0xeb
[19041.208082]  [<ffffffff8119004f>] kill_anon_super+0x12/0x1c
[19041.208082]  [<ffffffffa0343370>] btrfs_kill_super+0x16/0x21 [btrfs]
[19041.208082]  [<ffffffff8118fad1>] deactivate_locked_super+0x3b/0x68
[19041.208082]  [<ffffffff8118fb34>] deactivate_super+0x36/0x39
[19041.208082]  [<ffffffff811a9946>] cleanup_mnt+0x58/0x76
[19041.208082]  [<ffffffff811a99a2>] __cleanup_mnt+0x12/0x14
[19041.208082]  [<ffffffff81071573>] task_work_run+0x6f/0x95
[19041.208082]  [<ffffffff81001897>] prepare_exit_to_usermode+0xa3/0xc1
[19041.208082]  [<ffffffff81001a23>] syscall_return_slowpath+0x16e/0x1d2
[19041.208082]  [<ffffffff814c607d>] entry_SYSCALL_64_fastpath+0xab/0xad
[19041.208082] Code: c7 ae a0 3e a0 48 89 e5 e8 4e 74 d4 e0 0f 0b 55 89 f1 48 c7 c2 0b a4 3e a0 48 89 fe 48 c7 c7 a4 a6 3e a0 48 89 e5 e8 30 74 d4 e0 <0f> 0b 55 31 d2 48 89 e5 e8 d5 b9 f7 ff 5d c3 48 63 f6 55 31 c9
[19041.208082] RIP  [<ffffffffa03e319e>] assfail.constprop.41+0x1c/0x1e [btrfs]
[19041.208082]  RSP <ffffc9000ad37d60>
[19041.279264] ---[ end trace 23330586f16f064d ]---

This started happening as of kernel 4.8, since commit f3bca802
("Btrfs: add ASSERT for block group's memory leak") introduced these
assertions.

So fix this by freeing the block groups only after waiting for all
worker kthreads to complete and shutdown the workqueues.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>

None of the checks need to know the ro/rw status as they're all not
changing the superblock. Moreover, we can access the sb flags directly
if we'd need to decide by the ro/rw status.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

write_all_supers and write_ctree_super are almost equal, the parameter
'trans' is unused so we can drop it and have just one helper.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The barriers are handled by the caller.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Added but never needed.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Added but never used.
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

blk_get_backing_dev_info() is now a simple dereference. Remove that
function and simplify some code around that.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

The helpers are trivial and we don't use them consistently.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Now we only use the root parameter to print the root objectid in
a tracepoint.  We can use the root parameter from the transaction
handle for that.  It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer.  Let's convert those to
just accept an fs_info pointer directly.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This results in btrfs_assert_delayed_root_empty and
btrfs_destroy_delayed_inode taking an fs_info instead of a root.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable.  This makes the code considerably
more readable.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We track the node sizes per-root, but they never vary from the values
in the superblock.  This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are many functions that are always called with the same root
argument.  Rather than passing the same root every time, we can
pass an fs_info pointer instead and have the function get the root
pointer itself.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are 11 functions that accept a root parameter and immediately
overwrite it.  We can pass those an fs_info pointer instead.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This issue was found when I tried to delete a heavily reflinked file,
when deleting such files, other transaction operation will not have a
chance to make progress, for example, start_transaction() will blocked
in wait_current_trans(root) for long time, sometimes it even triggers
soft lockups, and the time taken to delete such heavily reflinked file
is also very large, often hundreds of seconds. Using perf top, it reports
that:

PerfTop:    7416 irqs/sec  kernel:99.8%  exact:  0.0% [4000Hz cpu-clock],  (all, 4 CPUs)
---------------------------------------------------------------------------------------
    84.37%  [btrfs]             [k] __btrfs_run_delayed_refs.constprop.80
    11.02%  [kernel]            [k] delay_tsc
     0.79%  [kernel]            [k] _raw_spin_unlock_irq
     0.78%  [kernel]            [k] _raw_spin_unlock_irqrestore
     0.45%  [kernel]            [k] do_raw_spin_lock
     0.18%  [kernel]            [k] __slab_alloc
It seems __btrfs_run_delayed_refs() took most cpu time, after some debug
work, I found it's select_delayed_ref() causing this issue, for a delayed
head, in our case, it'll be full of BTRFS_DROP_DELAYED_REF nodes, but
select_delayed_ref() will firstly try to iterate node list to find
BTRFS_ADD_DELAYED_REF nodes, obviously it's a disaster in this case, and
waste much time.

To fix this issue, we introduce a new ref_add_list in struct btrfs_delayed_ref_head,
then in select_delayed_ref(), if this list is not empty, we can directly use
nodes in this list. With this patch, it just took about 10~15 seconds to
delte the same file. Now using perf top, it reports that:

PerfTop:    2734 irqs/sec  kernel:99.5%  exact:  0.0% [4000Hz cpu-clock],  (all, 4 CPUs)
----------------------------------------------------------------------------------------

    20.74%  [kernel]          [k] _raw_spin_unlock_irqrestore
    16.33%  [kernel]          [k] __slab_alloc
     5.41%  [kernel]          [k] lock_acquired
     4.42%  [kernel]          [k] lock_acquire
     4.05%  [kernel]          [k] lock_release
     3.37%  [kernel]          [k] _raw_spin_unlock_irq

For normal files, this patch also gives help, at least we do not need to
iterate whole list to found BTRFS_ADD_DELAYED_REF nodes.
Signed-off-by: NWang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Tested-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

csum member of struct btrfs_super_block has array type of u8. It makes
sense that function btrfs_csum_final should be also declared to accept
u8 *. I changed the declaration of method void btrfs_csum_final(u32 crc,
char *result); to void btrfs_csum_final(u32 crc, u8 *result);
Signed-off-by: NDomagoj Tršan <domagoj.trsan@gmail.com>
[ changed cast to u8 at several call sites ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The only memset we do is to 0, so sink the parameter to the function and
simplify all calls. Rename the function to reflect the behaviour.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NDavid Sterba <dsterba@suse.com>

During the time, the function has been shrunk to the point that it just
calls find_extent_buffer, just passing the parameters.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Originally, the eb and start were passed separately in case eb is NULL.
Since the readahead has been refactored in 4.6, this is not true anymore
and we can get rid of the parameter.
Signed-off-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>

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.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>

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>