It really wants btrfs_inode and not a vfs inode.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

It doesn't use the generic vfs inode for anything use btrfs_inode
directly.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

It doesn't use the vfs inode for anything, can just as easily take
btrfs_inode.  Follow up patches will convert callers as well.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

[BUG]
The following simple workload from fsstress can lead to qgroup reserved
data space leak:
  0/0: creat f0 x:0 0 0
  0/0: creat add id=0,parent=-1
  0/1: write f0[259 1 0 0 0 0] [600030,27288] 0
  0/4: dwrite - xfsctl(XFS_IOC_DIOINFO) f0[259 1 0 0 64 627318] return 25, fallback to stat()
  0/4: dwrite f0[259 1 0 0 64 627318] [610304,106496] 0

This would cause btrfs qgroup to leak 20480 bytes for data reserved
space.  If btrfs qgroup limit is enabled, such leak can lead to
unexpected early EDQUOT and unusable space.

[CAUSE]
When doing direct IO, kernel will try to writeback existing buffered
page cache, then invalidate them:
  generic_file_direct_write()
  |- filemap_write_and_wait_range();
  |- invalidate_inode_pages2_range();

However for btrfs, the bi_end_io hook doesn't finish all its heavy work
right after bio ends.  In fact, it delays its work further:

  submit_extent_page(end_io_func=end_bio_extent_writepage);
  end_bio_extent_writepage()
  |- btrfs_writepage_endio_finish_ordered()
     |- btrfs_init_work(finish_ordered_fn);

  <<< Work queue execution >>>
  finish_ordered_fn()
  |- btrfs_finish_ordered_io();
     |- Clear qgroup bits

This means, when filemap_write_and_wait_range() returns,
btrfs_finish_ordered_io() is not guaranteed to be executed, thus the
qgroup bits for related range are not cleared.

Now into how the leak happens, this will only focus on the overlapping
part of buffered and direct IO part.

1. After buffered write
   The inode had the following range with QGROUP_RESERVED bit:
   	596		616K
	|///////////////|
   Qgroup reserved data space: 20K

2. Writeback part for range [596K, 616K)
   Write back finished, but btrfs_finish_ordered_io() not get called
   yet.
   So we still have:
   	596K		616K
	|///////////////|
   Qgroup reserved data space: 20K

3. Pages for range [596K, 616K) get released
   This will clear all qgroup bits, but don't update the reserved data
   space.
   So we have:
   	596K		616K
	|		|
   Qgroup reserved data space: 20K
   That number doesn't match the qgroup bit range anymore.

4. Dio prepare space for range [596K, 700K)
   Qgroup reserved data space for that range, we got:
   	596K		616K			700K
	|///////////////|///////////////////////|
   Qgroup reserved data space: 20K + 104K = 124K

5. btrfs_finish_ordered_range() gets executed for range [596K, 616K)
   Qgroup free reserved space for that range, we got:
   	596K		616K			700K
	|		|///////////////////////|
   We need to free that range of reserved space.
   Qgroup reserved data space: 124K - 20K = 104K

6. btrfs_finish_ordered_range() gets executed for range [596K, 700K)
   However qgroup bit for range [596K, 616K) is already cleared in
   previous step, so we only free 84K for qgroup reserved space.
   	596K		616K			700K
	|		|			|
   We need to free that range of reserved space.
   Qgroup reserved data space: 104K - 84K = 20K

   Now there is no way to release that 20K unless disabling qgroup or
   unmounting the fs.

[FIX]
This patch will change the timing of btrfs_qgroup_release/free_data()
call.  Here it uses buffered COW write as an example.

	The new timing			|	The old timing
----------------------------------------+---------------------------------------
 btrfs_buffered_write()			| btrfs_buffered_write()
 |- btrfs_qgroup_reserve_data() 	| |- btrfs_qgroup_reserve_data()
					|
 btrfs_run_delalloc_range()		| btrfs_run_delalloc_range()
 |- btrfs_add_ordered_extent()  	|
    |- btrfs_qgroup_release_data()	|
       The reserved is passed into	|
       btrfs_ordered_extent structure	|
					|
 btrfs_finish_ordered_io()		| btrfs_finish_ordered_io()
 |- The reserved space is passed to 	| |- btrfs_qgroup_release_data()
    btrfs_qgroup_record			|    The resereved space is passed
					|    to btrfs_qgroup_recrod
					|
 btrfs_qgroup_account_extents()		| btrfs_qgroup_account_extents()
 |- btrfs_qgroup_free_refroot()		| |- btrfs_qgroup_free_refroot()

The point of such change is to ensure, when ordered extents are
submitted, the qgroup reserved space is already released, to keep the
timing aligned with file_write_and_wait_range().

So that qgroup data reserved space is all bound to btrfs_ordered_extent
and solve the timing mismatch.

Fixes: f695fdce ("btrfs: qgroup: Introduce functions to release/free qgroup reserve data space")
Suggested-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is to prepare for the incoming timing change of qgroup reserved
data space and ordered extent.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Function insert_reserved_file_extent() takes a long list of parameters,
which are all for btrfs_file_extent_item, even including two reserved
members, encryption and other_encoding.

This makes the parameter list unnecessary long for a function which only
gets called twice.

This patch will refactor the parameter list, by using
btrfs_file_extent_item as parameter directly to hugely reduce the number
of parameters.

Also, since there are only two callers, one in btrfs_finish_ordered_io()
which inserts file extent for ordered extent, and one
__btrfs_prealloc_file_range().

These two call sites have completely different context, where ordered
extent can be compressed, but will always be regular extent, while the
preallocated one is never going to be compressed and always has PREALLOC
type.

So use two small wrapper for these two different call sites to improve
readability.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The start argument for btrfs_free_reserved_data_space_noquota() is only
used to make sure the amount of bytes we decrement from the bytes_may_use
counter of the data space_info object is aligned to the filesystem's
sector size. It serves no other purpose.

All its current callers always pass a length argument that is already
aligned to the sector size, so we can make the start argument go away.
In fact its presence makes it impossible to use it in a context where we
just want to free a number of bytes for a range for which either we do
not know its start offset or for freeing multiple ranges at once (which
are not contiguous).

This change is preparatory work for a patch (third patch in this series)
that makes relocation of data block groups that are not full reserve less
data space.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

[BUG]
When running tests like generic/013 on test device with btrfs quota
enabled, it can normally lead to data leak, detected at unmount time:

  BTRFS warning (device dm-3): qgroup 0/5 has unreleased space, type 0 rsv 4096
  ------------[ cut here ]------------
  WARNING: CPU: 11 PID: 16386 at fs/btrfs/disk-io.c:4142 close_ctree+0x1dc/0x323 [btrfs]
  RIP: 0010:close_ctree+0x1dc/0x323 [btrfs]
  Call Trace:
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   __prepare_exit_to_usermode+0x1bc/0x1c0
   __syscall_return_slowpath+0x47/0x230
   do_syscall_64+0x64/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace caf08beafeca2392 ]---
  BTRFS error (device dm-3): qgroup reserved space leaked

[CAUSE]
In the offending case, the offending operations are:
2/6: writev f2X[269 1 0 0 0 0] [1006997,67,288] 0
2/7: truncate f2X[269 1 0 0 48 1026293] 18388 0

The following sequence of events could happen after the writev():
	CPU1 (writeback)		|		CPU2 (truncate)
-----------------------------------------------------------------
btrfs_writepages()			|
|- extent_write_cache_pages()		|
   |- Got page for 1003520		|
   |  1003520 is Dirty, no writeback	|
   |  So (!clear_page_dirty_for_io())   |
   |  gets called for it		|
   |- Now page 1003520 is Clean.	|
   |					| btrfs_setattr()
   |					| |- btrfs_setsize()
   |					|    |- truncate_setsize()
   |					|       New i_size is 18388
   |- __extent_writepage()		|
   |  |- page_offset() > i_size		|
      |- btrfs_invalidatepage()		|
	 |- Page is clean, so no qgroup |
	    callback executed

This means, the qgroup reserved data space is not properly released in
btrfs_invalidatepage() as the page is Clean.

[FIX]
Instead of checking the dirty bit of a page, call
btrfs_qgroup_free_data() unconditionally in btrfs_invalidatepage().

As qgroup rsv are completely bound to the QGROUP_RESERVED bit of
io_tree, not bound to page status, thus we won't cause double freeing
anyway.

Fixes: 0b34c261 ("btrfs: qgroup: Prevent qgroup->reserved from going subzero")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

While debugging a patch that I wrote I was hitting use-after-free panics
when accessing block groups on unmount.  This turned out to be because
in the nocow case if we bail out of doing the nocow for whatever reason
we need to call btrfs_dec_nocow_writers() if we called the inc.  This
puts our block group, but a few error cases does

if (nocow) {
    btrfs_dec_nocow_writers();
    goto error;
}

unfortunately, error is

error:
	if (nocow)
		btrfs_dec_nocow_writers();

so we get a double put on our block group.  Fix this by dropping the
error cases calling of btrfs_dec_nocow_writers(), as it's handled at the
error label now.

Fixes: 762bf098 ("btrfs: improve error handling in run_delalloc_nocow")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

If we attempt to write to prealloc extent located after eof using a
RWF_NOWAIT write, we always fail with -EAGAIN.

We do actually check if we have an allocated extent for the write at
the start of btrfs_file_write_iter() through a call to check_can_nocow(),
but later when we go into the actual direct IO write path we simply
return -EAGAIN if the write starts at or beyond EOF.

Trivial to reproduce:

  $ mkfs.btrfs -f /dev/sdb
  $ mount /dev/sdb /mnt

  $ touch /mnt/foo
  $ chattr +C /mnt/foo

  $ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foo
  wrote 65536/65536 bytes at offset 0
  64 KiB, 16 ops; 0.0004 sec (135.575 MiB/sec and 34707.1584 ops/sec)

  $ xfs_io -c "falloc -k 64K 1M" /mnt/foo

  $ xfs_io -d -c "pwrite -N -V 1 -S 0xfe -b 64K 64K 64K" /mnt/foo
  pwrite: Resource temporarily unavailable

On xfs and ext4 the write succeeds, as expected.

Fix this by removing the wrong check at btrfs_direct_IO().

Fixes: edf064e7 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When balance and scrub are running in parallel it is possible to end up
with an underflow of the bytes_may_use counter of the data space_info
object, which triggers a warning like the following:

   [134243.793196] BTRFS info (device sdc): relocating block group 1104150528 flags data
   [134243.806891] ------------[ cut here ]------------
   [134243.807561] WARNING: CPU: 1 PID: 26884 at fs/btrfs/space-info.h:125 btrfs_add_reserved_bytes+0x1da/0x280 [btrfs]
   [134243.808819] Modules linked in: btrfs blake2b_generic xor (...)
   [134243.815779] CPU: 1 PID: 26884 Comm: kworker/u8:8 Tainted: G        W         5.6.0-rc7-btrfs-next-58 #5
   [134243.816944] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
   [134243.818389] Workqueue: writeback wb_workfn (flush-btrfs-108483)
   [134243.819186] RIP: 0010:btrfs_add_reserved_bytes+0x1da/0x280 [btrfs]
   [134243.819963] Code: 0b f2 85 (...)
   [134243.822271] RSP: 0018:ffffa4160aae7510 EFLAGS: 00010287
   [134243.822929] RAX: 000000000000c000 RBX: ffff96159a8c1000 RCX: 0000000000000000
   [134243.823816] RDX: 0000000000008000 RSI: 0000000000000000 RDI: ffff96158067a810
   [134243.824742] RBP: ffff96158067a800 R08: 0000000000000001 R09: 0000000000000000
   [134243.825636] R10: ffff961501432a40 R11: 0000000000000000 R12: 000000000000c000
   [134243.826532] R13: 0000000000000001 R14: ffffffffffff4000 R15: ffff96158067a810
   [134243.827432] FS:  0000000000000000(0000) GS:ffff9615baa00000(0000) knlGS:0000000000000000
   [134243.828451] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [134243.829184] CR2: 000055bd7e414000 CR3: 00000001077be004 CR4: 00000000003606e0
   [134243.830083] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [134243.830975] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [134243.831867] Call Trace:
   [134243.832211]  find_free_extent+0x4a0/0x16c0 [btrfs]
   [134243.832846]  btrfs_reserve_extent+0x91/0x180 [btrfs]
   [134243.833487]  cow_file_range+0x12d/0x490 [btrfs]
   [134243.834080]  fallback_to_cow+0x82/0x1b0 [btrfs]
   [134243.834689]  ? release_extent_buffer+0x121/0x170 [btrfs]
   [134243.835370]  run_delalloc_nocow+0x33f/0xa30 [btrfs]
   [134243.836032]  btrfs_run_delalloc_range+0x1ea/0x6d0 [btrfs]
   [134243.836725]  ? find_lock_delalloc_range+0x221/0x250 [btrfs]
   [134243.837450]  writepage_delalloc+0xe8/0x150 [btrfs]
   [134243.838059]  __extent_writepage+0xe8/0x4c0 [btrfs]
   [134243.838674]  extent_write_cache_pages+0x237/0x530 [btrfs]
   [134243.839364]  extent_writepages+0x44/0xa0 [btrfs]
   [134243.839946]  do_writepages+0x23/0x80
   [134243.840401]  __writeback_single_inode+0x59/0x700
   [134243.841006]  writeback_sb_inodes+0x267/0x5f0
   [134243.841548]  __writeback_inodes_wb+0x87/0xe0
   [134243.842091]  wb_writeback+0x382/0x590
   [134243.842574]  ? wb_workfn+0x4a2/0x6c0
   [134243.843030]  wb_workfn+0x4a2/0x6c0
   [134243.843468]  process_one_work+0x26d/0x6a0
   [134243.843978]  worker_thread+0x4f/0x3e0
   [134243.844452]  ? process_one_work+0x6a0/0x6a0
   [134243.844981]  kthread+0x103/0x140
   [134243.845400]  ? kthread_create_worker_on_cpu+0x70/0x70
   [134243.846030]  ret_from_fork+0x3a/0x50
   [134243.846494] irq event stamp: 0
   [134243.846892] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
   [134243.847682] hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
   [134243.848687] softirqs last  enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
   [134243.849913] softirqs last disabled at (0): [<0000000000000000>] 0x0
   [134243.850698] ---[ end trace bd7c03622e0b0a96 ]---
   [134243.851335] ------------[ cut here ]------------

When relocating a data block group, for each extent allocated in the
block group we preallocate another extent with the same size for the
data relocation inode (we do it at prealloc_file_extent_cluster()).
We reserve space by calling btrfs_check_data_free_space(), which ends
up incrementing the data space_info's bytes_may_use counter, and
then call btrfs_prealloc_file_range() to allocate the extent, which
always decrements the bytes_may_use counter by the same amount.

The expectation is that writeback of the data relocation inode always
follows a NOCOW path, by writing into the preallocated extents. However,
when starting writeback we might end up falling back into the COW path,
because the block group that contains the preallocated extent was turned
into RO mode by a scrub running in parallel. The COW path then calls the
extent allocator which ends up calling btrfs_add_reserved_bytes(), and
this function decrements the bytes_may_use counter of the data space_info
object by an amount corresponding to the size of the allocated extent,
despite we haven't previously incremented it. When the counter currently
has a value smaller then the allocated extent we reset the counter to 0
and emit a warning, otherwise we just decrement it and slowly mess up
with this counter which is crucial for space reservation, the end result
can be granting reserved space to tasks when there isn't really enough
free space, and having the tasks fail later in critical places where
error handling consists of a transaction abort or hitting a BUG_ON().

Fix this by making sure that if we fallback to the COW path for a data
relocation inode, we increment the bytes_may_use counter of the data
space_info object. The COW path will then decrement it at
btrfs_add_reserved_bytes() on success or through its error handling part
by a call to extent_clear_unlock_delalloc() (which ends up calling
btrfs_clear_delalloc_extent() that does the decrement operation) in case
of an error.

Test case btrfs/061 from fstests could sporadically trigger this.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When running relocation of a data block group while scrub is running in
parallel, it is possible that the relocation will fail and abort the
current transaction with an -EINVAL error:

   [134243.988595] BTRFS info (device sdc): found 14 extents, stage: move data extents
   [134243.999871] ------------[ cut here ]------------
   [134244.000741] BTRFS: Transaction aborted (error -22)
   [134244.001692] WARNING: CPU: 0 PID: 26954 at fs/btrfs/ctree.c:1071 __btrfs_cow_block+0x6a7/0x790 [btrfs]
   [134244.003380] Modules linked in: btrfs blake2b_generic xor raid6_pq (...)
   [134244.012577] CPU: 0 PID: 26954 Comm: btrfs Tainted: G        W         5.6.0-rc7-btrfs-next-58 #5
   [134244.014162] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
   [134244.016184] RIP: 0010:__btrfs_cow_block+0x6a7/0x790 [btrfs]
   [134244.017151] Code: 48 c7 c7 (...)
   [134244.020549] RSP: 0018:ffffa41607863888 EFLAGS: 00010286
   [134244.021515] RAX: 0000000000000000 RBX: ffff9614bdfe09c8 RCX: 0000000000000000
   [134244.022822] RDX: 0000000000000001 RSI: ffffffffb3d63980 RDI: 0000000000000001
   [134244.024124] RBP: ffff961589e8c000 R08: 0000000000000000 R09: 0000000000000001
   [134244.025424] R10: ffffffffc0ae5955 R11: 0000000000000000 R12: ffff9614bd530d08
   [134244.026725] R13: ffff9614ced41b88 R14: ffff9614bdfe2a48 R15: 0000000000000000
   [134244.028024] FS:  00007f29b63c08c0(0000) GS:ffff9615ba600000(0000) knlGS:0000000000000000
   [134244.029491] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [134244.030560] CR2: 00007f4eb339b000 CR3: 0000000130d6e006 CR4: 00000000003606f0
   [134244.031997] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [134244.033153] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [134244.034484] Call Trace:
   [134244.034984]  btrfs_cow_block+0x12b/0x2b0 [btrfs]
   [134244.035859]  do_relocation+0x30b/0x790 [btrfs]
   [134244.036681]  ? do_raw_spin_unlock+0x49/0xc0
   [134244.037460]  ? _raw_spin_unlock+0x29/0x40
   [134244.038235]  relocate_tree_blocks+0x37b/0x730 [btrfs]
   [134244.039245]  relocate_block_group+0x388/0x770 [btrfs]
   [134244.040228]  btrfs_relocate_block_group+0x161/0x2e0 [btrfs]
   [134244.041323]  btrfs_relocate_chunk+0x36/0x110 [btrfs]
   [134244.041345]  btrfs_balance+0xc06/0x1860 [btrfs]
   [134244.043382]  ? btrfs_ioctl_balance+0x27c/0x310 [btrfs]
   [134244.045586]  btrfs_ioctl_balance+0x1ed/0x310 [btrfs]
   [134244.045611]  btrfs_ioctl+0x1880/0x3760 [btrfs]
   [134244.049043]  ? do_raw_spin_unlock+0x49/0xc0
   [134244.049838]  ? _raw_spin_unlock+0x29/0x40
   [134244.050587]  ? __handle_mm_fault+0x11b3/0x14b0
   [134244.051417]  ? ksys_ioctl+0x92/0xb0
   [134244.052070]  ksys_ioctl+0x92/0xb0
   [134244.052701]  ? trace_hardirqs_off_thunk+0x1a/0x1c
   [134244.053511]  __x64_sys_ioctl+0x16/0x20
   [134244.054206]  do_syscall_64+0x5c/0x280
   [134244.054891]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
   [134244.055819] RIP: 0033:0x7f29b51c9dd7
   [134244.056491] Code: 00 00 00 (...)
   [134244.059767] RSP: 002b:00007ffcccc1dd08 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
   [134244.061168] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f29b51c9dd7
   [134244.062474] RDX: 00007ffcccc1dda0 RSI: 00000000c4009420 RDI: 0000000000000003
   [134244.063771] RBP: 0000000000000003 R08: 00005565cea4b000 R09: 0000000000000000
   [134244.065032] R10: 0000000000000541 R11: 0000000000000202 R12: 00007ffcccc2060a
   [134244.066327] R13: 00007ffcccc1dda0 R14: 0000000000000002 R15: 00007ffcccc1dec0
   [134244.067626] irq event stamp: 0
   [134244.068202] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
   [134244.069351] hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
   [134244.070909] softirqs last  enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
   [134244.072392] softirqs last disabled at (0): [<0000000000000000>] 0x0
   [134244.073432] ---[ end trace bd7c03622e0b0a99 ]---

The -EINVAL error comes from the following chain of function calls:

  __btrfs_cow_block() <-- aborts the transaction
    btrfs_reloc_cow_block()
      replace_file_extents()
        get_new_location() <-- returns -EINVAL

When relocating a data block group, for each allocated extent of the block
group, we preallocate another extent (at prealloc_file_extent_cluster()),
associated with the data relocation inode, and then dirty all its pages.
These preallocated extents have, and must have, the same size that extents
from the data block group being relocated have.

Later before we start the relocation stage that updates pointers (bytenr
field of file extent items) to point to the the new extents, we trigger
writeback for the data relocation inode. The expectation is that writeback
will write the pages to the previously preallocated extents, that it
follows the NOCOW path. That is generally the case, however, if a scrub
is running it may have turned the block group that contains those extents
into RO mode, in which case writeback falls back to the COW path.

However in the COW path instead of allocating exactly one extent with the
expected size, the allocator may end up allocating several smaller extents
due to free space fragmentation - because we tell it at cow_file_range()
that the minimum allocation size can match the filesystem's sector size.
This later breaks the relocation's expectation that an extent associated
to a file extent item in the data relocation inode has the same size as
the respective extent pointed by a file extent item in another tree - in
this case the extent to which the relocation inode poins to is smaller,
causing relocation.c:get_new_location() to return -EINVAL.

For example, if we are relocating a data block group X that has a logical
address of X and the block group has an extent allocated at the logical
address X + 128KiB with a size of 64KiB:

1) At prealloc_file_extent_cluster() we allocate an extent for the data
   relocation inode with a size of 64KiB and associate it to the file
   offset 128KiB (X + 128KiB - X) of the data relocation inode. This
   preallocated extent was allocated at block group Z;

2) A scrub running in parallel turns block group Z into RO mode and
   starts scrubing its extents;

3) Relocation triggers writeback for the data relocation inode;

4) When running delalloc (btrfs_run_delalloc_range()), we try first the
   NOCOW path because the data relocation inode has BTRFS_INODE_PREALLOC
   set in its flags. However, because block group Z is in RO mode, the
   NOCOW path (run_delalloc_nocow()) falls back into the COW path, by
   calling cow_file_range();

5) At cow_file_range(), in the first iteration of the while loop we call
   btrfs_reserve_extent() to allocate a 64KiB extent and pass it a minimum
   allocation size of 4KiB (fs_info->sectorsize). Due to free space
   fragmentation, btrfs_reserve_extent() ends up allocating two extents
   of 32KiB each, each one on a different iteration of that while loop;

6) Writeback of the data relocation inode completes;

7) Relocation proceeds and ends up at relocation.c:replace_file_extents(),
   with a leaf which has a file extent item that points to the data extent
   from block group X, that has a logical address (bytenr) of X + 128KiB
   and a size of 64KiB. Then it calls get_new_location(), which does a
   lookup in the data relocation tree for a file extent item starting at
   offset 128KiB (X + 128KiB - X) and belonging to the data relocation
   inode. It finds a corresponding file extent item, however that item
   points to an extent that has a size of 32KiB, which doesn't match the
   expected size of 64KiB, resuling in -EINVAL being returned from this
   function and propagated up to __btrfs_cow_block(), which aborts the
   current transaction.

To fix this make sure that at cow_file_range() when we call the allocator
we pass it a minimum allocation size corresponding the desired extent size
if the inode belongs to the data relocation tree, otherwise pass it the
filesystem's sector size as the minimum allocation size.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This reverts commit a43a67a2.

This patch reverts the main part of switching direct io implementation
to iomap infrastructure. There's a problem in invalidate page that
couldn't be solved as regression in this development cycle.

The problem occurs when buffered and direct io are mixed, and the ranges
overlap. Although this is not recommended, filesystems implement
measures or fallbacks to make it somehow work. In this case, fallback to
buffered IO would be an option for btrfs (this already happens when
direct io is done on compressed data), but the change would be needed in
the iomap code, bringing new semantics to other filesystems.

Another problem arises when again the buffered and direct ios are mixed,
invalidation fails, then -EIO is set on the mapping and fsync will fail,
though there's no real error.

There have been discussions how to fix that, but revert seems to be the
least intrusive option.

Link: https://lore.kernel.org/linux-btrfs/20200528192103.xm45qoxqmkw7i5yl@fiona/Signed-off-by: NDavid Sterba <dsterba@suse.com>

This reverts commit 5f008163.

The patch is a simplification after direct IO port to iomap
infrastructure, which gets reverted.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This reverts commit d8f3e735.

The patch is a cleanup of direct IO port to iomap infrastructure,
which gets reverted.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

By moving FIEMAP_FLAG_SYNC handling to fiemap_prep we ensure it is
handled once instead of duplicated, but can still be done under fs locks,
like xfs/iomap intended with its duplicate handling.  Also make sure the
error value of filemap_write_and_wait is propagated to user space.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-8-hch@lst.deSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Replace fiemap_check_flags with a fiemap_prep helper that also takes the
inode and mapped range, and performs the sanity check and truncation
previously done in fiemap_check_range.  This way the validation is inside
the file system itself and thus properly works for the stacked overlayfs
case as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-7-hch@lst.deSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Since the new pair function is introduced, we can call them to clean the
code in btrfs.
Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NDavid Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Link: http://lkml.kernel.org/r/20200517214718.468-4-guoqing.jiang@cloud.ionos.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement the new readahead method in btrfs using the new
readahead_page_batch() function.
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NWilliam Kucharski <william.kucharski@oracle.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-18-willy@infradead.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We always preallocate a data extent for writing a free space cache, which
causes writeback to always try the nocow path first, since the free space
inode has the prealloc bit set in its flags.

However if the block group that contains the data extent for the space
cache has been turned to RO mode due to a running scrub or balance for
example, we have to fallback to the cow path. In that case once a new data
extent is allocated we end up calling btrfs_add_reserved_bytes(), which
decrements the counter named bytes_may_use from the data space_info object
with the expection that this counter was previously incremented with the
same amount (the size of the data extent).

However when we started writeout of the space cache at cache_save_setup(),
we incremented the value of the bytes_may_use counter through a call to
btrfs_check_data_free_space() and then decremented it through a call to
btrfs_prealloc_file_range_trans() immediately after. So when starting the
writeback if we fallback to cow mode we have to increment the counter
bytes_may_use of the data space_info again to compensate for the extent
allocation done by the cow path.

When this issue happens we are incorrectly decrementing the bytes_may_use
counter and when its current value is smaller then the amount we try to
subtract we end up with the following warning:

 ------------[ cut here ]------------
 WARNING: CPU: 3 PID: 657 at fs/btrfs/space-info.h:115 btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
 Modules linked in: btrfs blake2b_generic xor raid6_pq libcrc32c (...)
 CPU: 3 PID: 657 Comm: kworker/u8:7 Tainted: G        W         5.6.0-rc7-btrfs-next-58 #5
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
 Workqueue: writeback wb_workfn (flush-btrfs-1591)
 RIP: 0010:btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
 Code: ff ff 48 (...)
 RSP: 0000:ffffa41608f13660 EFLAGS: 00010287
 RAX: 0000000000001000 RBX: ffff9615b93ae400 RCX: 0000000000000000
 RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffff9615b96ab410
 RBP: fffffffffffee000 R08: 0000000000000001 R09: 0000000000000000
 R10: ffff961585e62a40 R11: 0000000000000000 R12: ffff9615b96ab400
 R13: ffff9615a1a2a000 R14: 0000000000012000 R15: ffff9615b93ae400
 FS:  0000000000000000(0000) GS:ffff9615bb200000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 000055cbbc2ae178 CR3: 0000000115794006 CR4: 00000000003606e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  find_free_extent+0x4a0/0x16c0 [btrfs]
  btrfs_reserve_extent+0x91/0x180 [btrfs]
  cow_file_range+0x12d/0x490 [btrfs]
  btrfs_run_delalloc_range+0x9f/0x6d0 [btrfs]
  ? find_lock_delalloc_range+0x221/0x250 [btrfs]
  writepage_delalloc+0xe8/0x150 [btrfs]
  __extent_writepage+0xe8/0x4c0 [btrfs]
  extent_write_cache_pages+0x237/0x530 [btrfs]
  extent_writepages+0x44/0xa0 [btrfs]
  do_writepages+0x23/0x80
  __writeback_single_inode+0x59/0x700
  writeback_sb_inodes+0x267/0x5f0
  __writeback_inodes_wb+0x87/0xe0
  wb_writeback+0x382/0x590
  ? wb_workfn+0x4a2/0x6c0
  wb_workfn+0x4a2/0x6c0
  process_one_work+0x26d/0x6a0
  worker_thread+0x4f/0x3e0
  ? process_one_work+0x6a0/0x6a0
  kthread+0x103/0x140
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x3a/0x50
 irq event stamp: 0
 hardirqs last  enabled at (0): [<0000000000000000>] 0x0
 hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
 softirqs last  enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
 softirqs last disabled at (0): [<0000000000000000>] 0x0
 ---[ end trace bd7c03622e0b0a52 ]---
 ------------[ cut here ]------------

So fix this by incrementing the bytes_may_use counter of the data
space_info when we fallback to the cow path. If the cow path is successful
the counter is decremented after extent allocation (by
btrfs_add_reserved_bytes()), if it fails it ends up being decremented as
well when clearing the delalloc range (extent_clear_unlock_delalloc()).

This could be triggered sporadically by the test case btrfs/061 from
fstests.

Fixes: 82d5902d ("Btrfs: Support reading/writing on disk free ino cache")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When doing a buffered write we always try to reserve data space for it,
even when the file has the NOCOW bit set or the write falls into a file
range covered by a prealloc extent. This is done both because it is
expensive to check if we can do a nocow write (checking if an extent is
shared through reflinks or if there's a hole in the range for example),
and because when writeback starts we might actually need to fallback to
COW mode (for example the block group containing the target extents was
turned into RO mode due to a scrub or balance).

When we are unable to reserve data space we check if we can do a nocow
write, and if we can, we proceed with dirtying the pages and setting up
the range for delalloc. In this case the bytes_may_use counter of the
data space_info object is not incremented, unlike in the case where we
are able to reserve data space (done through btrfs_check_data_free_space()
which calls btrfs_alloc_data_chunk_ondemand()).

Later when running delalloc we attempt to start writeback in nocow mode
but we might revert back to cow mode, for example because in the meanwhile
a block group was turned into RO mode by a scrub or relocation. The cow
path after successfully allocating an extent ends up calling
btrfs_add_reserved_bytes(), which expects the bytes_may_use counter of
the data space_info object to have been incremented before - but we did
not do it when the buffered write started, since there was not enough
available data space. So btrfs_add_reserved_bytes() ends up decrementing
the bytes_may_use counter anyway, and when the counter's current value
is smaller then the size of the allocated extent we get a stack trace
like the following:

 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 20138 at fs/btrfs/space-info.h:115 btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
 Modules linked in: btrfs blake2b_generic xor raid6_pq libcrc32c (...)
 CPU: 0 PID: 20138 Comm: kworker/u8:15 Not tainted 5.6.0-rc7-btrfs-next-58 #5
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
 Workqueue: writeback wb_workfn (flush-btrfs-1754)
 RIP: 0010:btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
 Code: ff ff 48 (...)
 RSP: 0018:ffffbda18a4b3568 EFLAGS: 00010287
 RAX: 0000000000000000 RBX: ffff9ca076f5d800 RCX: 0000000000000000
 RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffff9ca068470410
 RBP: fffffffffffff000 R08: 0000000000000001 R09: 0000000000000000
 R10: ffff9ca079d58040 R11: 0000000000000000 R12: ffff9ca068470400
 R13: ffff9ca0408b2000 R14: 0000000000001000 R15: ffff9ca076f5d800
 FS:  0000000000000000(0000) GS:ffff9ca07a600000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00005605dbfe7048 CR3: 0000000138570006 CR4: 00000000003606f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  find_free_extent+0x4a0/0x16c0 [btrfs]
  btrfs_reserve_extent+0x91/0x180 [btrfs]
  cow_file_range+0x12d/0x490 [btrfs]
  run_delalloc_nocow+0x341/0xa40 [btrfs]
  btrfs_run_delalloc_range+0x1ea/0x6d0 [btrfs]
  ? find_lock_delalloc_range+0x221/0x250 [btrfs]
  writepage_delalloc+0xe8/0x150 [btrfs]
  __extent_writepage+0xe8/0x4c0 [btrfs]
  extent_write_cache_pages+0x237/0x530 [btrfs]
  ? btrfs_wq_submit_bio+0x9f/0xc0 [btrfs]
  extent_writepages+0x44/0xa0 [btrfs]
  do_writepages+0x23/0x80
  __writeback_single_inode+0x59/0x700
  writeback_sb_inodes+0x267/0x5f0
  __writeback_inodes_wb+0x87/0xe0
  wb_writeback+0x382/0x590
  ? wb_workfn+0x4a2/0x6c0
  wb_workfn+0x4a2/0x6c0
  process_one_work+0x26d/0x6a0
  worker_thread+0x4f/0x3e0
  ? process_one_work+0x6a0/0x6a0
  kthread+0x103/0x140
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x3a/0x50
 irq event stamp: 0
 hardirqs last  enabled at (0): [<0000000000000000>] 0x0
 hardirqs last disabled at (0): [<ffffffff94ebdedf>] copy_process+0x74f/0x2020
 softirqs last  enabled at (0): [<ffffffff94ebdedf>] copy_process+0x74f/0x2020
 softirqs last disabled at (0): [<0000000000000000>] 0x0
 ---[ end trace f9f6ef8ec4cd8ec9 ]---

So to fix this, when falling back into cow mode check if space was not
reserved, by testing for the bit EXTENT_NORESERVE in the respective file
range, and if not, increment the bytes_may_use counter for the data
space_info object. Also clear the EXTENT_NORESERVE bit from the range, so
that if the cow path fails it decrements the bytes_may_use counter when
clearing the delalloc range (through the btrfs_clear_delalloc_extent()
callback).

Fixes: 7ee9e440 ("Btrfs: check if we can nocow if we don't have data space")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

If an error happens while running dellaloc in COW mode for a range, we can
end up calling extent_clear_unlock_delalloc() for a range that goes beyond
our range's end offset by 1 byte, which affects 1 extra page. This results
in clearing bits and doing page operations (such as a page unlock) outside
our target range.

Fix that by calling extent_clear_unlock_delalloc() with an inclusive end
offset, instead of an exclusive end offset, at cow_file_range().

Fixes: a315e68f ("Btrfs: fix invalid attempt to free reserved space on failure to cow range")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The read and write versions don't have anything in common except for the
call to iomap_dio_rw.  So split this function, and merge each half into
its only caller.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Since we now perform direct reads using i_rwsem, we can remove this
inode flag used to co-ordinate unlocked reads.

The truncate call takes i_rwsem. This means it is correctly synchronized
with concurrent direct reads.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJohannes Thumshirn <jth@kernel.org>
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Switch from __blockdev_direct_IO() to iomap_dio_rw().
Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
as iomap_begin() for iomap direct I/O functions. This function
allocates and locks all the blocks required for the I/O.
btrfs_submit_direct() is used as the submit_io() hook for direct I/O
ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore so set it to noop.
Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

BTRFS direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.

Use iomap->iomap_end() to check for failed or incomplete direct I/O:
 - for writes, call __endio_write_update_ordered()
 - for reads, unlock extents

btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.

This patch removes last use of struct buffer_head from btrfs.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The inode lookup starting at btrfs_iget takes the full location key,
while only the objectid is used to match the inode, because the lookup
happens inside the given root thus the inode number is unique.
The entire location key is properly set up in btrfs_init_locked_inode.

Simplify the helpers and pass only inode number, renaming it to 'ino'
instead of 'objectid'. This allows to remove temporary variables key,
saving some stack space.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The main function to lookup a root by its id btrfs_get_fs_root takes the
whole key, while only using the objectid. The value of offset is preset
to (u64)-1 but not actually used until btrfs_find_root that does the
actual search.

Switch btrfs_get_fs_root to use only objectid and remove all local
variables that existed just for the lookup. The actual key for search is
set up in btrfs_get_fs_root, reusing another key variable.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are a lot of root owner checks in btrfs_truncate_inode_items()
like:

	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
	    root == fs_info->tree_root)

But considering that, only these trees can have INODE_ITEMs:

- tree root (for v1 space cache)
- subvolume trees
- tree reloc trees
- data reloc tree
- log trees

And since subvolume/tree reloc/data reloc trees all have SHAREABLE bit,
and we're checking tree root manually, so above check is just excluding
log trees.

This patch will replace two of such checks to a simpler one:

	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)

This would merge btrfs_drop_extent_cache() and lock_extent_bits() call
into the same if branch.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The name BTRFS_ROOT_REF_COWS is not very clear about the meaning.

In fact, that bit can only be set to those trees:

- Subvolume roots
- Data reloc root
- Reloc roots for above roots

All other trees won't get this bit set.  So just by the result, it is
obvious that, roots with this bit set can have tree blocks shared with
other trees.  Either shared by snapshots, or by reloc roots (an special
snapshot created by relocation).

This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to
make it easier to understand, and update all comment mentioning
"reference counted" to follow the rename.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Now that all set/get helpers use the eb from the token, we don't need to
pass it to many btrfs_token_*/btrfs_set_token_* helpers, saving some
stack space.
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When mounting, we handle deleted subvolume and orphan items.  First,
find add orphan roots, then add them to fs_root radix tree.  Second, in
tree-root, process each orphan item, skip if it is dead root.

The original algorithm is based on the list of dead_roots, one by one to
visit and check whether the objectid is consistent, the time complexity
is O (n ^ 2).  When processing 50000 deleted subvols, it takes about
120s.

Because btrfs_find_orphan_roots has already ran before us, and added
deleted subvol to fs_roots radix tree.

The fs root will only be removed from the fs_roots radix tree after the
cleaner process is started, and the cleaner will only start execution
after the mount is complete.

btrfs_orphan_cleanup can be called during the whole filesystem mount
lifetime, but only "tree root" will be used in this section of code, and
only mount time will be brought into tree root.

So we can quickly check whether the orphan item is dead root through the
fs_roots radix tree.
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NRobbie Ko <robbieko@synology.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Use crypto_shash_digest() instead of crypto_shash_init() +
crypto_shash_update() + crypto_shash_final().  This is more efficient.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Currently, direct I/O has its own versions of bio_readpage_error() and
btrfs_check_repairable() (dio_read_error() and
btrfs_check_dio_repairable(), respectively). The main difference is that
the direct I/O version doesn't do read validation. The rework of direct
I/O repair makes it possible to do validation, so we can get rid of
btrfs_check_dio_repairable() and combine bio_readpage_error() and
dio_read_error() into a new helper, btrfs_submit_read_repair().
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This was originally added in commit 8b110e39 ("Btrfs: implement
repair function when direct read fails") to avoid a deadlock. In that
commit, the direct I/O read endio executes on the endio_workers
workqueue, submits a repair bio, and waits for it to complete. The
repair bio endio must execute on a different workqueue, otherwise it
could block on the endio_workers workqueue becoming available, which
won't happen because the original endio is blocked on the repair bio.

As of the previous commit, the original endio doesn't wait for the
repair bio, so this separate workqueue is unnecessary.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Direct I/O read repair was originally implemented in commit 8b110e39
("Btrfs: implement repair function when direct read fails"). This
implementation is unnecessarily complicated. There is major code
duplication between __btrfs_subio_endio_read() (checks checksums and
handles I/O errors for files with checksums),
__btrfs_correct_data_nocsum() (handles I/O errors for files without
checksums), btrfs_retry_endio() (checks checksums and handles I/O errors
for retries of files with checksums), and btrfs_retry_endio_nocsum()
(handles I/O errors for retries of files without checksum). If it sounds
like these should be one function, that's because they should.
Additionally, these functions are very hard to follow due to their
excessive use of goto.

This commit replaces the original implementation. After the previous
commit getting rid of orig_bio, we can reuse the same endio callback for
repair I/O and the original I/O, we just need to track the file offset
and original iterator in the repair bio. We can also unify the handling
of files with and without checksums and simplify the control flow. We
also no longer have to wait for each repair I/O to complete one by one.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In the worst case, there are _4_ layers of bios in the Btrfs direct I/O
path:

1. The bio created by the generic direct I/O code (dio_bio).
2. A clone of dio_bio we create in btrfs_submit_direct() to represent
   the entire direct I/O range (orig_bio).
3. A partial clone of orig_bio limited to the size of a RAID stripe that
   we create in btrfs_submit_direct_hook().
4. Clones of each of those split bios for each RAID stripe that we
   create in btrfs_map_bio().

As of the previous commit, the second layer (orig_bio) is no longer
needed for anything: we can split dio_bio instead, and complete dio_bio
directly when all of the cloned bios complete. This lets us clean up a
bunch of cruft, including dip->subio_endio and dip->errors (we can use
dio_bio->bi_status instead). It also enables the next big cleanup of
direct I/O read repair.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The next commit will get rid of btrfs_dio_private->orig_bio. The only
thing we really need it for is containing all of the checksums, but we
can easily put the checksum array in btrfs_dio_private and have the
submitted bios reference the array. We can also look the checksums up
while we're setting up instead of the current awkward logic that looks
them up for orig_bio when the first split bio is submitted.

(Interestingly, btrfs_dio_private did contain the
checksums before commit 23ea8e5a ("Btrfs: load checksum data once
when submitting a direct read io"), but it didn't look them up up
front.)
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is really a reference count now, so convert it to refcount_t and
rename it to refs.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We haven't used this since commit 9be3395b ("Btrfs: use a btrfs
bioset instead of abusing bio internals").
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

__readpage_endio_check() is also used from the direct I/O read code, so
give it a more descriptive name.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>