2062 Commits

Author SHA1 Message Date
Josef Bacik
b9729ce014 btrfs: locking: rip out path->leave_spinning
We no longer distinguish between blocking and spinning, so rip out all
this code.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:54:02 +01:00
Josef Bacik
ac5887c8e0 btrfs: locking: remove all the blocking helpers
Now that we're using a rw_semaphore we no longer need to indicate if a
lock is blocking or not, nor do we need to flip the entire path from
blocking to spinning.  Remove these helpers and all the places they are
called.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:54:01 +01:00
David Sterba
223486c27b btrfs: switch cached fs_info::csum_size from u16 to u32
The fs_info value is 32bit, switch also the local u16 variables. This
leads to a better assembly code generated due to movzwl.

This simple change will shave some bytes on x86_64 and release config:

   text    data     bss     dec     hex filename
1090000   17980   14912 1122892  11224c pre/btrfs.ko
1089794   17980   14912 1122686  11217e post/btrfs.ko

DELTA: -206

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:59 +01:00
David Sterba
55fc29bed8 btrfs: use cached value of fs_info::csum_size everywhere
btrfs_get_16 shows up in the system performance profiles (helper to read
16bit values from on-disk structures). This is partially because of the
checksum size that's frequently read along with data reads/writes, other
u16 uses are from item size or directory entries.

Replace all calls to btrfs_super_csum_size by the cached value from
fs_info.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:59 +01:00
David Sterba
265fdfa6ce btrfs: replace s_blocksize_bits with fs_info::sectorsize_bits
The value of super_block::s_blocksize_bits is the same as
fs_info::sectorsize_bits, but we don't need to do the extra dereferences
in many functions and storing the bits as u32 (in fs_info) generates
shorter assembly.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:58 +01:00
Qu Wenruo
265d4ac03f btrfs: sink parameter start and len to check_data_csum
For check_data_csum(), the page we're using is directly from the inode
mapping, thus it has valid page_offset().

We can use (page_offset() + pg_off) to replace @start parameter
completely, while the @len should always be sectorsize.

Since we're here, also add some comment, as there are quite some
confusion in words like start/offset, without explaining whether it's
file_offset or logical bytenr.

This should not affect the existing behavior, as for current sectorsize
== PAGE_SIZE case, @pgoff should always be 0, and len is always
PAGE_SIZE (or sectorsize from the dio read path).

Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:55 +01:00
Qu Wenruo
8896a08d8e btrfs: replace fs_info and private_data with inode in btrfs_wq_submit_bio
All callers of btrfs_wq_submit_bio() pass struct inode as @private_data,
so there is no need for it to be (void *), replace it with "struct inode
*inode".

While we can extract fs_info from struct inode, also remove the @fs_info
parameter.

Since we're here, also replace all the (void *private_data) into (struct
inode *inode).

Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:54 +01:00
Qu Wenruo
3f6bb4aeb5 btrfs: sink the failed_start parameter to set_extent_bit
The @failed_start parameter is only paired with @exclusive_bits, and
those parameters are only used for EXTENT_LOCKED bit, which have their
own wrappers lock_extent_bits().

Thus for regular set_extent_bit() calls, the failed_start makes no
sense, just sink the parameter.

Also, since @failed_start and @exclusive_bits are used in pairs, add
an assert to make it obvious.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:54 +01:00
David Sterba
c842268458 btrfs: add set/get accessors for root_item::drop_level
The drop_level member is used directly unlike all the other int types in
root_item. Add the definition and use it everywhere. The type is u8 so
there's no conversion necessary and the helpers are properly inlined,
this is for consistency.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:52 +01:00
Goldwyn Rodrigues
ecfdc08b8c btrfs: remove dio iomap DSYNC workaround
This effectively reverts 09745ff88d93 ("btrfs: dio iomap DSYNC
workaround") now that the iomap API has been updated to allow
iomap_dio_complete() not to be called under i_rwsem anymore.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:49 +01:00
Goldwyn Rodrigues
502756b380 btrfs: remove btrfs_inode::dio_sem
The inode dio_sem can be eliminated because all DIO synchronization is
now performed through inode->i_rwsem that provides the same guarantees.

This reduces btrfs_inode size by 40 bytes.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:48 +01:00
Goldwyn Rodrigues
a14b78ad06 btrfs: introduce btrfs_inode_lock()/unlock()
btrfs_inode_lock/unlock() are wrappers around inode locks, separating
the type of lock and actual locking.

- 0 - default, exclusive lock
- BTRFS_ILOCK_SHARED - for shared locks, for possible parallel DIO
- BTRFS_ILOCK_TRY - for the RWF_NOWAIT sequence

The bits SHARED and TRY can be combined together.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:47 +01:00
Goldwyn Rodrigues
4e4cabece9 btrfs: split btrfs_direct_IO to read and write
The read and write DIO don't have anything in common except for the
call to iomap_dio_rw. Extract the write call into a new function to get
rid of conditional statements for direct write.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:45 +01:00
Josef Bacik
42437a6386 btrfs: introduce mount option rescue=ignorebadroots
In the face of extent root corruption, or any other core fs wide root
corruption we will fail to mount the file system.  This makes recovery
kind of a pain, because you need to fall back to userspace tools to
scrape off data.  Instead provide a mechanism to gracefully handle bad
roots, so we can at least mount read-only and possibly recover data from
the file system.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:41 +01:00
Josef Bacik
334c16d82c btrfs: push the NODATASUM check into btrfs_lookup_bio_sums
When we move to being able to handle NULL csum_roots it'll be cleaner to
just check in btrfs_lookup_bio_sums instead of at all of the caller
locations, so push the NODATASUM check into it as well so it's unified.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:39 +01:00
Filipe Manana
c334730988 btrfs: fix missing delalloc new bit for new delalloc ranges
When doing a buffered write, through one of the write family syscalls, we
look for ranges which currently don't have allocated extents and set the
'delalloc new' bit on them, so that we can report a correct number of used
blocks to the stat(2) syscall until delalloc is flushed and ordered extents
complete.

However there are a few other places where we can do a buffered write
against a range that is mapped to a hole (no extent allocated) and where
we do not set the 'new delalloc' bit. Those places are:

- Doing a memory mapped write against a hole;

- Cloning an inline extent into a hole starting at file offset 0;

- Calling btrfs_cont_expand() when the i_size of the file is not aligned
  to the sector size and is located in a hole. For example when cloning
  to a destination offset beyond EOF.

So after such cases, until the corresponding delalloc range is flushed and
the respective ordered extents complete, we can report an incorrect number
of blocks used through the stat(2) syscall.

In some cases we can end up reporting 0 used blocks to stat(2), which is a
particular bad value to report as it may mislead tools to think a file is
completely sparse when its i_size is not zero, making them skip reading
any data, an undesired consequence for tools such as archivers and other
backup tools, as reported a long time ago in the following thread (and
other past threads):

  https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html

Example reproducer:

  $ cat reproducer.sh
  #!/bin/bash

  MNT=/mnt/sdi
  DEV=/dev/sdi

  mkfs.btrfs -f $DEV > /dev/null
  # mkfs.xfs -f $DEV > /dev/null
  # mkfs.ext4 -F $DEV > /dev/null
  # mkfs.f2fs -f $DEV > /dev/null
  mount $DEV $MNT

  xfs_io -f -c "truncate 64K"   \
      -c "mmap -w 0 64K"        \
      -c "mwrite -S 0xab 0 64K" \
      -c "munmap"               \
      $MNT/foo

  blocks_used=$(stat -c %b $MNT/foo)
  echo "blocks used: $blocks_used"

  if [ $blocks_used -eq 0 ]; then
      echo "ERROR: blocks used is 0"
  fi

  umount $DEV

  $ ./reproducer.sh
  blocks used: 0
  ERROR: blocks used is 0

So move the logic that decides to set the 'delalloc bit' bit into the
function btrfs_set_extent_delalloc(), since that is what we use for all
those missing cases as well as for the cases that currently work well.

This change is also preparatory work for an upcoming patch that fixes
other problems related to tracking and reporting the number of bytes used
by an inode.

CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 22:15:59 +01:00
Filipe Manana
1afc708dca btrfs: fix relocation failure due to race with fallocate
When doing a fallocate() we have a short time window, after reserving an
extent and before starting a transaction, where if relocation for the block
group containing the reserved extent happens, we can end up missing the
extent in the data relocation inode causing relocation to fail later.

This only happens when we don't pass a transaction to the internal
fallocate function __btrfs_prealloc_file_range(), which is for all the
cases where fallocate() is called from user space (the internal use cases
include space cache extent allocation and relocation).

When the race triggers the relocation failure, it produces a trace like
the following:

  [200611.995995] ------------[ cut here ]------------
  [200611.997084] BTRFS: Transaction aborted (error -2)
  [200611.998208] WARNING: CPU: 3 PID: 235845 at fs/btrfs/ctree.c:1074 __btrfs_cow_block+0x3a0/0x5b0 [btrfs]
  [200611.999042] Modules linked in: dm_thin_pool dm_persistent_data (...)
  [200612.003287] CPU: 3 PID: 235845 Comm: btrfs Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [200612.004442] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  [200612.006186] RIP: 0010:__btrfs_cow_block+0x3a0/0x5b0 [btrfs]
  [200612.007110] Code: 1b 00 00 02 72 2a 83 f8 fb 0f 84 b8 01 (...)
  [200612.007341] BTRFS warning (device sdb): Skipping commit of aborted transaction.
  [200612.008959] RSP: 0018:ffffaee38550f918 EFLAGS: 00010286
  [200612.009672] BTRFS: error (device sdb) in cleanup_transaction:1901: errno=-30 Readonly filesystem
  [200612.010428] RAX: 0000000000000000 RBX: ffff9174d96f4000 RCX: 0000000000000000
  [200612.011078] BTRFS info (device sdb): forced readonly
  [200612.011862] RDX: 0000000000000001 RSI: ffffffffa8161978 RDI: 00000000ffffffff
  [200612.013215] RBP: ffff9172569a0f80 R08: 0000000000000000 R09: 0000000000000000
  [200612.014263] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9174b8403b88
  [200612.015203] R13: ffff9174b8400a88 R14: ffff9174c90f1000 R15: ffff9174a5a60e08
  [200612.016182] FS:  00007fa55cf878c0(0000) GS:ffff9174ece00000(0000) knlGS:0000000000000000
  [200612.017174] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [200612.018418] CR2: 00007f8fb8048148 CR3: 0000000428a46003 CR4: 00000000003706e0
  [200612.019510] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [200612.020648] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [200612.021520] Call Trace:
  [200612.022434]  btrfs_cow_block+0x10b/0x250 [btrfs]
  [200612.023407]  do_relocation+0x54e/0x7b0 [btrfs]
  [200612.024343]  ? do_raw_spin_unlock+0x4b/0xc0
  [200612.025280]  ? _raw_spin_unlock+0x29/0x40
  [200612.026200]  relocate_tree_blocks+0x3bc/0x6d0 [btrfs]
  [200612.027088]  relocate_block_group+0x2f3/0x600 [btrfs]
  [200612.027961]  btrfs_relocate_block_group+0x15e/0x340 [btrfs]
  [200612.028896]  btrfs_relocate_chunk+0x38/0x110 [btrfs]
  [200612.029772]  btrfs_balance+0xb22/0x1790 [btrfs]
  [200612.030601]  ? btrfs_ioctl_balance+0x253/0x380 [btrfs]
  [200612.031414]  btrfs_ioctl_balance+0x2cf/0x380 [btrfs]
  [200612.032279]  btrfs_ioctl+0x620/0x36f0 [btrfs]
  [200612.033077]  ? _raw_spin_unlock+0x29/0x40
  [200612.033948]  ? handle_mm_fault+0x116d/0x1ca0
  [200612.034749]  ? up_read+0x18/0x240
  [200612.035542]  ? __x64_sys_ioctl+0x83/0xb0
  [200612.036244]  __x64_sys_ioctl+0x83/0xb0
  [200612.037269]  do_syscall_64+0x33/0x80
  [200612.038190]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [200612.038976] RIP: 0033:0x7fa55d07ed87
  [200612.040127] Code: 00 00 00 48 8b 05 09 91 0c 00 64 c7 00 26 (...)
  [200612.041669] RSP: 002b:00007ffd5ebf03e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
  [200612.042437] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fa55d07ed87
  [200612.043511] RDX: 00007ffd5ebf0470 RSI: 00000000c4009420 RDI: 0000000000000003
  [200612.044250] RBP: 0000000000000003 R08: 000055d8362642a0 R09: 00007fa55d148be0
  [200612.044963] R10: fffffffffffff52e R11: 0000000000000206 R12: 00007ffd5ebf1614
  [200612.045683] R13: 00007ffd5ebf0470 R14: 0000000000000002 R15: 00007ffd5ebf0470
  [200612.046361] irq event stamp: 0
  [200612.047040] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  [200612.047725] hardirqs last disabled at (0): [<ffffffffa6eb5ab3>] copy_process+0x823/0x1bc0
  [200612.048387] softirqs last  enabled at (0): [<ffffffffa6eb5ab3>] copy_process+0x823/0x1bc0
  [200612.049024] softirqs last disabled at (0): [<0000000000000000>] 0x0
  [200612.049722] ---[ end trace 49006c6876e65227 ]---

The race happens like this:

1) Task A starts an fallocate() (plain or zero range) and it calls
   __btrfs_prealloc_file_range() with the 'trans' parameter set to NULL;

2) Task A calls btrfs_reserve_extent() and gets an extent that belongs to
   block group X;

3) Before task A gets into btrfs_replace_file_extents(), through the call
   to insert_prealloc_file_extent(), task B starts relocation of block
   group X;

4) Task B enters btrfs_relocate_block_group() and it sets block group X to
   RO mode;

5) Task B enters relocate_block_group(), it calls prepare_to_relocate()
   whichs joins/starts a transaction and then commits the transaction;

6) Task B then starts scanning the extent tree looking for extents that
   belong to block group X - it does not find yet the extent reserved by
   task A, since that extent was not yet added to the extent tree, as its
   delayed reference was not even yet created at this point;

7) The data relocation inode ends up not having the extent reserved by
   task A associated to it;

8) Task A then starts a transaction through btrfs_replace_file_extents(),
   inserts a file extent item in the subvolume tree pointing to the
   reserved extent and creates a delayed reference for it;

9) Task A finishes and returns success to user space;

10) Later on, while relocation is still in progress, the leaf where task A
    inserted the new file extent item is COWed, so we end up at
    __btrfs_cow_block(), which calls btrfs_reloc_cow_block(), and that in
    turn calls relocation.c:replace_file_extents();

11) At relocation.c:replace_file_extents() we iterate over all the items in
    the leaf and find the file extent item pointing to the extent that was
    allocated by task A, and then call relocation.c:get_new_location(), to
    find the new location for the extent;

12) However relocation.c:get_new_location() fails, returning -ENOENT,
    because it couldn't find a corresponding file extent item associated
    with the data relocation inode. This is because the extent was not seen
    in the extent tree at step 6). The -ENOENT error is propagated to
    __btrfs_cow_block(), which aborts the transaction.

So fix this simply by decrementing the block group's number of reservations
after calling insert_prealloc_file_extent(), as relocation waits for that
counter to go down to zero before calling prepare_to_relocate() and start
looking for extents in the extent tree.

This issue only started to happen recently as of commit 8fccebfa534c79
("btrfs: fix metadata reservation for fallocate that leads to transaction
aborts"), because now we can reserve an extent before starting/joining a
transaction, and previously we always did it after that, so relocation
ended up waiting for a concurrent fallocate() to finish because before
searching for the extents of the block group, it starts/joins a transaction
and then commits it (at prepare_to_relocate()), which made it wait for the
fallocate task to complete first.

Fixes: 8fccebfa534c79 ("btrfs: fix metadata reservation for fallocate that leads to transaction aborts")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-16 16:01:56 +02:00
Nikolay Borisov
1fd4033dd0 btrfs: rename BTRFS_INODE_ORDERED_DATA_CLOSE flag
Commit 8d875f95da43 ("btrfs: disable strict file flushes for
renames and truncates") eliminated the notion of ordered operations and
instead BTRFS_INODE_ORDERED_DATA_CLOSE only remained as a flag
indicating that a file's content should be synced to disk in case a
file is truncated and any writes happen to it concurrently. In fact
this intendend behavior was broken until it was fixed in
f6dc45c7a93a ("Btrfs: fix filemap_flush call in btrfs_file_release").

All things considered let's give the flag a more descriptive name. Also
slightly reword comments.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:18:00 +02:00
Goldwyn Rodrigues
e3c57805f8 btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK
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: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:17:59 +02:00
Nikolay Borisov
905eb88bce btrfs: remove struct extent_io_ops
It's no longer used just remove the function and any related code which
was initialising it for inodes. No functional changes.

Removing 8 bytes from extent_io_tree in turn reduces size of other
structures where it is embedded, notably btrfs_inode where it reduces
size by 24 bytes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:25 +02:00
Nikolay Borisov
908930f3ed btrfs: stop calling submit_bio_hook for data inodes
Instead export and rename the function to btrfs_submit_data_bio and
call it directly in submit_one_bio. This avoids paying the cost for
speculative attacks mitigations and improves code readability.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:24 +02:00
Nikolay Borisov
1f03d9cfda btrfs: remove extent_io_ops::readpage_end_io_hook
It's no longer used so let's remove it.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:24 +02:00
Nikolay Borisov
9a446d6a9f btrfs: replace readpage_end_io_hook with direct calls
Don't call readpage_end_io_hook for the btree inode.  Instead of relying
on indirect calls to implement metadata buffer validation simply check
if the inode whose page we are processing equals the btree inode. If it
does call the necessary function.

This is an improvement in 2 directions:

1. We aren't paying the penalty of indirect calls in a post-speculation
   attacks world.

2. The function is now named more explicitly so it's obvious what's
   going on

This is in preparation to removing struct extent_io_ops altogether.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:24 +02:00
Nikolay Borisov
c0a4360305 btrfs: remove inode argument from btrfs_start_ordered_extent
The passed in ordered_extent struct is always well-formed and contains
the inode making the explicit argument redundant.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:22 +02:00
Nikolay Borisov
510f85edf1 btrfs: remove inode argument from add_pending_csums
It's used to reference the csum root which can be done from the trans
handle as well. Simplify the signature and while at it also remove the
noinline attribute as the function uses only at most 16 bytes of stack
space.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:21 +02:00
Nikolay Borisov
3c38c877fc btrfs: sink inode argument in insert_ordered_extent_file_extent
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:21 +02:00
Nikolay Borisov
71fe0a55da btrfs: switch btrfs_remove_ordered_extent to btrfs_inode
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:21 +02:00
Nikolay Borisov
633cc816f7 btrfs: clean BTRFS_I usage in btrfs_destroy_inode
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:21 +02:00
Nikolay Borisov
0f20881249 btrfs: open code extent_read_full_page to its sole caller
This makes reading the code a tad easier by decreasing the level of
indirection by one.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:21 +02:00
Nikolay Borisov
6f15af6060 btrfs: sink read_flags argument into extent_read_full_page
It's always set to 0 by its sole caller - btrfs_readpage. Simply remove
it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:20 +02:00
Nikolay Borisov
003c286aef btrfs: sink mirror_num argument in extent_read_full_page
It's always set to 0 from the sole caller - btrfs_readpage.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:20 +02:00
Nikolay Borisov
c1be9c1ad5 btrfs: promote extent_read_full_page to btrfs_readpage
Now that btrfs_readpage is the only caller of extent_read_full_page the
latter can be open coded in the former. Use the occassion to rename
__extent_read_full_page to extent_read_full_page. To facillitate this
change submit_one_bio has to be exported as well.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:20 +02:00
Nikolay Borisov
72cffee463 btrfs: remove mirror_num argument from extent_read_full_page
It's called only from btrfs_readpage which always passes 0 so just sink
the argument into extent_read_full_page.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:20 +02:00
Nikolay Borisov
1a5ee1e626 btrfs: remove btrfs_get_extent indirection from __do_readpage
Now that this function is only responsible for reading data pages it's
no longer necessary to pass get_extent_t parameter across several
layers of functions. This patch removes this parameter from multiple
functions: __get_extent_map/__do_readpage/__extent_read_full_page/
extent_read_full_page and simply calls btrfs_get_extent directly in
__get_extent_map.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:20 +02:00
Filipe Manana
306bfec02b btrfs: rename btrfs_punch_hole_range() to a more generic name
The function btrfs_punch_hole_range() is now used to replace all the file
extents in a given file range with an extent described in the given struct
btrfs_replace_extent_info argument. This extent can either be an existing
extent that is being cloned or it can be a new extent (namely a prealloc
extent). When that argument is NULL it only punches a hole (drops all the
existing extents) in the file range.

So rename the function to btrfs_replace_file_extents().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:17 +02:00
Filipe Manana
bf385648fa btrfs: rename struct btrfs_clone_extent_info to a more generic name
Now that we can use btrfs_clone_extent_info to convey information for a
new prealloc extent as well, and not just for existing extents that are
being cloned, rename it to btrfs_replace_extent_info, which reflects the
fact that this is now more generic and it is used to replace all existing
extents in a file range with the extent described by the structure.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:16 +02:00
Filipe Manana
fb870f6cdd btrfs: remove item_size member of struct btrfs_clone_extent_info
The value of item_size of struct btrfs_clone_extent_info is always set to
the size of a non-inline file extent item, and in fact the infrastructure
that uses this structure (btrfs_punch_hole_range()) does not work with
inline file extents at all (and it is not supposed to).

So just remove that field from the structure and use directly
sizeof(struct btrfs_file_extent_item) instead. Also assert that the
file extent type is not inline at btrfs_insert_clone_extent().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:16 +02:00
Filipe Manana
8fccebfa53 btrfs: fix metadata reservation for fallocate that leads to transaction aborts
When doing an fallocate(), specially a zero range operation, we assume
that reserving 3 units of metadata space is enough, that at most we touch
one leaf in subvolume/fs tree for removing existing file extent items and
inserting a new file extent item. This assumption is generally true for
most common use cases. However when we end up needing to remove file extent
items from multiple leaves, we can end up failing with -ENOSPC and abort
the current transaction, turning the filesystem to RO mode. When this
happens a stack trace like the following is dumped in dmesg/syslog:

[ 1500.620934] ------------[ cut here ]------------
[ 1500.620938] BTRFS: Transaction aborted (error -28)
[ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...)
[ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G        W         5.9.0-rc3-btrfs-next-67 #1
[ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs]
[ 1500.621026] Code: 8b 40 50 f0 48 (...)
[ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286
[ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000
[ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff
[ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001
[ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000
[ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60
[ 1500.621039] FS:  00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000
[ 1500.621041] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0
[ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1500.621049] Call Trace:
[ 1500.621076]  btrfs_prealloc_file_range+0x10/0x20 [btrfs]
[ 1500.621087]  btrfs_fallocate+0xccd/0x1280 [btrfs]
[ 1500.621108]  vfs_fallocate+0x14d/0x290
[ 1500.621112]  ksys_fallocate+0x3a/0x70
[ 1500.621117]  __x64_sys_fallocate+0x1a/0x20
[ 1500.621120]  do_syscall_64+0x33/0x80
[ 1500.621123]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1500.621126] RIP: 0033:0x7fb5b248c477
[ 1500.621128] Code: 89 7c 24 08 (...)
[ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d
[ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477
[ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003
[ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000
[ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010
[ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003
[ 1500.621151] irq event stamp: 1026217
[ 1500.621154] hardirqs last  enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0
[ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0
[ 1500.621159] softirqs last  enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606
[ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20
[ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]---
[ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left

When we use fallocate() internally, for reserving an extent for a space
cache, inode cache or relocation, we can't hit this problem since either
there aren't any file extent items to remove from the subvolume tree or
there is at most one.

When using plain fallocate() it's very unlikely, since that would require
having many file extent items representing holes for the target range and
crossing multiple leafs - we attempt to increase the range (merge) of such
file extent items when punching holes, so at most we end up with 2 file
extent items for holes at leaf boundaries.

However when using the zero range operation of fallocate() for a large
range (100+ MiB for example) that's fairly easy to trigger. The following
example reproducer triggers the issue:

  $ cat reproducer.sh
  #!/bin/bash

  umount /dev/sdj &> /dev/null
  mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null
  mount /dev/sdj /mnt/sdj

  # Create a 100M file with many file extent items. Punch a hole every 8K
  # just to speedup the file creation - we could do 4K sequential writes
  # followed by fsync (or O_SYNC) as well, but that takes a lot of time.
  file_size=$((100 * 1024 * 1024))
  xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar
  for ((i = 0; i < $file_size; i += 8192)); do
      xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar
  done

  # Force a transaction commit, so the zero range operation will be forced
  # to COW all metadata extents it need to touch.
  sync

  xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar

  umount /mnt/sdj

  $ ./reproducer.sh
  wrote 104857600/104857600 bytes at offset 0
  100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec)
  fallocate: No space left on device

  $ dmesg
  <shows the same stack trace pasted before>

To fix this use the existing infrastructure that hole punching and
extent cloning use for replacing a file range with another extent. This
deals with doing the removal of file extent items and inserting the new
one using an incremental approach, reserving more space when needed and
always ensuring we don't leave an implicit hole in the range in case
we need to do multiple iterations and a crash happens between iterations.

A test case for fstests will follow up soon.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:13:16 +02:00
Goldwyn Rodrigues
c3e1f96c37 btrfs: enumerate the type of exclusive operation in progress
Instead of using a flag bit for exclusive operation, use a variable to
store which exclusive operation is being performed.  Introduce an API
to start and finish an exclusive operation.

This would enable another way for tools to check which operation is
running on why starting an exclusive operation failed. The followup
patch adds a sysfs_notify() to alert userspace when the state changes, so
userspace can perform select() on it to get notified of the change.

This would enable us to enqueue a command which will wait for current
exclusive operation to complete before issuing the next exclusive
operation. This has been done synchronously as opposed to a background
process, or else error collection (if any) will become difficult.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:20 +02:00
Nikolay Borisov
facee0a09c btrfs: make extent_fiemap take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:19 +02:00
Nikolay Borisov
3347c48f27 btrfs: make btrfs_writepage_endio_finish_ordered btrfs_inode-centric
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
53ac7ead24 btrfs: make btrfs_invalidatepage work on btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
90c0304c63 btrfs: make btrfs_dec_test_ordered_pending take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
6d072c8e29 btrfs: make btrfs_lookup_first_ordered_extent take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Nikolay Borisov
b79b724969 btrfs: make inode_tree_del take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Josef Bacik
51899412dd btrfs: introduce btrfs_path::recurse
Our current tree locking stuff allows us to recurse with read locks if
we're already holding the write lock.  This is necessary for the space
cache inode, as we could be holding a lock on the root_tree root when we
need to cache a block group, and thus need to be able to read down the
root_tree to read in the inode cache.

We can get away with this in our current locking, but we won't be able
to with a rwsem.  Handle this by purposefully annotating the places
where we require recursion, so that in the future we can maybe come up
with a way to avoid the recursion.  In the case of the free space inode,
this will be superseded by the free space tree.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Qu Wenruo
e85fde5162 btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations
[BUG]
When quota is enabled for TEST_DEV, generic/013 sometimes fails like this:

  generic/013 14s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//generic/013.dmesg)

And with the following metadata leak:

  BTRFS warning (device dm-3): qgroup 0/1370 has unreleased space, type 2 rsv 49152
  ------------[ cut here ]------------
  WARNING: CPU: 2 PID: 47912 at fs/btrfs/disk-io.c:4078 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 a6cfd45ba80e4e06 ]---
  BTRFS error (device dm-3): qgroup reserved space leaked
  BTRFS info (device dm-3): disk space caching is enabled
  BTRFS info (device dm-3): has skinny extents

[CAUSE]
The qgroup preallocated meta rsv operations of that offending root are:

  btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072
  btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072
  btrfs_subvolume_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=49152
  btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072
  btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072

It's pretty obvious that, we reserve qgroup meta rsv in
btrfs_subvolume_reserve_metadata(), but doesn't have corresponding
release/convert calls in btrfs_subvolume_release_metadata().

This leads to the leakage.

[FIX]
To fix this bug, we should follow what we're doing in
btrfs_delalloc_reserve_metadata(), where we reserve qgroup space, and
add it to block_rsv->qgroup_rsv_reserved.

And free the qgroup reserved metadata space when releasing the
block_rsv.

To do this, we need to change the btrfs_subvolume_release_metadata() to
accept btrfs_root, and record the qgroup_to_release number, and call
btrfs_qgroup_convert_reserved_meta() for it.

Fixes: 733e03a0b26a ("btrfs: qgroup: Split meta rsv type into meta_prealloc and meta_pertrans")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:13 +02:00
Nikolay Borisov
1028d1c48b btrfs: remove err variable from btrfs_get_extent
There's no practical reason too use 'err' as a variable to convey
errors. In fact it's value is either set explicitly in the beginning of
the function or it simply takes the value of 'ret'. Not conforming to
the usual pattern of having ret be the only variable used to convey
errors makes the code more error prone to bugs. In fact one such bug
was introduced by 6bf9e4bd6a27 ("btrfs: inode: Verify inode mode toi
avoid NULL pointer dereference") by assigning the error value to 'ret'
and not 'err'.

Let's fix that issue and make the function less tricky by leaving only
ret to convey error values.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Josef Bacik
0eb79294db btrfs: dio iomap DSYNC workaround
iomap dio will run generic_write_sync() for us if the iocb is DSYNC.
This is problematic for us because of 2 reasons:

1. we hold the inode_lock() during this operation, and we take it in
   generic_write_sync()
2. we hold a read lock on the dio_sem but take the write lock in fsync

Since we don't want to rip out this code right now, but reworking the
locking is a bit much to do at this point, work around this problem with
this masterpiece of a patch.

First, we clear DSYNC on the iocb so that the iomap stuff doesn't know
that it needs to handle the sync.  We save this fact in
current->journal_info, because we need to see do special things once
we're in iomap_begin, and we have no way to pass private information
into iomap_dio_rw().

Next we specify a separate iomap_dio_ops for sync, which implements an
->end_io() callback that gets called when the dio completes.  This is
important for AIO, because we really do need to run generic_write_sync()
if we complete asynchronously.  However if we're still in the submitting
context when we enter ->end_io() we clear the flag so that the submitter
knows they're the ones that needs to run generic_write_sync().

This is meant to be temporary.  We need to work out how to eliminate the
inode_lock() and the dio_sem in our fsync and use another mechanism to
protect these operations.

Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Goldwyn Rodrigues
f85781fb50 btrfs: switch to iomap for direct IO
We're using direct io implementation based on buffer heads. This patch
switches to the new iomap infrastructure.

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: 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.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00