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btrfs: zoned: wait for data BG to be finished on direct IO allocation 

commit 776a838f1f upstream.

Running the fio command below on a ZNS device results in "Resource
temporarily unavailable" error.

  $ sudo fio --name=w --directory=/mnt --filesize=1GB --bs=16MB --numjobs=16 \
        --rw=write --ioengine=libaio --iodepth=128 --direct=1

  fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=117440512, buflen=16777216
  fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=134217728, buflen=16777216
  ...

This happens because -EAGAIN error returned from btrfs_reserve_extent()
called from btrfs_new_extent_direct() is spilling over to the userland.

btrfs_reserve_extent() returns -EAGAIN when there is no active zone
available. Then, the caller should wait for some other on-going IO to
finish a zone and retry the allocation.

This logic is already implemented for buffered write in cow_file_range(),
but it is missing for the direct IO counterpart. Implement the same logic
for it.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 2ce543f478 ("btrfs: zoned: wait until zone is finished when allocation didn't progress")
CC: stable@vger.kernel.org # 6.1+
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Naohiro Aota 2023-10-17 17:00:31 +09:00 committed by Greg Kroah-Hartman
parent 9ad4c7f065
commit a0d43e0f7c
1 changed files with 7 additions and 0 deletions
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7
fs/btrfs/inode.c
View File

@ -7166,8 +7166,15 @@ static struct extent_map *btrfs_new_extent_direct(struct btrfs_inode *inode,
int ret;
alloc_hint = get_extent_allocation_hint(inode, start, len);
again:
ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
0, alloc_hint, &ins, 1, 1);
if (ret == -EAGAIN) {
ASSERT(btrfs_is_zoned(fs_info));
wait_on_bit_io(&inode->root->fs_info->flags, BTRFS_FS_NEED_ZONE_FINISH,
TASK_UNINTERRUPTIBLE);
goto again;
}
if (ret)
return ERR_PTR(ret);