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| author | Filipe Manana <fdmanana@suse.com> | 2020-06-15 18:48:58 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-06-16 19:22:31 +0200 |
| commit | 4b1946284dd6641afdb9457101056d9e6ee6204c (patch) | |
| tree | e59a20e61c96f21ff798dd418f4deb97f72586ad /fs | |
| parent | f2cb2f39ccc30fa13d3ac078d461031a63960e5b (diff) | |
| download | linux-4b1946284dd6641afdb9457101056d9e6ee6204c.tar.bz2 | |
btrfs: fix failure of RWF_NOWAIT write into prealloc extent beyond eof
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: edf064e7c6fec3 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/inode.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 62b49d2db928..cfa863d2d97c 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7889,9 +7889,6 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) dio_data.overwrite = 1; inode_unlock(inode); relock = true; - } else if (iocb->ki_flags & IOCB_NOWAIT) { - ret = -EAGAIN; - goto out; } ret = btrfs_delalloc_reserve_space(inode, &data_reserved, offset, count); |