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author | Filipe Manana <fdmanana@suse.com> | 2020-06-15 20:48:58 +0300 |
---|---|---|
committer | Sasha Levin <sashal@kernel.org> | 2020-06-30 22:38:07 +0300 |
commit | bdbae19beef8db3687c81dfda63f79359a063c56 (patch) | |
tree | 877fd855c5b2d7cb0e38213441fa7c2ed8a956b6 /fs/btrfs | |
parent | 4e387bedce68c204f10cd023a2ef21435ec9b22e (diff) | |
download | linux-bdbae19beef8db3687c81dfda63f79359a063c56.tar.xz |
btrfs: fix failure of RWF_NOWAIT write into prealloc extent beyond eof
commit 4b1946284dd6641afdb9457101056d9e6ee6204c upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/btrfs')
-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 ad138f0b0ce1..39ad582d72c4 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8947,9 +8947,6 @@ 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); |