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authorFilipe Manana <fdmanana@suse.com>2020-06-15 18:48:58 +0100
committerDavid Sterba <dsterba@suse.com>2020-06-16 19:22:31 +0200
commit4b1946284dd6641afdb9457101056d9e6ee6204c (patch)
treee59a20e61c96f21ff798dd418f4deb97f72586ad /fs
parentf2cb2f39ccc30fa13d3ac078d461031a63960e5b (diff)
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.c3
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);