ntfs: do not turn an unmappable runlist fragment into delalloc on write

ntfs_write_simple_iomap_begin_non_resident() has the same unchecked
retry.  LCN_RL_NOT_MAPPED passes its "lcn <= LCN_HOLE" test, so a
buffered write into a range whose extent record cannot be read is
merged into the runlist as LCN_DELALLOC over clusters that are already
allocated on disk, and write() succeeds.  If the record stays
unreadable, writeback fails too and the data never reaches the disk;
the error only shows up at a later fsync() or a synchronous write.

On the volume from the previous patch, after a read of the file, an
8 KiB pwrite() at vcn 1000 returns 8192, fsync() returns -EIO, and
after remount the range is unchanged.

Fail the lookup here too, with -ENOMEM or -EIO.  That pwrite() now
fails with -EIO.  Writes whose range can be mapped are unaffected.

Fixes: b041ca562526 ("ntfs: update iomap and address space operations")
Cc: stable@vger.kernel.org
Signed-off-by: Matthias Goergens <matthias.goergens@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions