On Tue, Feb 14, 2017 at 08:03:06AM -0500, Brian Foster wrote: > The buffered write failure handling code in > xfs_file_iomap_end_delalloc() has a couple minor problems. First, if > written == 0, start_fsb is not rounded down and it fails to kill off a > delalloc block if the start offset is block unaligned. This results in a > lingering delalloc block and broken delalloc block accounting detected > at unmount time. Fix this by rounding down start_fsb in the unlikely > event that written == 0. > > Second, it is possible for a failed overwrite of a delalloc extent to > leave dirty pagecache around over a hole in the file. This is because is > possible to hit ->iomap_end() on write failure before the iomap code has > attempted to allocate pagecache, and thus has no need to clean it up. If > the targeted delalloc extent was successfully written by a previous > write, however, then it does still have dirty pages when ->iomap_end() > punches out the underlying blocks. This ultimately results in writeback > over a hole. To fix this problem, unconditionally punch out the > pagecache from XFS before the associated delalloc range. > > Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx> > --- > fs/xfs/xfs_iomap.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index e0bc290..e2fbed4 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -1079,6 +1079,8 @@ xfs_file_iomap_end_delalloc( > int error = 0; > > start_fsb = XFS_B_TO_FSB(mp, offset + written); > + if (unlikely(!written)) > + start_fsb = XFS_B_TO_FSBT(mp, offset); nitpick: use if/else here and maybe add a comment? Otherwise looks fine: Reviewed-by: Christoph Hellwig <hch@xxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
