On Thu, Feb 16, 2017 at 12:24:04PM -0800, Christoph Hellwig wrote: > 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? > Sure.. Brian > 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 -- 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
