On Sat, Aug 09, 2014 at 08:57:00AM -0400, Chris Mason wrote: > > xfs is using truncate_pagecache_range to invalidate the page cache > during DIO reads. This is different from the other filesystems who only > invalidate pages during DIO writes. > > truncate_pagecache_range is meant to be used when we are freeing the > underlying data structs from disk, so it will zero any partial ranges in > the page. This means a DIO read can zero out part of the page cache > page, and it is possible the page will stay in cache. > > buffered reads will find an up to date page with zeros instead of the > data actually on disk. > > This patch fixes things by using invalidate_inode_pages2_range instead. > It preserves the page cache invalidation, but won't zero any pages. > > Signed-off-by: Chris Mason <clm@xxxxxx> > cc: stable@xxxxxxxxxxxxxxx > > --- I can't say I grok the risk of removing the invalidation entirely, but this is certainly a more isolated fix: Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> > fs/xfs/xfs_file.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 1f66779..023d575 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -295,7 +295,8 @@ xfs_file_read_iter( > xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL); > return ret; > } > - truncate_pagecache_range(VFS_I(ip), pos, -1); > + invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, > + pos >> PAGE_CACHE_SHIFT, -1); > } > xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL); > } > -- > 1.8.1 > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
