On 08/08/2014 08:48 PM, Dave Chinner wrote: > On Fri, Aug 08, 2014 at 12:04:40PM -0400, Chris Mason wrote: >> >> xfs is using truncate_pagecache_range to invalidate the page cache >> during DIO writes. The other filesystems are calling >> invalidate_inode_pages2_range >> >> 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 write can zero out part of the page cache >> page, and it is possible the page will stay in cache. >> >> This one is an RFC because it is untested and because I don't understand >> how XFS is dealing with pages the truncate was unable to clear away. >> I'm not able to actually trigger zeros by mixing DIO writes with >> buffered reads. >> >> Signed-off-by: Chris Mason <clm@xxxxxx> >> >> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c >> index 8d25d98..c30c112 100644 >> --- a/fs/xfs/xfs_file.c >> +++ b/fs/xfs/xfs_file.c >> @@ -638,7 +638,10 @@ xfs_file_dio_aio_write( >> pos, -1); >> if (ret) >> goto out; >> - truncate_pagecache_range(VFS_I(ip), pos, -1); >> + >> + /* what do we do if we can't invalidate the pages? */ >> + invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, >> + pos >> PAGE_CACHE_SHIFT, -1); > > I don't think it can on XFS. > > We're holding the XFS_IOLOCK_EXCL, so no other syscall based IO can > dirty pages, all the pages are clean, try_to_free_buffers() will > never fail, no-one can run a truncate operation concurently, and > so on. > > So, I'd just do: > > ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, > pos >> PAGE_CACHE_SHIFT, -1); > WARN_ON_ONCE(ret); > ret = 0; > Since pos is page aligned I agree this should be fine. I'll leave that one to you though, since I don't have a great test case for/against it. -chris _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
