Re: [PATCH] fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers

[Markus Trippelsdorf <markus@trippelsdorf.de>]

On 2011.07.23 at 22:38 +0200, Markus Trippelsdorf wrote:
> On 2011.07.23 at 16:26 -0400, Josef Bacik wrote:
> > On 07/23/2011 02:09 PM, Markus Trippelsdorf wrote:
> > > On 2011.06.29 at 14:05 -0400, Josef Bacik wrote:
> > >> Btrfs needs to be able to control how filemap_write_and_wait_range() is called
> > >> in fsync to make it less of a painful operation, so push down taking i_mutex and
> > >> the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
> > >> file systems can drop taking the i_mutex altogether it seems, like ext3 and
> > >> ocfs2.  For correctness sake I just pushed everything down in all cases to make
> > >> sure that we keep the current behavior the same for everybody, and then each
> > >> individual fs maintainer can make up their mind about what to do from there.
> > >
> > > At least the xfs part of this patch is broken.
> > > Running the latest git-kernel bogofilter doesn't work anymore on my xfs
> > > partition. When I run "bogoutil -d wordlist.db" to dump the contents of
> > > the database, it produces no output at all.
> > >
> > 
> > Already fixed and sent a patch out earlier this week.  Thanks,
> 
> No. This happens with your patch already applied. See my other reply.

The following patch fixes the problem for me:

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index cca00f4..2e23e3d 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -881,11 +881,14 @@ xfs_file_aio_write(
 	/* Handle various SYNC-type writes */
 	if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
 		loff_t end = pos + ret - 1;
+		int error;
 
 		xfs_rw_iunlock(ip, iolock);
-		ret = -xfs_file_fsync(file, pos, end,
+		error = -xfs_file_fsync(file, pos, end,
 				      (file->f_flags & __O_SYNC) ? 0 : 1);
 		xfs_rw_ilock(ip, iolock);
+		if (error)
+			ret = error;
 	}
 
 out_unlock:

-- 
Markus