[PATCH] reiserfs: reiserfs_file_write() will lose error code when a 0-length write occurs w/ O_SYNC

When an error occurs in reiserfs_file_write before any data is written, and
O_SYNC is set, the return code of generic_osync_write will overwrite the
error code, losing it.

This patch ensures that generic_osync_inode() doesn't run under an error
condition, losing the error.  This duplicates the logic from
generic_file_buffered_write().
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <mason@suse.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Alexander Zarochentsev <zam@namesys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/reiserfs/file.c

@@ -1546,9 +1546,9 @@ static ssize_t reiserfs_file_write(struct file *file,	/* the file we are going t
 		}
 	}
 
-	if ((file->f_flags & O_SYNC) || IS_SYNC(inode))
-		res =
-		    generic_osync_inode(inode, file->f_mapping,
+	if (likely(res >= 0) &&
+	    (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))))
+		res = generic_osync_inode(inode, file->f_mapping,
 		                          OSYNC_METADATA | OSYNC_DATA);
 
 	mutex_unlock(&inode->i_mutex);