ocfs2: Avoid direct write if we fall back to buffered I/O

when we fall back to buffered write from direct write, we call
__generic_file_aio_write() but that will end up doing direct write
even we are only prepared to do buffered write because the file
has the O_DIRECT flag set. This is a fix for
https://bugzilla.novell.com/show_bug.cgi?id=591039
revised with Joel's comments.

Signed-off-by: Li Dongyang <lidongyang@novell.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 14 insertions, 11 deletions

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 20e0ee58dd3..a5fbd9cea96 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1982,18 +1982,18 @@ relock:
         /* communicate with ocfs2_dio_end_io */
         ocfs2_iocb_set_rw_locked(iocb, rw_level);
 
-        if (direct_io) {
-                ret = generic_segment_checks(iov, &nr_segs, &ocount,
-                                             VERIFY_READ);
-                if (ret)
-                        goto out_dio;
+        ret = generic_segment_checks(iov, &nr_segs, &ocount,
+                                     VERIFY_READ);
+        if (ret)
+                goto out_dio;
 
-                count = ocount;
-                ret = generic_write_checks(file, ppos, &count,
-                                           S_ISBLK(inode->i_mode));
-                if (ret)
-                        goto out_dio;
+        count = ocount;
+        ret = generic_write_checks(file, ppos, &count,
+                                   S_ISBLK(inode->i_mode));
+        if (ret)
+                goto out_dio;
 
+        if (direct_io) {
                 written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
                                                     ppos, count, ocount);
                 if (written < 0) {
@@ -2008,7 +2008,10 @@ relock:
                         goto out_dio;
                 }
         } else {
-                written = __generic_file_aio_write(iocb, iov, nr_segs, ppos);
+                current->backing_dev_info = file->f_mapping->backing_dev_info;
+                written = generic_file_buffered_write(iocb, iov, nr_segs, *ppos,
+                                                      ppos, count, 0);
+                current->backing_dev_info = NULL;
         }
 
 out_dio: