From: Chris Mason <mason@suse.com>

Sometimes barriers fail asynchronously (after the submit_bh call).  This
patch changes both ext3 and reiserfs to handle that without mistaking the
barrier failures for io errors.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 25-akpm/fs/jbd/commit.c       |   13 +++++++++++--
 25-akpm/fs/reiserfs/journal.c |   13 +++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff -puN fs/jbd/commit.c~handle-async-barrier-failures fs/jbd/commit.c
--- 25/fs/jbd/commit.c~handle-async-barrier-failures	Thu Jun 10 13:38:30 2004
+++ 25-akpm/fs/jbd/commit.c	Thu Jun 10 13:38:30 2004
@@ -640,12 +640,20 @@ wait_for_iobuf:
 	{
 		struct buffer_head *bh = jh2bh(descriptor);
 		int ret;
+		int barrier_done = 0;
 
 		set_buffer_dirty(bh);
-		if (journal->j_flags & JFS_BARRIER)
+		if (journal->j_flags & JFS_BARRIER) {
 			set_buffer_ordered(bh);
+			barrier_done = 1;
+		}
 		ret = sync_dirty_buffer(bh);
-		if (ret == -EOPNOTSUPP && (journal->j_flags & JFS_BARRIER)) {
+		/* is it possible for another commit to fail at roughly
+		 * the same time as this one?  If so, we don't want to
+		 * trust the barrier flag in the super, but instead want
+		 * to remember if we sent a barrier request
+		 */
+		if (ret == -EOPNOTSUPP && barrier_done) {
 			char b[BDEVNAME_SIZE];
 
 			printk(KERN_WARNING
@@ -658,6 +666,7 @@ wait_for_iobuf:
 
 			/* And try again, without the barrier */
 			clear_buffer_ordered(bh);
+			set_buffer_uptodate(bh);
 			set_buffer_dirty(bh);
 			ret = sync_dirty_buffer(bh);
 		}
diff -puN fs/reiserfs/journal.c~handle-async-barrier-failures fs/reiserfs/journal.c
--- 25/fs/reiserfs/journal.c~handle-async-barrier-failures	Thu Jun 10 13:38:30 2004
+++ 25-akpm/fs/reiserfs/journal.c	Thu Jun 10 13:38:30 2004
@@ -655,6 +655,17 @@ static int submit_barrier_buffer(struct 
     return submit_bh(WRITE_BARRIER, bh) ;
 }
 
+static void check_barrier_completion(struct super_block *s,
+                                     struct buffer_head *bh) {
+    if (buffer_eopnotsupp(bh)) {
+	clear_buffer_eopnotsupp(bh);
+	disable_barrier(s);
+	set_buffer_uptodate(bh);
+	set_buffer_dirty(bh);
+	sync_dirty_buffer(bh);
+    }
+}
+
 #define CHUNK_SIZE 32
 struct buffer_chunk {
     struct buffer_head *bh[CHUNK_SIZE];
@@ -1032,6 +1043,7 @@ static int flush_commit_list(struct supe
   } else
       wait_on_buffer(jl->j_commit_bh);
 
+  check_barrier_completion(s, jl->j_commit_bh);
   if (!buffer_uptodate(jl->j_commit_bh)) {
     reiserfs_panic(s, "journal-615: buffer write failed\n") ;
   }
@@ -1142,6 +1154,7 @@ static int _update_journal_header_block(
 	    goto sync;
 	}
 	wait_on_buffer(SB_JOURNAL(p_s_sb)->j_header_bh);
+	check_barrier_completion(p_s_sb, SB_JOURNAL(p_s_sb)->j_header_bh);
     } else {
 sync:
 	set_buffer_dirty(SB_JOURNAL(p_s_sb)->j_header_bh) ;
_