reiserfs: Make flush bios explicitely sync

Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as
synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions.  generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions

Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.

Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3
CC: reiserfs-devel@vger.kernel.org
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index da01f49..39bb1e8 100644 (file)
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -1112,7 +1112,7 @@ static int flush_commit_list(struct super_block *s,
                depth = reiserfs_write_unlock_nested(s);
                if (reiserfs_barrier_flush(s))
                        __sync_dirty_buffer(jl->j_commit_bh,
-                                       REQ_PREFLUSH | REQ_FUA);
+                                       REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
                else
                        sync_dirty_buffer(jl->j_commit_bh);
                reiserfs_write_lock_nested(s, depth);
@@ -1271,7 +1271,7 @@ static int _update_journal_header_block(struct super_block *sb,
 
                if (reiserfs_barrier_flush(sb))
                        __sync_dirty_buffer(journal->j_header_bh,
-                                       REQ_PREFLUSH | REQ_FUA);
+                                       REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
                else
                        sync_dirty_buffer(journal->j_header_bh);