ext4: fix data integrity for ext4_sync_fs

Inode's data or non journaled quota may be written w/o jounral so we
_must_ send a barrier at the end of ext4_sync_fs. But it can be
skipped if journal commit will do it for us.

Also fix data integrity for nojournal mode.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 35 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7c8e1713e203..0f77c2e4b888 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -69,6 +69,7 @@ static void ext4_mark_recovery_complete(struct super_block *sb,
 static void ext4_clear_journal_err(struct super_block *sb,
                                    struct ext4_super_block *es);
 static int ext4_sync_fs(struct super_block *sb, int wait);
+static int ext4_sync_fs_nojournal(struct super_block *sb, int wait);
 static int ext4_remount(struct super_block *sb, int *flags, char *data);
 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int ext4_unfreeze(struct super_block *sb);
@@ -1097,6 +1098,7 @@ static const struct super_operations ext4_nojournal_sops = {
         .dirty_inode    = ext4_dirty_inode,
         .drop_inode     = ext4_drop_inode,
         .evict_inode    = ext4_evict_inode,
+        .sync_fs        = ext4_sync_fs_nojournal,
         .put_super      = ext4_put_super,
         .statfs         = ext4_statfs,
         .remount_fs     = ext4_remount,
@@ -4553,6 +4555,7 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
 {
         int ret = 0;
         tid_t target;
+        bool needs_barrier = false;
         struct ext4_sb_info *sbi = EXT4_SB(sb);
 
         trace_ext4_sync_fs(sb, wait);
@@ -4563,10 +4566,41 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
          * no dirty dquots
          */
         dquot_writeback_dquots(sb, -1);
+        /*
+         * Data writeback is possible w/o journal transaction, so barrier must
+         * being sent at the end of the function. But we can skip it if
+         * transaction_commit will do it for us.
+         */
+        target = jbd2_get_latest_transaction(sbi->s_journal);
+        if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
+            !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
+                needs_barrier = true;
+
         if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
                 if (wait)
-                        jbd2_log_wait_commit(sbi->s_journal, target);
+                        ret = jbd2_log_wait_commit(sbi->s_journal, target);
+        }
+        if (needs_barrier) {
+                int err;
+                err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+                if (!ret)
+                        ret = err;
         }
+
+        return ret;
+}
+
+static int ext4_sync_fs_nojournal(struct super_block *sb, int wait)
+{
+        int ret = 0;
+
+        trace_ext4_sync_fs(sb, wait);
+        flush_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
+        flush_workqueue(EXT4_SB(sb)->unrsv_conversion_wq);
+        dquot_writeback_dquots(sb, -1);
+        if (wait && test_opt(sb, BARRIER))
+                ret = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+
         return ret;
 }