ext4: issue fsdev cache flush before starting fast commit

If the journal dev is different from fsdev, issue a cache flush before
committing fast commit blocks to disk.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201106035911.1942128-20-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index fb9b4e9d82b23c4929f5d9ad7a6d013919e66951..ebe5f423f8f2c6358cc104f57ca645561257021c 100644 (file)
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1007,6 +1007,13 @@ static int ext4_fc_perform_commit(journal_t *journal)
        if (ret)
                return ret;
 
+       /*
+        * If file system device is different from journal device, issue a cache
+        * flush before we start writing fast commit blocks.
+        */
+       if (journal->j_fs_dev != journal->j_dev)
+               blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS);
+
        blk_start_plug(&plug);
        if (sbi->s_fc_bytes == 0) {
                /*