[PATCH v2 19/21] ext4, jbd2: report fast commit write errors with BH_Write_EIO

[Chao Shi <coshi036@gmail.com>]

ext4_end_buffer_io_sync() is the third completion handler in this
series that reports a failed write by clearing BH_Uptodate, and
jbd2_fc_wait_bufs() is the only thing that looks at the result.
Convert both.

Like the jbd2 handler, this one stops touching BH_Uptodate at all.
ext4_fc_submit_bh() marks the buffer up to date before submitting, so
setting it again on completion said nothing.  The local flag and the debug
messages are reworded to describe the write rather than the buffer's
contents, which the write does not change.

They have to move in the same patch.  The handler lives in ext4 and
the wait in jbd2, but neither is used by anything else: the buffers
are ext4's fast commit blocks, submitted by ext4_fc_submit_bh() and
waited for by jbd2_fc_wait_bufs().  Converting one without the other
silently disables fast commit write error reporting.

Acked-by: Weidong Zhu <weizhu@fiu.edu>
Signed-off-by: Chao Shi <coshi036@gmail.com>
---
 fs/ext4/fast_commit.c | 11 +++++------
 fs/jbd2/journal.c     |  2 +-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 8e2259799614..a2028fbd4540 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -203,17 +203,16 @@ static inline void ext4_fc_set_snap_err(int *snap_err, int err)
 static void ext4_end_buffer_io_sync(struct bio *bio)
 {
 	struct buffer_head *bh;
-	bool uptodate = bio_endio_bh(bio, &bh);
+	bool success = bio_endio_bh(bio, &bh);
 
 	BUFFER_TRACE(bh, "");
-	if (uptodate) {
-		ext4_debug("%s: Block %lld up-to-date",
+	if (success) {
+		ext4_debug("%s: Block %lld written",
 			   __func__, bh->b_blocknr);
-		set_buffer_uptodate(bh);
 	} else {
-		ext4_debug("%s: Block %lld not up-to-date",
+		ext4_debug("%s: Block %lld write failed",
 			   __func__, bh->b_blocknr);
-		clear_buffer_uptodate(bh);
+		mark_buffer_write_io_error(bh);
 	}
 
 	unlock_buffer(bh);
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 6e05dc47e20a..72e8ccbf7de4 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -886,7 +886,7 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
 		 * Update j_fc_off so jbd2_fc_release_bufs can release remain
 		 * buffer head.
 		 */
-		if (unlikely(!buffer_uptodate(bh))) {
+		if (unlikely(buffer_write_io_error(bh))) {
 			journal->j_fc_off = i + 1;
 			return -EIO;
 		}
-- 
2.43.0