[PATCH 3.16 72/99] ext4, jbd2: ensure panic when aborting with zero errno

[Ben Hutchings]

3.16.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: "zhangyi (F)" <yi.zhang@xxxxxxxxxx>

commit 51f57b01e4a3c7d7bdceffd84de35144e8c538e7 upstream.

JBD2_REC_ERR flag used to indicate the errno has been updated when jbd2
aborted, and then __ext4_abort() and ext4_handle_error() can invoke
panic if ERRORS_PANIC is specified. But if the journal has been aborted
with zero errno, jbd2_journal_abort() didn't set this flag so we can
no longer panic. Fix this by always record the proper errno in the
journal superblock.

Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20191204124614.45424-3-yi.zhang@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/jbd2/checkpoint.c |  2 +-
 fs/jbd2/journal.c    | 15 ++++-----------
 2 files changed, 5 insertions(+), 12 deletions(-)

--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -173,7 +173,7 @@ void __jbd2_log_wait_for_space(journal_t
 				       "journal space in %s\n", __func__,
 				       journal->j_devname);
 				WARN_ON(1);
-				jbd2_journal_abort(journal, 0);
+				jbd2_journal_abort(journal, -EIO);
 			}
 			write_lock(&journal->j_state_lock);
 		} else {
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2106,12 +2106,10 @@ static void __journal_abort_soft (journa
 
 	__jbd2_journal_abort_hard(journal);
 
-	if (errno) {
-		jbd2_journal_update_sb_errno(journal);
-		write_lock(&journal->j_state_lock);
-		journal->j_flags |= JBD2_REC_ERR;
-		write_unlock(&journal->j_state_lock);
-	}
+	jbd2_journal_update_sb_errno(journal);
+	write_lock(&journal->j_state_lock);
+	journal->j_flags |= JBD2_REC_ERR;
+	write_unlock(&journal->j_state_lock);
 }
 
 /**
@@ -2153,11 +2151,6 @@ static void __journal_abort_soft (journa
  * failure to disk.  ext3_error, for example, now uses this
  * functionality.
  *
- * Errors which originate from within the journaling layer will NOT
- * supply an errno; a null errno implies that absolutely no further
- * writes are done to the journal (unless there are any already in
- * progress).
- *
  */
 
 void jbd2_journal_abort(journal_t *journal, int errno)