ext4: pass -ESHUTDOWN code to jbd2 layer

Previously the jbd2 layer assumed that a file system check would be
required after a journal abort.  In the case of the deliberate file
system shutdown, this should not be necessary.  Allow the jbd2 layer
to distinguish between these two cases by using the ESHUTDOWN errno.

Also add proper locking to __journal_abort_soft().
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

fs/ext4/ioctl.c

@@ -493,13 +493,13 @@ static int ext4_shutdown(struct super_block *sb, unsigned long arg)
 		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
 		if (sbi->s_journal && !is_journal_aborted(sbi->s_journal)) {
 			(void) ext4_force_commit(sb);
-			jbd2_journal_abort(sbi->s_journal, 0);
+			jbd2_journal_abort(sbi->s_journal, -ESHUTDOWN);
 		}
 		break;
 	case EXT4_GOING_FLAGS_NOLOGFLUSH:
 		set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
 		if (sbi->s_journal && !is_journal_aborted(sbi->s_journal))
-			jbd2_journal_abort(sbi->s_journal, 0);
+			jbd2_journal_abort(sbi->s_journal, -ESHUTDOWN);
 		break;
 	default:
 		return -EINVAL;

fs/jbd2/journal.c

@@ -1483,12 +1483,15 @@ static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
 void jbd2_journal_update_sb_errno(journal_t *journal)
 {
 	journal_superblock_t *sb = journal->j_superblock;
+	int errcode;
 
 	read_lock(&journal->j_state_lock);
-	jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
-		  journal->j_errno);
-	sb->s_errno    = cpu_to_be32(journal->j_errno);
+	errcode = journal->j_errno;
 	read_unlock(&journal->j_state_lock);
+	if (errcode == -ESHUTDOWN)
+		errcode = 0;
+	jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
+	sb->s_errno    = cpu_to_be32(errcode);
 
 	jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA);
 }
@@ -2105,12 +2108,22 @@ void __jbd2_journal_abort_hard(journal_t *journal)
  * but don't do any other IO. */
 static void __journal_abort_soft (journal_t *journal, int errno)
 {
-	if (journal->j_flags & JBD2_ABORT)
-		return;
+	int old_errno;
 
-	if (!journal->j_errno)
+	write_lock(&journal->j_state_lock);
+	old_errno = journal->j_errno;
+	if (!journal->j_errno || errno == -ESHUTDOWN)
 		journal->j_errno = errno;
 
+	if (journal->j_flags & JBD2_ABORT) {
+		write_unlock(&journal->j_state_lock);
+		if (!old_errno && old_errno != -ESHUTDOWN &&
+		    errno == -ESHUTDOWN)
+			jbd2_journal_update_sb_errno(journal);
+		return;
+	}
+	write_unlock(&journal->j_state_lock);
+
 	__jbd2_journal_abort_hard(journal);
 
 	if (errno) {