nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection
Vyacheslav Dubeyko [Thu, 22 Aug 2013 23:35:45 +0000 (16:35 -0700)]
commit 4bf93b50fd04118ac7f33a3c2b8a0a1f9fa80bc9 upstream.

Fix the issue with improper counting number of flying bio requests for
BIO_EOPNOTSUPP error detection case.

The sb_nbio must be incremented exactly the same number of times as
complete() function was called (or will be called) because
nilfs_segbuf_wait() will call wail_for_completion() for the number of
times set to sb_nbio:

  do {
  } while (--segbuf->sb_nbio > 0);

Two functions complete() and wait_for_completion() must be called the
same number of times for the same sb_bio_event.  Otherwise,
wait_for_completion() will hang or leak.

Signed-off-by: Vyacheslav Dubeyko <>
Cc: Dan Carpenter <>
Acked-by: Ryusuke Konishi <>
Tested-by: Ryusuke Konishi <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Greg Kroah-Hartman <>


index 5bacf46..2d8be51 100644 (file)
@@ -376,12 +376,12 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
        bio->bi_private = segbuf;
        submit_bio(mode, bio);
+       segbuf->sb_nbio++;
        if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
                err = -EOPNOTSUPP;
                goto failed;
-       segbuf->sb_nbio++;
        wi->bio = NULL;