nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection
authorVyacheslav Dubeyko <slava@dubeyko.com>
Thu, 22 Aug 2013 23:35:45 +0000 (16:35 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 29 Aug 2013 16:47:37 +0000 (09:47 -0700)
commit020269d2c629a12856a5413528328fbd4ff71ca9
tree0f19cb2e8e37657345963666b79b90e79a53f294
parentb0e01ab2f3f31384dd9e1c660e0c9831e717e73c
nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection

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 {
      wait_for_completion(&segbuf->sb_bio_event);
  } 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 <slava@dubeyko.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/nilfs2/segbuf.c