git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 4bf93b50fd04118ac7f33a3c2b8a0a1f9fa80bc9 Mon Sep 17 00:00:00 2001
   2 From: Vyacheslav Dubeyko <slava@dubeyko.com>
   3 Date: Thu, 22 Aug 2013 16:35:45 -0700
   4 Subject: nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection
   5
   6 From: Vyacheslav Dubeyko <slava@dubeyko.com>
   7
   8 commit 4bf93b50fd04118ac7f33a3c2b8a0a1f9fa80bc9 upstream.
   9
  10 Fix the issue with improper counting number of flying bio requests for
  11 BIO_EOPNOTSUPP error detection case.
  12
  13 The sb_nbio must be incremented exactly the same number of times as
  14 complete() function was called (or will be called) because
  15 nilfs_segbuf_wait() will call wail_for_completion() for the number of
  16 times set to sb_nbio:
  17
  18   do {
  19       wait_for_completion(&segbuf->sb_bio_event);
  20   } while (--segbuf->sb_nbio > 0);
  21
  22 Two functions complete() and wait_for_completion() must be called the
  23 same number of times for the same sb_bio_event.  Otherwise,
  24 wait_for_completion() will hang or leak.
  25
  26 Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
  27 Cc: Dan Carpenter <dan.carpenter@oracle.com>
  28 Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
  29 Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
  30 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  31 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  32 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  33
  34 ---
  35  fs/nilfs2/segbuf.c |    2 +-
  36  1 file changed, 1 insertion(+), 1 deletion(-)
  37
  38 --- a/fs/nilfs2/segbuf.c
  39 +++ b/fs/nilfs2/segbuf.c
  40 @@ -376,12 +376,12 @@ static int nilfs_segbuf_submit_bio(struc
  41         bio->bi_private = segbuf;
  42         bio_get(bio);
  43         submit_bio(mode, bio);
  44 +       segbuf->sb_nbio++;
  45         if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
  46                 bio_put(bio);
  47                 err = -EOPNOTSUPP;
  48                 goto failed;
  49         }
  50 -       segbuf->sb_nbio++;
  51         bio_put(bio);
  52
  53         wi->bio = NULL;