Patchwork [58/58] nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection

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Submitter Kamal Mostafa
Date Sept. 3, 2013, 4:24 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/272326/
State New
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Kamal Mostafa - Sept. 3, 2013, 4:24 p.m. -stable review patch.  If anyone has any objections, please let me know.


From: Vyacheslav Dubeyko <>

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: Kamal Mostafa <>
 fs/nilfs2/segbuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 5bacf46..2d8be51 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -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;