Thread (4 messages) 4 messages, 4 authors, 2013-08-14

Re: [PATCH v3 1/2] nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error

From: Ryusuke Konishi <hidden>
Date: 2013-08-13 16:51:48
Also in: linux-fsdevel

On Tue, 13 Aug 2013 17:50:33 +0400, Vyacheslav Dubeyko wrote:
From: Vyacheslav Dubeyko <slava@dubeyko.com>
Subject: [PATCH v3 1/2] nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error

This patch removes double call of bio_put() in nilfs_end_bio_write()
for the case of BIO_EOPNOTSUPP error detection. The issue was found
by Dan Carpenter and he suggests first version of the fix too.

Reported-by: Dan Carpenter <redacted>
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
CC: Ryusuke Konishi <redacted>
Acked-by: Ryusuke Konishi <redacted>
Tested-by: Ryusuke Konishi <redacted>

I tested this patch by inserting a pseudo EOPNOTSUPP error, and this
actually fixed a crach "kernel BUG at fs/bio.c:498!" due to reference
count underflow of bio_put() that nilfs_end_bio_write() induced.


Andrew, please pick up this bug-fix preferably for this cycle.


Thanks,
Ryusuke Konishi
quoted hunk ↗ jump to hunk
---
 fs/nilfs2/segbuf.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index dc9a913..5bacf46 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -345,8 +345,7 @@ static void nilfs_end_bio_write(struct bio *bio, int err)
 
 	if (err = -EOPNOTSUPP) {
 		set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
-		bio_put(bio);
-		/* to be detected by submit_seg_bio() */
+		/* to be detected by nilfs_segbuf_submit_bio() */
 	}
 
 	if (!uptodate)
-- 
1.7.9.5



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