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* [PATCH]nilfs2:missing a read lock for segment writer in nilfs_attach_checkpoint()
@ 2009-08-18  6:58 Zhang Qiang
       [not found] ` <4A8A5110.6080806-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
  0 siblings, 1 reply; 2+ messages in thread
From: Zhang Qiang @ 2009-08-18  6:58 UTC (permalink / raw)
  To: users-JrjvKiOkagjYtjvyW6yDsg; +Cc: Zhang Qiang, Zhu Yanhai

'ns_cno' of structure 'the_nilfs' must be protected from segment writer, in other words, 
the caller of nilfs_get_check_point should hold read lock for nilfs->ns_segctor_sem. 
This patch adds the lock/unlock operations in nilfs_attach_checkpoint() when calling 
nilfs_cpfile_get_checkpoint().

Signed-off-by: Zhang Qiang <zhangqiang.buaa-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

---
 fs/nilfs2/super.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 05174c5..55f3d6b 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -371,8 +371,10 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 	if (unlikely(err))
 		goto failed;
 
+	down_read(&nilfs->ns_segctor_sem);
 	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 					  &bh_cp);
+	up_read(&nilfs->ns_segctor_sem);
 	if (unlikely(err)) {
 		if (err == -ENOENT || err == -EINVAL) {
 			printk(KERN_ERR
-- 
1.6.0.6

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH]nilfs2:missing a read lock for segment writer in nilfs_attach_checkpoint()
       [not found] ` <4A8A5110.6080806-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
@ 2009-08-18  9:37   ` Ryusuke Konishi
  0 siblings, 0 replies; 2+ messages in thread
From: Ryusuke Konishi @ 2009-08-18  9:37 UTC (permalink / raw)
  To: users-JrjvKiOkagjYtjvyW6yDsg,
	zhangqiang.buaa-Re5JQEeQqe8AvxtiuMwx3w
  Cc: qiang.z.zhang-ral2JQCrhuEAvxtiuMwx3w,
	yanhai.zhu-VuQAYsv1563Yd54FQh9/CA,
	konishi.ryusuke-Zyj7fXuS5i5L9jVzuh4AOg

Hi,
On Tue, 18 Aug 2009 14:58:24 +0800, Zhang Qiang wrote:
> 'ns_cno' of structure 'the_nilfs' must be protected from segment writer, in other words, 
> the caller of nilfs_get_check_point should hold read lock for nilfs->ns_segctor_sem. 
> This patch adds the lock/unlock operations in nilfs_attach_checkpoint() when calling 
> nilfs_cpfile_get_checkpoint().
> 
> Signed-off-by: Zhang Qiang <zhangqiang.buaa-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> ---
>  fs/nilfs2/super.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index 05174c5..55f3d6b 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -371,8 +371,10 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
>  	if (unlikely(err))
>  		goto failed;
>  
> +	down_read(&nilfs->ns_segctor_sem);
>  	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
>  					  &bh_cp);
> +	up_read(&nilfs->ns_segctor_sem);
>  	if (unlikely(err)) {
>  		if (err == -ENOENT || err == -EINVAL) {
>  			printk(KERN_ERR
> -- 
> 1.6.0.6

Yeah, this is necessary.

Will be applied. Thank you.

Ryusuke Konishi

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2009-08-18  9:37 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
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2009-08-18  6:58 [PATCH]nilfs2:missing a read lock for segment writer in nilfs_attach_checkpoint() Zhang Qiang
     [not found] ` <4A8A5110.6080806-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2009-08-18  9:37   ` Ryusuke Konishi

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