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* [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock
@ 2023-10-26  2:21 Al Viro
  2023-10-27 13:38 ` Jeff Layton
  2023-10-30  2:29 ` Xiubo Li
  0 siblings, 2 replies; 3+ messages in thread
From: Al Viro @ 2023-10-26  2:21 UTC (permalink / raw)
  To: Xiubo Li; +Cc: linux-fsdevel, ceph-devel

[at the moment in viro/vfs.git#fixes]
Use of dget() after we'd dropped ->d_lock is too late - dentry might
be gone by that point.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ceph/mds_client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 615db141b6c4..293b93182955 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -861,8 +861,8 @@ int ceph_wait_on_conflict_unlink(struct dentry *dentry)
 		if (!d_same_name(udentry, pdentry, &dname))
 			goto next;
 
+		found = dget_dlock(udentry);
 		spin_unlock(&udentry->d_lock);
-		found = dget(udentry);
 		break;
 next:
 		spin_unlock(&udentry->d_lock);
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock
  2023-10-26  2:21 [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock Al Viro
@ 2023-10-27 13:38 ` Jeff Layton
  2023-10-30  2:29 ` Xiubo Li
  1 sibling, 0 replies; 3+ messages in thread
From: Jeff Layton @ 2023-10-27 13:38 UTC (permalink / raw)
  To: Al Viro, Xiubo Li; +Cc: linux-fsdevel, ceph-devel

On Thu, 2023-10-26 at 03:21 +0100, Al Viro wrote:
> [at the moment in viro/vfs.git#fixes]
> Use of dget() after we'd dropped ->d_lock is too late - dentry might
> be gone by that point.
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  fs/ceph/mds_client.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 615db141b6c4..293b93182955 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -861,8 +861,8 @@ int ceph_wait_on_conflict_unlink(struct dentry *dentry)
>  		if (!d_same_name(udentry, pdentry, &dname))
>  			goto next;
>  
> +		found = dget_dlock(udentry);
>  		spin_unlock(&udentry->d_lock);
> -		found = dget(udentry);
>  		break;
>  next:
>  		spin_unlock(&udentry->d_lock);

Reviewed-by: Jeff Layton <jlayton@kernel.org>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock
  2023-10-26  2:21 [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock Al Viro
  2023-10-27 13:38 ` Jeff Layton
@ 2023-10-30  2:29 ` Xiubo Li
  1 sibling, 0 replies; 3+ messages in thread
From: Xiubo Li @ 2023-10-30  2:29 UTC (permalink / raw)
  To: Al Viro; +Cc: linux-fsdevel, ceph-devel


On 10/26/23 10:21, Al Viro wrote:
> [at the moment in viro/vfs.git#fixes]
> Use of dget() after we'd dropped ->d_lock is too late - dentry might
> be gone by that point.
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>   fs/ceph/mds_client.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 615db141b6c4..293b93182955 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -861,8 +861,8 @@ int ceph_wait_on_conflict_unlink(struct dentry *dentry)
>   		if (!d_same_name(udentry, pdentry, &dname))
>   			goto next;
>   
> +		found = dget_dlock(udentry);
>   		spin_unlock(&udentry->d_lock);
> -		found = dget(udentry);
>   		break;
>   next:
>   		spin_unlock(&udentry->d_lock);

Good catch.

Thanks Al.

- Xiubo



^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-10-30  2:30 UTC | newest]

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2023-10-26  2:21 [PATCH] ceph_wait_on_conflict_unlink(): grab reference before dropping ->d_lock Al Viro
2023-10-27 13:38 ` Jeff Layton
2023-10-30  2:29 ` Xiubo Li

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