[PATCH 1/1] NFSD: fix leak referent count of nfsd4_ssc_umount_item in nfsd4_copy

[PATCH 1/1] NFSD: fix leak referent count of nfsd4_ssc_umount_item in nfsd4_copy

[Dai Ngo]

The reference count of nfsd4_ssc_umount_item is not decremented
on error conditions. This prevents the laundromat from unmounting
the vfsmount of the source file.

This patch decrements the reference count of nfsd4_ssc_umount_item
on error.

Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4proc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index b4e7e18e1761..889b603619c3 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1821,13 +1821,17 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 out:
 	return status;
 out_err:
+	if (nfsd4_ssc_is_inter(copy)) {
+		/*
+		 * Source's vfsmount of inter-copy will be unmounted
+		 * by the laundromat. Use copy instead of async_copy
+		 * since async_copy->ss_nsui might not be set yet.
+	 	*/
+		refcount_dec(&copy->ss_nsui->nsui_refcnt);
+	}
 	if (async_copy)
 		cleanup_async_copy(async_copy);
 	status = nfserrno(-ENOMEM);
-	/*
-	 * source's vfsmount of inter-copy will be unmounted
-	 * by the laundromat
-	 */
 	goto out;
 }
 
-- 
2.9.5

Re: [PATCH 1/1] NFSD: fix leak referent count of nfsd4_ssc_umount_item in nfsd4_copy

[Jeff Layton]

On Mon, 2023-01-23 at 21:34 -0800, Dai Ngo wrote:
> The reference count of nfsd4_ssc_umount_item is not decremented
> on error conditions. This prevents the laundromat from unmounting
> the vfsmount of the source file.
> 
> This patch decrements the reference count of nfsd4_ssc_umount_item
> on error.
> 
> Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/nfs4proc.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b4e7e18e1761..889b603619c3 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1821,13 +1821,17 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>  out:
>  	return status;
>  out_err:
> +	if (nfsd4_ssc_is_inter(copy)) {
> +		/*
> +		 * Source's vfsmount of inter-copy will be unmounted
> +		 * by the laundromat. Use copy instead of async_copy
> +		 * since async_copy->ss_nsui might not be set yet.
> +	 	*/
> +		refcount_dec(&copy->ss_nsui->nsui_refcnt);
> +	}
>  	if (async_copy)
>  		cleanup_async_copy(async_copy);
>  	status = nfserrno(-ENOMEM);
> -	/*
> -	 * source's vfsmount of inter-copy will be unmounted
> -	 * by the laundromat
> -	 */
>  	goto out;
>  }
>  

Looks good.

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

Re: [PATCH 1/1] NFSD: fix leak referent count of nfsd4_ssc_umount_item in nfsd4_copy

[Chuck Lever III]

> On Jan 24, 2023, at 12:34 AM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> The reference count of nfsd4_ssc_umount_item is not decremented
> on error conditions. This prevents the laundromat from unmounting
> the vfsmount of the source file.
> 
> This patch decrements the reference count of nfsd4_ssc_umount_item
> on error.
> 
> Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>

Applied to nfsd-next, thanks!


> ---
> fs/nfsd/nfs4proc.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b4e7e18e1761..889b603619c3 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1821,13 +1821,17 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> out:
> 	return status;
> out_err:
> +	if (nfsd4_ssc_is_inter(copy)) {
> +		/*
> +		 * Source's vfsmount of inter-copy will be unmounted
> +		 * by the laundromat. Use copy instead of async_copy
> +		 * since async_copy->ss_nsui might not be set yet.
> +	 	*/
> +		refcount_dec(&copy->ss_nsui->nsui_refcnt);
> +	}
> 	if (async_copy)
> 		cleanup_async_copy(async_copy);
> 	status = nfserrno(-ENOMEM);
> -	/*
> -	 * source's vfsmount of inter-copy will be unmounted
> -	 * by the laundromat
> -	 */
> 	goto out;
> }
> 
> -- 
> 2.9.5
> 

--
Chuck Lever