NFSD: enhance inter-server copy cleanup

[ Upstream commit df24ac7a2e3a9d0bc68f1756a880e50bfe4b4522 ]

Currently nfsd4_setup_inter_ssc returns the vfsmount of the source
server's export when the mount completes. After the copy is done
nfsd4_cleanup_inter_ssc is called with the vfsmount of the source
server and it searches nfsd_ssc_mount_list for a matching entry
to do the clean up.

The problems with this approach are (1) the need to search the
nfsd_ssc_mount_list and (2) the code has to handle the case where
the matching entry is not found which looks ugly.

The enhancement is instead of nfsd4_setup_inter_ssc returning the
vfsmount, it returns the nfsd4_ssc_umount_item which has the
vfsmount embedded in it. When nfsd4_cleanup_inter_ssc is called
it's passed with the nfsd4_ssc_umount_item directly to do the
clean up so no searching is needed and there is no need to handle
the 'not found' case.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ cel: adjusted whitespace and variable/function names ]
Reviewed-by: Olga Kornievskaia <kolga@netapp.com>
Stable-dep-of: 34e8f9ec4c9a ("NFSD: fix leaked reference count of nfsd4_ssc_umount_item")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index ba04ce9..92b63e5 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1306,15 +1306,15 @@ extern void nfs_sb_deactive(struct super_block *sb);
  * setup a work entry in the ssc delayed unmount list.
  */
 static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
-               struct nfsd4_ssc_umount_item **retwork, struct vfsmount **ss_mnt)
+                                 struct nfsd4_ssc_umount_item **nsui)
 {
        struct nfsd4_ssc_umount_item *ni = NULL;
        struct nfsd4_ssc_umount_item *work = NULL;
        struct nfsd4_ssc_umount_item *tmp;
        DEFINE_WAIT(wait);
+       __be32 status = 0;
 
-       *ss_mnt = NULL;
-       *retwork = NULL;
+       *nsui = NULL;
        work = kzalloc(sizeof(*work), GFP_KERNEL);
 try_again:
        spin_lock(&nn->nfsd_ssc_lock);
@@ -1338,12 +1338,12 @@ try_again:
                        finish_wait(&nn->nfsd_ssc_waitq, &wait);
                        goto try_again;
                }
-               *ss_mnt = ni->nsui_vfsmount;
+               *nsui = ni;
                refcount_inc(&ni->nsui_refcnt);
                spin_unlock(&nn->nfsd_ssc_lock);
                kfree(work);
 
-               /* return vfsmount in ss_mnt */
+               /* return vfsmount in (*nsui)->nsui_vfsmount */
                return 0;
        }
        if (work) {
@@ -1351,31 +1351,32 @@ try_again:
                refcount_set(&work->nsui_refcnt, 2);
                work->nsui_busy = true;
                list_add_tail(&work->nsui_list, &nn->nfsd_ssc_mount_list);
-               *retwork = work;
-       }
+               *nsui = work;
+       } else
+               status = nfserr_resource;
        spin_unlock(&nn->nfsd_ssc_lock);
-       return 0;
+       return status;
 }
 
-static void nfsd4_ssc_update_dul_work(struct nfsd_net *nn,
-               struct nfsd4_ssc_umount_item *work, struct vfsmount *ss_mnt)
+static void nfsd4_ssc_update_dul(struct nfsd_net *nn,
+                                struct nfsd4_ssc_umount_item *nsui,
+                                struct vfsmount *ss_mnt)
 {
-       /* set nsui_vfsmount, clear busy flag and wakeup waiters */
        spin_lock(&nn->nfsd_ssc_lock);
-       work->nsui_vfsmount = ss_mnt;
-       work->nsui_busy = false;
+       nsui->nsui_vfsmount = ss_mnt;
+       nsui->nsui_busy = false;
        wake_up_all(&nn->nfsd_ssc_waitq);
        spin_unlock(&nn->nfsd_ssc_lock);
 }
 
-static void nfsd4_ssc_cancel_dul_work(struct nfsd_net *nn,
-               struct nfsd4_ssc_umount_item *work)
+static void nfsd4_ssc_cancel_dul(struct nfsd_net *nn,
+                                struct nfsd4_ssc_umount_item *nsui)
 {
        spin_lock(&nn->nfsd_ssc_lock);
-       list_del(&work->nsui_list);
+       list_del(&nsui->nsui_list);
        wake_up_all(&nn->nfsd_ssc_waitq);
        spin_unlock(&nn->nfsd_ssc_lock);
-       kfree(work);
+       kfree(nsui);
 }
 
 /*
@@ -1383,7 +1384,7 @@ static void nfsd4_ssc_cancel_dul_work(struct nfsd_net *nn,
  */
 static __be32
 nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
-                      struct vfsmount **mount)
+                      struct nfsd4_ssc_umount_item **nsui)
 {
        struct file_system_type *type;
        struct vfsmount *ss_mnt;
@@ -1394,7 +1395,6 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
        char *ipaddr, *dev_name, *raw_data;
        int len, raw_len;
        __be32 status = nfserr_inval;
-       struct nfsd4_ssc_umount_item *work = NULL;
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
        naddr = &nss->u.nl4_addr;
@@ -1402,6 +1402,7 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
                                         naddr->addr_len,
                                         (struct sockaddr *)&tmp_addr,
                                         sizeof(tmp_addr));
+       *nsui = NULL;
        if (tmp_addrlen == 0)
                goto out_err;
 
@@ -1444,10 +1445,10 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
                goto out_free_rawdata;
        snprintf(dev_name, len + 5, "%s%s%s:/", startsep, ipaddr, endsep);
 
-       status = nfsd4_ssc_setup_dul(nn, ipaddr, &work, &ss_mnt);
+       status = nfsd4_ssc_setup_dul(nn, ipaddr, nsui);
        if (status)
                goto out_free_devname;
-       if (ss_mnt)
+       if ((*nsui)->nsui_vfsmount)
                goto out_done;
 
        /* Use an 'internal' mount: SB_KERNMOUNT -> MNT_INTERNAL */
@@ -1455,15 +1456,12 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
        module_put(type->owner);
        if (IS_ERR(ss_mnt)) {
                status = nfserr_nodev;
-               if (work)
-                       nfsd4_ssc_cancel_dul_work(nn, work);
+               nfsd4_ssc_cancel_dul(nn, *nsui);
                goto out_free_devname;
        }
-       if (work)
-               nfsd4_ssc_update_dul_work(nn, work, ss_mnt);
+       nfsd4_ssc_update_dul(nn, *nsui, ss_mnt);
 out_done:
        status = 0;
-       *mount = ss_mnt;
 
 out_free_devname:
        kfree(dev_name);
@@ -1487,7 +1485,7 @@ out_err:
 static __be32
 nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
-                     struct nfsd4_copy *copy, struct vfsmount **mount)
+                     struct nfsd4_copy *copy)
 {
        struct svc_fh *s_fh = NULL;
        stateid_t *s_stid = &copy->cp_src_stateid;
@@ -1500,7 +1498,7 @@ nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
        if (status)
                goto out;
 
-       status = nfsd4_interssc_connect(copy->cp_src, rqstp, mount);
+       status = nfsd4_interssc_connect(copy->cp_src, rqstp, &copy->ss_nsui);
        if (status)
                goto out;
 
@@ -1518,45 +1516,27 @@ out:
 }
 
 static void
-nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
+nfsd4_cleanup_inter_ssc(struct nfsd4_ssc_umount_item *nsui, struct file *filp,
                        struct nfsd_file *dst)
 {
-       bool found = false;
-       long timeout;
-       struct nfsd4_ssc_umount_item *tmp;
-       struct nfsd4_ssc_umount_item *ni = NULL;
        struct nfsd_net *nn = net_generic(dst->nf_net, nfsd_net_id);
+       long timeout = msecs_to_jiffies(nfsd4_ssc_umount_timeout);
 
        nfs42_ssc_close(filp);
        nfsd_file_put(dst);
        fput(filp);
 
-       if (!nn) {
-               mntput(ss_mnt);
-               return;
-       }
        spin_lock(&nn->nfsd_ssc_lock);
-       timeout = msecs_to_jiffies(nfsd4_ssc_umount_timeout);
-       list_for_each_entry_safe(ni, tmp, &nn->nfsd_ssc_mount_list, nsui_list) {
-               if (ni->nsui_vfsmount->mnt_sb == ss_mnt->mnt_sb) {
-                       list_del(&ni->nsui_list);
-                       /*
-                        * vfsmount can be shared by multiple exports,
-                        * decrement refcnt. If the count drops to 1 it
-                        * will be unmounted when nsui_expire expires.
-                        */
-                       refcount_dec(&ni->nsui_refcnt);
-                       ni->nsui_expire = jiffies + timeout;
-                       list_add_tail(&ni->nsui_list, &nn->nfsd_ssc_mount_list);
-                       found = true;
-                       break;
-               }
-       }
+       list_del(&nsui->nsui_list);
+       /*
+        * vfsmount can be shared by multiple exports,
+        * decrement refcnt. If the count drops to 1 it
+        * will be unmounted when nsui_expire expires.
+        */
+       refcount_dec(&nsui->nsui_refcnt);
+       nsui->nsui_expire = jiffies + timeout;
+       list_add_tail(&nsui->nsui_list, &nn->nfsd_ssc_mount_list);
        spin_unlock(&nn->nfsd_ssc_lock);
-       if (!found) {
-               mntput(ss_mnt);
-               return;
-       }
 }
 
 #else /* CONFIG_NFSD_V4_2_INTER_SSC */
@@ -1564,15 +1544,13 @@ nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
 static __be32
 nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
-                     struct nfsd4_copy *copy,
-                     struct vfsmount **mount)
+                     struct nfsd4_copy *copy)
 {
-       *mount = NULL;
        return nfserr_inval;
 }
 
 static void
-nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
+nfsd4_cleanup_inter_ssc(struct nfsd4_ssc_umount_item *nsui, struct file *filp,
                        struct nfsd_file *dst)
 {
 }
@@ -1713,7 +1691,7 @@ static void dup_copy_fields(struct nfsd4_copy *src, struct nfsd4_copy *dst)
        memcpy(dst->cp_src, src->cp_src, sizeof(struct nl4_server));
        memcpy(&dst->stateid, &src->stateid, sizeof(src->stateid));
        memcpy(&dst->c_fh, &src->c_fh, sizeof(src->c_fh));
-       dst->ss_mnt = src->ss_mnt;
+       dst->ss_nsui = src->ss_nsui;
 }
 
 static void cleanup_async_copy(struct nfsd4_copy *copy)
@@ -1762,8 +1740,8 @@ static int nfsd4_do_async_copy(void *data)
        if (nfsd4_ssc_is_inter(copy)) {
                struct file *filp;
 
-               filp = nfs42_ssc_open(copy->ss_mnt, &copy->c_fh,
-                                     &copy->stateid);
+               filp = nfs42_ssc_open(copy->ss_nsui->nsui_vfsmount,
+                                     &copy->c_fh, &copy->stateid);
                if (IS_ERR(filp)) {
                        switch (PTR_ERR(filp)) {
                        case -EBADF:
@@ -1777,7 +1755,7 @@ static int nfsd4_do_async_copy(void *data)
                }
                nfserr = nfsd4_do_copy(copy, filp, copy->nf_dst->nf_file,
                                       false);
-               nfsd4_cleanup_inter_ssc(copy->ss_mnt, filp, copy->nf_dst);
+               nfsd4_cleanup_inter_ssc(copy->ss_nsui, filp, copy->nf_dst);
        } else {
                nfserr = nfsd4_do_copy(copy, copy->nf_src->nf_file,
                                       copy->nf_dst->nf_file, false);
@@ -1803,8 +1781,7 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                        status = nfserr_notsupp;
                        goto out;
                }
-               status = nfsd4_setup_inter_ssc(rqstp, cstate, copy,
-                               &copy->ss_mnt);
+               status = nfsd4_setup_inter_ssc(rqstp, cstate, copy);
                if (status)
                        return nfserr_offload_denied;
        } else {

diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 0eb0010..36c3340 100644 (file)
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -571,7 +571,7 @@ struct nfsd4_copy {
        struct task_struct      *copy_task;
        refcount_t              refcount;
 
-       struct vfsmount         *ss_mnt;
+       struct nfsd4_ssc_umount_item *ss_nsui;
        struct nfs_fh           c_fh;
        nfs4_stateid            stateid;
 };

diff --git a/include/linux/nfs_ssc.h b/include/linux/nfs_ssc.h
index 75843c0..22265b1 100644 (file)
--- a/include/linux/nfs_ssc.h
+++ b/include/linux/nfs_ssc.h
@@ -53,6 +53,7 @@ static inline void nfs42_ssc_close(struct file *filep)
        if (nfs_ssc_client_tbl.ssc_nfs4_ops)
                (*nfs_ssc_client_tbl.ssc_nfs4_ops->sco_close)(filep);
 }
+#endif
 
 struct nfsd4_ssc_umount_item {
        struct list_head nsui_list;
@@ -66,7 +67,6 @@ struct nfsd4_ssc_umount_item {
        struct vfsmount *nsui_vfsmount;
        char nsui_ipaddr[RPC_MAX_ADDRBUFLEN + 1];
 };
-#endif
 
 /*
  * NFS_FS