> On Dec 18, 2022, at 7:55 PM, Dai Ngo <dai.ngo@xxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxx>
> ---
> V2: fix compile error when CONFIG_NFSD_V4_2_INTER_SSC not defined.
> Reported by kernel test robot.
Hello Dai - I've looked at this, nothing to comment on so far. I
plan to go over it again sometime this week.
I'd like to hear from others before applying it.
> fs/nfsd/nfs4proc.c | 94 +++++++++++++++++++------------------------------
> fs/nfsd/xdr4.h | 2 +-
> include/linux/nfs_ssc.h | 2 +-
> 3 files changed, 38 insertions(+), 60 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b79ee65ae016..6515b00520bc 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1295,15 +1295,15 @@ 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);
> @@ -1326,12 +1326,12 @@ static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
> 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) {
> @@ -1339,10 +1339,11 @@ static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
> 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,
> @@ -1371,7 +1372,7 @@ 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;
> @@ -1382,7 +1383,6 @@ 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;
> @@ -1390,6 +1390,7 @@ 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;
>
> @@ -1432,10 +1433,10 @@ 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 */
> @@ -1443,15 +1444,12 @@ 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_work(nn, *nsui);
> goto out_free_devname;
> }
> - if (work)
> - nfsd4_ssc_update_dul_work(nn, work, ss_mnt);
> + nfsd4_ssc_update_dul_work(nn, *nsui, ss_mnt);
> out_done:
> status = 0;
> - *mount = ss_mnt;
>
> out_free_devname:
> kfree(dev_name);
> @@ -1474,8 +1472,7 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
> */
> static __be32
> nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
> - struct nfsd4_compound_state *cstate,
> - struct nfsd4_copy *copy, struct vfsmount **mount)
> + struct nfsd4_compound_state *cstate, struct nfsd4_copy *copy)
> {
> struct svc_fh *s_fh = NULL;
> stateid_t *s_stid = ©->cp_src_stateid;
> @@ -1488,7 +1485,8 @@ 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,
> + ©->ss_nsui);
> if (status)
> goto out;
>
> @@ -1506,61 +1504,42 @@ nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
> }
>
> static void
> -nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
> +nfsd4_cleanup_inter_ssc(struct nfsd4_ssc_umount_item *ni, 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);
>
> 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(&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);
> spin_unlock(&nn->nfsd_ssc_lock);
> - if (!found) {
> - mntput(ss_mnt);
> - return;
> - }
> }
>
> #else /* CONFIG_NFSD_V4_2_INTER_SSC */
>
> static __be32
> nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
> - struct nfsd4_compound_state *cstate,
> - struct nfsd4_copy *copy,
> - struct vfsmount **mount)
> + struct nfsd4_compound_state *cstate,
> + 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 *ni, struct file *filp,
> struct nfsd_file *dst)
> {
> }
> @@ -1700,7 +1679,7 @@ 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)
> @@ -1749,8 +1728,8 @@ static int nfsd4_do_async_copy(void *data)
> if (nfsd4_ssc_is_inter(copy)) {
> struct file *filp;
>
> - filp = nfs42_ssc_open(copy->ss_mnt, ©->c_fh,
> - ©->stateid);
> + filp = nfs42_ssc_open(copy->ss_nsui->nsui_vfsmount,
> + ©->c_fh, ©->stateid);
> if (IS_ERR(filp)) {
> switch (PTR_ERR(filp)) {
> case -EBADF:
> @@ -1764,7 +1743,7 @@ 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);
> @@ -1790,8 +1769,7 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> status = nfserr_notsupp;
> goto out;
> }
> - status = nfsd4_setup_inter_ssc(rqstp, cstate, copy,
> - ©->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 0eb00105d845..36c3340c1d54 100644
> --- 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 75843c00f326..22265b1ff080 100644
> --- 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
> --
> 2.9.5
>
--
Chuck Lever
