> On Jan 5, 2023, at 11:10 AM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
>
> On Tue, Jan 3, 2023 at 11:14 AM Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:
>>
>>
>>
>>> 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.
>
> I have looked at it and logically it seems ok to me.
Thanks! May I add Reviewed-by: ?
> I have tested it
> (sorta. i'm rarely able to finish). But I keep running into the other
> problem (nfsd4_state_shrinker_count soft lockup that's been already
> reported). I find it interesting that only my destination server hits
> the problem (but not the source server). I don't believe this patch
> has anything to do with this problem, but I found it interesting that
> ssc testing seems to trigger it 100%.
Good data point. But Mike says you can revert the delegation recall
patches to make things stable enough to test, if you'd like to try.
>>> 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
--
Chuck Lever
