When a directory delegation is created, have it allocate the necessary
data structures to collect events and run a CB_NOTIFY callback. For now,
the callback_ops are still skeletal. They'll be fleshed out in a
subsequent patch.

Signed-off-by: Jeff Layton <[email protected]>
---
 fs/nfsd/nfs4state.c | 119 +++++++++++++++++++++++++++++++++++++++++++++-------
 fs/nfsd/state.h     |  46 +++++++++++++++++++-
 2 files changed, 149 insertions(+), 16 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 
517ba5595da3be5e130e1978ba30235496efbe01..5d3af33e70e26e59f8bc3d5b44c82beafb4f786b
 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -130,6 +130,7 @@ static void free_session(struct nfsd4_session *);
 static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
 static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
 static const struct nfsd4_callback_ops nfsd4_cb_getattr_ops;
+static const struct nfsd4_callback_ops nfsd4_cb_notify_ops;
 
 static struct workqueue_struct *laundry_wq;
 
@@ -1127,29 +1128,31 @@ static void block_delegations(struct knfsd_fh *fh)
 }
 
 static struct nfs4_delegation *
-alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
-                struct nfs4_clnt_odstate *odstate, u32 dl_type)
+__alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
+                  struct nfs4_clnt_odstate *odstate, u32 dl_type,
+                  void (*sc_free)(struct nfs4_stid *))
 {
        struct nfs4_delegation *dp;
        struct nfs4_stid *stid;
        long n;
 
-       dprintk("NFSD alloc_init_deleg\n");
+       if (delegation_blocked(&fp->fi_fhandle))
+               return NULL;
+
        n = atomic_long_inc_return(&num_delegations);
        if (n < 0 || n > max_delegations)
                goto out_dec;
-       if (delegation_blocked(&fp->fi_fhandle))
-               goto out_dec;
-       stid = nfs4_alloc_stid(clp, deleg_slab, nfs4_free_deleg);
+
+       stid = nfs4_alloc_stid(clp, deleg_slab, sc_free);
        if (stid == NULL)
                goto out_dec;
-       dp = delegstateid(stid);
 
        /*
         * delegation seqid's are never incremented.  The 4.1 special
         * meaning of seqid 0 isn't meaningful, really, but let's avoid
-        * 0 anyway just for consistency and use 1:
+        * 0 anyway just for consistency and use 1.
         */
+       dp = delegstateid(stid);
        dp->dl_stid.sc_stateid.si_generation = 1;
        INIT_LIST_HEAD(&dp->dl_perfile);
        INIT_LIST_HEAD(&dp->dl_perclnt);
@@ -1159,19 +1162,77 @@ alloc_init_deleg(struct nfs4_client *clp, struct 
nfs4_file *fp,
        dp->dl_type = dl_type;
        dp->dl_retries = 1;
        dp->dl_recalled = false;
-       nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
-                     &nfsd4_cb_recall_ops, NFSPROC4_CLNT_CB_RECALL);
-       nfsd4_init_cb(&dp->dl_cb_fattr.ncf_getattr, dp->dl_stid.sc_client,
-                       &nfsd4_cb_getattr_ops, NFSPROC4_CLNT_CB_GETATTR);
-       dp->dl_cb_fattr.ncf_file_modified = false;
        get_nfs4_file(fp);
        dp->dl_stid.sc_file = fp;
+       nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
+                     &nfsd4_cb_recall_ops, NFSPROC4_CLNT_CB_RECALL);
        return dp;
 out_dec:
        atomic_long_dec(&num_delegations);
        return NULL;
 }
 
+static struct nfs4_delegation *
+alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
+                struct nfs4_clnt_odstate *odstate, u32 dl_type)
+{
+       struct nfs4_delegation *dp;
+
+       dprintk("NFSD alloc_init_deleg\n");
+       dp = __alloc_init_deleg(clp, fp, odstate, dl_type, nfs4_free_deleg);
+       if (!dp)
+               return NULL;
+
+       nfsd4_init_cb(&dp->dl_cb_fattr.ncf_getattr, dp->dl_stid.sc_client,
+                       &nfsd4_cb_getattr_ops, NFSPROC4_CLNT_CB_GETATTR);
+       dp->dl_cb_fattr.ncf_file_modified = false;
+       return dp;
+}
+
+static void nfs4_free_dir_deleg(struct nfs4_stid *stid)
+{
+       struct nfs4_delegation  *dp = delegstateid(stid);
+       struct nfsd4_cb_notify *ncn = &dp->dl_cb_notify;
+       int i;
+
+       for (i = 0; i < ncn->ncn_evt_cnt; ++i)
+               nfsd_notify_event_put(ncn->ncn_evt[i]);
+       release_pages(ncn->ncn_pages, NOTIFY4_PAGE_ARRAY_SIZE);
+       kfree(ncn->ncn_nf);
+       nfs4_free_deleg(stid);
+}
+
+static struct nfs4_delegation *
+alloc_init_dir_deleg(struct nfs4_client *clp, struct nfs4_file *fp)
+{
+       struct nfs4_delegation *dp;
+       struct nfsd4_cb_notify *ncn;
+       int npages;
+
+       dp = __alloc_init_deleg(clp, fp, NULL, NFS4_OPEN_DELEGATE_READ, 
nfs4_free_dir_deleg);
+       if (!dp)
+               return NULL;
+
+       ncn = &dp->dl_cb_notify;
+
+       npages = alloc_pages_bulk(GFP_KERNEL, NOTIFY4_PAGE_ARRAY_SIZE, 
ncn->ncn_pages);
+       if (npages != NOTIFY4_PAGE_ARRAY_SIZE) {
+               release_pages(ncn->ncn_pages, npages);
+               nfs4_free_dir_deleg(&dp->dl_stid);
+       }
+
+       ncn->ncn_nf = kcalloc(NOTIFY4_EVENT_QUEUE_SIZE, sizeof(*ncn->ncn_nf), 
GFP_KERNEL);
+       if (!ncn->ncn_nf) {
+               release_pages(ncn->ncn_pages, npages);
+               nfs4_free_dir_deleg(&dp->dl_stid);
+               return NULL;
+       }
+       spin_lock_init(&ncn->ncn_lock);
+       nfsd4_init_cb(&ncn->ncn_cb, dp->dl_stid.sc_client,
+                       &nfsd4_cb_notify_ops, NFSPROC4_CLNT_CB_NOTIFY);
+       return dp;
+}
+
 void
 nfs4_put_stid(struct nfs4_stid *s)
 {
@@ -3272,6 +3333,30 @@ nfsd4_cb_getattr_release(struct nfsd4_callback *cb)
        nfs4_put_stid(&dp->dl_stid);
 }
 
+static int
+nfsd4_cb_notify_done(struct nfsd4_callback *cb,
+                               struct rpc_task *task)
+{
+       switch (task->tk_status) {
+       case -NFS4ERR_DELAY:
+               rpc_delay(task, 2 * HZ);
+               return 0;
+       default:
+               return 1;
+       }
+}
+
+static void
+nfsd4_cb_notify_release(struct nfsd4_callback *cb)
+{
+       struct nfsd4_cb_notify *ncn =
+                       container_of(cb, struct nfsd4_cb_notify, ncn_cb);
+       struct nfs4_delegation *dp =
+                       container_of(ncn, struct nfs4_delegation, dl_cb_notify);
+
+       nfs4_put_stid(&dp->dl_stid);
+}
+
 static const struct nfsd4_callback_ops nfsd4_cb_recall_any_ops = {
        .done           = nfsd4_cb_recall_any_done,
        .release        = nfsd4_cb_recall_any_release,
@@ -3284,6 +3369,12 @@ static const struct nfsd4_callback_ops 
nfsd4_cb_getattr_ops = {
        .opcode         = OP_CB_GETATTR,
 };
 
+static const struct nfsd4_callback_ops nfsd4_cb_notify_ops = {
+       .done           = nfsd4_cb_notify_done,
+       .release        = nfsd4_cb_notify_release,
+       .opcode         = OP_CB_NOTIFY,
+};
+
 static void nfs4_cb_getattr(struct nfs4_cb_fattr *ncf)
 {
        struct nfs4_delegation *dp =
@@ -9514,7 +9605,7 @@ nfsd_get_dir_deleg(struct nfsd4_compound_state *cstate,
 
        /* Try to set up the lease */
        status = -ENOMEM;
-       dp = alloc_init_deleg(clp, fp, NULL, NFS4_OPEN_DELEGATE_READ);
+       dp = alloc_init_dir_deleg(clp, fp);
        if (!dp)
                goto out_delegees;
 
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 
596d0bbf868c0ca2a31fa20f3ac61db66b60636d..507ce4c097c8b601eecb040876412fc2fe3033b2
 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -196,6 +196,44 @@ struct nfs4_cb_fattr {
 #define NOTIFY4_EVENT_QUEUE_SIZE       3
 #define NOTIFY4_PAGE_ARRAY_SIZE                1
 
+struct nfsd_notify_event {
+       refcount_t      ne_ref;         // refcount
+       u32             ne_mask;        // FS_* mask from fsnotify callback
+       struct dentry   *ne_dentry;     // dentry reference to target
+       u32             ne_namelen;     // length of ne_name
+       char            ne_name[];      // name of dentry being changed
+};
+
+static inline struct nfsd_notify_event *nfsd_notify_event_get(struct 
nfsd_notify_event *ne)
+{
+       refcount_inc(&ne->ne_ref);
+       return ne;
+}
+
+static inline void nfsd_notify_event_put(struct nfsd_notify_event *ne)
+{
+       if (refcount_dec_and_test(&ne->ne_ref)) {
+               dput(ne->ne_dentry);
+               kfree(ne);
+       }
+}
+
+/*
+ * Represents a directory delegation. The callback is for handling CB_NOTIFYs.
+ * As notifications from fsnotify come in, allocate a new event, take the 
ncn_lock,
+ * and add it to the ncn_evt queue. The CB_NOTIFY prepare handler will take the
+ * lock, clean out the list and process it.
+ */
+struct nfsd4_cb_notify {
+       spinlock_t                      ncn_lock;       // protects the evt 
queue and count
+       int                             ncn_evt_cnt;    // count of events in 
ncn_evt
+       int                             ncn_nf_cnt;     // count of valid 
entries in ncn_nf
+       struct nfsd_notify_event        *ncn_evt[NOTIFY4_EVENT_QUEUE_SIZE]; // 
list of events
+       struct page                     *ncn_pages[NOTIFY4_PAGE_ARRAY_SIZE]; // 
for encoding
+       struct notify4                  *ncn_nf;        // array of notify4's 
to be sent
+       struct nfsd4_callback           ncn_cb;         // notify4 callback
+};
+
 /*
  * Represents a delegation stateid. The nfs4_client holds references to these
  * and they are put when it is being destroyed or when the delegation is
@@ -232,8 +270,12 @@ struct nfs4_delegation {
        bool                    dl_written;
        bool                    dl_setattr;
 
-       /* for CB_GETATTR */
-       struct nfs4_cb_fattr    dl_cb_fattr;
+       union {
+               /* for CB_GETATTR */
+               struct nfs4_cb_fattr    dl_cb_fattr;
+               /* for CB_NOTIFY */
+               struct nfsd4_cb_notify  dl_cb_notify;
+       };
 
        /* For delegated timestamps */
        struct timespec64       dl_atime;

-- 
2.51.0


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