nfsd4: add a client info file

Add a new nfsd/clients/#/info file with some basic information about
each NFSv4 client.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

3 files changed, 148 insertions, 8 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8f9747d84525..a6c722dc7e5e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2214,6 +2214,41 @@ find_stateid_by_type(struct nfs4_client *cl, stateid_t *t, char typemask)
         return s;
 }
 
+static int client_info_show(struct seq_file *m, void *v)
+{
+        struct inode *inode = m->private;
+        struct nfsdfs_client *nc;
+        struct nfs4_client *clp;
+        u64 clid;
+
+        nc = get_nfsdfs_client(inode);
+        if (!nc)
+                return -ENXIO;
+        clp = container_of(nc, struct nfs4_client, cl_nfsdfs);
+        memcpy(&clid, &clp->cl_clientid, sizeof(clid));
+        seq_printf(m, "clientid: 0x%llx\n", clid);
+        drop_client(clp);
+
+        return 0;
+}
+
+static int client_info_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, client_info_show, inode);
+}
+
+static const struct file_operations client_info_fops = {
+        .open           = client_info_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static const struct tree_descr client_files[] = {
+        [0] = {"info", &client_info_fops, S_IRUSR},
+        [1] = {""},
+};
+
 static struct nfs4_client *create_client(struct xdr_netobj name,
                 struct svc_rqst *rqstp, nfs4_verifier *verf)
 {
@@ -2242,7 +2277,8 @@ static struct nfs4_client *create_client(struct xdr_netobj name,
         clp->cl_cb_session = NULL;
         clp->net = net;
         clp->cl_nfsd_dentry = nfsd_client_mkdir(nn, &clp->cl_nfsdfs,
-                        clp->cl_clientid.cl_id - nn->clientid_base);
+                        clp->cl_clientid.cl_id - nn->clientid_base,
+                        client_files);
         if (!clp->cl_nfsd_dentry) {
                 free_client(clp);
                 return NULL;
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 599d600f0658..4683ba5c69c7 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1208,14 +1208,116 @@ out_err:
         goto out;
 }
 
+static void clear_ncl(struct inode *inode)
+{
+        struct nfsdfs_client *ncl = inode->i_private;
+
+        inode->i_private = NULL;
+        synchronize_rcu();
+        kref_put(&ncl->cl_ref, ncl->cl_release);
+}
+
+
+struct nfsdfs_client *__get_nfsdfs_client(struct inode *inode)
+{
+        struct nfsdfs_client *nc = inode->i_private;
+
+        if (nc)
+                kref_get(&nc->cl_ref);
+        return nc;
+}
+
+struct nfsdfs_client *get_nfsdfs_client(struct inode *inode)
+{
+        struct nfsdfs_client *nc;
+
+        rcu_read_lock();
+        nc = __get_nfsdfs_client(inode);
+        rcu_read_unlock();
+        return nc;
+}
+/* from __rpc_unlink */
+static void nfsdfs_remove_file(struct inode *dir, struct dentry *dentry)
+{
+        int ret;
+
+        clear_ncl(d_inode(dentry));
+        dget(dentry);
+        ret = simple_unlink(dir, dentry);
+        d_delete(dentry);
+        dput(dentry);
+        WARN_ON_ONCE(ret);
+}
+
+static void nfsdfs_remove_files(struct dentry *root)
+{
+        struct dentry *dentry, *tmp;
+
+        list_for_each_entry_safe(dentry, tmp, &root->d_subdirs, d_child) {
+                if (!simple_positive(dentry)) {
+                        WARN_ON_ONCE(1); /* I think this can't happen? */
+                        continue;
+                }
+                nfsdfs_remove_file(d_inode(root), dentry);
+        }
+}
+
+/* XXX: cut'n'paste from simple_fill_super; figure out if we could share
+ * code instead. */
+static  int nfsdfs_create_files(struct dentry *root,
+                                        const struct tree_descr *files)
+{
+        struct inode *dir = d_inode(root);
+        struct inode *inode;
+        struct dentry *dentry;
+        int i;
+
+        inode_lock(dir);
+        for (i = 0; files->name && files->name[0]; i++, files++) {
+                if (!files->name)
+                        continue;
+                dentry = d_alloc_name(root, files->name);
+                if (!dentry)
+                        goto out;
+                inode = nfsd_get_inode(d_inode(root)->i_sb,
+                                        S_IFREG | files->mode);
+                if (!inode) {
+                        dput(dentry);
+                        goto out;
+                }
+                inode->i_fop = files->ops;
+                inode->i_private = __get_nfsdfs_client(dir);
+                d_add(dentry, inode);
+                fsnotify_create(dir, dentry);
+        }
+        inode_unlock(dir);
+        return 0;
+out:
+        nfsdfs_remove_files(root);
+        inode_unlock(dir);
+        return -ENOMEM;
+}
+
 /* on success, returns positive number unique to that client. */
-struct dentry *nfsd_client_mkdir(struct nfsd_net *nn, struct nfsdfs_client *ncl, u32 id)
+struct dentry *nfsd_client_mkdir(struct nfsd_net *nn,
+                struct nfsdfs_client *ncl, u32 id,
+                const struct tree_descr *files)
 {
+        struct dentry *dentry;
         char name[11];
+        int ret;
 
         sprintf(name, "%u", id);
 
-        return nfsd_mkdir(nn->nfsd_client_dir, ncl, name);
+        dentry = nfsd_mkdir(nn->nfsd_client_dir, ncl, name);
+        if (IS_ERR(dentry)) /* XXX: tossing errors? */
+                return NULL;
+        ret = nfsdfs_create_files(dentry, files);
+        if (ret) {
+                nfsd_client_rmdir(dentry);
+                return NULL;
+        }
+        return dentry;
 }
 
 /* Taken from __rpc_rmdir: */
@@ -1223,16 +1325,16 @@ void nfsd_client_rmdir(struct dentry *dentry)
 {
         struct inode *dir = d_inode(dentry->d_parent);
         struct inode *inode = d_inode(dentry);
-        struct nfsdfs_client *ncl = inode->i_private;
         int ret;
 
-        inode->i_private = NULL;
-        synchronize_rcu();
-        kref_put(&ncl->cl_ref, ncl->cl_release);
+        inode_lock(dir);
+        nfsdfs_remove_files(dentry);
+        clear_ncl(inode);
         dget(dentry);
         ret = simple_rmdir(dir, dentry);
         WARN_ON_ONCE(ret);
         d_delete(dentry);
+        inode_unlock(dir);
 }
 
 static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 85525dcbf77d..af2947551e9c 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -92,7 +92,9 @@ struct nfsdfs_client {
         void (*cl_release)(struct kref *kref);
 };
 
-struct dentry *nfsd_client_mkdir(struct nfsd_net *nn, struct nfsdfs_client *ncl, u32 id);
+struct nfsdfs_client *get_nfsdfs_client(struct inode *);
+struct dentry *nfsd_client_mkdir(struct nfsd_net *nn,
+                struct nfsdfs_client *ncl, u32 id, const struct tree_descr *);
 void nfsd_client_rmdir(struct dentry *dentry);
 
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)