nfsd: minor write_pool_threads exit cleanup
[safe/jmp/linux-2.6] / fs / nfsd / nfsctl.c
index e3f9783..b51e7ae 100644 (file)
@@ -60,6 +60,7 @@ enum {
        NFSD_FO_UnlockFS,
        NFSD_Threads,
        NFSD_Pool_Threads,
+       NFSD_Pool_Stats,
        NFSD_Versions,
        NFSD_Ports,
        NFSD_MaxBlkSize,
@@ -84,6 +85,8 @@ static ssize_t write_unexport(struct file *file, char *buf, size_t size);
 static ssize_t write_getfd(struct file *file, char *buf, size_t size);
 static ssize_t write_getfs(struct file *file, char *buf, size_t size);
 static ssize_t write_filehandle(struct file *file, char *buf, size_t size);
+static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size);
+static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size);
 static ssize_t write_threads(struct file *file, char *buf, size_t size);
 static ssize_t write_pool_threads(struct file *file, char *buf, size_t size);
 static ssize_t write_versions(struct file *file, char *buf, size_t size);
@@ -94,9 +97,6 @@ static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
 #endif
 
-static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
-static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);
-
 static ssize_t (*write_op[])(struct file *, char *, size_t) = {
        [NFSD_Svc] = write_svc,
        [NFSD_Add] = write_add,
@@ -106,8 +106,8 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
        [NFSD_Getfd] = write_getfd,
        [NFSD_Getfs] = write_getfs,
        [NFSD_Fh] = write_filehandle,
-       [NFSD_FO_UnlockIP] = failover_unlock_ip,
-       [NFSD_FO_UnlockFS] = failover_unlock_fs,
+       [NFSD_FO_UnlockIP] = write_unlock_ip,
+       [NFSD_FO_UnlockFS] = write_unlock_fs,
        [NFSD_Threads] = write_threads,
        [NFSD_Pool_Threads] = write_pool_threads,
        [NFSD_Versions] = write_versions,
@@ -173,22 +173,74 @@ static const struct file_operations exports_operations = {
        .owner          = THIS_MODULE,
 };
 
+extern int nfsd_pool_stats_open(struct inode *inode, struct file *file);
+
+static struct file_operations pool_stats_operations = {
+       .open           = nfsd_pool_stats_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release,
+       .owner          = THIS_MODULE,
+};
+
 /*----------------------------------------------------------------------------*/
 /*
  * payload - write methods
- * If the method has a response, the response should be put in buf,
- * and the length returned.  Otherwise return 0 or and -error.
  */
 
+/**
+ * write_svc - Start kernel's NFSD server
+ *
+ * Deprecated.  /proc/fs/nfsd/threads is preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_svc
+ *                             svc_port:       port number of this
+ *                                             server's listener
+ *                             svc_nthreads:   number of threads to start
+ *                     size:   size in bytes of passed in nfsctl_svc
+ * Output:
+ *     On success:     returns zero
+ *     On error:       return code is negative errno value
+ */
 static ssize_t write_svc(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_svc *data;
+       int err;
        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_svc*) buf;
-       return nfsd_svc(data->svc_port, data->svc_nthreads);
+       err = nfsd_svc(data->svc_port, data->svc_nthreads);
+       if (err < 0)
+               return err;
+       return 0;
 }
 
+/**
+ * write_add - Add or modify client entry in auth unix cache
+ *
+ * Deprecated.  /proc/net/rpc/auth.unix.ip is preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_client
+ *                             cl_ident:       '\0'-terminated C string
+ *                                             containing domain name
+ *                                             of client
+ *                             cl_naddr:       no. of items in cl_addrlist
+ *                             cl_addrlist:    array of client addresses
+ *                             cl_fhkeytype:   ignored
+ *                             cl_fhkeylen:    ignored
+ *                             cl_fhkey:       ignored
+ *                     size:   size in bytes of passed in nfsctl_client
+ * Output:
+ *     On success:     returns zero
+ *     On error:       return code is negative errno value
+ *
+ * Note: Only AF_INET client addresses are passed in, since
+ * nfsctl_client.cl_addrlist contains only in_addr fields for addresses.
+ */
 static ssize_t write_add(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_client *data;
@@ -198,6 +250,30 @@ static ssize_t write_add(struct file *file, char *buf, size_t size)
        return exp_addclient(data);
 }
 
+/**
+ * write_del - Remove client from auth unix cache
+ *
+ * Deprecated.  /proc/net/rpc/auth.unix.ip is preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_client
+ *                             cl_ident:       '\0'-terminated C string
+ *                                             containing domain name
+ *                                             of client
+ *                             cl_naddr:       ignored
+ *                             cl_addrlist:    ignored
+ *                             cl_fhkeytype:   ignored
+ *                             cl_fhkeylen:    ignored
+ *                             cl_fhkey:       ignored
+ *                     size:   size in bytes of passed in nfsctl_client
+ * Output:
+ *     On success:     returns zero
+ *     On error:       return code is negative errno value
+ *
+ * Note: Only AF_INET client addresses are passed in, since
+ * nfsctl_client.cl_addrlist contains only in_addr fields for addresses.
+ */
 static ssize_t write_del(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_client *data;
@@ -207,6 +283,33 @@ static ssize_t write_del(struct file *file, char *buf, size_t size)
        return exp_delclient(data);
 }
 
+/**
+ * write_export - Export part or all of a local file system
+ *
+ * Deprecated.  /proc/net/rpc/{nfsd.export,nfsd.fh} are preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_export
+ *                             ex_client:      '\0'-terminated C string
+ *                                             containing domain name
+ *                                             of client allowed to access
+ *                                             this export
+ *                             ex_path:        '\0'-terminated C string
+ *                                             containing pathname of
+ *                                             directory in local file system
+ *                             ex_dev:         fsid to use for this export
+ *                             ex_ino:         ignored
+ *                             ex_flags:       export flags for this export
+ *                             ex_anon_uid:    UID to use for anonymous
+ *                                             requests
+ *                             ex_anon_gid:    GID to use for anonymous
+ *                                             requests
+ *                     size:   size in bytes of passed in nfsctl_export
+ * Output:
+ *     On success:     returns zero
+ *     On error:       return code is negative errno value
+ */
 static ssize_t write_export(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_export *data;
@@ -216,6 +319,31 @@ static ssize_t write_export(struct file *file, char *buf, size_t size)
        return exp_export(data);
 }
 
+/**
+ * write_unexport - Unexport a previously exported file system
+ *
+ * Deprecated.  /proc/net/rpc/{nfsd.export,nfsd.fh} are preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_export
+ *                             ex_client:      '\0'-terminated C string
+ *                                             containing domain name
+ *                                             of client no longer allowed
+ *                                             to access this export
+ *                             ex_path:        '\0'-terminated C string
+ *                                             containing pathname of
+ *                                             directory in local file system
+ *                             ex_dev:         ignored
+ *                             ex_ino:         ignored
+ *                             ex_flags:       ignored
+ *                             ex_anon_uid:    ignored
+ *                             ex_anon_gid:    ignored
+ *                     size:   size in bytes of passed in nfsctl_export
+ * Output:
+ *     On success:     returns zero
+ *     On error:       return code is negative errno value
+ */
 static ssize_t write_unexport(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_export *data;
@@ -226,6 +354,30 @@ static ssize_t write_unexport(struct file *file, char *buf, size_t size)
        return exp_unexport(data);
 }
 
+/**
+ * write_getfs - Get a variable-length NFS file handle by path
+ *
+ * Deprecated.  /proc/fs/nfsd/filehandle is preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_fsparm
+ *                             gd_addr:        socket address of client
+ *                             gd_path:        '\0'-terminated C string
+ *                                             containing pathname of
+ *                                             directory in local file system
+ *                             gd_maxlen:      maximum size of returned file
+ *                                             handle
+ *                     size:   size in bytes of passed in nfsctl_fsparm
+ * Output:
+ *     On success:     passed-in buffer filled with a knfsd_fh structure
+ *                     (a variable-length raw NFS file handle);
+ *                     return code is the size in bytes of the file handle
+ *     On error:       return code is negative errno value
+ *
+ * Note: Only AF_INET client addresses are passed in, since gd_addr
+ * is the same size as a struct sockaddr_in.
+ */
 static ssize_t write_getfs(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_fsparm *data;
@@ -265,6 +417,29 @@ static ssize_t write_getfs(struct file *file, char *buf, size_t size)
        return err;
 }
 
+/**
+ * write_getfd - Get a fixed-length NFS file handle by path (used by mountd)
+ *
+ * Deprecated.  /proc/fs/nfsd/filehandle is preferred.
+ * Function remains to support old versions of nfs-utils.
+ *
+ * Input:
+ *                     buf:    struct nfsctl_fdparm
+ *                             gd_addr:        socket address of client
+ *                             gd_path:        '\0'-terminated C string
+ *                                             containing pathname of
+ *                                             directory in local file system
+ *                             gd_version:     fdparm structure version
+ *                     size:   size in bytes of passed in nfsctl_fdparm
+ * Output:
+ *     On success:     passed-in buffer filled with nfsctl_res
+ *                     (a fixed-length raw NFS file handle);
+ *                     return code is the size in bytes of the file handle
+ *     On error:       return code is negative errno value
+ *
+ * Note: Only AF_INET client addresses are passed in, since gd_addr
+ * is the same size as a struct sockaddr_in.
+ */
 static ssize_t write_getfd(struct file *file, char *buf, size_t size)
 {
        struct nfsctl_fdparm *data;
@@ -309,7 +484,23 @@ static ssize_t write_getfd(struct file *file, char *buf, size_t size)
        return err;
 }
 
-static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
+/**
+ * write_unlock_ip - Release all locks used by a client
+ *
+ * Experimental.
+ *
+ * Input:
+ *                     buf:    '\n'-terminated C string containing a
+ *                             presentation format IPv4 address
+ *                     size:   length of C string in @buf
+ * Output:
+ *     On success:     returns zero if all specified locks were released;
+ *                     returns one if one or more locks were not released
+ *     On error:       return code is negative errno value
+ *
+ * Note: Only AF_INET client addresses are passed in
+ */
+static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size)
 {
        struct sockaddr_in sin = {
                .sin_family     = AF_INET,
@@ -330,7 +521,7 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
                return -EINVAL;
 
        /* get ipv4 address */
-       if (sscanf(fo_path, NIPQUAD_FMT "%c", &b1, &b2, &b3, &b4, &c) != 4)
+       if (sscanf(fo_path, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
                return -EINVAL;
        if (b1 > 255 || b2 > 255 || b3 > 255 || b4 > 255)
                return -EINVAL;
@@ -339,7 +530,21 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
        return nlmsvc_unlock_all_by_ip((struct sockaddr *)&sin);
 }
 
-static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
+/**
+ * write_unlock_fs - Release all locks on a local file system
+ *
+ * Experimental.
+ *
+ * Input:
+ *                     buf:    '\n'-terminated C string containing the
+ *                             absolute pathname of a local file system
+ *                     size:   length of C string in @buf
+ * Output:
+ *     On success:     returns zero if all specified locks were released;
+ *                     returns one if one or more locks were not released
+ *     On error:       return code is negative errno value
+ */
+static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)
 {
        struct path path;
        char *fo_path;
@@ -360,21 +565,44 @@ static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
        if (error)
                return error;
 
+       /*
+        * XXX: Needs better sanity checking.  Otherwise we could end up
+        * releasing locks on the wrong file system.
+        *
+        * For example:
+        * 1.  Does the path refer to a directory?
+        * 2.  Is that directory a mount point, or
+        * 3.  Is that directory the root of an exported file system?
+        */
        error = nlmsvc_unlock_all_by_sb(path.mnt->mnt_sb);
 
        path_put(&path);
        return error;
 }
 
+/**
+ * write_filehandle - Get a variable-length NFS file handle by path
+ *
+ * On input, the buffer contains a '\n'-terminated C string comprised of
+ * three alphanumeric words separated by whitespace.  The string may
+ * contain escape sequences.
+ *
+ * Input:
+ *                     buf:
+ *                             domain:         client domain name
+ *                             path:           export pathname
+ *                             maxsize:        numeric maximum size of
+ *                                             @buf
+ *                     size:   length of C string in @buf
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C
+ *                     string containing a ASCII hex text version
+ *                     of the NFS file handle;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is negative errno value
+ */
 static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
 {
-       /* request is:
-        *   domain path maxsize
-        * response is
-        *   filehandle
-        *
-        * qword quoting is used, so filehandle will be \x....
-        */
        char *dname, *path;
        int uninitialized_var(maxsize);
        char *mesg = buf;
@@ -391,11 +619,13 @@ static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
 
        dname = mesg;
        len = qword_get(&mesg, dname, size);
-       if (len <= 0) return -EINVAL;
+       if (len <= 0)
+               return -EINVAL;
        
        path = dname+len+1;
        len = qword_get(&mesg, path, size);
-       if (len <= 0) return -EINVAL;
+       if (len <= 0)
+               return -EINVAL;
 
        len = get_int(&mesg, &maxsize);
        if (len)
@@ -419,17 +649,43 @@ static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
        if (len)
                return len;
        
-       mesg = buf; len = SIMPLE_TRANSACTION_LIMIT;
+       mesg = buf;
+       len = SIMPLE_TRANSACTION_LIMIT;
        qword_addhex(&mesg, &len, (char*)&fh.fh_base, fh.fh_size);
        mesg[-1] = '\n';
        return mesg - buf;      
 }
 
+/**
+ * write_threads - Start NFSD, or report the current number of running threads
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C
+ *                     string numeric value representing the number of
+ *                     running NFSD threads;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing an unsigned
+ *                                     integer value representing the
+ *                                     number of NFSD threads to start
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     NFS service is started;
+ *                     passed-in buffer filled with '\n'-terminated C
+ *                     string numeric value representing the number of
+ *                     running NFSD threads;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_threads(struct file *file, char *buf, size_t size)
 {
-       /* if size > 0, look for a number of threads and call nfsd_svc
-        * then write out number of threads as reply
-        */
        char *mesg = buf;
        int rv;
        if (size > 0) {
@@ -437,16 +693,39 @@ static ssize_t write_threads(struct file *file, char *buf, size_t size)
                rv = get_int(&mesg, &newthreads);
                if (rv)
                        return rv;
-               if (newthreads <0)
+               if (newthreads < 0)
                        return -EINVAL;
-               rv = nfsd_svc(2049, newthreads);
-               if (rv)
+               rv = nfsd_svc(NFS_PORT, newthreads);
+               if (rv < 0)
                        return rv;
-       }
-       sprintf(buf, "%d\n", nfsd_nrthreads());
-       return strlen(buf);
+       } else
+               rv = nfsd_nrthreads();
+
+       return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d\n", rv);
 }
 
+/**
+ * write_pool_threads - Set or report the current number of threads per pool
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing whitespace-
+ *                                     separated unsigned integer values
+ *                                     representing the number of NFSD
+ *                                     threads to start in each pool
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C
+ *                     string containing integer values representing the
+ *                     number of NFSD threads in each pool;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_pool_threads(struct file *file, char *buf, size_t size)
 {
        /* if size > 0, look for an array of number of threads per node
@@ -505,10 +784,7 @@ static ssize_t write_pool_threads(struct file *file, char *buf, size_t size)
                size -= len;
                mesg += len;
        }
-
-       mutex_unlock(&nfsd_mutex);
-       return (mesg-buf);
-
+       rv = mesg - buf;
 out_free:
        kfree(nthreads);
        mutex_unlock(&nfsd_mutex);
@@ -517,13 +793,10 @@ out_free:
 
 static ssize_t __write_versions(struct file *file, char *buf, size_t size)
 {
-       /*
-        * Format:
-        *   [-/+]vers [-/+]vers ...
-        */
        char *mesg = buf;
-       char *vers, sign;
-       int len, num;
+       char *vers, *minorp, sign;
+       int len, num, remaining;
+       unsigned minor;
        ssize_t tlen = 0;
        char *sep;
 
@@ -544,9 +817,20 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                do {
                        sign = *vers;
                        if (sign == '+' || sign == '-')
-                               num = simple_strtol((vers+1), NULL, 0);
+                               num = simple_strtol((vers+1), &minorp, 0);
                        else
-                               num = simple_strtol(vers, NULL, 0);
+                               num = simple_strtol(vers, &minorp, 0);
+                       if (*minorp == '.') {
+                               if (num < 4)
+                                       return -EINVAL;
+                               minor = simple_strtoul(minorp+1, NULL, 0);
+                               if (minor == 0)
+                                       return -EINVAL;
+                               if (nfsd_minorversion(minor, sign == '-' ?
+                                                    NFSD_CLEAR : NFSD_SET) < 0)
+                                       return -EINVAL;
+                               goto next;
+                       }
                        switch(num) {
                        case 2:
                        case 3:
@@ -556,28 +840,86 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                        default:
                                return -EINVAL;
                        }
+               next:
                        vers += len + 1;
-                       tlen += len;
                } while ((len = qword_get(&mesg, vers, size)) > 0);
                /* If all get turned off, turn them back on, as
                 * having no versions is BAD
                 */
                nfsd_reset_versions();
        }
+
        /* Now write current state into reply buffer */
        len = 0;
        sep = "";
+       remaining = SIMPLE_TRANSACTION_LIMIT;
        for (num=2 ; num <= 4 ; num++)
                if (nfsd_vers(num, NFSD_AVAIL)) {
-                       len += sprintf(buf+len, "%s%c%d", sep,
+                       len = snprintf(buf, remaining, "%s%c%d", sep,
                                       nfsd_vers(num, NFSD_TEST)?'+':'-',
                                       num);
                        sep = " ";
+
+                       if (len > remaining)
+                               break;
+                       remaining -= len;
+                       buf += len;
+                       tlen += len;
                }
-       len += sprintf(buf+len, "\n");
-       return len;
+       if (nfsd_vers(4, NFSD_AVAIL))
+               for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION;
+                    minor++) {
+                       len = snprintf(buf, remaining, " %c4.%u",
+                                       (nfsd_vers(4, NFSD_TEST) &&
+                                        nfsd_minorversion(minor, NFSD_TEST)) ?
+                                               '+' : '-',
+                                       minor);
+
+                       if (len > remaining)
+                               break;
+                       remaining -= len;
+                       buf += len;
+                       tlen += len;
+               }
+
+       len = snprintf(buf, remaining, "\n");
+       if (len > remaining)
+               return -EINVAL;
+       return tlen + len;
 }
 
+/**
+ * write_versions - Set or report the available NFS protocol versions
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C
+ *                     string containing positive or negative integer
+ *                     values representing the current status of each
+ *                     protocol version;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing whitespace-
+ *                                     separated positive or negative
+ *                                     integer values representing NFS
+ *                                     protocol versions to enable ("+n")
+ *                                     or disable ("-n")
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     status of zero or more protocol versions has
+ *                     been updated; passed-in buffer filled with
+ *                     '\n'-terminated C string containing positive
+ *                     or negative integer values representing the
+ *                     current status of each protocol version;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_versions(struct file *file, char *buf, size_t size)
 {
        ssize_t rv;
@@ -588,105 +930,217 @@ static ssize_t write_versions(struct file *file, char *buf, size_t size)
        return rv;
 }
 
-static ssize_t __write_ports(struct file *file, char *buf, size_t size)
+/*
+ * Zero-length write.  Return a list of NFSD's current listener
+ * transports.
+ */
+static ssize_t __write_ports_names(char *buf)
 {
-       if (size == 0) {
-               int len = 0;
+       if (nfsd_serv == NULL)
+               return 0;
+       return svc_xprt_names(nfsd_serv, buf, SIMPLE_TRANSACTION_LIMIT);
+}
 
-               if (nfsd_serv)
-                       len = svc_xprt_names(nfsd_serv, buf, 0);
-               return len;
-       }
-       /* Either a single 'fd' number is written, in which
-        * case it must be for a socket of a supported family/protocol,
-        * and we use it as an nfsd socket, or
-        * A '-' followed by the 'name' of a socket in which case
-        * we close the socket.
-        */
-       if (isdigit(buf[0])) {
-               char *mesg = buf;
-               int fd;
-               int err;
-               err = get_int(&mesg, &fd);
-               if (err)
-                       return -EINVAL;
-               if (fd < 0)
-                       return -EINVAL;
-               err = nfsd_create_serv();
-               if (!err) {
-                       err = svc_addsock(nfsd_serv, fd, buf);
-                       if (err >= 0) {
-                               err = lockd_up();
-                               if (err < 0)
-                                       svc_sock_names(buf+strlen(buf)+1, nfsd_serv, buf);
-                       }
-                       /* Decrease the count, but don't shutdown the
-                        * the service
-                        */
-                       nfsd_serv->sv_nrthreads--;
-               }
-               return err < 0 ? err : 0;
-       }
-       if (buf[0] == '-' && isdigit(buf[1])) {
-               char *toclose = kstrdup(buf+1, GFP_KERNEL);
-               int len = 0;
-               if (!toclose)
-                       return -ENOMEM;
-               if (nfsd_serv)
-                       len = svc_sock_names(buf, nfsd_serv, toclose);
-               if (len >= 0)
-                       lockd_down();
-               kfree(toclose);
-               return len;
-       }
-       /*
-        * Add a transport listener by writing it's transport name
-        */
-       if (isalpha(buf[0])) {
-               int err;
-               char transport[16];
-               int port;
-               if (sscanf(buf, "%15s %4d", transport, &port) == 2) {
-                       err = nfsd_create_serv();
-                       if (!err) {
-                               err = svc_create_xprt(nfsd_serv,
-                                                     transport, port,
-                                                     SVC_SOCK_ANONYMOUS);
-                               if (err == -ENOENT)
-                                       /* Give a reasonable perror msg for
-                                        * bad transport string */
-                                       err = -EPROTONOSUPPORT;
-                       }
-                       return err < 0 ? err : 0;
-               }
-       }
-       /*
-        * Remove a transport by writing it's transport name and port number
-        */
-       if (buf[0] == '-' && isalpha(buf[1])) {
-               struct svc_xprt *xprt;
-               int err = -EINVAL;
-               char transport[16];
-               int port;
-               if (sscanf(&buf[1], "%15s %4d", transport, &port) == 2) {
-                       if (port == 0)
-                               return -EINVAL;
-                       if (nfsd_serv) {
-                               xprt = svc_find_xprt(nfsd_serv, transport,
-                                                    AF_UNSPEC, port);
-                               if (xprt) {
-                                       svc_close_xprt(xprt);
-                                       svc_xprt_put(xprt);
-                                       err = 0;
-                               } else
-                                       err = -ENOTCONN;
-                       }
-                       return err < 0 ? err : 0;
-               }
+/*
+ * A single 'fd' number was written, in which case it must be for
+ * a socket of a supported family/protocol, and we use it as an
+ * nfsd listener.
+ */
+static ssize_t __write_ports_addfd(char *buf)
+{
+       char *mesg = buf;
+       int fd, err;
+
+       err = get_int(&mesg, &fd);
+       if (err != 0 || fd < 0)
+               return -EINVAL;
+
+       err = nfsd_create_serv();
+       if (err != 0)
+               return err;
+
+       err = lockd_up();
+       if (err != 0)
+               goto out;
+
+       err = svc_addsock(nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);
+       if (err < 0)
+               lockd_down();
+
+out:
+       /* Decrease the count, but don't shut down the service */
+       nfsd_serv->sv_nrthreads--;
+       return err;
+}
+
+/*
+ * A '-' followed by the 'name' of a socket means we close the socket.
+ */
+static ssize_t __write_ports_delfd(char *buf)
+{
+       char *toclose;
+       int len = 0;
+
+       toclose = kstrdup(buf + 1, GFP_KERNEL);
+       if (toclose == NULL)
+               return -ENOMEM;
+
+       if (nfsd_serv != NULL)
+               len = svc_sock_names(nfsd_serv, buf,
+                                       SIMPLE_TRANSACTION_LIMIT, toclose);
+       if (len >= 0)
+               lockd_down();
+
+       kfree(toclose);
+       return len;
+}
+
+/*
+ * A transport listener is added by writing it's transport name and
+ * a port number.
+ */
+static ssize_t __write_ports_addxprt(char *buf)
+{
+       char transport[16];
+       int port, err;
+
+       if (sscanf(buf, "%15s %4u", transport, &port) != 2)
+               return -EINVAL;
+
+       if (port < 1 || port > USHORT_MAX)
+               return -EINVAL;
+
+       err = nfsd_create_serv();
+       if (err != 0)
+               return err;
+
+       err = svc_create_xprt(nfsd_serv, transport,
+                               PF_INET, port, SVC_SOCK_ANONYMOUS);
+       if (err < 0) {
+               /* Give a reasonable perror msg for bad transport string */
+               if (err == -ENOENT)
+                       err = -EPROTONOSUPPORT;
+               return err;
        }
+       return 0;
+}
+
+/*
+ * A transport listener is removed by writing a "-", it's transport
+ * name, and it's port number.
+ */
+static ssize_t __write_ports_delxprt(char *buf)
+{
+       struct svc_xprt *xprt;
+       char transport[16];
+       int port;
+
+       if (sscanf(&buf[1], "%15s %4u", transport, &port) != 2)
+               return -EINVAL;
+
+       if (port < 1 || port > USHORT_MAX || nfsd_serv == NULL)
+               return -EINVAL;
+
+       xprt = svc_find_xprt(nfsd_serv, transport, AF_UNSPEC, port);
+       if (xprt == NULL)
+               return -ENOTCONN;
+
+       svc_close_xprt(xprt);
+       svc_xprt_put(xprt);
+       return 0;
+}
+
+static ssize_t __write_ports(struct file *file, char *buf, size_t size)
+{
+       if (size == 0)
+               return __write_ports_names(buf);
+
+       if (isdigit(buf[0]))
+               return __write_ports_addfd(buf);
+
+       if (buf[0] == '-' && isdigit(buf[1]))
+               return __write_ports_delfd(buf);
+
+       if (isalpha(buf[0]))
+               return __write_ports_addxprt(buf);
+
+       if (buf[0] == '-' && isalpha(buf[1]))
+               return __write_ports_delxprt(buf);
+
        return -EINVAL;
 }
 
+/**
+ * write_ports - Pass a socket file descriptor or transport name to listen on
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ * Output:
+ *     On success:     passed-in buffer filled with a '\n'-terminated C
+ *                     string containing a whitespace-separated list of
+ *                     named NFSD listeners;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing an unsigned
+ *                                     integer value representing a bound
+ *                                     but unconnected socket that is to be
+ *                                     used as an NFSD listener; listen(3)
+ *                                     must be called for a SOCK_STREAM
+ *                                     socket, otherwise it is ignored
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     NFS service is started;
+ *                     passed-in buffer filled with a '\n'-terminated C
+ *                     string containing a unique alphanumeric name of
+ *                     the listener;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing a "-" followed
+ *                                     by an integer value representing a
+ *                                     previously passed in socket file
+ *                                     descriptor
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     NFS service no longer listens on that socket;
+ *                     passed-in buffer filled with a '\n'-terminated C
+ *                     string containing a unique name of the listener;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing a transport
+ *                                     name and an unsigned integer value
+ *                                     representing the port to listen on,
+ *                                     separated by whitespace
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     returns zero; NFS service is started
+ *     On error:       return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing a "-" followed
+ *                                     by a transport name and an unsigned
+ *                                     integer value representing the port
+ *                                     to listen on, separated by whitespace
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     returns zero; NFS service no longer listens
+ *                     on that transport
+ *     On error:       return code is a negative errno value
+ */
 static ssize_t write_ports(struct file *file, char *buf, size_t size)
 {
        ssize_t rv;
@@ -700,6 +1154,27 @@ static ssize_t write_ports(struct file *file, char *buf, size_t size)
 
 int nfsd_max_blksize;
 
+/**
+ * write_maxblksize - Set or report the current NFS blksize
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing an unsigned
+ *                                     integer value representing the new
+ *                                     NFS blksize
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C string
+ *                     containing numeric value of the current NFS blksize
+ *                     setting;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
 {
        char *mesg = buf;
@@ -724,7 +1199,9 @@ static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
                nfsd_max_blksize = bsize;
                mutex_unlock(&nfsd_mutex);
        }
-       return sprintf(buf, "%d\n", nfsd_max_blksize);
+
+       return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d\n",
+                                                       nfsd_max_blksize);
 }
 
 #ifdef CONFIG_NFSD_V4
@@ -748,10 +1225,32 @@ static ssize_t __write_leasetime(struct file *file, char *buf, size_t size)
                        return -EINVAL;
                nfs4_reset_lease(lease);
        }
-       sprintf(buf, "%ld\n", nfs4_lease_time());
-       return strlen(buf);
+
+       return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%ld\n",
+                                                       nfs4_lease_time());
 }
 
+/**
+ * write_leasetime - Set or report the current NFSv4 lease time
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing an unsigned
+ *                                     integer value representing the new
+ *                                     NFSv4 lease expiry time
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C
+ *                     string containing unsigned integer value of the
+ *                     current lease expiry time;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
 {
        ssize_t rv;
@@ -784,10 +1283,32 @@ static ssize_t __write_recoverydir(struct file *file, char *buf, size_t size)
 
                status = nfs4_reset_recoverydir(recdir);
        }
-       sprintf(buf, "%s\n", nfs4_recoverydir());
-       return strlen(buf);
+
+       return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%s\n",
+                                                       nfs4_recoverydir());
 }
 
+/**
+ * write_recoverydir - Set or report the pathname of the recovery directory
+ *
+ * Input:
+ *                     buf:            ignored
+ *                     size:           zero
+ *
+ * OR
+ *
+ * Input:
+ *                     buf:            C string containing the pathname
+ *                                     of the directory on a local file
+ *                                     system containing permanent NFSv4
+ *                                     recovery data
+ *                     size:           non-zero length of C string in @buf
+ * Output:
+ *     On success:     passed-in buffer filled with '\n'-terminated C string
+ *                     containing the current recovery pathname setting;
+ *                     return code is the size in bytes of the string
+ *     On error:       return code is zero or a negative errno value
+ */
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
 {
        ssize_t rv;
@@ -823,6 +1344,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
                [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
+               [NFSD_Pool_Stats] = {"pool_stats", &pool_stats_operations, S_IRUGO},
                [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
                [NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},