Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 857 insertions, 0 deletions

diff --git a/fs/afs/proc.c b/fs/afs/proc.c
new file mode 100644
index 000000000000..9c81b8f7eef0
--- /dev/null
+++ b/fs/afs/proc.c
@@ -0,0 +1,857 @@
+/* proc.c: /proc interface for AFS
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "cell.h"
+#include "volume.h"
+#include <asm/uaccess.h>
+#include "internal.h"
+
+static struct proc_dir_entry *proc_afs;
+
+
+static int afs_proc_cells_open(struct inode *inode, struct file *file);
+static void *afs_proc_cells_start(struct seq_file *p, loff_t *pos);
+static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos);
+static void afs_proc_cells_stop(struct seq_file *p, void *v);
+static int afs_proc_cells_show(struct seq_file *m, void *v);
+static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
+                                    size_t size, loff_t *_pos);
+
+static struct seq_operations afs_proc_cells_ops = {
+        .start  = afs_proc_cells_start,
+        .next   = afs_proc_cells_next,
+        .stop   = afs_proc_cells_stop,
+        .show   = afs_proc_cells_show,
+};
+
+static struct file_operations afs_proc_cells_fops = {
+        .open           = afs_proc_cells_open,
+        .read           = seq_read,
+        .write          = afs_proc_cells_write,
+        .llseek         = seq_lseek,
+        .release        = seq_release,
+};
+
+static int afs_proc_rootcell_open(struct inode *inode, struct file *file);
+static int afs_proc_rootcell_release(struct inode *inode, struct file *file);
+static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
+                                      size_t size, loff_t *_pos);
+static ssize_t afs_proc_rootcell_write(struct file *file,
+                                       const char __user *buf,
+                                       size_t size, loff_t *_pos);
+
+static struct file_operations afs_proc_rootcell_fops = {
+        .open           = afs_proc_rootcell_open,
+        .read           = afs_proc_rootcell_read,
+        .write          = afs_proc_rootcell_write,
+        .llseek         = no_llseek,
+        .release        = afs_proc_rootcell_release
+};
+
+static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file);
+static int afs_proc_cell_volumes_release(struct inode *inode,
+                                         struct file *file);
+static void *afs_proc_cell_volumes_start(struct seq_file *p, loff_t *pos);
+static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
+                                        loff_t *pos);
+static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v);
+static int afs_proc_cell_volumes_show(struct seq_file *m, void *v);
+
+static struct seq_operations afs_proc_cell_volumes_ops = {
+        .start  = afs_proc_cell_volumes_start,
+        .next   = afs_proc_cell_volumes_next,
+        .stop   = afs_proc_cell_volumes_stop,
+        .show   = afs_proc_cell_volumes_show,
+};
+
+static struct file_operations afs_proc_cell_volumes_fops = {
+        .open           = afs_proc_cell_volumes_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = afs_proc_cell_volumes_release,
+};
+
+static int afs_proc_cell_vlservers_open(struct inode *inode,
+                                        struct file *file);
+static int afs_proc_cell_vlservers_release(struct inode *inode,
+                                           struct file *file);
+static void *afs_proc_cell_vlservers_start(struct seq_file *p, loff_t *pos);
+static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
+                                          loff_t *pos);
+static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v);
+static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v);
+
+static struct seq_operations afs_proc_cell_vlservers_ops = {
+        .start  = afs_proc_cell_vlservers_start,
+        .next   = afs_proc_cell_vlservers_next,
+        .stop   = afs_proc_cell_vlservers_stop,
+        .show   = afs_proc_cell_vlservers_show,
+};
+
+static struct file_operations afs_proc_cell_vlservers_fops = {
+        .open           = afs_proc_cell_vlservers_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = afs_proc_cell_vlservers_release,
+};
+
+static int afs_proc_cell_servers_open(struct inode *inode, struct file *file);
+static int afs_proc_cell_servers_release(struct inode *inode,
+                                         struct file *file);
+static void *afs_proc_cell_servers_start(struct seq_file *p, loff_t *pos);
+static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
+                                        loff_t *pos);
+static void afs_proc_cell_servers_stop(struct seq_file *p, void *v);
+static int afs_proc_cell_servers_show(struct seq_file *m, void *v);
+
+static struct seq_operations afs_proc_cell_servers_ops = {
+        .start  = afs_proc_cell_servers_start,
+        .next   = afs_proc_cell_servers_next,
+        .stop   = afs_proc_cell_servers_stop,
+        .show   = afs_proc_cell_servers_show,
+};
+
+static struct file_operations afs_proc_cell_servers_fops = {
+        .open           = afs_proc_cell_servers_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = afs_proc_cell_servers_release,
+};
+
+/*****************************************************************************/
+/*
+ * initialise the /proc/fs/afs/ directory
+ */
+int afs_proc_init(void)
+{
+        struct proc_dir_entry *p;
+
+        _enter("");
+
+        proc_afs = proc_mkdir("fs/afs", NULL);
+        if (!proc_afs)
+                goto error;
+        proc_afs->owner = THIS_MODULE;
+
+        p = create_proc_entry("cells", 0, proc_afs);
+        if (!p)
+                goto error_proc;
+        p->proc_fops = &afs_proc_cells_fops;
+        p->owner = THIS_MODULE;
+
+        p = create_proc_entry("rootcell", 0, proc_afs);
+        if (!p)
+                goto error_cells;
+        p->proc_fops = &afs_proc_rootcell_fops;
+        p->owner = THIS_MODULE;
+
+        _leave(" = 0");
+        return 0;
+
+ error_cells:
+        remove_proc_entry("cells", proc_afs);
+ error_proc:
+        remove_proc_entry("fs/afs", NULL);
+ error:
+        _leave(" = -ENOMEM");
+        return -ENOMEM;
+
+} /* end afs_proc_init() */
+
+/*****************************************************************************/
+/*
+ * clean up the /proc/fs/afs/ directory
+ */
+void afs_proc_cleanup(void)
+{
+        remove_proc_entry("cells", proc_afs);
+
+        remove_proc_entry("fs/afs", NULL);
+
+} /* end afs_proc_cleanup() */
+
+/*****************************************************************************/
+/*
+ * open "/proc/fs/afs/cells" which provides a summary of extant cells
+ */
+static int afs_proc_cells_open(struct inode *inode, struct file *file)
+{
+        struct seq_file *m;
+        int ret;
+
+        ret = seq_open(file, &afs_proc_cells_ops);
+        if (ret < 0)
+                return ret;
+
+        m = file->private_data;
+        m->private = PDE(inode)->data;
+
+        return 0;
+} /* end afs_proc_cells_open() */
+
+/*****************************************************************************/
+/*
+ * set up the iterator to start reading from the cells list and return the
+ * first item
+ */
+static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
+{
+        struct list_head *_p;
+        loff_t pos = *_pos;
+
+        /* lock the list against modification */
+        down_read(&afs_proc_cells_sem);
+
+        /* allow for the header line */
+        if (!pos)
+                return (void *) 1;
+        pos--;
+
+        /* find the n'th element in the list */
+        list_for_each(_p, &afs_proc_cells)
+                if (!pos--)
+                        break;
+
+        return _p != &afs_proc_cells ? _p : NULL;
+} /* end afs_proc_cells_start() */
+
+/*****************************************************************************/
+/*
+ * move to next cell in cells list
+ */
+static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos)
+{
+        struct list_head *_p;
+
+        (*pos)++;
+
+        _p = v;
+        _p = v == (void *) 1 ? afs_proc_cells.next : _p->next;
+
+        return _p != &afs_proc_cells ? _p : NULL;
+} /* end afs_proc_cells_next() */
+
+/*****************************************************************************/
+/*
+ * clean up after reading from the cells list
+ */
+static void afs_proc_cells_stop(struct seq_file *p, void *v)
+{
+        up_read(&afs_proc_cells_sem);
+
+} /* end afs_proc_cells_stop() */
+
+/*****************************************************************************/
+/*
+ * display a header line followed by a load of cell lines
+ */
+static int afs_proc_cells_show(struct seq_file *m, void *v)
+{
+        struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);
+
+        /* display header on line 1 */
+        if (v == (void *) 1) {
+                seq_puts(m, "USE NAME\n");
+                return 0;
+        }
+
+        /* display one cell per line on subsequent lines */
+        seq_printf(m, "%3d %s\n", atomic_read(&cell->usage), cell->name);
+
+        return 0;
+} /* end afs_proc_cells_show() */
+
+/*****************************************************************************/
+/*
+ * handle writes to /proc/fs/afs/cells
+ * - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
+ */
+static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
+                                    size_t size, loff_t *_pos)
+{
+        char *kbuf, *name, *args;
+        int ret;
+
+        /* start by dragging the command into memory */
+        if (size <= 1 || size >= PAGE_SIZE)
+                return -EINVAL;
+
+        kbuf = kmalloc(size + 1, GFP_KERNEL);
+        if (!kbuf)
+                return -ENOMEM;
+
+        ret = -EFAULT;
+        if (copy_from_user(kbuf, buf, size) != 0)
+                goto done;
+        kbuf[size] = 0;
+
+        /* trim to first NL */
+        name = memchr(kbuf, '\n', size);
+        if (name)
+                *name = 0;
+
+        /* split into command, name and argslist */
+        name = strchr(kbuf, ' ');
+        if (!name)
+                goto inval;
+        do {
+                *name++ = 0;
+        } while(*name == ' ');
+        if (!*name)
+                goto inval;
+
+        args = strchr(name, ' ');
+        if (!args)
+                goto inval;
+        do {
+                *args++ = 0;
+        } while(*args == ' ');
+        if (!*args)
+                goto inval;
+
+        /* determine command to perform */
+        _debug("cmd=%s name=%s args=%s", kbuf, name, args);
+
+        if (strcmp(kbuf, "add") == 0) {
+                struct afs_cell *cell;
+                ret = afs_cell_create(name, args, &cell);
+                if (ret < 0)
+                        goto done;
+
+                printk("kAFS: Added new cell '%s'\n", name);
+        }
+        else {
+                goto inval;
+        }
+
+        ret = size;
+
+ done:
+        kfree(kbuf);
+        _leave(" = %d", ret);
+        return ret;
+
+ inval:
+        ret = -EINVAL;
+        printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
+        goto done;
+} /* end afs_proc_cells_write() */
+
+/*****************************************************************************/
+/*
+ * Stubs for /proc/fs/afs/rootcell
+ */
+static int afs_proc_rootcell_open(struct inode *inode, struct file *file)
+{
+        return 0;
+}
+
+static int afs_proc_rootcell_release(struct inode *inode, struct file *file)
+{
+        return 0;
+}
+
+static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
+                                      size_t size, loff_t *_pos)
+{
+        return 0;
+}
+
+/*****************************************************************************/
+/*
+ * handle writes to /proc/fs/afs/rootcell
+ * - to initialize rootcell: echo "cell.name:192.168.231.14"
+ */
+static ssize_t afs_proc_rootcell_write(struct file *file,
+                                       const char __user *buf,
+                                       size_t size, loff_t *_pos)
+{
+        char *kbuf, *s;
+        int ret;
+
+        /* start by dragging the command into memory */
+        if (size <= 1 || size >= PAGE_SIZE)
+                return -EINVAL;
+
+        ret = -ENOMEM;
+        kbuf = kmalloc(size + 1, GFP_KERNEL);
+        if (!kbuf)
+                goto nomem;
+
+        ret = -EFAULT;
+        if (copy_from_user(kbuf, buf, size) != 0)
+                goto infault;
+        kbuf[size] = 0;
+
+        /* trim to first NL */
+        s = memchr(kbuf, '\n', size);
+        if (s)
+                *s = 0;
+
+        /* determine command to perform */
+        _debug("rootcell=%s", kbuf);
+
+        ret = afs_cell_init(kbuf);
+        if (ret >= 0)
+                ret = size;     /* consume everything, always */
+
+ infault:
+        kfree(kbuf);
+ nomem:
+        _leave(" = %d", ret);
+        return ret;
+} /* end afs_proc_rootcell_write() */
+
+/*****************************************************************************/
+/*
+ * initialise /proc/fs/afs/<cell>/
+ */
+int afs_proc_cell_setup(struct afs_cell *cell)
+{
+        struct proc_dir_entry *p;
+
+        _enter("%p{%s}", cell, cell->name);
+
+        cell->proc_dir = proc_mkdir(cell->name, proc_afs);
+        if (!cell->proc_dir)
+                return -ENOMEM;
+
+        p = create_proc_entry("servers", 0, cell->proc_dir);
+        if (!p)
+                goto error_proc;
+        p->proc_fops = &afs_proc_cell_servers_fops;
+        p->owner = THIS_MODULE;
+        p->data = cell;
+
+        p = create_proc_entry("vlservers", 0, cell->proc_dir);
+        if (!p)
+                goto error_servers;
+        p->proc_fops = &afs_proc_cell_vlservers_fops;
+        p->owner = THIS_MODULE;
+        p->data = cell;
+
+        p = create_proc_entry("volumes", 0, cell->proc_dir);
+        if (!p)
+                goto error_vlservers;
+        p->proc_fops = &afs_proc_cell_volumes_fops;
+        p->owner = THIS_MODULE;
+        p->data = cell;
+
+        _leave(" = 0");
+        return 0;
+
+ error_vlservers:
+        remove_proc_entry("vlservers", cell->proc_dir);
+ error_servers:
+        remove_proc_entry("servers", cell->proc_dir);
+ error_proc:
+        remove_proc_entry(cell->name, proc_afs);
+        _leave(" = -ENOMEM");
+        return -ENOMEM;
+} /* end afs_proc_cell_setup() */
+
+/*****************************************************************************/
+/*
+ * remove /proc/fs/afs/<cell>/
+ */
+void afs_proc_cell_remove(struct afs_cell *cell)
+{
+        _enter("");
+
+        remove_proc_entry("volumes", cell->proc_dir);
+        remove_proc_entry("vlservers", cell->proc_dir);
+        remove_proc_entry("servers", cell->proc_dir);
+        remove_proc_entry(cell->name, proc_afs);
+
+        _leave("");
+} /* end afs_proc_cell_remove() */
+
+/*****************************************************************************/
+/*
+ * open "/proc/fs/afs/<cell>/volumes" which provides a summary of extant cells
+ */
+static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file)
+{
+        struct afs_cell *cell;
+        struct seq_file *m;
+        int ret;
+
+        cell = afs_get_cell_maybe((struct afs_cell **) &PDE(inode)->data);
+        if (!cell)
+                return -ENOENT;
+
+        ret = seq_open(file, &afs_proc_cell_volumes_ops);
+        if (ret < 0)
+                return ret;
+
+        m = file->private_data;
+        m->private = cell;
+
+        return 0;
+} /* end afs_proc_cell_volumes_open() */
+
+/*****************************************************************************/
+/*
+ * close the file and release the ref to the cell
+ */
+static int afs_proc_cell_volumes_release(struct inode *inode, struct file *file)
+{
+        struct afs_cell *cell = PDE(inode)->data;
+        int ret;
+
+        ret = seq_release(inode,file);
+
+        afs_put_cell(cell);
+
+        return ret;
+} /* end afs_proc_cell_volumes_release() */
+
+/*****************************************************************************/
+/*
+ * set up the iterator to start reading from the cells list and return the
+ * first item
+ */
+static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
+{
+        struct list_head *_p;
+        struct afs_cell *cell = m->private;
+        loff_t pos = *_pos;
+
+        _enter("cell=%p pos=%Ld", cell, *_pos);
+
+        /* lock the list against modification */
+        down_read(&cell->vl_sem);
+
+        /* allow for the header line */
+        if (!pos)
+                return (void *) 1;
+        pos--;
+
+        /* find the n'th element in the list */
+        list_for_each(_p, &cell->vl_list)
+                if (!pos--)
+                        break;
+
+        return _p != &cell->vl_list ? _p : NULL;
+} /* end afs_proc_cell_volumes_start() */
+
+/*****************************************************************************/
+/*
+ * move to next cell in cells list
+ */
+static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
+                                        loff_t *_pos)
+{
+        struct list_head *_p;
+        struct afs_cell *cell = p->private;
+
+        _enter("cell=%p pos=%Ld", cell, *_pos);
+
+        (*_pos)++;
+
+        _p = v;
+        _p = v == (void *) 1 ? cell->vl_list.next : _p->next;
+
+        return _p != &cell->vl_list ? _p : NULL;
+} /* end afs_proc_cell_volumes_next() */
+
+/*****************************************************************************/
+/*
+ * clean up after reading from the cells list
+ */
+static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v)
+{
+        struct afs_cell *cell = p->private;
+
+        up_read(&cell->vl_sem);
+
+} /* end afs_proc_cell_volumes_stop() */
+
+/*****************************************************************************/
+/*
+ * display a header line followed by a load of volume lines
+ */
+static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
+{
+        struct afs_vlocation *vlocation =
+                list_entry(v, struct afs_vlocation, link);
+
+        /* display header on line 1 */
+        if (v == (void *) 1) {
+                seq_puts(m, "USE VLID[0]  VLID[1]  VLID[2]  NAME\n");
+                return 0;
+        }
+
+        /* display one cell per line on subsequent lines */
+        seq_printf(m, "%3d %08x %08x %08x %s\n",
+                   atomic_read(&vlocation->usage),
+                   vlocation->vldb.vid[0],
+                   vlocation->vldb.vid[1],
+                   vlocation->vldb.vid[2],
+                   vlocation->vldb.name
+                   );
+
+        return 0;
+} /* end afs_proc_cell_volumes_show() */
+
+/*****************************************************************************/
+/*
+ * open "/proc/fs/afs/<cell>/vlservers" which provides a list of volume
+ * location server
+ */
+static int afs_proc_cell_vlservers_open(struct inode *inode, struct file *file)
+{
+        struct afs_cell *cell;
+        struct seq_file *m;
+        int ret;
+
+        cell = afs_get_cell_maybe((struct afs_cell**)&PDE(inode)->data);
+        if (!cell)
+                return -ENOENT;
+
+        ret = seq_open(file,&afs_proc_cell_vlservers_ops);
+        if (ret<0)
+                return ret;
+
+        m = file->private_data;
+        m->private = cell;
+
+        return 0;
+} /* end afs_proc_cell_vlservers_open() */
+
+/*****************************************************************************/
+/*
+ * close the file and release the ref to the cell
+ */
+static int afs_proc_cell_vlservers_release(struct inode *inode,
+                                           struct file *file)
+{
+        struct afs_cell *cell = PDE(inode)->data;
+        int ret;
+
+        ret = seq_release(inode,file);
+
+        afs_put_cell(cell);
+
+        return ret;
+} /* end afs_proc_cell_vlservers_release() */
+
+/*****************************************************************************/
+/*
+ * set up the iterator to start reading from the cells list and return the
+ * first item
+ */
+static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
+{
+        struct afs_cell *cell = m->private;
+        loff_t pos = *_pos;
+
+        _enter("cell=%p pos=%Ld", cell, *_pos);
+
+        /* lock the list against modification */
+        down_read(&cell->vl_sem);
+
+        /* allow for the header line */
+        if (!pos)
+                return (void *) 1;
+        pos--;
+
+        if (pos >= cell->vl_naddrs)
+                return NULL;
+
+        return &cell->vl_addrs[pos];
+} /* end afs_proc_cell_vlservers_start() */
+
+/*****************************************************************************/
+/*
+ * move to next cell in cells list
+ */
+static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
+                                          loff_t *_pos)
+{
+        struct afs_cell *cell = p->private;
+        loff_t pos;
+
+        _enter("cell=%p{nad=%u} pos=%Ld", cell, cell->vl_naddrs, *_pos);
+
+        pos = *_pos;
+        (*_pos)++;
+        if (pos >= cell->vl_naddrs)
+                return NULL;
+
+        return &cell->vl_addrs[pos];
+} /* end afs_proc_cell_vlservers_next() */
+
+/*****************************************************************************/
+/*
+ * clean up after reading from the cells list
+ */
+static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v)
+{
+        struct afs_cell *cell = p->private;
+
+        up_read(&cell->vl_sem);
+
+} /* end afs_proc_cell_vlservers_stop() */
+
+/*****************************************************************************/
+/*
+ * display a header line followed by a load of volume lines
+ */
+static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
+{
+        struct in_addr *addr = v;
+
+        /* display header on line 1 */
+        if (v == (struct in_addr *) 1) {
+                seq_puts(m, "ADDRESS\n");
+                return 0;
+        }
+
+        /* display one cell per line on subsequent lines */
+        seq_printf(m, "%u.%u.%u.%u\n", NIPQUAD(addr->s_addr));
+
+        return 0;
+} /* end afs_proc_cell_vlservers_show() */
+
+/*****************************************************************************/
+/*
+ * open "/proc/fs/afs/<cell>/servers" which provides a summary of active
+ * servers
+ */
+static int afs_proc_cell_servers_open(struct inode *inode, struct file *file)
+{
+        struct afs_cell *cell;
+        struct seq_file *m;
+        int ret;
+
+        cell = afs_get_cell_maybe((struct afs_cell **) &PDE(inode)->data);
+        if (!cell)
+                return -ENOENT;
+
+        ret = seq_open(file, &afs_proc_cell_servers_ops);
+        if (ret < 0)
+                return ret;
+
+        m = file->private_data;
+        m->private = cell;
+
+        return 0;
+} /* end afs_proc_cell_servers_open() */
+
+/*****************************************************************************/
+/*
+ * close the file and release the ref to the cell
+ */
+static int afs_proc_cell_servers_release(struct inode *inode,
+                                         struct file *file)
+{
+        struct afs_cell *cell = PDE(inode)->data;
+        int ret;
+
+        ret = seq_release(inode, file);
+
+        afs_put_cell(cell);
+
+        return ret;
+} /* end afs_proc_cell_servers_release() */
+
+/*****************************************************************************/
+/*
+ * set up the iterator to start reading from the cells list and return the
+ * first item
+ */
+static void *afs_proc_cell_servers_start(struct seq_file *m, loff_t *_pos)
+{
+        struct list_head *_p;
+        struct afs_cell *cell = m->private;
+        loff_t pos = *_pos;
+
+        _enter("cell=%p pos=%Ld", cell, *_pos);
+
+        /* lock the list against modification */
+        read_lock(&cell->sv_lock);
+
+        /* allow for the header line */
+        if (!pos)
+                return (void *) 1;
+        pos--;
+
+        /* find the n'th element in the list */
+        list_for_each(_p, &cell->sv_list)
+                if (!pos--)
+                        break;
+
+        return _p != &cell->sv_list ? _p : NULL;
+} /* end afs_proc_cell_servers_start() */
+
+/*****************************************************************************/
+/*
+ * move to next cell in cells list
+ */
+static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
+                                        loff_t *_pos)
+{
+        struct list_head *_p;
+        struct afs_cell *cell = p->private;
+
+        _enter("cell=%p pos=%Ld", cell, *_pos);
+
+        (*_pos)++;
+
+        _p = v;
+        _p = v == (void *) 1 ? cell->sv_list.next : _p->next;
+
+        return _p != &cell->sv_list ? _p : NULL;
+} /* end afs_proc_cell_servers_next() */
+
+/*****************************************************************************/
+/*
+ * clean up after reading from the cells list
+ */
+static void afs_proc_cell_servers_stop(struct seq_file *p, void *v)
+{
+        struct afs_cell *cell = p->private;
+
+        read_unlock(&cell->sv_lock);
+
+} /* end afs_proc_cell_servers_stop() */
+
+/*****************************************************************************/
+/*
+ * display a header line followed by a load of volume lines
+ */
+static int afs_proc_cell_servers_show(struct seq_file *m, void *v)
+{
+        struct afs_server *server = list_entry(v, struct afs_server, link);
+        char ipaddr[20];
+
+        /* display header on line 1 */
+        if (v == (void *) 1) {
+                seq_puts(m, "USE ADDR            STATE\n");
+                return 0;
+        }
+
+        /* display one cell per line on subsequent lines */
+        sprintf(ipaddr, "%u.%u.%u.%u", NIPQUAD(server->addr));
+        seq_printf(m, "%3d %-15.15s %5d\n",
+                   atomic_read(&server->usage),
+                   ipaddr,
+                   server->fs_state
+                   );
+
+        return 0;
+} /* end afs_proc_cell_servers_show() */