fs/afs/proc.c

   1 /* proc.c: /proc interface for AFS
   2  *
   3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/module.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/seq_file.h>
  17 #include "cell.h"
  18 #include "volume.h"
  19 #include <asm/uaccess.h>
  20 #include "internal.h"
  21
  22 static struct proc_dir_entry *proc_afs;
  23
  24
  25 static int afs_proc_cells_open(struct inode *inode, struct file *file);
  26 static void *afs_proc_cells_start(struct seq_file *p, loff_t *pos);
  27 static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos);
  28 static void afs_proc_cells_stop(struct seq_file *p, void *v);
  29 static int afs_proc_cells_show(struct seq_file *m, void *v);
  30 static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
  31                                     size_t size, loff_t *_pos);
  32
  33 static struct seq_operations afs_proc_cells_ops = {
  34         .start  = afs_proc_cells_start,
  35         .next   = afs_proc_cells_next,
  36         .stop   = afs_proc_cells_stop,
  37         .show   = afs_proc_cells_show,
  38 };
  39
  40 static const struct file_operations afs_proc_cells_fops = {
  41         .open           = afs_proc_cells_open,
  42         .read           = seq_read,
  43         .write          = afs_proc_cells_write,
  44         .llseek         = seq_lseek,
  45         .release        = seq_release,
  46 };
  47
  48 static int afs_proc_rootcell_open(struct inode *inode, struct file *file);
  49 static int afs_proc_rootcell_release(struct inode *inode, struct file *file);
  50 static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
  51                                       size_t size, loff_t *_pos);
  52 static ssize_t afs_proc_rootcell_write(struct file *file,
  53                                        const char __user *buf,
  54                                        size_t size, loff_t *_pos);
  55
  56 static const struct file_operations afs_proc_rootcell_fops = {
  57         .open           = afs_proc_rootcell_open,
  58         .read           = afs_proc_rootcell_read,
  59         .write          = afs_proc_rootcell_write,
  60         .llseek         = no_llseek,
  61         .release        = afs_proc_rootcell_release
  62 };
  63
  64 static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file);
  65 static int afs_proc_cell_volumes_release(struct inode *inode,
  66                                          struct file *file);
  67 static void *afs_proc_cell_volumes_start(struct seq_file *p, loff_t *pos);
  68 static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
  69                                         loff_t *pos);
  70 static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v);
  71 static int afs_proc_cell_volumes_show(struct seq_file *m, void *v);
  72
  73 static struct seq_operations afs_proc_cell_volumes_ops = {
  74         .start  = afs_proc_cell_volumes_start,
  75         .next   = afs_proc_cell_volumes_next,
  76         .stop   = afs_proc_cell_volumes_stop,
  77         .show   = afs_proc_cell_volumes_show,
  78 };
  79
  80 static const struct file_operations afs_proc_cell_volumes_fops = {
  81         .open           = afs_proc_cell_volumes_open,
  82         .read           = seq_read,
  83         .llseek         = seq_lseek,
  84         .release        = afs_proc_cell_volumes_release,
  85 };
  86
  87 static int afs_proc_cell_vlservers_open(struct inode *inode,
  88                                         struct file *file);
  89 static int afs_proc_cell_vlservers_release(struct inode *inode,
  90                                            struct file *file);
  91 static void *afs_proc_cell_vlservers_start(struct seq_file *p, loff_t *pos);
  92 static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
  93                                           loff_t *pos);
  94 static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v);
  95 static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v);
  96
  97 static struct seq_operations afs_proc_cell_vlservers_ops = {
  98         .start  = afs_proc_cell_vlservers_start,
  99         .next   = afs_proc_cell_vlservers_next,
 100         .stop   = afs_proc_cell_vlservers_stop,
 101         .show   = afs_proc_cell_vlservers_show,
 102 };
 103
 104 static const struct file_operations afs_proc_cell_vlservers_fops = {
 105         .open           = afs_proc_cell_vlservers_open,
 106         .read           = seq_read,
 107         .llseek         = seq_lseek,
 108         .release        = afs_proc_cell_vlservers_release,
 109 };
 110
 111 static int afs_proc_cell_servers_open(struct inode *inode, struct file *file);
 112 static int afs_proc_cell_servers_release(struct inode *inode,
 113                                          struct file *file);
 114 static void *afs_proc_cell_servers_start(struct seq_file *p, loff_t *pos);
 115 static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
 116                                         loff_t *pos);
 117 static void afs_proc_cell_servers_stop(struct seq_file *p, void *v);
 118 static int afs_proc_cell_servers_show(struct seq_file *m, void *v);
 119
 120 static struct seq_operations afs_proc_cell_servers_ops = {
 121         .start  = afs_proc_cell_servers_start,
 122         .next   = afs_proc_cell_servers_next,
 123         .stop   = afs_proc_cell_servers_stop,
 124         .show   = afs_proc_cell_servers_show,
 125 };
 126
 127 static const struct file_operations afs_proc_cell_servers_fops = {
 128         .open           = afs_proc_cell_servers_open,
 129         .read           = seq_read,
 130         .llseek         = seq_lseek,
 131         .release        = afs_proc_cell_servers_release,
 132 };
 133
 134 /*****************************************************************************/
 135 /*
 136  * initialise the /proc/fs/afs/ directory
 137  */
 138 int afs_proc_init(void)
 139 {
 140         struct proc_dir_entry *p;
 141
 142         _enter("");
 143
 144         proc_afs = proc_mkdir("fs/afs", NULL);
 145         if (!proc_afs)
 146                 goto error;
 147         proc_afs->owner = THIS_MODULE;
 148
 149         p = create_proc_entry("cells", 0, proc_afs);
 150         if (!p)
 151                 goto error_proc;
 152         p->proc_fops = &afs_proc_cells_fops;
 153         p->owner = THIS_MODULE;
 154
 155         p = create_proc_entry("rootcell", 0, proc_afs);
 156         if (!p)
 157                 goto error_cells;
 158         p->proc_fops = &afs_proc_rootcell_fops;
 159         p->owner = THIS_MODULE;
 160
 161         _leave(" = 0");
 162         return 0;
 163
 164  error_cells:
 165         remove_proc_entry("cells", proc_afs);
 166  error_proc:
 167         remove_proc_entry("fs/afs", NULL);
 168  error:
 169         _leave(" = -ENOMEM");
 170         return -ENOMEM;
 171
 172 } /* end afs_proc_init() */
 173
 174 /*****************************************************************************/
 175 /*
 176  * clean up the /proc/fs/afs/ directory
 177  */
 178 void afs_proc_cleanup(void)
 179 {
 180         remove_proc_entry("cells", proc_afs);
 181
 182         remove_proc_entry("fs/afs", NULL);
 183
 184 } /* end afs_proc_cleanup() */
 185
 186 /*****************************************************************************/
 187 /*
 188  * open "/proc/fs/afs/cells" which provides a summary of extant cells
 189  */
 190 static int afs_proc_cells_open(struct inode *inode, struct file *file)
 191 {
 192         struct seq_file *m;
 193         int ret;
 194
 195         ret = seq_open(file, &afs_proc_cells_ops);
 196         if (ret < 0)
 197                 return ret;
 198
 199         m = file->private_data;
 200         m->private = PDE(inode)->data;
 201
 202         return 0;
 203 } /* end afs_proc_cells_open() */
 204
 205 /*****************************************************************************/
 206 /*
 207  * set up the iterator to start reading from the cells list and return the
 208  * first item
 209  */
 210 static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
 211 {
 212         struct list_head *_p;
 213         loff_t pos = *_pos;
 214
 215         /* lock the list against modification */
 216         down_read(&afs_proc_cells_sem);
 217
 218         /* allow for the header line */
 219         if (!pos)
 220                 return (void *) 1;
 221         pos--;
 222
 223         /* find the n'th element in the list */
 224         list_for_each(_p, &afs_proc_cells)
 225                 if (!pos--)
 226                         break;
 227
 228         return _p != &afs_proc_cells ? _p : NULL;
 229 } /* end afs_proc_cells_start() */
 230
 231 /*****************************************************************************/
 232 /*
 233  * move to next cell in cells list
 234  */
 235 static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos)
 236 {
 237         struct list_head *_p;
 238
 239         (*pos)++;
 240
 241         _p = v;
 242         _p = v == (void *) 1 ? afs_proc_cells.next : _p->next;
 243
 244         return _p != &afs_proc_cells ? _p : NULL;
 245 } /* end afs_proc_cells_next() */
 246
 247 /*****************************************************************************/
 248 /*
 249  * clean up after reading from the cells list
 250  */
 251 static void afs_proc_cells_stop(struct seq_file *p, void *v)
 252 {
 253         up_read(&afs_proc_cells_sem);
 254
 255 } /* end afs_proc_cells_stop() */
 256
 257 /*****************************************************************************/
 258 /*
 259  * display a header line followed by a load of cell lines
 260  */
 261 static int afs_proc_cells_show(struct seq_file *m, void *v)
 262 {
 263         struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);
 264
 265         /* display header on line 1 */
 266         if (v == (void *) 1) {
 267                 seq_puts(m, "USE NAME\n");
 268                 return 0;
 269         }
 270
 271         /* display one cell per line on subsequent lines */
 272         seq_printf(m, "%3d %s\n", atomic_read(&cell->usage), cell->name);
 273
 274         return 0;
 275 } /* end afs_proc_cells_show() */
 276
 277 /*****************************************************************************/
 278 /*
 279  * handle writes to /proc/fs/afs/cells
 280  * - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
 281  */
 282 static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
 283                                     size_t size, loff_t *_pos)
 284 {
 285         char *kbuf, *name, *args;
 286         int ret;
 287
 288         /* start by dragging the command into memory */
 289         if (size <= 1 || size >= PAGE_SIZE)
 290                 return -EINVAL;
 291
 292         kbuf = kmalloc(size + 1, GFP_KERNEL);
 293         if (!kbuf)
 294                 return -ENOMEM;
 295
 296         ret = -EFAULT;
 297         if (copy_from_user(kbuf, buf, size) != 0)
 298                 goto done;
 299         kbuf[size] = 0;
 300
 301         /* trim to first NL */
 302         name = memchr(kbuf, '\n', size);
 303         if (name)
 304                 *name = 0;
 305
 306         /* split into command, name and argslist */
 307         name = strchr(kbuf, ' ');
 308         if (!name)
 309                 goto inval;
 310         do {
 311                 *name++ = 0;
 312         } while(*name == ' ');
 313         if (!*name)
 314                 goto inval;
 315
 316         args = strchr(name, ' ');
 317         if (!args)
 318                 goto inval;
 319         do {
 320                 *args++ = 0;
 321         } while(*args == ' ');
 322         if (!*args)
 323                 goto inval;
 324
 325         /* determine command to perform */
 326         _debug("cmd=%s name=%s args=%s", kbuf, name, args);
 327
 328         if (strcmp(kbuf, "add") == 0) {
 329                 struct afs_cell *cell;
 330                 ret = afs_cell_create(name, args, &cell);
 331                 if (ret < 0)
 332                         goto done;
 333
 334                 printk("kAFS: Added new cell '%s'\n", name);
 335         }
 336         else {
 337                 goto inval;
 338         }
 339
 340         ret = size;
 341
 342  done:
 343         kfree(kbuf);
 344         _leave(" = %d", ret);
 345         return ret;
 346
 347  inval:
 348         ret = -EINVAL;
 349         printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
 350         goto done;
 351 } /* end afs_proc_cells_write() */
 352
 353 /*****************************************************************************/
 354 /*
 355  * Stubs for /proc/fs/afs/rootcell
 356  */
 357 static int afs_proc_rootcell_open(struct inode *inode, struct file *file)
 358 {
 359         return 0;
 360 }
 361
 362 static int afs_proc_rootcell_release(struct inode *inode, struct file *file)
 363 {
 364         return 0;
 365 }
 366
 367 static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
 368                                       size_t size, loff_t *_pos)
 369 {
 370         return 0;
 371 }
 372
 373 /*****************************************************************************/
 374 /*
 375  * handle writes to /proc/fs/afs/rootcell
 376  * - to initialize rootcell: echo "cell.name:192.168.231.14"
 377  */
 378 static ssize_t afs_proc_rootcell_write(struct file *file,
 379                                        const char __user *buf,
 380                                        size_t size, loff_t *_pos)
 381 {
 382         char *kbuf, *s;
 383         int ret;
 384
 385         /* start by dragging the command into memory */
 386         if (size <= 1 || size >= PAGE_SIZE)
 387                 return -EINVAL;
 388
 389         ret = -ENOMEM;
 390         kbuf = kmalloc(size + 1, GFP_KERNEL);
 391         if (!kbuf)
 392                 goto nomem;
 393
 394         ret = -EFAULT;
 395         if (copy_from_user(kbuf, buf, size) != 0)
 396                 goto infault;
 397         kbuf[size] = 0;
 398
 399         /* trim to first NL */
 400         s = memchr(kbuf, '\n', size);
 401         if (s)
 402                 *s = 0;
 403
 404         /* determine command to perform */
 405         _debug("rootcell=%s", kbuf);
 406
 407         ret = afs_cell_init(kbuf);
 408         if (ret >= 0)
 409                 ret = size;     /* consume everything, always */
 410
 411  infault:
 412         kfree(kbuf);
 413  nomem:
 414         _leave(" = %d", ret);
 415         return ret;
 416 } /* end afs_proc_rootcell_write() */
 417
 418 /*****************************************************************************/
 419 /*
 420  * initialise /proc/fs/afs/<cell>/
 421  */
 422 int afs_proc_cell_setup(struct afs_cell *cell)
 423 {
 424         struct proc_dir_entry *p;
 425
 426         _enter("%p{%s}", cell, cell->name);
 427
 428         cell->proc_dir = proc_mkdir(cell->name, proc_afs);
 429         if (!cell->proc_dir)
 430                 return -ENOMEM;
 431
 432         p = create_proc_entry("servers", 0, cell->proc_dir);
 433         if (!p)
 434                 goto error_proc;
 435         p->proc_fops = &afs_proc_cell_servers_fops;
 436         p->owner = THIS_MODULE;
 437         p->data = cell;
 438
 439         p = create_proc_entry("vlservers", 0, cell->proc_dir);
 440         if (!p)
 441                 goto error_servers;
 442         p->proc_fops = &afs_proc_cell_vlservers_fops;
 443         p->owner = THIS_MODULE;
 444         p->data = cell;
 445
 446         p = create_proc_entry("volumes", 0, cell->proc_dir);
 447         if (!p)
 448                 goto error_vlservers;
 449         p->proc_fops = &afs_proc_cell_volumes_fops;
 450         p->owner = THIS_MODULE;
 451         p->data = cell;
 452
 453         _leave(" = 0");
 454         return 0;
 455
 456  error_vlservers:
 457         remove_proc_entry("vlservers", cell->proc_dir);
 458  error_servers:
 459         remove_proc_entry("servers", cell->proc_dir);
 460  error_proc:
 461         remove_proc_entry(cell->name, proc_afs);
 462         _leave(" = -ENOMEM");
 463         return -ENOMEM;
 464 } /* end afs_proc_cell_setup() */
 465
 466 /*****************************************************************************/
 467 /*
 468  * remove /proc/fs/afs/<cell>/
 469  */
 470 void afs_proc_cell_remove(struct afs_cell *cell)
 471 {
 472         _enter("");
 473
 474         remove_proc_entry("volumes", cell->proc_dir);
 475         remove_proc_entry("vlservers", cell->proc_dir);
 476         remove_proc_entry("servers", cell->proc_dir);
 477         remove_proc_entry(cell->name, proc_afs);
 478
 479         _leave("");
 480 } /* end afs_proc_cell_remove() */
 481
 482 /*****************************************************************************/
 483 /*
 484  * open "/proc/fs/afs/<cell>/volumes" which provides a summary of extant cells
 485  */
 486 static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file)
 487 {
 488         struct afs_cell *cell;
 489         struct seq_file *m;
 490         int ret;
 491
 492         cell = afs_get_cell_maybe((struct afs_cell **) &PDE(inode)->data);
 493         if (!cell)
 494                 return -ENOENT;
 495
 496         ret = seq_open(file, &afs_proc_cell_volumes_ops);
 497         if (ret < 0)
 498                 return ret;
 499
 500         m = file->private_data;
 501         m->private = cell;
 502
 503         return 0;
 504 } /* end afs_proc_cell_volumes_open() */
 505
 506 /*****************************************************************************/
 507 /*
 508  * close the file and release the ref to the cell
 509  */
 510 static int afs_proc_cell_volumes_release(struct inode *inode, struct file *file)
 511 {
 512         struct afs_cell *cell = PDE(inode)->data;
 513         int ret;
 514
 515         ret = seq_release(inode,file);
 516
 517         afs_put_cell(cell);
 518
 519         return ret;
 520 } /* end afs_proc_cell_volumes_release() */
 521
 522 /*****************************************************************************/
 523 /*
 524  * set up the iterator to start reading from the cells list and return the
 525  * first item
 526  */
 527 static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
 528 {
 529         struct list_head *_p;
 530         struct afs_cell *cell = m->private;
 531         loff_t pos = *_pos;
 532
 533         _enter("cell=%p pos=%Ld", cell, *_pos);
 534
 535         /* lock the list against modification */
 536         down_read(&cell->vl_sem);
 537
 538         /* allow for the header line */
 539         if (!pos)
 540                 return (void *) 1;
 541         pos--;
 542
 543         /* find the n'th element in the list */
 544         list_for_each(_p, &cell->vl_list)
 545                 if (!pos--)
 546                         break;
 547
 548         return _p != &cell->vl_list ? _p : NULL;
 549 } /* end afs_proc_cell_volumes_start() */
 550
 551 /*****************************************************************************/
 552 /*
 553  * move to next cell in cells list
 554  */
 555 static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
 556                                         loff_t *_pos)
 557 {
 558         struct list_head *_p;
 559         struct afs_cell *cell = p->private;
 560
 561         _enter("cell=%p pos=%Ld", cell, *_pos);
 562
 563         (*_pos)++;
 564
 565         _p = v;
 566         _p = v == (void *) 1 ? cell->vl_list.next : _p->next;
 567
 568         return _p != &cell->vl_list ? _p : NULL;
 569 } /* end afs_proc_cell_volumes_next() */
 570
 571 /*****************************************************************************/
 572 /*
 573  * clean up after reading from the cells list
 574  */
 575 static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v)
 576 {
 577         struct afs_cell *cell = p->private;
 578
 579         up_read(&cell->vl_sem);
 580
 581 } /* end afs_proc_cell_volumes_stop() */
 582
 583 /*****************************************************************************/
 584 /*
 585  * display a header line followed by a load of volume lines
 586  */
 587 static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
 588 {
 589         struct afs_vlocation *vlocation =
 590                 list_entry(v, struct afs_vlocation, link);
 591
 592         /* display header on line 1 */
 593         if (v == (void *) 1) {
 594                 seq_puts(m, "USE VLID[0]  VLID[1]  VLID[2]  NAME\n");
 595                 return 0;
 596         }
 597
 598         /* display one cell per line on subsequent lines */
 599         seq_printf(m, "%3d %08x %08x %08x %s\n",
 600                    atomic_read(&vlocation->usage),
 601                    vlocation->vldb.vid[0],
 602                    vlocation->vldb.vid[1],
 603                    vlocation->vldb.vid[2],
 604                    vlocation->vldb.name
 605                    );
 606
 607         return 0;
 608 } /* end afs_proc_cell_volumes_show() */
 609
 610 /*****************************************************************************/
 611 /*
 612  * open "/proc/fs/afs/<cell>/vlservers" which provides a list of volume
 613  * location server
 614  */
 615 static int afs_proc_cell_vlservers_open(struct inode *inode, struct file *file)
 616 {
 617         struct afs_cell *cell;
 618         struct seq_file *m;
 619         int ret;
 620
 621         cell = afs_get_cell_maybe((struct afs_cell**)&PDE(inode)->data);
 622         if (!cell)
 623                 return -ENOENT;
 624
 625         ret = seq_open(file,&afs_proc_cell_vlservers_ops);
 626         if (ret<0)
 627                 return ret;
 628
 629         m = file->private_data;
 630         m->private = cell;
 631
 632         return 0;
 633 } /* end afs_proc_cell_vlservers_open() */
 634
 635 /*****************************************************************************/
 636 /*
 637  * close the file and release the ref to the cell
 638  */
 639 static int afs_proc_cell_vlservers_release(struct inode *inode,
 640                                            struct file *file)
 641 {
 642         struct afs_cell *cell = PDE(inode)->data;
 643         int ret;
 644
 645         ret = seq_release(inode,file);
 646
 647         afs_put_cell(cell);
 648
 649         return ret;
 650 } /* end afs_proc_cell_vlservers_release() */
 651
 652 /*****************************************************************************/
 653 /*
 654  * set up the iterator to start reading from the cells list and return the
 655  * first item
 656  */
 657 static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
 658 {
 659         struct afs_cell *cell = m->private;
 660         loff_t pos = *_pos;
 661
 662         _enter("cell=%p pos=%Ld", cell, *_pos);
 663
 664         /* lock the list against modification */
 665         down_read(&cell->vl_sem);
 666
 667         /* allow for the header line */
 668         if (!pos)
 669                 return (void *) 1;
 670         pos--;
 671
 672         if (pos >= cell->vl_naddrs)
 673                 return NULL;
 674
 675         return &cell->vl_addrs[pos];
 676 } /* end afs_proc_cell_vlservers_start() */
 677
 678 /*****************************************************************************/
 679 /*
 680  * move to next cell in cells list
 681  */
 682 static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
 683                                           loff_t *_pos)
 684 {
 685         struct afs_cell *cell = p->private;
 686         loff_t pos;
 687
 688         _enter("cell=%p{nad=%u} pos=%Ld", cell, cell->vl_naddrs, *_pos);
 689
 690         pos = *_pos;
 691         (*_pos)++;
 692         if (pos >= cell->vl_naddrs)
 693                 return NULL;
 694
 695         return &cell->vl_addrs[pos];
 696 } /* end afs_proc_cell_vlservers_next() */
 697
 698 /*****************************************************************************/
 699 /*
 700  * clean up after reading from the cells list
 701  */
 702 static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v)
 703 {
 704         struct afs_cell *cell = p->private;
 705
 706         up_read(&cell->vl_sem);
 707
 708 } /* end afs_proc_cell_vlservers_stop() */
 709
 710 /*****************************************************************************/
 711 /*
 712  * display a header line followed by a load of volume lines
 713  */
 714 static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
 715 {
 716         struct in_addr *addr = v;
 717
 718         /* display header on line 1 */
 719         if (v == (struct in_addr *) 1) {
 720                 seq_puts(m, "ADDRESS\n");
 721                 return 0;
 722         }
 723
 724         /* display one cell per line on subsequent lines */
 725         seq_printf(m, "%u.%u.%u.%u\n", NIPQUAD(addr->s_addr));
 726
 727         return 0;
 728 } /* end afs_proc_cell_vlservers_show() */
 729
 730 /*****************************************************************************/
 731 /*
 732  * open "/proc/fs/afs/<cell>/servers" which provides a summary of active
 733  * servers
 734  */
 735 static int afs_proc_cell_servers_open(struct inode *inode, struct file *file)
 736 {
 737         struct afs_cell *cell;
 738         struct seq_file *m;
 739         int ret;
 740
 741         cell = afs_get_cell_maybe((struct afs_cell **) &PDE(inode)->data);
 742         if (!cell)
 743                 return -ENOENT;
 744
 745         ret = seq_open(file, &afs_proc_cell_servers_ops);
 746         if (ret < 0)
 747                 return ret;
 748
 749         m = file->private_data;
 750         m->private = cell;
 751
 752         return 0;
 753 } /* end afs_proc_cell_servers_open() */
 754
 755 /*****************************************************************************/
 756 /*
 757  * close the file and release the ref to the cell
 758  */
 759 static int afs_proc_cell_servers_release(struct inode *inode,
 760                                          struct file *file)
 761 {
 762         struct afs_cell *cell = PDE(inode)->data;
 763         int ret;
 764
 765         ret = seq_release(inode, file);
 766
 767         afs_put_cell(cell);
 768
 769         return ret;
 770 } /* end afs_proc_cell_servers_release() */
 771
 772 /*****************************************************************************/
 773 /*
 774  * set up the iterator to start reading from the cells list and return the
 775  * first item
 776  */
 777 static void *afs_proc_cell_servers_start(struct seq_file *m, loff_t *_pos)
 778 {
 779         struct list_head *_p;
 780         struct afs_cell *cell = m->private;
 781         loff_t pos = *_pos;
 782
 783         _enter("cell=%p pos=%Ld", cell, *_pos);
 784
 785         /* lock the list against modification */
 786         read_lock(&cell->sv_lock);
 787
 788         /* allow for the header line */
 789         if (!pos)
 790                 return (void *) 1;
 791         pos--;
 792
 793         /* find the n'th element in the list */
 794         list_for_each(_p, &cell->sv_list)
 795                 if (!pos--)
 796                         break;
 797
 798         return _p != &cell->sv_list ? _p : NULL;
 799 } /* end afs_proc_cell_servers_start() */
 800
 801 /*****************************************************************************/
 802 /*
 803  * move to next cell in cells list
 804  */
 805 static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
 806                                         loff_t *_pos)
 807 {
 808         struct list_head *_p;
 809         struct afs_cell *cell = p->private;
 810
 811         _enter("cell=%p pos=%Ld", cell, *_pos);
 812
 813         (*_pos)++;
 814
 815         _p = v;
 816         _p = v == (void *) 1 ? cell->sv_list.next : _p->next;
 817
 818         return _p != &cell->sv_list ? _p : NULL;
 819 } /* end afs_proc_cell_servers_next() */
 820
 821 /*****************************************************************************/
 822 /*
 823  * clean up after reading from the cells list
 824  */
 825 static void afs_proc_cell_servers_stop(struct seq_file *p, void *v)
 826 {
 827         struct afs_cell *cell = p->private;
 828
 829         read_unlock(&cell->sv_lock);
 830
 831 } /* end afs_proc_cell_servers_stop() */
 832
 833 /*****************************************************************************/
 834 /*
 835  * display a header line followed by a load of volume lines
 836  */
 837 static int afs_proc_cell_servers_show(struct seq_file *m, void *v)
 838 {
 839         struct afs_server *server = list_entry(v, struct afs_server, link);
 840         char ipaddr[20];
 841
 842         /* display header on line 1 */
 843         if (v == (void *) 1) {
 844                 seq_puts(m, "USE ADDR            STATE\n");
 845                 return 0;
 846         }
 847
 848         /* display one cell per line on subsequent lines */
 849         sprintf(ipaddr, "%u.%u.%u.%u", NIPQUAD(server->addr));
 850         seq_printf(m, "%3d %-15.15s %5d\n",
 851                    atomic_read(&server->usage),
 852                    ipaddr,
 853                    server->fs_state
 854                    );
 855
 856         return 0;
 857 } /* end afs_proc_cell_servers_show() */