fs/jfs/super.c

   1 /*
   2  *   Copyright (C) International Business Machines Corp., 2000-2004
   3  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
   4  *
   5  *   This program is free software;  you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation; either version 2 of the License, or
   8  *   (at your option) any later version.
   9  *
  10  *   This program is distributed in the hope that it will be useful,
  11  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  13  *   the GNU General Public License for more details.
  14  *
  15  *   You should have received a copy of the GNU General Public License
  16  *   along with this program;  if not, write to the Free Software
  17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/module.h>
  22 #include <linux/parser.h>
  23 #include <linux/completion.h>
  24 #include <linux/vfs.h>
  25 #include <linux/quotaops.h>
  26 #include <linux/mount.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/kthread.h>
  29 #include <linux/posix_acl.h>
  30 #include <linux/buffer_head.h>
  31 #include <linux/exportfs.h>
  32 #include <linux/crc32.h>
  33 #include <linux/slab.h>
  34 #include <asm/uaccess.h>
  35 #include <linux/seq_file.h>
  36
  37 #include "jfs_incore.h"
  38 #include "jfs_filsys.h"
  39 #include "jfs_inode.h"
  40 #include "jfs_metapage.h"
  41 #include "jfs_superblock.h"
  42 #include "jfs_dmap.h"
  43 #include "jfs_imap.h"
  44 #include "jfs_acl.h"
  45 #include "jfs_debug.h"
  46
  47 MODULE_DESCRIPTION("The Journaled Filesystem (JFS)");
  48 MODULE_AUTHOR("Steve Best/Dave Kleikamp/Barry Arndt, IBM");
  49 MODULE_LICENSE("GPL");
  50
  51 static struct kmem_cache * jfs_inode_cachep;
  52
  53 static const struct super_operations jfs_super_operations;
  54 static const struct export_operations jfs_export_operations;
  55 static struct file_system_type jfs_fs_type;
  56
  57 #define MAX_COMMIT_THREADS 64
  58 static int commit_threads = 0;
  59 module_param(commit_threads, int, 0);
  60 MODULE_PARM_DESC(commit_threads, "Number of commit threads");
  61
  62 static struct task_struct *jfsCommitThread[MAX_COMMIT_THREADS];
  63 struct task_struct *jfsIOthread;
  64 struct task_struct *jfsSyncThread;
  65
  66 #ifdef CONFIG_JFS_DEBUG
  67 int jfsloglevel = JFS_LOGLEVEL_WARN;
  68 module_param(jfsloglevel, int, 0644);
  69 MODULE_PARM_DESC(jfsloglevel, "Specify JFS loglevel (0, 1 or 2)");
  70 #endif
  71
  72 static void jfs_handle_error(struct super_block *sb)
  73 {
  74         struct jfs_sb_info *sbi = JFS_SBI(sb);
  75
  76         if (sb->s_flags & MS_RDONLY)
  77                 return;
  78
  79         updateSuper(sb, FM_DIRTY);
  80
  81         if (sbi->flag & JFS_ERR_PANIC)
  82                 panic("JFS (device %s): panic forced after error\n",
  83                         sb->s_id);
  84         else if (sbi->flag & JFS_ERR_REMOUNT_RO) {
  85                 jfs_err("ERROR: (device %s): remounting filesystem "
  86                         "as read-only\n",
  87                         sb->s_id);
  88                 sb->s_flags |= MS_RDONLY;
  89         }
  90
  91         /* nothing is done for continue beyond marking the superblock dirty */
  92 }
  93
  94 void jfs_error(struct super_block *sb, const char * function, ...)
  95 {
  96         static char error_buf[256];
  97         va_list args;
  98
  99         va_start(args, function);
 100         vsnprintf(error_buf, sizeof(error_buf), function, args);
 101         va_end(args);
 102
 103         printk(KERN_ERR "ERROR: (device %s): %s\n", sb->s_id, error_buf);
 104
 105         jfs_handle_error(sb);
 106 }
 107
 108 static struct inode *jfs_alloc_inode(struct super_block *sb)
 109 {
 110         struct jfs_inode_info *jfs_inode;
 111
 112         jfs_inode = kmem_cache_alloc(jfs_inode_cachep, GFP_NOFS);
 113         if (!jfs_inode)
 114                 return NULL;
 115         return &jfs_inode->vfs_inode;
 116 }
 117
 118 static void jfs_destroy_inode(struct inode *inode)
 119 {
 120         struct jfs_inode_info *ji = JFS_IP(inode);
 121
 122         BUG_ON(!list_empty(&ji->anon_inode_list));
 123
 124         spin_lock_irq(&ji->ag_lock);
 125         if (ji->active_ag != -1) {
 126                 struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
 127                 atomic_dec(&bmap->db_active[ji->active_ag]);
 128                 ji->active_ag = -1;
 129         }
 130         spin_unlock_irq(&ji->ag_lock);
 131         kmem_cache_free(jfs_inode_cachep, ji);
 132 }
 133
 134 static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 135 {
 136         struct jfs_sb_info *sbi = JFS_SBI(dentry->d_sb);
 137         s64 maxinodes;
 138         struct inomap *imap = JFS_IP(sbi->ipimap)->i_imap;
 139
 140         jfs_info("In jfs_statfs");
 141         buf->f_type = JFS_SUPER_MAGIC;
 142         buf->f_bsize = sbi->bsize;
 143         buf->f_blocks = sbi->bmap->db_mapsize;
 144         buf->f_bfree = sbi->bmap->db_nfree;
 145         buf->f_bavail = sbi->bmap->db_nfree;
 146         /*
 147          * If we really return the number of allocated & free inodes, some
 148          * applications will fail because they won't see enough free inodes.
 149          * We'll try to calculate some guess as to how may inodes we can
 150          * really allocate
 151          *
 152          * buf->f_files = atomic_read(&imap->im_numinos);
 153          * buf->f_ffree = atomic_read(&imap->im_numfree);
 154          */
 155         maxinodes = min((s64) atomic_read(&imap->im_numinos) +
 156                         ((sbi->bmap->db_nfree >> imap->im_l2nbperiext)
 157                          << L2INOSPEREXT), (s64) 0xffffffffLL);
 158         buf->f_files = maxinodes;
 159         buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
 160                                     atomic_read(&imap->im_numfree));
 161         buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
 162         buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
 163                                         sizeof(sbi->uuid)/2);
 164
 165         buf->f_namelen = JFS_NAME_MAX;
 166         return 0;
 167 }
 168
 169 static void jfs_put_super(struct super_block *sb)
 170 {
 171         struct jfs_sb_info *sbi = JFS_SBI(sb);
 172         int rc;
 173
 174         jfs_info("In jfs_put_super");
 175
 176         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
 177
 178         rc = jfs_umount(sb);
 179         if (rc)
 180                 jfs_err("jfs_umount failed with return code %d", rc);
 181
 182         unload_nls(sbi->nls_tab);
 183
 184         truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
 185         iput(sbi->direct_inode);
 186
 187         kfree(sbi);
 188 }
 189
 190 enum {
 191         Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
 192         Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
 193         Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
 194 };
 195
 196 static const match_table_t tokens = {
 197         {Opt_integrity, "integrity"},
 198         {Opt_nointegrity, "nointegrity"},
 199         {Opt_iocharset, "iocharset=%s"},
 200         {Opt_resize, "resize=%u"},
 201         {Opt_resize_nosize, "resize"},
 202         {Opt_errors, "errors=%s"},
 203         {Opt_ignore, "noquota"},
 204         {Opt_ignore, "quota"},
 205         {Opt_usrquota, "usrquota"},
 206         {Opt_grpquota, "grpquota"},
 207         {Opt_uid, "uid=%u"},
 208         {Opt_gid, "gid=%u"},
 209         {Opt_umask, "umask=%u"},
 210         {Opt_err, NULL}
 211 };
 212
 213 static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
 214                          int *flag)
 215 {
 216         void *nls_map = (void *)-1;     /* -1: no change;  NULL: none */
 217         char *p;
 218         struct jfs_sb_info *sbi = JFS_SBI(sb);
 219
 220         *newLVSize = 0;
 221
 222         if (!options)
 223                 return 1;
 224
 225         while ((p = strsep(&options, ",")) != NULL) {
 226                 substring_t args[MAX_OPT_ARGS];
 227                 int token;
 228                 if (!*p)
 229                         continue;
 230
 231                 token = match_token(p, tokens, args);
 232                 switch (token) {
 233                 case Opt_integrity:
 234                         *flag &= ~JFS_NOINTEGRITY;
 235                         break;
 236                 case Opt_nointegrity:
 237                         *flag |= JFS_NOINTEGRITY;
 238                         break;
 239                 case Opt_ignore:
 240                         /* Silently ignore the quota options */
 241                         /* Don't do anything ;-) */
 242                         break;
 243                 case Opt_iocharset:
 244                         if (nls_map && nls_map != (void *) -1)
 245                                 unload_nls(nls_map);
 246                         if (!strcmp(args[0].from, "none"))
 247                                 nls_map = NULL;
 248                         else {
 249                                 nls_map = load_nls(args[0].from);
 250                                 if (!nls_map) {
 251                                         printk(KERN_ERR
 252                                                "JFS: charset not found\n");
 253                                         goto cleanup;
 254                                 }
 255                         }
 256                         break;
 257                 case Opt_resize:
 258                 {
 259                         char *resize = args[0].from;
 260                         *newLVSize = simple_strtoull(resize, &resize, 0);
 261                         break;
 262                 }
 263                 case Opt_resize_nosize:
 264                 {
 265                         *newLVSize = sb->s_bdev->bd_inode->i_size >>
 266                                 sb->s_blocksize_bits;
 267                         if (*newLVSize == 0)
 268                                 printk(KERN_ERR
 269                                        "JFS: Cannot determine volume size\n");
 270                         break;
 271                 }
 272                 case Opt_errors:
 273                 {
 274                         char *errors = args[0].from;
 275                         if (!errors || !*errors)
 276                                 goto cleanup;
 277                         if (!strcmp(errors, "continue")) {
 278                                 *flag &= ~JFS_ERR_REMOUNT_RO;
 279                                 *flag &= ~JFS_ERR_PANIC;
 280                                 *flag |= JFS_ERR_CONTINUE;
 281                         } else if (!strcmp(errors, "remount-ro")) {
 282                                 *flag &= ~JFS_ERR_CONTINUE;
 283                                 *flag &= ~JFS_ERR_PANIC;
 284                                 *flag |= JFS_ERR_REMOUNT_RO;
 285                         } else if (!strcmp(errors, "panic")) {
 286                                 *flag &= ~JFS_ERR_CONTINUE;
 287                                 *flag &= ~JFS_ERR_REMOUNT_RO;
 288                                 *flag |= JFS_ERR_PANIC;
 289                         } else {
 290                                 printk(KERN_ERR
 291                                        "JFS: %s is an invalid error handler\n",
 292                                        errors);
 293                                 goto cleanup;
 294                         }
 295                         break;
 296                 }
 297
 298 #ifdef CONFIG_QUOTA
 299                 case Opt_quota:
 300                 case Opt_usrquota:
 301                         *flag |= JFS_USRQUOTA;
 302                         break;
 303                 case Opt_grpquota:
 304                         *flag |= JFS_GRPQUOTA;
 305                         break;
 306 #else
 307                 case Opt_usrquota:
 308                 case Opt_grpquota:
 309                 case Opt_quota:
 310                         printk(KERN_ERR
 311                                "JFS: quota operations not supported\n");
 312                         break;
 313 #endif
 314                 case Opt_uid:
 315                 {
 316                         char *uid = args[0].from;
 317                         sbi->uid = simple_strtoul(uid, &uid, 0);
 318                         break;
 319                 }
 320                 case Opt_gid:
 321                 {
 322                         char *gid = args[0].from;
 323                         sbi->gid = simple_strtoul(gid, &gid, 0);
 324                         break;
 325                 }
 326                 case Opt_umask:
 327                 {
 328                         char *umask = args[0].from;
 329                         sbi->umask = simple_strtoul(umask, &umask, 8);
 330                         if (sbi->umask & ~0777) {
 331                                 printk(KERN_ERR
 332                                        "JFS: Invalid value of umask\n");
 333                                 goto cleanup;
 334                         }
 335                         break;
 336                 }
 337                 default:
 338                         printk("jfs: Unrecognized mount option \"%s\" "
 339                                         " or missing value\n", p);
 340                         goto cleanup;
 341                 }
 342         }
 343
 344         if (nls_map != (void *) -1) {
 345                 /* Discard old (if remount) */
 346                 unload_nls(sbi->nls_tab);
 347                 sbi->nls_tab = nls_map;
 348         }
 349         return 1;
 350
 351 cleanup:
 352         if (nls_map && nls_map != (void *) -1)
 353                 unload_nls(nls_map);
 354         return 0;
 355 }
 356
 357 static int jfs_remount(struct super_block *sb, int *flags, char *data)
 358 {
 359         s64 newLVSize = 0;
 360         int rc = 0;
 361         int flag = JFS_SBI(sb)->flag;
 362         int ret;
 363
 364         if (!parse_options(data, sb, &newLVSize, &flag)) {
 365                 return -EINVAL;
 366         }
 367
 368         if (newLVSize) {
 369                 if (sb->s_flags & MS_RDONLY) {
 370                         printk(KERN_ERR
 371                   "JFS: resize requires volume to be mounted read-write\n");
 372                         return -EROFS;
 373                 }
 374                 rc = jfs_extendfs(sb, newLVSize, 0);
 375                 if (rc)
 376                         return rc;
 377         }
 378
 379         if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
 380                 /*
 381                  * Invalidate any previously read metadata.  fsck may have
 382                  * changed the on-disk data since we mounted r/o
 383                  */
 384                 truncate_inode_pages(JFS_SBI(sb)->direct_inode->i_mapping, 0);
 385
 386                 JFS_SBI(sb)->flag = flag;
 387                 ret = jfs_mount_rw(sb, 1);
 388
 389                 /* mark the fs r/w for quota activity */
 390                 sb->s_flags &= ~MS_RDONLY;
 391
 392                 dquot_resume(sb, -1);
 393                 return ret;
 394         }
 395         if ((!(sb->s_flags & MS_RDONLY)) && (*flags & MS_RDONLY)) {
 396                 rc = dquot_suspend(sb, -1);
 397                 if (rc < 0) {
 398                         return rc;
 399                 }
 400                 rc = jfs_umount_rw(sb);
 401                 JFS_SBI(sb)->flag = flag;
 402                 return rc;
 403         }
 404         if ((JFS_SBI(sb)->flag & JFS_NOINTEGRITY) != (flag & JFS_NOINTEGRITY))
 405                 if (!(sb->s_flags & MS_RDONLY)) {
 406                         rc = jfs_umount_rw(sb);
 407                         if (rc)
 408                                 return rc;
 409
 410                         JFS_SBI(sb)->flag = flag;
 411                         ret = jfs_mount_rw(sb, 1);
 412                         return ret;
 413                 }
 414         JFS_SBI(sb)->flag = flag;
 415
 416         return 0;
 417 }
 418
 419 static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 420 {
 421         struct jfs_sb_info *sbi;
 422         struct inode *inode;
 423         int rc;
 424         s64 newLVSize = 0;
 425         int flag, ret = -EINVAL;
 426
 427         jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);
 428
 429         if (!new_valid_dev(sb->s_bdev->bd_dev))
 430                 return -EOVERFLOW;
 431
 432         sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);
 433         if (!sbi)
 434                 return -ENOMEM;
 435
 436         sb->s_fs_info = sbi;
 437         sbi->sb = sb;
 438         sbi->uid = sbi->gid = sbi->umask = -1;
 439
 440         /* initialize the mount flag and determine the default error handler */
 441         flag = JFS_ERR_REMOUNT_RO;
 442
 443         if (!parse_options((char *) data, sb, &newLVSize, &flag))
 444                 goto out_kfree;
 445         sbi->flag = flag;
 446
 447 #ifdef CONFIG_JFS_POSIX_ACL
 448         sb->s_flags |= MS_POSIXACL;
 449 #endif
 450
 451         if (newLVSize) {
 452                 printk(KERN_ERR "resize option for remount only\n");
 453                 goto out_kfree;
 454         }
 455
 456         /*
 457          * Initialize blocksize to 4K.
 458          */
 459         sb_set_blocksize(sb, PSIZE);
 460
 461         /*
 462          * Set method vectors.
 463          */
 464         sb->s_op = &jfs_super_operations;
 465         sb->s_export_op = &jfs_export_operations;
 466 #ifdef CONFIG_QUOTA
 467         sb->dq_op = &dquot_operations;
 468         sb->s_qcop = &dquot_quotactl_ops;
 469 #endif
 470
 471         /*
 472          * Initialize direct-mapping inode/address-space
 473          */
 474         inode = new_inode(sb);
 475         if (inode == NULL) {
 476                 ret = -ENOMEM;
 477                 goto out_unload;
 478         }
 479         inode->i_ino = 0;
 480         inode->i_nlink = 1;
 481         inode->i_size = sb->s_bdev->bd_inode->i_size;
 482         inode->i_mapping->a_ops = &jfs_metapage_aops;
 483         insert_inode_hash(inode);
 484         mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
 485
 486         sbi->direct_inode = inode;
 487
 488         rc = jfs_mount(sb);
 489         if (rc) {
 490                 if (!silent) {
 491                         jfs_err("jfs_mount failed w/return code = %d", rc);
 492                 }
 493                 goto out_mount_failed;
 494         }
 495         if (sb->s_flags & MS_RDONLY)
 496                 sbi->log = NULL;
 497         else {
 498                 rc = jfs_mount_rw(sb, 0);
 499                 if (rc) {
 500                         if (!silent) {
 501                                 jfs_err("jfs_mount_rw failed, return code = %d",
 502                                         rc);
 503                         }
 504                         goto out_no_rw;
 505                 }
 506         }
 507
 508         sb->s_magic = JFS_SUPER_MAGIC;
 509
 510         inode = jfs_iget(sb, ROOT_I);
 511         if (IS_ERR(inode)) {
 512                 ret = PTR_ERR(inode);
 513                 goto out_no_rw;
 514         }
 515         sb->s_root = d_alloc_root(inode);
 516         if (!sb->s_root)
 517                 goto out_no_root;
 518
 519         if (sbi->mntflag & JFS_OS2)
 520                 sb->s_root->d_op = &jfs_ci_dentry_operations;
 521
 522         /* logical blocks are represented by 40 bits in pxd_t, etc. */
 523         sb->s_maxbytes = ((u64) sb->s_blocksize) << 40;
 524 #if BITS_PER_LONG == 32
 525         /*
 526          * Page cache is indexed by long.
 527          * I would use MAX_LFS_FILESIZE, but it's only half as big
 528          */
 529         sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, (u64)sb->s_maxbytes);
 530 #endif
 531         sb->s_time_gran = 1;
 532         return 0;
 533
 534 out_no_root:
 535         jfs_err("jfs_read_super: get root dentry failed");
 536         iput(inode);
 537
 538 out_no_rw:
 539         rc = jfs_umount(sb);
 540         if (rc) {
 541                 jfs_err("jfs_umount failed with return code %d", rc);
 542         }
 543 out_mount_failed:
 544         filemap_write_and_wait(sbi->direct_inode->i_mapping);
 545         truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
 546         make_bad_inode(sbi->direct_inode);
 547         iput(sbi->direct_inode);
 548         sbi->direct_inode = NULL;
 549 out_unload:
 550         if (sbi->nls_tab)
 551                 unload_nls(sbi->nls_tab);
 552 out_kfree:
 553         kfree(sbi);
 554         return ret;
 555 }
 556
 557 static int jfs_freeze(struct super_block *sb)
 558 {
 559         struct jfs_sb_info *sbi = JFS_SBI(sb);
 560         struct jfs_log *log = sbi->log;
 561
 562         if (!(sb->s_flags & MS_RDONLY)) {
 563                 txQuiesce(sb);
 564                 lmLogShutdown(log);
 565                 updateSuper(sb, FM_CLEAN);
 566         }
 567         return 0;
 568 }
 569
 570 static int jfs_unfreeze(struct super_block *sb)
 571 {
 572         struct jfs_sb_info *sbi = JFS_SBI(sb);
 573         struct jfs_log *log = sbi->log;
 574         int rc = 0;
 575
 576         if (!(sb->s_flags & MS_RDONLY)) {
 577                 updateSuper(sb, FM_MOUNT);
 578                 if ((rc = lmLogInit(log)))
 579                         jfs_err("jfs_unlock failed with return code %d", rc);
 580                 else
 581                         txResume(sb);
 582         }
 583         return 0;
 584 }
 585
 586 static int jfs_get_sb(struct file_system_type *fs_type,
 587         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 588 {
 589         return get_sb_bdev(fs_type, flags, dev_name, data, jfs_fill_super,
 590                            mnt);
 591 }
 592
 593 static int jfs_sync_fs(struct super_block *sb, int wait)
 594 {
 595         struct jfs_log *log = JFS_SBI(sb)->log;
 596
 597         /* log == NULL indicates read-only mount */
 598         if (log) {
 599                 jfs_flush_journal(log, wait);
 600                 jfs_syncpt(log, 0);
 601         }
 602
 603         return 0;
 604 }
 605
 606 static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 607 {
 608         struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);
 609
 610         if (sbi->uid != -1)
 611                 seq_printf(seq, ",uid=%d", sbi->uid);
 612         if (sbi->gid != -1)
 613                 seq_printf(seq, ",gid=%d", sbi->gid);
 614         if (sbi->umask != -1)
 615                 seq_printf(seq, ",umask=%03o", sbi->umask);
 616         if (sbi->flag & JFS_NOINTEGRITY)
 617                 seq_puts(seq, ",nointegrity");
 618         if (sbi->nls_tab)
 619                 seq_printf(seq, ",iocharset=%s", sbi->nls_tab->charset);
 620         if (sbi->flag & JFS_ERR_CONTINUE)
 621                 seq_printf(seq, ",errors=continue");
 622         if (sbi->flag & JFS_ERR_PANIC)
 623                 seq_printf(seq, ",errors=panic");
 624
 625 #ifdef CONFIG_QUOTA
 626         if (sbi->flag & JFS_USRQUOTA)
 627                 seq_puts(seq, ",usrquota");
 628
 629         if (sbi->flag & JFS_GRPQUOTA)
 630                 seq_puts(seq, ",grpquota");
 631 #endif
 632
 633         return 0;
 634 }
 635
 636 #ifdef CONFIG_QUOTA
 637
 638 /* Read data from quotafile - avoid pagecache and such because we cannot afford
 639  * acquiring the locks... As quota files are never truncated and quota code
 640  * itself serializes the operations (and noone else should touch the files)
 641  * we don't have to be afraid of races */
 642 static ssize_t jfs_quota_read(struct super_block *sb, int type, char *data,
 643                               size_t len, loff_t off)
 644 {
 645         struct inode *inode = sb_dqopt(sb)->files[type];
 646         sector_t blk = off >> sb->s_blocksize_bits;
 647         int err = 0;
 648         int offset = off & (sb->s_blocksize - 1);
 649         int tocopy;
 650         size_t toread;
 651         struct buffer_head tmp_bh;
 652         struct buffer_head *bh;
 653         loff_t i_size = i_size_read(inode);
 654
 655         if (off > i_size)
 656                 return 0;
 657         if (off+len > i_size)
 658                 len = i_size-off;
 659         toread = len;
 660         while (toread > 0) {
 661                 tocopy = sb->s_blocksize - offset < toread ?
 662                                 sb->s_blocksize - offset : toread;
 663
 664                 tmp_bh.b_state = 0;
 665                 tmp_bh.b_size = 1 << inode->i_blkbits;
 666                 err = jfs_get_block(inode, blk, &tmp_bh, 0);
 667                 if (err)
 668                         return err;
 669                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
 670                         memset(data, 0, tocopy);
 671                 else {
 672                         bh = sb_bread(sb, tmp_bh.b_blocknr);
 673                         if (!bh)
 674                                 return -EIO;
 675                         memcpy(data, bh->b_data+offset, tocopy);
 676                         brelse(bh);
 677                 }
 678                 offset = 0;
 679                 toread -= tocopy;
 680                 data += tocopy;
 681                 blk++;
 682         }
 683         return len;
 684 }
 685
 686 /* Write to quotafile */
 687 static ssize_t jfs_quota_write(struct super_block *sb, int type,
 688                                const char *data, size_t len, loff_t off)
 689 {
 690         struct inode *inode = sb_dqopt(sb)->files[type];
 691         sector_t blk = off >> sb->s_blocksize_bits;
 692         int err = 0;
 693         int offset = off & (sb->s_blocksize - 1);
 694         int tocopy;
 695         size_t towrite = len;
 696         struct buffer_head tmp_bh;
 697         struct buffer_head *bh;
 698
 699         mutex_lock(&inode->i_mutex);
 700         while (towrite > 0) {
 701                 tocopy = sb->s_blocksize - offset < towrite ?
 702                                 sb->s_blocksize - offset : towrite;
 703
 704                 tmp_bh.b_state = 0;
 705                 tmp_bh.b_size = 1 << inode->i_blkbits;
 706                 err = jfs_get_block(inode, blk, &tmp_bh, 1);
 707                 if (err)
 708                         goto out;
 709                 if (offset || tocopy != sb->s_blocksize)
 710                         bh = sb_bread(sb, tmp_bh.b_blocknr);
 711                 else
 712                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
 713                 if (!bh) {
 714                         err = -EIO;
 715                         goto out;
 716                 }
 717                 lock_buffer(bh);
 718                 memcpy(bh->b_data+offset, data, tocopy);
 719                 flush_dcache_page(bh->b_page);
 720                 set_buffer_uptodate(bh);
 721                 mark_buffer_dirty(bh);
 722                 unlock_buffer(bh);
 723                 brelse(bh);
 724                 offset = 0;
 725                 towrite -= tocopy;
 726                 data += tocopy;
 727                 blk++;
 728         }
 729 out:
 730         if (len == towrite) {
 731                 mutex_unlock(&inode->i_mutex);
 732                 return err;
 733         }
 734         if (inode->i_size < off+len-towrite)
 735                 i_size_write(inode, off+len-towrite);
 736         inode->i_version++;
 737         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 738         mark_inode_dirty(inode);
 739         mutex_unlock(&inode->i_mutex);
 740         return len - towrite;
 741 }
 742
 743 #endif
 744
 745 static const struct super_operations jfs_super_operations = {
 746         .alloc_inode    = jfs_alloc_inode,
 747         .destroy_inode  = jfs_destroy_inode,
 748         .dirty_inode    = jfs_dirty_inode,
 749         .write_inode    = jfs_write_inode,
 750         .evict_inode    = jfs_evict_inode,
 751         .put_super      = jfs_put_super,
 752         .sync_fs        = jfs_sync_fs,
 753         .freeze_fs      = jfs_freeze,
 754         .unfreeze_fs    = jfs_unfreeze,
 755         .statfs         = jfs_statfs,
 756         .remount_fs     = jfs_remount,
 757         .show_options   = jfs_show_options,
 758 #ifdef CONFIG_QUOTA
 759         .quota_read     = jfs_quota_read,
 760         .quota_write    = jfs_quota_write,
 761 #endif
 762 };
 763
 764 static const struct export_operations jfs_export_operations = {
 765         .fh_to_dentry   = jfs_fh_to_dentry,
 766         .fh_to_parent   = jfs_fh_to_parent,
 767         .get_parent     = jfs_get_parent,
 768 };
 769
 770 static struct file_system_type jfs_fs_type = {
 771         .owner          = THIS_MODULE,
 772         .name           = "jfs",
 773         .get_sb         = jfs_get_sb,
 774         .kill_sb        = kill_block_super,
 775         .fs_flags       = FS_REQUIRES_DEV,
 776 };
 777
 778 static void init_once(void *foo)
 779 {
 780         struct jfs_inode_info *jfs_ip = (struct jfs_inode_info *) foo;
 781
 782         memset(jfs_ip, 0, sizeof(struct jfs_inode_info));
 783         INIT_LIST_HEAD(&jfs_ip->anon_inode_list);
 784         init_rwsem(&jfs_ip->rdwrlock);
 785         mutex_init(&jfs_ip->commit_mutex);
 786         init_rwsem(&jfs_ip->xattr_sem);
 787         spin_lock_init(&jfs_ip->ag_lock);
 788         jfs_ip->active_ag = -1;
 789         inode_init_once(&jfs_ip->vfs_inode);
 790 }
 791
 792 static int __init init_jfs_fs(void)
 793 {
 794         int i;
 795         int rc;
 796
 797         jfs_inode_cachep =
 798             kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0,
 799                             SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
 800                             init_once);
 801         if (jfs_inode_cachep == NULL)
 802                 return -ENOMEM;
 803
 804         /*
 805          * Metapage initialization
 806          */
 807         rc = metapage_init();
 808         if (rc) {
 809                 jfs_err("metapage_init failed w/rc = %d", rc);
 810                 goto free_slab;
 811         }
 812
 813         /*
 814          * Transaction Manager initialization
 815          */
 816         rc = txInit();
 817         if (rc) {
 818                 jfs_err("txInit failed w/rc = %d", rc);
 819                 goto free_metapage;
 820         }
 821
 822         /*
 823          * I/O completion thread (endio)
 824          */
 825         jfsIOthread = kthread_run(jfsIOWait, NULL, "jfsIO");
 826         if (IS_ERR(jfsIOthread)) {
 827                 rc = PTR_ERR(jfsIOthread);
 828                 jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
 829                 goto end_txmngr;
 830         }
 831
 832         if (commit_threads < 1)
 833                 commit_threads = num_online_cpus();
 834         if (commit_threads > MAX_COMMIT_THREADS)
 835                 commit_threads = MAX_COMMIT_THREADS;
 836
 837         for (i = 0; i < commit_threads; i++) {
 838                 jfsCommitThread[i] = kthread_run(jfs_lazycommit, NULL, "jfsCommit");
 839                 if (IS_ERR(jfsCommitThread[i])) {
 840                         rc = PTR_ERR(jfsCommitThread[i]);
 841                         jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
 842                         commit_threads = i;
 843                         goto kill_committask;
 844                 }
 845         }
 846
 847         jfsSyncThread = kthread_run(jfs_sync, NULL, "jfsSync");
 848         if (IS_ERR(jfsSyncThread)) {
 849                 rc = PTR_ERR(jfsSyncThread);
 850                 jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
 851                 goto kill_committask;
 852         }
 853
 854 #ifdef PROC_FS_JFS
 855         jfs_proc_init();
 856 #endif
 857
 858         return register_filesystem(&jfs_fs_type);
 859
 860 kill_committask:
 861         for (i = 0; i < commit_threads; i++)
 862                 kthread_stop(jfsCommitThread[i]);
 863         kthread_stop(jfsIOthread);
 864 end_txmngr:
 865         txExit();
 866 free_metapage:
 867         metapage_exit();
 868 free_slab:
 869         kmem_cache_destroy(jfs_inode_cachep);
 870         return rc;
 871 }
 872
 873 static void __exit exit_jfs_fs(void)
 874 {
 875         int i;
 876
 877         jfs_info("exit_jfs_fs called");
 878
 879         txExit();
 880         metapage_exit();
 881
 882         kthread_stop(jfsIOthread);
 883         for (i = 0; i < commit_threads; i++)
 884                 kthread_stop(jfsCommitThread[i]);
 885         kthread_stop(jfsSyncThread);
 886 #ifdef PROC_FS_JFS
 887         jfs_proc_clean();
 888 #endif
 889         unregister_filesystem(&jfs_fs_type);
 890         kmem_cache_destroy(jfs_inode_cachep);
 891 }
 892
 893 module_init(init_jfs_fs)
 894 module_exit(exit_jfs_fs)