fs/coda/dir.c

   1
   2 /*
   3  * Directory operations for Coda filesystem
   4  * Original version: (C) 1996 P. Braam and M. Callahan
   5  * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
   6  *
   7  * Carnegie Mellon encourages users to contribute improvements to
   8  * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/time.h>
  14 #include <linux/fs.h>
  15 #include <linux/file.h>
  16 #include <linux/stat.h>
  17 #include <linux/errno.h>
  18 #include <linux/string.h>
  19 #include <linux/smp_lock.h>
  20
  21 #include <asm/uaccess.h>
  22
  23 #include <linux/coda.h>
  24 #include <linux/coda_linux.h>
  25 #include <linux/coda_psdev.h>
  26 #include <linux/coda_fs_i.h>
  27 #include <linux/coda_cache.h>
  28 #include <linux/coda_proc.h>
  29
  30 #include "coda_int.h"
  31
  32 /* dir inode-ops */
  33 static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
  34 static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
  35 static int coda_link(struct dentry *old_dentry, struct inode *dir_inode,
  36                      struct dentry *entry);
  37 static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
  38 static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
  39                         const char *symname);
  40 static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
  41 static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
  42 static int coda_rename(struct inode *old_inode, struct dentry *old_dentry,
  43                        struct inode *new_inode, struct dentry *new_dentry);
  44
  45 /* dir file-ops */
  46 static int coda_readdir(struct file *file, void *dirent, filldir_t filldir);
  47
  48 /* dentry ops */
  49 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
  50 static int coda_dentry_delete(struct dentry *);
  51
  52 /* support routines */
  53 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
  54                               void *dirent, struct dentry *dir);
  55
  56 /* same as fs/bad_inode.c */
  57 static int coda_return_EIO(void)
  58 {
  59         return -EIO;
  60 }
  61 #define CODA_EIO_ERROR ((void *) (coda_return_EIO))
  62
  63 static struct dentry_operations coda_dentry_operations =
  64 {
  65         .d_revalidate   = coda_dentry_revalidate,
  66         .d_delete       = coda_dentry_delete,
  67 };
  68
  69 struct inode_operations coda_dir_inode_operations =
  70 {
  71         .create         = coda_create,
  72         .lookup         = coda_lookup,
  73         .link           = coda_link,
  74         .unlink         = coda_unlink,
  75         .symlink        = coda_symlink,
  76         .mkdir          = coda_mkdir,
  77         .rmdir          = coda_rmdir,
  78         .mknod          = CODA_EIO_ERROR,
  79         .rename         = coda_rename,
  80         .permission     = coda_permission,
  81         .getattr        = coda_getattr,
  82         .setattr        = coda_setattr,
  83 };
  84
  85 struct file_operations coda_dir_operations = {
  86         .llseek         = generic_file_llseek,
  87         .read           = generic_read_dir,
  88         .readdir        = coda_readdir,
  89         .open           = coda_open,
  90         .flush          = coda_flush,
  91         .release        = coda_release,
  92         .fsync          = coda_fsync,
  93 };
  94
  95
  96 /* inode operations for directories */
  97 /* access routines: lookup, readlink, permission */
  98 static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
  99 {
 100         struct inode *res_inode = NULL;
 101         struct CodaFid resfid = { { 0, } };
 102         int dropme = 0; /* to indicate entry should not be cached */
 103         int type = 0;
 104         int error = 0;
 105         const char *name = entry->d_name.name;
 106         size_t length = entry->d_name.len;
 107
 108         if ( length > CODA_MAXNAMLEN ) {
 109                 printk("name too long: lookup, %s (%*s)\n",
 110                        coda_i2s(dir), (int)length, name);
 111                 return ERR_PTR(-ENAMETOOLONG);
 112         }
 113
 114         lock_kernel();
 115         /* control object, create inode on the fly */
 116         if (coda_isroot(dir) && coda_iscontrol(name, length)) {
 117                 error = coda_cnode_makectl(&res_inode, dir->i_sb);
 118                 dropme = 1;
 119                 goto exit;
 120         }
 121
 122         error = venus_lookup(dir->i_sb, coda_i2f(dir),
 123                              (const char *)name, length, &type, &resfid);
 124
 125         res_inode = NULL;
 126         if (!error) {
 127                 if (type & CODA_NOCACHE) {
 128                         type &= (~CODA_NOCACHE);
 129                         dropme = 1;
 130                 }
 131
 132                 error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
 133                 if (error) {
 134                         unlock_kernel();
 135                         return ERR_PTR(error);
 136                 }
 137         } else if (error != -ENOENT) {
 138                 unlock_kernel();
 139                 return ERR_PTR(error);
 140         }
 141
 142 exit:
 143         entry->d_time = 0;
 144         entry->d_op = &coda_dentry_operations;
 145         d_add(entry, res_inode);
 146         if ( dropme ) {
 147                 d_drop(entry);
 148                 coda_flag_inode(res_inode, C_VATTR);
 149         }
 150         unlock_kernel();
 151         return NULL;
 152 }
 153
 154
 155 int coda_permission(struct inode *inode, int mask, struct nameidata *nd)
 156 {
 157         int error = 0;
 158
 159         if (!mask)
 160                 return 0;
 161
 162         lock_kernel();
 163
 164         coda_vfs_stat.permission++;
 165
 166         if (coda_cache_check(inode, mask))
 167                 goto out;
 168
 169         error = venus_access(inode->i_sb, coda_i2f(inode), mask);
 170
 171         if (!error)
 172                 coda_cache_enter(inode, mask);
 173
 174  out:
 175         unlock_kernel();
 176
 177         return error;
 178 }
 179
 180
 181 static inline void coda_dir_changed(struct inode *dir, int link)
 182 {
 183 #ifdef REQUERY_VENUS_FOR_MTIME
 184         /* invalidate the directory cnode's attributes so we refetch the
 185          * attributes from venus next time the inode is referenced */
 186         coda_flag_inode(dir, C_VATTR);
 187 #else
 188         /* optimistically we can also act as if our nose bleeds. The
 189          * granularity of the mtime is coarse anyways so we might actually be
 190          * right most of the time. Note: we only do this for directories. */
 191         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
 192 #endif
 193         if (link)
 194                 dir->i_nlink += link;
 195 }
 196
 197 /* creation routines: create, mknod, mkdir, link, symlink */
 198 static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
 199 {
 200         int error=0;
 201         const char *name=de->d_name.name;
 202         int length=de->d_name.len;
 203         struct inode *inode;
 204         struct CodaFid newfid;
 205         struct coda_vattr attrs;
 206
 207         lock_kernel();
 208         coda_vfs_stat.create++;
 209
 210         if (coda_isroot(dir) && coda_iscontrol(name, length)) {
 211                 unlock_kernel();
 212                 return -EPERM;
 213         }
 214
 215         error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
 216                                 0, mode, &newfid, &attrs);
 217
 218         if ( error ) {
 219                 unlock_kernel();
 220                 d_drop(de);
 221                 return error;
 222         }
 223
 224         inode = coda_iget(dir->i_sb, &newfid, &attrs);
 225         if ( IS_ERR(inode) ) {
 226                 unlock_kernel();
 227                 d_drop(de);
 228                 return PTR_ERR(inode);
 229         }
 230
 231         /* invalidate the directory cnode's attributes */
 232         coda_dir_changed(dir, 0);
 233         unlock_kernel();
 234         d_instantiate(de, inode);
 235         return 0;
 236 }
 237
 238 static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
 239 {
 240         struct inode *inode;
 241         struct coda_vattr attrs;
 242         const char *name = de->d_name.name;
 243         int len = de->d_name.len;
 244         int error;
 245         struct CodaFid newfid;
 246
 247         lock_kernel();
 248         coda_vfs_stat.mkdir++;
 249
 250         if (coda_isroot(dir) && coda_iscontrol(name, len)) {
 251                 unlock_kernel();
 252                 return -EPERM;
 253         }
 254
 255         attrs.va_mode = mode;
 256         error = venus_mkdir(dir->i_sb, coda_i2f(dir),
 257                                name, len, &newfid, &attrs);
 258
 259         if ( error ) {
 260                 unlock_kernel();
 261                 d_drop(de);
 262                 return error;
 263         }
 264
 265         inode = coda_iget(dir->i_sb, &newfid, &attrs);
 266         if ( IS_ERR(inode) ) {
 267                 unlock_kernel();
 268                 d_drop(de);
 269                 return PTR_ERR(inode);
 270         }
 271
 272         /* invalidate the directory cnode's attributes */
 273         coda_dir_changed(dir, 1);
 274         unlock_kernel();
 275         d_instantiate(de, inode);
 276         return 0;
 277 }
 278
 279 /* try to make de an entry in dir_inodde linked to source_de */
 280 static int coda_link(struct dentry *source_de, struct inode *dir_inode,
 281           struct dentry *de)
 282 {
 283         struct inode *inode = source_de->d_inode;
 284         const char * name = de->d_name.name;
 285         int len = de->d_name.len;
 286         int error;
 287
 288         lock_kernel();
 289         coda_vfs_stat.link++;
 290
 291         if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
 292                 unlock_kernel();
 293                 return -EPERM;
 294         }
 295
 296         error = venus_link(dir_inode->i_sb, coda_i2f(inode),
 297                            coda_i2f(dir_inode), (const char *)name, len);
 298
 299         if (error) {
 300                 d_drop(de);
 301                 goto out;
 302         }
 303
 304         coda_dir_changed(dir_inode, 0);
 305         atomic_inc(&inode->i_count);
 306         d_instantiate(de, inode);
 307         inode->i_nlink++;
 308
 309 out:
 310         unlock_kernel();
 311         return(error);
 312 }
 313
 314
 315 static int coda_symlink(struct inode *dir_inode, struct dentry *de,
 316                         const char *symname)
 317 {
 318         const char *name = de->d_name.name;
 319         int len = de->d_name.len;
 320         int symlen;
 321         int error=0;
 322
 323         lock_kernel();
 324         coda_vfs_stat.symlink++;
 325
 326         if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
 327                 unlock_kernel();
 328                 return -EPERM;
 329         }
 330
 331         symlen = strlen(symname);
 332         if ( symlen > CODA_MAXPATHLEN ) {
 333                 unlock_kernel();
 334                 return -ENAMETOOLONG;
 335         }
 336
 337         /*
 338          * This entry is now negative. Since we do not create
 339          * an inode for the entry we have to drop it.
 340          */
 341         d_drop(de);
 342         error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
 343                               symname, symlen);
 344
 345         /* mtime is no good anymore */
 346         if ( !error )
 347                 coda_dir_changed(dir_inode, 0);
 348
 349         unlock_kernel();
 350         return error;
 351 }
 352
 353 /* destruction routines: unlink, rmdir */
 354 int coda_unlink(struct inode *dir, struct dentry *de)
 355 {
 356         int error;
 357         const char *name = de->d_name.name;
 358         int len = de->d_name.len;
 359
 360         lock_kernel();
 361         coda_vfs_stat.unlink++;
 362
 363         error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
 364         if ( error ) {
 365                 unlock_kernel();
 366                 return error;
 367         }
 368
 369         coda_dir_changed(dir, 0);
 370         de->d_inode->i_nlink--;
 371         unlock_kernel();
 372
 373         return 0;
 374 }
 375
 376 int coda_rmdir(struct inode *dir, struct dentry *de)
 377 {
 378         const char *name = de->d_name.name;
 379         int len = de->d_name.len;
 380         int error;
 381
 382         lock_kernel();
 383         coda_vfs_stat.rmdir++;
 384
 385         if (!d_unhashed(de)) {
 386                 unlock_kernel();
 387                 return -EBUSY;
 388         }
 389         error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
 390
 391         if ( error ) {
 392                 unlock_kernel();
 393                 return error;
 394         }
 395
 396         coda_dir_changed(dir, -1);
 397         de->d_inode->i_nlink--;
 398         d_delete(de);
 399         unlock_kernel();
 400
 401         return 0;
 402 }
 403
 404 /* rename */
 405 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
 406                        struct inode *new_dir, struct dentry *new_dentry)
 407 {
 408         const char *old_name = old_dentry->d_name.name;
 409         const char *new_name = new_dentry->d_name.name;
 410         int old_length = old_dentry->d_name.len;
 411         int new_length = new_dentry->d_name.len;
 412         int link_adjust = 0;
 413         int error;
 414
 415         lock_kernel();
 416         coda_vfs_stat.rename++;
 417
 418         error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
 419                              coda_i2f(new_dir), old_length, new_length,
 420                              (const char *) old_name, (const char *)new_name);
 421
 422         if ( !error ) {
 423                 if ( new_dentry->d_inode ) {
 424                         if ( S_ISDIR(new_dentry->d_inode->i_mode) )
 425                                 link_adjust = 1;
 426
 427                         coda_dir_changed(old_dir, -link_adjust);
 428                         coda_dir_changed(new_dir,  link_adjust);
 429                         coda_flag_inode(new_dentry->d_inode, C_VATTR);
 430                 } else {
 431                         coda_flag_inode(old_dir, C_VATTR);
 432                         coda_flag_inode(new_dir, C_VATTR);
 433                 }
 434         }
 435         unlock_kernel();
 436
 437         return error;
 438 }
 439
 440
 441 /* file operations for directories */
 442 int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
 443 {
 444         struct dentry *coda_dentry = coda_file->f_dentry;
 445         struct coda_file_info *cfi;
 446         struct file *host_file;
 447         struct inode *host_inode;
 448         int ret;
 449
 450         cfi = CODA_FTOC(coda_file);
 451         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 452         host_file = cfi->cfi_container;
 453
 454         coda_vfs_stat.readdir++;
 455
 456         host_inode = host_file->f_dentry->d_inode;
 457         mutex_lock(&host_inode->i_mutex);
 458         host_file->f_pos = coda_file->f_pos;
 459
 460         if (!host_file->f_op->readdir) {
 461                 /* Venus: we must read Venus dirents from the file */
 462                 ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
 463         } else {
 464                 /* potemkin case: we were handed a directory inode. */
 465                 /* Yuk, we can't call vfs_readdir because we are already
 466                  * holding the inode semaphore. */
 467                 ret = -ENOTDIR;
 468                 if (!host_file->f_op || !host_file->f_op->readdir)
 469                         goto out;
 470
 471                 ret = -ENOENT;
 472                 if (!IS_DEADDIR(host_inode)) {
 473                         ret = host_file->f_op->readdir(host_file, filldir, dirent);
 474                         file_accessed(host_file);
 475                 }
 476         }
 477 out:
 478         coda_file->f_pos = host_file->f_pos;
 479         mutex_unlock(&host_inode->i_mutex);
 480
 481         return ret;
 482 }
 483
 484 static inline unsigned int CDT2DT(unsigned char cdt)
 485 {
 486         unsigned int dt;
 487
 488         switch(cdt) {
 489         case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
 490         case CDT_FIFO:    dt = DT_FIFO;    break;
 491         case CDT_CHR:     dt = DT_CHR;     break;
 492         case CDT_DIR:     dt = DT_DIR;     break;
 493         case CDT_BLK:     dt = DT_BLK;     break;
 494         case CDT_REG:     dt = DT_REG;     break;
 495         case CDT_LNK:     dt = DT_LNK;     break;
 496         case CDT_SOCK:    dt = DT_SOCK;    break;
 497         case CDT_WHT:     dt = DT_WHT;     break;
 498         default:          dt = DT_UNKNOWN; break;
 499         }
 500         return dt;
 501 }
 502
 503 /* support routines */
 504 static int coda_venus_readdir(struct file *filp, filldir_t filldir,
 505                               void *dirent, struct dentry *dir)
 506 {
 507         int result = 0; /* # of entries returned */
 508         struct venus_dirent *vdir;
 509         unsigned long vdir_size =
 510             (unsigned long)(&((struct venus_dirent *)0)->d_name);
 511         unsigned int type;
 512         struct qstr name;
 513         ino_t ino;
 514         int ret, i;
 515
 516         vdir = (struct venus_dirent *)kmalloc(sizeof(*vdir), GFP_KERNEL);
 517         if (!vdir) return -ENOMEM;
 518
 519         i = filp->f_pos;
 520         switch(i) {
 521         case 0:
 522                 ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
 523                 if (ret < 0) break;
 524                 result++;
 525                 filp->f_pos++;
 526                 /* fallthrough */
 527         case 1:
 528                 ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
 529                 if (ret < 0) break;
 530                 result++;
 531                 filp->f_pos++;
 532                 /* fallthrough */
 533         default:
 534         while (1) {
 535                 /* read entries from the directory file */
 536                 ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
 537                                   sizeof(*vdir));
 538                 if (ret < 0) {
 539                         printk("coda_venus_readdir: read dir failed %d\n", ret);
 540                         break;
 541                 }
 542                 if (ret == 0) break; /* end of directory file reached */
 543
 544                 /* catch truncated reads */
 545                 if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
 546                         printk("coda_venus_readdir: short read: %ld\n",
 547                                filp->f_dentry->d_inode->i_ino);
 548                         ret = -EBADF;
 549                         break;
 550                 }
 551                 /* validate whether the directory file actually makes sense */
 552                 if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
 553                         printk("coda_venus_readdir: Invalid dir: %ld\n",
 554                                filp->f_dentry->d_inode->i_ino);
 555                         ret = -EBADF;
 556                         break;
 557                 }
 558
 559                 name.len = vdir->d_namlen;
 560                 name.name = vdir->d_name;
 561
 562                 /* Make sure we skip '.' and '..', we already got those */
 563                 if (name.name[0] == '.' && (name.len == 1 ||
 564                     (vdir->d_name[1] == '.' && name.len == 2)))
 565                         vdir->d_fileno = name.len = 0;
 566
 567                 /* skip null entries */
 568                 if (vdir->d_fileno && name.len) {
 569                         /* try to look up this entry in the dcache, that way
 570                          * userspace doesn't have to worry about breaking
 571                          * getcwd by having mismatched inode numbers for
 572                          * internal volume mountpoints. */
 573                         ino = find_inode_number(dir, &name);
 574                         if (!ino) ino = vdir->d_fileno;
 575
 576                         type = CDT2DT(vdir->d_type);
 577                         ret = filldir(dirent, name.name, name.len, filp->f_pos,
 578                                       ino, type);
 579                         /* failure means no space for filling in this round */
 580                         if (ret < 0) break;
 581                         result++;
 582                 }
 583                 /* we'll always have progress because d_reclen is unsigned and
 584                  * we've already established it is non-zero. */
 585                 filp->f_pos += vdir->d_reclen;
 586         }
 587         }
 588         kfree(vdir);
 589         return result ? result : ret;
 590 }
 591
 592 /* called when a cache lookup succeeds */
 593 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
 594 {
 595         struct inode *inode = de->d_inode;
 596         struct coda_inode_info *cii;
 597
 598         if (!inode)
 599                 return 1;
 600         lock_kernel();
 601         if (coda_isroot(inode))
 602                 goto out;
 603         if (is_bad_inode(inode))
 604                 goto bad;
 605
 606         cii = ITOC(de->d_inode);
 607         if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
 608                 goto out;
 609
 610         shrink_dcache_parent(de);
 611
 612         /* propagate for a flush */
 613         if (cii->c_flags & C_FLUSH)
 614                 coda_flag_inode_children(inode, C_FLUSH);
 615
 616         if (atomic_read(&de->d_count) > 1)
 617                 /* pretend it's valid, but don't change the flags */
 618                 goto out;
 619
 620         /* clear the flags. */
 621         cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
 622
 623 bad:
 624         unlock_kernel();
 625         return 0;
 626 out:
 627         unlock_kernel();
 628         return 1;
 629 }
 630
 631 /*
 632  * This is the callback from dput() when d_count is going to 0.
 633  * We use this to unhash dentries with bad inodes.
 634  */
 635 static int coda_dentry_delete(struct dentry * dentry)
 636 {
 637         int flags;
 638
 639         if (!dentry->d_inode)
 640                 return 0;
 641
 642         flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
 643         if (is_bad_inode(dentry->d_inode) || flags) {
 644                 return 1;
 645         }
 646         return 0;
 647 }
 648
 649
 650
 651 /*
 652  * This is called when we want to check if the inode has
 653  * changed on the server.  Coda makes this easy since the
 654  * cache manager Venus issues a downcall to the kernel when this
 655  * happens
 656  */
 657 int coda_revalidate_inode(struct dentry *dentry)
 658 {
 659         struct coda_vattr attr;
 660         int error = 0;
 661         int old_mode;
 662         ino_t old_ino;
 663         struct inode *inode = dentry->d_inode;
 664         struct coda_inode_info *cii = ITOC(inode);
 665
 666         lock_kernel();
 667         if ( !cii->c_flags )
 668                 goto ok;
 669
 670         if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
 671                 error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
 672                 if ( error )
 673                         goto return_bad;
 674
 675                 /* this inode may be lost if:
 676                    - it's ino changed
 677                    - type changes must be permitted for repair and
 678                    missing mount points.
 679                 */
 680                 old_mode = inode->i_mode;
 681                 old_ino = inode->i_ino;
 682                 coda_vattr_to_iattr(inode, &attr);
 683
 684                 if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
 685                         printk("Coda: inode %ld, fid %s changed type!\n",
 686                                inode->i_ino, coda_f2s(&(cii->c_fid)));
 687                 }
 688
 689                 /* the following can happen when a local fid is replaced
 690                    with a global one, here we lose and declare the inode bad */
 691                 if (inode->i_ino != old_ino)
 692                         goto return_bad;
 693
 694                 coda_flag_inode_children(inode, C_FLUSH);
 695                 cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
 696         }
 697
 698 ok:
 699         unlock_kernel();
 700         return 0;
 701
 702 return_bad:
 703         unlock_kernel();
 704         return -EIO;
 705 }