drivers/staging/pohmelfs/dir.c

   1 /*
   2  * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
   3  * All rights reserved.
   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 the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/fs.h>
  18 #include <linux/jhash.h>
  19 #include <linux/namei.h>
  20 #include <linux/pagemap.h>
  21
  22 #include "netfs.h"
  23
  24 static int pohmelfs_cmp_hash(struct pohmelfs_name *n, u32 hash)
  25 {
  26         if (n->hash > hash)
  27                 return -1;
  28         if (n->hash < hash)
  29                 return 1;
  30
  31         return 0;
  32 }
  33
  34 static struct pohmelfs_name *pohmelfs_search_hash_unprecise(struct pohmelfs_inode *pi, u32 hash)
  35 {
  36         struct rb_node *n = pi->hash_root.rb_node;
  37         struct pohmelfs_name *tmp = NULL;
  38         int cmp;
  39
  40         while (n) {
  41                 tmp = rb_entry(n, struct pohmelfs_name, hash_node);
  42
  43                 cmp = pohmelfs_cmp_hash(tmp, hash);
  44                 if (cmp < 0)
  45                         n = n->rb_left;
  46                 else if (cmp > 0)
  47                         n = n->rb_right;
  48                 else
  49                         break;
  50
  51         }
  52
  53         return tmp;
  54 }
  55
  56 struct pohmelfs_name *pohmelfs_search_hash(struct pohmelfs_inode *pi, u32 hash)
  57 {
  58         struct pohmelfs_name *tmp;
  59
  60         tmp = pohmelfs_search_hash_unprecise(pi, hash);
  61         if (tmp && (tmp->hash == hash))
  62                 return tmp;
  63
  64         return NULL;
  65 }
  66
  67 static void __pohmelfs_name_del(struct pohmelfs_inode *parent, struct pohmelfs_name *node)
  68 {
  69         rb_erase(&node->hash_node, &parent->hash_root);
  70 }
  71
  72 /*
  73  * Remove name cache entry from its caches and free it.
  74  */
  75 static void pohmelfs_name_free(struct pohmelfs_inode *parent, struct pohmelfs_name *node)
  76 {
  77         __pohmelfs_name_del(parent, node);
  78         list_del(&node->sync_create_entry);
  79         kfree(node);
  80 }
  81
  82 static struct pohmelfs_name *pohmelfs_insert_hash(struct pohmelfs_inode *pi,
  83                 struct pohmelfs_name *new)
  84 {
  85         struct rb_node **n = &pi->hash_root.rb_node, *parent = NULL;
  86         struct pohmelfs_name *ret = NULL, *tmp;
  87         int cmp;
  88
  89         while (*n) {
  90                 parent = *n;
  91
  92                 tmp = rb_entry(parent, struct pohmelfs_name, hash_node);
  93
  94                 cmp = pohmelfs_cmp_hash(tmp, new->hash);
  95                 if (cmp < 0)
  96                         n = &parent->rb_left;
  97                 else if (cmp > 0)
  98                         n = &parent->rb_right;
  99                 else {
 100                         ret = tmp;
 101                         break;
 102                 }
 103         }
 104
 105         if (ret) {
 106                 printk("%s: exist: parent: %llu, ino: %llu, hash: %x, len: %u, data: '%s', "
 107                                            "new: ino: %llu, hash: %x, len: %u, data: '%s'.\n",
 108                                 __func__, pi->ino,
 109                                 ret->ino, ret->hash, ret->len, ret->data,
 110                                 new->ino, new->hash, new->len, new->data);
 111                 ret->ino = new->ino;
 112                 return ret;
 113         }
 114
 115         rb_link_node(&new->hash_node, parent, n);
 116         rb_insert_color(&new->hash_node, &pi->hash_root);
 117
 118         return NULL;
 119 }
 120
 121 /*
 122  * Free name cache for given inode.
 123  */
 124 void pohmelfs_free_names(struct pohmelfs_inode *parent)
 125 {
 126         struct rb_node *rb_node;
 127         struct pohmelfs_name *n;
 128
 129         for (rb_node = rb_first(&parent->hash_root); rb_node;) {
 130                 n = rb_entry(rb_node, struct pohmelfs_name, hash_node);
 131                 rb_node = rb_next(rb_node);
 132
 133                 pohmelfs_name_free(parent, n);
 134         }
 135 }
 136
 137 static void pohmelfs_fix_offset(struct pohmelfs_inode *parent, struct pohmelfs_name *node)
 138 {
 139         parent->total_len -= node->len;
 140 }
 141
 142 /*
 143  * Free name cache entry helper.
 144  */
 145 void pohmelfs_name_del(struct pohmelfs_inode *parent, struct pohmelfs_name *node)
 146 {
 147         pohmelfs_fix_offset(parent, node);
 148         pohmelfs_name_free(parent, node);
 149 }
 150
 151 /*
 152  * Insert new name cache entry into all hash cache.
 153  */
 154 static int pohmelfs_insert_name(struct pohmelfs_inode *parent, struct pohmelfs_name *n)
 155 {
 156         struct pohmelfs_name *name;
 157
 158         name = pohmelfs_insert_hash(parent, n);
 159         if (name)
 160                 return -EEXIST;
 161
 162         parent->total_len += n->len;
 163         list_add_tail(&n->sync_create_entry, &parent->sync_create_list);
 164
 165         return 0;
 166 }
 167
 168 /*
 169  * Allocate new name cache entry.
 170  */
 171 static struct pohmelfs_name *pohmelfs_name_alloc(unsigned int len)
 172 {
 173         struct pohmelfs_name *n;
 174
 175         n = kzalloc(sizeof(struct pohmelfs_name) + len, GFP_KERNEL);
 176         if (!n)
 177                 return NULL;
 178
 179         INIT_LIST_HEAD(&n->sync_create_entry);
 180
 181         n->data = (char *)(n+1);
 182
 183         return n;
 184 }
 185
 186 /*
 187  * Add new name entry into directory's cache.
 188  */
 189 static int pohmelfs_add_dir(struct pohmelfs_sb *psb, struct pohmelfs_inode *parent,
 190                 struct pohmelfs_inode *npi, struct qstr *str, unsigned int mode, int link)
 191 {
 192         int err = -ENOMEM;
 193         struct pohmelfs_name *n;
 194
 195         n = pohmelfs_name_alloc(str->len + 1);
 196         if (!n)
 197                 goto err_out_exit;
 198
 199         n->ino = npi->ino;
 200         n->mode = mode;
 201         n->len = str->len;
 202         n->hash = str->hash;
 203         sprintf(n->data, "%s", str->name);
 204
 205         mutex_lock(&parent->offset_lock);
 206         err = pohmelfs_insert_name(parent, n);
 207         mutex_unlock(&parent->offset_lock);
 208
 209         if (err) {
 210                 if (err != -EEXIST)
 211                         goto err_out_free;
 212                 kfree(n);
 213         }
 214
 215         return 0;
 216
 217 err_out_free:
 218         kfree(n);
 219 err_out_exit:
 220         return err;
 221 }
 222
 223 /*
 224  * Create new inode for given parameters (name, inode info, parent).
 225  * This does not create object on the server, it will be synced there during writeback.
 226  */
 227 struct pohmelfs_inode *pohmelfs_new_inode(struct pohmelfs_sb *psb,
 228                 struct pohmelfs_inode *parent, struct qstr *str,
 229                 struct netfs_inode_info *info, int link)
 230 {
 231         struct inode *new = NULL;
 232         struct pohmelfs_inode *npi;
 233         int err = -EEXIST;
 234
 235         dprintk("%s: creating inode: parent: %llu, ino: %llu, str: %p.\n",
 236                         __func__, (parent)?parent->ino:0, info->ino, str);
 237
 238         err = -ENOMEM;
 239         new = iget_locked(psb->sb, info->ino);
 240         if (!new)
 241                 goto err_out_exit;
 242
 243         npi = POHMELFS_I(new);
 244         npi->ino = info->ino;
 245         err = 0;
 246
 247         if (new->i_state & I_NEW) {
 248                 dprintk("%s: filling VFS inode: %lu/%llu.\n",
 249                                 __func__, new->i_ino, info->ino);
 250                 pohmelfs_fill_inode(new, info);
 251
 252                 if (S_ISDIR(info->mode)) {
 253                         struct qstr s;
 254
 255                         s.name = ".";
 256                         s.len = 1;
 257                         s.hash = jhash(s.name, s.len, 0);
 258
 259                         err = pohmelfs_add_dir(psb, npi, npi, &s, info->mode, 0);
 260                         if (err)
 261                                 goto err_out_put;
 262
 263                         s.name = "..";
 264                         s.len = 2;
 265                         s.hash = jhash(s.name, s.len, 0);
 266
 267                         err = pohmelfs_add_dir(psb, npi, (parent)?parent:npi, &s,
 268                                         (parent)?parent->vfs_inode.i_mode:npi->vfs_inode.i_mode, 0);
 269                         if (err)
 270                                 goto err_out_put;
 271                 }
 272         }
 273
 274         if (str) {
 275                 if (parent) {
 276                         err = pohmelfs_add_dir(psb, parent, npi, str, info->mode, link);
 277
 278                         dprintk("%s: %s inserted name: '%s', new_offset: %llu, ino: %llu, parent: %llu.\n",
 279                                         __func__, (err)?"unsuccessfully":"successfully",
 280                                         str->name, parent->total_len, info->ino, parent->ino);
 281
 282                         if (err && err != -EEXIST)
 283                                 goto err_out_put;
 284                 }
 285         }
 286
 287         if (new->i_state & I_NEW) {
 288                 if (parent)
 289                         mark_inode_dirty(&parent->vfs_inode);
 290                 mark_inode_dirty(new);
 291         }
 292
 293         set_bit(NETFS_INODE_OWNED, &npi->state);
 294         npi->lock_type = POHMELFS_WRITE_LOCK;
 295         unlock_new_inode(new);
 296
 297         return npi;
 298
 299 err_out_put:
 300         printk("%s: putting inode: %p, npi: %p, error: %d.\n", __func__, new, npi, err);
 301         iput(new);
 302 err_out_exit:
 303         return ERR_PTR(err);
 304 }
 305
 306 static int pohmelfs_remote_sync_complete(struct page **pages, unsigned int page_num,
 307                 void *private, int err)
 308 {
 309         struct pohmelfs_inode *pi = private;
 310         struct pohmelfs_sb *psb = POHMELFS_SB(pi->vfs_inode.i_sb);
 311
 312         dprintk("%s: ino: %llu, err: %d.\n", __func__, pi->ino, err);
 313
 314         if (err)
 315                 pi->error = err;
 316         wake_up(&psb->wait);
 317         pohmelfs_put_inode(pi);
 318
 319         return err;
 320 }
 321
 322 /*
 323  * Receive directory content from the server.
 324  * This should be only done for objects, which were not created locally,
 325  * and which were not synced previously.
 326  */
 327 static int pohmelfs_sync_remote_dir(struct pohmelfs_inode *pi)
 328 {
 329         struct inode *inode = &pi->vfs_inode;
 330         struct pohmelfs_sb *psb = POHMELFS_SB(inode->i_sb);
 331         long ret = psb->wait_on_page_timeout;
 332         int err;
 333
 334         dprintk("%s: dir: %llu, state: %lx: remote_synced: %d.\n",
 335                 __func__, pi->ino, pi->state, test_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state));
 336
 337         if (test_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &pi->state))
 338                 return 0;
 339
 340         if (!igrab(inode)) {
 341                 err = -ENOENT;
 342                 goto err_out_exit;
 343         }
 344
 345         err = pohmelfs_meta_command(pi, NETFS_READDIR, NETFS_TRANS_SINGLE_DST,
 346                         pohmelfs_remote_sync_complete, pi, 0);
 347         if (err)
 348                 goto err_out_exit;
 349
 350         pi->error = 0;
 351         ret = wait_event_interruptible_timeout(psb->wait,
 352                         test_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &pi->state) || pi->error, ret);
 353         dprintk("%s: awake dir: %llu, ret: %ld, err: %d.\n", __func__, pi->ino, ret, pi->error);
 354         if (ret <= 0) {
 355                 err = -ETIMEDOUT;
 356                 goto err_out_exit;
 357         }
 358
 359         if (pi->error)
 360                 return pi->error;
 361
 362         return 0;
 363
 364 err_out_exit:
 365         clear_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state);
 366
 367         return err;
 368 }
 369
 370 static int pohmelfs_dir_open(struct inode *inode, struct file *file)
 371 {
 372         file->private_data = NULL;
 373         return 0;
 374 }
 375
 376 /*
 377  * VFS readdir callback. Syncs directory content from server if needed,
 378  * and provides direntry info to the userspace.
 379  */
 380 static int pohmelfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 381 {
 382         struct inode *inode = file->f_path.dentry->d_inode;
 383         struct pohmelfs_inode *pi = POHMELFS_I(inode);
 384         struct pohmelfs_name *n;
 385         struct rb_node *rb_node;
 386         int err = 0, mode;
 387         u64 len;
 388
 389         dprintk("%s: parent: %llu, fpos: %llu, hash: %08lx.\n",
 390                         __func__, pi->ino, (u64)file->f_pos,
 391                         (unsigned long)file->private_data);
 392 #if 0
 393         err = pohmelfs_data_lock(pi, 0, ~0, POHMELFS_READ_LOCK);
 394         if (err)
 395                 return err;
 396 #endif
 397         err = pohmelfs_sync_remote_dir(pi);
 398         if (err)
 399                 return err;
 400
 401         if (file->private_data && (file->private_data == (void *)(unsigned long)file->f_pos))
 402                 return 0;
 403
 404         mutex_lock(&pi->offset_lock);
 405         n = pohmelfs_search_hash_unprecise(pi, (unsigned long)file->private_data);
 406
 407         while (n) {
 408                 mode = (n->mode >> 12) & 15;
 409
 410                 dprintk("%s: offset: %llu, parent ino: %llu, name: '%s', len: %u, ino: %llu, "
 411                                 "mode: %o/%o, fpos: %llu, hash: %08x.\n",
 412                                 __func__, file->f_pos, pi->ino, n->data, n->len,
 413                                 n->ino, n->mode, mode, file->f_pos, n->hash);
 414
 415                 file->private_data = (void *)n->hash;
 416
 417                 len = n->len;
 418                 err = filldir(dirent, n->data, n->len, file->f_pos, n->ino, mode);
 419
 420                 if (err < 0) {
 421                         dprintk("%s: err: %d.\n", __func__, err);
 422                         err = 0;
 423                         break;
 424                 }
 425
 426                 file->f_pos += len;
 427
 428                 rb_node = rb_next(&n->hash_node);
 429
 430                 if (!rb_node || (rb_node == &n->hash_node)) {
 431                         file->private_data = (void *)(unsigned long)file->f_pos;
 432                         break;
 433                 }
 434
 435                 n = rb_entry(rb_node, struct pohmelfs_name, hash_node);
 436         }
 437         mutex_unlock(&pi->offset_lock);
 438
 439         return err;
 440 }
 441
 442 static loff_t pohmelfs_dir_lseek(struct file *file, loff_t offset, int origin)
 443 {
 444         file->f_pos = offset;
 445         file->private_data = NULL;
 446         return offset;
 447 }
 448
 449 const struct file_operations pohmelfs_dir_fops = {
 450         .open = pohmelfs_dir_open,
 451         .read = generic_read_dir,
 452         .llseek = pohmelfs_dir_lseek,
 453         .readdir = pohmelfs_readdir,
 454 };
 455
 456 /*
 457  * Lookup single object on server.
 458  */
 459 static int pohmelfs_lookup_single(struct pohmelfs_inode *parent,
 460                 struct qstr *str, u64 ino)
 461 {
 462         struct pohmelfs_sb *psb = POHMELFS_SB(parent->vfs_inode.i_sb);
 463         long ret = msecs_to_jiffies(5000);
 464         int err;
 465
 466         set_bit(NETFS_COMMAND_PENDING, &parent->state);
 467         err = pohmelfs_meta_command_data(parent, parent->ino, NETFS_LOOKUP,
 468                         (char *)str->name, NETFS_TRANS_SINGLE_DST, NULL, NULL, ino);
 469         if (err)
 470                 goto err_out_exit;
 471
 472         err = 0;
 473         ret = wait_event_interruptible_timeout(psb->wait,
 474                         !test_bit(NETFS_COMMAND_PENDING, &parent->state), ret);
 475         if (ret == 0)
 476                 err = -ETIMEDOUT;
 477         else if (signal_pending(current))
 478                 err = -EINTR;
 479
 480         if (err)
 481                 goto err_out_exit;
 482
 483         return 0;
 484
 485 err_out_exit:
 486         clear_bit(NETFS_COMMAND_PENDING, &parent->state);
 487
 488         printk("%s: failed: parent: %llu, ino: %llu, name: '%s', err: %d.\n",
 489                         __func__, parent->ino, ino, str->name, err);
 490
 491         return err;
 492 }
 493
 494 /*
 495  * VFS lookup callback.
 496  * We first try to get inode number from local name cache, if we have one,
 497  * then inode can be found in inode cache. If there is no inode or no object in
 498  * local cache, try to lookup it on server. This only should be done for directories,
 499  * which were not created locally, otherwise remote server does not know about dir at all,
 500  * so no need to try to know that.
 501  */
 502 struct dentry *pohmelfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 503 {
 504         struct pohmelfs_inode *parent = POHMELFS_I(dir);
 505         struct pohmelfs_name *n;
 506         struct inode *inode = NULL;
 507         unsigned long ino = 0;
 508         int err, lock_type = POHMELFS_READ_LOCK, need_lock;
 509         struct qstr str = dentry->d_name;
 510
 511         if ((nd->intent.open.flags & O_ACCMODE) > 1)
 512                 lock_type = POHMELFS_WRITE_LOCK;
 513
 514         need_lock = pohmelfs_need_lock(parent, lock_type);
 515
 516         str.hash = jhash(dentry->d_name.name, dentry->d_name.len, 0);
 517
 518         mutex_lock(&parent->offset_lock);
 519         n = pohmelfs_search_hash(parent, str.hash);
 520         if (n)
 521                 ino = n->ino;
 522         mutex_unlock(&parent->offset_lock);
 523
 524         dprintk("%s: start ino: %lu, inode: %p, name: '%s', hash: %x, parent_state: %lx, need_lock: %d.\n",
 525                         __func__, ino, inode, str.name, str.hash, parent->state, need_lock);
 526
 527         if (ino) {
 528                 inode = ilookup(dir->i_sb, ino);
 529                 if (inode)
 530                         goto out;
 531         }
 532
 533         dprintk("%s: no inode dir: %p, dir_ino: %llu, name: '%s', len: %u, dir_state: %lx, ino: %lu.\n",
 534                         __func__, dir, parent->ino,
 535                         str.name, str.len, parent->state, ino);
 536
 537         if (!ino) {
 538                 if (!need_lock)
 539                         goto out;
 540         }
 541
 542         err = pohmelfs_data_lock(parent, 0, ~0, lock_type);
 543         if (err)
 544                 goto out;
 545
 546         err = pohmelfs_lookup_single(parent, &str, ino);
 547         if (err)
 548                 goto out;
 549
 550         if (!ino) {
 551                 mutex_lock(&parent->offset_lock);
 552                 n = pohmelfs_search_hash(parent, str.hash);
 553                 if (n)
 554                         ino = n->ino;
 555                 mutex_unlock(&parent->offset_lock);
 556         }
 557
 558         if (ino) {
 559                 inode = ilookup(dir->i_sb, ino);
 560                 dprintk("%s: second lookup ino: %lu, inode: %p, name: '%s', hash: %x.\n",
 561                                 __func__, ino, inode, str.name, str.hash);
 562                 if (!inode) {
 563                         dprintk("%s: No inode for ino: %lu, name: '%s', hash: %x.\n",
 564                                 __func__, ino, str.name, str.hash);
 565                         //return NULL;
 566                         return ERR_PTR(-EACCES);
 567                 }
 568         } else {
 569                 printk("%s: No inode number : name: '%s', hash: %x.\n",
 570                         __func__, str.name, str.hash);
 571         }
 572 out:
 573         return d_splice_alias(inode, dentry);
 574 }
 575
 576 /*
 577  * Create new object in local cache. Object will be synced to server
 578  * during writeback for given inode.
 579  */
 580 struct pohmelfs_inode *pohmelfs_create_entry_local(struct pohmelfs_sb *psb,
 581         struct pohmelfs_inode *parent, struct qstr *str, u64 start, int mode)
 582 {
 583         struct pohmelfs_inode *npi;
 584         int err = -ENOMEM;
 585         struct netfs_inode_info info;
 586
 587         dprintk("%s: name: '%s', mode: %o, start: %llu.\n",
 588                         __func__, str->name, mode, start);
 589
 590         info.mode = mode;
 591         info.ino = start;
 592
 593         if (!start)
 594                 info.ino = pohmelfs_new_ino(psb);
 595
 596         info.nlink = S_ISDIR(mode)?2:1;
 597         info.uid = current_fsuid();
 598         info.gid = current_fsgid();
 599         info.size = 0;
 600         info.blocksize = 512;
 601         info.blocks = 0;
 602         info.rdev = 0;
 603         info.version = 0;
 604
 605         npi = pohmelfs_new_inode(psb, parent, str, &info, !!start);
 606         if (IS_ERR(npi)) {
 607                 err = PTR_ERR(npi);
 608                 goto err_out_unlock;
 609         }
 610
 611         return npi;
 612
 613 err_out_unlock:
 614         dprintk("%s: err: %d.\n", __func__, err);
 615         return ERR_PTR(err);
 616 }
 617
 618 /*
 619  * Create local object and bind it to dentry.
 620  */
 621 static int pohmelfs_create_entry(struct inode *dir, struct dentry *dentry, u64 start, int mode)
 622 {
 623         struct pohmelfs_sb *psb = POHMELFS_SB(dir->i_sb);
 624         struct pohmelfs_inode *npi, *parent;
 625         struct qstr str = dentry->d_name;
 626         int err;
 627
 628         parent = POHMELFS_I(dir);
 629
 630         err = pohmelfs_data_lock(parent, 0, ~0, POHMELFS_WRITE_LOCK);
 631         if (err)
 632                 return err;
 633
 634         str.hash = jhash(dentry->d_name.name, dentry->d_name.len, 0);
 635
 636         npi = pohmelfs_create_entry_local(psb, parent, &str, start, mode);
 637         if (IS_ERR(npi))
 638                 return PTR_ERR(npi);
 639
 640         d_instantiate(dentry, &npi->vfs_inode);
 641
 642         dprintk("%s: parent: %llu, inode: %llu, name: '%s', parent_nlink: %d, nlink: %d.\n",
 643                         __func__, parent->ino, npi->ino, dentry->d_name.name,
 644                         (signed)dir->i_nlink, (signed)npi->vfs_inode.i_nlink);
 645
 646         return 0;
 647 }
 648
 649 /*
 650  * VFS create and mkdir callbacks.
 651  */
 652 static int pohmelfs_create(struct inode *dir, struct dentry *dentry, int mode,
 653                 struct nameidata *nd)
 654 {
 655         return pohmelfs_create_entry(dir, dentry, 0, mode);
 656 }
 657
 658 static int pohmelfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 659 {
 660         int err;
 661
 662         inode_inc_link_count(dir);
 663         err = pohmelfs_create_entry(dir, dentry, 0, mode | S_IFDIR);
 664         if (err)
 665                 inode_dec_link_count(dir);
 666
 667         return err;
 668 }
 669
 670 static int pohmelfs_remove_entry(struct inode *dir, struct dentry *dentry)
 671 {
 672         struct pohmelfs_sb *psb = POHMELFS_SB(dir->i_sb);
 673         struct inode *inode = dentry->d_inode;
 674         struct pohmelfs_inode *parent = POHMELFS_I(dir), *pi = POHMELFS_I(inode);
 675         struct pohmelfs_name *n;
 676         int err = -ENOENT;
 677         struct qstr str = dentry->d_name;
 678
 679         err = pohmelfs_data_lock(parent, 0, ~0, POHMELFS_WRITE_LOCK);
 680         if (err)
 681                 return err;
 682
 683         str.hash = jhash(dentry->d_name.name, dentry->d_name.len, 0);
 684
 685         dprintk("%s: dir_ino: %llu, inode: %llu, name: '%s', nlink: %d.\n",
 686                         __func__, parent->ino, pi->ino,
 687                         str.name, (signed)inode->i_nlink);
 688
 689         BUG_ON(!inode);
 690
 691         mutex_lock(&parent->offset_lock);
 692         n = pohmelfs_search_hash(parent, str.hash);
 693         if (n) {
 694                 pohmelfs_fix_offset(parent, n);
 695                 if (test_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state)) {
 696                         pohmelfs_remove_child(pi, n);
 697                 }
 698                 pohmelfs_name_free(parent, n);
 699                 err = 0;
 700         }
 701         mutex_unlock(&parent->offset_lock);
 702
 703         if (!err) {
 704                 psb->avail_size += inode->i_size;
 705
 706                 pohmelfs_inode_del_inode(psb, pi);
 707
 708                 mark_inode_dirty(dir);
 709
 710                 inode->i_ctime = dir->i_ctime;
 711                 if (inode->i_nlink)
 712                         inode_dec_link_count(inode);
 713         }
 714         dprintk("%s: inode: %p, lock: %ld, unhashed: %d.\n",
 715                 __func__, pi, inode->i_state & I_LOCK, hlist_unhashed(&inode->i_hash));
 716
 717         return err;
 718 }
 719
 720 /*
 721  * Unlink and rmdir VFS callbacks.
 722  */
 723 static int pohmelfs_unlink(struct inode *dir, struct dentry *dentry)
 724 {
 725         return pohmelfs_remove_entry(dir, dentry);
 726 }
 727
 728 static int pohmelfs_rmdir(struct inode *dir, struct dentry *dentry)
 729 {
 730         int err;
 731         struct inode *inode = dentry->d_inode;
 732
 733         dprintk("%s: parent: %llu, inode: %llu, name: '%s', parent_nlink: %d, nlink: %d.\n",
 734                         __func__, POHMELFS_I(dir)->ino, POHMELFS_I(inode)->ino,
 735                         dentry->d_name.name, (signed)dir->i_nlink, (signed)inode->i_nlink);
 736
 737         err = pohmelfs_remove_entry(dir, dentry);
 738         if (!err) {
 739                 inode_dec_link_count(dir);
 740                 inode_dec_link_count(inode);
 741         }
 742
 743         return err;
 744 }
 745
 746 /*
 747  * Link creation is synchronous.
 748  * I'm lazy.
 749  * Earth is somewhat round.
 750  */
 751 static int pohmelfs_create_link(struct pohmelfs_inode *parent, struct qstr *obj,
 752                 struct pohmelfs_inode *target, struct qstr *tstr)
 753 {
 754         struct super_block *sb = parent->vfs_inode.i_sb;
 755         struct pohmelfs_sb *psb = POHMELFS_SB(sb);
 756         struct netfs_cmd *cmd;
 757         struct netfs_trans *t;
 758         void *data;
 759         int err, parent_len, target_len = 0, cur_len, path_size = 0;
 760
 761         err = pohmelfs_data_lock(parent, 0, ~0, POHMELFS_WRITE_LOCK);
 762         if (err)
 763                 return err;
 764
 765         err = sb->s_op->write_inode(&parent->vfs_inode, 0);
 766         if (err)
 767                 goto err_out_exit;
 768
 769         if (tstr)
 770                 target_len = tstr->len;
 771
 772         parent_len = pohmelfs_path_length(parent);
 773         if (target)
 774                 target_len += pohmelfs_path_length(target);
 775
 776         if (parent_len < 0) {
 777                 err = parent_len;
 778                 goto err_out_exit;
 779         }
 780
 781         if (target_len < 0) {
 782                 err = target_len;
 783                 goto err_out_exit;
 784         }
 785
 786         t = netfs_trans_alloc(psb, parent_len + target_len + obj->len + 2, 0, 0);
 787         if (!t) {
 788                 err = -ENOMEM;
 789                 goto err_out_exit;
 790         }
 791         cur_len = netfs_trans_cur_len(t);
 792
 793         cmd = netfs_trans_current(t);
 794         if (IS_ERR(cmd)) {
 795                 err = PTR_ERR(cmd);
 796                 goto err_out_free;
 797         }
 798
 799         data = (void *)(cmd + 1);
 800         cur_len -= sizeof(struct netfs_cmd);
 801
 802         err = pohmelfs_construct_path_string(parent, data, parent_len);
 803         if (err > 0) {
 804                 /* Do not place null-byte before the slash */
 805                 path_size = err - 1;
 806                 cur_len -= path_size;
 807
 808                 err = snprintf(data + path_size, cur_len, "/%s|", obj->name);
 809
 810                 path_size += err;
 811                 cur_len -= err;
 812
 813                 cmd->ext = path_size - 1; /* No | symbol */
 814
 815                 if (target) {
 816                         err = pohmelfs_construct_path_string(target, data + path_size, target_len);
 817                         if (err > 0) {
 818                                 path_size += err;
 819                                 cur_len -= err;
 820                         }
 821                 }
 822         }
 823
 824         if (err < 0)
 825                 goto err_out_free;
 826
 827         cmd->start = 0;
 828
 829         if (!target && tstr) {
 830                 if (tstr->len > cur_len - 1) {
 831                         err = -ENAMETOOLONG;
 832                         goto err_out_free;
 833                 }
 834
 835                 err = snprintf(data + path_size, cur_len, "%s", tstr->name) + 1; /* 0-byte */
 836                 path_size += err;
 837                 cur_len -= err;
 838                 cmd->start = 1;
 839         }
 840
 841         dprintk("%s: parent: %llu, obj: '%s', target_inode: %llu, target_str: '%s', full: '%s'.\n",
 842                         __func__, parent->ino, obj->name, (target)?target->ino:0, (tstr)?tstr->name:NULL,
 843                         (char *)data);
 844
 845         cmd->cmd = NETFS_LINK;
 846         cmd->size = path_size;
 847         cmd->id = parent->ino;
 848
 849         netfs_convert_cmd(cmd);
 850
 851         netfs_trans_update(cmd, t, path_size);
 852
 853         err = netfs_trans_finish(t, psb);
 854         if (err)
 855                 goto err_out_exit;
 856
 857         return 0;
 858
 859 err_out_free:
 860         t->result = err;
 861         netfs_trans_put(t);
 862 err_out_exit:
 863         return err;
 864 }
 865
 866 /*
 867  *  VFS hard and soft link callbacks.
 868  */
 869 static int pohmelfs_link(struct dentry *old_dentry, struct inode *dir,
 870         struct dentry *dentry)
 871 {
 872         struct inode *inode = old_dentry->d_inode;
 873         struct pohmelfs_inode *pi = POHMELFS_I(inode);
 874         int err;
 875         struct qstr str = dentry->d_name;
 876
 877         str.hash = jhash(dentry->d_name.name, dentry->d_name.len, 0);
 878
 879         err = inode->i_sb->s_op->write_inode(inode, 0);
 880         if (err)
 881                 return err;
 882
 883         err = pohmelfs_create_link(POHMELFS_I(dir), &str, pi, NULL);
 884         if (err)
 885                 return err;
 886
 887         return pohmelfs_create_entry(dir, dentry, pi->ino, inode->i_mode);
 888 }
 889
 890 static int pohmelfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 891 {
 892         struct qstr sym_str;
 893         struct qstr str = dentry->d_name;
 894         struct inode *inode;
 895         int err;
 896
 897         str.hash = jhash(dentry->d_name.name, dentry->d_name.len, 0);
 898
 899         sym_str.name = symname;
 900         sym_str.len = strlen(symname);
 901
 902         err = pohmelfs_create_link(POHMELFS_I(dir), &str, NULL, &sym_str);
 903         if (err)
 904                 goto err_out_exit;
 905
 906         err = pohmelfs_create_entry(dir, dentry, 0, S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO);
 907         if (err)
 908                 goto err_out_exit;
 909
 910         inode = dentry->d_inode;
 911
 912         err = page_symlink(inode, symname, sym_str.len + 1);
 913         if (err)
 914                 goto err_out_put;
 915
 916         return 0;
 917
 918 err_out_put:
 919         iput(inode);
 920 err_out_exit:
 921         return err;
 922 }
 923
 924 static int pohmelfs_send_rename(struct pohmelfs_inode *pi, struct pohmelfs_inode *parent,
 925                 struct qstr *str)
 926 {
 927         int path_len, err, total_len = 0, inode_len, parent_len;
 928         char *path;
 929         struct netfs_trans *t;
 930         struct netfs_cmd *cmd;
 931         struct pohmelfs_sb *psb = POHMELFS_SB(pi->vfs_inode.i_sb);
 932
 933         parent_len = pohmelfs_path_length(parent);
 934         inode_len = pohmelfs_path_length(pi);
 935
 936         if (parent_len < 0 || inode_len < 0)
 937                 return -EINVAL;
 938
 939         path_len = parent_len + inode_len + str->len + 3;
 940
 941         t = netfs_trans_alloc(psb, path_len, 0, 0);
 942         if (!t)
 943                 return -ENOMEM;
 944
 945         cmd = netfs_trans_current(t);
 946         path = (char *)(cmd + 1);
 947
 948         err = pohmelfs_construct_path_string(pi, path, inode_len);
 949         if (err < 0)
 950                 goto err_out_unlock;
 951
 952         cmd->ext = err;
 953
 954         path += err;
 955         total_len += err;
 956         path_len -= err;
 957
 958         *path = '|';
 959         path++;
 960         total_len++;
 961         path_len--;
 962
 963         err = pohmelfs_construct_path_string(parent, path, parent_len);
 964         if (err < 0)
 965                 goto err_out_unlock;
 966
 967         /*
 968          * Do not place a null-byte before the final slash and the name.
 969          */
 970         err--;
 971         path += err;
 972         total_len += err;
 973         path_len -= err;
 974
 975         err = snprintf(path, path_len - 1, "/%s", str->name);
 976
 977         total_len += err + 1; /* 0 symbol */
 978         path_len -= err + 1;
 979
 980         cmd->cmd = NETFS_RENAME;
 981         cmd->id = pi->ino;
 982         cmd->start = parent->ino;
 983         cmd->size = total_len;
 984
 985         netfs_convert_cmd(cmd);
 986
 987         netfs_trans_update(cmd, t, total_len);
 988
 989         return netfs_trans_finish(t, psb);
 990
 991 err_out_unlock:
 992         netfs_trans_free(t);
 993         return err;
 994 }
 995
 996 static int pohmelfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 997                         struct inode *new_dir, struct dentry *new_dentry)
 998 {
 999         struct inode *inode = old_dentry->d_inode;
1000         struct pohmelfs_inode *old_parent, *pi, *new_parent;
1001         struct qstr str = new_dentry->d_name;
1002         struct pohmelfs_name *n;
1003         unsigned int old_hash;
1004         int err = -ENOENT;
1005
1006         pi = POHMELFS_I(inode);
1007         old_parent = POHMELFS_I(old_dir);
1008
1009         if (new_dir) {
1010                 new_dir->i_sb->s_op->write_inode(new_dir, 0);
1011         }
1012
1013         old_hash = jhash(old_dentry->d_name.name, old_dentry->d_name.len, 0);
1014         str.hash = jhash(new_dentry->d_name.name, new_dentry->d_name.len, 0);
1015
1016         str.len = new_dentry->d_name.len;
1017         str.name = new_dentry->d_name.name;
1018         str.hash = jhash(new_dentry->d_name.name, new_dentry->d_name.len, 0);
1019
1020         if (new_dir) {
1021                 new_parent = POHMELFS_I(new_dir);
1022                 err = -ENOTEMPTY;
1023
1024                 if (S_ISDIR(inode->i_mode) &&
1025                                 new_parent->total_len <= 3)
1026                         goto err_out_exit;
1027         } else {
1028                 new_parent = old_parent;
1029         }
1030
1031         dprintk("%s: ino: %llu, parent: %llu, name: '%s' -> parent: %llu, name: '%s', i_size: %llu.\n",
1032                         __func__, pi->ino, old_parent->ino, old_dentry->d_name.name,
1033                         new_parent->ino, new_dentry->d_name.name, inode->i_size);
1034
1035         if (test_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state) &&
1036                         test_bit(NETFS_INODE_OWNED, &pi->state)) {
1037                 err = pohmelfs_send_rename(pi, new_parent, &str);
1038                 if (err)
1039                         goto err_out_exit;
1040         }
1041
1042         n = pohmelfs_name_alloc(str.len + 1);
1043         if (!n)
1044                 goto err_out_exit;
1045
1046         mutex_lock(&new_parent->offset_lock);
1047         n->ino = pi->ino;
1048         n->mode = inode->i_mode;
1049         n->len = str.len;
1050         n->hash = str.hash;
1051         sprintf(n->data, "%s", str.name);
1052
1053         err = pohmelfs_insert_name(new_parent, n);
1054         mutex_unlock(&new_parent->offset_lock);
1055
1056         if (err)
1057                 goto err_out_exit;
1058
1059         mutex_lock(&old_parent->offset_lock);
1060         n = pohmelfs_search_hash(old_parent, old_hash);
1061         if (n)
1062                 pohmelfs_name_del(old_parent, n);
1063         mutex_unlock(&old_parent->offset_lock);
1064
1065         mark_inode_dirty(inode);
1066         mark_inode_dirty(&new_parent->vfs_inode);
1067
1068         WARN_ON_ONCE(list_empty(&inode->i_dentry));
1069
1070         return 0;
1071
1072 err_out_exit:
1073
1074         clear_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state);
1075
1076         mutex_unlock(&inode->i_mutex);
1077         return err;
1078 }
1079
1080 /*
1081  * POHMELFS directory inode operations.
1082  */
1083 const struct inode_operations pohmelfs_dir_inode_ops = {
1084         .link           = pohmelfs_link,
1085         .symlink        = pohmelfs_symlink,
1086         .unlink         = pohmelfs_unlink,
1087         .mkdir          = pohmelfs_mkdir,
1088         .rmdir          = pohmelfs_rmdir,
1089         .create         = pohmelfs_create,
1090         .lookup         = pohmelfs_lookup,
1091         .setattr        = pohmelfs_setattr,
1092         .rename         = pohmelfs_rename,
1093 };