Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of UBIFS. |
| 3 | * |
| 4 | * Copyright (C) 2006-2008 Nokia Corporation. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License version 2 as published by |
| 8 | * the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 13 | * more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License along with |
| 16 | * this program; if not, write to the Free Software Foundation, Inc., 51 |
| 17 | * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | * |
| 19 | * Authors: Adrian Hunter |
| 20 | * Artem Bityutskiy (Битюцкий Артём) |
| 21 | */ |
| 22 | |
| 23 | /* |
| 24 | * This file implements TNC (Tree Node Cache) which caches indexing nodes of |
| 25 | * the UBIFS B-tree. |
| 26 | * |
| 27 | * At the moment the locking rules of the TNC tree are quite simple and |
| 28 | * straightforward. We just have a mutex and lock it when we traverse the |
| 29 | * tree. If a znode is not in memory, we read it from flash while still having |
| 30 | * the mutex locked. |
| 31 | */ |
| 32 | |
| 33 | #include <linux/crc32.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 34 | #include <linux/slab.h> |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 35 | #include "ubifs.h" |
| 36 | |
| 37 | /* |
| 38 | * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions. |
| 39 | * @NAME_LESS: name corresponding to the first argument is less than second |
| 40 | * @NAME_MATCHES: names match |
| 41 | * @NAME_GREATER: name corresponding to the second argument is greater than |
| 42 | * first |
| 43 | * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media |
| 44 | * |
| 45 | * These constants were introduce to improve readability. |
| 46 | */ |
| 47 | enum { |
| 48 | NAME_LESS = 0, |
| 49 | NAME_MATCHES = 1, |
| 50 | NAME_GREATER = 2, |
| 51 | NOT_ON_MEDIA = 3, |
| 52 | }; |
| 53 | |
| 54 | /** |
| 55 | * insert_old_idx - record an index node obsoleted since the last commit start. |
| 56 | * @c: UBIFS file-system description object |
| 57 | * @lnum: LEB number of obsoleted index node |
| 58 | * @offs: offset of obsoleted index node |
| 59 | * |
| 60 | * Returns %0 on success, and a negative error code on failure. |
| 61 | * |
| 62 | * For recovery, there must always be a complete intact version of the index on |
| 63 | * flash at all times. That is called the "old index". It is the index as at the |
| 64 | * time of the last successful commit. Many of the index nodes in the old index |
| 65 | * may be dirty, but they must not be erased until the next successful commit |
| 66 | * (at which point that index becomes the old index). |
| 67 | * |
| 68 | * That means that the garbage collection and the in-the-gaps method of |
| 69 | * committing must be able to determine if an index node is in the old index. |
| 70 | * Most of the old index nodes can be found by looking up the TNC using the |
| 71 | * 'lookup_znode()' function. However, some of the old index nodes may have |
| 72 | * been deleted from the current index or may have been changed so much that |
| 73 | * they cannot be easily found. In those cases, an entry is added to an RB-tree. |
| 74 | * That is what this function does. The RB-tree is ordered by LEB number and |
| 75 | * offset because they uniquely identify the old index node. |
| 76 | */ |
| 77 | static int insert_old_idx(struct ubifs_info *c, int lnum, int offs) |
| 78 | { |
| 79 | struct ubifs_old_idx *old_idx, *o; |
| 80 | struct rb_node **p, *parent = NULL; |
| 81 | |
| 82 | old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS); |
| 83 | if (unlikely(!old_idx)) |
| 84 | return -ENOMEM; |
| 85 | old_idx->lnum = lnum; |
| 86 | old_idx->offs = offs; |
| 87 | |
| 88 | p = &c->old_idx.rb_node; |
| 89 | while (*p) { |
| 90 | parent = *p; |
| 91 | o = rb_entry(parent, struct ubifs_old_idx, rb); |
| 92 | if (lnum < o->lnum) |
| 93 | p = &(*p)->rb_left; |
| 94 | else if (lnum > o->lnum) |
| 95 | p = &(*p)->rb_right; |
| 96 | else if (offs < o->offs) |
| 97 | p = &(*p)->rb_left; |
| 98 | else if (offs > o->offs) |
| 99 | p = &(*p)->rb_right; |
| 100 | else { |
| 101 | ubifs_err("old idx added twice!"); |
| 102 | kfree(old_idx); |
| 103 | return 0; |
| 104 | } |
| 105 | } |
| 106 | rb_link_node(&old_idx->rb, parent, p); |
| 107 | rb_insert_color(&old_idx->rb, &c->old_idx); |
| 108 | return 0; |
| 109 | } |
| 110 | |
| 111 | /** |
| 112 | * insert_old_idx_znode - record a znode obsoleted since last commit start. |
| 113 | * @c: UBIFS file-system description object |
| 114 | * @znode: znode of obsoleted index node |
| 115 | * |
| 116 | * Returns %0 on success, and a negative error code on failure. |
| 117 | */ |
| 118 | int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode) |
| 119 | { |
| 120 | if (znode->parent) { |
| 121 | struct ubifs_zbranch *zbr; |
| 122 | |
| 123 | zbr = &znode->parent->zbranch[znode->iip]; |
| 124 | if (zbr->len) |
| 125 | return insert_old_idx(c, zbr->lnum, zbr->offs); |
| 126 | } else |
| 127 | if (c->zroot.len) |
| 128 | return insert_old_idx(c, c->zroot.lnum, |
| 129 | c->zroot.offs); |
| 130 | return 0; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * ins_clr_old_idx_znode - record a znode obsoleted since last commit start. |
| 135 | * @c: UBIFS file-system description object |
| 136 | * @znode: znode of obsoleted index node |
| 137 | * |
| 138 | * Returns %0 on success, and a negative error code on failure. |
| 139 | */ |
| 140 | static int ins_clr_old_idx_znode(struct ubifs_info *c, |
| 141 | struct ubifs_znode *znode) |
| 142 | { |
| 143 | int err; |
| 144 | |
| 145 | if (znode->parent) { |
| 146 | struct ubifs_zbranch *zbr; |
| 147 | |
| 148 | zbr = &znode->parent->zbranch[znode->iip]; |
| 149 | if (zbr->len) { |
| 150 | err = insert_old_idx(c, zbr->lnum, zbr->offs); |
| 151 | if (err) |
| 152 | return err; |
| 153 | zbr->lnum = 0; |
| 154 | zbr->offs = 0; |
| 155 | zbr->len = 0; |
| 156 | } |
| 157 | } else |
| 158 | if (c->zroot.len) { |
| 159 | err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs); |
| 160 | if (err) |
| 161 | return err; |
| 162 | c->zroot.lnum = 0; |
| 163 | c->zroot.offs = 0; |
| 164 | c->zroot.len = 0; |
| 165 | } |
| 166 | return 0; |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * destroy_old_idx - destroy the old_idx RB-tree. |
| 171 | * @c: UBIFS file-system description object |
| 172 | * |
| 173 | * During start commit, the old_idx RB-tree is used to avoid overwriting index |
| 174 | * nodes that were in the index last commit but have since been deleted. This |
| 175 | * is necessary for recovery i.e. the old index must be kept intact until the |
| 176 | * new index is successfully written. The old-idx RB-tree is used for the |
| 177 | * in-the-gaps method of writing index nodes and is destroyed every commit. |
| 178 | */ |
| 179 | void destroy_old_idx(struct ubifs_info *c) |
| 180 | { |
| 181 | struct rb_node *this = c->old_idx.rb_node; |
| 182 | struct ubifs_old_idx *old_idx; |
| 183 | |
| 184 | while (this) { |
| 185 | if (this->rb_left) { |
| 186 | this = this->rb_left; |
| 187 | continue; |
| 188 | } else if (this->rb_right) { |
| 189 | this = this->rb_right; |
| 190 | continue; |
| 191 | } |
| 192 | old_idx = rb_entry(this, struct ubifs_old_idx, rb); |
| 193 | this = rb_parent(this); |
| 194 | if (this) { |
| 195 | if (this->rb_left == &old_idx->rb) |
| 196 | this->rb_left = NULL; |
| 197 | else |
| 198 | this->rb_right = NULL; |
| 199 | } |
| 200 | kfree(old_idx); |
| 201 | } |
| 202 | c->old_idx = RB_ROOT; |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * copy_znode - copy a dirty znode. |
| 207 | * @c: UBIFS file-system description object |
| 208 | * @znode: znode to copy |
| 209 | * |
| 210 | * A dirty znode being committed may not be changed, so it is copied. |
| 211 | */ |
| 212 | static struct ubifs_znode *copy_znode(struct ubifs_info *c, |
| 213 | struct ubifs_znode *znode) |
| 214 | { |
| 215 | struct ubifs_znode *zn; |
| 216 | |
| 217 | zn = kmalloc(c->max_znode_sz, GFP_NOFS); |
| 218 | if (unlikely(!zn)) |
| 219 | return ERR_PTR(-ENOMEM); |
| 220 | |
| 221 | memcpy(zn, znode, c->max_znode_sz); |
| 222 | zn->cnext = NULL; |
| 223 | __set_bit(DIRTY_ZNODE, &zn->flags); |
| 224 | __clear_bit(COW_ZNODE, &zn->flags); |
| 225 | |
Artem Bityutskiy | f42eed7 | 2011-05-30 14:45:30 +0300 | [diff] [blame] | 226 | ubifs_assert(!ubifs_zn_obsolete(znode)); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 227 | __set_bit(OBSOLETE_ZNODE, &znode->flags); |
| 228 | |
| 229 | if (znode->level != 0) { |
| 230 | int i; |
| 231 | const int n = zn->child_cnt; |
| 232 | |
| 233 | /* The children now have new parent */ |
| 234 | for (i = 0; i < n; i++) { |
| 235 | struct ubifs_zbranch *zbr = &zn->zbranch[i]; |
| 236 | |
| 237 | if (zbr->znode) |
| 238 | zbr->znode->parent = zn; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | atomic_long_inc(&c->dirty_zn_cnt); |
| 243 | return zn; |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * add_idx_dirt - add dirt due to a dirty znode. |
| 248 | * @c: UBIFS file-system description object |
| 249 | * @lnum: LEB number of index node |
| 250 | * @dirt: size of index node |
| 251 | * |
| 252 | * This function updates lprops dirty space and the new size of the index. |
| 253 | */ |
| 254 | static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt) |
| 255 | { |
| 256 | c->calc_idx_sz -= ALIGN(dirt, 8); |
| 257 | return ubifs_add_dirt(c, lnum, dirt); |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * dirty_cow_znode - ensure a znode is not being committed. |
| 262 | * @c: UBIFS file-system description object |
| 263 | * @zbr: branch of znode to check |
| 264 | * |
| 265 | * Returns dirtied znode on success or negative error code on failure. |
| 266 | */ |
| 267 | static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c, |
| 268 | struct ubifs_zbranch *zbr) |
| 269 | { |
| 270 | struct ubifs_znode *znode = zbr->znode; |
| 271 | struct ubifs_znode *zn; |
| 272 | int err; |
| 273 | |
Artem Bityutskiy | f42eed7 | 2011-05-30 14:45:30 +0300 | [diff] [blame] | 274 | if (!ubifs_zn_cow(znode)) { |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 275 | /* znode is not being committed */ |
| 276 | if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) { |
| 277 | atomic_long_inc(&c->dirty_zn_cnt); |
| 278 | atomic_long_dec(&c->clean_zn_cnt); |
| 279 | atomic_long_dec(&ubifs_clean_zn_cnt); |
| 280 | err = add_idx_dirt(c, zbr->lnum, zbr->len); |
| 281 | if (unlikely(err)) |
| 282 | return ERR_PTR(err); |
| 283 | } |
| 284 | return znode; |
| 285 | } |
| 286 | |
| 287 | zn = copy_znode(c, znode); |
Hirofumi Nakagawa | 8d47aef | 2008-08-21 17:16:40 +0300 | [diff] [blame] | 288 | if (IS_ERR(zn)) |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 289 | return zn; |
| 290 | |
| 291 | if (zbr->len) { |
| 292 | err = insert_old_idx(c, zbr->lnum, zbr->offs); |
| 293 | if (unlikely(err)) |
| 294 | return ERR_PTR(err); |
| 295 | err = add_idx_dirt(c, zbr->lnum, zbr->len); |
| 296 | } else |
| 297 | err = 0; |
| 298 | |
| 299 | zbr->znode = zn; |
| 300 | zbr->lnum = 0; |
| 301 | zbr->offs = 0; |
| 302 | zbr->len = 0; |
| 303 | |
| 304 | if (unlikely(err)) |
| 305 | return ERR_PTR(err); |
| 306 | return zn; |
| 307 | } |
| 308 | |
| 309 | /** |
| 310 | * lnc_add - add a leaf node to the leaf node cache. |
| 311 | * @c: UBIFS file-system description object |
| 312 | * @zbr: zbranch of leaf node |
| 313 | * @node: leaf node |
| 314 | * |
| 315 | * Leaf nodes are non-index nodes directory entry nodes or data nodes. The |
| 316 | * purpose of the leaf node cache is to save re-reading the same leaf node over |
| 317 | * and over again. Most things are cached by VFS, however the file system must |
| 318 | * cache directory entries for readdir and for resolving hash collisions. The |
| 319 | * present implementation of the leaf node cache is extremely simple, and |
| 320 | * allows for error returns that are not used but that may be needed if a more |
| 321 | * complex implementation is created. |
| 322 | * |
| 323 | * Note, this function does not add the @node object to LNC directly, but |
| 324 | * allocates a copy of the object and adds the copy to LNC. The reason for this |
| 325 | * is that @node has been allocated outside of the TNC subsystem and will be |
| 326 | * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC |
| 327 | * may be changed at any time, e.g. freed by the shrinker. |
| 328 | */ |
| 329 | static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
| 330 | const void *node) |
| 331 | { |
| 332 | int err; |
| 333 | void *lnc_node; |
| 334 | const struct ubifs_dent_node *dent = node; |
| 335 | |
| 336 | ubifs_assert(!zbr->leaf); |
| 337 | ubifs_assert(zbr->len != 0); |
| 338 | ubifs_assert(is_hash_key(c, &zbr->key)); |
| 339 | |
| 340 | err = ubifs_validate_entry(c, dent); |
| 341 | if (err) { |
| 342 | dbg_dump_stack(); |
| 343 | dbg_dump_node(c, dent); |
| 344 | return err; |
| 345 | } |
| 346 | |
Thomas Meyer | eaecf43 | 2011-11-18 00:00:52 +0100 | [diff] [blame] | 347 | lnc_node = kmemdup(node, zbr->len, GFP_NOFS); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 348 | if (!lnc_node) |
| 349 | /* We don't have to have the cache, so no error */ |
| 350 | return 0; |
| 351 | |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 352 | zbr->leaf = lnc_node; |
| 353 | return 0; |
| 354 | } |
| 355 | |
| 356 | /** |
| 357 | * lnc_add_directly - add a leaf node to the leaf-node-cache. |
| 358 | * @c: UBIFS file-system description object |
| 359 | * @zbr: zbranch of leaf node |
| 360 | * @node: leaf node |
| 361 | * |
| 362 | * This function is similar to 'lnc_add()', but it does not create a copy of |
| 363 | * @node but inserts @node to TNC directly. |
| 364 | */ |
| 365 | static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
| 366 | void *node) |
| 367 | { |
| 368 | int err; |
| 369 | |
| 370 | ubifs_assert(!zbr->leaf); |
| 371 | ubifs_assert(zbr->len != 0); |
| 372 | |
| 373 | err = ubifs_validate_entry(c, node); |
| 374 | if (err) { |
| 375 | dbg_dump_stack(); |
| 376 | dbg_dump_node(c, node); |
| 377 | return err; |
| 378 | } |
| 379 | |
| 380 | zbr->leaf = node; |
| 381 | return 0; |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * lnc_free - remove a leaf node from the leaf node cache. |
| 386 | * @zbr: zbranch of leaf node |
| 387 | * @node: leaf node |
| 388 | */ |
| 389 | static void lnc_free(struct ubifs_zbranch *zbr) |
| 390 | { |
| 391 | if (!zbr->leaf) |
| 392 | return; |
| 393 | kfree(zbr->leaf); |
| 394 | zbr->leaf = NULL; |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * tnc_read_node_nm - read a "hashed" leaf node. |
| 399 | * @c: UBIFS file-system description object |
| 400 | * @zbr: key and position of the node |
| 401 | * @node: node is returned here |
| 402 | * |
| 403 | * This function reads a "hashed" node defined by @zbr from the leaf node cache |
| 404 | * (in it is there) or from the hash media, in which case the node is also |
| 405 | * added to LNC. Returns zero in case of success or a negative negative error |
| 406 | * code in case of failure. |
| 407 | */ |
| 408 | static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
| 409 | void *node) |
| 410 | { |
| 411 | int err; |
| 412 | |
| 413 | ubifs_assert(is_hash_key(c, &zbr->key)); |
| 414 | |
| 415 | if (zbr->leaf) { |
| 416 | /* Read from the leaf node cache */ |
| 417 | ubifs_assert(zbr->len != 0); |
| 418 | memcpy(node, zbr->leaf, zbr->len); |
| 419 | return 0; |
| 420 | } |
| 421 | |
| 422 | err = ubifs_tnc_read_node(c, zbr, node); |
| 423 | if (err) |
| 424 | return err; |
| 425 | |
| 426 | /* Add the node to the leaf node cache */ |
| 427 | err = lnc_add(c, zbr, node); |
| 428 | return err; |
| 429 | } |
| 430 | |
| 431 | /** |
| 432 | * try_read_node - read a node if it is a node. |
| 433 | * @c: UBIFS file-system description object |
| 434 | * @buf: buffer to read to |
| 435 | * @type: node type |
| 436 | * @len: node length (not aligned) |
| 437 | * @lnum: LEB number of node to read |
| 438 | * @offs: offset of node to read |
| 439 | * |
| 440 | * This function tries to read a node of known type and length, checks it and |
| 441 | * stores it in @buf. This function returns %1 if a node is present and %0 if |
| 442 | * a node is not present. A negative error code is returned for I/O errors. |
| 443 | * This function performs that same function as ubifs_read_node except that |
| 444 | * it does not require that there is actually a node present and instead |
| 445 | * the return code indicates if a node was read. |
Artem Bityutskiy | 6f7ab6d | 2009-01-27 16:12:31 +0200 | [diff] [blame] | 446 | * |
| 447 | * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc |
| 448 | * is true (it is controlled by corresponding mount option). However, if |
Artem Bityutskiy | 18d1d7f | 2011-01-17 22:27:56 +0200 | [diff] [blame] | 449 | * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to |
| 450 | * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is |
| 451 | * because during mounting or re-mounting from R/O mode to R/W mode we may read |
| 452 | * journal nodes (when replying the journal or doing the recovery) and the |
| 453 | * journal nodes may potentially be corrupted, so checking is required. |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 454 | */ |
| 455 | static int try_read_node(const struct ubifs_info *c, void *buf, int type, |
| 456 | int len, int lnum, int offs) |
| 457 | { |
| 458 | int err, node_len; |
| 459 | struct ubifs_ch *ch = buf; |
| 460 | uint32_t crc, node_crc; |
| 461 | |
| 462 | dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len); |
| 463 | |
Artem Bityutskiy | d304820 | 2011-06-03 14:03:25 +0300 | [diff] [blame] | 464 | err = ubifs_leb_read(c, lnum, buf, offs, len, 1); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 465 | if (err) { |
| 466 | ubifs_err("cannot read node type %d from LEB %d:%d, error %d", |
| 467 | type, lnum, offs, err); |
| 468 | return err; |
| 469 | } |
| 470 | |
| 471 | if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) |
| 472 | return 0; |
| 473 | |
| 474 | if (ch->node_type != type) |
| 475 | return 0; |
| 476 | |
| 477 | node_len = le32_to_cpu(ch->len); |
| 478 | if (node_len != len) |
| 479 | return 0; |
| 480 | |
Artem Bityutskiy | 18d1d7f | 2011-01-17 22:27:56 +0200 | [diff] [blame] | 481 | if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting && |
| 482 | !c->remounting_rw) |
Artem Bityutskiy | 6f7ab6d | 2009-01-27 16:12:31 +0200 | [diff] [blame] | 483 | return 1; |
Adrian Hunter | 2953e73 | 2008-09-04 16:26:00 +0300 | [diff] [blame] | 484 | |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 485 | crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); |
| 486 | node_crc = le32_to_cpu(ch->crc); |
| 487 | if (crc != node_crc) |
| 488 | return 0; |
| 489 | |
| 490 | return 1; |
| 491 | } |
| 492 | |
| 493 | /** |
| 494 | * fallible_read_node - try to read a leaf node. |
| 495 | * @c: UBIFS file-system description object |
| 496 | * @key: key of node to read |
| 497 | * @zbr: position of node |
| 498 | * @node: node returned |
| 499 | * |
| 500 | * This function tries to read a node and returns %1 if the node is read, %0 |
| 501 | * if the node is not present, and a negative error code in the case of error. |
| 502 | */ |
| 503 | static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key, |
| 504 | struct ubifs_zbranch *zbr, void *node) |
| 505 | { |
| 506 | int ret; |
| 507 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 508 | dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 509 | |
| 510 | ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum, |
| 511 | zbr->offs); |
| 512 | if (ret == 1) { |
| 513 | union ubifs_key node_key; |
| 514 | struct ubifs_dent_node *dent = node; |
| 515 | |
| 516 | /* All nodes have key in the same place */ |
| 517 | key_read(c, &dent->key, &node_key); |
| 518 | if (keys_cmp(c, key, &node_key) != 0) |
| 519 | ret = 0; |
| 520 | } |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 521 | if (ret == 0 && c->replaying) |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 522 | dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ", |
| 523 | zbr->lnum, zbr->offs, zbr->len); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 524 | return ret; |
| 525 | } |
| 526 | |
| 527 | /** |
| 528 | * matches_name - determine if a direntry or xattr entry matches a given name. |
| 529 | * @c: UBIFS file-system description object |
| 530 | * @zbr: zbranch of dent |
| 531 | * @nm: name to match |
| 532 | * |
| 533 | * This function checks if xentry/direntry referred by zbranch @zbr matches name |
| 534 | * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by |
| 535 | * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case |
| 536 | * of failure, a negative error code is returned. |
| 537 | */ |
| 538 | static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
| 539 | const struct qstr *nm) |
| 540 | { |
| 541 | struct ubifs_dent_node *dent; |
| 542 | int nlen, err; |
| 543 | |
| 544 | /* If possible, match against the dent in the leaf node cache */ |
| 545 | if (!zbr->leaf) { |
| 546 | dent = kmalloc(zbr->len, GFP_NOFS); |
| 547 | if (!dent) |
| 548 | return -ENOMEM; |
| 549 | |
| 550 | err = ubifs_tnc_read_node(c, zbr, dent); |
| 551 | if (err) |
| 552 | goto out_free; |
| 553 | |
| 554 | /* Add the node to the leaf node cache */ |
| 555 | err = lnc_add_directly(c, zbr, dent); |
| 556 | if (err) |
| 557 | goto out_free; |
| 558 | } else |
| 559 | dent = zbr->leaf; |
| 560 | |
| 561 | nlen = le16_to_cpu(dent->nlen); |
| 562 | err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); |
| 563 | if (err == 0) { |
| 564 | if (nlen == nm->len) |
| 565 | return NAME_MATCHES; |
| 566 | else if (nlen < nm->len) |
| 567 | return NAME_LESS; |
| 568 | else |
| 569 | return NAME_GREATER; |
| 570 | } else if (err < 0) |
| 571 | return NAME_LESS; |
| 572 | else |
| 573 | return NAME_GREATER; |
| 574 | |
| 575 | out_free: |
| 576 | kfree(dent); |
| 577 | return err; |
| 578 | } |
| 579 | |
| 580 | /** |
| 581 | * get_znode - get a TNC znode that may not be loaded yet. |
| 582 | * @c: UBIFS file-system description object |
| 583 | * @znode: parent znode |
| 584 | * @n: znode branch slot number |
| 585 | * |
| 586 | * This function returns the znode or a negative error code. |
| 587 | */ |
| 588 | static struct ubifs_znode *get_znode(struct ubifs_info *c, |
| 589 | struct ubifs_znode *znode, int n) |
| 590 | { |
| 591 | struct ubifs_zbranch *zbr; |
| 592 | |
| 593 | zbr = &znode->zbranch[n]; |
| 594 | if (zbr->znode) |
| 595 | znode = zbr->znode; |
| 596 | else |
| 597 | znode = ubifs_load_znode(c, zbr, znode, n); |
| 598 | return znode; |
| 599 | } |
| 600 | |
| 601 | /** |
| 602 | * tnc_next - find next TNC entry. |
| 603 | * @c: UBIFS file-system description object |
| 604 | * @zn: znode is passed and returned here |
| 605 | * @n: znode branch slot number is passed and returned here |
| 606 | * |
| 607 | * This function returns %0 if the next TNC entry is found, %-ENOENT if there is |
| 608 | * no next entry, or a negative error code otherwise. |
| 609 | */ |
| 610 | static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n) |
| 611 | { |
| 612 | struct ubifs_znode *znode = *zn; |
| 613 | int nn = *n; |
| 614 | |
| 615 | nn += 1; |
| 616 | if (nn < znode->child_cnt) { |
| 617 | *n = nn; |
| 618 | return 0; |
| 619 | } |
| 620 | while (1) { |
| 621 | struct ubifs_znode *zp; |
| 622 | |
| 623 | zp = znode->parent; |
| 624 | if (!zp) |
| 625 | return -ENOENT; |
| 626 | nn = znode->iip + 1; |
| 627 | znode = zp; |
| 628 | if (nn < znode->child_cnt) { |
| 629 | znode = get_znode(c, znode, nn); |
| 630 | if (IS_ERR(znode)) |
| 631 | return PTR_ERR(znode); |
| 632 | while (znode->level != 0) { |
| 633 | znode = get_znode(c, znode, 0); |
| 634 | if (IS_ERR(znode)) |
| 635 | return PTR_ERR(znode); |
| 636 | } |
| 637 | nn = 0; |
| 638 | break; |
| 639 | } |
| 640 | } |
| 641 | *zn = znode; |
| 642 | *n = nn; |
| 643 | return 0; |
| 644 | } |
| 645 | |
| 646 | /** |
| 647 | * tnc_prev - find previous TNC entry. |
| 648 | * @c: UBIFS file-system description object |
| 649 | * @zn: znode is returned here |
| 650 | * @n: znode branch slot number is passed and returned here |
| 651 | * |
| 652 | * This function returns %0 if the previous TNC entry is found, %-ENOENT if |
| 653 | * there is no next entry, or a negative error code otherwise. |
| 654 | */ |
| 655 | static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n) |
| 656 | { |
| 657 | struct ubifs_znode *znode = *zn; |
| 658 | int nn = *n; |
| 659 | |
| 660 | if (nn > 0) { |
| 661 | *n = nn - 1; |
| 662 | return 0; |
| 663 | } |
| 664 | while (1) { |
| 665 | struct ubifs_znode *zp; |
| 666 | |
| 667 | zp = znode->parent; |
| 668 | if (!zp) |
| 669 | return -ENOENT; |
| 670 | nn = znode->iip - 1; |
| 671 | znode = zp; |
| 672 | if (nn >= 0) { |
| 673 | znode = get_znode(c, znode, nn); |
| 674 | if (IS_ERR(znode)) |
| 675 | return PTR_ERR(znode); |
| 676 | while (znode->level != 0) { |
| 677 | nn = znode->child_cnt - 1; |
| 678 | znode = get_znode(c, znode, nn); |
| 679 | if (IS_ERR(znode)) |
| 680 | return PTR_ERR(znode); |
| 681 | } |
| 682 | nn = znode->child_cnt - 1; |
| 683 | break; |
| 684 | } |
| 685 | } |
| 686 | *zn = znode; |
| 687 | *n = nn; |
| 688 | return 0; |
| 689 | } |
| 690 | |
| 691 | /** |
| 692 | * resolve_collision - resolve a collision. |
| 693 | * @c: UBIFS file-system description object |
| 694 | * @key: key of a directory or extended attribute entry |
| 695 | * @zn: znode is returned here |
| 696 | * @n: zbranch number is passed and returned here |
| 697 | * @nm: name of the entry |
| 698 | * |
| 699 | * This function is called for "hashed" keys to make sure that the found key |
| 700 | * really corresponds to the looked up node (directory or extended attribute |
| 701 | * entry). It returns %1 and sets @zn and @n if the collision is resolved. |
| 702 | * %0 is returned if @nm is not found and @zn and @n are set to the previous |
| 703 | * entry, i.e. to the entry after which @nm could follow if it were in TNC. |
| 704 | * This means that @n may be set to %-1 if the leftmost key in @zn is the |
| 705 | * previous one. A negative error code is returned on failures. |
| 706 | */ |
| 707 | static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key, |
| 708 | struct ubifs_znode **zn, int *n, |
| 709 | const struct qstr *nm) |
| 710 | { |
| 711 | int err; |
| 712 | |
| 713 | err = matches_name(c, &(*zn)->zbranch[*n], nm); |
| 714 | if (unlikely(err < 0)) |
| 715 | return err; |
| 716 | if (err == NAME_MATCHES) |
| 717 | return 1; |
| 718 | |
| 719 | if (err == NAME_GREATER) { |
| 720 | /* Look left */ |
| 721 | while (1) { |
| 722 | err = tnc_prev(c, zn, n); |
| 723 | if (err == -ENOENT) { |
| 724 | ubifs_assert(*n == 0); |
| 725 | *n = -1; |
| 726 | return 0; |
| 727 | } |
| 728 | if (err < 0) |
| 729 | return err; |
| 730 | if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { |
| 731 | /* |
| 732 | * We have found the branch after which we would |
| 733 | * like to insert, but inserting in this znode |
| 734 | * may still be wrong. Consider the following 3 |
| 735 | * znodes, in the case where we are resolving a |
| 736 | * collision with Key2. |
| 737 | * |
| 738 | * znode zp |
| 739 | * ---------------------- |
| 740 | * level 1 | Key0 | Key1 | |
| 741 | * ----------------------- |
| 742 | * | | |
| 743 | * znode za | | znode zb |
| 744 | * ------------ ------------ |
| 745 | * level 0 | Key0 | | Key2 | |
| 746 | * ------------ ------------ |
| 747 | * |
| 748 | * The lookup finds Key2 in znode zb. Lets say |
| 749 | * there is no match and the name is greater so |
| 750 | * we look left. When we find Key0, we end up |
| 751 | * here. If we return now, we will insert into |
| 752 | * znode za at slot n = 1. But that is invalid |
| 753 | * according to the parent's keys. Key2 must |
| 754 | * be inserted into znode zb. |
| 755 | * |
| 756 | * Note, this problem is not relevant for the |
| 757 | * case when we go right, because |
| 758 | * 'tnc_insert()' would correct the parent key. |
| 759 | */ |
| 760 | if (*n == (*zn)->child_cnt - 1) { |
| 761 | err = tnc_next(c, zn, n); |
| 762 | if (err) { |
| 763 | /* Should be impossible */ |
| 764 | ubifs_assert(0); |
| 765 | if (err == -ENOENT) |
| 766 | err = -EINVAL; |
| 767 | return err; |
| 768 | } |
| 769 | ubifs_assert(*n == 0); |
| 770 | *n = -1; |
| 771 | } |
| 772 | return 0; |
| 773 | } |
| 774 | err = matches_name(c, &(*zn)->zbranch[*n], nm); |
| 775 | if (err < 0) |
| 776 | return err; |
| 777 | if (err == NAME_LESS) |
| 778 | return 0; |
| 779 | if (err == NAME_MATCHES) |
| 780 | return 1; |
| 781 | ubifs_assert(err == NAME_GREATER); |
| 782 | } |
| 783 | } else { |
| 784 | int nn = *n; |
| 785 | struct ubifs_znode *znode = *zn; |
| 786 | |
| 787 | /* Look right */ |
| 788 | while (1) { |
| 789 | err = tnc_next(c, &znode, &nn); |
| 790 | if (err == -ENOENT) |
| 791 | return 0; |
| 792 | if (err < 0) |
| 793 | return err; |
| 794 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
| 795 | return 0; |
| 796 | err = matches_name(c, &znode->zbranch[nn], nm); |
| 797 | if (err < 0) |
| 798 | return err; |
| 799 | if (err == NAME_GREATER) |
| 800 | return 0; |
| 801 | *zn = znode; |
| 802 | *n = nn; |
| 803 | if (err == NAME_MATCHES) |
| 804 | return 1; |
| 805 | ubifs_assert(err == NAME_LESS); |
| 806 | } |
| 807 | } |
| 808 | } |
| 809 | |
| 810 | /** |
| 811 | * fallible_matches_name - determine if a dent matches a given name. |
| 812 | * @c: UBIFS file-system description object |
| 813 | * @zbr: zbranch of dent |
| 814 | * @nm: name to match |
| 815 | * |
| 816 | * This is a "fallible" version of 'matches_name()' function which does not |
| 817 | * panic if the direntry/xentry referred by @zbr does not exist on the media. |
| 818 | * |
| 819 | * This function checks if xentry/direntry referred by zbranch @zbr matches name |
| 820 | * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr |
| 821 | * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA |
| 822 | * if xentry/direntry referred by @zbr does not exist on the media. A negative |
| 823 | * error code is returned in case of failure. |
| 824 | */ |
| 825 | static int fallible_matches_name(struct ubifs_info *c, |
| 826 | struct ubifs_zbranch *zbr, |
| 827 | const struct qstr *nm) |
| 828 | { |
| 829 | struct ubifs_dent_node *dent; |
| 830 | int nlen, err; |
| 831 | |
| 832 | /* If possible, match against the dent in the leaf node cache */ |
| 833 | if (!zbr->leaf) { |
| 834 | dent = kmalloc(zbr->len, GFP_NOFS); |
| 835 | if (!dent) |
| 836 | return -ENOMEM; |
| 837 | |
| 838 | err = fallible_read_node(c, &zbr->key, zbr, dent); |
| 839 | if (err < 0) |
| 840 | goto out_free; |
| 841 | if (err == 0) { |
| 842 | /* The node was not present */ |
| 843 | err = NOT_ON_MEDIA; |
| 844 | goto out_free; |
| 845 | } |
| 846 | ubifs_assert(err == 1); |
| 847 | |
| 848 | err = lnc_add_directly(c, zbr, dent); |
| 849 | if (err) |
| 850 | goto out_free; |
| 851 | } else |
| 852 | dent = zbr->leaf; |
| 853 | |
| 854 | nlen = le16_to_cpu(dent->nlen); |
| 855 | err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); |
| 856 | if (err == 0) { |
| 857 | if (nlen == nm->len) |
| 858 | return NAME_MATCHES; |
| 859 | else if (nlen < nm->len) |
| 860 | return NAME_LESS; |
| 861 | else |
| 862 | return NAME_GREATER; |
| 863 | } else if (err < 0) |
| 864 | return NAME_LESS; |
| 865 | else |
| 866 | return NAME_GREATER; |
| 867 | |
| 868 | out_free: |
| 869 | kfree(dent); |
| 870 | return err; |
| 871 | } |
| 872 | |
| 873 | /** |
| 874 | * fallible_resolve_collision - resolve a collision even if nodes are missing. |
| 875 | * @c: UBIFS file-system description object |
| 876 | * @key: key |
| 877 | * @zn: znode is returned here |
| 878 | * @n: branch number is passed and returned here |
| 879 | * @nm: name of directory entry |
| 880 | * @adding: indicates caller is adding a key to the TNC |
| 881 | * |
| 882 | * This is a "fallible" version of the 'resolve_collision()' function which |
| 883 | * does not panic if one of the nodes referred to by TNC does not exist on the |
| 884 | * media. This may happen when replaying the journal if a deleted node was |
| 885 | * Garbage-collected and the commit was not done. A branch that refers to a node |
| 886 | * that is not present is called a dangling branch. The following are the return |
| 887 | * codes for this function: |
| 888 | * o if @nm was found, %1 is returned and @zn and @n are set to the found |
| 889 | * branch; |
| 890 | * o if we are @adding and @nm was not found, %0 is returned; |
| 891 | * o if we are not @adding and @nm was not found, but a dangling branch was |
| 892 | * found, then %1 is returned and @zn and @n are set to the dangling branch; |
| 893 | * o a negative error code is returned in case of failure. |
| 894 | */ |
| 895 | static int fallible_resolve_collision(struct ubifs_info *c, |
| 896 | const union ubifs_key *key, |
| 897 | struct ubifs_znode **zn, int *n, |
| 898 | const struct qstr *nm, int adding) |
| 899 | { |
| 900 | struct ubifs_znode *o_znode = NULL, *znode = *zn; |
| 901 | int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n; |
| 902 | |
| 903 | cmp = fallible_matches_name(c, &znode->zbranch[nn], nm); |
| 904 | if (unlikely(cmp < 0)) |
| 905 | return cmp; |
| 906 | if (cmp == NAME_MATCHES) |
| 907 | return 1; |
| 908 | if (cmp == NOT_ON_MEDIA) { |
| 909 | o_znode = znode; |
| 910 | o_n = nn; |
| 911 | /* |
| 912 | * We are unlucky and hit a dangling branch straight away. |
| 913 | * Now we do not really know where to go to find the needed |
| 914 | * branch - to the left or to the right. Well, let's try left. |
| 915 | */ |
| 916 | unsure = 1; |
| 917 | } else if (!adding) |
| 918 | unsure = 1; /* Remove a dangling branch wherever it is */ |
| 919 | |
| 920 | if (cmp == NAME_GREATER || unsure) { |
| 921 | /* Look left */ |
| 922 | while (1) { |
| 923 | err = tnc_prev(c, zn, n); |
| 924 | if (err == -ENOENT) { |
| 925 | ubifs_assert(*n == 0); |
| 926 | *n = -1; |
| 927 | break; |
| 928 | } |
| 929 | if (err < 0) |
| 930 | return err; |
| 931 | if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { |
| 932 | /* See comments in 'resolve_collision()' */ |
| 933 | if (*n == (*zn)->child_cnt - 1) { |
| 934 | err = tnc_next(c, zn, n); |
| 935 | if (err) { |
| 936 | /* Should be impossible */ |
| 937 | ubifs_assert(0); |
| 938 | if (err == -ENOENT) |
| 939 | err = -EINVAL; |
| 940 | return err; |
| 941 | } |
| 942 | ubifs_assert(*n == 0); |
| 943 | *n = -1; |
| 944 | } |
| 945 | break; |
| 946 | } |
| 947 | err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm); |
| 948 | if (err < 0) |
| 949 | return err; |
| 950 | if (err == NAME_MATCHES) |
| 951 | return 1; |
| 952 | if (err == NOT_ON_MEDIA) { |
| 953 | o_znode = *zn; |
| 954 | o_n = *n; |
| 955 | continue; |
| 956 | } |
| 957 | if (!adding) |
| 958 | continue; |
| 959 | if (err == NAME_LESS) |
| 960 | break; |
| 961 | else |
| 962 | unsure = 0; |
| 963 | } |
| 964 | } |
| 965 | |
| 966 | if (cmp == NAME_LESS || unsure) { |
| 967 | /* Look right */ |
| 968 | *zn = znode; |
| 969 | *n = nn; |
| 970 | while (1) { |
| 971 | err = tnc_next(c, &znode, &nn); |
| 972 | if (err == -ENOENT) |
| 973 | break; |
| 974 | if (err < 0) |
| 975 | return err; |
| 976 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
| 977 | break; |
| 978 | err = fallible_matches_name(c, &znode->zbranch[nn], nm); |
| 979 | if (err < 0) |
| 980 | return err; |
| 981 | if (err == NAME_GREATER) |
| 982 | break; |
| 983 | *zn = znode; |
| 984 | *n = nn; |
| 985 | if (err == NAME_MATCHES) |
| 986 | return 1; |
| 987 | if (err == NOT_ON_MEDIA) { |
| 988 | o_znode = znode; |
| 989 | o_n = nn; |
| 990 | } |
| 991 | } |
| 992 | } |
| 993 | |
| 994 | /* Never match a dangling branch when adding */ |
| 995 | if (adding || !o_znode) |
| 996 | return 0; |
| 997 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 998 | dbg_mntk(key, "dangling match LEB %d:%d len %d key ", |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 999 | o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs, |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1000 | o_znode->zbranch[o_n].len); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1001 | *zn = o_znode; |
| 1002 | *n = o_n; |
| 1003 | return 1; |
| 1004 | } |
| 1005 | |
| 1006 | /** |
| 1007 | * matches_position - determine if a zbranch matches a given position. |
| 1008 | * @zbr: zbranch of dent |
| 1009 | * @lnum: LEB number of dent to match |
| 1010 | * @offs: offset of dent to match |
| 1011 | * |
| 1012 | * This function returns %1 if @lnum:@offs matches, and %0 otherwise. |
| 1013 | */ |
| 1014 | static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs) |
| 1015 | { |
| 1016 | if (zbr->lnum == lnum && zbr->offs == offs) |
| 1017 | return 1; |
| 1018 | else |
| 1019 | return 0; |
| 1020 | } |
| 1021 | |
| 1022 | /** |
| 1023 | * resolve_collision_directly - resolve a collision directly. |
| 1024 | * @c: UBIFS file-system description object |
| 1025 | * @key: key of directory entry |
| 1026 | * @zn: znode is passed and returned here |
| 1027 | * @n: zbranch number is passed and returned here |
| 1028 | * @lnum: LEB number of dent node to match |
| 1029 | * @offs: offset of dent node to match |
| 1030 | * |
| 1031 | * This function is used for "hashed" keys to make sure the found directory or |
| 1032 | * extended attribute entry node is what was looked for. It is used when the |
| 1033 | * flash address of the right node is known (@lnum:@offs) which makes it much |
| 1034 | * easier to resolve collisions (no need to read entries and match full |
| 1035 | * names). This function returns %1 and sets @zn and @n if the collision is |
| 1036 | * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the |
| 1037 | * previous directory entry. Otherwise a negative error code is returned. |
| 1038 | */ |
| 1039 | static int resolve_collision_directly(struct ubifs_info *c, |
| 1040 | const union ubifs_key *key, |
| 1041 | struct ubifs_znode **zn, int *n, |
| 1042 | int lnum, int offs) |
| 1043 | { |
| 1044 | struct ubifs_znode *znode; |
| 1045 | int nn, err; |
| 1046 | |
| 1047 | znode = *zn; |
| 1048 | nn = *n; |
| 1049 | if (matches_position(&znode->zbranch[nn], lnum, offs)) |
| 1050 | return 1; |
| 1051 | |
| 1052 | /* Look left */ |
| 1053 | while (1) { |
| 1054 | err = tnc_prev(c, &znode, &nn); |
| 1055 | if (err == -ENOENT) |
| 1056 | break; |
| 1057 | if (err < 0) |
| 1058 | return err; |
| 1059 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
| 1060 | break; |
| 1061 | if (matches_position(&znode->zbranch[nn], lnum, offs)) { |
| 1062 | *zn = znode; |
| 1063 | *n = nn; |
| 1064 | return 1; |
| 1065 | } |
| 1066 | } |
| 1067 | |
| 1068 | /* Look right */ |
| 1069 | znode = *zn; |
| 1070 | nn = *n; |
| 1071 | while (1) { |
| 1072 | err = tnc_next(c, &znode, &nn); |
| 1073 | if (err == -ENOENT) |
| 1074 | return 0; |
| 1075 | if (err < 0) |
| 1076 | return err; |
| 1077 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
| 1078 | return 0; |
| 1079 | *zn = znode; |
| 1080 | *n = nn; |
| 1081 | if (matches_position(&znode->zbranch[nn], lnum, offs)) |
| 1082 | return 1; |
| 1083 | } |
| 1084 | } |
| 1085 | |
| 1086 | /** |
| 1087 | * dirty_cow_bottom_up - dirty a znode and its ancestors. |
| 1088 | * @c: UBIFS file-system description object |
| 1089 | * @znode: znode to dirty |
| 1090 | * |
| 1091 | * If we do not have a unique key that resides in a znode, then we cannot |
| 1092 | * dirty that znode from the top down (i.e. by using lookup_level0_dirty) |
| 1093 | * This function records the path back to the last dirty ancestor, and then |
| 1094 | * dirties the znodes on that path. |
| 1095 | */ |
| 1096 | static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c, |
| 1097 | struct ubifs_znode *znode) |
| 1098 | { |
| 1099 | struct ubifs_znode *zp; |
| 1100 | int *path = c->bottom_up_buf, p = 0; |
| 1101 | |
| 1102 | ubifs_assert(c->zroot.znode); |
| 1103 | ubifs_assert(znode); |
| 1104 | if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) { |
| 1105 | kfree(c->bottom_up_buf); |
| 1106 | c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int), |
| 1107 | GFP_NOFS); |
| 1108 | if (!c->bottom_up_buf) |
| 1109 | return ERR_PTR(-ENOMEM); |
| 1110 | path = c->bottom_up_buf; |
| 1111 | } |
| 1112 | if (c->zroot.znode->level) { |
| 1113 | /* Go up until parent is dirty */ |
| 1114 | while (1) { |
| 1115 | int n; |
| 1116 | |
| 1117 | zp = znode->parent; |
| 1118 | if (!zp) |
| 1119 | break; |
| 1120 | n = znode->iip; |
| 1121 | ubifs_assert(p < c->zroot.znode->level); |
| 1122 | path[p++] = n; |
| 1123 | if (!zp->cnext && ubifs_zn_dirty(znode)) |
| 1124 | break; |
| 1125 | znode = zp; |
| 1126 | } |
| 1127 | } |
| 1128 | |
| 1129 | /* Come back down, dirtying as we go */ |
| 1130 | while (1) { |
| 1131 | struct ubifs_zbranch *zbr; |
| 1132 | |
| 1133 | zp = znode->parent; |
| 1134 | if (zp) { |
| 1135 | ubifs_assert(path[p - 1] >= 0); |
| 1136 | ubifs_assert(path[p - 1] < zp->child_cnt); |
| 1137 | zbr = &zp->zbranch[path[--p]]; |
| 1138 | znode = dirty_cow_znode(c, zbr); |
| 1139 | } else { |
| 1140 | ubifs_assert(znode == c->zroot.znode); |
| 1141 | znode = dirty_cow_znode(c, &c->zroot); |
| 1142 | } |
Hirofumi Nakagawa | 8d47aef | 2008-08-21 17:16:40 +0300 | [diff] [blame] | 1143 | if (IS_ERR(znode) || !p) |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1144 | break; |
| 1145 | ubifs_assert(path[p - 1] >= 0); |
| 1146 | ubifs_assert(path[p - 1] < znode->child_cnt); |
| 1147 | znode = znode->zbranch[path[p - 1]].znode; |
| 1148 | } |
| 1149 | |
| 1150 | return znode; |
| 1151 | } |
| 1152 | |
| 1153 | /** |
| 1154 | * ubifs_lookup_level0 - search for zero-level znode. |
| 1155 | * @c: UBIFS file-system description object |
| 1156 | * @key: key to lookup |
| 1157 | * @zn: znode is returned here |
| 1158 | * @n: znode branch slot number is returned here |
| 1159 | * |
| 1160 | * This function looks up the TNC tree and search for zero-level znode which |
| 1161 | * refers key @key. The found zero-level znode is returned in @zn. There are 3 |
| 1162 | * cases: |
| 1163 | * o exact match, i.e. the found zero-level znode contains key @key, then %1 |
| 1164 | * is returned and slot number of the matched branch is stored in @n; |
| 1165 | * o not exact match, which means that zero-level znode does not contain |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 1166 | * @key, then %0 is returned and slot number of the closest branch is stored |
| 1167 | * in @n; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1168 | * o @key is so small that it is even less than the lowest key of the |
| 1169 | * leftmost zero-level node, then %0 is returned and %0 is stored in @n. |
| 1170 | * |
| 1171 | * Note, when the TNC tree is traversed, some znodes may be absent, then this |
| 1172 | * function reads corresponding indexing nodes and inserts them to TNC. In |
| 1173 | * case of failure, a negative error code is returned. |
| 1174 | */ |
| 1175 | int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key, |
| 1176 | struct ubifs_znode **zn, int *n) |
| 1177 | { |
| 1178 | int err, exact; |
| 1179 | struct ubifs_znode *znode; |
| 1180 | unsigned long time = get_seconds(); |
| 1181 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1182 | dbg_tnck(key, "search key "); |
Artem Bityutskiy | ba2f48f | 2010-08-22 07:10:12 +0300 | [diff] [blame] | 1183 | ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1184 | |
| 1185 | znode = c->zroot.znode; |
| 1186 | if (unlikely(!znode)) { |
| 1187 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
| 1188 | if (IS_ERR(znode)) |
| 1189 | return PTR_ERR(znode); |
| 1190 | } |
| 1191 | |
| 1192 | znode->time = time; |
| 1193 | |
| 1194 | while (1) { |
| 1195 | struct ubifs_zbranch *zbr; |
| 1196 | |
| 1197 | exact = ubifs_search_zbranch(c, znode, key, n); |
| 1198 | |
| 1199 | if (znode->level == 0) |
| 1200 | break; |
| 1201 | |
| 1202 | if (*n < 0) |
| 1203 | *n = 0; |
| 1204 | zbr = &znode->zbranch[*n]; |
| 1205 | |
| 1206 | if (zbr->znode) { |
| 1207 | znode->time = time; |
| 1208 | znode = zbr->znode; |
| 1209 | continue; |
| 1210 | } |
| 1211 | |
| 1212 | /* znode is not in TNC cache, load it from the media */ |
| 1213 | znode = ubifs_load_znode(c, zbr, znode, *n); |
| 1214 | if (IS_ERR(znode)) |
| 1215 | return PTR_ERR(znode); |
| 1216 | } |
| 1217 | |
| 1218 | *zn = znode; |
| 1219 | if (exact || !is_hash_key(c, key) || *n != -1) { |
| 1220 | dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); |
| 1221 | return exact; |
| 1222 | } |
| 1223 | |
| 1224 | /* |
| 1225 | * Here is a tricky place. We have not found the key and this is a |
| 1226 | * "hashed" key, which may collide. The rest of the code deals with |
| 1227 | * situations like this: |
| 1228 | * |
| 1229 | * | 3 | 5 | |
| 1230 | * / \ |
| 1231 | * | 3 | 5 | | 6 | 7 | (x) |
| 1232 | * |
| 1233 | * Or more a complex example: |
| 1234 | * |
| 1235 | * | 1 | 5 | |
| 1236 | * / \ |
| 1237 | * | 1 | 3 | | 5 | 8 | |
| 1238 | * \ / |
| 1239 | * | 5 | 5 | | 6 | 7 | (x) |
| 1240 | * |
| 1241 | * In the examples, if we are looking for key "5", we may reach nodes |
| 1242 | * marked with "(x)". In this case what we have do is to look at the |
| 1243 | * left and see if there is "5" key there. If there is, we have to |
| 1244 | * return it. |
| 1245 | * |
| 1246 | * Note, this whole situation is possible because we allow to have |
| 1247 | * elements which are equivalent to the next key in the parent in the |
| 1248 | * children of current znode. For example, this happens if we split a |
| 1249 | * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something |
| 1250 | * like this: |
| 1251 | * | 3 | 5 | |
| 1252 | * / \ |
| 1253 | * | 3 | 5 | | 5 | 6 | 7 | |
| 1254 | * ^ |
| 1255 | * And this becomes what is at the first "picture" after key "5" marked |
| 1256 | * with "^" is removed. What could be done is we could prohibit |
| 1257 | * splitting in the middle of the colliding sequence. Also, when |
| 1258 | * removing the leftmost key, we would have to correct the key of the |
| 1259 | * parent node, which would introduce additional complications. Namely, |
Artem Bityutskiy | 7d4e9cc | 2009-03-20 19:11:12 +0200 | [diff] [blame] | 1260 | * if we changed the leftmost key of the parent znode, the garbage |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1261 | * collector would be unable to find it (GC is doing this when GC'ing |
| 1262 | * indexing LEBs). Although we already have an additional RB-tree where |
| 1263 | * we save such changed znodes (see 'ins_clr_old_idx_znode()') until |
| 1264 | * after the commit. But anyway, this does not look easy to implement |
| 1265 | * so we did not try this. |
| 1266 | */ |
| 1267 | err = tnc_prev(c, &znode, n); |
| 1268 | if (err == -ENOENT) { |
| 1269 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
| 1270 | *n = -1; |
| 1271 | return 0; |
| 1272 | } |
| 1273 | if (unlikely(err < 0)) |
| 1274 | return err; |
| 1275 | if (keys_cmp(c, key, &znode->zbranch[*n].key)) { |
| 1276 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
| 1277 | *n = -1; |
| 1278 | return 0; |
| 1279 | } |
| 1280 | |
| 1281 | dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); |
| 1282 | *zn = znode; |
| 1283 | return 1; |
| 1284 | } |
| 1285 | |
| 1286 | /** |
| 1287 | * lookup_level0_dirty - search for zero-level znode dirtying. |
| 1288 | * @c: UBIFS file-system description object |
| 1289 | * @key: key to lookup |
| 1290 | * @zn: znode is returned here |
| 1291 | * @n: znode branch slot number is returned here |
| 1292 | * |
| 1293 | * This function looks up the TNC tree and search for zero-level znode which |
| 1294 | * refers key @key. The found zero-level znode is returned in @zn. There are 3 |
| 1295 | * cases: |
| 1296 | * o exact match, i.e. the found zero-level znode contains key @key, then %1 |
| 1297 | * is returned and slot number of the matched branch is stored in @n; |
| 1298 | * o not exact match, which means that zero-level znode does not contain @key |
| 1299 | * then %0 is returned and slot number of the closed branch is stored in |
| 1300 | * @n; |
| 1301 | * o @key is so small that it is even less than the lowest key of the |
| 1302 | * leftmost zero-level node, then %0 is returned and %-1 is stored in @n. |
| 1303 | * |
| 1304 | * Additionally all znodes in the path from the root to the located zero-level |
| 1305 | * znode are marked as dirty. |
| 1306 | * |
| 1307 | * Note, when the TNC tree is traversed, some znodes may be absent, then this |
| 1308 | * function reads corresponding indexing nodes and inserts them to TNC. In |
| 1309 | * case of failure, a negative error code is returned. |
| 1310 | */ |
| 1311 | static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key, |
| 1312 | struct ubifs_znode **zn, int *n) |
| 1313 | { |
| 1314 | int err, exact; |
| 1315 | struct ubifs_znode *znode; |
| 1316 | unsigned long time = get_seconds(); |
| 1317 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1318 | dbg_tnck(key, "search and dirty key "); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1319 | |
| 1320 | znode = c->zroot.znode; |
| 1321 | if (unlikely(!znode)) { |
| 1322 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
| 1323 | if (IS_ERR(znode)) |
| 1324 | return PTR_ERR(znode); |
| 1325 | } |
| 1326 | |
| 1327 | znode = dirty_cow_znode(c, &c->zroot); |
| 1328 | if (IS_ERR(znode)) |
| 1329 | return PTR_ERR(znode); |
| 1330 | |
| 1331 | znode->time = time; |
| 1332 | |
| 1333 | while (1) { |
| 1334 | struct ubifs_zbranch *zbr; |
| 1335 | |
| 1336 | exact = ubifs_search_zbranch(c, znode, key, n); |
| 1337 | |
| 1338 | if (znode->level == 0) |
| 1339 | break; |
| 1340 | |
| 1341 | if (*n < 0) |
| 1342 | *n = 0; |
| 1343 | zbr = &znode->zbranch[*n]; |
| 1344 | |
| 1345 | if (zbr->znode) { |
| 1346 | znode->time = time; |
| 1347 | znode = dirty_cow_znode(c, zbr); |
| 1348 | if (IS_ERR(znode)) |
| 1349 | return PTR_ERR(znode); |
| 1350 | continue; |
| 1351 | } |
| 1352 | |
| 1353 | /* znode is not in TNC cache, load it from the media */ |
| 1354 | znode = ubifs_load_znode(c, zbr, znode, *n); |
| 1355 | if (IS_ERR(znode)) |
| 1356 | return PTR_ERR(znode); |
| 1357 | znode = dirty_cow_znode(c, zbr); |
| 1358 | if (IS_ERR(znode)) |
| 1359 | return PTR_ERR(znode); |
| 1360 | } |
| 1361 | |
| 1362 | *zn = znode; |
| 1363 | if (exact || !is_hash_key(c, key) || *n != -1) { |
| 1364 | dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); |
| 1365 | return exact; |
| 1366 | } |
| 1367 | |
| 1368 | /* |
| 1369 | * See huge comment at 'lookup_level0_dirty()' what is the rest of the |
| 1370 | * code. |
| 1371 | */ |
| 1372 | err = tnc_prev(c, &znode, n); |
| 1373 | if (err == -ENOENT) { |
| 1374 | *n = -1; |
| 1375 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
| 1376 | return 0; |
| 1377 | } |
| 1378 | if (unlikely(err < 0)) |
| 1379 | return err; |
| 1380 | if (keys_cmp(c, key, &znode->zbranch[*n].key)) { |
| 1381 | *n = -1; |
| 1382 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
| 1383 | return 0; |
| 1384 | } |
| 1385 | |
| 1386 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
| 1387 | znode = dirty_cow_bottom_up(c, znode); |
| 1388 | if (IS_ERR(znode)) |
| 1389 | return PTR_ERR(znode); |
| 1390 | } |
| 1391 | |
| 1392 | dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); |
| 1393 | *zn = znode; |
| 1394 | return 1; |
| 1395 | } |
| 1396 | |
| 1397 | /** |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1398 | * maybe_leb_gced - determine if a LEB may have been garbage collected. |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1399 | * @c: UBIFS file-system description object |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1400 | * @lnum: LEB number |
| 1401 | * @gc_seq1: garbage collection sequence number |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1402 | * |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1403 | * This function determines if @lnum may have been garbage collected since |
| 1404 | * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise |
| 1405 | * %0 is returned. |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1406 | */ |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1407 | static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1) |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1408 | { |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1409 | int gc_seq2, gced_lnum; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1410 | |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1411 | gced_lnum = c->gced_lnum; |
| 1412 | smp_rmb(); |
| 1413 | gc_seq2 = c->gc_seq; |
| 1414 | /* Same seq means no GC */ |
| 1415 | if (gc_seq1 == gc_seq2) |
| 1416 | return 0; |
| 1417 | /* Different by more than 1 means we don't know */ |
| 1418 | if (gc_seq1 + 1 != gc_seq2) |
| 1419 | return 1; |
| 1420 | /* |
| 1421 | * We have seen the sequence number has increased by 1. Now we need to |
| 1422 | * be sure we read the right LEB number, so read it again. |
| 1423 | */ |
| 1424 | smp_rmb(); |
| 1425 | if (gced_lnum != c->gced_lnum) |
| 1426 | return 1; |
| 1427 | /* Finally we can check lnum */ |
| 1428 | if (gced_lnum == lnum) |
| 1429 | return 1; |
| 1430 | return 0; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1431 | } |
| 1432 | |
| 1433 | /** |
| 1434 | * ubifs_tnc_locate - look up a file-system node and return it and its location. |
| 1435 | * @c: UBIFS file-system description object |
| 1436 | * @key: node key to lookup |
| 1437 | * @node: the node is returned here |
| 1438 | * @lnum: LEB number is returned here |
| 1439 | * @offs: offset is returned here |
| 1440 | * |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 1441 | * This function looks up and reads node with key @key. The caller has to make |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1442 | * sure the @node buffer is large enough to fit the node. Returns zero in case |
| 1443 | * of success, %-ENOENT if the node was not found, and a negative error code in |
| 1444 | * case of failure. The node location can be returned in @lnum and @offs. |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1445 | */ |
| 1446 | int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key, |
| 1447 | void *node, int *lnum, int *offs) |
| 1448 | { |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1449 | int found, n, err, safely = 0, gc_seq1; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1450 | struct ubifs_znode *znode; |
| 1451 | struct ubifs_zbranch zbr, *zt; |
| 1452 | |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1453 | again: |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1454 | mutex_lock(&c->tnc_mutex); |
| 1455 | found = ubifs_lookup_level0(c, key, &znode, &n); |
| 1456 | if (!found) { |
| 1457 | err = -ENOENT; |
| 1458 | goto out; |
| 1459 | } else if (found < 0) { |
| 1460 | err = found; |
| 1461 | goto out; |
| 1462 | } |
| 1463 | zt = &znode->zbranch[n]; |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1464 | if (lnum) { |
| 1465 | *lnum = zt->lnum; |
| 1466 | *offs = zt->offs; |
| 1467 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1468 | if (is_hash_key(c, key)) { |
| 1469 | /* |
| 1470 | * In this case the leaf node cache gets used, so we pass the |
| 1471 | * address of the zbranch and keep the mutex locked |
| 1472 | */ |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1473 | err = tnc_read_node_nm(c, zt, node); |
| 1474 | goto out; |
| 1475 | } |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1476 | if (safely) { |
| 1477 | err = ubifs_tnc_read_node(c, zt, node); |
| 1478 | goto out; |
| 1479 | } |
| 1480 | /* Drop the TNC mutex prematurely and race with garbage collection */ |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1481 | zbr = znode->zbranch[n]; |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1482 | gc_seq1 = c->gc_seq; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1483 | mutex_unlock(&c->tnc_mutex); |
| 1484 | |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1485 | if (ubifs_get_wbuf(c, zbr.lnum)) { |
| 1486 | /* We do not GC journal heads */ |
| 1487 | err = ubifs_tnc_read_node(c, &zbr, node); |
| 1488 | return err; |
| 1489 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1490 | |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1491 | err = fallible_read_node(c, key, &zbr, node); |
Adrian Hunter | 6dcfac4 | 2008-09-12 12:27:47 +0300 | [diff] [blame] | 1492 | if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) { |
Adrian Hunter | 601c0bc | 2008-08-22 14:23:35 +0300 | [diff] [blame] | 1493 | /* |
| 1494 | * The node may have been GC'ed out from under us so try again |
| 1495 | * while keeping the TNC mutex locked. |
| 1496 | */ |
| 1497 | safely = 1; |
| 1498 | goto again; |
| 1499 | } |
| 1500 | return 0; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1501 | |
| 1502 | out: |
| 1503 | mutex_unlock(&c->tnc_mutex); |
| 1504 | return err; |
| 1505 | } |
| 1506 | |
| 1507 | /** |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1508 | * ubifs_tnc_get_bu_keys - lookup keys for bulk-read. |
| 1509 | * @c: UBIFS file-system description object |
| 1510 | * @bu: bulk-read parameters and results |
| 1511 | * |
| 1512 | * Lookup consecutive data node keys for the same inode that reside |
Artem Bityutskiy | 6c0c42c | 2008-11-18 20:20:05 +0200 | [diff] [blame] | 1513 | * consecutively in the same LEB. This function returns zero in case of success |
| 1514 | * and a negative error code in case of failure. |
| 1515 | * |
| 1516 | * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function |
| 1517 | * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares |
Artem Bityutskiy | 6f7ab6d | 2009-01-27 16:12:31 +0200 | [diff] [blame] | 1518 | * maximum possible amount of nodes for bulk-read. |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1519 | */ |
| 1520 | int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu) |
| 1521 | { |
| 1522 | int n, err = 0, lnum = -1, uninitialized_var(offs); |
| 1523 | int uninitialized_var(len); |
| 1524 | unsigned int block = key_block(c, &bu->key); |
| 1525 | struct ubifs_znode *znode; |
| 1526 | |
| 1527 | bu->cnt = 0; |
| 1528 | bu->blk_cnt = 0; |
| 1529 | bu->eof = 0; |
| 1530 | |
| 1531 | mutex_lock(&c->tnc_mutex); |
| 1532 | /* Find first key */ |
| 1533 | err = ubifs_lookup_level0(c, &bu->key, &znode, &n); |
| 1534 | if (err < 0) |
| 1535 | goto out; |
| 1536 | if (err) { |
| 1537 | /* Key found */ |
| 1538 | len = znode->zbranch[n].len; |
| 1539 | /* The buffer must be big enough for at least 1 node */ |
| 1540 | if (len > bu->buf_len) { |
| 1541 | err = -EINVAL; |
| 1542 | goto out; |
| 1543 | } |
| 1544 | /* Add this key */ |
| 1545 | bu->zbranch[bu->cnt++] = znode->zbranch[n]; |
| 1546 | bu->blk_cnt += 1; |
| 1547 | lnum = znode->zbranch[n].lnum; |
| 1548 | offs = ALIGN(znode->zbranch[n].offs + len, 8); |
| 1549 | } |
| 1550 | while (1) { |
| 1551 | struct ubifs_zbranch *zbr; |
| 1552 | union ubifs_key *key; |
| 1553 | unsigned int next_block; |
| 1554 | |
| 1555 | /* Find next key */ |
| 1556 | err = tnc_next(c, &znode, &n); |
| 1557 | if (err) |
| 1558 | goto out; |
| 1559 | zbr = &znode->zbranch[n]; |
| 1560 | key = &zbr->key; |
| 1561 | /* See if there is another data key for this file */ |
| 1562 | if (key_inum(c, key) != key_inum(c, &bu->key) || |
| 1563 | key_type(c, key) != UBIFS_DATA_KEY) { |
| 1564 | err = -ENOENT; |
| 1565 | goto out; |
| 1566 | } |
| 1567 | if (lnum < 0) { |
| 1568 | /* First key found */ |
| 1569 | lnum = zbr->lnum; |
| 1570 | offs = ALIGN(zbr->offs + zbr->len, 8); |
| 1571 | len = zbr->len; |
| 1572 | if (len > bu->buf_len) { |
| 1573 | err = -EINVAL; |
| 1574 | goto out; |
| 1575 | } |
| 1576 | } else { |
| 1577 | /* |
| 1578 | * The data nodes must be in consecutive positions in |
| 1579 | * the same LEB. |
| 1580 | */ |
| 1581 | if (zbr->lnum != lnum || zbr->offs != offs) |
| 1582 | goto out; |
| 1583 | offs += ALIGN(zbr->len, 8); |
| 1584 | len = ALIGN(len, 8) + zbr->len; |
| 1585 | /* Must not exceed buffer length */ |
| 1586 | if (len > bu->buf_len) |
| 1587 | goto out; |
| 1588 | } |
| 1589 | /* Allow for holes */ |
| 1590 | next_block = key_block(c, key); |
| 1591 | bu->blk_cnt += (next_block - block - 1); |
| 1592 | if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) |
| 1593 | goto out; |
| 1594 | block = next_block; |
| 1595 | /* Add this key */ |
| 1596 | bu->zbranch[bu->cnt++] = *zbr; |
| 1597 | bu->blk_cnt += 1; |
| 1598 | /* See if we have room for more */ |
| 1599 | if (bu->cnt >= UBIFS_MAX_BULK_READ) |
| 1600 | goto out; |
| 1601 | if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) |
| 1602 | goto out; |
| 1603 | } |
| 1604 | out: |
| 1605 | if (err == -ENOENT) { |
| 1606 | bu->eof = 1; |
| 1607 | err = 0; |
| 1608 | } |
| 1609 | bu->gc_seq = c->gc_seq; |
| 1610 | mutex_unlock(&c->tnc_mutex); |
| 1611 | if (err) |
| 1612 | return err; |
| 1613 | /* |
| 1614 | * An enormous hole could cause bulk-read to encompass too many |
| 1615 | * page cache pages, so limit the number here. |
| 1616 | */ |
Adrian Hunter | 63c300b | 2008-09-17 12:11:13 +0300 | [diff] [blame] | 1617 | if (bu->blk_cnt > UBIFS_MAX_BULK_READ) |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1618 | bu->blk_cnt = UBIFS_MAX_BULK_READ; |
| 1619 | /* |
| 1620 | * Ensure that bulk-read covers a whole number of page cache |
| 1621 | * pages. |
| 1622 | */ |
| 1623 | if (UBIFS_BLOCKS_PER_PAGE == 1 || |
| 1624 | !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1))) |
| 1625 | return 0; |
| 1626 | if (bu->eof) { |
| 1627 | /* At the end of file we can round up */ |
| 1628 | bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1; |
| 1629 | return 0; |
| 1630 | } |
| 1631 | /* Exclude data nodes that do not make up a whole page cache page */ |
| 1632 | block = key_block(c, &bu->key) + bu->blk_cnt; |
| 1633 | block &= ~(UBIFS_BLOCKS_PER_PAGE - 1); |
| 1634 | while (bu->cnt) { |
| 1635 | if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block) |
| 1636 | break; |
| 1637 | bu->cnt -= 1; |
| 1638 | } |
| 1639 | return 0; |
| 1640 | } |
| 1641 | |
| 1642 | /** |
| 1643 | * read_wbuf - bulk-read from a LEB with a wbuf. |
| 1644 | * @wbuf: wbuf that may overlap the read |
| 1645 | * @buf: buffer into which to read |
| 1646 | * @len: read length |
| 1647 | * @lnum: LEB number from which to read |
| 1648 | * @offs: offset from which to read |
| 1649 | * |
| 1650 | * This functions returns %0 on success or a negative error code on failure. |
| 1651 | */ |
| 1652 | static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum, |
| 1653 | int offs) |
| 1654 | { |
| 1655 | const struct ubifs_info *c = wbuf->c; |
| 1656 | int rlen, overlap; |
| 1657 | |
| 1658 | dbg_io("LEB %d:%d, length %d", lnum, offs, len); |
| 1659 | ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| 1660 | ubifs_assert(!(offs & 7) && offs < c->leb_size); |
| 1661 | ubifs_assert(offs + len <= c->leb_size); |
| 1662 | |
| 1663 | spin_lock(&wbuf->lock); |
| 1664 | overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs); |
| 1665 | if (!overlap) { |
| 1666 | /* We may safely unlock the write-buffer and read the data */ |
| 1667 | spin_unlock(&wbuf->lock); |
Artem Bityutskiy | d304820 | 2011-06-03 14:03:25 +0300 | [diff] [blame] | 1668 | return ubifs_leb_read(c, lnum, buf, offs, len, 0); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1669 | } |
| 1670 | |
| 1671 | /* Don't read under wbuf */ |
| 1672 | rlen = wbuf->offs - offs; |
| 1673 | if (rlen < 0) |
| 1674 | rlen = 0; |
| 1675 | |
| 1676 | /* Copy the rest from the write-buffer */ |
| 1677 | memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen); |
| 1678 | spin_unlock(&wbuf->lock); |
| 1679 | |
| 1680 | if (rlen > 0) |
| 1681 | /* Read everything that goes before write-buffer */ |
Artem Bityutskiy | d304820 | 2011-06-03 14:03:25 +0300 | [diff] [blame] | 1682 | return ubifs_leb_read(c, lnum, buf, offs, rlen, 0); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1683 | |
| 1684 | return 0; |
| 1685 | } |
| 1686 | |
| 1687 | /** |
| 1688 | * validate_data_node - validate data nodes for bulk-read. |
| 1689 | * @c: UBIFS file-system description object |
| 1690 | * @buf: buffer containing data node to validate |
| 1691 | * @zbr: zbranch of data node to validate |
| 1692 | * |
| 1693 | * This functions returns %0 on success or a negative error code on failure. |
| 1694 | */ |
| 1695 | static int validate_data_node(struct ubifs_info *c, void *buf, |
| 1696 | struct ubifs_zbranch *zbr) |
| 1697 | { |
| 1698 | union ubifs_key key1; |
| 1699 | struct ubifs_ch *ch = buf; |
| 1700 | int err, len; |
| 1701 | |
| 1702 | if (ch->node_type != UBIFS_DATA_NODE) { |
| 1703 | ubifs_err("bad node type (%d but expected %d)", |
| 1704 | ch->node_type, UBIFS_DATA_NODE); |
| 1705 | goto out_err; |
| 1706 | } |
| 1707 | |
Adrian Hunter | 2953e73 | 2008-09-04 16:26:00 +0300 | [diff] [blame] | 1708 | err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1709 | if (err) { |
| 1710 | ubifs_err("expected node type %d", UBIFS_DATA_NODE); |
| 1711 | goto out; |
| 1712 | } |
| 1713 | |
| 1714 | len = le32_to_cpu(ch->len); |
| 1715 | if (len != zbr->len) { |
| 1716 | ubifs_err("bad node length %d, expected %d", len, zbr->len); |
| 1717 | goto out_err; |
| 1718 | } |
| 1719 | |
| 1720 | /* Make sure the key of the read node is correct */ |
| 1721 | key_read(c, buf + UBIFS_KEY_OFFSET, &key1); |
| 1722 | if (!keys_eq(c, &zbr->key, &key1)) { |
| 1723 | ubifs_err("bad key in node at LEB %d:%d", |
| 1724 | zbr->lnum, zbr->offs); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1725 | dbg_tnck(&zbr->key, "looked for key "); |
| 1726 | dbg_tnck(&key1, "found node's key "); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1727 | goto out_err; |
| 1728 | } |
| 1729 | |
| 1730 | return 0; |
| 1731 | |
| 1732 | out_err: |
| 1733 | err = -EINVAL; |
| 1734 | out: |
| 1735 | ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs); |
| 1736 | dbg_dump_node(c, buf); |
| 1737 | dbg_dump_stack(); |
| 1738 | return err; |
| 1739 | } |
| 1740 | |
| 1741 | /** |
| 1742 | * ubifs_tnc_bulk_read - read a number of data nodes in one go. |
| 1743 | * @c: UBIFS file-system description object |
| 1744 | * @bu: bulk-read parameters and results |
| 1745 | * |
| 1746 | * This functions reads and validates the data nodes that were identified by the |
| 1747 | * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success, |
| 1748 | * -EAGAIN to indicate a race with GC, or another negative error code on |
| 1749 | * failure. |
| 1750 | */ |
| 1751 | int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu) |
| 1752 | { |
| 1753 | int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i; |
| 1754 | struct ubifs_wbuf *wbuf; |
| 1755 | void *buf; |
| 1756 | |
| 1757 | len = bu->zbranch[bu->cnt - 1].offs; |
| 1758 | len += bu->zbranch[bu->cnt - 1].len - offs; |
| 1759 | if (len > bu->buf_len) { |
| 1760 | ubifs_err("buffer too small %d vs %d", bu->buf_len, len); |
| 1761 | return -EINVAL; |
| 1762 | } |
| 1763 | |
| 1764 | /* Do the read */ |
| 1765 | wbuf = ubifs_get_wbuf(c, lnum); |
| 1766 | if (wbuf) |
| 1767 | err = read_wbuf(wbuf, bu->buf, len, lnum, offs); |
| 1768 | else |
Artem Bityutskiy | d304820 | 2011-06-03 14:03:25 +0300 | [diff] [blame] | 1769 | err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1770 | |
| 1771 | /* Check for a race with GC */ |
| 1772 | if (maybe_leb_gced(c, lnum, bu->gc_seq)) |
| 1773 | return -EAGAIN; |
| 1774 | |
| 1775 | if (err && err != -EBADMSG) { |
| 1776 | ubifs_err("failed to read from LEB %d:%d, error %d", |
| 1777 | lnum, offs, err); |
| 1778 | dbg_dump_stack(); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1779 | dbg_tnck(&bu->key, "key "); |
Adrian Hunter | 4793e7c | 2008-09-02 16:29:46 +0300 | [diff] [blame] | 1780 | return err; |
| 1781 | } |
| 1782 | |
| 1783 | /* Validate the nodes read */ |
| 1784 | buf = bu->buf; |
| 1785 | for (i = 0; i < bu->cnt; i++) { |
| 1786 | err = validate_data_node(c, buf, &bu->zbranch[i]); |
| 1787 | if (err) |
| 1788 | return err; |
| 1789 | buf = buf + ALIGN(bu->zbranch[i].len, 8); |
| 1790 | } |
| 1791 | |
| 1792 | return 0; |
| 1793 | } |
| 1794 | |
| 1795 | /** |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1796 | * do_lookup_nm- look up a "hashed" node. |
| 1797 | * @c: UBIFS file-system description object |
| 1798 | * @key: node key to lookup |
| 1799 | * @node: the node is returned here |
| 1800 | * @nm: node name |
| 1801 | * |
| 1802 | * This function look up and reads a node which contains name hash in the key. |
| 1803 | * Since the hash may have collisions, there may be many nodes with the same |
| 1804 | * key, so we have to sequentially look to all of them until the needed one is |
| 1805 | * found. This function returns zero in case of success, %-ENOENT if the node |
| 1806 | * was not found, and a negative error code in case of failure. |
| 1807 | */ |
| 1808 | static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key, |
| 1809 | void *node, const struct qstr *nm) |
| 1810 | { |
| 1811 | int found, n, err; |
| 1812 | struct ubifs_znode *znode; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1813 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1814 | dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1815 | mutex_lock(&c->tnc_mutex); |
| 1816 | found = ubifs_lookup_level0(c, key, &znode, &n); |
| 1817 | if (!found) { |
| 1818 | err = -ENOENT; |
| 1819 | goto out_unlock; |
| 1820 | } else if (found < 0) { |
| 1821 | err = found; |
| 1822 | goto out_unlock; |
| 1823 | } |
| 1824 | |
| 1825 | ubifs_assert(n >= 0); |
| 1826 | |
| 1827 | err = resolve_collision(c, key, &znode, &n, nm); |
| 1828 | dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n); |
| 1829 | if (unlikely(err < 0)) |
| 1830 | goto out_unlock; |
| 1831 | if (err == 0) { |
| 1832 | err = -ENOENT; |
| 1833 | goto out_unlock; |
| 1834 | } |
| 1835 | |
Adrian Hunter | 761e29f | 2008-08-20 16:32:40 +0300 | [diff] [blame] | 1836 | err = tnc_read_node_nm(c, &znode->zbranch[n], node); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1837 | |
| 1838 | out_unlock: |
| 1839 | mutex_unlock(&c->tnc_mutex); |
| 1840 | return err; |
| 1841 | } |
| 1842 | |
| 1843 | /** |
| 1844 | * ubifs_tnc_lookup_nm - look up a "hashed" node. |
| 1845 | * @c: UBIFS file-system description object |
| 1846 | * @key: node key to lookup |
| 1847 | * @node: the node is returned here |
| 1848 | * @nm: node name |
| 1849 | * |
| 1850 | * This function look up and reads a node which contains name hash in the key. |
| 1851 | * Since the hash may have collisions, there may be many nodes with the same |
| 1852 | * key, so we have to sequentially look to all of them until the needed one is |
| 1853 | * found. This function returns zero in case of success, %-ENOENT if the node |
| 1854 | * was not found, and a negative error code in case of failure. |
| 1855 | */ |
| 1856 | int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key, |
| 1857 | void *node, const struct qstr *nm) |
| 1858 | { |
| 1859 | int err, len; |
| 1860 | const struct ubifs_dent_node *dent = node; |
| 1861 | |
| 1862 | /* |
| 1863 | * We assume that in most of the cases there are no name collisions and |
| 1864 | * 'ubifs_tnc_lookup()' returns us the right direntry. |
| 1865 | */ |
| 1866 | err = ubifs_tnc_lookup(c, key, node); |
| 1867 | if (err) |
| 1868 | return err; |
| 1869 | |
| 1870 | len = le16_to_cpu(dent->nlen); |
| 1871 | if (nm->len == len && !memcmp(dent->name, nm->name, len)) |
| 1872 | return 0; |
| 1873 | |
| 1874 | /* |
| 1875 | * Unluckily, there are hash collisions and we have to iterate over |
| 1876 | * them look at each direntry with colliding name hash sequentially. |
| 1877 | */ |
| 1878 | return do_lookup_nm(c, key, node, nm); |
| 1879 | } |
| 1880 | |
| 1881 | /** |
| 1882 | * correct_parent_keys - correct parent znodes' keys. |
| 1883 | * @c: UBIFS file-system description object |
| 1884 | * @znode: znode to correct parent znodes for |
| 1885 | * |
| 1886 | * This is a helper function for 'tnc_insert()'. When the key of the leftmost |
| 1887 | * zbranch changes, keys of parent znodes have to be corrected. This helper |
| 1888 | * function is called in such situations and corrects the keys if needed. |
| 1889 | */ |
| 1890 | static void correct_parent_keys(const struct ubifs_info *c, |
| 1891 | struct ubifs_znode *znode) |
| 1892 | { |
| 1893 | union ubifs_key *key, *key1; |
| 1894 | |
| 1895 | ubifs_assert(znode->parent); |
| 1896 | ubifs_assert(znode->iip == 0); |
| 1897 | |
| 1898 | key = &znode->zbranch[0].key; |
| 1899 | key1 = &znode->parent->zbranch[0].key; |
| 1900 | |
| 1901 | while (keys_cmp(c, key, key1) < 0) { |
| 1902 | key_copy(c, key, key1); |
| 1903 | znode = znode->parent; |
| 1904 | znode->alt = 1; |
| 1905 | if (!znode->parent || znode->iip) |
| 1906 | break; |
| 1907 | key1 = &znode->parent->zbranch[0].key; |
| 1908 | } |
| 1909 | } |
| 1910 | |
| 1911 | /** |
| 1912 | * insert_zbranch - insert a zbranch into a znode. |
| 1913 | * @znode: znode into which to insert |
| 1914 | * @zbr: zbranch to insert |
| 1915 | * @n: slot number to insert to |
| 1916 | * |
| 1917 | * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in |
| 1918 | * znode's array of zbranches and keeps zbranches consolidated, so when a new |
| 1919 | * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th |
| 1920 | * slot, zbranches starting from @n have to be moved right. |
| 1921 | */ |
| 1922 | static void insert_zbranch(struct ubifs_znode *znode, |
| 1923 | const struct ubifs_zbranch *zbr, int n) |
| 1924 | { |
| 1925 | int i; |
| 1926 | |
| 1927 | ubifs_assert(ubifs_zn_dirty(znode)); |
| 1928 | |
| 1929 | if (znode->level) { |
| 1930 | for (i = znode->child_cnt; i > n; i--) { |
| 1931 | znode->zbranch[i] = znode->zbranch[i - 1]; |
| 1932 | if (znode->zbranch[i].znode) |
| 1933 | znode->zbranch[i].znode->iip = i; |
| 1934 | } |
| 1935 | if (zbr->znode) |
| 1936 | zbr->znode->iip = n; |
| 1937 | } else |
| 1938 | for (i = znode->child_cnt; i > n; i--) |
| 1939 | znode->zbranch[i] = znode->zbranch[i - 1]; |
| 1940 | |
| 1941 | znode->zbranch[n] = *zbr; |
| 1942 | znode->child_cnt += 1; |
| 1943 | |
| 1944 | /* |
| 1945 | * After inserting at slot zero, the lower bound of the key range of |
| 1946 | * this znode may have changed. If this znode is subsequently split |
| 1947 | * then the upper bound of the key range may change, and furthermore |
| 1948 | * it could change to be lower than the original lower bound. If that |
| 1949 | * happens, then it will no longer be possible to find this znode in the |
| 1950 | * TNC using the key from the index node on flash. That is bad because |
| 1951 | * if it is not found, we will assume it is obsolete and may overwrite |
| 1952 | * it. Then if there is an unclean unmount, we will start using the |
| 1953 | * old index which will be broken. |
| 1954 | * |
| 1955 | * So we first mark znodes that have insertions at slot zero, and then |
| 1956 | * if they are split we add their lnum/offs to the old_idx tree. |
| 1957 | */ |
| 1958 | if (n == 0) |
| 1959 | znode->alt = 1; |
| 1960 | } |
| 1961 | |
| 1962 | /** |
| 1963 | * tnc_insert - insert a node into TNC. |
| 1964 | * @c: UBIFS file-system description object |
| 1965 | * @znode: znode to insert into |
| 1966 | * @zbr: branch to insert |
| 1967 | * @n: slot number to insert new zbranch to |
| 1968 | * |
| 1969 | * This function inserts a new node described by @zbr into znode @znode. If |
| 1970 | * znode does not have a free slot for new zbranch, it is split. Parent znodes |
| 1971 | * are splat as well if needed. Returns zero in case of success or a negative |
| 1972 | * error code in case of failure. |
| 1973 | */ |
| 1974 | static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, |
| 1975 | struct ubifs_zbranch *zbr, int n) |
| 1976 | { |
| 1977 | struct ubifs_znode *zn, *zi, *zp; |
| 1978 | int i, keep, move, appending = 0; |
Adrian Hunter | 2242c68 | 2008-09-05 11:56:05 +0300 | [diff] [blame] | 1979 | union ubifs_key *key = &zbr->key, *key1; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1980 | |
| 1981 | ubifs_assert(n >= 0 && n <= c->fanout); |
| 1982 | |
| 1983 | /* Implement naive insert for now */ |
| 1984 | again: |
| 1985 | zp = znode->parent; |
| 1986 | if (znode->child_cnt < c->fanout) { |
| 1987 | ubifs_assert(n != c->fanout); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 1988 | dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 1989 | |
| 1990 | insert_zbranch(znode, zbr, n); |
| 1991 | |
| 1992 | /* Ensure parent's key is correct */ |
| 1993 | if (n == 0 && zp && znode->iip == 0) |
| 1994 | correct_parent_keys(c, znode); |
| 1995 | |
| 1996 | return 0; |
| 1997 | } |
| 1998 | |
| 1999 | /* |
| 2000 | * Unfortunately, @znode does not have more empty slots and we have to |
| 2001 | * split it. |
| 2002 | */ |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2003 | dbg_tnck(key, "splitting level %d, key ", znode->level); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2004 | |
| 2005 | if (znode->alt) |
| 2006 | /* |
| 2007 | * We can no longer be sure of finding this znode by key, so we |
| 2008 | * record it in the old_idx tree. |
| 2009 | */ |
| 2010 | ins_clr_old_idx_znode(c, znode); |
| 2011 | |
| 2012 | zn = kzalloc(c->max_znode_sz, GFP_NOFS); |
| 2013 | if (!zn) |
| 2014 | return -ENOMEM; |
| 2015 | zn->parent = zp; |
| 2016 | zn->level = znode->level; |
| 2017 | |
| 2018 | /* Decide where to split */ |
Adrian Hunter | 2242c68 | 2008-09-05 11:56:05 +0300 | [diff] [blame] | 2019 | if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) { |
| 2020 | /* Try not to split consecutive data keys */ |
| 2021 | if (n == c->fanout) { |
| 2022 | key1 = &znode->zbranch[n - 1].key; |
| 2023 | if (key_inum(c, key1) == key_inum(c, key) && |
| 2024 | key_type(c, key1) == UBIFS_DATA_KEY) |
| 2025 | appending = 1; |
| 2026 | } else |
| 2027 | goto check_split; |
| 2028 | } else if (appending && n != c->fanout) { |
| 2029 | /* Try not to split consecutive data keys */ |
| 2030 | appending = 0; |
| 2031 | check_split: |
| 2032 | if (n >= (c->fanout + 1) / 2) { |
| 2033 | key1 = &znode->zbranch[0].key; |
| 2034 | if (key_inum(c, key1) == key_inum(c, key) && |
| 2035 | key_type(c, key1) == UBIFS_DATA_KEY) { |
| 2036 | key1 = &znode->zbranch[n].key; |
| 2037 | if (key_inum(c, key1) != key_inum(c, key) || |
| 2038 | key_type(c, key1) != UBIFS_DATA_KEY) { |
| 2039 | keep = n; |
| 2040 | move = c->fanout - keep; |
| 2041 | zi = znode; |
| 2042 | goto do_split; |
| 2043 | } |
| 2044 | } |
| 2045 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2046 | } |
| 2047 | |
| 2048 | if (appending) { |
| 2049 | keep = c->fanout; |
| 2050 | move = 0; |
| 2051 | } else { |
| 2052 | keep = (c->fanout + 1) / 2; |
| 2053 | move = c->fanout - keep; |
| 2054 | } |
| 2055 | |
| 2056 | /* |
| 2057 | * Although we don't at present, we could look at the neighbors and see |
| 2058 | * if we can move some zbranches there. |
| 2059 | */ |
| 2060 | |
| 2061 | if (n < keep) { |
| 2062 | /* Insert into existing znode */ |
| 2063 | zi = znode; |
| 2064 | move += 1; |
| 2065 | keep -= 1; |
| 2066 | } else { |
| 2067 | /* Insert into new znode */ |
| 2068 | zi = zn; |
| 2069 | n -= keep; |
| 2070 | /* Re-parent */ |
| 2071 | if (zn->level != 0) |
| 2072 | zbr->znode->parent = zn; |
| 2073 | } |
| 2074 | |
Adrian Hunter | 2242c68 | 2008-09-05 11:56:05 +0300 | [diff] [blame] | 2075 | do_split: |
| 2076 | |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2077 | __set_bit(DIRTY_ZNODE, &zn->flags); |
| 2078 | atomic_long_inc(&c->dirty_zn_cnt); |
| 2079 | |
| 2080 | zn->child_cnt = move; |
| 2081 | znode->child_cnt = keep; |
| 2082 | |
| 2083 | dbg_tnc("moving %d, keeping %d", move, keep); |
| 2084 | |
| 2085 | /* Move zbranch */ |
| 2086 | for (i = 0; i < move; i++) { |
| 2087 | zn->zbranch[i] = znode->zbranch[keep + i]; |
| 2088 | /* Re-parent */ |
| 2089 | if (zn->level != 0) |
| 2090 | if (zn->zbranch[i].znode) { |
| 2091 | zn->zbranch[i].znode->parent = zn; |
| 2092 | zn->zbranch[i].znode->iip = i; |
| 2093 | } |
| 2094 | } |
| 2095 | |
| 2096 | /* Insert new key and branch */ |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2097 | dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2098 | |
| 2099 | insert_zbranch(zi, zbr, n); |
| 2100 | |
| 2101 | /* Insert new znode (produced by spitting) into the parent */ |
| 2102 | if (zp) { |
Adrian Hunter | 2242c68 | 2008-09-05 11:56:05 +0300 | [diff] [blame] | 2103 | if (n == 0 && zi == znode && znode->iip == 0) |
| 2104 | correct_parent_keys(c, znode); |
| 2105 | |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2106 | /* Locate insertion point */ |
| 2107 | n = znode->iip + 1; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2108 | |
| 2109 | /* Tail recursion */ |
| 2110 | zbr->key = zn->zbranch[0].key; |
| 2111 | zbr->znode = zn; |
| 2112 | zbr->lnum = 0; |
| 2113 | zbr->offs = 0; |
| 2114 | zbr->len = 0; |
| 2115 | znode = zp; |
| 2116 | |
| 2117 | goto again; |
| 2118 | } |
| 2119 | |
| 2120 | /* We have to split root znode */ |
| 2121 | dbg_tnc("creating new zroot at level %d", znode->level + 1); |
| 2122 | |
| 2123 | zi = kzalloc(c->max_znode_sz, GFP_NOFS); |
| 2124 | if (!zi) |
| 2125 | return -ENOMEM; |
| 2126 | |
| 2127 | zi->child_cnt = 2; |
| 2128 | zi->level = znode->level + 1; |
| 2129 | |
| 2130 | __set_bit(DIRTY_ZNODE, &zi->flags); |
| 2131 | atomic_long_inc(&c->dirty_zn_cnt); |
| 2132 | |
| 2133 | zi->zbranch[0].key = znode->zbranch[0].key; |
| 2134 | zi->zbranch[0].znode = znode; |
| 2135 | zi->zbranch[0].lnum = c->zroot.lnum; |
| 2136 | zi->zbranch[0].offs = c->zroot.offs; |
| 2137 | zi->zbranch[0].len = c->zroot.len; |
| 2138 | zi->zbranch[1].key = zn->zbranch[0].key; |
| 2139 | zi->zbranch[1].znode = zn; |
| 2140 | |
| 2141 | c->zroot.lnum = 0; |
| 2142 | c->zroot.offs = 0; |
| 2143 | c->zroot.len = 0; |
| 2144 | c->zroot.znode = zi; |
| 2145 | |
| 2146 | zn->parent = zi; |
| 2147 | zn->iip = 1; |
| 2148 | znode->parent = zi; |
| 2149 | znode->iip = 0; |
| 2150 | |
| 2151 | return 0; |
| 2152 | } |
| 2153 | |
| 2154 | /** |
| 2155 | * ubifs_tnc_add - add a node to TNC. |
| 2156 | * @c: UBIFS file-system description object |
| 2157 | * @key: key to add |
| 2158 | * @lnum: LEB number of node |
| 2159 | * @offs: node offset |
| 2160 | * @len: node length |
| 2161 | * |
| 2162 | * This function adds a node with key @key to TNC. The node may be new or it may |
| 2163 | * obsolete some existing one. Returns %0 on success or negative error code on |
| 2164 | * failure. |
| 2165 | */ |
| 2166 | int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum, |
| 2167 | int offs, int len) |
| 2168 | { |
| 2169 | int found, n, err = 0; |
| 2170 | struct ubifs_znode *znode; |
| 2171 | |
| 2172 | mutex_lock(&c->tnc_mutex); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2173 | dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2174 | found = lookup_level0_dirty(c, key, &znode, &n); |
| 2175 | if (!found) { |
| 2176 | struct ubifs_zbranch zbr; |
| 2177 | |
| 2178 | zbr.znode = NULL; |
| 2179 | zbr.lnum = lnum; |
| 2180 | zbr.offs = offs; |
| 2181 | zbr.len = len; |
| 2182 | key_copy(c, key, &zbr.key); |
| 2183 | err = tnc_insert(c, znode, &zbr, n + 1); |
| 2184 | } else if (found == 1) { |
| 2185 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
| 2186 | |
| 2187 | lnc_free(zbr); |
| 2188 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
| 2189 | zbr->lnum = lnum; |
| 2190 | zbr->offs = offs; |
| 2191 | zbr->len = len; |
| 2192 | } else |
| 2193 | err = found; |
| 2194 | if (!err) |
| 2195 | err = dbg_check_tnc(c, 0); |
| 2196 | mutex_unlock(&c->tnc_mutex); |
| 2197 | |
| 2198 | return err; |
| 2199 | } |
| 2200 | |
| 2201 | /** |
| 2202 | * ubifs_tnc_replace - replace a node in the TNC only if the old node is found. |
| 2203 | * @c: UBIFS file-system description object |
| 2204 | * @key: key to add |
| 2205 | * @old_lnum: LEB number of old node |
| 2206 | * @old_offs: old node offset |
| 2207 | * @lnum: LEB number of node |
| 2208 | * @offs: node offset |
| 2209 | * @len: node length |
| 2210 | * |
| 2211 | * This function replaces a node with key @key in the TNC only if the old node |
| 2212 | * is found. This function is called by garbage collection when node are moved. |
| 2213 | * Returns %0 on success or negative error code on failure. |
| 2214 | */ |
| 2215 | int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key, |
| 2216 | int old_lnum, int old_offs, int lnum, int offs, int len) |
| 2217 | { |
| 2218 | int found, n, err = 0; |
| 2219 | struct ubifs_znode *znode; |
| 2220 | |
| 2221 | mutex_lock(&c->tnc_mutex); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2222 | dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum, |
| 2223 | old_offs, lnum, offs, len); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2224 | found = lookup_level0_dirty(c, key, &znode, &n); |
| 2225 | if (found < 0) { |
| 2226 | err = found; |
| 2227 | goto out_unlock; |
| 2228 | } |
| 2229 | |
| 2230 | if (found == 1) { |
| 2231 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
| 2232 | |
| 2233 | found = 0; |
| 2234 | if (zbr->lnum == old_lnum && zbr->offs == old_offs) { |
| 2235 | lnc_free(zbr); |
| 2236 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
| 2237 | if (err) |
| 2238 | goto out_unlock; |
| 2239 | zbr->lnum = lnum; |
| 2240 | zbr->offs = offs; |
| 2241 | zbr->len = len; |
| 2242 | found = 1; |
| 2243 | } else if (is_hash_key(c, key)) { |
| 2244 | found = resolve_collision_directly(c, key, &znode, &n, |
| 2245 | old_lnum, old_offs); |
| 2246 | dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d", |
| 2247 | found, znode, n, old_lnum, old_offs); |
| 2248 | if (found < 0) { |
| 2249 | err = found; |
| 2250 | goto out_unlock; |
| 2251 | } |
| 2252 | |
| 2253 | if (found) { |
| 2254 | /* Ensure the znode is dirtied */ |
| 2255 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
Artem Bityutskiy | f92b982 | 2008-12-28 11:34:26 +0200 | [diff] [blame] | 2256 | znode = dirty_cow_bottom_up(c, znode); |
| 2257 | if (IS_ERR(znode)) { |
| 2258 | err = PTR_ERR(znode); |
| 2259 | goto out_unlock; |
| 2260 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2261 | } |
| 2262 | zbr = &znode->zbranch[n]; |
| 2263 | lnc_free(zbr); |
| 2264 | err = ubifs_add_dirt(c, zbr->lnum, |
| 2265 | zbr->len); |
| 2266 | if (err) |
| 2267 | goto out_unlock; |
| 2268 | zbr->lnum = lnum; |
| 2269 | zbr->offs = offs; |
| 2270 | zbr->len = len; |
| 2271 | } |
| 2272 | } |
| 2273 | } |
| 2274 | |
| 2275 | if (!found) |
| 2276 | err = ubifs_add_dirt(c, lnum, len); |
| 2277 | |
| 2278 | if (!err) |
| 2279 | err = dbg_check_tnc(c, 0); |
| 2280 | |
| 2281 | out_unlock: |
| 2282 | mutex_unlock(&c->tnc_mutex); |
| 2283 | return err; |
| 2284 | } |
| 2285 | |
| 2286 | /** |
| 2287 | * ubifs_tnc_add_nm - add a "hashed" node to TNC. |
| 2288 | * @c: UBIFS file-system description object |
| 2289 | * @key: key to add |
| 2290 | * @lnum: LEB number of node |
| 2291 | * @offs: node offset |
| 2292 | * @len: node length |
| 2293 | * @nm: node name |
| 2294 | * |
| 2295 | * This is the same as 'ubifs_tnc_add()' but it should be used with keys which |
| 2296 | * may have collisions, like directory entry keys. |
| 2297 | */ |
| 2298 | int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key, |
| 2299 | int lnum, int offs, int len, const struct qstr *nm) |
| 2300 | { |
| 2301 | int found, n, err = 0; |
| 2302 | struct ubifs_znode *znode; |
| 2303 | |
| 2304 | mutex_lock(&c->tnc_mutex); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2305 | dbg_tnck(key, "LEB %d:%d, name '%.*s', key ", |
| 2306 | lnum, offs, nm->len, nm->name); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2307 | found = lookup_level0_dirty(c, key, &znode, &n); |
| 2308 | if (found < 0) { |
| 2309 | err = found; |
| 2310 | goto out_unlock; |
| 2311 | } |
| 2312 | |
| 2313 | if (found == 1) { |
| 2314 | if (c->replaying) |
| 2315 | found = fallible_resolve_collision(c, key, &znode, &n, |
| 2316 | nm, 1); |
| 2317 | else |
| 2318 | found = resolve_collision(c, key, &znode, &n, nm); |
| 2319 | dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n); |
| 2320 | if (found < 0) { |
| 2321 | err = found; |
| 2322 | goto out_unlock; |
| 2323 | } |
| 2324 | |
| 2325 | /* Ensure the znode is dirtied */ |
| 2326 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
Artem Bityutskiy | f92b982 | 2008-12-28 11:34:26 +0200 | [diff] [blame] | 2327 | znode = dirty_cow_bottom_up(c, znode); |
| 2328 | if (IS_ERR(znode)) { |
| 2329 | err = PTR_ERR(znode); |
| 2330 | goto out_unlock; |
| 2331 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2332 | } |
| 2333 | |
| 2334 | if (found == 1) { |
| 2335 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
| 2336 | |
| 2337 | lnc_free(zbr); |
| 2338 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
| 2339 | zbr->lnum = lnum; |
| 2340 | zbr->offs = offs; |
| 2341 | zbr->len = len; |
| 2342 | goto out_unlock; |
| 2343 | } |
| 2344 | } |
| 2345 | |
| 2346 | if (!found) { |
| 2347 | struct ubifs_zbranch zbr; |
| 2348 | |
| 2349 | zbr.znode = NULL; |
| 2350 | zbr.lnum = lnum; |
| 2351 | zbr.offs = offs; |
| 2352 | zbr.len = len; |
| 2353 | key_copy(c, key, &zbr.key); |
| 2354 | err = tnc_insert(c, znode, &zbr, n + 1); |
| 2355 | if (err) |
| 2356 | goto out_unlock; |
| 2357 | if (c->replaying) { |
| 2358 | /* |
| 2359 | * We did not find it in the index so there may be a |
| 2360 | * dangling branch still in the index. So we remove it |
| 2361 | * by passing 'ubifs_tnc_remove_nm()' the same key but |
| 2362 | * an unmatchable name. |
| 2363 | */ |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame^] | 2364 | struct qstr noname = { .name = "" }; |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2365 | |
| 2366 | err = dbg_check_tnc(c, 0); |
| 2367 | mutex_unlock(&c->tnc_mutex); |
| 2368 | if (err) |
| 2369 | return err; |
| 2370 | return ubifs_tnc_remove_nm(c, key, &noname); |
| 2371 | } |
| 2372 | } |
| 2373 | |
| 2374 | out_unlock: |
| 2375 | if (!err) |
| 2376 | err = dbg_check_tnc(c, 0); |
| 2377 | mutex_unlock(&c->tnc_mutex); |
| 2378 | return err; |
| 2379 | } |
| 2380 | |
| 2381 | /** |
| 2382 | * tnc_delete - delete a znode form TNC. |
| 2383 | * @c: UBIFS file-system description object |
| 2384 | * @znode: znode to delete from |
| 2385 | * @n: zbranch slot number to delete |
| 2386 | * |
| 2387 | * This function deletes a leaf node from @n-th slot of @znode. Returns zero in |
| 2388 | * case of success and a negative error code in case of failure. |
| 2389 | */ |
| 2390 | static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n) |
| 2391 | { |
| 2392 | struct ubifs_zbranch *zbr; |
| 2393 | struct ubifs_znode *zp; |
| 2394 | int i, err; |
| 2395 | |
| 2396 | /* Delete without merge for now */ |
| 2397 | ubifs_assert(znode->level == 0); |
| 2398 | ubifs_assert(n >= 0 && n < c->fanout); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2399 | dbg_tnck(&znode->zbranch[n].key, "deleting key "); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2400 | |
| 2401 | zbr = &znode->zbranch[n]; |
| 2402 | lnc_free(zbr); |
| 2403 | |
| 2404 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
| 2405 | if (err) { |
| 2406 | dbg_dump_znode(c, znode); |
| 2407 | return err; |
| 2408 | } |
| 2409 | |
| 2410 | /* We do not "gap" zbranch slots */ |
| 2411 | for (i = n; i < znode->child_cnt - 1; i++) |
| 2412 | znode->zbranch[i] = znode->zbranch[i + 1]; |
| 2413 | znode->child_cnt -= 1; |
| 2414 | |
| 2415 | if (znode->child_cnt > 0) |
| 2416 | return 0; |
| 2417 | |
| 2418 | /* |
| 2419 | * This was the last zbranch, we have to delete this znode from the |
| 2420 | * parent. |
| 2421 | */ |
| 2422 | |
| 2423 | do { |
Artem Bityutskiy | f42eed7 | 2011-05-30 14:45:30 +0300 | [diff] [blame] | 2424 | ubifs_assert(!ubifs_zn_obsolete(znode)); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2425 | ubifs_assert(ubifs_zn_dirty(znode)); |
| 2426 | |
| 2427 | zp = znode->parent; |
| 2428 | n = znode->iip; |
| 2429 | |
| 2430 | atomic_long_dec(&c->dirty_zn_cnt); |
| 2431 | |
| 2432 | err = insert_old_idx_znode(c, znode); |
| 2433 | if (err) |
| 2434 | return err; |
| 2435 | |
| 2436 | if (znode->cnext) { |
| 2437 | __set_bit(OBSOLETE_ZNODE, &znode->flags); |
| 2438 | atomic_long_inc(&c->clean_zn_cnt); |
| 2439 | atomic_long_inc(&ubifs_clean_zn_cnt); |
| 2440 | } else |
| 2441 | kfree(znode); |
| 2442 | znode = zp; |
| 2443 | } while (znode->child_cnt == 1); /* while removing last child */ |
| 2444 | |
| 2445 | /* Remove from znode, entry n - 1 */ |
| 2446 | znode->child_cnt -= 1; |
| 2447 | ubifs_assert(znode->level != 0); |
| 2448 | for (i = n; i < znode->child_cnt; i++) { |
| 2449 | znode->zbranch[i] = znode->zbranch[i + 1]; |
| 2450 | if (znode->zbranch[i].znode) |
| 2451 | znode->zbranch[i].znode->iip = i; |
| 2452 | } |
| 2453 | |
| 2454 | /* |
| 2455 | * If this is the root and it has only 1 child then |
| 2456 | * collapse the tree. |
| 2457 | */ |
| 2458 | if (!znode->parent) { |
| 2459 | while (znode->child_cnt == 1 && znode->level != 0) { |
| 2460 | zp = znode; |
| 2461 | zbr = &znode->zbranch[0]; |
| 2462 | znode = get_znode(c, znode, 0); |
| 2463 | if (IS_ERR(znode)) |
| 2464 | return PTR_ERR(znode); |
| 2465 | znode = dirty_cow_znode(c, zbr); |
| 2466 | if (IS_ERR(znode)) |
| 2467 | return PTR_ERR(znode); |
| 2468 | znode->parent = NULL; |
| 2469 | znode->iip = 0; |
| 2470 | if (c->zroot.len) { |
| 2471 | err = insert_old_idx(c, c->zroot.lnum, |
| 2472 | c->zroot.offs); |
| 2473 | if (err) |
| 2474 | return err; |
| 2475 | } |
| 2476 | c->zroot.lnum = zbr->lnum; |
| 2477 | c->zroot.offs = zbr->offs; |
| 2478 | c->zroot.len = zbr->len; |
| 2479 | c->zroot.znode = znode; |
Artem Bityutskiy | f42eed7 | 2011-05-30 14:45:30 +0300 | [diff] [blame] | 2480 | ubifs_assert(!ubifs_zn_obsolete(zp)); |
| 2481 | ubifs_assert(ubifs_zn_dirty(zp)); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2482 | atomic_long_dec(&c->dirty_zn_cnt); |
| 2483 | |
| 2484 | if (zp->cnext) { |
| 2485 | __set_bit(OBSOLETE_ZNODE, &zp->flags); |
| 2486 | atomic_long_inc(&c->clean_zn_cnt); |
| 2487 | atomic_long_inc(&ubifs_clean_zn_cnt); |
| 2488 | } else |
| 2489 | kfree(zp); |
| 2490 | } |
| 2491 | } |
| 2492 | |
| 2493 | return 0; |
| 2494 | } |
| 2495 | |
| 2496 | /** |
| 2497 | * ubifs_tnc_remove - remove an index entry of a node. |
| 2498 | * @c: UBIFS file-system description object |
| 2499 | * @key: key of node |
| 2500 | * |
| 2501 | * Returns %0 on success or negative error code on failure. |
| 2502 | */ |
| 2503 | int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key) |
| 2504 | { |
| 2505 | int found, n, err = 0; |
| 2506 | struct ubifs_znode *znode; |
| 2507 | |
| 2508 | mutex_lock(&c->tnc_mutex); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2509 | dbg_tnck(key, "key "); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2510 | found = lookup_level0_dirty(c, key, &znode, &n); |
| 2511 | if (found < 0) { |
| 2512 | err = found; |
| 2513 | goto out_unlock; |
| 2514 | } |
| 2515 | if (found == 1) |
| 2516 | err = tnc_delete(c, znode, n); |
| 2517 | if (!err) |
| 2518 | err = dbg_check_tnc(c, 0); |
| 2519 | |
| 2520 | out_unlock: |
| 2521 | mutex_unlock(&c->tnc_mutex); |
| 2522 | return err; |
| 2523 | } |
| 2524 | |
| 2525 | /** |
| 2526 | * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node. |
| 2527 | * @c: UBIFS file-system description object |
| 2528 | * @key: key of node |
| 2529 | * @nm: directory entry name |
| 2530 | * |
| 2531 | * Returns %0 on success or negative error code on failure. |
| 2532 | */ |
| 2533 | int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key, |
| 2534 | const struct qstr *nm) |
| 2535 | { |
| 2536 | int n, err; |
| 2537 | struct ubifs_znode *znode; |
| 2538 | |
| 2539 | mutex_lock(&c->tnc_mutex); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2540 | dbg_tnck(key, "%.*s, key ", nm->len, nm->name); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2541 | err = lookup_level0_dirty(c, key, &znode, &n); |
| 2542 | if (err < 0) |
| 2543 | goto out_unlock; |
| 2544 | |
| 2545 | if (err) { |
| 2546 | if (c->replaying) |
| 2547 | err = fallible_resolve_collision(c, key, &znode, &n, |
| 2548 | nm, 0); |
| 2549 | else |
| 2550 | err = resolve_collision(c, key, &znode, &n, nm); |
| 2551 | dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n); |
| 2552 | if (err < 0) |
| 2553 | goto out_unlock; |
| 2554 | if (err) { |
| 2555 | /* Ensure the znode is dirtied */ |
| 2556 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
Artem Bityutskiy | c436157 | 2011-03-25 15:27:40 +0200 | [diff] [blame] | 2557 | znode = dirty_cow_bottom_up(c, znode); |
| 2558 | if (IS_ERR(znode)) { |
| 2559 | err = PTR_ERR(znode); |
| 2560 | goto out_unlock; |
| 2561 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2562 | } |
| 2563 | err = tnc_delete(c, znode, n); |
| 2564 | } |
| 2565 | } |
| 2566 | |
| 2567 | out_unlock: |
| 2568 | if (!err) |
| 2569 | err = dbg_check_tnc(c, 0); |
| 2570 | mutex_unlock(&c->tnc_mutex); |
| 2571 | return err; |
| 2572 | } |
| 2573 | |
| 2574 | /** |
| 2575 | * key_in_range - determine if a key falls within a range of keys. |
| 2576 | * @c: UBIFS file-system description object |
| 2577 | * @key: key to check |
| 2578 | * @from_key: lowest key in range |
| 2579 | * @to_key: highest key in range |
| 2580 | * |
| 2581 | * This function returns %1 if the key is in range and %0 otherwise. |
| 2582 | */ |
| 2583 | static int key_in_range(struct ubifs_info *c, union ubifs_key *key, |
| 2584 | union ubifs_key *from_key, union ubifs_key *to_key) |
| 2585 | { |
| 2586 | if (keys_cmp(c, key, from_key) < 0) |
| 2587 | return 0; |
| 2588 | if (keys_cmp(c, key, to_key) > 0) |
| 2589 | return 0; |
| 2590 | return 1; |
| 2591 | } |
| 2592 | |
| 2593 | /** |
| 2594 | * ubifs_tnc_remove_range - remove index entries in range. |
| 2595 | * @c: UBIFS file-system description object |
| 2596 | * @from_key: lowest key to remove |
| 2597 | * @to_key: highest key to remove |
| 2598 | * |
| 2599 | * This function removes index entries starting at @from_key and ending at |
| 2600 | * @to_key. This function returns zero in case of success and a negative error |
| 2601 | * code in case of failure. |
| 2602 | */ |
| 2603 | int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key, |
| 2604 | union ubifs_key *to_key) |
| 2605 | { |
| 2606 | int i, n, k, err = 0; |
| 2607 | struct ubifs_znode *znode; |
| 2608 | union ubifs_key *key; |
| 2609 | |
| 2610 | mutex_lock(&c->tnc_mutex); |
| 2611 | while (1) { |
| 2612 | /* Find first level 0 znode that contains keys to remove */ |
| 2613 | err = ubifs_lookup_level0(c, from_key, &znode, &n); |
| 2614 | if (err < 0) |
| 2615 | goto out_unlock; |
| 2616 | |
| 2617 | if (err) |
| 2618 | key = from_key; |
| 2619 | else { |
| 2620 | err = tnc_next(c, &znode, &n); |
| 2621 | if (err == -ENOENT) { |
| 2622 | err = 0; |
| 2623 | goto out_unlock; |
| 2624 | } |
| 2625 | if (err < 0) |
| 2626 | goto out_unlock; |
| 2627 | key = &znode->zbranch[n].key; |
| 2628 | if (!key_in_range(c, key, from_key, to_key)) { |
| 2629 | err = 0; |
| 2630 | goto out_unlock; |
| 2631 | } |
| 2632 | } |
| 2633 | |
| 2634 | /* Ensure the znode is dirtied */ |
| 2635 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
Artem Bityutskiy | f92b982 | 2008-12-28 11:34:26 +0200 | [diff] [blame] | 2636 | znode = dirty_cow_bottom_up(c, znode); |
| 2637 | if (IS_ERR(znode)) { |
| 2638 | err = PTR_ERR(znode); |
| 2639 | goto out_unlock; |
| 2640 | } |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2641 | } |
| 2642 | |
| 2643 | /* Remove all keys in range except the first */ |
| 2644 | for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) { |
| 2645 | key = &znode->zbranch[i].key; |
| 2646 | if (!key_in_range(c, key, from_key, to_key)) |
| 2647 | break; |
| 2648 | lnc_free(&znode->zbranch[i]); |
| 2649 | err = ubifs_add_dirt(c, znode->zbranch[i].lnum, |
| 2650 | znode->zbranch[i].len); |
| 2651 | if (err) { |
| 2652 | dbg_dump_znode(c, znode); |
| 2653 | goto out_unlock; |
| 2654 | } |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2655 | dbg_tnck(key, "removing key "); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2656 | } |
| 2657 | if (k) { |
| 2658 | for (i = n + 1 + k; i < znode->child_cnt; i++) |
| 2659 | znode->zbranch[i - k] = znode->zbranch[i]; |
| 2660 | znode->child_cnt -= k; |
| 2661 | } |
| 2662 | |
| 2663 | /* Now delete the first */ |
| 2664 | err = tnc_delete(c, znode, n); |
| 2665 | if (err) |
| 2666 | goto out_unlock; |
| 2667 | } |
| 2668 | |
| 2669 | out_unlock: |
| 2670 | if (!err) |
| 2671 | err = dbg_check_tnc(c, 0); |
| 2672 | mutex_unlock(&c->tnc_mutex); |
| 2673 | return err; |
| 2674 | } |
| 2675 | |
| 2676 | /** |
| 2677 | * ubifs_tnc_remove_ino - remove an inode from TNC. |
| 2678 | * @c: UBIFS file-system description object |
| 2679 | * @inum: inode number to remove |
| 2680 | * |
| 2681 | * This function remove inode @inum and all the extended attributes associated |
| 2682 | * with the anode from TNC and returns zero in case of success or a negative |
| 2683 | * error code in case of failure. |
| 2684 | */ |
| 2685 | int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum) |
| 2686 | { |
| 2687 | union ubifs_key key1, key2; |
| 2688 | struct ubifs_dent_node *xent, *pxent = NULL; |
| 2689 | struct qstr nm = { .name = NULL }; |
| 2690 | |
Artem Bityutskiy | e84461a | 2008-10-29 12:08:43 +0200 | [diff] [blame] | 2691 | dbg_tnc("ino %lu", (unsigned long)inum); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2692 | |
| 2693 | /* |
| 2694 | * Walk all extended attribute entries and remove them together with |
| 2695 | * corresponding extended attribute inodes. |
| 2696 | */ |
| 2697 | lowest_xent_key(c, &key1, inum); |
| 2698 | while (1) { |
| 2699 | ino_t xattr_inum; |
| 2700 | int err; |
| 2701 | |
| 2702 | xent = ubifs_tnc_next_ent(c, &key1, &nm); |
| 2703 | if (IS_ERR(xent)) { |
| 2704 | err = PTR_ERR(xent); |
| 2705 | if (err == -ENOENT) |
| 2706 | break; |
| 2707 | return err; |
| 2708 | } |
| 2709 | |
| 2710 | xattr_inum = le64_to_cpu(xent->inum); |
Artem Bityutskiy | e84461a | 2008-10-29 12:08:43 +0200 | [diff] [blame] | 2711 | dbg_tnc("xent '%s', ino %lu", xent->name, |
| 2712 | (unsigned long)xattr_inum); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2713 | |
| 2714 | nm.name = xent->name; |
| 2715 | nm.len = le16_to_cpu(xent->nlen); |
| 2716 | err = ubifs_tnc_remove_nm(c, &key1, &nm); |
| 2717 | if (err) { |
| 2718 | kfree(xent); |
| 2719 | return err; |
| 2720 | } |
| 2721 | |
| 2722 | lowest_ino_key(c, &key1, xattr_inum); |
| 2723 | highest_ino_key(c, &key2, xattr_inum); |
| 2724 | err = ubifs_tnc_remove_range(c, &key1, &key2); |
| 2725 | if (err) { |
| 2726 | kfree(xent); |
| 2727 | return err; |
| 2728 | } |
| 2729 | |
| 2730 | kfree(pxent); |
| 2731 | pxent = xent; |
| 2732 | key_read(c, &xent->key, &key1); |
| 2733 | } |
| 2734 | |
| 2735 | kfree(pxent); |
| 2736 | lowest_ino_key(c, &key1, inum); |
| 2737 | highest_ino_key(c, &key2, inum); |
| 2738 | |
| 2739 | return ubifs_tnc_remove_range(c, &key1, &key2); |
| 2740 | } |
| 2741 | |
| 2742 | /** |
| 2743 | * ubifs_tnc_next_ent - walk directory or extended attribute entries. |
| 2744 | * @c: UBIFS file-system description object |
| 2745 | * @key: key of last entry |
| 2746 | * @nm: name of last entry found or %NULL |
| 2747 | * |
| 2748 | * This function finds and reads the next directory or extended attribute entry |
| 2749 | * after the given key (@key) if there is one. @nm is used to resolve |
| 2750 | * collisions. |
| 2751 | * |
| 2752 | * If the name of the current entry is not known and only the key is known, |
| 2753 | * @nm->name has to be %NULL. In this case the semantics of this function is a |
| 2754 | * little bit different and it returns the entry corresponding to this key, not |
| 2755 | * the next one. If the key was not found, the closest "right" entry is |
| 2756 | * returned. |
| 2757 | * |
| 2758 | * If the fist entry has to be found, @key has to contain the lowest possible |
| 2759 | * key value for this inode and @name has to be %NULL. |
| 2760 | * |
| 2761 | * This function returns the found directory or extended attribute entry node |
| 2762 | * in case of success, %-ENOENT is returned if no entry was found, and a |
| 2763 | * negative error code is returned in case of failure. |
| 2764 | */ |
| 2765 | struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c, |
| 2766 | union ubifs_key *key, |
| 2767 | const struct qstr *nm) |
| 2768 | { |
| 2769 | int n, err, type = key_type(c, key); |
| 2770 | struct ubifs_znode *znode; |
| 2771 | struct ubifs_dent_node *dent; |
| 2772 | struct ubifs_zbranch *zbr; |
| 2773 | union ubifs_key *dkey; |
| 2774 | |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 2775 | dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)"); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2776 | ubifs_assert(is_hash_key(c, key)); |
| 2777 | |
| 2778 | mutex_lock(&c->tnc_mutex); |
| 2779 | err = ubifs_lookup_level0(c, key, &znode, &n); |
| 2780 | if (unlikely(err < 0)) |
| 2781 | goto out_unlock; |
| 2782 | |
| 2783 | if (nm->name) { |
| 2784 | if (err) { |
| 2785 | /* Handle collisions */ |
| 2786 | err = resolve_collision(c, key, &znode, &n, nm); |
| 2787 | dbg_tnc("rc returned %d, znode %p, n %d", |
| 2788 | err, znode, n); |
| 2789 | if (unlikely(err < 0)) |
| 2790 | goto out_unlock; |
| 2791 | } |
| 2792 | |
| 2793 | /* Now find next entry */ |
| 2794 | err = tnc_next(c, &znode, &n); |
| 2795 | if (unlikely(err)) |
| 2796 | goto out_unlock; |
| 2797 | } else { |
| 2798 | /* |
| 2799 | * The full name of the entry was not given, in which case the |
| 2800 | * behavior of this function is a little different and it |
| 2801 | * returns current entry, not the next one. |
| 2802 | */ |
| 2803 | if (!err) { |
| 2804 | /* |
| 2805 | * However, the given key does not exist in the TNC |
| 2806 | * tree and @znode/@n variables contain the closest |
| 2807 | * "preceding" element. Switch to the next one. |
| 2808 | */ |
| 2809 | err = tnc_next(c, &znode, &n); |
| 2810 | if (err) |
| 2811 | goto out_unlock; |
| 2812 | } |
| 2813 | } |
| 2814 | |
| 2815 | zbr = &znode->zbranch[n]; |
| 2816 | dent = kmalloc(zbr->len, GFP_NOFS); |
| 2817 | if (unlikely(!dent)) { |
| 2818 | err = -ENOMEM; |
| 2819 | goto out_unlock; |
| 2820 | } |
| 2821 | |
| 2822 | /* |
| 2823 | * The above 'tnc_next()' call could lead us to the next inode, check |
| 2824 | * this. |
| 2825 | */ |
| 2826 | dkey = &zbr->key; |
| 2827 | if (key_inum(c, dkey) != key_inum(c, key) || |
| 2828 | key_type(c, dkey) != type) { |
| 2829 | err = -ENOENT; |
| 2830 | goto out_free; |
| 2831 | } |
| 2832 | |
| 2833 | err = tnc_read_node_nm(c, zbr, dent); |
| 2834 | if (unlikely(err)) |
| 2835 | goto out_free; |
| 2836 | |
| 2837 | mutex_unlock(&c->tnc_mutex); |
| 2838 | return dent; |
| 2839 | |
| 2840 | out_free: |
| 2841 | kfree(dent); |
| 2842 | out_unlock: |
| 2843 | mutex_unlock(&c->tnc_mutex); |
| 2844 | return ERR_PTR(err); |
| 2845 | } |
| 2846 | |
| 2847 | /** |
| 2848 | * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit. |
| 2849 | * @c: UBIFS file-system description object |
| 2850 | * |
| 2851 | * Destroy left-over obsolete znodes from a failed commit. |
| 2852 | */ |
| 2853 | static void tnc_destroy_cnext(struct ubifs_info *c) |
| 2854 | { |
| 2855 | struct ubifs_znode *cnext; |
| 2856 | |
| 2857 | if (!c->cnext) |
| 2858 | return; |
| 2859 | ubifs_assert(c->cmt_state == COMMIT_BROKEN); |
| 2860 | cnext = c->cnext; |
| 2861 | do { |
| 2862 | struct ubifs_znode *znode = cnext; |
| 2863 | |
| 2864 | cnext = cnext->cnext; |
Artem Bityutskiy | f42eed7 | 2011-05-30 14:45:30 +0300 | [diff] [blame] | 2865 | if (ubifs_zn_obsolete(znode)) |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2866 | kfree(znode); |
| 2867 | } while (cnext && cnext != c->cnext); |
| 2868 | } |
| 2869 | |
| 2870 | /** |
| 2871 | * ubifs_tnc_close - close TNC subsystem and free all related resources. |
| 2872 | * @c: UBIFS file-system description object |
| 2873 | */ |
| 2874 | void ubifs_tnc_close(struct ubifs_info *c) |
| 2875 | { |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2876 | tnc_destroy_cnext(c); |
| 2877 | if (c->zroot.znode) { |
Artem Bityutskiy | 8370723 | 2011-05-31 14:26:07 +0300 | [diff] [blame] | 2878 | long n; |
| 2879 | |
| 2880 | ubifs_destroy_tnc_subtree(c->zroot.znode); |
| 2881 | n = atomic_long_read(&c->clean_zn_cnt); |
| 2882 | atomic_long_sub(n, &ubifs_clean_zn_cnt); |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2883 | } |
| 2884 | kfree(c->gap_lebs); |
| 2885 | kfree(c->ilebs); |
| 2886 | destroy_old_idx(c); |
| 2887 | } |
| 2888 | |
| 2889 | /** |
| 2890 | * left_znode - get the znode to the left. |
| 2891 | * @c: UBIFS file-system description object |
| 2892 | * @znode: znode |
| 2893 | * |
| 2894 | * This function returns a pointer to the znode to the left of @znode or NULL if |
| 2895 | * there is not one. A negative error code is returned on failure. |
| 2896 | */ |
| 2897 | static struct ubifs_znode *left_znode(struct ubifs_info *c, |
| 2898 | struct ubifs_znode *znode) |
| 2899 | { |
| 2900 | int level = znode->level; |
| 2901 | |
| 2902 | while (1) { |
| 2903 | int n = znode->iip - 1; |
| 2904 | |
| 2905 | /* Go up until we can go left */ |
| 2906 | znode = znode->parent; |
| 2907 | if (!znode) |
| 2908 | return NULL; |
| 2909 | if (n >= 0) { |
| 2910 | /* Now go down the rightmost branch to 'level' */ |
| 2911 | znode = get_znode(c, znode, n); |
| 2912 | if (IS_ERR(znode)) |
| 2913 | return znode; |
| 2914 | while (znode->level != level) { |
| 2915 | n = znode->child_cnt - 1; |
| 2916 | znode = get_znode(c, znode, n); |
| 2917 | if (IS_ERR(znode)) |
| 2918 | return znode; |
| 2919 | } |
| 2920 | break; |
| 2921 | } |
| 2922 | } |
| 2923 | return znode; |
| 2924 | } |
| 2925 | |
| 2926 | /** |
| 2927 | * right_znode - get the znode to the right. |
| 2928 | * @c: UBIFS file-system description object |
| 2929 | * @znode: znode |
| 2930 | * |
| 2931 | * This function returns a pointer to the znode to the right of @znode or NULL |
| 2932 | * if there is not one. A negative error code is returned on failure. |
| 2933 | */ |
| 2934 | static struct ubifs_znode *right_znode(struct ubifs_info *c, |
| 2935 | struct ubifs_znode *znode) |
| 2936 | { |
| 2937 | int level = znode->level; |
| 2938 | |
| 2939 | while (1) { |
| 2940 | int n = znode->iip + 1; |
| 2941 | |
| 2942 | /* Go up until we can go right */ |
| 2943 | znode = znode->parent; |
| 2944 | if (!znode) |
| 2945 | return NULL; |
| 2946 | if (n < znode->child_cnt) { |
| 2947 | /* Now go down the leftmost branch to 'level' */ |
| 2948 | znode = get_znode(c, znode, n); |
| 2949 | if (IS_ERR(znode)) |
| 2950 | return znode; |
| 2951 | while (znode->level != level) { |
| 2952 | znode = get_znode(c, znode, 0); |
| 2953 | if (IS_ERR(znode)) |
| 2954 | return znode; |
| 2955 | } |
| 2956 | break; |
| 2957 | } |
| 2958 | } |
| 2959 | return znode; |
| 2960 | } |
| 2961 | |
| 2962 | /** |
| 2963 | * lookup_znode - find a particular indexing node from TNC. |
| 2964 | * @c: UBIFS file-system description object |
| 2965 | * @key: index node key to lookup |
| 2966 | * @level: index node level |
| 2967 | * @lnum: index node LEB number |
| 2968 | * @offs: index node offset |
| 2969 | * |
| 2970 | * This function searches an indexing node by its first key @key and its |
| 2971 | * address @lnum:@offs. It looks up the indexing tree by pulling all indexing |
Artem Bityutskiy | ba2f48f | 2010-08-22 07:10:12 +0300 | [diff] [blame] | 2972 | * nodes it traverses to TNC. This function is called for indexing nodes which |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2973 | * were found on the media by scanning, for example when garbage-collecting or |
| 2974 | * when doing in-the-gaps commit. This means that the indexing node which is |
| 2975 | * looked for does not have to have exactly the same leftmost key @key, because |
| 2976 | * the leftmost key may have been changed, in which case TNC will contain a |
| 2977 | * dirty znode which still refers the same @lnum:@offs. This function is clever |
| 2978 | * enough to recognize such indexing nodes. |
| 2979 | * |
| 2980 | * Note, if a znode was deleted or changed too much, then this function will |
| 2981 | * not find it. For situations like this UBIFS has the old index RB-tree |
| 2982 | * (indexed by @lnum:@offs). |
| 2983 | * |
| 2984 | * This function returns a pointer to the znode found or %NULL if it is not |
| 2985 | * found. A negative error code is returned on failure. |
| 2986 | */ |
| 2987 | static struct ubifs_znode *lookup_znode(struct ubifs_info *c, |
| 2988 | union ubifs_key *key, int level, |
| 2989 | int lnum, int offs) |
| 2990 | { |
| 2991 | struct ubifs_znode *znode, *zn; |
| 2992 | int n, nn; |
| 2993 | |
Artem Bityutskiy | ba2f48f | 2010-08-22 07:10:12 +0300 | [diff] [blame] | 2994 | ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY); |
| 2995 | |
Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 2996 | /* |
| 2997 | * The arguments have probably been read off flash, so don't assume |
| 2998 | * they are valid. |
| 2999 | */ |
| 3000 | if (level < 0) |
| 3001 | return ERR_PTR(-EINVAL); |
| 3002 | |
| 3003 | /* Get the root znode */ |
| 3004 | znode = c->zroot.znode; |
| 3005 | if (!znode) { |
| 3006 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
| 3007 | if (IS_ERR(znode)) |
| 3008 | return znode; |
| 3009 | } |
| 3010 | /* Check if it is the one we are looking for */ |
| 3011 | if (c->zroot.lnum == lnum && c->zroot.offs == offs) |
| 3012 | return znode; |
| 3013 | /* Descend to the parent level i.e. (level + 1) */ |
| 3014 | if (level >= znode->level) |
| 3015 | return NULL; |
| 3016 | while (1) { |
| 3017 | ubifs_search_zbranch(c, znode, key, &n); |
| 3018 | if (n < 0) { |
| 3019 | /* |
| 3020 | * We reached a znode where the leftmost key is greater |
| 3021 | * than the key we are searching for. This is the same |
| 3022 | * situation as the one described in a huge comment at |
| 3023 | * the end of the 'ubifs_lookup_level0()' function. And |
| 3024 | * for exactly the same reasons we have to try to look |
| 3025 | * left before giving up. |
| 3026 | */ |
| 3027 | znode = left_znode(c, znode); |
| 3028 | if (!znode) |
| 3029 | return NULL; |
| 3030 | if (IS_ERR(znode)) |
| 3031 | return znode; |
| 3032 | ubifs_search_zbranch(c, znode, key, &n); |
| 3033 | ubifs_assert(n >= 0); |
| 3034 | } |
| 3035 | if (znode->level == level + 1) |
| 3036 | break; |
| 3037 | znode = get_znode(c, znode, n); |
| 3038 | if (IS_ERR(znode)) |
| 3039 | return znode; |
| 3040 | } |
| 3041 | /* Check if the child is the one we are looking for */ |
| 3042 | if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs) |
| 3043 | return get_znode(c, znode, n); |
| 3044 | /* If the key is unique, there is nowhere else to look */ |
| 3045 | if (!is_hash_key(c, key)) |
| 3046 | return NULL; |
| 3047 | /* |
| 3048 | * The key is not unique and so may be also in the znodes to either |
| 3049 | * side. |
| 3050 | */ |
| 3051 | zn = znode; |
| 3052 | nn = n; |
| 3053 | /* Look left */ |
| 3054 | while (1) { |
| 3055 | /* Move one branch to the left */ |
| 3056 | if (n) |
| 3057 | n -= 1; |
| 3058 | else { |
| 3059 | znode = left_znode(c, znode); |
| 3060 | if (!znode) |
| 3061 | break; |
| 3062 | if (IS_ERR(znode)) |
| 3063 | return znode; |
| 3064 | n = znode->child_cnt - 1; |
| 3065 | } |
| 3066 | /* Check it */ |
| 3067 | if (znode->zbranch[n].lnum == lnum && |
| 3068 | znode->zbranch[n].offs == offs) |
| 3069 | return get_znode(c, znode, n); |
| 3070 | /* Stop if the key is less than the one we are looking for */ |
| 3071 | if (keys_cmp(c, &znode->zbranch[n].key, key) < 0) |
| 3072 | break; |
| 3073 | } |
| 3074 | /* Back to the middle */ |
| 3075 | znode = zn; |
| 3076 | n = nn; |
| 3077 | /* Look right */ |
| 3078 | while (1) { |
| 3079 | /* Move one branch to the right */ |
| 3080 | if (++n >= znode->child_cnt) { |
| 3081 | znode = right_znode(c, znode); |
| 3082 | if (!znode) |
| 3083 | break; |
| 3084 | if (IS_ERR(znode)) |
| 3085 | return znode; |
| 3086 | n = 0; |
| 3087 | } |
| 3088 | /* Check it */ |
| 3089 | if (znode->zbranch[n].lnum == lnum && |
| 3090 | znode->zbranch[n].offs == offs) |
| 3091 | return get_znode(c, znode, n); |
| 3092 | /* Stop if the key is greater than the one we are looking for */ |
| 3093 | if (keys_cmp(c, &znode->zbranch[n].key, key) > 0) |
| 3094 | break; |
| 3095 | } |
| 3096 | return NULL; |
| 3097 | } |
| 3098 | |
| 3099 | /** |
| 3100 | * is_idx_node_in_tnc - determine if an index node is in the TNC. |
| 3101 | * @c: UBIFS file-system description object |
| 3102 | * @key: key of index node |
| 3103 | * @level: index node level |
| 3104 | * @lnum: LEB number of index node |
| 3105 | * @offs: offset of index node |
| 3106 | * |
| 3107 | * This function returns %0 if the index node is not referred to in the TNC, %1 |
| 3108 | * if the index node is referred to in the TNC and the corresponding znode is |
| 3109 | * dirty, %2 if an index node is referred to in the TNC and the corresponding |
| 3110 | * znode is clean, and a negative error code in case of failure. |
| 3111 | * |
| 3112 | * Note, the @key argument has to be the key of the first child. Also note, |
| 3113 | * this function relies on the fact that 0:0 is never a valid LEB number and |
| 3114 | * offset for a main-area node. |
| 3115 | */ |
| 3116 | int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level, |
| 3117 | int lnum, int offs) |
| 3118 | { |
| 3119 | struct ubifs_znode *znode; |
| 3120 | |
| 3121 | znode = lookup_znode(c, key, level, lnum, offs); |
| 3122 | if (!znode) |
| 3123 | return 0; |
| 3124 | if (IS_ERR(znode)) |
| 3125 | return PTR_ERR(znode); |
| 3126 | |
| 3127 | return ubifs_zn_dirty(znode) ? 1 : 2; |
| 3128 | } |
| 3129 | |
| 3130 | /** |
| 3131 | * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC. |
| 3132 | * @c: UBIFS file-system description object |
| 3133 | * @key: node key |
| 3134 | * @lnum: node LEB number |
| 3135 | * @offs: node offset |
| 3136 | * |
| 3137 | * This function returns %1 if the node is referred to in the TNC, %0 if it is |
| 3138 | * not, and a negative error code in case of failure. |
| 3139 | * |
| 3140 | * Note, this function relies on the fact that 0:0 is never a valid LEB number |
| 3141 | * and offset for a main-area node. |
| 3142 | */ |
| 3143 | static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, |
| 3144 | int lnum, int offs) |
| 3145 | { |
| 3146 | struct ubifs_zbranch *zbr; |
| 3147 | struct ubifs_znode *znode, *zn; |
| 3148 | int n, found, err, nn; |
| 3149 | const int unique = !is_hash_key(c, key); |
| 3150 | |
| 3151 | found = ubifs_lookup_level0(c, key, &znode, &n); |
| 3152 | if (found < 0) |
| 3153 | return found; /* Error code */ |
| 3154 | if (!found) |
| 3155 | return 0; |
| 3156 | zbr = &znode->zbranch[n]; |
| 3157 | if (lnum == zbr->lnum && offs == zbr->offs) |
| 3158 | return 1; /* Found it */ |
| 3159 | if (unique) |
| 3160 | return 0; |
| 3161 | /* |
| 3162 | * Because the key is not unique, we have to look left |
| 3163 | * and right as well |
| 3164 | */ |
| 3165 | zn = znode; |
| 3166 | nn = n; |
| 3167 | /* Look left */ |
| 3168 | while (1) { |
| 3169 | err = tnc_prev(c, &znode, &n); |
| 3170 | if (err == -ENOENT) |
| 3171 | break; |
| 3172 | if (err) |
| 3173 | return err; |
| 3174 | if (keys_cmp(c, key, &znode->zbranch[n].key)) |
| 3175 | break; |
| 3176 | zbr = &znode->zbranch[n]; |
| 3177 | if (lnum == zbr->lnum && offs == zbr->offs) |
| 3178 | return 1; /* Found it */ |
| 3179 | } |
| 3180 | /* Look right */ |
| 3181 | znode = zn; |
| 3182 | n = nn; |
| 3183 | while (1) { |
| 3184 | err = tnc_next(c, &znode, &n); |
| 3185 | if (err) { |
| 3186 | if (err == -ENOENT) |
| 3187 | return 0; |
| 3188 | return err; |
| 3189 | } |
| 3190 | if (keys_cmp(c, key, &znode->zbranch[n].key)) |
| 3191 | break; |
| 3192 | zbr = &znode->zbranch[n]; |
| 3193 | if (lnum == zbr->lnum && offs == zbr->offs) |
| 3194 | return 1; /* Found it */ |
| 3195 | } |
| 3196 | return 0; |
| 3197 | } |
| 3198 | |
| 3199 | /** |
| 3200 | * ubifs_tnc_has_node - determine whether a node is in the TNC. |
| 3201 | * @c: UBIFS file-system description object |
| 3202 | * @key: node key |
| 3203 | * @level: index node level (if it is an index node) |
| 3204 | * @lnum: node LEB number |
| 3205 | * @offs: node offset |
| 3206 | * @is_idx: non-zero if the node is an index node |
| 3207 | * |
| 3208 | * This function returns %1 if the node is in the TNC, %0 if it is not, and a |
| 3209 | * negative error code in case of failure. For index nodes, @key has to be the |
| 3210 | * key of the first child. An index node is considered to be in the TNC only if |
| 3211 | * the corresponding znode is clean or has not been loaded. |
| 3212 | */ |
| 3213 | int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level, |
| 3214 | int lnum, int offs, int is_idx) |
| 3215 | { |
| 3216 | int err; |
| 3217 | |
| 3218 | mutex_lock(&c->tnc_mutex); |
| 3219 | if (is_idx) { |
| 3220 | err = is_idx_node_in_tnc(c, key, level, lnum, offs); |
| 3221 | if (err < 0) |
| 3222 | goto out_unlock; |
| 3223 | if (err == 1) |
| 3224 | /* The index node was found but it was dirty */ |
| 3225 | err = 0; |
| 3226 | else if (err == 2) |
| 3227 | /* The index node was found and it was clean */ |
| 3228 | err = 1; |
| 3229 | else |
| 3230 | BUG_ON(err != 0); |
| 3231 | } else |
| 3232 | err = is_leaf_node_in_tnc(c, key, lnum, offs); |
| 3233 | |
| 3234 | out_unlock: |
| 3235 | mutex_unlock(&c->tnc_mutex); |
| 3236 | return err; |
| 3237 | } |
| 3238 | |
| 3239 | /** |
| 3240 | * ubifs_dirty_idx_node - dirty an index node. |
| 3241 | * @c: UBIFS file-system description object |
| 3242 | * @key: index node key |
| 3243 | * @level: index node level |
| 3244 | * @lnum: index node LEB number |
| 3245 | * @offs: index node offset |
| 3246 | * |
| 3247 | * This function loads and dirties an index node so that it can be garbage |
| 3248 | * collected. The @key argument has to be the key of the first child. This |
| 3249 | * function relies on the fact that 0:0 is never a valid LEB number and offset |
| 3250 | * for a main-area node. Returns %0 on success and a negative error code on |
| 3251 | * failure. |
| 3252 | */ |
| 3253 | int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level, |
| 3254 | int lnum, int offs) |
| 3255 | { |
| 3256 | struct ubifs_znode *znode; |
| 3257 | int err = 0; |
| 3258 | |
| 3259 | mutex_lock(&c->tnc_mutex); |
| 3260 | znode = lookup_znode(c, key, level, lnum, offs); |
| 3261 | if (!znode) |
| 3262 | goto out_unlock; |
| 3263 | if (IS_ERR(znode)) { |
| 3264 | err = PTR_ERR(znode); |
| 3265 | goto out_unlock; |
| 3266 | } |
| 3267 | znode = dirty_cow_bottom_up(c, znode); |
| 3268 | if (IS_ERR(znode)) { |
| 3269 | err = PTR_ERR(znode); |
| 3270 | goto out_unlock; |
| 3271 | } |
| 3272 | |
| 3273 | out_unlock: |
| 3274 | mutex_unlock(&c->tnc_mutex); |
| 3275 | return err; |
| 3276 | } |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 3277 | |
| 3278 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 3279 | |
| 3280 | /** |
| 3281 | * dbg_check_inode_size - check if inode size is correct. |
| 3282 | * @c: UBIFS file-system description object |
| 3283 | * @inum: inode number |
| 3284 | * @size: inode size |
| 3285 | * |
| 3286 | * This function makes sure that the inode size (@size) is correct and it does |
| 3287 | * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL |
| 3288 | * if it has a data page beyond @size, and other negative error code in case of |
| 3289 | * other errors. |
| 3290 | */ |
| 3291 | int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode, |
| 3292 | loff_t size) |
| 3293 | { |
| 3294 | int err, n; |
| 3295 | union ubifs_key from_key, to_key, *key; |
| 3296 | struct ubifs_znode *znode; |
| 3297 | unsigned int block; |
| 3298 | |
| 3299 | if (!S_ISREG(inode->i_mode)) |
| 3300 | return 0; |
Artem Bityutskiy | 2b1844a | 2011-06-03 08:31:29 +0300 | [diff] [blame] | 3301 | if (!dbg_is_chk_gen(c)) |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 3302 | return 0; |
| 3303 | |
| 3304 | block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT; |
| 3305 | data_key_init(c, &from_key, inode->i_ino, block); |
| 3306 | highest_data_key(c, &to_key, inode->i_ino); |
| 3307 | |
| 3308 | mutex_lock(&c->tnc_mutex); |
| 3309 | err = ubifs_lookup_level0(c, &from_key, &znode, &n); |
| 3310 | if (err < 0) |
| 3311 | goto out_unlock; |
| 3312 | |
| 3313 | if (err) { |
| 3314 | err = -EINVAL; |
| 3315 | key = &from_key; |
| 3316 | goto out_dump; |
| 3317 | } |
| 3318 | |
| 3319 | err = tnc_next(c, &znode, &n); |
| 3320 | if (err == -ENOENT) { |
| 3321 | err = 0; |
| 3322 | goto out_unlock; |
| 3323 | } |
| 3324 | if (err < 0) |
| 3325 | goto out_unlock; |
| 3326 | |
| 3327 | ubifs_assert(err == 0); |
| 3328 | key = &znode->zbranch[n].key; |
| 3329 | if (!key_in_range(c, key, &from_key, &to_key)) |
| 3330 | goto out_unlock; |
| 3331 | |
| 3332 | out_dump: |
| 3333 | block = key_block(c, key); |
Artem Bityutskiy | 515315a | 2012-01-13 12:33:53 +0200 | [diff] [blame] | 3334 | ubifs_err("inode %lu has size %lld, but there are data at offset %lld", |
| 3335 | (unsigned long)inode->i_ino, size, |
| 3336 | ((loff_t)block) << UBIFS_BLOCK_SHIFT); |
Artem Bityutskiy | 4315fb4 | 2011-05-25 17:32:42 +0300 | [diff] [blame] | 3337 | mutex_unlock(&c->tnc_mutex); |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 3338 | dbg_dump_inode(c, inode); |
| 3339 | dbg_dump_stack(); |
Artem Bityutskiy | 4315fb4 | 2011-05-25 17:32:42 +0300 | [diff] [blame] | 3340 | return -EINVAL; |
Artem Bityutskiy | e3c3efc | 2009-08-27 16:34:19 +0300 | [diff] [blame] | 3341 | |
| 3342 | out_unlock: |
| 3343 | mutex_unlock(&c->tnc_mutex); |
| 3344 | return err; |
| 3345 | } |
| 3346 | |
| 3347 | #endif /* CONFIG_UBIFS_FS_DEBUG */ |