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 | /* This file implements TNC functions for committing */ |
| 24 | |
| 25 | #include "ubifs.h" |
| 26 | |
| 27 | /** |
| 28 | * make_idx_node - make an index node for fill-the-gaps method of TNC commit. |
| 29 | * @c: UBIFS file-system description object |
| 30 | * @idx: buffer in which to place new index node |
| 31 | * @znode: znode from which to make new index node |
| 32 | * @lnum: LEB number where new index node will be written |
| 33 | * @offs: offset where new index node will be written |
| 34 | * @len: length of new index node |
| 35 | */ |
| 36 | static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx, |
| 37 | struct ubifs_znode *znode, int lnum, int offs, int len) |
| 38 | { |
| 39 | struct ubifs_znode *zp; |
| 40 | int i, err; |
| 41 | |
| 42 | /* Make index node */ |
| 43 | idx->ch.node_type = UBIFS_IDX_NODE; |
| 44 | idx->child_cnt = cpu_to_le16(znode->child_cnt); |
| 45 | idx->level = cpu_to_le16(znode->level); |
| 46 | for (i = 0; i < znode->child_cnt; i++) { |
| 47 | struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); |
| 48 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; |
| 49 | |
| 50 | key_write_idx(c, &zbr->key, &br->key); |
| 51 | br->lnum = cpu_to_le32(zbr->lnum); |
| 52 | br->offs = cpu_to_le32(zbr->offs); |
| 53 | br->len = cpu_to_le32(zbr->len); |
| 54 | if (!zbr->lnum || !zbr->len) { |
| 55 | ubifs_err("bad ref in znode"); |
| 56 | dbg_dump_znode(c, znode); |
| 57 | if (zbr->znode) |
| 58 | dbg_dump_znode(c, zbr->znode); |
| 59 | } |
| 60 | } |
| 61 | ubifs_prepare_node(c, idx, len, 0); |
| 62 | |
| 63 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 64 | znode->lnum = lnum; |
| 65 | znode->offs = offs; |
| 66 | znode->len = len; |
| 67 | #endif |
| 68 | |
| 69 | err = insert_old_idx_znode(c, znode); |
| 70 | |
| 71 | /* Update the parent */ |
| 72 | zp = znode->parent; |
| 73 | if (zp) { |
| 74 | struct ubifs_zbranch *zbr; |
| 75 | |
| 76 | zbr = &zp->zbranch[znode->iip]; |
| 77 | zbr->lnum = lnum; |
| 78 | zbr->offs = offs; |
| 79 | zbr->len = len; |
| 80 | } else { |
| 81 | c->zroot.lnum = lnum; |
| 82 | c->zroot.offs = offs; |
| 83 | c->zroot.len = len; |
| 84 | } |
| 85 | c->calc_idx_sz += ALIGN(len, 8); |
| 86 | |
| 87 | atomic_long_dec(&c->dirty_zn_cnt); |
| 88 | |
| 89 | ubifs_assert(ubifs_zn_dirty(znode)); |
| 90 | ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); |
| 91 | |
| 92 | __clear_bit(DIRTY_ZNODE, &znode->flags); |
| 93 | __clear_bit(COW_ZNODE, &znode->flags); |
| 94 | |
| 95 | return err; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * fill_gap - make index nodes in gaps in dirty index LEBs. |
| 100 | * @c: UBIFS file-system description object |
| 101 | * @lnum: LEB number that gap appears in |
| 102 | * @gap_start: offset of start of gap |
| 103 | * @gap_end: offset of end of gap |
| 104 | * @dirt: adds dirty space to this |
| 105 | * |
| 106 | * This function returns the number of index nodes written into the gap. |
| 107 | */ |
| 108 | static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end, |
| 109 | int *dirt) |
| 110 | { |
| 111 | int len, gap_remains, gap_pos, written, pad_len; |
| 112 | |
| 113 | ubifs_assert((gap_start & 7) == 0); |
| 114 | ubifs_assert((gap_end & 7) == 0); |
| 115 | ubifs_assert(gap_end >= gap_start); |
| 116 | |
| 117 | gap_remains = gap_end - gap_start; |
| 118 | if (!gap_remains) |
| 119 | return 0; |
| 120 | gap_pos = gap_start; |
| 121 | written = 0; |
| 122 | while (c->enext) { |
| 123 | len = ubifs_idx_node_sz(c, c->enext->child_cnt); |
| 124 | if (len < gap_remains) { |
| 125 | struct ubifs_znode *znode = c->enext; |
| 126 | const int alen = ALIGN(len, 8); |
| 127 | int err; |
| 128 | |
| 129 | ubifs_assert(alen <= gap_remains); |
| 130 | err = make_idx_node(c, c->ileb_buf + gap_pos, znode, |
| 131 | lnum, gap_pos, len); |
| 132 | if (err) |
| 133 | return err; |
| 134 | gap_remains -= alen; |
| 135 | gap_pos += alen; |
| 136 | c->enext = znode->cnext; |
| 137 | if (c->enext == c->cnext) |
| 138 | c->enext = NULL; |
| 139 | written += 1; |
| 140 | } else |
| 141 | break; |
| 142 | } |
| 143 | if (gap_end == c->leb_size) { |
| 144 | c->ileb_len = ALIGN(gap_pos, c->min_io_size); |
| 145 | /* Pad to end of min_io_size */ |
| 146 | pad_len = c->ileb_len - gap_pos; |
| 147 | } else |
| 148 | /* Pad to end of gap */ |
| 149 | pad_len = gap_remains; |
| 150 | dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d", |
| 151 | lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len); |
| 152 | ubifs_pad(c, c->ileb_buf + gap_pos, pad_len); |
| 153 | *dirt += pad_len; |
| 154 | return written; |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * find_old_idx - find an index node obsoleted since the last commit start. |
| 159 | * @c: UBIFS file-system description object |
| 160 | * @lnum: LEB number of obsoleted index node |
| 161 | * @offs: offset of obsoleted index node |
| 162 | * |
| 163 | * Returns %1 if found and %0 otherwise. |
| 164 | */ |
| 165 | static int find_old_idx(struct ubifs_info *c, int lnum, int offs) |
| 166 | { |
| 167 | struct ubifs_old_idx *o; |
| 168 | struct rb_node *p; |
| 169 | |
| 170 | p = c->old_idx.rb_node; |
| 171 | while (p) { |
| 172 | o = rb_entry(p, struct ubifs_old_idx, rb); |
| 173 | if (lnum < o->lnum) |
| 174 | p = p->rb_left; |
| 175 | else if (lnum > o->lnum) |
| 176 | p = p->rb_right; |
| 177 | else if (offs < o->offs) |
| 178 | p = p->rb_left; |
| 179 | else if (offs > o->offs) |
| 180 | p = p->rb_right; |
| 181 | else |
| 182 | return 1; |
| 183 | } |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | /** |
| 188 | * is_idx_node_in_use - determine if an index node can be overwritten. |
| 189 | * @c: UBIFS file-system description object |
| 190 | * @key: key of index node |
| 191 | * @level: index node level |
| 192 | * @lnum: LEB number of index node |
| 193 | * @offs: offset of index node |
| 194 | * |
| 195 | * If @key / @lnum / @offs identify an index node that was not part of the old |
| 196 | * index, then this function returns %0 (obsolete). Else if the index node was |
| 197 | * part of the old index but is now dirty %1 is returned, else if it is clean %2 |
| 198 | * is returned. A negative error code is returned on failure. |
| 199 | */ |
| 200 | static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key, |
| 201 | int level, int lnum, int offs) |
| 202 | { |
| 203 | int ret; |
| 204 | |
| 205 | ret = is_idx_node_in_tnc(c, key, level, lnum, offs); |
| 206 | if (ret < 0) |
| 207 | return ret; /* Error code */ |
| 208 | if (ret == 0) |
| 209 | if (find_old_idx(c, lnum, offs)) |
| 210 | return 1; |
| 211 | return ret; |
| 212 | } |
| 213 | |
| 214 | /** |
| 215 | * layout_leb_in_gaps - layout index nodes using in-the-gaps method. |
| 216 | * @c: UBIFS file-system description object |
| 217 | * @p: return LEB number here |
| 218 | * |
| 219 | * This function lays out new index nodes for dirty znodes using in-the-gaps |
| 220 | * method of TNC commit. |
| 221 | * This function merely puts the next znode into the next gap, making no attempt |
| 222 | * to try to maximise the number of znodes that fit. |
| 223 | * This function returns the number of index nodes written into the gaps, or a |
| 224 | * negative error code on failure. |
| 225 | */ |
| 226 | static int layout_leb_in_gaps(struct ubifs_info *c, int *p) |
| 227 | { |
| 228 | struct ubifs_scan_leb *sleb; |
| 229 | struct ubifs_scan_node *snod; |
| 230 | int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written; |
| 231 | |
| 232 | tot_written = 0; |
| 233 | /* Get an index LEB with lots of obsolete index nodes */ |
| 234 | lnum = ubifs_find_dirty_idx_leb(c); |
| 235 | if (lnum < 0) |
| 236 | /* |
| 237 | * There also may be dirt in the index head that could be |
| 238 | * filled, however we do not check there at present. |
| 239 | */ |
| 240 | return lnum; /* Error code */ |
| 241 | *p = lnum; |
| 242 | dbg_gc("LEB %d", lnum); |
| 243 | /* |
| 244 | * Scan the index LEB. We use the generic scan for this even though |
| 245 | * it is more comprehensive and less efficient than is needed for this |
| 246 | * purpose. |
| 247 | */ |
| 248 | sleb = ubifs_scan(c, lnum, 0, c->ileb_buf); |
| 249 | c->ileb_len = 0; |
| 250 | if (IS_ERR(sleb)) |
| 251 | return PTR_ERR(sleb); |
| 252 | gap_start = 0; |
| 253 | list_for_each_entry(snod, &sleb->nodes, list) { |
| 254 | struct ubifs_idx_node *idx; |
| 255 | int in_use, level; |
| 256 | |
| 257 | ubifs_assert(snod->type == UBIFS_IDX_NODE); |
| 258 | idx = snod->node; |
| 259 | key_read(c, ubifs_idx_key(c, idx), &snod->key); |
| 260 | level = le16_to_cpu(idx->level); |
| 261 | /* Determine if the index node is in use (not obsolete) */ |
| 262 | in_use = is_idx_node_in_use(c, &snod->key, level, lnum, |
| 263 | snod->offs); |
| 264 | if (in_use < 0) { |
| 265 | ubifs_scan_destroy(sleb); |
| 266 | return in_use; /* Error code */ |
| 267 | } |
| 268 | if (in_use) { |
| 269 | if (in_use == 1) |
| 270 | dirt += ALIGN(snod->len, 8); |
| 271 | /* |
| 272 | * The obsolete index nodes form gaps that can be |
| 273 | * overwritten. This gap has ended because we have |
| 274 | * found an index node that is still in use |
| 275 | * i.e. not obsolete |
| 276 | */ |
| 277 | gap_end = snod->offs; |
| 278 | /* Try to fill gap */ |
| 279 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); |
| 280 | if (written < 0) { |
| 281 | ubifs_scan_destroy(sleb); |
| 282 | return written; /* Error code */ |
| 283 | } |
| 284 | tot_written += written; |
| 285 | gap_start = ALIGN(snod->offs + snod->len, 8); |
| 286 | } |
| 287 | } |
| 288 | ubifs_scan_destroy(sleb); |
| 289 | c->ileb_len = c->leb_size; |
| 290 | gap_end = c->leb_size; |
| 291 | /* Try to fill gap */ |
| 292 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); |
| 293 | if (written < 0) |
| 294 | return written; /* Error code */ |
| 295 | tot_written += written; |
| 296 | if (tot_written == 0) { |
| 297 | struct ubifs_lprops lp; |
| 298 | |
| 299 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); |
| 300 | err = ubifs_read_one_lp(c, lnum, &lp); |
| 301 | if (err) |
| 302 | return err; |
| 303 | if (lp.free == c->leb_size) { |
| 304 | /* |
| 305 | * We must have snatched this LEB from the idx_gc list |
| 306 | * so we need to correct the free and dirty space. |
| 307 | */ |
| 308 | err = ubifs_change_one_lp(c, lnum, |
| 309 | c->leb_size - c->ileb_len, |
| 310 | dirt, 0, 0, 0); |
| 311 | if (err) |
| 312 | return err; |
| 313 | } |
| 314 | return 0; |
| 315 | } |
| 316 | err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt, |
| 317 | 0, 0, 0); |
| 318 | if (err) |
| 319 | return err; |
| 320 | err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len, |
| 321 | UBI_SHORTTERM); |
| 322 | if (err) |
| 323 | return err; |
| 324 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); |
| 325 | return tot_written; |
| 326 | } |
| 327 | |
| 328 | /** |
| 329 | * get_leb_cnt - calculate the number of empty LEBs needed to commit. |
| 330 | * @c: UBIFS file-system description object |
| 331 | * @cnt: number of znodes to commit |
| 332 | * |
| 333 | * This function returns the number of empty LEBs needed to commit @cnt znodes |
| 334 | * to the current index head. The number is not exact and may be more than |
| 335 | * needed. |
| 336 | */ |
| 337 | static int get_leb_cnt(struct ubifs_info *c, int cnt) |
| 338 | { |
| 339 | int d; |
| 340 | |
| 341 | /* Assume maximum index node size (i.e. overestimate space needed) */ |
| 342 | cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz; |
| 343 | if (cnt < 0) |
| 344 | cnt = 0; |
| 345 | d = c->leb_size / c->max_idx_node_sz; |
| 346 | return DIV_ROUND_UP(cnt, d); |
| 347 | } |
| 348 | |
| 349 | /** |
| 350 | * layout_in_gaps - in-the-gaps method of committing TNC. |
| 351 | * @c: UBIFS file-system description object |
| 352 | * @cnt: number of dirty znodes to commit. |
| 353 | * |
| 354 | * This function lays out new index nodes for dirty znodes using in-the-gaps |
| 355 | * method of TNC commit. |
| 356 | * |
| 357 | * This function returns %0 on success and a negative error code on failure. |
| 358 | */ |
| 359 | static int layout_in_gaps(struct ubifs_info *c, int cnt) |
| 360 | { |
| 361 | int err, leb_needed_cnt, written, *p; |
| 362 | |
| 363 | dbg_gc("%d znodes to write", cnt); |
| 364 | |
| 365 | c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS); |
| 366 | if (!c->gap_lebs) |
| 367 | return -ENOMEM; |
| 368 | |
| 369 | p = c->gap_lebs; |
| 370 | do { |
| 371 | ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs); |
| 372 | written = layout_leb_in_gaps(c, p); |
| 373 | if (written < 0) { |
| 374 | err = written; |
| 375 | if (err == -ENOSPC) { |
| 376 | if (!dbg_force_in_the_gaps_enabled) { |
| 377 | /* |
| 378 | * Do not print scary warnings if the |
| 379 | * debugging option which forces |
| 380 | * in-the-gaps is enabled. |
| 381 | */ |
| 382 | ubifs_err("out of space"); |
| 383 | spin_lock(&c->space_lock); |
| 384 | dbg_dump_budg(c); |
| 385 | spin_unlock(&c->space_lock); |
| 386 | dbg_dump_lprops(c); |
| 387 | } |
| 388 | /* Try to commit anyway */ |
| 389 | err = 0; |
| 390 | break; |
| 391 | } |
| 392 | kfree(c->gap_lebs); |
| 393 | c->gap_lebs = NULL; |
| 394 | return err; |
| 395 | } |
| 396 | p++; |
| 397 | cnt -= written; |
| 398 | leb_needed_cnt = get_leb_cnt(c, cnt); |
| 399 | dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt, |
| 400 | leb_needed_cnt, c->ileb_cnt); |
| 401 | } while (leb_needed_cnt > c->ileb_cnt); |
| 402 | |
| 403 | *p = -1; |
| 404 | return 0; |
| 405 | } |
| 406 | |
| 407 | /** |
| 408 | * layout_in_empty_space - layout index nodes in empty space. |
| 409 | * @c: UBIFS file-system description object |
| 410 | * |
| 411 | * This function lays out new index nodes for dirty znodes using empty LEBs. |
| 412 | * |
| 413 | * This function returns %0 on success and a negative error code on failure. |
| 414 | */ |
| 415 | static int layout_in_empty_space(struct ubifs_info *c) |
| 416 | { |
| 417 | struct ubifs_znode *znode, *cnext, *zp; |
| 418 | int lnum, offs, len, next_len, buf_len, buf_offs, used, avail; |
| 419 | int wlen, blen, err; |
| 420 | |
| 421 | cnext = c->enext; |
| 422 | if (!cnext) |
| 423 | return 0; |
| 424 | |
| 425 | lnum = c->ihead_lnum; |
| 426 | buf_offs = c->ihead_offs; |
| 427 | |
| 428 | buf_len = ubifs_idx_node_sz(c, c->fanout); |
| 429 | buf_len = ALIGN(buf_len, c->min_io_size); |
| 430 | used = 0; |
| 431 | avail = buf_len; |
| 432 | |
| 433 | /* Ensure there is enough room for first write */ |
| 434 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
| 435 | if (buf_offs + next_len > c->leb_size) |
| 436 | lnum = -1; |
| 437 | |
| 438 | while (1) { |
| 439 | znode = cnext; |
| 440 | |
| 441 | len = ubifs_idx_node_sz(c, znode->child_cnt); |
| 442 | |
| 443 | /* Determine the index node position */ |
| 444 | if (lnum == -1) { |
| 445 | if (c->ileb_nxt >= c->ileb_cnt) { |
| 446 | ubifs_err("out of space"); |
| 447 | return -ENOSPC; |
| 448 | } |
| 449 | lnum = c->ilebs[c->ileb_nxt++]; |
| 450 | buf_offs = 0; |
| 451 | used = 0; |
| 452 | avail = buf_len; |
| 453 | } |
| 454 | |
| 455 | offs = buf_offs + used; |
| 456 | |
| 457 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 458 | znode->lnum = lnum; |
| 459 | znode->offs = offs; |
| 460 | znode->len = len; |
| 461 | #endif |
| 462 | |
| 463 | /* Update the parent */ |
| 464 | zp = znode->parent; |
| 465 | if (zp) { |
| 466 | struct ubifs_zbranch *zbr; |
| 467 | int i; |
| 468 | |
| 469 | i = znode->iip; |
| 470 | zbr = &zp->zbranch[i]; |
| 471 | zbr->lnum = lnum; |
| 472 | zbr->offs = offs; |
| 473 | zbr->len = len; |
| 474 | } else { |
| 475 | c->zroot.lnum = lnum; |
| 476 | c->zroot.offs = offs; |
| 477 | c->zroot.len = len; |
| 478 | } |
| 479 | c->calc_idx_sz += ALIGN(len, 8); |
| 480 | |
| 481 | /* |
| 482 | * Once lprops is updated, we can decrease the dirty znode count |
| 483 | * but it is easier to just do it here. |
| 484 | */ |
| 485 | atomic_long_dec(&c->dirty_zn_cnt); |
| 486 | |
| 487 | /* |
| 488 | * Calculate the next index node length to see if there is |
| 489 | * enough room for it |
| 490 | */ |
| 491 | cnext = znode->cnext; |
| 492 | if (cnext == c->cnext) |
| 493 | next_len = 0; |
| 494 | else |
| 495 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
| 496 | |
| 497 | if (c->min_io_size == 1) { |
| 498 | buf_offs += ALIGN(len, 8); |
| 499 | if (next_len) { |
| 500 | if (buf_offs + next_len <= c->leb_size) |
| 501 | continue; |
| 502 | err = ubifs_update_one_lp(c, lnum, 0, |
| 503 | c->leb_size - buf_offs, 0, 0); |
| 504 | if (err) |
| 505 | return err; |
| 506 | lnum = -1; |
| 507 | continue; |
| 508 | } |
| 509 | err = ubifs_update_one_lp(c, lnum, |
| 510 | c->leb_size - buf_offs, 0, 0, 0); |
| 511 | if (err) |
| 512 | return err; |
| 513 | break; |
| 514 | } |
| 515 | |
| 516 | /* Update buffer positions */ |
| 517 | wlen = used + len; |
| 518 | used += ALIGN(len, 8); |
| 519 | avail -= ALIGN(len, 8); |
| 520 | |
| 521 | if (next_len != 0 && |
| 522 | buf_offs + used + next_len <= c->leb_size && |
| 523 | avail > 0) |
| 524 | continue; |
| 525 | |
| 526 | if (avail <= 0 && next_len && |
| 527 | buf_offs + used + next_len <= c->leb_size) |
| 528 | blen = buf_len; |
| 529 | else |
| 530 | blen = ALIGN(wlen, c->min_io_size); |
| 531 | |
| 532 | /* The buffer is full or there are no more znodes to do */ |
| 533 | buf_offs += blen; |
| 534 | if (next_len) { |
| 535 | if (buf_offs + next_len > c->leb_size) { |
| 536 | err = ubifs_update_one_lp(c, lnum, |
| 537 | c->leb_size - buf_offs, blen - used, |
| 538 | 0, 0); |
| 539 | if (err) |
| 540 | return err; |
| 541 | lnum = -1; |
| 542 | } |
| 543 | used -= blen; |
| 544 | if (used < 0) |
| 545 | used = 0; |
| 546 | avail = buf_len - used; |
| 547 | continue; |
| 548 | } |
| 549 | err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs, |
| 550 | blen - used, 0, 0); |
| 551 | if (err) |
| 552 | return err; |
| 553 | break; |
| 554 | } |
| 555 | |
| 556 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 557 | c->new_ihead_lnum = lnum; |
| 558 | c->new_ihead_offs = buf_offs; |
| 559 | #endif |
| 560 | |
| 561 | return 0; |
| 562 | } |
| 563 | |
| 564 | /** |
| 565 | * layout_commit - determine positions of index nodes to commit. |
| 566 | * @c: UBIFS file-system description object |
| 567 | * @no_space: indicates that insufficient empty LEBs were allocated |
| 568 | * @cnt: number of znodes to commit |
| 569 | * |
| 570 | * Calculate and update the positions of index nodes to commit. If there were |
| 571 | * an insufficient number of empty LEBs allocated, then index nodes are placed |
| 572 | * into the gaps created by obsolete index nodes in non-empty index LEBs. For |
| 573 | * this purpose, an obsolete index node is one that was not in the index as at |
| 574 | * the end of the last commit. To write "in-the-gaps" requires that those index |
| 575 | * LEBs are updated atomically in-place. |
| 576 | */ |
| 577 | static int layout_commit(struct ubifs_info *c, int no_space, int cnt) |
| 578 | { |
| 579 | int err; |
| 580 | |
| 581 | if (no_space) { |
| 582 | err = layout_in_gaps(c, cnt); |
| 583 | if (err) |
| 584 | return err; |
| 585 | } |
| 586 | err = layout_in_empty_space(c); |
| 587 | return err; |
| 588 | } |
| 589 | |
| 590 | /** |
| 591 | * find_first_dirty - find first dirty znode. |
| 592 | * @znode: znode to begin searching from |
| 593 | */ |
| 594 | static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode) |
| 595 | { |
| 596 | int i, cont; |
| 597 | |
| 598 | if (!znode) |
| 599 | return NULL; |
| 600 | |
| 601 | while (1) { |
| 602 | if (znode->level == 0) { |
| 603 | if (ubifs_zn_dirty(znode)) |
| 604 | return znode; |
| 605 | return NULL; |
| 606 | } |
| 607 | cont = 0; |
| 608 | for (i = 0; i < znode->child_cnt; i++) { |
| 609 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; |
| 610 | |
| 611 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) { |
| 612 | znode = zbr->znode; |
| 613 | cont = 1; |
| 614 | break; |
| 615 | } |
| 616 | } |
| 617 | if (!cont) { |
| 618 | if (ubifs_zn_dirty(znode)) |
| 619 | return znode; |
| 620 | return NULL; |
| 621 | } |
| 622 | } |
| 623 | } |
| 624 | |
| 625 | /** |
| 626 | * find_next_dirty - find next dirty znode. |
| 627 | * @znode: znode to begin searching from |
| 628 | */ |
| 629 | static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode) |
| 630 | { |
| 631 | int n = znode->iip + 1; |
| 632 | |
| 633 | znode = znode->parent; |
| 634 | if (!znode) |
| 635 | return NULL; |
| 636 | for (; n < znode->child_cnt; n++) { |
| 637 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
| 638 | |
| 639 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) |
| 640 | return find_first_dirty(zbr->znode); |
| 641 | } |
| 642 | return znode; |
| 643 | } |
| 644 | |
| 645 | /** |
| 646 | * get_znodes_to_commit - create list of dirty znodes to commit. |
| 647 | * @c: UBIFS file-system description object |
| 648 | * |
| 649 | * This function returns the number of znodes to commit. |
| 650 | */ |
| 651 | static int get_znodes_to_commit(struct ubifs_info *c) |
| 652 | { |
| 653 | struct ubifs_znode *znode, *cnext; |
| 654 | int cnt = 0; |
| 655 | |
| 656 | c->cnext = find_first_dirty(c->zroot.znode); |
| 657 | znode = c->enext = c->cnext; |
| 658 | if (!znode) { |
| 659 | dbg_cmt("no znodes to commit"); |
| 660 | return 0; |
| 661 | } |
| 662 | cnt += 1; |
| 663 | while (1) { |
| 664 | ubifs_assert(!test_bit(COW_ZNODE, &znode->flags)); |
| 665 | __set_bit(COW_ZNODE, &znode->flags); |
| 666 | znode->alt = 0; |
| 667 | cnext = find_next_dirty(znode); |
| 668 | if (!cnext) { |
| 669 | znode->cnext = c->cnext; |
| 670 | break; |
| 671 | } |
| 672 | znode->cnext = cnext; |
| 673 | znode = cnext; |
| 674 | cnt += 1; |
| 675 | } |
| 676 | dbg_cmt("committing %d znodes", cnt); |
| 677 | ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt)); |
| 678 | return cnt; |
| 679 | } |
| 680 | |
| 681 | /** |
| 682 | * alloc_idx_lebs - allocate empty LEBs to be used to commit. |
| 683 | * @c: UBIFS file-system description object |
| 684 | * @cnt: number of znodes to commit |
| 685 | * |
| 686 | * This function returns %-ENOSPC if it cannot allocate a sufficient number of |
| 687 | * empty LEBs. %0 is returned on success, otherwise a negative error code |
| 688 | * is returned. |
| 689 | */ |
| 690 | static int alloc_idx_lebs(struct ubifs_info *c, int cnt) |
| 691 | { |
| 692 | int i, leb_cnt, lnum; |
| 693 | |
| 694 | c->ileb_cnt = 0; |
| 695 | c->ileb_nxt = 0; |
| 696 | leb_cnt = get_leb_cnt(c, cnt); |
| 697 | dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt); |
| 698 | if (!leb_cnt) |
| 699 | return 0; |
| 700 | c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS); |
| 701 | if (!c->ilebs) |
| 702 | return -ENOMEM; |
| 703 | for (i = 0; i < leb_cnt; i++) { |
| 704 | lnum = ubifs_find_free_leb_for_idx(c); |
| 705 | if (lnum < 0) |
| 706 | return lnum; |
| 707 | c->ilebs[c->ileb_cnt++] = lnum; |
| 708 | dbg_cmt("LEB %d", lnum); |
| 709 | } |
| 710 | if (dbg_force_in_the_gaps()) |
| 711 | return -ENOSPC; |
| 712 | return 0; |
| 713 | } |
| 714 | |
| 715 | /** |
| 716 | * free_unused_idx_lebs - free unused LEBs that were allocated for the commit. |
| 717 | * @c: UBIFS file-system description object |
| 718 | * |
| 719 | * It is possible that we allocate more empty LEBs for the commit than we need. |
| 720 | * This functions frees the surplus. |
| 721 | * |
| 722 | * This function returns %0 on success and a negative error code on failure. |
| 723 | */ |
| 724 | static int free_unused_idx_lebs(struct ubifs_info *c) |
| 725 | { |
| 726 | int i, err = 0, lnum, er; |
| 727 | |
| 728 | for (i = c->ileb_nxt; i < c->ileb_cnt; i++) { |
| 729 | lnum = c->ilebs[i]; |
| 730 | dbg_cmt("LEB %d", lnum); |
| 731 | er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, |
| 732 | LPROPS_INDEX | LPROPS_TAKEN, 0); |
| 733 | if (!err) |
| 734 | err = er; |
| 735 | } |
| 736 | return err; |
| 737 | } |
| 738 | |
| 739 | /** |
| 740 | * free_idx_lebs - free unused LEBs after commit end. |
| 741 | * @c: UBIFS file-system description object |
| 742 | * |
| 743 | * This function returns %0 on success and a negative error code on failure. |
| 744 | */ |
| 745 | static int free_idx_lebs(struct ubifs_info *c) |
| 746 | { |
| 747 | int err; |
| 748 | |
| 749 | err = free_unused_idx_lebs(c); |
| 750 | kfree(c->ilebs); |
| 751 | c->ilebs = NULL; |
| 752 | return err; |
| 753 | } |
| 754 | |
| 755 | /** |
| 756 | * ubifs_tnc_start_commit - start TNC commit. |
| 757 | * @c: UBIFS file-system description object |
| 758 | * @zroot: new index root position is returned here |
| 759 | * |
| 760 | * This function prepares the list of indexing nodes to commit and lays out |
| 761 | * their positions on flash. If there is not enough free space it uses the |
| 762 | * in-gap commit method. Returns zero in case of success and a negative error |
| 763 | * code in case of failure. |
| 764 | */ |
| 765 | int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot) |
| 766 | { |
| 767 | int err = 0, cnt; |
| 768 | |
| 769 | mutex_lock(&c->tnc_mutex); |
| 770 | err = dbg_check_tnc(c, 1); |
| 771 | if (err) |
| 772 | goto out; |
| 773 | cnt = get_znodes_to_commit(c); |
| 774 | if (cnt != 0) { |
| 775 | int no_space = 0; |
| 776 | |
| 777 | err = alloc_idx_lebs(c, cnt); |
| 778 | if (err == -ENOSPC) |
| 779 | no_space = 1; |
| 780 | else if (err) |
| 781 | goto out_free; |
| 782 | err = layout_commit(c, no_space, cnt); |
| 783 | if (err) |
| 784 | goto out_free; |
| 785 | ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0); |
| 786 | err = free_unused_idx_lebs(c); |
| 787 | if (err) |
| 788 | goto out; |
| 789 | } |
| 790 | destroy_old_idx(c); |
| 791 | memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch)); |
| 792 | |
| 793 | err = ubifs_save_dirty_idx_lnums(c); |
| 794 | if (err) |
| 795 | goto out; |
| 796 | |
| 797 | spin_lock(&c->space_lock); |
| 798 | /* |
| 799 | * Although we have not finished committing yet, update size of the |
| 800 | * committed index ('c->old_idx_sz') and zero out the index growth |
| 801 | * budget. It is OK to do this now, because we've reserved all the |
| 802 | * space which is needed to commit the index, and it is save for the |
| 803 | * budgeting subsystem to assume the index is already committed, |
| 804 | * even though it is not. |
| 805 | */ |
| 806 | c->old_idx_sz = c->calc_idx_sz; |
| 807 | c->budg_uncommitted_idx = 0; |
| 808 | spin_unlock(&c->space_lock); |
| 809 | mutex_unlock(&c->tnc_mutex); |
| 810 | |
| 811 | dbg_cmt("number of index LEBs %d", c->lst.idx_lebs); |
| 812 | dbg_cmt("size of index %llu", c->calc_idx_sz); |
| 813 | return err; |
| 814 | |
| 815 | out_free: |
| 816 | free_idx_lebs(c); |
| 817 | out: |
| 818 | mutex_unlock(&c->tnc_mutex); |
| 819 | return err; |
| 820 | } |
| 821 | |
| 822 | /** |
| 823 | * write_index - write index nodes. |
| 824 | * @c: UBIFS file-system description object |
| 825 | * |
| 826 | * This function writes the index nodes whose positions were laid out in the |
| 827 | * layout_in_empty_space function. |
| 828 | */ |
| 829 | static int write_index(struct ubifs_info *c) |
| 830 | { |
| 831 | struct ubifs_idx_node *idx; |
| 832 | struct ubifs_znode *znode, *cnext; |
| 833 | int i, lnum, offs, len, next_len, buf_len, buf_offs, used; |
| 834 | int avail, wlen, err, lnum_pos = 0; |
| 835 | |
| 836 | cnext = c->enext; |
| 837 | if (!cnext) |
| 838 | return 0; |
| 839 | |
| 840 | /* |
| 841 | * Always write index nodes to the index head so that index nodes and |
| 842 | * other types of nodes are never mixed in the same erase block. |
| 843 | */ |
| 844 | lnum = c->ihead_lnum; |
| 845 | buf_offs = c->ihead_offs; |
| 846 | |
| 847 | /* Allocate commit buffer */ |
| 848 | buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size); |
| 849 | used = 0; |
| 850 | avail = buf_len; |
| 851 | |
| 852 | /* Ensure there is enough room for first write */ |
| 853 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
| 854 | if (buf_offs + next_len > c->leb_size) { |
| 855 | err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0, |
| 856 | LPROPS_TAKEN); |
| 857 | if (err) |
| 858 | return err; |
| 859 | lnum = -1; |
| 860 | } |
| 861 | |
| 862 | while (1) { |
| 863 | cond_resched(); |
| 864 | |
| 865 | znode = cnext; |
| 866 | idx = c->cbuf + used; |
| 867 | |
| 868 | /* Make index node */ |
| 869 | idx->ch.node_type = UBIFS_IDX_NODE; |
| 870 | idx->child_cnt = cpu_to_le16(znode->child_cnt); |
| 871 | idx->level = cpu_to_le16(znode->level); |
| 872 | for (i = 0; i < znode->child_cnt; i++) { |
| 873 | struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); |
| 874 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; |
| 875 | |
| 876 | key_write_idx(c, &zbr->key, &br->key); |
| 877 | br->lnum = cpu_to_le32(zbr->lnum); |
| 878 | br->offs = cpu_to_le32(zbr->offs); |
| 879 | br->len = cpu_to_le32(zbr->len); |
| 880 | if (!zbr->lnum || !zbr->len) { |
| 881 | ubifs_err("bad ref in znode"); |
| 882 | dbg_dump_znode(c, znode); |
| 883 | if (zbr->znode) |
| 884 | dbg_dump_znode(c, zbr->znode); |
| 885 | } |
| 886 | } |
| 887 | len = ubifs_idx_node_sz(c, znode->child_cnt); |
| 888 | ubifs_prepare_node(c, idx, len, 0); |
| 889 | |
| 890 | /* Determine the index node position */ |
| 891 | if (lnum == -1) { |
| 892 | lnum = c->ilebs[lnum_pos++]; |
| 893 | buf_offs = 0; |
| 894 | used = 0; |
| 895 | avail = buf_len; |
| 896 | } |
| 897 | offs = buf_offs + used; |
| 898 | |
| 899 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 900 | if (lnum != znode->lnum || offs != znode->offs || |
| 901 | len != znode->len) { |
| 902 | ubifs_err("inconsistent znode posn"); |
| 903 | return -EINVAL; |
| 904 | } |
| 905 | #endif |
| 906 | |
| 907 | /* Grab some stuff from znode while we still can */ |
| 908 | cnext = znode->cnext; |
| 909 | |
| 910 | ubifs_assert(ubifs_zn_dirty(znode)); |
| 911 | ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); |
| 912 | |
| 913 | /* |
| 914 | * It is important that other threads should see %DIRTY_ZNODE |
| 915 | * flag cleared before %COW_ZNODE. Specifically, it matters in |
| 916 | * the 'dirty_cow_znode()' function. This is the reason for the |
| 917 | * first barrier. Also, we want the bit changes to be seen to |
| 918 | * other threads ASAP, to avoid unnecesarry copying, which is |
| 919 | * the reason for the second barrier. |
| 920 | */ |
| 921 | clear_bit(DIRTY_ZNODE, &znode->flags); |
| 922 | smp_mb__before_clear_bit(); |
| 923 | clear_bit(COW_ZNODE, &znode->flags); |
| 924 | smp_mb__after_clear_bit(); |
| 925 | |
| 926 | /* Do not access znode from this point on */ |
| 927 | |
| 928 | /* Update buffer positions */ |
| 929 | wlen = used + len; |
| 930 | used += ALIGN(len, 8); |
| 931 | avail -= ALIGN(len, 8); |
| 932 | |
| 933 | /* |
| 934 | * Calculate the next index node length to see if there is |
| 935 | * enough room for it |
| 936 | */ |
| 937 | if (cnext == c->cnext) |
| 938 | next_len = 0; |
| 939 | else |
| 940 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
| 941 | |
| 942 | if (c->min_io_size == 1) { |
| 943 | /* |
| 944 | * Write the prepared index node immediately if there is |
| 945 | * no minimum IO size |
| 946 | */ |
| 947 | err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, |
| 948 | wlen, UBI_SHORTTERM); |
| 949 | if (err) |
| 950 | return err; |
| 951 | buf_offs += ALIGN(wlen, 8); |
| 952 | if (next_len) { |
| 953 | used = 0; |
| 954 | avail = buf_len; |
| 955 | if (buf_offs + next_len > c->leb_size) { |
| 956 | err = ubifs_update_one_lp(c, lnum, |
| 957 | LPROPS_NC, 0, 0, LPROPS_TAKEN); |
| 958 | if (err) |
| 959 | return err; |
| 960 | lnum = -1; |
| 961 | } |
| 962 | continue; |
| 963 | } |
| 964 | } else { |
| 965 | int blen, nxt_offs = buf_offs + used + next_len; |
| 966 | |
| 967 | if (next_len && nxt_offs <= c->leb_size) { |
| 968 | if (avail > 0) |
| 969 | continue; |
| 970 | else |
| 971 | blen = buf_len; |
| 972 | } else { |
| 973 | wlen = ALIGN(wlen, 8); |
| 974 | blen = ALIGN(wlen, c->min_io_size); |
| 975 | ubifs_pad(c, c->cbuf + wlen, blen - wlen); |
| 976 | } |
| 977 | /* |
| 978 | * The buffer is full or there are no more znodes |
| 979 | * to do |
| 980 | */ |
| 981 | err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, |
| 982 | blen, UBI_SHORTTERM); |
| 983 | if (err) |
| 984 | return err; |
| 985 | buf_offs += blen; |
| 986 | if (next_len) { |
| 987 | if (nxt_offs > c->leb_size) { |
| 988 | err = ubifs_update_one_lp(c, lnum, |
| 989 | LPROPS_NC, 0, 0, LPROPS_TAKEN); |
| 990 | if (err) |
| 991 | return err; |
| 992 | lnum = -1; |
| 993 | } |
| 994 | used -= blen; |
| 995 | if (used < 0) |
| 996 | used = 0; |
| 997 | avail = buf_len - used; |
| 998 | memmove(c->cbuf, c->cbuf + blen, used); |
| 999 | continue; |
| 1000 | } |
| 1001 | } |
| 1002 | break; |
| 1003 | } |
| 1004 | |
| 1005 | #ifdef CONFIG_UBIFS_FS_DEBUG |
| 1006 | if (lnum != c->new_ihead_lnum || buf_offs != c->new_ihead_offs) { |
| 1007 | ubifs_err("inconsistent ihead"); |
| 1008 | return -EINVAL; |
| 1009 | } |
| 1010 | #endif |
| 1011 | |
| 1012 | c->ihead_lnum = lnum; |
| 1013 | c->ihead_offs = buf_offs; |
| 1014 | |
| 1015 | return 0; |
| 1016 | } |
| 1017 | |
| 1018 | /** |
| 1019 | * free_obsolete_znodes - free obsolete znodes. |
| 1020 | * @c: UBIFS file-system description object |
| 1021 | * |
| 1022 | * At the end of commit end, obsolete znodes are freed. |
| 1023 | */ |
| 1024 | static void free_obsolete_znodes(struct ubifs_info *c) |
| 1025 | { |
| 1026 | struct ubifs_znode *znode, *cnext; |
| 1027 | |
| 1028 | cnext = c->cnext; |
| 1029 | do { |
| 1030 | znode = cnext; |
| 1031 | cnext = znode->cnext; |
| 1032 | if (test_bit(OBSOLETE_ZNODE, &znode->flags)) |
| 1033 | kfree(znode); |
| 1034 | else { |
| 1035 | znode->cnext = NULL; |
| 1036 | atomic_long_inc(&c->clean_zn_cnt); |
| 1037 | atomic_long_inc(&ubifs_clean_zn_cnt); |
| 1038 | } |
| 1039 | } while (cnext != c->cnext); |
| 1040 | } |
| 1041 | |
| 1042 | /** |
| 1043 | * return_gap_lebs - return LEBs used by the in-gap commit method. |
| 1044 | * @c: UBIFS file-system description object |
| 1045 | * |
| 1046 | * This function clears the "taken" flag for the LEBs which were used by the |
| 1047 | * "commit in-the-gaps" method. |
| 1048 | */ |
| 1049 | static int return_gap_lebs(struct ubifs_info *c) |
| 1050 | { |
| 1051 | int *p, err; |
| 1052 | |
| 1053 | if (!c->gap_lebs) |
| 1054 | return 0; |
| 1055 | |
| 1056 | dbg_cmt(""); |
| 1057 | for (p = c->gap_lebs; *p != -1; p++) { |
| 1058 | err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0, |
| 1059 | LPROPS_TAKEN, 0); |
| 1060 | if (err) |
| 1061 | return err; |
| 1062 | } |
| 1063 | |
| 1064 | kfree(c->gap_lebs); |
| 1065 | c->gap_lebs = NULL; |
| 1066 | return 0; |
| 1067 | } |
| 1068 | |
| 1069 | /** |
| 1070 | * ubifs_tnc_end_commit - update the TNC for commit end. |
| 1071 | * @c: UBIFS file-system description object |
| 1072 | * |
| 1073 | * Write the dirty znodes. |
| 1074 | */ |
| 1075 | int ubifs_tnc_end_commit(struct ubifs_info *c) |
| 1076 | { |
| 1077 | int err; |
| 1078 | |
| 1079 | if (!c->cnext) |
| 1080 | return 0; |
| 1081 | |
| 1082 | err = return_gap_lebs(c); |
| 1083 | if (err) |
| 1084 | return err; |
| 1085 | |
| 1086 | err = write_index(c); |
| 1087 | if (err) |
| 1088 | return err; |
| 1089 | |
| 1090 | mutex_lock(&c->tnc_mutex); |
| 1091 | |
| 1092 | dbg_cmt("TNC height is %d", c->zroot.znode->level + 1); |
| 1093 | |
| 1094 | free_obsolete_znodes(c); |
| 1095 | |
| 1096 | c->cnext = NULL; |
| 1097 | kfree(c->ilebs); |
| 1098 | c->ilebs = NULL; |
| 1099 | |
| 1100 | mutex_unlock(&c->tnc_mutex); |
| 1101 | |
| 1102 | return 0; |
| 1103 | } |