1 /* 2 * Copyright (c) 2000-2006 Silicon Graphics, Inc. 3 * Copyright (c) 2012-2013 Red Hat, Inc. 4 * All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it would be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 */ 19 #include "xfs.h" 20 #include "xfs_fs.h" 21 #include "xfs_format.h" 22 #include "xfs_bit.h" 23 #include "xfs_log.h" 24 #include "xfs_trans.h" 25 #include "xfs_sb.h" 26 #include "xfs_ag.h" 27 #include "xfs_mount.h" 28 #include "xfs_da_btree.h" 29 #include "xfs_dir2_format.h" 30 #include "xfs_dir2.h" 31 #include "xfs_bmap_btree.h" 32 #include "xfs_ialloc_btree.h" 33 #include "xfs_dinode.h" 34 #include "xfs_inode.h" 35 #include "xfs_ialloc.h" 36 #include "xfs_alloc.h" 37 #include "xfs_bmap.h" 38 #include "xfs_bmap_util.h" 39 #include "xfs_error.h" 40 #include "xfs_quota.h" 41 #include "xfs_trans_space.h" 42 #include "xfs_trace.h" 43 #include "xfs_symlink.h" 44 45 /* ----- Kernel only functions below ----- */ 46 STATIC int 47 xfs_readlink_bmap( 48 struct xfs_inode *ip, 49 char *link) 50 { 51 struct xfs_mount *mp = ip->i_mount; 52 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 53 struct xfs_buf *bp; 54 xfs_daddr_t d; 55 char *cur_chunk; 56 int pathlen = ip->i_d.di_size; 57 int nmaps = XFS_SYMLINK_MAPS; 58 int byte_cnt; 59 int n; 60 int error = 0; 61 int fsblocks = 0; 62 int offset; 63 64 fsblocks = xfs_symlink_blocks(mp, pathlen); 65 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); 66 if (error) 67 goto out; 68 69 offset = 0; 70 for (n = 0; n < nmaps; n++) { 71 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 72 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 73 74 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, 75 &xfs_symlink_buf_ops); 76 if (!bp) 77 return XFS_ERROR(ENOMEM); 78 error = bp->b_error; 79 if (error) { 80 xfs_buf_ioerror_alert(bp, __func__); 81 xfs_buf_relse(bp); 82 goto out; 83 } 84 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 85 if (pathlen < byte_cnt) 86 byte_cnt = pathlen; 87 88 cur_chunk = bp->b_addr; 89 if (xfs_sb_version_hascrc(&mp->m_sb)) { 90 if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset, 91 byte_cnt, bp)) { 92 error = EFSCORRUPTED; 93 xfs_alert(mp, 94 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)", 95 offset, byte_cnt, ip->i_ino); 96 xfs_buf_relse(bp); 97 goto out; 98 99 } 100 101 cur_chunk += sizeof(struct xfs_dsymlink_hdr); 102 } 103 104 memcpy(link + offset, bp->b_addr, byte_cnt); 105 106 pathlen -= byte_cnt; 107 offset += byte_cnt; 108 109 xfs_buf_relse(bp); 110 } 111 ASSERT(pathlen == 0); 112 113 link[ip->i_d.di_size] = '\0'; 114 error = 0; 115 116 out: 117 return error; 118 } 119 120 int 121 xfs_readlink( 122 struct xfs_inode *ip, 123 char *link) 124 { 125 struct xfs_mount *mp = ip->i_mount; 126 xfs_fsize_t pathlen; 127 int error = 0; 128 129 trace_xfs_readlink(ip); 130 131 if (XFS_FORCED_SHUTDOWN(mp)) 132 return XFS_ERROR(EIO); 133 134 xfs_ilock(ip, XFS_ILOCK_SHARED); 135 136 pathlen = ip->i_d.di_size; 137 if (!pathlen) 138 goto out; 139 140 if (pathlen < 0 || pathlen > MAXPATHLEN) { 141 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", 142 __func__, (unsigned long long) ip->i_ino, 143 (long long) pathlen); 144 ASSERT(0); 145 error = XFS_ERROR(EFSCORRUPTED); 146 goto out; 147 } 148 149 150 if (ip->i_df.if_flags & XFS_IFINLINE) { 151 memcpy(link, ip->i_df.if_u1.if_data, pathlen); 152 link[pathlen] = '\0'; 153 } else { 154 error = xfs_readlink_bmap(ip, link); 155 } 156 157 out: 158 xfs_iunlock(ip, XFS_ILOCK_SHARED); 159 return error; 160 } 161 162 int 163 xfs_symlink( 164 struct xfs_inode *dp, 165 struct xfs_name *link_name, 166 const char *target_path, 167 umode_t mode, 168 struct xfs_inode **ipp) 169 { 170 struct xfs_mount *mp = dp->i_mount; 171 struct xfs_trans *tp = NULL; 172 struct xfs_inode *ip = NULL; 173 int error = 0; 174 int pathlen; 175 struct xfs_bmap_free free_list; 176 xfs_fsblock_t first_block; 177 bool unlock_dp_on_error = false; 178 uint cancel_flags; 179 int committed; 180 xfs_fileoff_t first_fsb; 181 xfs_filblks_t fs_blocks; 182 int nmaps; 183 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 184 xfs_daddr_t d; 185 const char *cur_chunk; 186 int byte_cnt; 187 int n; 188 xfs_buf_t *bp; 189 prid_t prid; 190 struct xfs_dquot *udqp = NULL; 191 struct xfs_dquot *gdqp = NULL; 192 struct xfs_dquot *pdqp = NULL; 193 uint resblks; 194 195 *ipp = NULL; 196 197 trace_xfs_symlink(dp, link_name); 198 199 if (XFS_FORCED_SHUTDOWN(mp)) 200 return XFS_ERROR(EIO); 201 202 /* 203 * Check component lengths of the target path name. 204 */ 205 pathlen = strlen(target_path); 206 if (pathlen >= MAXPATHLEN) /* total string too long */ 207 return XFS_ERROR(ENAMETOOLONG); 208 209 udqp = gdqp = NULL; 210 if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) 211 prid = xfs_get_projid(dp); 212 else 213 prid = XFS_PROJID_DEFAULT; 214 215 /* 216 * Make sure that we have allocated dquot(s) on disk. 217 */ 218 error = xfs_qm_vop_dqalloc(dp, 219 xfs_kuid_to_uid(current_fsuid()), 220 xfs_kgid_to_gid(current_fsgid()), prid, 221 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 222 &udqp, &gdqp, &pdqp); 223 if (error) 224 goto std_return; 225 226 tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK); 227 cancel_flags = XFS_TRANS_RELEASE_LOG_RES; 228 /* 229 * The symlink will fit into the inode data fork? 230 * There can't be any attributes so we get the whole variable part. 231 */ 232 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 233 fs_blocks = 0; 234 else 235 fs_blocks = xfs_symlink_blocks(mp, pathlen); 236 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 237 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0); 238 if (error == ENOSPC && fs_blocks == 0) { 239 resblks = 0; 240 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0); 241 } 242 if (error) { 243 cancel_flags = 0; 244 goto error_return; 245 } 246 247 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); 248 unlock_dp_on_error = true; 249 250 /* 251 * Check whether the directory allows new symlinks or not. 252 */ 253 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) { 254 error = XFS_ERROR(EPERM); 255 goto error_return; 256 } 257 258 /* 259 * Reserve disk quota : blocks and inode. 260 */ 261 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, 262 pdqp, resblks, 1, 0); 263 if (error) 264 goto error_return; 265 266 /* 267 * Check for ability to enter directory entry, if no space reserved. 268 */ 269 error = xfs_dir_canenter(tp, dp, link_name, resblks); 270 if (error) 271 goto error_return; 272 /* 273 * Initialize the bmap freelist prior to calling either 274 * bmapi or the directory create code. 275 */ 276 xfs_bmap_init(&free_list, &first_block); 277 278 /* 279 * Allocate an inode for the symlink. 280 */ 281 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 282 prid, resblks > 0, &ip, NULL); 283 if (error) { 284 if (error == ENOSPC) 285 goto error_return; 286 goto error1; 287 } 288 289 /* 290 * An error after we've joined dp to the transaction will result in the 291 * transaction cancel unlocking dp so don't do it explicitly in the 292 * error path. 293 */ 294 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); 295 unlock_dp_on_error = false; 296 297 /* 298 * Also attach the dquot(s) to it, if applicable. 299 */ 300 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 301 302 if (resblks) 303 resblks -= XFS_IALLOC_SPACE_RES(mp); 304 /* 305 * If the symlink will fit into the inode, write it inline. 306 */ 307 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 308 xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK); 309 memcpy(ip->i_df.if_u1.if_data, target_path, pathlen); 310 ip->i_d.di_size = pathlen; 311 312 /* 313 * The inode was initially created in extent format. 314 */ 315 ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT); 316 ip->i_df.if_flags |= XFS_IFINLINE; 317 318 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 319 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 320 321 } else { 322 int offset; 323 324 first_fsb = 0; 325 nmaps = XFS_SYMLINK_MAPS; 326 327 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 328 XFS_BMAPI_METADATA, &first_block, resblks, 329 mval, &nmaps, &free_list); 330 if (error) 331 goto error2; 332 333 if (resblks) 334 resblks -= fs_blocks; 335 ip->i_d.di_size = pathlen; 336 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 337 338 cur_chunk = target_path; 339 offset = 0; 340 for (n = 0; n < nmaps; n++) { 341 char *buf; 342 343 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 344 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 345 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 346 BTOBB(byte_cnt), 0); 347 if (!bp) { 348 error = ENOMEM; 349 goto error2; 350 } 351 bp->b_ops = &xfs_symlink_buf_ops; 352 353 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 354 byte_cnt = min(byte_cnt, pathlen); 355 356 buf = bp->b_addr; 357 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 358 byte_cnt, bp); 359 360 memcpy(buf, cur_chunk, byte_cnt); 361 362 cur_chunk += byte_cnt; 363 pathlen -= byte_cnt; 364 offset += byte_cnt; 365 366 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 367 (char *)bp->b_addr); 368 } 369 ASSERT(pathlen == 0); 370 } 371 372 /* 373 * Create the directory entry for the symlink. 374 */ 375 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 376 &first_block, &free_list, resblks); 377 if (error) 378 goto error2; 379 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 380 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 381 382 /* 383 * If this is a synchronous mount, make sure that the 384 * symlink transaction goes to disk before returning to 385 * the user. 386 */ 387 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 388 xfs_trans_set_sync(tp); 389 } 390 391 error = xfs_bmap_finish(&tp, &free_list, &committed); 392 if (error) { 393 goto error2; 394 } 395 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 396 xfs_qm_dqrele(udqp); 397 xfs_qm_dqrele(gdqp); 398 xfs_qm_dqrele(pdqp); 399 400 *ipp = ip; 401 return 0; 402 403 error2: 404 IRELE(ip); 405 error1: 406 xfs_bmap_cancel(&free_list); 407 cancel_flags |= XFS_TRANS_ABORT; 408 error_return: 409 xfs_trans_cancel(tp, cancel_flags); 410 xfs_qm_dqrele(udqp); 411 xfs_qm_dqrele(gdqp); 412 xfs_qm_dqrele(pdqp); 413 414 if (unlock_dp_on_error) 415 xfs_iunlock(dp, XFS_ILOCK_EXCL); 416 std_return: 417 return error; 418 } 419 420 /* 421 * Free a symlink that has blocks associated with it. 422 */ 423 STATIC int 424 xfs_inactive_symlink_rmt( 425 xfs_inode_t *ip, 426 xfs_trans_t **tpp) 427 { 428 xfs_buf_t *bp; 429 int committed; 430 int done; 431 int error; 432 xfs_fsblock_t first_block; 433 xfs_bmap_free_t free_list; 434 int i; 435 xfs_mount_t *mp; 436 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 437 int nmaps; 438 xfs_trans_t *ntp; 439 int size; 440 xfs_trans_t *tp; 441 442 tp = *tpp; 443 mp = ip->i_mount; 444 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 445 /* 446 * We're freeing a symlink that has some 447 * blocks allocated to it. Free the 448 * blocks here. We know that we've got 449 * either 1 or 2 extents and that we can 450 * free them all in one bunmapi call. 451 */ 452 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 453 454 /* 455 * Lock the inode, fix the size, and join it to the transaction. 456 * Hold it so in the normal path, we still have it locked for 457 * the second transaction. In the error paths we need it 458 * held so the cancel won't rele it, see below. 459 */ 460 size = (int)ip->i_d.di_size; 461 ip->i_d.di_size = 0; 462 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 463 /* 464 * Find the block(s) so we can inval and unmap them. 465 */ 466 done = 0; 467 xfs_bmap_init(&free_list, &first_block); 468 nmaps = ARRAY_SIZE(mval); 469 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 470 mval, &nmaps, 0); 471 if (error) 472 goto error0; 473 /* 474 * Invalidate the block(s). No validation is done. 475 */ 476 for (i = 0; i < nmaps; i++) { 477 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 478 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 479 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 480 if (!bp) { 481 error = ENOMEM; 482 goto error1; 483 } 484 xfs_trans_binval(tp, bp); 485 } 486 /* 487 * Unmap the dead block(s) to the free_list. 488 */ 489 if ((error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps, 490 &first_block, &free_list, &done))) 491 goto error1; 492 ASSERT(done); 493 /* 494 * Commit the first transaction. This logs the EFI and the inode. 495 */ 496 if ((error = xfs_bmap_finish(&tp, &free_list, &committed))) 497 goto error1; 498 /* 499 * The transaction must have been committed, since there were 500 * actually extents freed by xfs_bunmapi. See xfs_bmap_finish. 501 * The new tp has the extent freeing and EFDs. 502 */ 503 ASSERT(committed); 504 /* 505 * The first xact was committed, so add the inode to the new one. 506 * Mark it dirty so it will be logged and moved forward in the log as 507 * part of every commit. 508 */ 509 xfs_trans_ijoin(tp, ip, 0); 510 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 511 /* 512 * Get a new, empty transaction to return to our caller. 513 */ 514 ntp = xfs_trans_dup(tp); 515 /* 516 * Commit the transaction containing extent freeing and EFDs. 517 * If we get an error on the commit here or on the reserve below, 518 * we need to unlock the inode since the new transaction doesn't 519 * have the inode attached. 520 */ 521 error = xfs_trans_commit(tp, 0); 522 tp = ntp; 523 if (error) { 524 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 525 goto error0; 526 } 527 /* 528 * transaction commit worked ok so we can drop the extra ticket 529 * reference that we gained in xfs_trans_dup() 530 */ 531 xfs_log_ticket_put(tp->t_ticket); 532 533 /* 534 * Remove the memory for extent descriptions (just bookkeeping). 535 */ 536 if (ip->i_df.if_bytes) 537 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 538 ASSERT(ip->i_df.if_bytes == 0); 539 /* 540 * Put an itruncate log reservation in the new transaction 541 * for our caller. 542 */ 543 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0); 544 if (error) { 545 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 546 goto error0; 547 } 548 549 xfs_trans_ijoin(tp, ip, 0); 550 *tpp = tp; 551 return 0; 552 553 error1: 554 xfs_bmap_cancel(&free_list); 555 error0: 556 return error; 557 } 558 559 /* 560 * xfs_inactive_symlink - free a symlink 561 */ 562 int 563 xfs_inactive_symlink( 564 struct xfs_inode *ip, 565 struct xfs_trans **tp) 566 { 567 struct xfs_mount *mp = ip->i_mount; 568 int pathlen; 569 570 trace_xfs_inactive_symlink(ip); 571 572 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); 573 574 if (XFS_FORCED_SHUTDOWN(mp)) 575 return XFS_ERROR(EIO); 576 577 /* 578 * Zero length symlinks _can_ exist. 579 */ 580 pathlen = (int)ip->i_d.di_size; 581 if (!pathlen) 582 return 0; 583 584 if (pathlen < 0 || pathlen > MAXPATHLEN) { 585 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 586 __func__, (unsigned long long)ip->i_ino, pathlen); 587 ASSERT(0); 588 return XFS_ERROR(EFSCORRUPTED); 589 } 590 591 if (ip->i_df.if_flags & XFS_IFINLINE) { 592 if (ip->i_df.if_bytes > 0) 593 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 594 XFS_DATA_FORK); 595 ASSERT(ip->i_df.if_bytes == 0); 596 return 0; 597 } 598 599 /* remove the remote symlink */ 600 return xfs_inactive_symlink_rmt(ip, tp); 601 } 602