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