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 XFS_ERROR(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 XFS_ERROR(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 = XFS_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 XFS_ERROR(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 XFS_ERROR(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 = XFS_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 error = xfs_dir_canenter(tp, dp, link_name, resblks); 273 if (error) 274 goto error_return; 275 /* 276 * Initialize the bmap freelist prior to calling either 277 * bmapi or the directory create code. 278 */ 279 xfs_bmap_init(&free_list, &first_block); 280 281 /* 282 * Allocate an inode for the symlink. 283 */ 284 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 285 prid, resblks > 0, &ip, NULL); 286 if (error) { 287 if (error == ENOSPC) 288 goto error_return; 289 goto error1; 290 } 291 292 /* 293 * An error after we've joined dp to the transaction will result in the 294 * transaction cancel unlocking dp so don't do it explicitly in the 295 * error path. 296 */ 297 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); 298 unlock_dp_on_error = false; 299 300 /* 301 * Also attach the dquot(s) to it, if applicable. 302 */ 303 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 304 305 if (resblks) 306 resblks -= XFS_IALLOC_SPACE_RES(mp); 307 /* 308 * If the symlink will fit into the inode, write it inline. 309 */ 310 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 311 xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK); 312 memcpy(ip->i_df.if_u1.if_data, target_path, pathlen); 313 ip->i_d.di_size = pathlen; 314 315 /* 316 * The inode was initially created in extent format. 317 */ 318 ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT); 319 ip->i_df.if_flags |= XFS_IFINLINE; 320 321 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 322 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 323 324 } else { 325 int offset; 326 327 first_fsb = 0; 328 nmaps = XFS_SYMLINK_MAPS; 329 330 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 331 XFS_BMAPI_METADATA, &first_block, resblks, 332 mval, &nmaps, &free_list); 333 if (error) 334 goto error2; 335 336 if (resblks) 337 resblks -= fs_blocks; 338 ip->i_d.di_size = pathlen; 339 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 340 341 cur_chunk = target_path; 342 offset = 0; 343 for (n = 0; n < nmaps; n++) { 344 char *buf; 345 346 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 347 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 348 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 349 BTOBB(byte_cnt), 0); 350 if (!bp) { 351 error = ENOMEM; 352 goto error2; 353 } 354 bp->b_ops = &xfs_symlink_buf_ops; 355 356 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 357 byte_cnt = min(byte_cnt, pathlen); 358 359 buf = bp->b_addr; 360 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 361 byte_cnt, bp); 362 363 memcpy(buf, cur_chunk, byte_cnt); 364 365 cur_chunk += byte_cnt; 366 pathlen -= byte_cnt; 367 offset += byte_cnt; 368 369 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 370 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 371 (char *)bp->b_addr); 372 } 373 ASSERT(pathlen == 0); 374 } 375 376 /* 377 * Create the directory entry for the symlink. 378 */ 379 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 380 &first_block, &free_list, resblks); 381 if (error) 382 goto error2; 383 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 384 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 385 386 /* 387 * If this is a synchronous mount, make sure that the 388 * symlink transaction goes to disk before returning to 389 * the user. 390 */ 391 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 392 xfs_trans_set_sync(tp); 393 } 394 395 error = xfs_bmap_finish(&tp, &free_list, &committed); 396 if (error) { 397 goto error2; 398 } 399 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 400 xfs_qm_dqrele(udqp); 401 xfs_qm_dqrele(gdqp); 402 xfs_qm_dqrele(pdqp); 403 404 *ipp = ip; 405 return 0; 406 407 error2: 408 IRELE(ip); 409 error1: 410 xfs_bmap_cancel(&free_list); 411 cancel_flags |= XFS_TRANS_ABORT; 412 error_return: 413 xfs_trans_cancel(tp, cancel_flags); 414 xfs_qm_dqrele(udqp); 415 xfs_qm_dqrele(gdqp); 416 xfs_qm_dqrele(pdqp); 417 418 if (unlock_dp_on_error) 419 xfs_iunlock(dp, XFS_ILOCK_EXCL); 420 std_return: 421 return error; 422 } 423 424 /* 425 * Free a symlink that has blocks associated with it. 426 */ 427 STATIC int 428 xfs_inactive_symlink_rmt( 429 struct xfs_inode *ip) 430 { 431 xfs_buf_t *bp; 432 int committed; 433 int done; 434 int error; 435 xfs_fsblock_t first_block; 436 xfs_bmap_free_t free_list; 437 int i; 438 xfs_mount_t *mp; 439 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 440 int nmaps; 441 int size; 442 xfs_trans_t *tp; 443 444 mp = ip->i_mount; 445 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 446 /* 447 * We're freeing a symlink that has some 448 * blocks allocated to it. Free the 449 * blocks here. We know that we've got 450 * either 1 or 2 extents and that we can 451 * free them all in one bunmapi call. 452 */ 453 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 454 455 tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE); 456 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0); 457 if (error) { 458 xfs_trans_cancel(tp, 0); 459 return error; 460 } 461 462 xfs_ilock(ip, XFS_ILOCK_EXCL); 463 xfs_trans_ijoin(tp, ip, 0); 464 465 /* 466 * Lock the inode, fix the size, and join it to the transaction. 467 * Hold it so in the normal path, we still have it locked for 468 * the second transaction. In the error paths we need it 469 * held so the cancel won't rele it, see below. 470 */ 471 size = (int)ip->i_d.di_size; 472 ip->i_d.di_size = 0; 473 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 474 /* 475 * Find the block(s) so we can inval and unmap them. 476 */ 477 done = 0; 478 xfs_bmap_init(&free_list, &first_block); 479 nmaps = ARRAY_SIZE(mval); 480 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 481 mval, &nmaps, 0); 482 if (error) 483 goto error_trans_cancel; 484 /* 485 * Invalidate the block(s). No validation is done. 486 */ 487 for (i = 0; i < nmaps; i++) { 488 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 489 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 490 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 491 if (!bp) { 492 error = ENOMEM; 493 goto error_bmap_cancel; 494 } 495 xfs_trans_binval(tp, bp); 496 } 497 /* 498 * Unmap the dead block(s) to the free_list. 499 */ 500 error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps, 501 &first_block, &free_list, &done); 502 if (error) 503 goto error_bmap_cancel; 504 ASSERT(done); 505 /* 506 * Commit the first transaction. This logs the EFI and the inode. 507 */ 508 error = xfs_bmap_finish(&tp, &free_list, &committed); 509 if (error) 510 goto error_bmap_cancel; 511 /* 512 * The transaction must have been committed, since there were 513 * actually extents freed by xfs_bunmapi. See xfs_bmap_finish. 514 * The new tp has the extent freeing and EFDs. 515 */ 516 ASSERT(committed); 517 /* 518 * The first xact was committed, so add the inode to the new one. 519 * Mark it dirty so it will be logged and moved forward in the log as 520 * part of every commit. 521 */ 522 xfs_trans_ijoin(tp, ip, 0); 523 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 524 /* 525 * Commit the transaction containing extent freeing and EFDs. 526 */ 527 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 528 if (error) { 529 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 530 goto error_unlock; 531 } 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 xfs_iunlock(ip, XFS_ILOCK_EXCL); 541 return 0; 542 543 error_bmap_cancel: 544 xfs_bmap_cancel(&free_list); 545 error_trans_cancel: 546 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT); 547 error_unlock: 548 xfs_iunlock(ip, XFS_ILOCK_EXCL); 549 return error; 550 } 551 552 /* 553 * xfs_inactive_symlink - free a symlink 554 */ 555 int 556 xfs_inactive_symlink( 557 struct xfs_inode *ip) 558 { 559 struct xfs_mount *mp = ip->i_mount; 560 int pathlen; 561 562 trace_xfs_inactive_symlink(ip); 563 564 if (XFS_FORCED_SHUTDOWN(mp)) 565 return XFS_ERROR(EIO); 566 567 xfs_ilock(ip, XFS_ILOCK_EXCL); 568 569 /* 570 * Zero length symlinks _can_ exist. 571 */ 572 pathlen = (int)ip->i_d.di_size; 573 if (!pathlen) { 574 xfs_iunlock(ip, XFS_ILOCK_EXCL); 575 return 0; 576 } 577 578 if (pathlen < 0 || pathlen > MAXPATHLEN) { 579 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 580 __func__, (unsigned long long)ip->i_ino, pathlen); 581 xfs_iunlock(ip, XFS_ILOCK_EXCL); 582 ASSERT(0); 583 return XFS_ERROR(EFSCORRUPTED); 584 } 585 586 if (ip->i_df.if_flags & XFS_IFINLINE) { 587 if (ip->i_df.if_bytes > 0) 588 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 589 XFS_DATA_FORK); 590 xfs_iunlock(ip, XFS_ILOCK_EXCL); 591 ASSERT(ip->i_df.if_bytes == 0); 592 return 0; 593 } 594 595 xfs_iunlock(ip, XFS_ILOCK_EXCL); 596 597 /* remove the remote symlink */ 598 return xfs_inactive_symlink_rmt(ip); 599 } 600