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