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_dir2.h" 31 #include "xfs_inode.h" 32 #include "xfs_ialloc.h" 33 #include "xfs_alloc.h" 34 #include "xfs_bmap.h" 35 #include "xfs_bmap_btree.h" 36 #include "xfs_bmap_util.h" 37 #include "xfs_error.h" 38 #include "xfs_quota.h" 39 #include "xfs_trans_space.h" 40 #include "xfs_trace.h" 41 #include "xfs_symlink.h" 42 #include "xfs_trans.h" 43 #include "xfs_log.h" 44 #include "xfs_dinode.h" 45 46 /* ----- Kernel only functions below ----- */ 47 STATIC int 48 xfs_readlink_bmap( 49 struct xfs_inode *ip, 50 char *link) 51 { 52 struct xfs_mount *mp = ip->i_mount; 53 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 54 struct xfs_buf *bp; 55 xfs_daddr_t d; 56 char *cur_chunk; 57 int pathlen = ip->i_d.di_size; 58 int nmaps = XFS_SYMLINK_MAPS; 59 int byte_cnt; 60 int n; 61 int error = 0; 62 int fsblocks = 0; 63 int offset; 64 65 fsblocks = xfs_symlink_blocks(mp, pathlen); 66 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); 67 if (error) 68 goto out; 69 70 offset = 0; 71 for (n = 0; n < nmaps; n++) { 72 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 73 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 74 75 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, 76 &xfs_symlink_buf_ops); 77 if (!bp) 78 return XFS_ERROR(ENOMEM); 79 error = bp->b_error; 80 if (error) { 81 xfs_buf_ioerror_alert(bp, __func__); 82 xfs_buf_relse(bp); 83 goto out; 84 } 85 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 86 if (pathlen < byte_cnt) 87 byte_cnt = pathlen; 88 89 cur_chunk = bp->b_addr; 90 if (xfs_sb_version_hascrc(&mp->m_sb)) { 91 if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset, 92 byte_cnt, bp)) { 93 error = EFSCORRUPTED; 94 xfs_alert(mp, 95 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)", 96 offset, byte_cnt, ip->i_ino); 97 xfs_buf_relse(bp); 98 goto out; 99 100 } 101 102 cur_chunk += sizeof(struct xfs_dsymlink_hdr); 103 } 104 105 memcpy(link + offset, bp->b_addr, byte_cnt); 106 107 pathlen -= byte_cnt; 108 offset += byte_cnt; 109 110 xfs_buf_relse(bp); 111 } 112 ASSERT(pathlen == 0); 113 114 link[ip->i_d.di_size] = '\0'; 115 error = 0; 116 117 out: 118 return error; 119 } 120 121 int 122 xfs_readlink( 123 struct xfs_inode *ip, 124 char *link) 125 { 126 struct xfs_mount *mp = ip->i_mount; 127 xfs_fsize_t pathlen; 128 int error = 0; 129 130 trace_xfs_readlink(ip); 131 132 if (XFS_FORCED_SHUTDOWN(mp)) 133 return XFS_ERROR(EIO); 134 135 xfs_ilock(ip, XFS_ILOCK_SHARED); 136 137 pathlen = ip->i_d.di_size; 138 if (!pathlen) 139 goto out; 140 141 if (pathlen < 0 || pathlen > MAXPATHLEN) { 142 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", 143 __func__, (unsigned long long) ip->i_ino, 144 (long long) pathlen); 145 ASSERT(0); 146 error = XFS_ERROR(EFSCORRUPTED); 147 goto out; 148 } 149 150 151 if (ip->i_df.if_flags & XFS_IFINLINE) { 152 memcpy(link, ip->i_df.if_u1.if_data, pathlen); 153 link[pathlen] = '\0'; 154 } else { 155 error = xfs_readlink_bmap(ip, link); 156 } 157 158 out: 159 xfs_iunlock(ip, XFS_ILOCK_SHARED); 160 return error; 161 } 162 163 int 164 xfs_symlink( 165 struct xfs_inode *dp, 166 struct xfs_name *link_name, 167 const char *target_path, 168 umode_t mode, 169 struct xfs_inode **ipp) 170 { 171 struct xfs_mount *mp = dp->i_mount; 172 struct xfs_trans *tp = NULL; 173 struct xfs_inode *ip = NULL; 174 int error = 0; 175 int pathlen; 176 struct xfs_bmap_free free_list; 177 xfs_fsblock_t first_block; 178 bool unlock_dp_on_error = false; 179 uint cancel_flags; 180 int committed; 181 xfs_fileoff_t first_fsb; 182 xfs_filblks_t fs_blocks; 183 int nmaps; 184 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 185 xfs_daddr_t d; 186 const char *cur_chunk; 187 int byte_cnt; 188 int n; 189 xfs_buf_t *bp; 190 prid_t prid; 191 struct xfs_dquot *udqp = NULL; 192 struct xfs_dquot *gdqp = NULL; 193 struct xfs_dquot *pdqp = NULL; 194 uint resblks; 195 196 *ipp = NULL; 197 198 trace_xfs_symlink(dp, link_name); 199 200 if (XFS_FORCED_SHUTDOWN(mp)) 201 return XFS_ERROR(EIO); 202 203 /* 204 * Check component lengths of the target path name. 205 */ 206 pathlen = strlen(target_path); 207 if (pathlen >= MAXPATHLEN) /* total string too long */ 208 return XFS_ERROR(ENAMETOOLONG); 209 210 udqp = gdqp = NULL; 211 if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) 212 prid = xfs_get_projid(dp); 213 else 214 prid = XFS_PROJID_DEFAULT; 215 216 /* 217 * Make sure that we have allocated dquot(s) on disk. 218 */ 219 error = xfs_qm_vop_dqalloc(dp, 220 xfs_kuid_to_uid(current_fsuid()), 221 xfs_kgid_to_gid(current_fsgid()), prid, 222 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 223 &udqp, &gdqp, &pdqp); 224 if (error) 225 goto std_return; 226 227 tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK); 228 cancel_flags = XFS_TRANS_RELEASE_LOG_RES; 229 /* 230 * The symlink will fit into the inode data fork? 231 * There can't be any attributes so we get the whole variable part. 232 */ 233 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 234 fs_blocks = 0; 235 else 236 fs_blocks = xfs_symlink_blocks(mp, pathlen); 237 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 238 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0); 239 if (error == ENOSPC && fs_blocks == 0) { 240 resblks = 0; 241 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0); 242 } 243 if (error) { 244 cancel_flags = 0; 245 goto error_return; 246 } 247 248 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); 249 unlock_dp_on_error = true; 250 251 /* 252 * Check whether the directory allows new symlinks or not. 253 */ 254 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) { 255 error = XFS_ERROR(EPERM); 256 goto error_return; 257 } 258 259 /* 260 * Reserve disk quota : blocks and inode. 261 */ 262 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, 263 pdqp, resblks, 1, 0); 264 if (error) 265 goto error_return; 266 267 /* 268 * Check for ability to enter directory entry, if no space reserved. 269 */ 270 error = xfs_dir_canenter(tp, dp, link_name, resblks); 271 if (error) 272 goto error_return; 273 /* 274 * Initialize the bmap freelist prior to calling either 275 * bmapi or the directory create code. 276 */ 277 xfs_bmap_init(&free_list, &first_block); 278 279 /* 280 * Allocate an inode for the symlink. 281 */ 282 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 283 prid, resblks > 0, &ip, NULL); 284 if (error) { 285 if (error == ENOSPC) 286 goto error_return; 287 goto error1; 288 } 289 290 /* 291 * An error after we've joined dp to the transaction will result in the 292 * transaction cancel unlocking dp so don't do it explicitly in the 293 * error path. 294 */ 295 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); 296 unlock_dp_on_error = false; 297 298 /* 299 * Also attach the dquot(s) to it, if applicable. 300 */ 301 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 302 303 if (resblks) 304 resblks -= XFS_IALLOC_SPACE_RES(mp); 305 /* 306 * If the symlink will fit into the inode, write it inline. 307 */ 308 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 309 xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK); 310 memcpy(ip->i_df.if_u1.if_data, target_path, pathlen); 311 ip->i_d.di_size = pathlen; 312 313 /* 314 * The inode was initially created in extent format. 315 */ 316 ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT); 317 ip->i_df.if_flags |= XFS_IFINLINE; 318 319 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 320 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 321 322 } else { 323 int offset; 324 325 first_fsb = 0; 326 nmaps = XFS_SYMLINK_MAPS; 327 328 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 329 XFS_BMAPI_METADATA, &first_block, resblks, 330 mval, &nmaps, &free_list); 331 if (error) 332 goto error2; 333 334 if (resblks) 335 resblks -= fs_blocks; 336 ip->i_d.di_size = pathlen; 337 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 338 339 cur_chunk = target_path; 340 offset = 0; 341 for (n = 0; n < nmaps; n++) { 342 char *buf; 343 344 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 345 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 346 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 347 BTOBB(byte_cnt), 0); 348 if (!bp) { 349 error = ENOMEM; 350 goto error2; 351 } 352 bp->b_ops = &xfs_symlink_buf_ops; 353 354 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 355 byte_cnt = min(byte_cnt, pathlen); 356 357 buf = bp->b_addr; 358 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 359 byte_cnt, bp); 360 361 memcpy(buf, cur_chunk, byte_cnt); 362 363 cur_chunk += byte_cnt; 364 pathlen -= byte_cnt; 365 offset += byte_cnt; 366 367 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 368 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 369 (char *)bp->b_addr); 370 } 371 ASSERT(pathlen == 0); 372 } 373 374 /* 375 * Create the directory entry for the symlink. 376 */ 377 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 378 &first_block, &free_list, resblks); 379 if (error) 380 goto error2; 381 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 382 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 383 384 /* 385 * If this is a synchronous mount, make sure that the 386 * symlink transaction goes to disk before returning to 387 * the user. 388 */ 389 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 390 xfs_trans_set_sync(tp); 391 } 392 393 error = xfs_bmap_finish(&tp, &free_list, &committed); 394 if (error) { 395 goto error2; 396 } 397 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 398 xfs_qm_dqrele(udqp); 399 xfs_qm_dqrele(gdqp); 400 xfs_qm_dqrele(pdqp); 401 402 *ipp = ip; 403 return 0; 404 405 error2: 406 IRELE(ip); 407 error1: 408 xfs_bmap_cancel(&free_list); 409 cancel_flags |= XFS_TRANS_ABORT; 410 error_return: 411 xfs_trans_cancel(tp, cancel_flags); 412 xfs_qm_dqrele(udqp); 413 xfs_qm_dqrele(gdqp); 414 xfs_qm_dqrele(pdqp); 415 416 if (unlock_dp_on_error) 417 xfs_iunlock(dp, XFS_ILOCK_EXCL); 418 std_return: 419 return error; 420 } 421 422 /* 423 * Free a symlink that has blocks associated with it. 424 */ 425 STATIC int 426 xfs_inactive_symlink_rmt( 427 struct xfs_inode *ip) 428 { 429 xfs_buf_t *bp; 430 int committed; 431 int done; 432 int error; 433 xfs_fsblock_t first_block; 434 xfs_bmap_free_t free_list; 435 int i; 436 xfs_mount_t *mp; 437 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 438 int nmaps; 439 int size; 440 xfs_trans_t *tp; 441 442 mp = ip->i_mount; 443 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 444 /* 445 * We're freeing a symlink that has some 446 * blocks allocated to it. Free the 447 * blocks here. We know that we've got 448 * either 1 or 2 extents and that we can 449 * free them all in one bunmapi call. 450 */ 451 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 452 453 tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE); 454 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0); 455 if (error) { 456 xfs_trans_cancel(tp, 0); 457 return error; 458 } 459 460 xfs_ilock(ip, XFS_ILOCK_EXCL); 461 xfs_trans_ijoin(tp, ip, 0); 462 463 /* 464 * Lock the inode, fix the size, and join it to the transaction. 465 * Hold it so in the normal path, we still have it locked for 466 * the second transaction. In the error paths we need it 467 * held so the cancel won't rele it, see below. 468 */ 469 size = (int)ip->i_d.di_size; 470 ip->i_d.di_size = 0; 471 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 472 /* 473 * Find the block(s) so we can inval and unmap them. 474 */ 475 done = 0; 476 xfs_bmap_init(&free_list, &first_block); 477 nmaps = ARRAY_SIZE(mval); 478 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 479 mval, &nmaps, 0); 480 if (error) 481 goto error_trans_cancel; 482 /* 483 * Invalidate the block(s). No validation is done. 484 */ 485 for (i = 0; i < nmaps; i++) { 486 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 487 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 488 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 489 if (!bp) { 490 error = ENOMEM; 491 goto error_bmap_cancel; 492 } 493 xfs_trans_binval(tp, bp); 494 } 495 /* 496 * Unmap the dead block(s) to the free_list. 497 */ 498 error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps, 499 &first_block, &free_list, &done); 500 if (error) 501 goto error_bmap_cancel; 502 ASSERT(done); 503 /* 504 * Commit the first transaction. This logs the EFI and the inode. 505 */ 506 error = xfs_bmap_finish(&tp, &free_list, &committed); 507 if (error) 508 goto error_bmap_cancel; 509 /* 510 * The transaction must have been committed, since there were 511 * actually extents freed by xfs_bunmapi. See xfs_bmap_finish. 512 * The new tp has the extent freeing and EFDs. 513 */ 514 ASSERT(committed); 515 /* 516 * The first xact was committed, so add the inode to the new one. 517 * Mark it dirty so it will be logged and moved forward in the log as 518 * part of every commit. 519 */ 520 xfs_trans_ijoin(tp, ip, 0); 521 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 522 /* 523 * Commit the transaction containing extent freeing and EFDs. 524 */ 525 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 526 if (error) { 527 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 528 goto error_unlock; 529 } 530 531 /* 532 * Remove the memory for extent descriptions (just bookkeeping). 533 */ 534 if (ip->i_df.if_bytes) 535 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 536 ASSERT(ip->i_df.if_bytes == 0); 537 538 xfs_iunlock(ip, XFS_ILOCK_EXCL); 539 return 0; 540 541 error_bmap_cancel: 542 xfs_bmap_cancel(&free_list); 543 error_trans_cancel: 544 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT); 545 error_unlock: 546 xfs_iunlock(ip, XFS_ILOCK_EXCL); 547 return error; 548 } 549 550 /* 551 * xfs_inactive_symlink - free a symlink 552 */ 553 int 554 xfs_inactive_symlink( 555 struct xfs_inode *ip) 556 { 557 struct xfs_mount *mp = ip->i_mount; 558 int pathlen; 559 560 trace_xfs_inactive_symlink(ip); 561 562 if (XFS_FORCED_SHUTDOWN(mp)) 563 return XFS_ERROR(EIO); 564 565 xfs_ilock(ip, XFS_ILOCK_EXCL); 566 567 /* 568 * Zero length symlinks _can_ exist. 569 */ 570 pathlen = (int)ip->i_d.di_size; 571 if (!pathlen) { 572 xfs_iunlock(ip, XFS_ILOCK_EXCL); 573 return 0; 574 } 575 576 if (pathlen < 0 || pathlen > MAXPATHLEN) { 577 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 578 __func__, (unsigned long long)ip->i_ino, pathlen); 579 xfs_iunlock(ip, XFS_ILOCK_EXCL); 580 ASSERT(0); 581 return XFS_ERROR(EFSCORRUPTED); 582 } 583 584 if (ip->i_df.if_flags & XFS_IFINLINE) { 585 if (ip->i_df.if_bytes > 0) 586 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 587 XFS_DATA_FORK); 588 xfs_iunlock(ip, XFS_ILOCK_EXCL); 589 ASSERT(ip->i_df.if_bytes == 0); 590 return 0; 591 } 592 593 xfs_iunlock(ip, XFS_ILOCK_EXCL); 594 595 /* remove the remote symlink */ 596 return xfs_inactive_symlink_rmt(ip); 597 } 598