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, cur_chunk, 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 int committed; 182 xfs_fileoff_t first_fsb; 183 xfs_filblks_t fs_blocks; 184 int nmaps; 185 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 186 xfs_daddr_t d; 187 const char *cur_chunk; 188 int byte_cnt; 189 int n; 190 xfs_buf_t *bp; 191 prid_t prid; 192 struct xfs_dquot *udqp = NULL; 193 struct xfs_dquot *gdqp = NULL; 194 struct xfs_dquot *pdqp = NULL; 195 uint resblks; 196 197 *ipp = NULL; 198 199 trace_xfs_symlink(dp, link_name); 200 201 if (XFS_FORCED_SHUTDOWN(mp)) 202 return -EIO; 203 204 /* 205 * Check component lengths of the target path name. 206 */ 207 pathlen = strlen(target_path); 208 if (pathlen >= MAXPATHLEN) /* total string too long */ 209 return -ENAMETOOLONG; 210 211 udqp = gdqp = NULL; 212 prid = xfs_get_initial_prid(dp); 213 214 /* 215 * Make sure that we have allocated dquot(s) on disk. 216 */ 217 error = xfs_qm_vop_dqalloc(dp, 218 xfs_kuid_to_uid(current_fsuid()), 219 xfs_kgid_to_gid(current_fsgid()), prid, 220 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 221 &udqp, &gdqp, &pdqp); 222 if (error) 223 return error; 224 225 tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK); 226 /* 227 * The symlink will fit into the inode data fork? 228 * There can't be any attributes so we get the whole variable part. 229 */ 230 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 231 fs_blocks = 0; 232 else 233 fs_blocks = xfs_symlink_blocks(mp, pathlen); 234 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 235 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0); 236 if (error == -ENOSPC && fs_blocks == 0) { 237 resblks = 0; 238 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0); 239 } 240 if (error) 241 goto out_trans_cancel; 242 243 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); 244 unlock_dp_on_error = true; 245 246 /* 247 * Check whether the directory allows new symlinks or not. 248 */ 249 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) { 250 error = -EPERM; 251 goto out_trans_cancel; 252 } 253 254 /* 255 * Reserve disk quota : blocks and inode. 256 */ 257 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, 258 pdqp, resblks, 1, 0); 259 if (error) 260 goto out_trans_cancel; 261 262 /* 263 * Check for ability to enter directory entry, if no space reserved. 264 */ 265 if (!resblks) { 266 error = xfs_dir_canenter(tp, dp, link_name); 267 if (error) 268 goto out_trans_cancel; 269 } 270 /* 271 * Initialize the bmap freelist prior to calling either 272 * bmapi or the directory create code. 273 */ 274 xfs_bmap_init(&free_list, &first_block); 275 276 /* 277 * Allocate an inode for the symlink. 278 */ 279 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 280 prid, resblks > 0, &ip, NULL); 281 if (error) 282 goto out_trans_cancel; 283 284 /* 285 * Now we join the directory inode to the transaction. We do not do it 286 * earlier because xfs_dir_ialloc might commit the previous transaction 287 * (and release all the locks). An error from here on will result in 288 * the transaction cancel unlocking dp so don't do it explicitly in the 289 * error path. 290 */ 291 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); 292 unlock_dp_on_error = false; 293 294 /* 295 * Also attach the dquot(s) to it, if applicable. 296 */ 297 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 298 299 if (resblks) 300 resblks -= XFS_IALLOC_SPACE_RES(mp); 301 /* 302 * If the symlink will fit into the inode, write it inline. 303 */ 304 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 305 xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK); 306 memcpy(ip->i_df.if_u1.if_data, target_path, pathlen); 307 ip->i_d.di_size = pathlen; 308 309 /* 310 * The inode was initially created in extent format. 311 */ 312 ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT); 313 ip->i_df.if_flags |= XFS_IFINLINE; 314 315 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 316 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 317 318 } else { 319 int offset; 320 321 first_fsb = 0; 322 nmaps = XFS_SYMLINK_MAPS; 323 324 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 325 XFS_BMAPI_METADATA, &first_block, resblks, 326 mval, &nmaps, &free_list); 327 if (error) 328 goto out_bmap_cancel; 329 330 if (resblks) 331 resblks -= fs_blocks; 332 ip->i_d.di_size = pathlen; 333 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 334 335 cur_chunk = target_path; 336 offset = 0; 337 for (n = 0; n < nmaps; n++) { 338 char *buf; 339 340 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 341 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 342 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 343 BTOBB(byte_cnt), 0); 344 if (!bp) { 345 error = -ENOMEM; 346 goto out_bmap_cancel; 347 } 348 bp->b_ops = &xfs_symlink_buf_ops; 349 350 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 351 byte_cnt = min(byte_cnt, pathlen); 352 353 buf = bp->b_addr; 354 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 355 byte_cnt, bp); 356 357 memcpy(buf, cur_chunk, byte_cnt); 358 359 cur_chunk += byte_cnt; 360 pathlen -= byte_cnt; 361 offset += byte_cnt; 362 363 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 364 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 365 (char *)bp->b_addr); 366 } 367 ASSERT(pathlen == 0); 368 } 369 370 /* 371 * Create the directory entry for the symlink. 372 */ 373 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 374 &first_block, &free_list, resblks); 375 if (error) 376 goto out_bmap_cancel; 377 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 378 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 379 380 /* 381 * If this is a synchronous mount, make sure that the 382 * symlink transaction goes to disk before returning to 383 * the user. 384 */ 385 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 386 xfs_trans_set_sync(tp); 387 } 388 389 error = xfs_bmap_finish(&tp, &free_list, &committed); 390 if (error) 391 goto out_bmap_cancel; 392 393 error = xfs_trans_commit(tp); 394 if (error) 395 goto out_release_inode; 396 397 xfs_qm_dqrele(udqp); 398 xfs_qm_dqrele(gdqp); 399 xfs_qm_dqrele(pdqp); 400 401 *ipp = ip; 402 return 0; 403 404 out_bmap_cancel: 405 xfs_bmap_cancel(&free_list); 406 out_trans_cancel: 407 xfs_trans_cancel(tp); 408 out_release_inode: 409 /* 410 * Wait until after the current transaction is aborted to finish the 411 * setup of the inode and release the inode. This prevents recursive 412 * transactions and deadlocks from xfs_inactive. 413 */ 414 if (ip) { 415 xfs_finish_inode_setup(ip); 416 IRELE(ip); 417 } 418 419 xfs_qm_dqrele(udqp); 420 xfs_qm_dqrele(gdqp); 421 xfs_qm_dqrele(pdqp); 422 423 if (unlock_dp_on_error) 424 xfs_iunlock(dp, XFS_ILOCK_EXCL); 425 return error; 426 } 427 428 /* 429 * Free a symlink that has blocks associated with it. 430 */ 431 STATIC int 432 xfs_inactive_symlink_rmt( 433 struct xfs_inode *ip) 434 { 435 xfs_buf_t *bp; 436 int committed; 437 int done; 438 int error; 439 xfs_fsblock_t first_block; 440 xfs_bmap_free_t free_list; 441 int i; 442 xfs_mount_t *mp; 443 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 444 int nmaps; 445 int size; 446 xfs_trans_t *tp; 447 448 mp = ip->i_mount; 449 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 450 /* 451 * We're freeing a symlink that has some 452 * blocks allocated to it. Free the 453 * blocks here. We know that we've got 454 * either 1 or 2 extents and that we can 455 * free them all in one bunmapi call. 456 */ 457 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 458 459 tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE); 460 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0); 461 if (error) { 462 xfs_trans_cancel(tp); 463 return error; 464 } 465 466 xfs_ilock(ip, XFS_ILOCK_EXCL); 467 xfs_trans_ijoin(tp, ip, 0); 468 469 /* 470 * Lock the inode, fix the size, and join it to the transaction. 471 * Hold it so in the normal path, we still have it locked for 472 * the second transaction. In the error paths we need it 473 * held so the cancel won't rele it, see below. 474 */ 475 size = (int)ip->i_d.di_size; 476 ip->i_d.di_size = 0; 477 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 478 /* 479 * Find the block(s) so we can inval and unmap them. 480 */ 481 done = 0; 482 xfs_bmap_init(&free_list, &first_block); 483 nmaps = ARRAY_SIZE(mval); 484 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 485 mval, &nmaps, 0); 486 if (error) 487 goto error_trans_cancel; 488 /* 489 * Invalidate the block(s). No validation is done. 490 */ 491 for (i = 0; i < nmaps; i++) { 492 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 493 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 494 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 495 if (!bp) { 496 error = -ENOMEM; 497 goto error_bmap_cancel; 498 } 499 xfs_trans_binval(tp, bp); 500 } 501 /* 502 * Unmap the dead block(s) to the free_list. 503 */ 504 error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps, 505 &first_block, &free_list, &done); 506 if (error) 507 goto error_bmap_cancel; 508 ASSERT(done); 509 /* 510 * Commit the first transaction. This logs the EFI and the inode. 511 */ 512 error = xfs_bmap_finish(&tp, &free_list, &committed); 513 if (error) 514 goto error_bmap_cancel; 515 /* 516 * The transaction must have been committed, since there were 517 * actually extents freed by xfs_bunmapi. See xfs_bmap_finish. 518 * The new tp has the extent freeing and EFDs. 519 */ 520 ASSERT(committed); 521 /* 522 * The first xact was committed, so add the inode to the new one. 523 * Mark it dirty so it will be logged and moved forward in the log as 524 * part of every commit. 525 */ 526 xfs_trans_ijoin(tp, ip, 0); 527 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 528 /* 529 * Commit the transaction containing extent freeing and EFDs. 530 */ 531 error = xfs_trans_commit(tp); 532 if (error) { 533 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 534 goto error_unlock; 535 } 536 537 /* 538 * Remove the memory for extent descriptions (just bookkeeping). 539 */ 540 if (ip->i_df.if_bytes) 541 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 542 ASSERT(ip->i_df.if_bytes == 0); 543 544 xfs_iunlock(ip, XFS_ILOCK_EXCL); 545 return 0; 546 547 error_bmap_cancel: 548 xfs_bmap_cancel(&free_list); 549 error_trans_cancel: 550 xfs_trans_cancel(tp); 551 error_unlock: 552 xfs_iunlock(ip, XFS_ILOCK_EXCL); 553 return error; 554 } 555 556 /* 557 * xfs_inactive_symlink - free a symlink 558 */ 559 int 560 xfs_inactive_symlink( 561 struct xfs_inode *ip) 562 { 563 struct xfs_mount *mp = ip->i_mount; 564 int pathlen; 565 566 trace_xfs_inactive_symlink(ip); 567 568 if (XFS_FORCED_SHUTDOWN(mp)) 569 return -EIO; 570 571 xfs_ilock(ip, XFS_ILOCK_EXCL); 572 573 /* 574 * Zero length symlinks _can_ exist. 575 */ 576 pathlen = (int)ip->i_d.di_size; 577 if (!pathlen) { 578 xfs_iunlock(ip, XFS_ILOCK_EXCL); 579 return 0; 580 } 581 582 if (pathlen < 0 || pathlen > MAXPATHLEN) { 583 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 584 __func__, (unsigned long long)ip->i_ino, pathlen); 585 xfs_iunlock(ip, XFS_ILOCK_EXCL); 586 ASSERT(0); 587 return -EFSCORRUPTED; 588 } 589 590 if (ip->i_df.if_flags & XFS_IFINLINE) { 591 if (ip->i_df.if_bytes > 0) 592 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 593 XFS_DATA_FORK); 594 xfs_iunlock(ip, XFS_ILOCK_EXCL); 595 ASSERT(ip->i_df.if_bytes == 0); 596 return 0; 597 } 598 599 xfs_iunlock(ip, XFS_ILOCK_EXCL); 600 601 /* remove the remote symlink */ 602 return xfs_inactive_symlink_rmt(ip); 603 } 604