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