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 int 47 xfs_readlink_bmap_ilocked( 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 ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); 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 -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, cur_chunk, 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 ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE)); 138 139 if (XFS_FORCED_SHUTDOWN(mp)) 140 return -EIO; 141 142 xfs_ilock(ip, XFS_ILOCK_SHARED); 143 144 pathlen = ip->i_d.di_size; 145 if (!pathlen) 146 goto out; 147 148 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { 149 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", 150 __func__, (unsigned long long) ip->i_ino, 151 (long long) pathlen); 152 ASSERT(0); 153 error = -EFSCORRUPTED; 154 goto out; 155 } 156 157 158 error = xfs_readlink_bmap_ilocked(ip, link); 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_defer_ops dfops; 179 xfs_fsblock_t first_block; 180 bool unlock_dp_on_error = false; 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 -EIO; 202 203 /* 204 * Check component lengths of the target path name. 205 */ 206 pathlen = strlen(target_path); 207 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ 208 return -ENAMETOOLONG; 209 210 udqp = gdqp = NULL; 211 prid = xfs_get_initial_prid(dp); 212 213 /* 214 * Make sure that we have allocated dquot(s) on disk. 215 */ 216 error = xfs_qm_vop_dqalloc(dp, 217 xfs_kuid_to_uid(current_fsuid()), 218 xfs_kgid_to_gid(current_fsgid()), prid, 219 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 220 &udqp, &gdqp, &pdqp); 221 if (error) 222 return error; 223 224 /* 225 * The symlink will fit into the inode data fork? 226 * There can't be any attributes so we get the whole variable part. 227 */ 228 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 229 fs_blocks = 0; 230 else 231 fs_blocks = xfs_symlink_blocks(mp, pathlen); 232 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 233 234 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, resblks, 0, 0, &tp); 235 if (error == -ENOSPC && fs_blocks == 0) { 236 resblks = 0; 237 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, 0, 0, 0, 238 &tp); 239 } 240 if (error) 241 goto out_release_inode; 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_defer_init(&dfops, &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_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); 306 307 ip->i_d.di_size = pathlen; 308 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 309 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 310 } else { 311 int offset; 312 313 first_fsb = 0; 314 nmaps = XFS_SYMLINK_MAPS; 315 316 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 317 XFS_BMAPI_METADATA, &first_block, resblks, 318 mval, &nmaps, &dfops); 319 if (error) 320 goto out_bmap_cancel; 321 322 if (resblks) 323 resblks -= fs_blocks; 324 ip->i_d.di_size = pathlen; 325 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 326 327 cur_chunk = target_path; 328 offset = 0; 329 for (n = 0; n < nmaps; n++) { 330 char *buf; 331 332 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 333 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 334 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 335 BTOBB(byte_cnt), 0); 336 if (!bp) { 337 error = -ENOMEM; 338 goto out_bmap_cancel; 339 } 340 bp->b_ops = &xfs_symlink_buf_ops; 341 342 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 343 byte_cnt = min(byte_cnt, pathlen); 344 345 buf = bp->b_addr; 346 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 347 byte_cnt, bp); 348 349 memcpy(buf, cur_chunk, byte_cnt); 350 351 cur_chunk += byte_cnt; 352 pathlen -= byte_cnt; 353 offset += byte_cnt; 354 355 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 356 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 357 (char *)bp->b_addr); 358 } 359 ASSERT(pathlen == 0); 360 } 361 362 /* 363 * Create the directory entry for the symlink. 364 */ 365 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 366 &first_block, &dfops, resblks); 367 if (error) 368 goto out_bmap_cancel; 369 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 370 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 371 372 /* 373 * If this is a synchronous mount, make sure that the 374 * symlink transaction goes to disk before returning to 375 * the user. 376 */ 377 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 378 xfs_trans_set_sync(tp); 379 } 380 381 error = xfs_defer_finish(&tp, &dfops); 382 if (error) 383 goto out_bmap_cancel; 384 385 error = xfs_trans_commit(tp); 386 if (error) 387 goto out_release_inode; 388 389 xfs_qm_dqrele(udqp); 390 xfs_qm_dqrele(gdqp); 391 xfs_qm_dqrele(pdqp); 392 393 *ipp = ip; 394 return 0; 395 396 out_bmap_cancel: 397 xfs_defer_cancel(&dfops); 398 out_trans_cancel: 399 xfs_trans_cancel(tp); 400 out_release_inode: 401 /* 402 * Wait until after the current transaction is aborted to finish the 403 * setup of the inode and release the inode. This prevents recursive 404 * transactions and deadlocks from xfs_inactive. 405 */ 406 if (ip) { 407 xfs_finish_inode_setup(ip); 408 IRELE(ip); 409 } 410 411 xfs_qm_dqrele(udqp); 412 xfs_qm_dqrele(gdqp); 413 xfs_qm_dqrele(pdqp); 414 415 if (unlock_dp_on_error) 416 xfs_iunlock(dp, XFS_ILOCK_EXCL); 417 return error; 418 } 419 420 /* 421 * Free a symlink that has blocks associated with it. 422 */ 423 STATIC int 424 xfs_inactive_symlink_rmt( 425 struct xfs_inode *ip) 426 { 427 xfs_buf_t *bp; 428 int done; 429 int error; 430 xfs_fsblock_t first_block; 431 struct xfs_defer_ops dfops; 432 int i; 433 xfs_mount_t *mp; 434 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 435 int nmaps; 436 int size; 437 xfs_trans_t *tp; 438 439 mp = ip->i_mount; 440 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 441 /* 442 * We're freeing a symlink that has some 443 * blocks allocated to it. Free the 444 * blocks here. We know that we've got 445 * either 1 or 2 extents and that we can 446 * free them all in one bunmapi call. 447 */ 448 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 449 450 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); 451 if (error) 452 return error; 453 454 xfs_ilock(ip, XFS_ILOCK_EXCL); 455 xfs_trans_ijoin(tp, ip, 0); 456 457 /* 458 * Lock the inode, fix the size, and join it to the transaction. 459 * Hold it so in the normal path, we still have it locked for 460 * the second transaction. In the error paths we need it 461 * held so the cancel won't rele it, see below. 462 */ 463 size = (int)ip->i_d.di_size; 464 ip->i_d.di_size = 0; 465 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 466 /* 467 * Find the block(s) so we can inval and unmap them. 468 */ 469 done = 0; 470 xfs_defer_init(&dfops, &first_block); 471 nmaps = ARRAY_SIZE(mval); 472 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 473 mval, &nmaps, 0); 474 if (error) 475 goto error_trans_cancel; 476 /* 477 * Invalidate the block(s). No validation is done. 478 */ 479 for (i = 0; i < nmaps; i++) { 480 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 481 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 482 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 483 if (!bp) { 484 error = -ENOMEM; 485 goto error_bmap_cancel; 486 } 487 xfs_trans_binval(tp, bp); 488 } 489 /* 490 * Unmap the dead block(s) to the dfops. 491 */ 492 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, 493 &first_block, &dfops, &done); 494 if (error) 495 goto error_bmap_cancel; 496 ASSERT(done); 497 /* 498 * Commit the first transaction. This logs the EFI and the inode. 499 */ 500 xfs_defer_ijoin(&dfops, ip); 501 error = xfs_defer_finish(&tp, &dfops); 502 if (error) 503 goto error_bmap_cancel; 504 /* 505 * The first xact was committed, so add the inode to the new one. 506 * Mark it dirty so it will be logged and moved forward in the log as 507 * part of every commit. 508 */ 509 xfs_trans_ijoin(tp, ip, 0); 510 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 511 /* 512 * Commit the transaction containing extent freeing and EFDs. 513 */ 514 error = xfs_trans_commit(tp); 515 if (error) { 516 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 517 goto error_unlock; 518 } 519 520 /* 521 * Remove the memory for extent descriptions (just bookkeeping). 522 */ 523 if (ip->i_df.if_bytes) 524 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 525 ASSERT(ip->i_df.if_bytes == 0); 526 527 xfs_iunlock(ip, XFS_ILOCK_EXCL); 528 return 0; 529 530 error_bmap_cancel: 531 xfs_defer_cancel(&dfops); 532 error_trans_cancel: 533 xfs_trans_cancel(tp); 534 error_unlock: 535 xfs_iunlock(ip, XFS_ILOCK_EXCL); 536 return error; 537 } 538 539 /* 540 * xfs_inactive_symlink - free a symlink 541 */ 542 int 543 xfs_inactive_symlink( 544 struct xfs_inode *ip) 545 { 546 struct xfs_mount *mp = ip->i_mount; 547 int pathlen; 548 549 trace_xfs_inactive_symlink(ip); 550 551 if (XFS_FORCED_SHUTDOWN(mp)) 552 return -EIO; 553 554 xfs_ilock(ip, XFS_ILOCK_EXCL); 555 556 /* 557 * Zero length symlinks _can_ exist. 558 */ 559 pathlen = (int)ip->i_d.di_size; 560 if (!pathlen) { 561 xfs_iunlock(ip, XFS_ILOCK_EXCL); 562 return 0; 563 } 564 565 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { 566 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 567 __func__, (unsigned long long)ip->i_ino, pathlen); 568 xfs_iunlock(ip, XFS_ILOCK_EXCL); 569 ASSERT(0); 570 return -EFSCORRUPTED; 571 } 572 573 if (ip->i_df.if_flags & XFS_IFINLINE) { 574 if (ip->i_df.if_bytes > 0) 575 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 576 XFS_DATA_FORK); 577 xfs_iunlock(ip, XFS_ILOCK_EXCL); 578 ASSERT(ip->i_df.if_bytes == 0); 579 return 0; 580 } 581 582 xfs_iunlock(ip, XFS_ILOCK_EXCL); 583 584 /* remove the remote symlink */ 585 return xfs_inactive_symlink_rmt(ip); 586 } 587