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 ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE)); 135 136 if (XFS_FORCED_SHUTDOWN(mp)) 137 return -EIO; 138 139 xfs_ilock(ip, XFS_ILOCK_SHARED); 140 141 pathlen = ip->i_d.di_size; 142 if (!pathlen) 143 goto out; 144 145 if (pathlen < 0 || pathlen > MAXPATHLEN) { 146 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", 147 __func__, (unsigned long long) ip->i_ino, 148 (long long) pathlen); 149 ASSERT(0); 150 error = -EFSCORRUPTED; 151 goto out; 152 } 153 154 155 error = xfs_readlink_bmap(ip, link); 156 157 out: 158 xfs_iunlock(ip, XFS_ILOCK_SHARED); 159 return error; 160 } 161 162 int 163 xfs_symlink( 164 struct xfs_inode *dp, 165 struct xfs_name *link_name, 166 const char *target_path, 167 umode_t mode, 168 struct xfs_inode **ipp) 169 { 170 struct xfs_mount *mp = dp->i_mount; 171 struct xfs_trans *tp = NULL; 172 struct xfs_inode *ip = NULL; 173 int error = 0; 174 int pathlen; 175 struct xfs_bmap_free free_list; 176 xfs_fsblock_t first_block; 177 bool unlock_dp_on_error = false; 178 xfs_fileoff_t first_fsb; 179 xfs_filblks_t fs_blocks; 180 int nmaps; 181 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 182 xfs_daddr_t d; 183 const char *cur_chunk; 184 int byte_cnt; 185 int n; 186 xfs_buf_t *bp; 187 prid_t prid; 188 struct xfs_dquot *udqp = NULL; 189 struct xfs_dquot *gdqp = NULL; 190 struct xfs_dquot *pdqp = NULL; 191 uint resblks; 192 193 *ipp = NULL; 194 195 trace_xfs_symlink(dp, link_name); 196 197 if (XFS_FORCED_SHUTDOWN(mp)) 198 return -EIO; 199 200 /* 201 * Check component lengths of the target path name. 202 */ 203 pathlen = strlen(target_path); 204 if (pathlen >= MAXPATHLEN) /* total string too long */ 205 return -ENAMETOOLONG; 206 207 udqp = gdqp = NULL; 208 prid = xfs_get_initial_prid(dp); 209 210 /* 211 * Make sure that we have allocated dquot(s) on disk. 212 */ 213 error = xfs_qm_vop_dqalloc(dp, 214 xfs_kuid_to_uid(current_fsuid()), 215 xfs_kgid_to_gid(current_fsgid()), prid, 216 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 217 &udqp, &gdqp, &pdqp); 218 if (error) 219 return error; 220 221 /* 222 * The symlink will fit into the inode data fork? 223 * There can't be any attributes so we get the whole variable part. 224 */ 225 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 226 fs_blocks = 0; 227 else 228 fs_blocks = xfs_symlink_blocks(mp, pathlen); 229 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 230 231 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, resblks, 0, 0, &tp); 232 if (error == -ENOSPC && fs_blocks == 0) { 233 resblks = 0; 234 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, 0, 0, 0, 235 &tp); 236 } 237 if (error) 238 goto out_release_inode; 239 240 xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL | 241 XFS_IOLOCK_PARENT | XFS_ILOCK_PARENT); 242 unlock_dp_on_error = true; 243 244 /* 245 * Check whether the directory allows new symlinks or not. 246 */ 247 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) { 248 error = -EPERM; 249 goto out_trans_cancel; 250 } 251 252 /* 253 * Reserve disk quota : blocks and inode. 254 */ 255 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, 256 pdqp, resblks, 1, 0); 257 if (error) 258 goto out_trans_cancel; 259 260 /* 261 * Check for ability to enter directory entry, if no space reserved. 262 */ 263 if (!resblks) { 264 error = xfs_dir_canenter(tp, dp, link_name); 265 if (error) 266 goto out_trans_cancel; 267 } 268 /* 269 * Initialize the bmap freelist prior to calling either 270 * bmapi or the directory create code. 271 */ 272 xfs_bmap_init(&free_list, &first_block); 273 274 /* 275 * Allocate an inode for the symlink. 276 */ 277 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 278 prid, resblks > 0, &ip, NULL); 279 if (error) 280 goto out_trans_cancel; 281 282 /* 283 * Now we join the directory inode to the transaction. We do not do it 284 * earlier because xfs_dir_ialloc might commit the previous transaction 285 * (and release all the locks). An error from here on will result in 286 * the transaction cancel unlocking dp so don't do it explicitly in the 287 * error path. 288 */ 289 xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL); 290 unlock_dp_on_error = false; 291 292 /* 293 * Also attach the dquot(s) to it, if applicable. 294 */ 295 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 296 297 if (resblks) 298 resblks -= XFS_IALLOC_SPACE_RES(mp); 299 /* 300 * If the symlink will fit into the inode, write it inline. 301 */ 302 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 303 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); 304 305 ip->i_d.di_size = pathlen; 306 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 307 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 308 } else { 309 int offset; 310 311 first_fsb = 0; 312 nmaps = XFS_SYMLINK_MAPS; 313 314 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 315 XFS_BMAPI_METADATA, &first_block, resblks, 316 mval, &nmaps, &free_list); 317 if (error) 318 goto out_bmap_cancel; 319 320 if (resblks) 321 resblks -= fs_blocks; 322 ip->i_d.di_size = pathlen; 323 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 324 325 cur_chunk = target_path; 326 offset = 0; 327 for (n = 0; n < nmaps; n++) { 328 char *buf; 329 330 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 331 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 332 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 333 BTOBB(byte_cnt), 0); 334 if (!bp) { 335 error = -ENOMEM; 336 goto out_bmap_cancel; 337 } 338 bp->b_ops = &xfs_symlink_buf_ops; 339 340 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 341 byte_cnt = min(byte_cnt, pathlen); 342 343 buf = bp->b_addr; 344 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 345 byte_cnt, bp); 346 347 memcpy(buf, cur_chunk, byte_cnt); 348 349 cur_chunk += byte_cnt; 350 pathlen -= byte_cnt; 351 offset += byte_cnt; 352 353 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 354 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 355 (char *)bp->b_addr); 356 } 357 ASSERT(pathlen == 0); 358 } 359 360 /* 361 * Create the directory entry for the symlink. 362 */ 363 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 364 &first_block, &free_list, resblks); 365 if (error) 366 goto out_bmap_cancel; 367 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 368 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 369 370 /* 371 * If this is a synchronous mount, make sure that the 372 * symlink transaction goes to disk before returning to 373 * the user. 374 */ 375 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 376 xfs_trans_set_sync(tp); 377 } 378 379 error = xfs_bmap_finish(&tp, &free_list, NULL); 380 if (error) 381 goto out_bmap_cancel; 382 383 error = xfs_trans_commit(tp); 384 if (error) 385 goto out_release_inode; 386 387 xfs_qm_dqrele(udqp); 388 xfs_qm_dqrele(gdqp); 389 xfs_qm_dqrele(pdqp); 390 391 *ipp = ip; 392 return 0; 393 394 out_bmap_cancel: 395 xfs_bmap_cancel(&free_list); 396 out_trans_cancel: 397 xfs_trans_cancel(tp); 398 out_release_inode: 399 /* 400 * Wait until after the current transaction is aborted to finish the 401 * setup of the inode and release the inode. This prevents recursive 402 * transactions and deadlocks from xfs_inactive. 403 */ 404 if (ip) { 405 xfs_finish_inode_setup(ip); 406 IRELE(ip); 407 } 408 409 xfs_qm_dqrele(udqp); 410 xfs_qm_dqrele(gdqp); 411 xfs_qm_dqrele(pdqp); 412 413 if (unlock_dp_on_error) 414 xfs_iunlock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL); 415 return error; 416 } 417 418 /* 419 * Free a symlink that has blocks associated with it. 420 */ 421 STATIC int 422 xfs_inactive_symlink_rmt( 423 struct xfs_inode *ip) 424 { 425 xfs_buf_t *bp; 426 int done; 427 int error; 428 xfs_fsblock_t first_block; 429 xfs_bmap_free_t free_list; 430 int i; 431 xfs_mount_t *mp; 432 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 433 int nmaps; 434 int size; 435 xfs_trans_t *tp; 436 437 mp = ip->i_mount; 438 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 439 /* 440 * We're freeing a symlink that has some 441 * blocks allocated to it. Free the 442 * blocks here. We know that we've got 443 * either 1 or 2 extents and that we can 444 * free them all in one bunmapi call. 445 */ 446 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 447 448 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); 449 if (error) 450 return error; 451 452 xfs_ilock(ip, XFS_ILOCK_EXCL); 453 xfs_trans_ijoin(tp, ip, 0); 454 455 /* 456 * Lock the inode, fix the size, and join it to the transaction. 457 * Hold it so in the normal path, we still have it locked for 458 * the second transaction. In the error paths we need it 459 * held so the cancel won't rele it, see below. 460 */ 461 size = (int)ip->i_d.di_size; 462 ip->i_d.di_size = 0; 463 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 464 /* 465 * Find the block(s) so we can inval and unmap them. 466 */ 467 done = 0; 468 xfs_bmap_init(&free_list, &first_block); 469 nmaps = ARRAY_SIZE(mval); 470 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 471 mval, &nmaps, 0); 472 if (error) 473 goto error_trans_cancel; 474 /* 475 * Invalidate the block(s). No validation is done. 476 */ 477 for (i = 0; i < nmaps; i++) { 478 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 479 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 480 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 481 if (!bp) { 482 error = -ENOMEM; 483 goto error_bmap_cancel; 484 } 485 xfs_trans_binval(tp, bp); 486 } 487 /* 488 * Unmap the dead block(s) to the free_list. 489 */ 490 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, 491 &first_block, &free_list, &done); 492 if (error) 493 goto error_bmap_cancel; 494 ASSERT(done); 495 /* 496 * Commit the first transaction. This logs the EFI and the inode. 497 */ 498 error = xfs_bmap_finish(&tp, &free_list, ip); 499 if (error) 500 goto error_bmap_cancel; 501 /* 502 * The first xact was committed, so add the inode to the new one. 503 * Mark it dirty so it will be logged and moved forward in the log as 504 * part of every commit. 505 */ 506 xfs_trans_ijoin(tp, ip, 0); 507 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 508 /* 509 * Commit the transaction containing extent freeing and EFDs. 510 */ 511 error = xfs_trans_commit(tp); 512 if (error) { 513 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 514 goto error_unlock; 515 } 516 517 /* 518 * Remove the memory for extent descriptions (just bookkeeping). 519 */ 520 if (ip->i_df.if_bytes) 521 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 522 ASSERT(ip->i_df.if_bytes == 0); 523 524 xfs_iunlock(ip, XFS_ILOCK_EXCL); 525 return 0; 526 527 error_bmap_cancel: 528 xfs_bmap_cancel(&free_list); 529 error_trans_cancel: 530 xfs_trans_cancel(tp); 531 error_unlock: 532 xfs_iunlock(ip, XFS_ILOCK_EXCL); 533 return error; 534 } 535 536 /* 537 * xfs_inactive_symlink - free a symlink 538 */ 539 int 540 xfs_inactive_symlink( 541 struct xfs_inode *ip) 542 { 543 struct xfs_mount *mp = ip->i_mount; 544 int pathlen; 545 546 trace_xfs_inactive_symlink(ip); 547 548 if (XFS_FORCED_SHUTDOWN(mp)) 549 return -EIO; 550 551 xfs_ilock(ip, XFS_ILOCK_EXCL); 552 553 /* 554 * Zero length symlinks _can_ exist. 555 */ 556 pathlen = (int)ip->i_d.di_size; 557 if (!pathlen) { 558 xfs_iunlock(ip, XFS_ILOCK_EXCL); 559 return 0; 560 } 561 562 if (pathlen < 0 || pathlen > MAXPATHLEN) { 563 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 564 __func__, (unsigned long long)ip->i_ino, pathlen); 565 xfs_iunlock(ip, XFS_ILOCK_EXCL); 566 ASSERT(0); 567 return -EFSCORRUPTED; 568 } 569 570 if (ip->i_df.if_flags & XFS_IFINLINE) { 571 if (ip->i_df.if_bytes > 0) 572 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 573 XFS_DATA_FORK); 574 xfs_iunlock(ip, XFS_ILOCK_EXCL); 575 ASSERT(ip->i_df.if_bytes == 0); 576 return 0; 577 } 578 579 xfs_iunlock(ip, XFS_ILOCK_EXCL); 580 581 /* remove the remote symlink */ 582 return xfs_inactive_symlink_rmt(ip); 583 } 584