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