1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000-2006 Silicon Graphics, Inc. 4 * Copyright (c) 2012-2013 Red Hat, Inc. 5 * All rights reserved. 6 */ 7 #include "xfs.h" 8 #include "xfs_shared.h" 9 #include "xfs_fs.h" 10 #include "xfs_format.h" 11 #include "xfs_log_format.h" 12 #include "xfs_trans_resv.h" 13 #include "xfs_bit.h" 14 #include "xfs_mount.h" 15 #include "xfs_da_format.h" 16 #include "xfs_da_btree.h" 17 #include "xfs_defer.h" 18 #include "xfs_dir2.h" 19 #include "xfs_inode.h" 20 #include "xfs_ialloc.h" 21 #include "xfs_alloc.h" 22 #include "xfs_bmap.h" 23 #include "xfs_bmap_btree.h" 24 #include "xfs_bmap_util.h" 25 #include "xfs_error.h" 26 #include "xfs_quota.h" 27 #include "xfs_trans_space.h" 28 #include "xfs_trace.h" 29 #include "xfs_symlink.h" 30 #include "xfs_trans.h" 31 #include "xfs_log.h" 32 33 /* ----- Kernel only functions below ----- */ 34 int 35 xfs_readlink_bmap_ilocked( 36 struct xfs_inode *ip, 37 char *link) 38 { 39 struct xfs_mount *mp = ip->i_mount; 40 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 41 struct xfs_buf *bp; 42 xfs_daddr_t d; 43 char *cur_chunk; 44 int pathlen = ip->i_d.di_size; 45 int nmaps = XFS_SYMLINK_MAPS; 46 int byte_cnt; 47 int n; 48 int error = 0; 49 int fsblocks = 0; 50 int offset; 51 52 ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); 53 54 fsblocks = xfs_symlink_blocks(mp, pathlen); 55 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); 56 if (error) 57 goto out; 58 59 offset = 0; 60 for (n = 0; n < nmaps; n++) { 61 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 62 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 63 64 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, 65 &xfs_symlink_buf_ops); 66 if (!bp) 67 return -ENOMEM; 68 error = bp->b_error; 69 if (error) { 70 xfs_buf_ioerror_alert(bp, __func__); 71 xfs_buf_relse(bp); 72 73 /* bad CRC means corrupted metadata */ 74 if (error == -EFSBADCRC) 75 error = -EFSCORRUPTED; 76 goto out; 77 } 78 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 79 if (pathlen < byte_cnt) 80 byte_cnt = pathlen; 81 82 cur_chunk = bp->b_addr; 83 if (xfs_sb_version_hascrc(&mp->m_sb)) { 84 if (!xfs_symlink_hdr_ok(ip->i_ino, offset, 85 byte_cnt, bp)) { 86 error = -EFSCORRUPTED; 87 xfs_alert(mp, 88 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)", 89 offset, byte_cnt, ip->i_ino); 90 xfs_buf_relse(bp); 91 goto out; 92 93 } 94 95 cur_chunk += sizeof(struct xfs_dsymlink_hdr); 96 } 97 98 memcpy(link + offset, cur_chunk, byte_cnt); 99 100 pathlen -= byte_cnt; 101 offset += byte_cnt; 102 103 xfs_buf_relse(bp); 104 } 105 ASSERT(pathlen == 0); 106 107 link[ip->i_d.di_size] = '\0'; 108 error = 0; 109 110 out: 111 return error; 112 } 113 114 int 115 xfs_readlink( 116 struct xfs_inode *ip, 117 char *link) 118 { 119 struct xfs_mount *mp = ip->i_mount; 120 xfs_fsize_t pathlen; 121 int error = 0; 122 123 trace_xfs_readlink(ip); 124 125 ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE)); 126 127 if (XFS_FORCED_SHUTDOWN(mp)) 128 return -EIO; 129 130 xfs_ilock(ip, XFS_ILOCK_SHARED); 131 132 pathlen = ip->i_d.di_size; 133 if (!pathlen) 134 goto out; 135 136 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { 137 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", 138 __func__, (unsigned long long) ip->i_ino, 139 (long long) pathlen); 140 ASSERT(0); 141 error = -EFSCORRUPTED; 142 goto out; 143 } 144 145 146 error = xfs_readlink_bmap_ilocked(ip, link); 147 148 out: 149 xfs_iunlock(ip, XFS_ILOCK_SHARED); 150 return error; 151 } 152 153 int 154 xfs_symlink( 155 struct xfs_inode *dp, 156 struct xfs_name *link_name, 157 const char *target_path, 158 umode_t mode, 159 struct xfs_inode **ipp) 160 { 161 struct xfs_mount *mp = dp->i_mount; 162 struct xfs_trans *tp = NULL; 163 struct xfs_inode *ip = NULL; 164 int error = 0; 165 int pathlen; 166 struct xfs_defer_ops dfops; 167 xfs_fsblock_t first_block; 168 bool unlock_dp_on_error = false; 169 xfs_fileoff_t first_fsb; 170 xfs_filblks_t fs_blocks; 171 int nmaps; 172 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 173 xfs_daddr_t d; 174 const char *cur_chunk; 175 int byte_cnt; 176 int n; 177 xfs_buf_t *bp; 178 prid_t prid; 179 struct xfs_dquot *udqp = NULL; 180 struct xfs_dquot *gdqp = NULL; 181 struct xfs_dquot *pdqp = NULL; 182 uint resblks; 183 184 *ipp = NULL; 185 186 trace_xfs_symlink(dp, link_name); 187 188 if (XFS_FORCED_SHUTDOWN(mp)) 189 return -EIO; 190 191 /* 192 * Check component lengths of the target path name. 193 */ 194 pathlen = strlen(target_path); 195 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ 196 return -ENAMETOOLONG; 197 198 udqp = gdqp = NULL; 199 prid = xfs_get_initial_prid(dp); 200 201 /* 202 * Make sure that we have allocated dquot(s) on disk. 203 */ 204 error = xfs_qm_vop_dqalloc(dp, 205 xfs_kuid_to_uid(current_fsuid()), 206 xfs_kgid_to_gid(current_fsgid()), prid, 207 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, 208 &udqp, &gdqp, &pdqp); 209 if (error) 210 return error; 211 212 /* 213 * The symlink will fit into the inode data fork? 214 * There can't be any attributes so we get the whole variable part. 215 */ 216 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version)) 217 fs_blocks = 0; 218 else 219 fs_blocks = xfs_symlink_blocks(mp, pathlen); 220 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); 221 222 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, resblks, 0, 0, &tp); 223 if (error) 224 goto out_release_inode; 225 226 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); 227 unlock_dp_on_error = true; 228 229 /* 230 * Check whether the directory allows new symlinks or not. 231 */ 232 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) { 233 error = -EPERM; 234 goto out_trans_cancel; 235 } 236 237 /* 238 * Reserve disk quota : blocks and inode. 239 */ 240 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, 241 pdqp, resblks, 1, 0); 242 if (error) 243 goto out_trans_cancel; 244 245 /* 246 * Initialize the bmap freelist prior to calling either 247 * bmapi or the directory create code. 248 */ 249 xfs_defer_init(&dfops, &first_block); 250 tp->t_agfl_dfops = &dfops; 251 252 /* 253 * Allocate an inode for the symlink. 254 */ 255 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0, 256 prid, &ip); 257 if (error) 258 goto out_trans_cancel; 259 260 /* 261 * Now we join the directory inode to the transaction. We do not do it 262 * earlier because xfs_dir_ialloc might commit the previous transaction 263 * (and release all the locks). An error from here on will result in 264 * the transaction cancel unlocking dp so don't do it explicitly in the 265 * error path. 266 */ 267 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); 268 unlock_dp_on_error = false; 269 270 /* 271 * Also attach the dquot(s) to it, if applicable. 272 */ 273 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); 274 275 if (resblks) 276 resblks -= XFS_IALLOC_SPACE_RES(mp); 277 /* 278 * If the symlink will fit into the inode, write it inline. 279 */ 280 if (pathlen <= XFS_IFORK_DSIZE(ip)) { 281 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); 282 283 ip->i_d.di_size = pathlen; 284 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL; 285 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 286 } else { 287 int offset; 288 289 first_fsb = 0; 290 nmaps = XFS_SYMLINK_MAPS; 291 292 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, 293 XFS_BMAPI_METADATA, &first_block, resblks, 294 mval, &nmaps, &dfops); 295 if (error) 296 goto out_bmap_cancel; 297 298 if (resblks) 299 resblks -= fs_blocks; 300 ip->i_d.di_size = pathlen; 301 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 302 303 cur_chunk = target_path; 304 offset = 0; 305 for (n = 0; n < nmaps; n++) { 306 char *buf; 307 308 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 309 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 310 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 311 BTOBB(byte_cnt), 0); 312 if (!bp) { 313 error = -ENOMEM; 314 goto out_bmap_cancel; 315 } 316 bp->b_ops = &xfs_symlink_buf_ops; 317 318 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 319 byte_cnt = min(byte_cnt, pathlen); 320 321 buf = bp->b_addr; 322 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, 323 byte_cnt, bp); 324 325 memcpy(buf, cur_chunk, byte_cnt); 326 327 cur_chunk += byte_cnt; 328 pathlen -= byte_cnt; 329 offset += byte_cnt; 330 331 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 332 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 333 (char *)bp->b_addr); 334 } 335 ASSERT(pathlen == 0); 336 } 337 338 /* 339 * Create the directory entry for the symlink. 340 */ 341 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, 342 &first_block, &dfops, resblks); 343 if (error) 344 goto out_bmap_cancel; 345 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 346 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); 347 348 /* 349 * If this is a synchronous mount, make sure that the 350 * symlink transaction goes to disk before returning to 351 * the user. 352 */ 353 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) { 354 xfs_trans_set_sync(tp); 355 } 356 357 error = xfs_defer_finish(&tp, &dfops); 358 if (error) 359 goto out_bmap_cancel; 360 361 error = xfs_trans_commit(tp); 362 if (error) 363 goto out_release_inode; 364 365 xfs_qm_dqrele(udqp); 366 xfs_qm_dqrele(gdqp); 367 xfs_qm_dqrele(pdqp); 368 369 *ipp = ip; 370 return 0; 371 372 out_bmap_cancel: 373 xfs_defer_cancel(&dfops); 374 out_trans_cancel: 375 xfs_trans_cancel(tp); 376 out_release_inode: 377 /* 378 * Wait until after the current transaction is aborted to finish the 379 * setup of the inode and release the inode. This prevents recursive 380 * transactions and deadlocks from xfs_inactive. 381 */ 382 if (ip) { 383 xfs_finish_inode_setup(ip); 384 IRELE(ip); 385 } 386 387 xfs_qm_dqrele(udqp); 388 xfs_qm_dqrele(gdqp); 389 xfs_qm_dqrele(pdqp); 390 391 if (unlock_dp_on_error) 392 xfs_iunlock(dp, XFS_ILOCK_EXCL); 393 return error; 394 } 395 396 /* 397 * Free a symlink that has blocks associated with it. 398 */ 399 STATIC int 400 xfs_inactive_symlink_rmt( 401 struct xfs_inode *ip) 402 { 403 xfs_buf_t *bp; 404 int done; 405 int error; 406 xfs_fsblock_t first_block; 407 struct xfs_defer_ops dfops; 408 int i; 409 xfs_mount_t *mp; 410 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; 411 int nmaps; 412 int size; 413 xfs_trans_t *tp; 414 415 mp = ip->i_mount; 416 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS); 417 /* 418 * We're freeing a symlink that has some 419 * blocks allocated to it. Free the 420 * blocks here. We know that we've got 421 * either 1 or 2 extents and that we can 422 * free them all in one bunmapi call. 423 */ 424 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2); 425 426 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); 427 if (error) 428 return error; 429 430 xfs_ilock(ip, XFS_ILOCK_EXCL); 431 xfs_trans_ijoin(tp, ip, 0); 432 433 /* 434 * Lock the inode, fix the size, and join it to the transaction. 435 * Hold it so in the normal path, we still have it locked for 436 * the second transaction. In the error paths we need it 437 * held so the cancel won't rele it, see below. 438 */ 439 size = (int)ip->i_d.di_size; 440 ip->i_d.di_size = 0; 441 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 442 /* 443 * Find the block(s) so we can inval and unmap them. 444 */ 445 done = 0; 446 xfs_defer_init(&dfops, &first_block); 447 nmaps = ARRAY_SIZE(mval); 448 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), 449 mval, &nmaps, 0); 450 if (error) 451 goto error_trans_cancel; 452 /* 453 * Invalidate the block(s). No validation is done. 454 */ 455 for (i = 0; i < nmaps; i++) { 456 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, 457 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 458 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0); 459 if (!bp) { 460 error = -ENOMEM; 461 goto error_bmap_cancel; 462 } 463 xfs_trans_binval(tp, bp); 464 } 465 /* 466 * Unmap the dead block(s) to the dfops. 467 */ 468 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, 469 &first_block, &dfops, &done); 470 if (error) 471 goto error_bmap_cancel; 472 ASSERT(done); 473 /* 474 * Commit the first transaction. This logs the EFI and the inode. 475 */ 476 xfs_defer_ijoin(&dfops, ip); 477 error = xfs_defer_finish(&tp, &dfops); 478 if (error) 479 goto error_bmap_cancel; 480 481 /* 482 * Commit the transaction containing extent freeing and EFDs. 483 */ 484 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 485 error = xfs_trans_commit(tp); 486 if (error) { 487 ASSERT(XFS_FORCED_SHUTDOWN(mp)); 488 goto error_unlock; 489 } 490 491 /* 492 * Remove the memory for extent descriptions (just bookkeeping). 493 */ 494 if (ip->i_df.if_bytes) 495 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); 496 ASSERT(ip->i_df.if_bytes == 0); 497 498 xfs_iunlock(ip, XFS_ILOCK_EXCL); 499 return 0; 500 501 error_bmap_cancel: 502 xfs_defer_cancel(&dfops); 503 error_trans_cancel: 504 xfs_trans_cancel(tp); 505 error_unlock: 506 xfs_iunlock(ip, XFS_ILOCK_EXCL); 507 return error; 508 } 509 510 /* 511 * xfs_inactive_symlink - free a symlink 512 */ 513 int 514 xfs_inactive_symlink( 515 struct xfs_inode *ip) 516 { 517 struct xfs_mount *mp = ip->i_mount; 518 int pathlen; 519 520 trace_xfs_inactive_symlink(ip); 521 522 if (XFS_FORCED_SHUTDOWN(mp)) 523 return -EIO; 524 525 xfs_ilock(ip, XFS_ILOCK_EXCL); 526 527 /* 528 * Zero length symlinks _can_ exist. 529 */ 530 pathlen = (int)ip->i_d.di_size; 531 if (!pathlen) { 532 xfs_iunlock(ip, XFS_ILOCK_EXCL); 533 return 0; 534 } 535 536 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { 537 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", 538 __func__, (unsigned long long)ip->i_ino, pathlen); 539 xfs_iunlock(ip, XFS_ILOCK_EXCL); 540 ASSERT(0); 541 return -EFSCORRUPTED; 542 } 543 544 if (ip->i_df.if_flags & XFS_IFINLINE) { 545 if (ip->i_df.if_bytes > 0) 546 xfs_idata_realloc(ip, -(ip->i_df.if_bytes), 547 XFS_DATA_FORK); 548 xfs_iunlock(ip, XFS_ILOCK_EXCL); 549 ASSERT(ip->i_df.if_bytes == 0); 550 return 0; 551 } 552 553 xfs_iunlock(ip, XFS_ILOCK_EXCL); 554 555 /* remove the remote symlink */ 556 return xfs_inactive_symlink_rmt(ip); 557 } 558