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