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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 | // SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2000-2006 Silicon Graphics, Inc. * Copyright (c) 2012-2013 Red Hat, Inc. * All rights reserved. */ #include "xfs.h" #include "xfs_shared.h" #include "xfs_fs.h" #include "xfs_format.h" #include "xfs_log_format.h" #include "xfs_trans_resv.h" #include "xfs_bit.h" #include "xfs_mount.h" #include "xfs_dir2.h" #include "xfs_inode.h" #include "xfs_bmap.h" #include "xfs_bmap_btree.h" #include "xfs_quota.h" #include "xfs_symlink.h" #include "xfs_trans_space.h" #include "xfs_trace.h" #include "xfs_trans.h" #include "xfs_ialloc.h" #include "xfs_error.h" /* ----- Kernel only functions below ----- */ int xfs_readlink_bmap_ilocked( struct xfs_inode *ip, char *link) { struct xfs_mount *mp = ip->i_mount; struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; struct xfs_buf *bp; xfs_daddr_t d; char *cur_chunk; int pathlen = ip->i_disk_size; int nmaps = XFS_SYMLINK_MAPS; int byte_cnt; int n; int error = 0; int fsblocks = 0; int offset; ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); fsblocks = xfs_symlink_blocks(mp, pathlen); error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); if (error) goto out; offset = 0; for (n = 0; n < nmaps; n++) { d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, &bp, &xfs_symlink_buf_ops); if (error) return error; byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); if (pathlen < byte_cnt) byte_cnt = pathlen; cur_chunk = bp->b_addr; if (xfs_has_crc(mp)) { if (!xfs_symlink_hdr_ok(ip->i_ino, offset, byte_cnt, bp)) { error = -EFSCORRUPTED; xfs_alert(mp, "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)", offset, byte_cnt, ip->i_ino); xfs_buf_relse(bp); goto out; } cur_chunk += sizeof(struct xfs_dsymlink_hdr); } memcpy(link + offset, cur_chunk, byte_cnt); pathlen -= byte_cnt; offset += byte_cnt; xfs_buf_relse(bp); } ASSERT(pathlen == 0); link[ip->i_disk_size] = '\0'; error = 0; out: return error; } int xfs_readlink( struct xfs_inode *ip, char *link) { struct xfs_mount *mp = ip->i_mount; xfs_fsize_t pathlen; int error = -EFSCORRUPTED; trace_xfs_readlink(ip); if (xfs_is_shutdown(mp)) return -EIO; xfs_ilock(ip, XFS_ILOCK_SHARED); pathlen = ip->i_disk_size; if (!pathlen) goto out; if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", __func__, (unsigned long long) ip->i_ino, (long long) pathlen); ASSERT(0); goto out; } if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { /* * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED * if if_data is junk. */ if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_u1.if_data)) goto out; memcpy(link, ip->i_df.if_u1.if_data, pathlen + 1); error = 0; } else { error = xfs_readlink_bmap_ilocked(ip, link); } out: xfs_iunlock(ip, XFS_ILOCK_SHARED); return error; } int xfs_symlink( struct mnt_idmap *idmap, struct xfs_inode *dp, struct xfs_name *link_name, const char *target_path, umode_t mode, struct xfs_inode **ipp) { struct xfs_mount *mp = dp->i_mount; struct xfs_trans *tp = NULL; struct xfs_inode *ip = NULL; int error = 0; int pathlen; bool unlock_dp_on_error = false; xfs_fileoff_t first_fsb; xfs_filblks_t fs_blocks; int nmaps; struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; xfs_daddr_t d; const char *cur_chunk; int byte_cnt; int n; struct xfs_buf *bp; prid_t prid; struct xfs_dquot *udqp = NULL; struct xfs_dquot *gdqp = NULL; struct xfs_dquot *pdqp = NULL; uint resblks; xfs_ino_t ino; *ipp = NULL; trace_xfs_symlink(dp, link_name); if (xfs_is_shutdown(mp)) return -EIO; /* * Check component lengths of the target path name. */ pathlen = strlen(target_path); if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ return -ENAMETOOLONG; ASSERT(pathlen > 0); prid = xfs_get_initial_prid(dp); /* * Make sure that we have allocated dquot(s) on disk. */ error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(idmap, &init_user_ns), mapped_fsgid(idmap, &init_user_ns), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) return error; /* * The symlink will fit into the inode data fork? * There can't be any attributes so we get the whole variable part. */ if (pathlen <= XFS_LITINO(mp)) fs_blocks = 0; else fs_blocks = xfs_symlink_blocks(mp, pathlen); resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp, pdqp, resblks, &tp); if (error) goto out_release_dquots; xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); unlock_dp_on_error = true; /* * Check whether the directory allows new symlinks or not. */ if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) { error = -EPERM; goto out_trans_cancel; } /* * Allocate an inode for the symlink. */ error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino); if (!error) error = xfs_init_new_inode(idmap, tp, dp, ino, S_IFLNK | (mode & ~S_IFMT), 1, 0, prid, false, &ip); if (error) goto out_trans_cancel; /* * Now we join the directory inode to the transaction. We do not do it * earlier because xfs_dir_ialloc might commit the previous transaction * (and release all the locks). An error from here on will result in * the transaction cancel unlocking dp so don't do it explicitly in the * error path. */ xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); unlock_dp_on_error = false; /* * Also attach the dquot(s) to it, if applicable. */ xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); resblks -= XFS_IALLOC_SPACE_RES(mp); /* * If the symlink will fit into the inode, write it inline. */ if (pathlen <= xfs_inode_data_fork_size(ip)) { xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); ip->i_disk_size = pathlen; ip->i_df.if_format = XFS_DINODE_FMT_LOCAL; xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); } else { int offset; first_fsb = 0; nmaps = XFS_SYMLINK_MAPS; error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, XFS_BMAPI_METADATA, resblks, mval, &nmaps); if (error) goto out_trans_cancel; resblks -= fs_blocks; ip->i_disk_size = pathlen; xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); cur_chunk = target_path; offset = 0; for (n = 0; n < nmaps; n++) { char *buf; d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, &bp); if (error) goto out_trans_cancel; bp->b_ops = &xfs_symlink_buf_ops; byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); byte_cnt = min(byte_cnt, pathlen); buf = bp->b_addr; buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, byte_cnt, bp); memcpy(buf, cur_chunk, byte_cnt); cur_chunk += byte_cnt; pathlen -= byte_cnt; offset += byte_cnt; xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - (char *)bp->b_addr); } ASSERT(pathlen == 0); } i_size_write(VFS_I(ip), ip->i_disk_size); /* * Create the directory entry for the symlink. */ error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks); if (error) goto out_trans_cancel; xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); /* * If this is a synchronous mount, make sure that the * symlink transaction goes to disk before returning to * the user. */ if (xfs_has_wsync(mp) || xfs_has_dirsync(mp)) xfs_trans_set_sync(tp); error = xfs_trans_commit(tp); if (error) goto out_release_inode; xfs_qm_dqrele(udqp); xfs_qm_dqrele(gdqp); xfs_qm_dqrele(pdqp); *ipp = ip; return 0; out_trans_cancel: xfs_trans_cancel(tp); out_release_inode: /* * Wait until after the current transaction is aborted to finish the * setup of the inode and release the inode. This prevents recursive * transactions and deadlocks from xfs_inactive. */ if (ip) { xfs_finish_inode_setup(ip); xfs_irele(ip); } out_release_dquots: xfs_qm_dqrele(udqp); xfs_qm_dqrele(gdqp); xfs_qm_dqrele(pdqp); if (unlock_dp_on_error) xfs_iunlock(dp, XFS_ILOCK_EXCL); return error; } /* * Free a symlink that has blocks associated with it. * * Note: zero length symlinks are not allowed to exist. When we set the size to * zero, also change it to a regular file so that it does not get written to * disk as a zero length symlink. The inode is on the unlinked list already, so * userspace cannot find this inode anymore, so this change is not user visible * but allows us to catch corrupt zero-length symlinks in the verifiers. */ STATIC int xfs_inactive_symlink_rmt( struct xfs_inode *ip) { struct xfs_buf *bp; int done; int error; int i; xfs_mount_t *mp; xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; int nmaps; int size; xfs_trans_t *tp; mp = ip->i_mount; ASSERT(!xfs_need_iread_extents(&ip->i_df)); /* * We're freeing a symlink that has some * blocks allocated to it. Free the * blocks here. We know that we've got * either 1 or 2 extents and that we can * free them all in one bunmapi call. */ ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2); error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); if (error) return error; xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, 0); /* * Lock the inode, fix the size, turn it into a regular file and join it * to the transaction. Hold it so in the normal path, we still have it * locked for the second transaction. In the error paths we need it * held so the cancel won't rele it, see below. */ size = (int)ip->i_disk_size; ip->i_disk_size = 0; VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG; xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); /* * Find the block(s) so we can inval and unmap them. */ done = 0; nmaps = ARRAY_SIZE(mval); error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), mval, &nmaps, 0); if (error) goto error_trans_cancel; /* * Invalidate the block(s). No validation is done. */ for (i = 0; i < nmaps; i++) { error = xfs_trans_get_buf(tp, mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0, &bp); if (error) goto error_trans_cancel; xfs_trans_binval(tp, bp); } /* * Unmap the dead block(s) to the dfops. */ error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done); if (error) goto error_trans_cancel; ASSERT(done); /* * Commit the transaction. This first logs the EFI and the inode, then * rolls and commits the transaction that frees the extents. */ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); error = xfs_trans_commit(tp); if (error) { ASSERT(xfs_is_shutdown(mp)); goto error_unlock; } /* * Remove the memory for extent descriptions (just bookkeeping). */ if (ip->i_df.if_bytes) xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); ASSERT(ip->i_df.if_bytes == 0); xfs_iunlock(ip, XFS_ILOCK_EXCL); return 0; error_trans_cancel: xfs_trans_cancel(tp); error_unlock: xfs_iunlock(ip, XFS_ILOCK_EXCL); return error; } /* * xfs_inactive_symlink - free a symlink */ int xfs_inactive_symlink( struct xfs_inode *ip) { struct xfs_mount *mp = ip->i_mount; int pathlen; trace_xfs_inactive_symlink(ip); if (xfs_is_shutdown(mp)) return -EIO; xfs_ilock(ip, XFS_ILOCK_EXCL); pathlen = (int)ip->i_disk_size; ASSERT(pathlen); if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) { xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", __func__, (unsigned long long)ip->i_ino, pathlen); xfs_iunlock(ip, XFS_ILOCK_EXCL); ASSERT(0); return -EFSCORRUPTED; } /* * Inline fork state gets removed by xfs_difree() so we have nothing to * do here in that case. */ if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { xfs_iunlock(ip, XFS_ILOCK_EXCL); return 0; } xfs_iunlock(ip, XFS_ILOCK_EXCL); /* remove the remote symlink */ return xfs_inactive_symlink_rmt(ip); } |