xfs_symlink.c 14 KB

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  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. /* ----- Kernel only functions below ----- */
  44. STATIC int
  45. xfs_readlink_bmap(
  46. struct xfs_inode *ip,
  47. char *link)
  48. {
  49. struct xfs_mount *mp = ip->i_mount;
  50. struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
  51. struct xfs_buf *bp;
  52. xfs_daddr_t d;
  53. char *cur_chunk;
  54. int pathlen = ip->i_d.di_size;
  55. int nmaps = XFS_SYMLINK_MAPS;
  56. int byte_cnt;
  57. int n;
  58. int error = 0;
  59. int fsblocks = 0;
  60. int offset;
  61. fsblocks = xfs_symlink_blocks(mp, pathlen);
  62. error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
  63. if (error)
  64. goto out;
  65. offset = 0;
  66. for (n = 0; n < nmaps; n++) {
  67. d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
  68. byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
  69. bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
  70. &xfs_symlink_buf_ops);
  71. if (!bp)
  72. return -ENOMEM;
  73. error = bp->b_error;
  74. if (error) {
  75. xfs_buf_ioerror_alert(bp, __func__);
  76. xfs_buf_relse(bp);
  77. /* bad CRC means corrupted metadata */
  78. if (error == -EFSBADCRC)
  79. error = -EFSCORRUPTED;
  80. goto out;
  81. }
  82. byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
  83. if (pathlen < byte_cnt)
  84. byte_cnt = pathlen;
  85. cur_chunk = bp->b_addr;
  86. if (xfs_sb_version_hascrc(&mp->m_sb)) {
  87. if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
  88. byte_cnt, bp)) {
  89. error = -EFSCORRUPTED;
  90. xfs_alert(mp,
  91. "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
  92. offset, byte_cnt, ip->i_ino);
  93. xfs_buf_relse(bp);
  94. goto out;
  95. }
  96. cur_chunk += sizeof(struct xfs_dsymlink_hdr);
  97. }
  98. memcpy(link + offset, cur_chunk, byte_cnt);
  99. pathlen -= byte_cnt;
  100. offset += byte_cnt;
  101. xfs_buf_relse(bp);
  102. }
  103. ASSERT(pathlen == 0);
  104. link[ip->i_d.di_size] = '\0';
  105. error = 0;
  106. out:
  107. return error;
  108. }
  109. int
  110. xfs_readlink(
  111. struct xfs_inode *ip,
  112. char *link)
  113. {
  114. struct xfs_mount *mp = ip->i_mount;
  115. xfs_fsize_t pathlen;
  116. int error = 0;
  117. trace_xfs_readlink(ip);
  118. if (XFS_FORCED_SHUTDOWN(mp))
  119. return -EIO;
  120. xfs_ilock(ip, XFS_ILOCK_SHARED);
  121. pathlen = ip->i_d.di_size;
  122. if (!pathlen)
  123. goto out;
  124. if (pathlen < 0 || pathlen > MAXPATHLEN) {
  125. xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
  126. __func__, (unsigned long long) ip->i_ino,
  127. (long long) pathlen);
  128. ASSERT(0);
  129. error = -EFSCORRUPTED;
  130. goto out;
  131. }
  132. if (ip->i_df.if_flags & XFS_IFINLINE) {
  133. memcpy(link, ip->i_df.if_u1.if_data, pathlen);
  134. link[pathlen] = '\0';
  135. } else {
  136. error = xfs_readlink_bmap(ip, link);
  137. }
  138. out:
  139. xfs_iunlock(ip, XFS_ILOCK_SHARED);
  140. return error;
  141. }
  142. int
  143. xfs_symlink(
  144. struct xfs_inode *dp,
  145. struct xfs_name *link_name,
  146. const char *target_path,
  147. umode_t mode,
  148. struct xfs_inode **ipp)
  149. {
  150. struct xfs_mount *mp = dp->i_mount;
  151. struct xfs_trans *tp = NULL;
  152. struct xfs_inode *ip = NULL;
  153. int error = 0;
  154. int pathlen;
  155. struct xfs_bmap_free free_list;
  156. xfs_fsblock_t first_block;
  157. bool unlock_dp_on_error = false;
  158. int committed;
  159. xfs_fileoff_t first_fsb;
  160. xfs_filblks_t fs_blocks;
  161. int nmaps;
  162. struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
  163. xfs_daddr_t d;
  164. const char *cur_chunk;
  165. int byte_cnt;
  166. int n;
  167. xfs_buf_t *bp;
  168. prid_t prid;
  169. struct xfs_dquot *udqp = NULL;
  170. struct xfs_dquot *gdqp = NULL;
  171. struct xfs_dquot *pdqp = NULL;
  172. uint resblks;
  173. *ipp = NULL;
  174. trace_xfs_symlink(dp, link_name);
  175. if (XFS_FORCED_SHUTDOWN(mp))
  176. return -EIO;
  177. /*
  178. * Check component lengths of the target path name.
  179. */
  180. pathlen = strlen(target_path);
  181. if (pathlen >= MAXPATHLEN) /* total string too long */
  182. return -ENAMETOOLONG;
  183. udqp = gdqp = NULL;
  184. prid = xfs_get_initial_prid(dp);
  185. /*
  186. * Make sure that we have allocated dquot(s) on disk.
  187. */
  188. error = xfs_qm_vop_dqalloc(dp,
  189. xfs_kuid_to_uid(current_fsuid()),
  190. xfs_kgid_to_gid(current_fsgid()), prid,
  191. XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
  192. &udqp, &gdqp, &pdqp);
  193. if (error)
  194. return error;
  195. tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
  196. /*
  197. * The symlink will fit into the inode data fork?
  198. * There can't be any attributes so we get the whole variable part.
  199. */
  200. if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
  201. fs_blocks = 0;
  202. else
  203. fs_blocks = xfs_symlink_blocks(mp, pathlen);
  204. resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
  205. error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
  206. if (error == -ENOSPC && fs_blocks == 0) {
  207. resblks = 0;
  208. error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
  209. }
  210. if (error)
  211. goto out_trans_cancel;
  212. xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL |
  213. XFS_IOLOCK_PARENT | XFS_ILOCK_PARENT);
  214. unlock_dp_on_error = true;
  215. /*
  216. * Check whether the directory allows new symlinks or not.
  217. */
  218. if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
  219. error = -EPERM;
  220. goto out_trans_cancel;
  221. }
  222. /*
  223. * Reserve disk quota : blocks and inode.
  224. */
  225. error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
  226. pdqp, resblks, 1, 0);
  227. if (error)
  228. goto out_trans_cancel;
  229. /*
  230. * Check for ability to enter directory entry, if no space reserved.
  231. */
  232. if (!resblks) {
  233. error = xfs_dir_canenter(tp, dp, link_name);
  234. if (error)
  235. goto out_trans_cancel;
  236. }
  237. /*
  238. * Initialize the bmap freelist prior to calling either
  239. * bmapi or the directory create code.
  240. */
  241. xfs_bmap_init(&free_list, &first_block);
  242. /*
  243. * Allocate an inode for the symlink.
  244. */
  245. error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
  246. prid, resblks > 0, &ip, NULL);
  247. if (error)
  248. goto out_trans_cancel;
  249. /*
  250. * Now we join the directory inode to the transaction. We do not do it
  251. * earlier because xfs_dir_ialloc might commit the previous transaction
  252. * (and release all the locks). An error from here on will result in
  253. * the transaction cancel unlocking dp so don't do it explicitly in the
  254. * error path.
  255. */
  256. xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
  257. unlock_dp_on_error = false;
  258. /*
  259. * Also attach the dquot(s) to it, if applicable.
  260. */
  261. xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
  262. if (resblks)
  263. resblks -= XFS_IALLOC_SPACE_RES(mp);
  264. /*
  265. * If the symlink will fit into the inode, write it inline.
  266. */
  267. if (pathlen <= XFS_IFORK_DSIZE(ip)) {
  268. xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
  269. memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
  270. ip->i_d.di_size = pathlen;
  271. /*
  272. * The inode was initially created in extent format.
  273. */
  274. ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
  275. ip->i_df.if_flags |= XFS_IFINLINE;
  276. ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
  277. xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
  278. } else {
  279. int offset;
  280. first_fsb = 0;
  281. nmaps = XFS_SYMLINK_MAPS;
  282. error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
  283. XFS_BMAPI_METADATA, &first_block, resblks,
  284. mval, &nmaps, &free_list);
  285. if (error)
  286. goto out_bmap_cancel;
  287. if (resblks)
  288. resblks -= fs_blocks;
  289. ip->i_d.di_size = pathlen;
  290. xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
  291. cur_chunk = target_path;
  292. offset = 0;
  293. for (n = 0; n < nmaps; n++) {
  294. char *buf;
  295. d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
  296. byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
  297. bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
  298. BTOBB(byte_cnt), 0);
  299. if (!bp) {
  300. error = -ENOMEM;
  301. goto out_bmap_cancel;
  302. }
  303. bp->b_ops = &xfs_symlink_buf_ops;
  304. byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
  305. byte_cnt = min(byte_cnt, pathlen);
  306. buf = bp->b_addr;
  307. buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
  308. byte_cnt, bp);
  309. memcpy(buf, cur_chunk, byte_cnt);
  310. cur_chunk += byte_cnt;
  311. pathlen -= byte_cnt;
  312. offset += byte_cnt;
  313. xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
  314. xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
  315. (char *)bp->b_addr);
  316. }
  317. ASSERT(pathlen == 0);
  318. }
  319. /*
  320. * Create the directory entry for the symlink.
  321. */
  322. error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
  323. &first_block, &free_list, resblks);
  324. if (error)
  325. goto out_bmap_cancel;
  326. xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
  327. xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
  328. /*
  329. * If this is a synchronous mount, make sure that the
  330. * symlink transaction goes to disk before returning to
  331. * the user.
  332. */
  333. if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
  334. xfs_trans_set_sync(tp);
  335. }
  336. error = xfs_bmap_finish(&tp, &free_list, &committed);
  337. if (error)
  338. goto out_bmap_cancel;
  339. error = xfs_trans_commit(tp);
  340. if (error)
  341. goto out_release_inode;
  342. xfs_qm_dqrele(udqp);
  343. xfs_qm_dqrele(gdqp);
  344. xfs_qm_dqrele(pdqp);
  345. *ipp = ip;
  346. return 0;
  347. out_bmap_cancel:
  348. xfs_bmap_cancel(&free_list);
  349. out_trans_cancel:
  350. xfs_trans_cancel(tp);
  351. out_release_inode:
  352. /*
  353. * Wait until after the current transaction is aborted to finish the
  354. * setup of the inode and release the inode. This prevents recursive
  355. * transactions and deadlocks from xfs_inactive.
  356. */
  357. if (ip) {
  358. xfs_finish_inode_setup(ip);
  359. IRELE(ip);
  360. }
  361. xfs_qm_dqrele(udqp);
  362. xfs_qm_dqrele(gdqp);
  363. xfs_qm_dqrele(pdqp);
  364. if (unlock_dp_on_error)
  365. xfs_iunlock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
  366. return error;
  367. }
  368. /*
  369. * Free a symlink that has blocks associated with it.
  370. */
  371. STATIC int
  372. xfs_inactive_symlink_rmt(
  373. struct xfs_inode *ip)
  374. {
  375. xfs_buf_t *bp;
  376. int committed;
  377. int done;
  378. int error;
  379. xfs_fsblock_t first_block;
  380. xfs_bmap_free_t free_list;
  381. int i;
  382. xfs_mount_t *mp;
  383. xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
  384. int nmaps;
  385. int size;
  386. xfs_trans_t *tp;
  387. mp = ip->i_mount;
  388. ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
  389. /*
  390. * We're freeing a symlink that has some
  391. * blocks allocated to it. Free the
  392. * blocks here. We know that we've got
  393. * either 1 or 2 extents and that we can
  394. * free them all in one bunmapi call.
  395. */
  396. ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
  397. tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
  398. error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
  399. if (error) {
  400. xfs_trans_cancel(tp);
  401. return error;
  402. }
  403. xfs_ilock(ip, XFS_ILOCK_EXCL);
  404. xfs_trans_ijoin(tp, ip, 0);
  405. /*
  406. * Lock the inode, fix the size, and join it to the transaction.
  407. * Hold it so in the normal path, we still have it locked for
  408. * the second transaction. In the error paths we need it
  409. * held so the cancel won't rele it, see below.
  410. */
  411. size = (int)ip->i_d.di_size;
  412. ip->i_d.di_size = 0;
  413. xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
  414. /*
  415. * Find the block(s) so we can inval and unmap them.
  416. */
  417. done = 0;
  418. xfs_bmap_init(&free_list, &first_block);
  419. nmaps = ARRAY_SIZE(mval);
  420. error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
  421. mval, &nmaps, 0);
  422. if (error)
  423. goto error_trans_cancel;
  424. /*
  425. * Invalidate the block(s). No validation is done.
  426. */
  427. for (i = 0; i < nmaps; i++) {
  428. bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
  429. XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
  430. XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
  431. if (!bp) {
  432. error = -ENOMEM;
  433. goto error_bmap_cancel;
  434. }
  435. xfs_trans_binval(tp, bp);
  436. }
  437. /*
  438. * Unmap the dead block(s) to the free_list.
  439. */
  440. error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps,
  441. &first_block, &free_list, &done);
  442. if (error)
  443. goto error_bmap_cancel;
  444. ASSERT(done);
  445. /*
  446. * Commit the first transaction. This logs the EFI and the inode.
  447. */
  448. error = xfs_bmap_finish(&tp, &free_list, &committed);
  449. if (error)
  450. goto error_bmap_cancel;
  451. /*
  452. * The transaction must have been committed, since there were
  453. * actually extents freed by xfs_bunmapi. See xfs_bmap_finish.
  454. * The new tp has the extent freeing and EFDs.
  455. */
  456. ASSERT(committed);
  457. /*
  458. * The first xact was committed, so add the inode to the new one.
  459. * Mark it dirty so it will be logged and moved forward in the log as
  460. * part of every commit.
  461. */
  462. xfs_trans_ijoin(tp, ip, 0);
  463. xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
  464. /*
  465. * Commit the transaction containing extent freeing and EFDs.
  466. */
  467. error = xfs_trans_commit(tp);
  468. if (error) {
  469. ASSERT(XFS_FORCED_SHUTDOWN(mp));
  470. goto error_unlock;
  471. }
  472. /*
  473. * Remove the memory for extent descriptions (just bookkeeping).
  474. */
  475. if (ip->i_df.if_bytes)
  476. xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
  477. ASSERT(ip->i_df.if_bytes == 0);
  478. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  479. return 0;
  480. error_bmap_cancel:
  481. xfs_bmap_cancel(&free_list);
  482. error_trans_cancel:
  483. xfs_trans_cancel(tp);
  484. error_unlock:
  485. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  486. return error;
  487. }
  488. /*
  489. * xfs_inactive_symlink - free a symlink
  490. */
  491. int
  492. xfs_inactive_symlink(
  493. struct xfs_inode *ip)
  494. {
  495. struct xfs_mount *mp = ip->i_mount;
  496. int pathlen;
  497. trace_xfs_inactive_symlink(ip);
  498. if (XFS_FORCED_SHUTDOWN(mp))
  499. return -EIO;
  500. xfs_ilock(ip, XFS_ILOCK_EXCL);
  501. /*
  502. * Zero length symlinks _can_ exist.
  503. */
  504. pathlen = (int)ip->i_d.di_size;
  505. if (!pathlen) {
  506. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  507. return 0;
  508. }
  509. if (pathlen < 0 || pathlen > MAXPATHLEN) {
  510. xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
  511. __func__, (unsigned long long)ip->i_ino, pathlen);
  512. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  513. ASSERT(0);
  514. return -EFSCORRUPTED;
  515. }
  516. if (ip->i_df.if_flags & XFS_IFINLINE) {
  517. if (ip->i_df.if_bytes > 0)
  518. xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
  519. XFS_DATA_FORK);
  520. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  521. ASSERT(ip->i_df.if_bytes == 0);
  522. return 0;
  523. }
  524. xfs_iunlock(ip, XFS_ILOCK_EXCL);
  525. /* remove the remote symlink */
  526. return xfs_inactive_symlink_rmt(ip);
  527. }