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_dir2.h" |
16 | #include "xfs_inode.h" |
17 | #include "xfs_bmap.h" |
18 | #include "xfs_bmap_btree.h" |
19 | #include "xfs_quota.h" |
20 | #include "xfs_symlink.h" |
21 | #include "xfs_trans_space.h" |
22 | #include "xfs_trace.h" |
23 | #include "xfs_trans.h" |
24 | #include "xfs_ialloc.h" |
25 | #include "xfs_error.h" |
26 | #include "xfs_health.h" |
27 | #include "xfs_symlink_remote.h" |
28 | |
29 | int |
30 | xfs_readlink( |
31 | struct xfs_inode *ip, |
32 | char *link) |
33 | { |
34 | struct xfs_mount *mp = ip->i_mount; |
35 | xfs_fsize_t pathlen; |
36 | int error; |
37 | |
38 | trace_xfs_readlink(ip); |
39 | |
40 | if (xfs_is_shutdown(mp)) |
41 | return -EIO; |
42 | if (xfs_ifork_zapped(ip, XFS_DATA_FORK)) |
43 | return -EIO; |
44 | |
45 | xfs_ilock(ip, XFS_ILOCK_SHARED); |
46 | |
47 | pathlen = ip->i_disk_size; |
48 | if (!pathlen) |
49 | goto out_corrupt; |
50 | |
51 | if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
52 | xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)" , |
53 | __func__, (unsigned long long) ip->i_ino, |
54 | (long long) pathlen); |
55 | ASSERT(0); |
56 | goto out_corrupt; |
57 | } |
58 | |
59 | if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
60 | /* |
61 | * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED |
62 | * if if_data is junk. |
63 | */ |
64 | if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_data)) |
65 | goto out_corrupt; |
66 | |
67 | memcpy(link, ip->i_df.if_data, pathlen + 1); |
68 | error = 0; |
69 | } else { |
70 | error = xfs_symlink_remote_read(ip, link); |
71 | } |
72 | |
73 | xfs_iunlock(ip, XFS_ILOCK_SHARED); |
74 | return error; |
75 | out_corrupt: |
76 | xfs_iunlock(ip, XFS_ILOCK_SHARED); |
77 | xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
78 | return -EFSCORRUPTED; |
79 | } |
80 | |
81 | int |
82 | xfs_symlink( |
83 | struct mnt_idmap *idmap, |
84 | struct xfs_inode *dp, |
85 | struct xfs_name *link_name, |
86 | const char *target_path, |
87 | umode_t mode, |
88 | struct xfs_inode **ipp) |
89 | { |
90 | struct xfs_mount *mp = dp->i_mount; |
91 | struct xfs_trans *tp = NULL; |
92 | struct xfs_inode *ip = NULL; |
93 | int error = 0; |
94 | int pathlen; |
95 | bool unlock_dp_on_error = false; |
96 | xfs_filblks_t fs_blocks; |
97 | prid_t prid; |
98 | struct xfs_dquot *udqp = NULL; |
99 | struct xfs_dquot *gdqp = NULL; |
100 | struct xfs_dquot *pdqp = NULL; |
101 | uint resblks; |
102 | xfs_ino_t ino; |
103 | |
104 | *ipp = NULL; |
105 | |
106 | trace_xfs_symlink(dp, xfs_symlink: link_name); |
107 | |
108 | if (xfs_is_shutdown(mp)) |
109 | return -EIO; |
110 | |
111 | /* |
112 | * Check component lengths of the target path name. |
113 | */ |
114 | pathlen = strlen(target_path); |
115 | if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ |
116 | return -ENAMETOOLONG; |
117 | ASSERT(pathlen > 0); |
118 | |
119 | prid = xfs_get_initial_prid(dp); |
120 | |
121 | /* |
122 | * Make sure that we have allocated dquot(s) on disk. |
123 | */ |
124 | error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(idmap, &init_user_ns), |
125 | mapped_fsgid(idmap, &init_user_ns), prid, |
126 | XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, |
127 | &udqp, &gdqp, &pdqp); |
128 | if (error) |
129 | return error; |
130 | |
131 | /* |
132 | * The symlink will fit into the inode data fork? |
133 | * There can't be any attributes so we get the whole variable part. |
134 | */ |
135 | if (pathlen <= XFS_LITINO(mp)) |
136 | fs_blocks = 0; |
137 | else |
138 | fs_blocks = xfs_symlink_blocks(mp, pathlen); |
139 | resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); |
140 | |
141 | error = xfs_trans_alloc_icreate(mp, resv: &M_RES(mp)->tr_symlink, udqp, gdqp, |
142 | pdqp, dblocks: resblks, tpp: &tp); |
143 | if (error) |
144 | goto out_release_dquots; |
145 | |
146 | xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); |
147 | unlock_dp_on_error = true; |
148 | |
149 | /* |
150 | * Check whether the directory allows new symlinks or not. |
151 | */ |
152 | if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) { |
153 | error = -EPERM; |
154 | goto out_trans_cancel; |
155 | } |
156 | |
157 | /* |
158 | * Allocate an inode for the symlink. |
159 | */ |
160 | error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino); |
161 | if (!error) |
162 | error = xfs_init_new_inode(idmap, tp, dp, ino, |
163 | S_IFLNK | (mode & ~S_IFMT), 1, 0, prid, |
164 | false, &ip); |
165 | if (error) |
166 | goto out_trans_cancel; |
167 | |
168 | /* |
169 | * Now we join the directory inode to the transaction. We do not do it |
170 | * earlier because xfs_dir_ialloc might commit the previous transaction |
171 | * (and release all the locks). An error from here on will result in |
172 | * the transaction cancel unlocking dp so don't do it explicitly in the |
173 | * error path. |
174 | */ |
175 | xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); |
176 | unlock_dp_on_error = false; |
177 | |
178 | /* |
179 | * Also attach the dquot(s) to it, if applicable. |
180 | */ |
181 | xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); |
182 | |
183 | resblks -= XFS_IALLOC_SPACE_RES(mp); |
184 | error = xfs_symlink_write_target(tp, ip, target_path, pathlen, |
185 | fs_blocks, resblks); |
186 | if (error) |
187 | goto out_trans_cancel; |
188 | resblks -= fs_blocks; |
189 | i_size_write(inode: VFS_I(ip), i_size: ip->i_disk_size); |
190 | |
191 | /* |
192 | * Create the directory entry for the symlink. |
193 | */ |
194 | error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks); |
195 | if (error) |
196 | goto out_trans_cancel; |
197 | xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); |
198 | xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); |
199 | xfs_dir_update_hook(dp, ip, delta: 1, name: link_name); |
200 | |
201 | /* |
202 | * If this is a synchronous mount, make sure that the |
203 | * symlink transaction goes to disk before returning to |
204 | * the user. |
205 | */ |
206 | if (xfs_has_wsync(mp) || xfs_has_dirsync(mp)) |
207 | xfs_trans_set_sync(tp); |
208 | |
209 | error = xfs_trans_commit(tp); |
210 | if (error) |
211 | goto out_release_inode; |
212 | |
213 | xfs_qm_dqrele(udqp); |
214 | xfs_qm_dqrele(gdqp); |
215 | xfs_qm_dqrele(pdqp); |
216 | |
217 | *ipp = ip; |
218 | return 0; |
219 | |
220 | out_trans_cancel: |
221 | xfs_trans_cancel(tp); |
222 | out_release_inode: |
223 | /* |
224 | * Wait until after the current transaction is aborted to finish the |
225 | * setup of the inode and release the inode. This prevents recursive |
226 | * transactions and deadlocks from xfs_inactive. |
227 | */ |
228 | if (ip) { |
229 | xfs_finish_inode_setup(ip); |
230 | xfs_irele(ip); |
231 | } |
232 | out_release_dquots: |
233 | xfs_qm_dqrele(udqp); |
234 | xfs_qm_dqrele(gdqp); |
235 | xfs_qm_dqrele(pdqp); |
236 | |
237 | if (unlock_dp_on_error) |
238 | xfs_iunlock(dp, XFS_ILOCK_EXCL); |
239 | return error; |
240 | } |
241 | |
242 | /* |
243 | * Free a symlink that has blocks associated with it. |
244 | * |
245 | * Note: zero length symlinks are not allowed to exist. When we set the size to |
246 | * zero, also change it to a regular file so that it does not get written to |
247 | * disk as a zero length symlink. The inode is on the unlinked list already, so |
248 | * userspace cannot find this inode anymore, so this change is not user visible |
249 | * but allows us to catch corrupt zero-length symlinks in the verifiers. |
250 | */ |
251 | STATIC int |
252 | xfs_inactive_symlink_rmt( |
253 | struct xfs_inode *ip) |
254 | { |
255 | struct xfs_buf *bp; |
256 | int done; |
257 | int error; |
258 | int i; |
259 | xfs_mount_t *mp; |
260 | xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; |
261 | int nmaps; |
262 | int size; |
263 | xfs_trans_t *tp; |
264 | |
265 | mp = ip->i_mount; |
266 | ASSERT(!xfs_need_iread_extents(&ip->i_df)); |
267 | /* |
268 | * We're freeing a symlink that has some |
269 | * blocks allocated to it. Free the |
270 | * blocks here. We know that we've got |
271 | * either 1 or 2 extents and that we can |
272 | * free them all in one bunmapi call. |
273 | */ |
274 | ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2); |
275 | |
276 | error = xfs_trans_alloc(mp, resp: &M_RES(mp)->tr_itruncate, blocks: 0, rtextents: 0, flags: 0, tpp: &tp); |
277 | if (error) |
278 | return error; |
279 | |
280 | xfs_ilock(ip, XFS_ILOCK_EXCL); |
281 | xfs_trans_ijoin(tp, ip, 0); |
282 | |
283 | /* |
284 | * Lock the inode, fix the size, turn it into a regular file and join it |
285 | * to the transaction. Hold it so in the normal path, we still have it |
286 | * locked for the second transaction. In the error paths we need it |
287 | * held so the cancel won't rele it, see below. |
288 | */ |
289 | size = (int)ip->i_disk_size; |
290 | ip->i_disk_size = 0; |
291 | VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG; |
292 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
293 | /* |
294 | * Find the block(s) so we can inval and unmap them. |
295 | */ |
296 | done = 0; |
297 | nmaps = ARRAY_SIZE(mval); |
298 | error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), |
299 | mval, &nmaps, 0); |
300 | if (error) |
301 | goto error_trans_cancel; |
302 | /* |
303 | * Invalidate the block(s). No validation is done. |
304 | */ |
305 | for (i = 0; i < nmaps; i++) { |
306 | error = xfs_trans_get_buf(tp, mp->m_ddev_targp, |
307 | XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), |
308 | XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0, |
309 | &bp); |
310 | if (error) |
311 | goto error_trans_cancel; |
312 | xfs_trans_binval(tp, bp); |
313 | } |
314 | /* |
315 | * Unmap the dead block(s) to the dfops. |
316 | */ |
317 | error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done); |
318 | if (error) |
319 | goto error_trans_cancel; |
320 | ASSERT(done); |
321 | |
322 | /* |
323 | * Commit the transaction. This first logs the EFI and the inode, then |
324 | * rolls and commits the transaction that frees the extents. |
325 | */ |
326 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
327 | error = xfs_trans_commit(tp); |
328 | if (error) { |
329 | ASSERT(xfs_is_shutdown(mp)); |
330 | goto error_unlock; |
331 | } |
332 | |
333 | /* |
334 | * Remove the memory for extent descriptions (just bookkeeping). |
335 | */ |
336 | if (ip->i_df.if_bytes) |
337 | xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); |
338 | ASSERT(ip->i_df.if_bytes == 0); |
339 | |
340 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
341 | return 0; |
342 | |
343 | error_trans_cancel: |
344 | xfs_trans_cancel(tp); |
345 | error_unlock: |
346 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
347 | return error; |
348 | } |
349 | |
350 | /* |
351 | * xfs_inactive_symlink - free a symlink |
352 | */ |
353 | int |
354 | xfs_inactive_symlink( |
355 | struct xfs_inode *ip) |
356 | { |
357 | struct xfs_mount *mp = ip->i_mount; |
358 | int pathlen; |
359 | |
360 | trace_xfs_inactive_symlink(ip); |
361 | |
362 | if (xfs_is_shutdown(mp)) |
363 | return -EIO; |
364 | |
365 | xfs_ilock(ip, XFS_ILOCK_EXCL); |
366 | pathlen = (int)ip->i_disk_size; |
367 | ASSERT(pathlen); |
368 | |
369 | if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
370 | xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)" , |
371 | __func__, (unsigned long long)ip->i_ino, pathlen); |
372 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
373 | ASSERT(0); |
374 | xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
375 | return -EFSCORRUPTED; |
376 | } |
377 | |
378 | /* |
379 | * Inline fork state gets removed by xfs_difree() so we have nothing to |
380 | * do here in that case. |
381 | */ |
382 | if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
383 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
384 | return 0; |
385 | } |
386 | |
387 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
388 | |
389 | /* remove the remote symlink */ |
390 | return xfs_inactive_symlink_rmt(ip); |
391 | } |
392 | |