Line data Source code
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 : #include "xfs_parent.h"
29 : #include "xfs_defer.h"
30 :
31 : /* ----- Kernel only functions below ----- */
32 : int
33 295549515 : xfs_readlink(
34 : struct xfs_inode *ip,
35 : char *link)
36 : {
37 295549515 : struct xfs_mount *mp = ip->i_mount;
38 295549515 : xfs_fsize_t pathlen;
39 295549515 : int error;
40 :
41 295549515 : trace_xfs_readlink(ip);
42 :
43 591109654 : if (xfs_is_shutdown(mp))
44 : return -EIO;
45 :
46 295554798 : xfs_ilock(ip, XFS_ILOCK_SHARED);
47 :
48 295644114 : pathlen = ip->i_disk_size;
49 295644114 : if (!pathlen)
50 0 : goto out_corrupt;
51 :
52 295644114 : if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
53 0 : xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
54 : __func__, (unsigned long long) ip->i_ino,
55 : (long long) pathlen);
56 0 : ASSERT(0);
57 0 : goto out_corrupt;
58 : }
59 :
60 295644114 : if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
61 : /*
62 : * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED
63 : * if if_data is junk.
64 : */
65 55580268 : if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_u1.if_data))
66 0 : goto out_corrupt;
67 :
68 111160536 : memcpy(link, ip->i_df.if_u1.if_data, pathlen + 1);
69 55580268 : error = 0;
70 : } else {
71 240063846 : error = xfs_symlink_remote_read(ip, link);
72 : }
73 :
74 295733136 : xfs_iunlock(ip, XFS_ILOCK_SHARED);
75 295733136 : return error;
76 0 : out_corrupt:
77 0 : xfs_iunlock(ip, XFS_ILOCK_SHARED);
78 0 : xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
79 0 : return -EFSCORRUPTED;
80 : }
81 :
82 : int
83 437723703 : xfs_symlink(
84 : struct mnt_idmap *idmap,
85 : struct xfs_inode *dp,
86 : struct xfs_name *link_name,
87 : const char *target_path,
88 : umode_t mode,
89 : struct xfs_inode **ipp)
90 : {
91 437723703 : struct xfs_mount *mp = dp->i_mount;
92 437723703 : struct xfs_trans *tp = NULL;
93 437723703 : struct xfs_inode *ip = NULL;
94 437723703 : int error = 0;
95 437723703 : int pathlen;
96 437723703 : bool unlock_dp_on_error = false;
97 437723703 : xfs_filblks_t fs_blocks;
98 437723703 : prid_t prid;
99 437723703 : struct xfs_dquot *udqp = NULL;
100 437723703 : struct xfs_dquot *gdqp = NULL;
101 437723703 : struct xfs_dquot *pdqp = NULL;
102 437723703 : uint resblks;
103 437723703 : xfs_ino_t ino;
104 437723703 : struct xfs_parent_defer *parent;
105 :
106 437723703 : *ipp = NULL;
107 :
108 437723703 : trace_xfs_symlink(dp, link_name);
109 :
110 875500212 : if (xfs_is_shutdown(mp))
111 : return -EIO;
112 :
113 : /*
114 : * Check component lengths of the target path name.
115 : */
116 437750105 : pathlen = strlen(target_path);
117 437750105 : if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */
118 : return -ENAMETOOLONG;
119 30973482 : ASSERT(pathlen > 0);
120 :
121 30973482 : prid = xfs_get_initial_prid(dp);
122 :
123 : /*
124 : * Make sure that we have allocated dquot(s) on disk.
125 : */
126 30973482 : error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(idmap, &init_user_ns),
127 : mapped_fsgid(idmap, &init_user_ns), prid,
128 : XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
129 : &udqp, &gdqp, &pdqp);
130 30950871 : if (error)
131 : return error;
132 :
133 : /*
134 : * The symlink will fit into the inode data fork?
135 : * If there are no parent pointers, then there wont't be any attributes.
136 : * So we get the whole variable part, and do not need to reserve extra
137 : * blocks. Otherwise, we need to reserve the blocks.
138 : */
139 30950854 : if (pathlen <= XFS_LITINO(mp) && !xfs_has_parent(mp))
140 : fs_blocks = 0;
141 : else
142 30950719 : fs_blocks = xfs_symlink_blocks(mp, pathlen);
143 30950609 : resblks = xfs_symlink_space_res(mp, link_name->len, fs_blocks);
144 :
145 30949886 : error = xfs_parent_start(mp, &parent);
146 30950298 : if (error)
147 0 : goto out_release_dquots;
148 :
149 30950298 : error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
150 : pdqp, resblks, &tp);
151 30950920 : if (error)
152 13683 : goto out_parent;
153 :
154 30937237 : xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
155 30937206 : unlock_dp_on_error = true;
156 :
157 : /*
158 : * Check whether the directory allows new symlinks or not.
159 : */
160 30937206 : if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {
161 2 : error = -EPERM;
162 2 : goto out_trans_cancel;
163 : }
164 :
165 : /*
166 : * Allocate an inode for the symlink.
167 : */
168 30937204 : error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
169 30937284 : if (!error)
170 30936651 : error = xfs_init_new_inode(idmap, tp, dp, ino,
171 30936651 : S_IFLNK | (mode & ~S_IFMT), 1, 0, prid,
172 : xfs_has_parent(mp), &ip);
173 30936639 : if (error)
174 5 : goto out_trans_cancel;
175 :
176 : /*
177 : * Now we join the directory inode to the transaction. We do not do it
178 : * earlier because xfs_dir_ialloc might commit the previous transaction
179 : * (and release all the locks). An error from here on will result in
180 : * the transaction cancel unlocking dp so don't do it explicitly in the
181 : * error path.
182 : */
183 30936634 : xfs_trans_ijoin(tp, dp, 0);
184 :
185 : /*
186 : * Also attach the dquot(s) to it, if applicable.
187 : */
188 30936273 : xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
189 :
190 30936395 : resblks -= XFS_IALLOC_SPACE_RES(mp);
191 30936395 : error = xfs_symlink_write_target(tp, ip, target_path, pathlen,
192 : fs_blocks, resblks);
193 30933149 : if (error)
194 8 : goto out_trans_cancel;
195 30933141 : resblks -= fs_blocks;
196 30933141 : i_size_write(VFS_I(ip), ip->i_disk_size);
197 :
198 : /*
199 : * Create the directory entry for the symlink.
200 : */
201 30933141 : error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
202 30934582 : if (error)
203 0 : goto out_trans_cancel;
204 30934582 : xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
205 30933446 : xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
206 :
207 30936255 : if (parent) {
208 30935928 : error = xfs_parent_add(tp, parent, dp, link_name, ip);
209 30934591 : if (error)
210 0 : goto out_trans_cancel;
211 : }
212 :
213 30934918 : xfs_dir_update_hook(dp, ip, 1, link_name);
214 :
215 : /*
216 : * If this is a synchronous mount, make sure that the
217 : * symlink transaction goes to disk before returning to
218 : * the user.
219 : */
220 30933302 : if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
221 0 : xfs_trans_set_sync(tp);
222 :
223 30933302 : error = xfs_trans_commit(tp);
224 30936170 : if (error)
225 11 : goto out_release_inode;
226 :
227 30936159 : xfs_qm_dqrele(udqp);
228 30936919 : xfs_qm_dqrele(gdqp);
229 30936516 : xfs_qm_dqrele(pdqp);
230 :
231 30936661 : *ipp = ip;
232 30936661 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
233 30936343 : xfs_iunlock(dp, XFS_ILOCK_EXCL);
234 30936410 : xfs_parent_finish(mp, parent);
235 : return 0;
236 :
237 15 : out_trans_cancel:
238 15 : xfs_trans_cancel(tp);
239 26 : out_release_inode:
240 : /*
241 : * Wait until after the current transaction is aborted to finish the
242 : * setup of the inode and release the inode. This prevents recursive
243 : * transactions and deadlocks from xfs_inactive.
244 : */
245 26 : if (ip) {
246 19 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
247 19 : xfs_finish_inode_setup(ip);
248 19 : xfs_irele(ip);
249 : }
250 7 : out_parent:
251 13709 : xfs_parent_finish(mp, parent);
252 13709 : out_release_dquots:
253 13709 : xfs_qm_dqrele(udqp);
254 13709 : xfs_qm_dqrele(gdqp);
255 13709 : xfs_qm_dqrele(pdqp);
256 :
257 13709 : if (unlock_dp_on_error)
258 26 : xfs_iunlock(dp, XFS_ILOCK_EXCL);
259 : return error;
260 : }
261 :
262 : /*
263 : * Free a symlink that has blocks associated with it.
264 : *
265 : * Note: zero length symlinks are not allowed to exist. When we set the size to
266 : * zero, also change it to a regular file so that it does not get written to
267 : * disk as a zero length symlink. The inode is on the unlinked list already, so
268 : * userspace cannot find this inode anymore, so this change is not user visible
269 : * but allows us to catch corrupt zero-length symlinks in the verifiers.
270 : */
271 : STATIC int
272 24181774 : xfs_inactive_symlink_rmt(
273 : struct xfs_inode *ip)
274 : {
275 24181774 : struct xfs_mount *mp = ip->i_mount;
276 24181774 : struct xfs_trans *tp;
277 24181774 : int error;
278 :
279 24181774 : ASSERT(!xfs_need_iread_extents(&ip->i_df));
280 : /*
281 : * We're freeing a symlink that has some
282 : * blocks allocated to it. Free the
283 : * blocks here. We know that we've got
284 : * either 1 or 2 extents and that we can
285 : * free them all in one bunmapi call.
286 : */
287 24182442 : ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
288 :
289 24182442 : error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
290 24183260 : if (error)
291 : return error;
292 :
293 24183261 : xfs_ilock(ip, XFS_ILOCK_EXCL);
294 24183224 : xfs_trans_ijoin(tp, ip, 0);
295 :
296 : /*
297 : * Lock the inode, fix the size, turn it into a regular file and join it
298 : * to the transaction. Hold it so in the normal path, we still have it
299 : * locked for the second transaction. In the error paths we need it
300 : * held so the cancel won't rele it, see below.
301 : */
302 24181409 : ip->i_disk_size = 0;
303 24181409 : VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
304 24181409 : xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
305 :
306 24183030 : error = xfs_symlink_remote_truncate(tp, ip);
307 24181524 : if (error)
308 0 : goto error_trans_cancel;
309 :
310 24181524 : error = xfs_trans_commit(tp);
311 24183257 : if (error) {
312 14 : ASSERT(xfs_is_shutdown(mp));
313 7 : goto error_unlock;
314 : }
315 :
316 : /*
317 : * Remove the memory for extent descriptions (just bookkeeping).
318 : */
319 24183250 : if (ip->i_df.if_bytes)
320 0 : xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
321 24183250 : ASSERT(ip->i_df.if_bytes == 0);
322 :
323 24183250 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
324 24183250 : return 0;
325 :
326 : error_trans_cancel:
327 0 : xfs_trans_cancel(tp);
328 7 : error_unlock:
329 7 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
330 7 : return error;
331 : }
332 :
333 : /*
334 : * xfs_inactive_symlink - free a symlink
335 : */
336 : int
337 30774760 : xfs_inactive_symlink(
338 : struct xfs_inode *ip)
339 : {
340 30774760 : struct xfs_mount *mp = ip->i_mount;
341 30774760 : int pathlen;
342 :
343 30774760 : trace_xfs_inactive_symlink(ip);
344 :
345 61549440 : if (xfs_is_shutdown(mp))
346 : return -EIO;
347 :
348 30774712 : xfs_ilock(ip, XFS_ILOCK_EXCL);
349 30776086 : pathlen = (int)ip->i_disk_size;
350 30776086 : ASSERT(pathlen);
351 :
352 30776086 : if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
353 0 : xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
354 : __func__, (unsigned long long)ip->i_ino, pathlen);
355 0 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
356 0 : ASSERT(0);
357 0 : xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
358 0 : return -EFSCORRUPTED;
359 : }
360 :
361 : /*
362 : * Inline fork state gets removed by xfs_difree() so we have nothing to
363 : * do here in that case.
364 : */
365 30776086 : if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
366 6594253 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
367 6594253 : return 0;
368 : }
369 :
370 24181833 : xfs_iunlock(ip, XFS_ILOCK_EXCL);
371 :
372 : /* remove the remote symlink */
373 24180750 : return xfs_inactive_symlink_rmt(ip);
374 : }
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