1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2022-2024 Oracle.
4 * All rights reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_format.h"
9#include "xfs_da_format.h"
10#include "xfs_log_format.h"
11#include "xfs_shared.h"
12#include "xfs_trans_resv.h"
13#include "xfs_mount.h"
14#include "xfs_bmap_btree.h"
15#include "xfs_inode.h"
16#include "xfs_error.h"
17#include "xfs_trace.h"
18#include "xfs_trans.h"
19#include "xfs_da_btree.h"
20#include "xfs_attr.h"
21#include "xfs_dir2.h"
22#include "xfs_dir2_priv.h"
23#include "xfs_attr_sf.h"
24#include "xfs_bmap.h"
25#include "xfs_defer.h"
26#include "xfs_log.h"
27#include "xfs_xattr.h"
28#include "xfs_parent.h"
29#include "xfs_trans_space.h"
30#include "xfs_attr_item.h"
31#include "xfs_health.h"
32
33struct kmem_cache *xfs_parent_args_cache;
34
35/*
36 * Parent pointer attribute handling.
37 *
38 * Because the attribute name is a filename component, it will never be longer
39 * than 255 bytes and must not contain nulls or slashes. These are roughly the
40 * same constraints that apply to attribute names.
41 *
42 * The attribute value must always be a struct xfs_parent_rec. This means the
43 * attribute will never be in remote format because 12 bytes is nowhere near
44 * xfs_attr_leaf_entsize_local_max() (~75% of block size).
45 *
46 * Creating a new parent attribute will always create a new attribute - there
47 * should never, ever be an existing attribute in the tree for a new inode.
48 * ENOSPC behavior is problematic - creating the inode without the parent
49 * pointer is effectively a corruption, so we allow parent attribute creation
50 * to dip into the reserve block pool to avoid unexpected ENOSPC errors from
51 * occurring.
52 */
53
54/* Return true if parent pointer attr name is valid. */
55bool
56xfs_parent_namecheck(
57 unsigned int attr_flags,
58 const void *name,
59 size_t length)
60{
61 /*
62 * Parent pointers always use logged operations, so there should never
63 * be incomplete xattrs.
64 */
65 if (attr_flags & XFS_ATTR_INCOMPLETE)
66 return false;
67
68 return xfs_dir2_namecheck(name, length);
69}
70
71/* Return true if parent pointer attr value is valid. */
72bool
73xfs_parent_valuecheck(
74 struct xfs_mount *mp,
75 const void *value,
76 size_t valuelen)
77{
78 const struct xfs_parent_rec *rec = value;
79
80 if (!xfs_has_parent(mp))
81 return false;
82
83 /* The xattr value must be a parent record. */
84 if (valuelen != sizeof(struct xfs_parent_rec))
85 return false;
86
87 /* The parent record must be local. */
88 if (value == NULL)
89 return false;
90
91 /* The parent inumber must be valid. */
92 if (!xfs_verify_dir_ino(mp, be64_to_cpu(rec->p_ino)))
93 return false;
94
95 return true;
96}
97
98/* Compute the attribute name hash for a parent pointer. */
99xfs_dahash_t
100xfs_parent_hashval(
101 struct xfs_mount *mp,
102 const uint8_t *name,
103 int namelen,
104 xfs_ino_t parent_ino)
105{
106 struct xfs_name xname = {
107 .name = name,
108 .len = namelen,
109 };
110
111 /*
112 * Use the same dirent name hash as would be used on the directory, but
113 * mix in the parent inode number to avoid collisions on hardlinked
114 * files with identical names but different parents.
115 */
116 return xfs_dir2_hashname(mp, &xname) ^
117 upper_32_bits(parent_ino) ^ lower_32_bits(parent_ino);
118}
119
120/* Compute the attribute name hash from the xattr components. */
121xfs_dahash_t
122xfs_parent_hashattr(
123 struct xfs_mount *mp,
124 const uint8_t *name,
125 int namelen,
126 const void *value,
127 int valuelen)
128{
129 const struct xfs_parent_rec *rec = value;
130
131 /* Requires a local attr value in xfs_parent_rec format */
132 if (valuelen != sizeof(struct xfs_parent_rec)) {
133 ASSERT(valuelen == sizeof(struct xfs_parent_rec));
134 return 0;
135 }
136
137 if (!value) {
138 ASSERT(value != NULL);
139 return 0;
140 }
141
142 return xfs_parent_hashval(mp, name, namelen, be64_to_cpu(rec->p_ino));
143}
144
145/*
146 * Initialize the parent pointer arguments structure. Caller must have zeroed
147 * the contents of @args. @tp is only required for updates.
148 */
149static void
150xfs_parent_da_args_init(
151 struct xfs_da_args *args,
152 struct xfs_trans *tp,
153 struct xfs_parent_rec *rec,
154 struct xfs_inode *child,
155 xfs_ino_t owner,
156 const struct xfs_name *parent_name)
157{
158 args->geo = child->i_mount->m_attr_geo;
159 args->whichfork = XFS_ATTR_FORK;
160 args->attr_filter = XFS_ATTR_PARENT;
161 args->op_flags = XFS_DA_OP_LOGGED | XFS_DA_OP_OKNOENT;
162 args->trans = tp;
163 args->dp = child;
164 args->owner = owner;
165 args->name = parent_name->name;
166 args->namelen = parent_name->len;
167 args->value = rec;
168 args->valuelen = sizeof(struct xfs_parent_rec);
169 xfs_attr_sethash(args);
170}
171
172/* Make sure the incore state is ready for a parent pointer query/update. */
173static inline int
174xfs_parent_iread_extents(
175 struct xfs_trans *tp,
176 struct xfs_inode *child)
177{
178 /* Parent pointers require that the attr fork must exist. */
179 if (XFS_IS_CORRUPT(child->i_mount, !xfs_inode_has_attr_fork(child))) {
180 xfs_inode_mark_sick(ip: child, XFS_SICK_INO_PARENT);
181 return -EFSCORRUPTED;
182 }
183
184 return xfs_iread_extents(tp, child, XFS_ATTR_FORK);
185}
186
187/* Add a parent pointer to reflect a dirent addition. */
188int
189xfs_parent_addname(
190 struct xfs_trans *tp,
191 struct xfs_parent_args *ppargs,
192 struct xfs_inode *dp,
193 const struct xfs_name *parent_name,
194 struct xfs_inode *child)
195{
196 int error;
197
198 error = xfs_parent_iread_extents(tp, child);
199 if (error)
200 return error;
201
202 xfs_inode_to_parent_rec(rec: &ppargs->rec, dp);
203 xfs_parent_da_args_init(&ppargs->args, tp, &ppargs->rec, child,
204 child->i_ino, parent_name);
205 xfs_attr_defer_add(&ppargs->args, XFS_ATTR_DEFER_SET);
206 return 0;
207}
208
209/* Remove a parent pointer to reflect a dirent removal. */
210int
211xfs_parent_removename(
212 struct xfs_trans *tp,
213 struct xfs_parent_args *ppargs,
214 struct xfs_inode *dp,
215 const struct xfs_name *parent_name,
216 struct xfs_inode *child)
217{
218 int error;
219
220 error = xfs_parent_iread_extents(tp, child);
221 if (error)
222 return error;
223
224 xfs_inode_to_parent_rec(rec: &ppargs->rec, dp);
225 xfs_parent_da_args_init(&ppargs->args, tp, &ppargs->rec, child,
226 child->i_ino, parent_name);
227 xfs_attr_defer_add(&ppargs->args, XFS_ATTR_DEFER_REMOVE);
228 return 0;
229}
230
231/* Replace one parent pointer with another to reflect a rename. */
232int
233xfs_parent_replacename(
234 struct xfs_trans *tp,
235 struct xfs_parent_args *ppargs,
236 struct xfs_inode *old_dp,
237 const struct xfs_name *old_name,
238 struct xfs_inode *new_dp,
239 const struct xfs_name *new_name,
240 struct xfs_inode *child)
241{
242 int error;
243
244 error = xfs_parent_iread_extents(tp, child);
245 if (error)
246 return error;
247
248 xfs_inode_to_parent_rec(rec: &ppargs->rec, dp: old_dp);
249 xfs_parent_da_args_init(&ppargs->args, tp, &ppargs->rec, child,
250 child->i_ino, old_name);
251
252 xfs_inode_to_parent_rec(rec: &ppargs->new_rec, dp: new_dp);
253 ppargs->args.new_name = new_name->name;
254 ppargs->args.new_namelen = new_name->len;
255 ppargs->args.new_value = &ppargs->new_rec;
256 ppargs->args.new_valuelen = sizeof(struct xfs_parent_rec);
257 xfs_attr_defer_add(&ppargs->args, XFS_ATTR_DEFER_REPLACE);
258 return 0;
259}
260
261/*
262 * Extract parent pointer information from any parent pointer xattr into
263 * @parent_ino/gen. The last two parameters can be NULL pointers.
264 *
265 * Returns 0 if this is not a parent pointer xattr at all; or -EFSCORRUPTED for
266 * garbage.
267 */
268int
269xfs_parent_from_attr(
270 struct xfs_mount *mp,
271 unsigned int attr_flags,
272 const unsigned char *name,
273 unsigned int namelen,
274 const void *value,
275 unsigned int valuelen,
276 xfs_ino_t *parent_ino,
277 uint32_t *parent_gen)
278{
279 const struct xfs_parent_rec *rec = value;
280
281 ASSERT(attr_flags & XFS_ATTR_PARENT);
282
283 if (!xfs_parent_namecheck(attr_flags, name, namelen))
284 return -EFSCORRUPTED;
285 if (!xfs_parent_valuecheck(mp, value, valuelen))
286 return -EFSCORRUPTED;
287
288 if (parent_ino)
289 *parent_ino = be64_to_cpu(rec->p_ino);
290 if (parent_gen)
291 *parent_gen = be32_to_cpu(rec->p_gen);
292 return 0;
293}
294
295/*
296 * Look up a parent pointer record (@parent_name -> @pptr) of @ip.
297 *
298 * Caller must hold at least ILOCK_SHARED. The scratchpad need not be
299 * initialized.
300 *
301 * Returns 0 if the pointer is found, -ENOATTR if there is no match, or a
302 * negative errno.
303 */
304int
305xfs_parent_lookup(
306 struct xfs_trans *tp,
307 struct xfs_inode *ip,
308 const struct xfs_name *parent_name,
309 struct xfs_parent_rec *pptr,
310 struct xfs_da_args *scratch)
311{
312 memset(scratch, 0, sizeof(struct xfs_da_args));
313 xfs_parent_da_args_init(scratch, tp, pptr, ip, ip->i_ino, parent_name);
314 return xfs_attr_get_ilocked(args: scratch);
315}
316
317/* Sanity-check a parent pointer before we try to perform repairs. */
318static inline bool
319xfs_parent_sanity_check(
320 struct xfs_mount *mp,
321 const struct xfs_name *parent_name,
322 const struct xfs_parent_rec *pptr)
323{
324 if (!xfs_parent_namecheck(XFS_ATTR_PARENT, parent_name->name,
325 parent_name->len))
326 return false;
327
328 if (!xfs_parent_valuecheck(mp, pptr, sizeof(*pptr)))
329 return false;
330
331 return true;
332}
333
334
335/*
336 * Attach the parent pointer (@parent_name -> @pptr) to @ip immediately.
337 * Caller must not have a transaction or hold the ILOCK. This is for
338 * specialized repair functions only. The scratchpad need not be initialized.
339 */
340int
341xfs_parent_set(
342 struct xfs_inode *ip,
343 xfs_ino_t owner,
344 const struct xfs_name *parent_name,
345 struct xfs_parent_rec *pptr,
346 struct xfs_da_args *scratch)
347{
348 if (!xfs_parent_sanity_check(ip->i_mount, parent_name, pptr)) {
349 ASSERT(0);
350 return -EFSCORRUPTED;
351 }
352
353 memset(scratch, 0, sizeof(struct xfs_da_args));
354 xfs_parent_da_args_init(scratch, NULL, pptr, ip, owner, parent_name);
355 return xfs_attr_set(scratch, XFS_ATTRUPDATE_CREATE, false);
356}
357
358/*
359 * Remove the parent pointer (@parent_name -> @pptr) from @ip immediately.
360 * Caller must not have a transaction or hold the ILOCK. This is for
361 * specialized repair functions only. The scratchpad need not be initialized.
362 */
363int
364xfs_parent_unset(
365 struct xfs_inode *ip,
366 xfs_ino_t owner,
367 const struct xfs_name *parent_name,
368 struct xfs_parent_rec *pptr,
369 struct xfs_da_args *scratch)
370{
371 if (!xfs_parent_sanity_check(ip->i_mount, parent_name, pptr)) {
372 ASSERT(0);
373 return -EFSCORRUPTED;
374 }
375
376 memset(scratch, 0, sizeof(struct xfs_da_args));
377 xfs_parent_da_args_init(scratch, NULL, pptr, ip, owner, parent_name);
378 return xfs_attr_set(scratch, XFS_ATTRUPDATE_REMOVE, false);
379}
380

source code of linux/fs/xfs/libxfs/xfs_parent.c