e1000e: fix PHY init workarounds for i217/i218
[linux-2.6/cjktty.git] / fs / ubifs / xattr.c
blob0f7139bdb2c20370f7f81489b14db155128c2f62
1 /*
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
24 * This file implements UBIFS extended attributes support.
26 * Extended attributes are implemented as regular inodes with attached data,
27 * which limits extended attribute size to UBIFS block size (4KiB). Names of
28 * extended attributes are described by extended attribute entries (xentries),
29 * which are almost identical to directory entries, but have different key type.
31 * In other words, the situation with extended attributes is very similar to
32 * directories. Indeed, any inode (but of course not xattr inodes) may have a
33 * number of associated xentries, just like directory inodes have associated
34 * directory entries. Extended attribute entries store the name of the extended
35 * attribute, the host inode number, and the extended attribute inode number.
36 * Similarly, direntries store the name, the parent and the target inode
37 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
38 * extended attributes.
40 * The number of extended attributes is not limited, but there is Linux
41 * limitation on the maximum possible size of the list of all extended
42 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
43 * the sum of all extended attribute names of the inode does not exceed that
44 * limit.
46 * Extended attributes are synchronous, which means they are written to the
47 * flash media synchronously and there is no write-back for extended attribute
48 * inodes. The extended attribute values are not stored in compressed form on
49 * the media.
51 * Since extended attributes are represented by regular inodes, they are cached
52 * in the VFS inode cache. The xentries are cached in the LNC cache (see
53 * tnc.c).
55 * ACL support is not implemented.
58 #include "ubifs.h"
59 #include <linux/fs.h>
60 #include <linux/slab.h>
61 #include <linux/xattr.h>
62 #include <linux/posix_acl_xattr.h>
65 * Limit the number of extended attributes per inode so that the total size
66 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
68 #define MAX_XATTRS_PER_INODE 65535
71 * Extended attribute type constants.
73 * USER_XATTR: user extended attribute ("user.*")
74 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
75 * SECURITY_XATTR: security extended attribute ("security.*")
77 enum {
78 USER_XATTR,
79 TRUSTED_XATTR,
80 SECURITY_XATTR,
83 static const struct inode_operations empty_iops;
84 static const struct file_operations empty_fops;
86 /**
87 * create_xattr - create an extended attribute.
88 * @c: UBIFS file-system description object
89 * @host: host inode
90 * @nm: extended attribute name
91 * @value: extended attribute value
92 * @size: size of extended attribute value
94 * This is a helper function which creates an extended attribute of name @nm
95 * and value @value for inode @host. The host inode is also updated on flash
96 * because the ctime and extended attribute accounting data changes. This
97 * function returns zero in case of success and a negative error code in case
98 * of failure.
100 static int create_xattr(struct ubifs_info *c, struct inode *host,
101 const struct qstr *nm, const void *value, int size)
103 int err;
104 struct inode *inode;
105 struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
106 struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
107 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
108 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
110 if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE)
111 return -ENOSPC;
113 * Linux limits the maximum size of the extended attribute names list
114 * to %XATTR_LIST_MAX. This means we should not allow creating more
115 * extended attributes if the name list becomes larger. This limitation
116 * is artificial for UBIFS, though.
118 if (host_ui->xattr_names + host_ui->xattr_cnt +
119 nm->len + 1 > XATTR_LIST_MAX)
120 return -ENOSPC;
122 err = ubifs_budget_space(c, &req);
123 if (err)
124 return err;
126 inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
127 if (IS_ERR(inode)) {
128 err = PTR_ERR(inode);
129 goto out_budg;
132 /* Re-define all operations to be "nothing" */
133 inode->i_mapping->a_ops = &empty_aops;
134 inode->i_op = &empty_iops;
135 inode->i_fop = &empty_fops;
137 inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
138 ui = ubifs_inode(inode);
139 ui->xattr = 1;
140 ui->flags |= UBIFS_XATTR_FL;
141 ui->data = kmemdup(value, size, GFP_NOFS);
142 if (!ui->data) {
143 err = -ENOMEM;
144 goto out_free;
146 inode->i_size = ui->ui_size = size;
147 ui->data_len = size;
149 mutex_lock(&host_ui->ui_mutex);
150 host->i_ctime = ubifs_current_time(host);
151 host_ui->xattr_cnt += 1;
152 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
153 host_ui->xattr_size += CALC_XATTR_BYTES(size);
154 host_ui->xattr_names += nm->len;
156 err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
157 if (err)
158 goto out_cancel;
159 mutex_unlock(&host_ui->ui_mutex);
161 ubifs_release_budget(c, &req);
162 insert_inode_hash(inode);
163 iput(inode);
164 return 0;
166 out_cancel:
167 host_ui->xattr_cnt -= 1;
168 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
169 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
170 mutex_unlock(&host_ui->ui_mutex);
171 out_free:
172 make_bad_inode(inode);
173 iput(inode);
174 out_budg:
175 ubifs_release_budget(c, &req);
176 return err;
180 * change_xattr - change an extended attribute.
181 * @c: UBIFS file-system description object
182 * @host: host inode
183 * @inode: extended attribute inode
184 * @value: extended attribute value
185 * @size: size of extended attribute value
187 * This helper function changes the value of extended attribute @inode with new
188 * data from @value. Returns zero in case of success and a negative error code
189 * in case of failure.
191 static int change_xattr(struct ubifs_info *c, struct inode *host,
192 struct inode *inode, const void *value, int size)
194 int err;
195 struct ubifs_inode *host_ui = ubifs_inode(host);
196 struct ubifs_inode *ui = ubifs_inode(inode);
197 struct ubifs_budget_req req = { .dirtied_ino = 2,
198 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
200 ubifs_assert(ui->data_len == inode->i_size);
201 err = ubifs_budget_space(c, &req);
202 if (err)
203 return err;
205 kfree(ui->data);
206 ui->data = kmemdup(value, size, GFP_NOFS);
207 if (!ui->data) {
208 err = -ENOMEM;
209 goto out_free;
211 inode->i_size = ui->ui_size = size;
212 ui->data_len = size;
214 mutex_lock(&host_ui->ui_mutex);
215 host->i_ctime = ubifs_current_time(host);
216 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
217 host_ui->xattr_size += CALC_XATTR_BYTES(size);
220 * It is important to write the host inode after the xattr inode
221 * because if the host inode gets synchronized (via 'fsync()'), then
222 * the extended attribute inode gets synchronized, because it goes
223 * before the host inode in the write-buffer.
225 err = ubifs_jnl_change_xattr(c, inode, host);
226 if (err)
227 goto out_cancel;
228 mutex_unlock(&host_ui->ui_mutex);
230 ubifs_release_budget(c, &req);
231 return 0;
233 out_cancel:
234 host_ui->xattr_size -= CALC_XATTR_BYTES(size);
235 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
236 mutex_unlock(&host_ui->ui_mutex);
237 make_bad_inode(inode);
238 out_free:
239 ubifs_release_budget(c, &req);
240 return err;
244 * check_namespace - check extended attribute name-space.
245 * @nm: extended attribute name
247 * This function makes sure the extended attribute name belongs to one of the
248 * supported extended attribute name-spaces. Returns name-space index in case
249 * of success and a negative error code in case of failure.
251 static int check_namespace(const struct qstr *nm)
253 int type;
255 if (nm->len > UBIFS_MAX_NLEN)
256 return -ENAMETOOLONG;
258 if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
259 XATTR_TRUSTED_PREFIX_LEN)) {
260 if (nm->name[sizeof(XATTR_TRUSTED_PREFIX) - 1] == '\0')
261 return -EINVAL;
262 type = TRUSTED_XATTR;
263 } else if (!strncmp(nm->name, XATTR_USER_PREFIX,
264 XATTR_USER_PREFIX_LEN)) {
265 if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
266 return -EINVAL;
267 type = USER_XATTR;
268 } else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
269 XATTR_SECURITY_PREFIX_LEN)) {
270 if (nm->name[sizeof(XATTR_SECURITY_PREFIX) - 1] == '\0')
271 return -EINVAL;
272 type = SECURITY_XATTR;
273 } else
274 return -EOPNOTSUPP;
276 return type;
279 static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
281 struct inode *inode;
283 inode = ubifs_iget(c->vfs_sb, inum);
284 if (IS_ERR(inode)) {
285 ubifs_err("dead extended attribute entry, error %d",
286 (int)PTR_ERR(inode));
287 return inode;
289 if (ubifs_inode(inode)->xattr)
290 return inode;
291 ubifs_err("corrupt extended attribute entry");
292 iput(inode);
293 return ERR_PTR(-EINVAL);
296 int ubifs_setxattr(struct dentry *dentry, const char *name,
297 const void *value, size_t size, int flags)
299 struct inode *inode, *host = dentry->d_inode;
300 struct ubifs_info *c = host->i_sb->s_fs_info;
301 struct qstr nm = QSTR_INIT(name, strlen(name));
302 struct ubifs_dent_node *xent;
303 union ubifs_key key;
304 int err, type;
306 dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
307 host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
308 ubifs_assert(mutex_is_locked(&host->i_mutex));
310 if (size > UBIFS_MAX_INO_DATA)
311 return -ERANGE;
313 type = check_namespace(&nm);
314 if (type < 0)
315 return type;
317 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
318 if (!xent)
319 return -ENOMEM;
322 * The extended attribute entries are stored in LNC, so multiple
323 * look-ups do not involve reading the flash.
325 xent_key_init(c, &key, host->i_ino, &nm);
326 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
327 if (err) {
328 if (err != -ENOENT)
329 goto out_free;
331 if (flags & XATTR_REPLACE)
332 /* We are asked not to create the xattr */
333 err = -ENODATA;
334 else
335 err = create_xattr(c, host, &nm, value, size);
336 goto out_free;
339 if (flags & XATTR_CREATE) {
340 /* We are asked not to replace the xattr */
341 err = -EEXIST;
342 goto out_free;
345 inode = iget_xattr(c, le64_to_cpu(xent->inum));
346 if (IS_ERR(inode)) {
347 err = PTR_ERR(inode);
348 goto out_free;
351 err = change_xattr(c, host, inode, value, size);
352 iput(inode);
354 out_free:
355 kfree(xent);
356 return err;
359 ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
360 size_t size)
362 struct inode *inode, *host = dentry->d_inode;
363 struct ubifs_info *c = host->i_sb->s_fs_info;
364 struct qstr nm = QSTR_INIT(name, strlen(name));
365 struct ubifs_inode *ui;
366 struct ubifs_dent_node *xent;
367 union ubifs_key key;
368 int err;
370 dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
371 host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
373 err = check_namespace(&nm);
374 if (err < 0)
375 return err;
377 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
378 if (!xent)
379 return -ENOMEM;
381 xent_key_init(c, &key, host->i_ino, &nm);
382 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
383 if (err) {
384 if (err == -ENOENT)
385 err = -ENODATA;
386 goto out_unlock;
389 inode = iget_xattr(c, le64_to_cpu(xent->inum));
390 if (IS_ERR(inode)) {
391 err = PTR_ERR(inode);
392 goto out_unlock;
395 ui = ubifs_inode(inode);
396 ubifs_assert(inode->i_size == ui->data_len);
397 ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
399 if (buf) {
400 /* If @buf is %NULL we are supposed to return the length */
401 if (ui->data_len > size) {
402 ubifs_err("buffer size %zd, xattr len %d",
403 size, ui->data_len);
404 err = -ERANGE;
405 goto out_iput;
408 memcpy(buf, ui->data, ui->data_len);
410 err = ui->data_len;
412 out_iput:
413 iput(inode);
414 out_unlock:
415 kfree(xent);
416 return err;
419 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
421 union ubifs_key key;
422 struct inode *host = dentry->d_inode;
423 struct ubifs_info *c = host->i_sb->s_fs_info;
424 struct ubifs_inode *host_ui = ubifs_inode(host);
425 struct ubifs_dent_node *xent, *pxent = NULL;
426 int err, len, written = 0;
427 struct qstr nm = { .name = NULL };
429 dbg_gen("ino %lu ('%.*s'), buffer size %zd", host->i_ino,
430 dentry->d_name.len, dentry->d_name.name, size);
432 len = host_ui->xattr_names + host_ui->xattr_cnt;
433 if (!buffer)
435 * We should return the minimum buffer size which will fit a
436 * null-terminated list of all the extended attribute names.
438 return len;
440 if (len > size)
441 return -ERANGE;
443 lowest_xent_key(c, &key, host->i_ino);
444 while (1) {
445 int type;
447 xent = ubifs_tnc_next_ent(c, &key, &nm);
448 if (IS_ERR(xent)) {
449 err = PTR_ERR(xent);
450 break;
453 nm.name = xent->name;
454 nm.len = le16_to_cpu(xent->nlen);
456 type = check_namespace(&nm);
457 if (unlikely(type < 0)) {
458 err = type;
459 break;
462 /* Show trusted namespace only for "power" users */
463 if (type != TRUSTED_XATTR || capable(CAP_SYS_ADMIN)) {
464 memcpy(buffer + written, nm.name, nm.len + 1);
465 written += nm.len + 1;
468 kfree(pxent);
469 pxent = xent;
470 key_read(c, &xent->key, &key);
473 kfree(pxent);
474 if (err != -ENOENT) {
475 ubifs_err("cannot find next direntry, error %d", err);
476 return err;
479 ubifs_assert(written <= size);
480 return written;
483 static int remove_xattr(struct ubifs_info *c, struct inode *host,
484 struct inode *inode, const struct qstr *nm)
486 int err;
487 struct ubifs_inode *host_ui = ubifs_inode(host);
488 struct ubifs_inode *ui = ubifs_inode(inode);
489 struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
490 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
492 ubifs_assert(ui->data_len == inode->i_size);
494 err = ubifs_budget_space(c, &req);
495 if (err)
496 return err;
498 mutex_lock(&host_ui->ui_mutex);
499 host->i_ctime = ubifs_current_time(host);
500 host_ui->xattr_cnt -= 1;
501 host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
502 host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
503 host_ui->xattr_names -= nm->len;
505 err = ubifs_jnl_delete_xattr(c, host, inode, nm);
506 if (err)
507 goto out_cancel;
508 mutex_unlock(&host_ui->ui_mutex);
510 ubifs_release_budget(c, &req);
511 return 0;
513 out_cancel:
514 host_ui->xattr_cnt += 1;
515 host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
516 host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
517 mutex_unlock(&host_ui->ui_mutex);
518 ubifs_release_budget(c, &req);
519 make_bad_inode(inode);
520 return err;
523 int ubifs_removexattr(struct dentry *dentry, const char *name)
525 struct inode *inode, *host = dentry->d_inode;
526 struct ubifs_info *c = host->i_sb->s_fs_info;
527 struct qstr nm = QSTR_INIT(name, strlen(name));
528 struct ubifs_dent_node *xent;
529 union ubifs_key key;
530 int err;
532 dbg_gen("xattr '%s', ino %lu ('%.*s')", name,
533 host->i_ino, dentry->d_name.len, dentry->d_name.name);
534 ubifs_assert(mutex_is_locked(&host->i_mutex));
536 err = check_namespace(&nm);
537 if (err < 0)
538 return err;
540 xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
541 if (!xent)
542 return -ENOMEM;
544 xent_key_init(c, &key, host->i_ino, &nm);
545 err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
546 if (err) {
547 if (err == -ENOENT)
548 err = -ENODATA;
549 goto out_free;
552 inode = iget_xattr(c, le64_to_cpu(xent->inum));
553 if (IS_ERR(inode)) {
554 err = PTR_ERR(inode);
555 goto out_free;
558 ubifs_assert(inode->i_nlink == 1);
559 clear_nlink(inode);
560 err = remove_xattr(c, host, inode, &nm);
561 if (err)
562 set_nlink(inode, 1);
564 /* If @i_nlink is 0, 'iput()' will delete the inode */
565 iput(inode);
567 out_free:
568 kfree(xent);
569 return err;