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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/fs/ext2/xattr.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
6 *
7 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 *
13 */
14
15/*
16 * Extended attributes are stored on disk blocks allocated outside of
17 * any inode. The i_file_acl field is then made to point to this allocated
18 * block. If all extended attributes of an inode are identical, these
19 * inodes may share the same extended attribute block. Such situations
20 * are automatically detected by keeping a cache of recent attribute block
21 * numbers and hashes over the block's contents in memory.
22 *
23 *
24 * Extended attribute block layout:
25 *
26 * +------------------+
27 * | header |
28 * | entry 1 | |
29 * | entry 2 | | growing downwards
30 * | entry 3 | v
31 * | four null bytes |
32 * | . . . |
33 * | value 1 | ^
34 * | value 3 | | growing upwards
35 * | value 2 | |
36 * +------------------+
37 *
38 * The block header is followed by multiple entry descriptors. These entry
Lucas De Marchi25985ed2011-03-30 22:57:33 -030039 * descriptors are variable in size, and aligned to EXT2_XATTR_PAD
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 * byte boundaries. The entry descriptors are sorted by attribute name,
41 * so that two extended attribute blocks can be compared efficiently.
42 *
43 * Attribute values are aligned to the end of the block, stored in
44 * no specific order. They are also padded to EXT2_XATTR_PAD byte
45 * boundaries. No additional gaps are left between them.
46 *
47 * Locking strategy
48 * ----------------
49 * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem.
50 * EA blocks are only changed if they are exclusive to an inode, so
51 * holding xattr_sem also means that nothing but the EA block's reference
52 * count will change. Multiple writers to an EA block are synchronized
53 * by the bh lock. No more than a single bh lock is held at any time
54 * to avoid deadlocks.
55 */
56
57#include <linux/buffer_head.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058#include <linux/init.h>
Randy Dunlap7ca6f112020-03-22 19:45:41 -070059#include <linux/printk.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070060#include <linux/slab.h>
Jan Kara7a2508e2016-02-22 22:35:22 -050061#include <linux/mbcache.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062#include <linux/quotaops.h>
63#include <linux/rwsem.h>
Christoph Hellwig431547b2009-11-13 09:52:56 +000064#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065#include "ext2.h"
66#include "xattr.h"
67#include "acl.h"
68
69#define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data))
70#define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr))
71#define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1)
72#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
73
74#ifdef EXT2_XATTR_DEBUG
75# define ea_idebug(inode, f...) do { \
76 printk(KERN_DEBUG "inode %s:%ld: ", \
77 inode->i_sb->s_id, inode->i_ino); \
78 printk(f); \
79 printk("\n"); \
80 } while (0)
81# define ea_bdebug(bh, f...) do { \
Dmitry Monakhova1c6f0572015-04-13 16:31:37 +040082 printk(KERN_DEBUG "block %pg:%lu: ", \
83 bh->b_bdev, (unsigned long) bh->b_blocknr); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 printk(f); \
85 printk("\n"); \
86 } while (0)
87#else
Randy Dunlap7ca6f112020-03-22 19:45:41 -070088# define ea_idebug(inode, f...) no_printk(f)
89# define ea_bdebug(bh, f...) no_printk(f)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090#endif
91
92static int ext2_xattr_set2(struct inode *, struct buffer_head *,
93 struct ext2_xattr_header *);
94
Jan Kara7a2508e2016-02-22 22:35:22 -050095static int ext2_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096static struct buffer_head *ext2_xattr_cache_find(struct inode *,
97 struct ext2_xattr_header *);
98static void ext2_xattr_rehash(struct ext2_xattr_header *,
99 struct ext2_xattr_entry *);
100
Stephen Hemminger749c72ef2010-05-13 17:53:16 -0700101static const struct xattr_handler *ext2_xattr_handler_map[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler,
103#ifdef CONFIG_EXT2_FS_POSIX_ACL
Christoph Hellwig64e178a2013-12-20 05:16:44 -0800104 [EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
105 [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106#endif
107 [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler,
108#ifdef CONFIG_EXT2_FS_SECURITY
109 [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler,
110#endif
111};
112
Stephen Hemminger749c72ef2010-05-13 17:53:16 -0700113const struct xattr_handler *ext2_xattr_handlers[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 &ext2_xattr_user_handler,
115 &ext2_xattr_trusted_handler,
116#ifdef CONFIG_EXT2_FS_POSIX_ACL
Christoph Hellwig64e178a2013-12-20 05:16:44 -0800117 &posix_acl_access_xattr_handler,
118 &posix_acl_default_xattr_handler,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119#endif
120#ifdef CONFIG_EXT2_FS_SECURITY
121 &ext2_xattr_security_handler,
122#endif
123 NULL
124};
125
Tahsin Erdogan47387402017-06-22 11:28:55 -0400126#define EA_BLOCK_CACHE(inode) (EXT2_SB(inode->i_sb)->s_ea_block_cache)
127
Stephen Hemminger749c72ef2010-05-13 17:53:16 -0700128static inline const struct xattr_handler *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129ext2_xattr_handler(int name_index)
130{
Stephen Hemminger749c72ef2010-05-13 17:53:16 -0700131 const struct xattr_handler *handler = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
133 if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map))
134 handler = ext2_xattr_handler_map[name_index];
135 return handler;
136}
137
138/*
139 * ext2_xattr_get()
140 *
141 * Copy an extended attribute into the buffer
142 * provided, or compute the buffer size required.
143 * Buffer is NULL to compute the size of the buffer required.
144 *
145 * Returns a negative error number on failure, or the number of bytes
146 * used / required on success.
147 */
148int
149ext2_xattr_get(struct inode *inode, int name_index, const char *name,
150 void *buffer, size_t buffer_size)
151{
152 struct buffer_head *bh = NULL;
153 struct ext2_xattr_entry *entry;
154 size_t name_len, size;
155 char *end;
156 int error;
Tahsin Erdogan47387402017-06-22 11:28:55 -0400157 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
159 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
160 name_index, name, buffer, (long)buffer_size);
161
162 if (name == NULL)
163 return -EINVAL;
Wang Sheng-Hui03b5bb32011-07-22 08:50:13 -0500164 name_len = strlen(name);
165 if (name_len > 255)
166 return -ERANGE;
167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 down_read(&EXT2_I(inode)->xattr_sem);
169 error = -ENODATA;
170 if (!EXT2_I(inode)->i_file_acl)
171 goto cleanup;
172 ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
173 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
174 error = -EIO;
175 if (!bh)
176 goto cleanup;
177 ea_bdebug(bh, "b_count=%d, refcount=%d",
178 atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
179 end = bh->b_data + bh->b_size;
180 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
181 HDR(bh)->h_blocks != cpu_to_le32(1)) {
182bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
183 "inode %ld: bad block %d", inode->i_ino,
184 EXT2_I(inode)->i_file_acl);
185 error = -EIO;
186 goto cleanup;
187 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Wang Sheng-Hui03b5bb32011-07-22 08:50:13 -0500189 /* find named attribute */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 entry = FIRST_ENTRY(bh);
191 while (!IS_LAST_ENTRY(entry)) {
192 struct ext2_xattr_entry *next =
193 EXT2_XATTR_NEXT(entry);
194 if ((char *)next >= end)
195 goto bad_block;
196 if (name_index == entry->e_name_index &&
197 name_len == entry->e_name_len &&
198 memcmp(name, entry->e_name, name_len) == 0)
199 goto found;
200 entry = next;
201 }
Tahsin Erdogan47387402017-06-22 11:28:55 -0400202 if (ext2_xattr_cache_insert(ea_block_cache, bh))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 ea_idebug(inode, "cache insert failed");
204 error = -ENODATA;
205 goto cleanup;
206found:
207 /* check the buffer size */
208 if (entry->e_value_block != 0)
209 goto bad_block;
210 size = le32_to_cpu(entry->e_value_size);
211 if (size > inode->i_sb->s_blocksize ||
212 le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
213 goto bad_block;
214
Tahsin Erdogan47387402017-06-22 11:28:55 -0400215 if (ext2_xattr_cache_insert(ea_block_cache, bh))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 ea_idebug(inode, "cache insert failed");
217 if (buffer) {
218 error = -ERANGE;
219 if (size > buffer_size)
220 goto cleanup;
221 /* return value of attribute */
222 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
223 size);
224 }
225 error = size;
226
227cleanup:
228 brelse(bh);
229 up_read(&EXT2_I(inode)->xattr_sem);
230
231 return error;
232}
233
234/*
235 * ext2_xattr_list()
236 *
237 * Copy a list of attribute names into the buffer
238 * provided, or compute the buffer size required.
239 * Buffer is NULL to compute the size of the buffer required.
240 *
241 * Returns a negative error number on failure, or the number of bytes
242 * used / required on success.
243 */
244static int
Christoph Hellwig431547b2009-11-13 09:52:56 +0000245ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246{
David Howells2b0143b2015-03-17 22:25:59 +0000247 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 struct buffer_head *bh = NULL;
249 struct ext2_xattr_entry *entry;
250 char *end;
251 size_t rest = buffer_size;
252 int error;
Tahsin Erdogan47387402017-06-22 11:28:55 -0400253 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
256 buffer, (long)buffer_size);
257
258 down_read(&EXT2_I(inode)->xattr_sem);
259 error = 0;
260 if (!EXT2_I(inode)->i_file_acl)
261 goto cleanup;
262 ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
263 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
264 error = -EIO;
265 if (!bh)
266 goto cleanup;
267 ea_bdebug(bh, "b_count=%d, refcount=%d",
268 atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
269 end = bh->b_data + bh->b_size;
270 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
271 HDR(bh)->h_blocks != cpu_to_le32(1)) {
272bad_block: ext2_error(inode->i_sb, "ext2_xattr_list",
273 "inode %ld: bad block %d", inode->i_ino,
274 EXT2_I(inode)->i_file_acl);
275 error = -EIO;
276 goto cleanup;
277 }
278
279 /* check the on-disk data structure */
280 entry = FIRST_ENTRY(bh);
281 while (!IS_LAST_ENTRY(entry)) {
282 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry);
283
284 if ((char *)next >= end)
285 goto bad_block;
286 entry = next;
287 }
Tahsin Erdogan47387402017-06-22 11:28:55 -0400288 if (ext2_xattr_cache_insert(ea_block_cache, bh))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 ea_idebug(inode, "cache insert failed");
290
291 /* list the attribute names */
292 for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry);
293 entry = EXT2_XATTR_NEXT(entry)) {
Stephen Hemminger749c72ef2010-05-13 17:53:16 -0700294 const struct xattr_handler *handler =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 ext2_xattr_handler(entry->e_name_index);
296
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100297 if (handler && (!handler->list || handler->list(dentry))) {
298 const char *prefix = handler->prefix ?: handler->name;
299 size_t prefix_len = strlen(prefix);
300 size_t size = prefix_len + entry->e_name_len + 1;
301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 if (buffer) {
303 if (size > rest) {
304 error = -ERANGE;
305 goto cleanup;
306 }
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100307 memcpy(buffer, prefix, prefix_len);
308 buffer += prefix_len;
309 memcpy(buffer, entry->e_name, entry->e_name_len);
310 buffer += entry->e_name_len;
311 *buffer++ = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 }
313 rest -= size;
314 }
315 }
316 error = buffer_size - rest; /* total size */
317
318cleanup:
319 brelse(bh);
320 up_read(&EXT2_I(inode)->xattr_sem);
321
322 return error;
323}
324
325/*
326 * Inode operation listxattr()
327 *
David Howells2b0143b2015-03-17 22:25:59 +0000328 * d_inode(dentry)->i_mutex: don't care
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 */
330ssize_t
331ext2_listxattr(struct dentry *dentry, char *buffer, size_t size)
332{
Christoph Hellwig431547b2009-11-13 09:52:56 +0000333 return ext2_xattr_list(dentry, buffer, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334}
335
336/*
337 * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is
338 * not set, set it.
339 */
340static void ext2_xattr_update_super_block(struct super_block *sb)
341{
342 if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))
343 return;
344
Jan Blunckc15271f2010-04-14 14:38:38 +0200345 spin_lock(&EXT2_SB(sb)->s_lock);
Andreas Gruenbachered2908f2006-12-06 20:36:16 -0800346 EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR);
Jan Blunckc15271f2010-04-14 14:38:38 +0200347 spin_unlock(&EXT2_SB(sb)->s_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349}
350
351/*
352 * ext2_xattr_set()
353 *
Wang Sheng-Hui6e9510b2011-01-10 12:10:30 -0500354 * Create, replace or remove an extended attribute for this inode. Value
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 * is NULL to remove an existing extended attribute, and non-NULL to
356 * either replace an existing extended attribute, or create a new extended
357 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
358 * specify that an extended attribute must exist and must not exist
359 * previous to the call, respectively.
360 *
361 * Returns 0, or a negative error number on failure.
362 */
363int
364ext2_xattr_set(struct inode *inode, int name_index, const char *name,
365 const void *value, size_t value_len, int flags)
366{
367 struct super_block *sb = inode->i_sb;
368 struct buffer_head *bh = NULL;
369 struct ext2_xattr_header *header = NULL;
370 struct ext2_xattr_entry *here, *last;
371 size_t name_len, free, min_offs = sb->s_blocksize;
372 int not_found = 1, error;
373 char *end;
374
375 /*
376 * header -- Points either into bh, or to a temporarily
377 * allocated buffer.
378 * here -- The named entry found, or the place for inserting, within
379 * the block pointed to by header.
380 * last -- Points right after the last named entry within the block
381 * pointed to by header.
382 * min_offs -- The offset of the first value (values are aligned
383 * towards the end of the block).
384 * end -- Points right after the block pointed to by header.
385 */
386
387 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
388 name_index, name, value, (long)value_len);
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 if (value == NULL)
391 value_len = 0;
392 if (name == NULL)
393 return -EINVAL;
394 name_len = strlen(name);
395 if (name_len > 255 || value_len > sb->s_blocksize)
396 return -ERANGE;
397 down_write(&EXT2_I(inode)->xattr_sem);
398 if (EXT2_I(inode)->i_file_acl) {
399 /* The inode already has an extended attribute block. */
400 bh = sb_bread(sb, EXT2_I(inode)->i_file_acl);
401 error = -EIO;
402 if (!bh)
403 goto cleanup;
404 ea_bdebug(bh, "b_count=%d, refcount=%d",
405 atomic_read(&(bh->b_count)),
406 le32_to_cpu(HDR(bh)->h_refcount));
407 header = HDR(bh);
408 end = bh->b_data + bh->b_size;
409 if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
410 header->h_blocks != cpu_to_le32(1)) {
411bad_block: ext2_error(sb, "ext2_xattr_set",
412 "inode %ld: bad block %d", inode->i_ino,
413 EXT2_I(inode)->i_file_acl);
414 error = -EIO;
415 goto cleanup;
416 }
417 /* Find the named attribute. */
418 here = FIRST_ENTRY(bh);
419 while (!IS_LAST_ENTRY(here)) {
420 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here);
421 if ((char *)next >= end)
422 goto bad_block;
423 if (!here->e_value_block && here->e_value_size) {
424 size_t offs = le16_to_cpu(here->e_value_offs);
425 if (offs < min_offs)
426 min_offs = offs;
427 }
428 not_found = name_index - here->e_name_index;
429 if (!not_found)
430 not_found = name_len - here->e_name_len;
431 if (!not_found)
432 not_found = memcmp(name, here->e_name,name_len);
433 if (not_found <= 0)
434 break;
435 here = next;
436 }
437 last = here;
438 /* We still need to compute min_offs and last. */
439 while (!IS_LAST_ENTRY(last)) {
440 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last);
441 if ((char *)next >= end)
442 goto bad_block;
443 if (!last->e_value_block && last->e_value_size) {
444 size_t offs = le16_to_cpu(last->e_value_offs);
445 if (offs < min_offs)
446 min_offs = offs;
447 }
448 last = next;
449 }
450
451 /* Check whether we have enough space left. */
452 free = min_offs - ((char*)last - (char*)header) - sizeof(__u32);
453 } else {
454 /* We will use a new extended attribute block. */
455 free = sb->s_blocksize -
456 sizeof(struct ext2_xattr_header) - sizeof(__u32);
457 here = last = NULL; /* avoid gcc uninitialized warning. */
458 }
459
460 if (not_found) {
461 /* Request to remove a nonexistent attribute? */
462 error = -ENODATA;
463 if (flags & XATTR_REPLACE)
464 goto cleanup;
465 error = 0;
466 if (value == NULL)
467 goto cleanup;
468 } else {
469 /* Request to create an existing attribute? */
470 error = -EEXIST;
471 if (flags & XATTR_CREATE)
472 goto cleanup;
473 if (!here->e_value_block && here->e_value_size) {
474 size_t size = le32_to_cpu(here->e_value_size);
475
476 if (le16_to_cpu(here->e_value_offs) + size >
477 sb->s_blocksize || size > sb->s_blocksize)
478 goto bad_block;
479 free += EXT2_XATTR_SIZE(size);
480 }
481 free += EXT2_XATTR_LEN(name_len);
482 }
483 error = -ENOSPC;
484 if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len))
485 goto cleanup;
486
487 /* Here we know that we can set the new attribute. */
488
489 if (header) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 /* assert(header == HDR(bh)); */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 lock_buffer(bh);
492 if (header->h_refcount == cpu_to_le32(1)) {
Jan Karabe0726d2016-02-22 11:56:38 -0500493 __u32 hash = le32_to_cpu(header->h_hash);
494
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 ea_bdebug(bh, "modifying in-place");
Jan Karabe0726d2016-02-22 11:56:38 -0500496 /*
497 * This must happen under buffer lock for
498 * ext2_xattr_set2() to reliably detect modified block
499 */
Tahsin Erdogan47387402017-06-22 11:28:55 -0400500 mb_cache_entry_delete(EA_BLOCK_CACHE(inode), hash,
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400501 bh->b_blocknr);
Jan Karabe0726d2016-02-22 11:56:38 -0500502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 /* keep the buffer locked while modifying it. */
504 } else {
505 int offset;
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 unlock_buffer(bh);
508 ea_bdebug(bh, "cloning");
509 header = kmalloc(bh->b_size, GFP_KERNEL);
510 error = -ENOMEM;
511 if (header == NULL)
512 goto cleanup;
513 memcpy(header, HDR(bh), bh->b_size);
514 header->h_refcount = cpu_to_le32(1);
515
516 offset = (char *)here - bh->b_data;
517 here = ENTRY((char *)header + offset);
518 offset = (char *)last - bh->b_data;
519 last = ENTRY((char *)header + offset);
520 }
521 } else {
522 /* Allocate a buffer where we construct the new block. */
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -0700523 header = kzalloc(sb->s_blocksize, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 error = -ENOMEM;
525 if (header == NULL)
526 goto cleanup;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 end = (char *)header + sb->s_blocksize;
528 header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC);
529 header->h_blocks = header->h_refcount = cpu_to_le32(1);
530 last = here = ENTRY(header+1);
531 }
532
533 /* Iff we are modifying the block in-place, bh is locked here. */
534
535 if (not_found) {
536 /* Insert the new name. */
537 size_t size = EXT2_XATTR_LEN(name_len);
538 size_t rest = (char *)last - (char *)here;
539 memmove((char *)here + size, here, rest);
540 memset(here, 0, size);
541 here->e_name_index = name_index;
542 here->e_name_len = name_len;
543 memcpy(here->e_name, name, name_len);
544 } else {
545 if (!here->e_value_block && here->e_value_size) {
546 char *first_val = (char *)header + min_offs;
547 size_t offs = le16_to_cpu(here->e_value_offs);
548 char *val = (char *)header + offs;
549 size_t size = EXT2_XATTR_SIZE(
550 le32_to_cpu(here->e_value_size));
551
552 if (size == EXT2_XATTR_SIZE(value_len)) {
553 /* The old and the new value have the same
554 size. Just replace. */
555 here->e_value_size = cpu_to_le32(value_len);
556 memset(val + size - EXT2_XATTR_PAD, 0,
557 EXT2_XATTR_PAD); /* Clear pad bytes. */
558 memcpy(val, value, value_len);
559 goto skip_replace;
560 }
561
562 /* Remove the old value. */
563 memmove(first_val + size, first_val, val - first_val);
564 memset(first_val, 0, size);
565 here->e_value_offs = 0;
566 min_offs += size;
567
568 /* Adjust all value offsets. */
569 last = ENTRY(header+1);
570 while (!IS_LAST_ENTRY(last)) {
571 size_t o = le16_to_cpu(last->e_value_offs);
572 if (!last->e_value_block && o < offs)
573 last->e_value_offs =
574 cpu_to_le16(o + size);
575 last = EXT2_XATTR_NEXT(last);
576 }
577 }
578 if (value == NULL) {
579 /* Remove the old name. */
580 size_t size = EXT2_XATTR_LEN(name_len);
581 last = ENTRY((char *)last - size);
582 memmove(here, (char*)here + size,
583 (char*)last - (char*)here);
584 memset(last, 0, size);
585 }
586 }
587
588 if (value != NULL) {
589 /* Insert the new value. */
590 here->e_value_size = cpu_to_le32(value_len);
591 if (value_len) {
592 size_t size = EXT2_XATTR_SIZE(value_len);
593 char *val = (char *)header + min_offs - size;
594 here->e_value_offs =
595 cpu_to_le16((char *)val - (char *)header);
596 memset(val + size - EXT2_XATTR_PAD, 0,
597 EXT2_XATTR_PAD); /* Clear the pad bytes. */
598 memcpy(val, value, value_len);
599 }
600 }
601
602skip_replace:
603 if (IS_LAST_ENTRY(ENTRY(header+1))) {
604 /* This block is now empty. */
605 if (bh && header == HDR(bh))
606 unlock_buffer(bh); /* we were modifying in-place. */
607 error = ext2_xattr_set2(inode, bh, NULL);
608 } else {
609 ext2_xattr_rehash(header, here);
610 if (bh && header == HDR(bh))
611 unlock_buffer(bh); /* we were modifying in-place. */
612 error = ext2_xattr_set2(inode, bh, header);
613 }
614
615cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (!(bh && header == HDR(bh)))
617 kfree(header);
Pan Bian086d1f62018-11-25 08:58:02 +0800618 brelse(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 up_write(&EXT2_I(inode)->xattr_sem);
620
621 return error;
622}
623
624/*
625 * Second half of ext2_xattr_set(): Update the file system.
626 */
627static int
628ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
629 struct ext2_xattr_header *header)
630{
631 struct super_block *sb = inode->i_sb;
632 struct buffer_head *new_bh = NULL;
633 int error;
Tahsin Erdogan47387402017-06-22 11:28:55 -0400634 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635
636 if (header) {
637 new_bh = ext2_xattr_cache_find(inode, header);
638 if (new_bh) {
639 /* We found an identical block in the cache. */
640 if (new_bh == old_bh) {
641 ea_bdebug(new_bh, "keeping this block");
642 } else {
643 /* The old block is released after updating
644 the inode. */
645 ea_bdebug(new_bh, "reusing block");
646
Christoph Hellwig5dd40562010-03-03 09:05:00 -0500647 error = dquot_alloc_block(inode, 1);
648 if (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 unlock_buffer(new_bh);
650 goto cleanup;
651 }
Marcin Slusarzfba4d392008-04-28 02:15:59 -0700652 le32_add_cpu(&HDR(new_bh)->h_refcount, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 ea_bdebug(new_bh, "refcount now=%d",
654 le32_to_cpu(HDR(new_bh)->h_refcount));
655 }
656 unlock_buffer(new_bh);
657 } else if (old_bh && header == HDR(old_bh)) {
658 /* Keep this block. No need to lock the block as we
659 don't need to change the reference count. */
660 new_bh = old_bh;
661 get_bh(new_bh);
Tahsin Erdogan47387402017-06-22 11:28:55 -0400662 ext2_xattr_cache_insert(ea_block_cache, new_bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 } else {
664 /* We need to allocate a new block */
Akinobu Mita24097d12008-04-28 02:16:01 -0700665 ext2_fsblk_t goal = ext2_group_first_block_no(sb,
666 EXT2_I(inode)->i_block_group);
Martin J. Bligha686cd82007-10-16 23:30:46 -0700667 int block = ext2_new_block(inode, goal, &error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 if (error)
669 goto cleanup;
670 ea_idebug(inode, "creating block %d", block);
671
672 new_bh = sb_getblk(sb, block);
Wang Shilong2b0542a2013-01-12 01:34:50 -0800673 if (unlikely(!new_bh)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 ext2_free_blocks(inode, block, 1);
Al Viroaddacc72010-07-22 01:19:42 +0400675 mark_inode_dirty(inode);
Wang Shilongab6a7732013-01-15 21:19:06 -0800676 error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 goto cleanup;
678 }
679 lock_buffer(new_bh);
680 memcpy(new_bh->b_data, header, new_bh->b_size);
681 set_buffer_uptodate(new_bh);
682 unlock_buffer(new_bh);
Tahsin Erdogan47387402017-06-22 11:28:55 -0400683 ext2_xattr_cache_insert(ea_block_cache, new_bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684
685 ext2_xattr_update_super_block(sb);
686 }
687 mark_buffer_dirty(new_bh);
688 if (IS_SYNC(inode)) {
689 sync_dirty_buffer(new_bh);
690 error = -EIO;
691 if (buffer_req(new_bh) && !buffer_uptodate(new_bh))
692 goto cleanup;
693 }
694 }
695
696 /* Update the inode. */
697 EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
Deepa Dinamani02027d42016-09-14 07:48:05 -0700698 inode->i_ctime = current_time(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 if (IS_SYNC(inode)) {
Christoph Hellwigc37650162010-10-06 10:48:20 +0200700 error = sync_inode_metadata(inode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 /* In case sync failed due to ENOSPC the inode was actually
702 * written (only some dirty data were not) so we just proceed
703 * as if nothing happened and cleanup the unused block */
704 if (error && error != -ENOSPC) {
Al Viro38897172010-07-22 01:13:36 +0400705 if (new_bh && new_bh != old_bh) {
706 dquot_free_block_nodirty(inode, 1);
707 mark_inode_dirty(inode);
708 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 goto cleanup;
710 }
711 } else
712 mark_inode_dirty(inode);
713
714 error = 0;
715 if (old_bh && old_bh != new_bh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 /*
717 * If there was an old block and we are no longer using it,
718 * release the old block.
719 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 lock_buffer(old_bh);
721 if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) {
Jan Karabe0726d2016-02-22 11:56:38 -0500722 __u32 hash = le32_to_cpu(HDR(old_bh)->h_hash);
723
724 /*
725 * This must happen under buffer lock for
726 * ext2_xattr_set2() to reliably detect freed block
727 */
Tahsin Erdogan47387402017-06-22 11:28:55 -0400728 mb_cache_entry_delete(ea_block_cache, hash,
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400729 old_bh->b_blocknr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 /* Free the old block. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 ea_bdebug(old_bh, "freeing");
732 ext2_free_blocks(inode, old_bh->b_blocknr, 1);
Al Viroaddacc72010-07-22 01:19:42 +0400733 mark_inode_dirty(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 /* We let our caller release old_bh, so we
735 * need to duplicate the buffer before. */
736 get_bh(old_bh);
737 bforget(old_bh);
738 } else {
739 /* Decrement the refcount only. */
Marcin Slusarzfba4d392008-04-28 02:15:59 -0700740 le32_add_cpu(&HDR(old_bh)->h_refcount, -1);
Al Viro38897172010-07-22 01:13:36 +0400741 dquot_free_block_nodirty(inode, 1);
742 mark_inode_dirty(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 mark_buffer_dirty(old_bh);
744 ea_bdebug(old_bh, "refcount now=%d",
745 le32_to_cpu(HDR(old_bh)->h_refcount));
746 }
747 unlock_buffer(old_bh);
748 }
749
750cleanup:
751 brelse(new_bh);
752
753 return error;
754}
755
756/*
757 * ext2_xattr_delete_inode()
758 *
759 * Free extended attribute resources associated with this inode. This
760 * is called immediately before an inode is freed.
761 */
762void
763ext2_xattr_delete_inode(struct inode *inode)
764{
765 struct buffer_head *bh = NULL;
Carlos Maiolinoff0031d2016-07-05 22:02:41 -0400766 struct ext2_sb_info *sbi = EXT2_SB(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
768 down_write(&EXT2_I(inode)->xattr_sem);
769 if (!EXT2_I(inode)->i_file_acl)
770 goto cleanup;
Carlos Maiolinoff0031d2016-07-05 22:02:41 -0400771
772 if (!ext2_data_block_valid(sbi, EXT2_I(inode)->i_file_acl, 0)) {
773 ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
774 "inode %ld: xattr block %d is out of data blocks range",
775 inode->i_ino, EXT2_I(inode)->i_file_acl);
776 goto cleanup;
777 }
778
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
780 if (!bh) {
781 ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
782 "inode %ld: block %d read error", inode->i_ino,
783 EXT2_I(inode)->i_file_acl);
784 goto cleanup;
785 }
786 ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count)));
787 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
788 HDR(bh)->h_blocks != cpu_to_le32(1)) {
789 ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
790 "inode %ld: bad block %d", inode->i_ino,
791 EXT2_I(inode)->i_file_acl);
792 goto cleanup;
793 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 lock_buffer(bh);
795 if (HDR(bh)->h_refcount == cpu_to_le32(1)) {
Jan Karabe0726d2016-02-22 11:56:38 -0500796 __u32 hash = le32_to_cpu(HDR(bh)->h_hash);
797
798 /*
799 * This must happen under buffer lock for ext2_xattr_set2() to
800 * reliably detect freed block
801 */
Tahsin Erdogan47387402017-06-22 11:28:55 -0400802 mb_cache_entry_delete(EA_BLOCK_CACHE(inode), hash,
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400803 bh->b_blocknr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
805 get_bh(bh);
806 bforget(bh);
Peter Staubachb2f49032006-02-17 13:52:36 -0800807 unlock_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 } else {
Marcin Slusarzfba4d392008-04-28 02:15:59 -0700809 le32_add_cpu(&HDR(bh)->h_refcount, -1);
Peter Staubachb2f49032006-02-17 13:52:36 -0800810 ea_bdebug(bh, "refcount now=%d",
811 le32_to_cpu(HDR(bh)->h_refcount));
812 unlock_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 mark_buffer_dirty(bh);
814 if (IS_SYNC(inode))
815 sync_dirty_buffer(bh);
Al Viro38897172010-07-22 01:13:36 +0400816 dquot_free_block_nodirty(inode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 EXT2_I(inode)->i_file_acl = 0;
819
820cleanup:
821 brelse(bh);
822 up_write(&EXT2_I(inode)->xattr_sem);
823}
824
825/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 * ext2_xattr_cache_insert()
827 *
828 * Create a new entry in the extended attribute cache, and insert
829 * it unless such an entry is already in the cache.
830 *
831 * Returns 0, or a negative error number on failure.
832 */
833static int
Jan Kara7a2508e2016-02-22 22:35:22 -0500834ext2_xattr_cache_insert(struct mb_cache *cache, struct buffer_head *bh)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835{
836 __u32 hash = le32_to_cpu(HDR(bh)->h_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 int error;
838
Andreas Gruenbacher6048c642016-02-22 22:44:04 -0500839 error = mb_cache_entry_create(cache, GFP_NOFS, hash, bh->b_blocknr, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 if (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 if (error == -EBUSY) {
Jan Karab2c5f602020-03-17 12:40:02 +0100842 ea_bdebug(bh, "already in cache");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 error = 0;
844 }
Jan Karabe0726d2016-02-22 11:56:38 -0500845 } else
846 ea_bdebug(bh, "inserting [%x]", (int)hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 return error;
848}
849
850/*
851 * ext2_xattr_cmp()
852 *
853 * Compare two extended attribute blocks for equality.
854 *
855 * Returns 0 if the blocks are equal, 1 if they differ, and
856 * a negative error number on errors.
857 */
858static int
859ext2_xattr_cmp(struct ext2_xattr_header *header1,
860 struct ext2_xattr_header *header2)
861{
862 struct ext2_xattr_entry *entry1, *entry2;
863
864 entry1 = ENTRY(header1+1);
865 entry2 = ENTRY(header2+1);
866 while (!IS_LAST_ENTRY(entry1)) {
867 if (IS_LAST_ENTRY(entry2))
868 return 1;
869 if (entry1->e_hash != entry2->e_hash ||
870 entry1->e_name_index != entry2->e_name_index ||
871 entry1->e_name_len != entry2->e_name_len ||
872 entry1->e_value_size != entry2->e_value_size ||
873 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
874 return 1;
875 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
876 return -EIO;
877 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
878 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
879 le32_to_cpu(entry1->e_value_size)))
880 return 1;
881
882 entry1 = EXT2_XATTR_NEXT(entry1);
883 entry2 = EXT2_XATTR_NEXT(entry2);
884 }
885 if (!IS_LAST_ENTRY(entry2))
886 return 1;
887 return 0;
888}
889
890/*
891 * ext2_xattr_cache_find()
892 *
893 * Find an identical extended attribute block.
894 *
895 * Returns a locked buffer head to the block found, or NULL if such
896 * a block was not found or an error occurred.
897 */
898static struct buffer_head *
899ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
900{
901 __u32 hash = le32_to_cpu(header->h_hash);
Jan Kara7a2508e2016-02-22 22:35:22 -0500902 struct mb_cache_entry *ce;
Tahsin Erdogan47387402017-06-22 11:28:55 -0400903 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904
905 if (!header->h_hash)
906 return NULL; /* never share */
907 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
908again:
Tahsin Erdogan47387402017-06-22 11:28:55 -0400909 ce = mb_cache_entry_find_first(ea_block_cache, hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 while (ce) {
911 struct buffer_head *bh;
912
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400913 bh = sb_bread(inode->i_sb, ce->e_value);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 if (!bh) {
915 ext2_error(inode->i_sb, "ext2_xattr_cache_find",
916 "inode %ld: block %ld read error",
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400917 inode->i_ino, (unsigned long) ce->e_value);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 } else {
919 lock_buffer(bh);
Jan Karabe0726d2016-02-22 11:56:38 -0500920 /*
921 * We have to be careful about races with freeing or
922 * rehashing of xattr block. Once we hold buffer lock
923 * xattr block's state is stable so we can check
924 * whether the block got freed / rehashed or not.
925 * Since we unhash mbcache entry under buffer lock when
926 * freeing / rehashing xattr block, checking whether
927 * entry is still hashed is reliable.
928 */
929 if (hlist_bl_unhashed(&ce->e_hash_list)) {
Tahsin Erdogan47387402017-06-22 11:28:55 -0400930 mb_cache_entry_put(ea_block_cache, ce);
Jan Karabe0726d2016-02-22 11:56:38 -0500931 unlock_buffer(bh);
932 brelse(bh);
933 goto again;
934 } else if (le32_to_cpu(HDR(bh)->h_refcount) >
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 EXT2_XATTR_REFCOUNT_MAX) {
936 ea_idebug(inode, "block %ld refcount %d>%d",
Tahsin Erdoganc07dfcb2017-06-22 10:29:53 -0400937 (unsigned long) ce->e_value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 le32_to_cpu(HDR(bh)->h_refcount),
939 EXT2_XATTR_REFCOUNT_MAX);
940 } else if (!ext2_xattr_cmp(header, HDR(bh))) {
941 ea_bdebug(bh, "b_count=%d",
942 atomic_read(&(bh->b_count)));
Tahsin Erdogan47387402017-06-22 11:28:55 -0400943 mb_cache_entry_touch(ea_block_cache, ce);
944 mb_cache_entry_put(ea_block_cache, ce);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 return bh;
946 }
947 unlock_buffer(bh);
948 brelse(bh);
949 }
Tahsin Erdogan47387402017-06-22 11:28:55 -0400950 ce = mb_cache_entry_find_next(ea_block_cache, ce);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 }
952 return NULL;
953}
954
955#define NAME_HASH_SHIFT 5
956#define VALUE_HASH_SHIFT 16
957
958/*
959 * ext2_xattr_hash_entry()
960 *
961 * Compute the hash of an extended attribute.
962 */
963static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header,
964 struct ext2_xattr_entry *entry)
965{
966 __u32 hash = 0;
967 char *name = entry->e_name;
968 int n;
969
970 for (n=0; n < entry->e_name_len; n++) {
971 hash = (hash << NAME_HASH_SHIFT) ^
972 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
973 *name++;
974 }
975
976 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
977 __le32 *value = (__le32 *)((char *)header +
978 le16_to_cpu(entry->e_value_offs));
979 for (n = (le32_to_cpu(entry->e_value_size) +
980 EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) {
981 hash = (hash << VALUE_HASH_SHIFT) ^
982 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
983 le32_to_cpu(*value++);
984 }
985 }
986 entry->e_hash = cpu_to_le32(hash);
987}
988
989#undef NAME_HASH_SHIFT
990#undef VALUE_HASH_SHIFT
991
992#define BLOCK_HASH_SHIFT 16
993
994/*
995 * ext2_xattr_rehash()
996 *
997 * Re-compute the extended attribute hash value after an entry has changed.
998 */
999static void ext2_xattr_rehash(struct ext2_xattr_header *header,
1000 struct ext2_xattr_entry *entry)
1001{
1002 struct ext2_xattr_entry *here;
1003 __u32 hash = 0;
1004
1005 ext2_xattr_hash_entry(header, entry);
1006 here = ENTRY(header+1);
1007 while (!IS_LAST_ENTRY(here)) {
1008 if (!here->e_hash) {
1009 /* Block is not shared if an entry's hash value == 0 */
1010 hash = 0;
1011 break;
1012 }
1013 hash = (hash << BLOCK_HASH_SHIFT) ^
1014 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1015 le32_to_cpu(here->e_hash);
1016 here = EXT2_XATTR_NEXT(here);
1017 }
1018 header->h_hash = cpu_to_le32(hash);
1019}
1020
1021#undef BLOCK_HASH_SHIFT
1022
Jan Karabe0726d2016-02-22 11:56:38 -05001023#define HASH_BUCKET_BITS 10
1024
Jan Kara7a2508e2016-02-22 22:35:22 -05001025struct mb_cache *ext2_xattr_create_cache(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026{
Jan Kara7a2508e2016-02-22 22:35:22 -05001027 return mb_cache_create(HASH_BUCKET_BITS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028}
1029
Jan Kara7a2508e2016-02-22 22:35:22 -05001030void ext2_xattr_destroy_cache(struct mb_cache *cache)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031{
Jan Karabe0726d2016-02-22 11:56:38 -05001032 if (cache)
Jan Kara7a2508e2016-02-22 22:35:22 -05001033 mb_cache_destroy(cache);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034}