1/*
   2 * linux/fs/ext4/xattr.c
   3 *
   4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5 *
   6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   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 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13 *  and Andreas Gruenbacher <agruen@suse.de>.
  14 */
  15
  16/*
  17 * Extended attributes are stored directly in inodes (on file systems with
  18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19 * field contains the block number if an inode uses an additional block. All
  20 * attributes must fit in the inode and one additional block. Blocks that
  21 * contain the identical set of attributes may be shared among several inodes.
  22 * Identical blocks are detected by keeping a cache of blocks that have
  23 * recently been accessed.
  24 *
  25 * The attributes in inodes and on blocks have a different header; the entries
  26 * are stored in the same format:
  27 *
  28 *   +------------------+
  29 *   | header           |
  30 *   | entry 1          | |
  31 *   | entry 2          | | growing downwards
  32 *   | entry 3          | v
  33 *   | four null bytes  |
  34 *   | . . .            |
  35 *   | value 1          | ^
  36 *   | value 3          | | growing upwards
  37 *   | value 2          | |
  38 *   +------------------+
  39 *
  40 * The header is followed by multiple entry descriptors. In disk blocks, the
  41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42 * attribute values are aligned to the end of the block in no specific order.
  43 *
  44 * Locking strategy
  45 * ----------------
  46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47 * EA blocks are only changed if they are exclusive to an inode, so
  48 * holding xattr_sem also means that nothing but the EA block's reference
  49 * count can change. Multiple writers to the same block are synchronized
  50 * by the buffer lock.
  51 */
  52
  53#include <linux/init.h>
  54#include <linux/fs.h>
  55#include <linux/slab.h>
  56#include <linux/mbcache.h>
  57#include <linux/quotaops.h>
  58#include "ext4_jbd2.h"
  59#include "ext4.h"
  60#include "xattr.h"
  61#include "acl.h"
  62
  63#ifdef EXT4_XATTR_DEBUG
  64# define ea_idebug(inode, f...) do { \
  65		printk(KERN_DEBUG "inode %s:%lu: ", \
  66			inode->i_sb->s_id, inode->i_ino); \
  67		printk(f); \
  68		printk("\n"); \
  69	} while (0)
  70# define ea_bdebug(bh, f...) do { \
  71		printk(KERN_DEBUG "block %pg:%lu: ",		   \
  72		       bh->b_bdev, (unsigned long) bh->b_blocknr); \
  73		printk(f); \
  74		printk("\n"); \
  75	} while (0)
  76#else
  77# define ea_idebug(inode, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
  78# define ea_bdebug(bh, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
  79#endif
  80
  81static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
  82static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  83						 struct ext4_xattr_header *,
  84						 struct mb_cache_entry **);
  85static void ext4_xattr_rehash(struct ext4_xattr_header *,
  86			      struct ext4_xattr_entry *);
  87static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  88			   size_t buffer_size);
  89
  90static const struct xattr_handler *ext4_xattr_handler_map[] = {
  91	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
  92#ifdef CONFIG_EXT4_FS_POSIX_ACL
  93	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  94	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  95#endif
  96	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
  97#ifdef CONFIG_EXT4_FS_SECURITY
  98	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
  99#endif
 100};
 101
 102const struct xattr_handler *ext4_xattr_handlers[] = {
 103	&ext4_xattr_user_handler,
 104	&ext4_xattr_trusted_handler,
 105#ifdef CONFIG_EXT4_FS_POSIX_ACL
 106	&posix_acl_access_xattr_handler,
 107	&posix_acl_default_xattr_handler,
 108#endif
 109#ifdef CONFIG_EXT4_FS_SECURITY
 110	&ext4_xattr_security_handler,
 111#endif
 112	NULL
 113};
 114
 115#define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 116				inode->i_sb->s_fs_info)->s_mb_cache)
 117
 118static __le32 ext4_xattr_block_csum(struct inode *inode,
 119				    sector_t block_nr,
 120				    struct ext4_xattr_header *hdr)
 121{
 122	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 123	__u32 csum;
 124	__le32 save_csum;
 125	__le64 dsk_block_nr = cpu_to_le64(block_nr);
 
 
 126
 127	save_csum = hdr->h_checksum;
 128	hdr->h_checksum = 0;
 129	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 130			   sizeof(dsk_block_nr));
 131	csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
 132			   EXT4_BLOCK_SIZE(inode->i_sb));
 
 
 
 133
 134	hdr->h_checksum = save_csum;
 135	return cpu_to_le32(csum);
 136}
 137
 138static int ext4_xattr_block_csum_verify(struct inode *inode,
 139					sector_t block_nr,
 140					struct ext4_xattr_header *hdr)
 141{
 142	if (ext4_has_metadata_csum(inode->i_sb) &&
 143	    (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 144		return 0;
 145	return 1;
 146}
 147
 148static void ext4_xattr_block_csum_set(struct inode *inode,
 149				      sector_t block_nr,
 150				      struct ext4_xattr_header *hdr)
 151{
 152	if (!ext4_has_metadata_csum(inode->i_sb))
 153		return;
 154
 155	hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 
 
 
 
 
 
 156}
 157
 158static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 159						struct inode *inode,
 160						struct buffer_head *bh)
 161{
 162	ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 163	return ext4_handle_dirty_metadata(handle, inode, bh);
 
 164}
 165
 166static inline const struct xattr_handler *
 167ext4_xattr_handler(int name_index)
 168{
 169	const struct xattr_handler *handler = NULL;
 170
 171	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 172		handler = ext4_xattr_handler_map[name_index];
 173	return handler;
 174}
 175
 176/*
 177 * Inode operation listxattr()
 178 *
 179 * d_inode(dentry)->i_mutex: don't care
 180 */
 181ssize_t
 182ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 183{
 184	return ext4_xattr_list(dentry, buffer, size);
 185}
 186
 187static int
 188ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
 189		       void *value_start)
 190{
 191	struct ext4_xattr_entry *e = entry;
 192
 
 193	while (!IS_LAST_ENTRY(e)) {
 194		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 195		if ((void *)next >= end)
 196			return -EFSCORRUPTED;
 197		e = next;
 198	}
 199
 
 200	while (!IS_LAST_ENTRY(entry)) {
 201		if (entry->e_value_size != 0 &&
 202		    (value_start + le16_to_cpu(entry->e_value_offs) <
 203		     (void *)e + sizeof(__u32) ||
 204		     value_start + le16_to_cpu(entry->e_value_offs) +
 205		    le32_to_cpu(entry->e_value_size) > end))
 206			return -EFSCORRUPTED;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 207		entry = EXT4_XATTR_NEXT(entry);
 208	}
 209
 210	return 0;
 211}
 212
 213static inline int
 214ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 215{
 216	int error;
 217
 218	if (buffer_verified(bh))
 219		return 0;
 220
 221	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 222	    BHDR(bh)->h_blocks != cpu_to_le32(1))
 223		return -EFSCORRUPTED;
 224	if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 225		return -EFSBADCRC;
 226	error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
 227				       bh->b_data);
 228	if (!error)
 229		set_buffer_verified(bh);
 230	return error;
 231}
 232
 233static int
 234__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 235			 void *end, const char *function, unsigned int line)
 236{
 237	struct ext4_xattr_entry *entry = IFIRST(header);
 238	int error = -EFSCORRUPTED;
 239
 240	if (((void *) header >= end) ||
 241	    (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))
 242		goto errout;
 243	error = ext4_xattr_check_names(entry, end, entry);
 244errout:
 245	if (error)
 246		__ext4_error_inode(inode, function, line, 0,
 247				   "corrupted in-inode xattr");
 248	return error;
 249}
 250
 251#define xattr_check_inode(inode, header, end) \
 252	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 253
 254static inline int
 255ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 256{
 257	size_t value_size = le32_to_cpu(entry->e_value_size);
 258
 259	if (entry->e_value_block != 0 || value_size > size ||
 260	    le16_to_cpu(entry->e_value_offs) + value_size > size)
 261		return -EFSCORRUPTED;
 262	return 0;
 263}
 264
 265static int
 266ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 267		      const char *name, size_t size, int sorted)
 268{
 269	struct ext4_xattr_entry *entry;
 270	size_t name_len;
 271	int cmp = 1;
 272
 273	if (name == NULL)
 274		return -EINVAL;
 275	name_len = strlen(name);
 276	entry = *pentry;
 277	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 278		cmp = name_index - entry->e_name_index;
 279		if (!cmp)
 280			cmp = name_len - entry->e_name_len;
 281		if (!cmp)
 282			cmp = memcmp(name, entry->e_name, name_len);
 283		if (cmp <= 0 && (sorted || cmp == 0))
 284			break;
 285	}
 286	*pentry = entry;
 287	if (!cmp && ext4_xattr_check_entry(entry, size))
 288		return -EFSCORRUPTED;
 289	return cmp ? -ENODATA : 0;
 290}
 291
 292static int
 293ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 294		     void *buffer, size_t buffer_size)
 295{
 296	struct buffer_head *bh = NULL;
 297	struct ext4_xattr_entry *entry;
 298	size_t size;
 299	int error;
 300	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 301
 302	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 303		  name_index, name, buffer, (long)buffer_size);
 304
 305	error = -ENODATA;
 306	if (!EXT4_I(inode)->i_file_acl)
 307		goto cleanup;
 308	ea_idebug(inode, "reading block %llu",
 309		  (unsigned long long)EXT4_I(inode)->i_file_acl);
 310	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 311	if (!bh)
 312		goto cleanup;
 313	ea_bdebug(bh, "b_count=%d, refcount=%d",
 314		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 315	if (ext4_xattr_check_block(inode, bh)) {
 316bad_block:
 317		EXT4_ERROR_INODE(inode, "bad block %llu",
 318				 EXT4_I(inode)->i_file_acl);
 319		error = -EFSCORRUPTED;
 320		goto cleanup;
 321	}
 322	ext4_xattr_cache_insert(ext4_mb_cache, bh);
 323	entry = BFIRST(bh);
 324	error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 325	if (error == -EFSCORRUPTED)
 326		goto bad_block;
 327	if (error)
 328		goto cleanup;
 329	size = le32_to_cpu(entry->e_value_size);
 330	if (buffer) {
 331		error = -ERANGE;
 332		if (size > buffer_size)
 333			goto cleanup;
 334		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 335		       size);
 336	}
 337	error = size;
 338
 339cleanup:
 340	brelse(bh);
 341	return error;
 342}
 343
 344int
 345ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 346		     void *buffer, size_t buffer_size)
 347{
 348	struct ext4_xattr_ibody_header *header;
 349	struct ext4_xattr_entry *entry;
 350	struct ext4_inode *raw_inode;
 351	struct ext4_iloc iloc;
 352	size_t size;
 353	void *end;
 354	int error;
 355
 356	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 357		return -ENODATA;
 358	error = ext4_get_inode_loc(inode, &iloc);
 359	if (error)
 360		return error;
 361	raw_inode = ext4_raw_inode(&iloc);
 362	header = IHDR(inode, raw_inode);
 363	entry = IFIRST(header);
 364	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 365	error = xattr_check_inode(inode, header, end);
 366	if (error)
 367		goto cleanup;
 368	error = ext4_xattr_find_entry(&entry, name_index, name,
 369				      end - (void *)entry, 0);
 370	if (error)
 371		goto cleanup;
 372	size = le32_to_cpu(entry->e_value_size);
 373	if (buffer) {
 374		error = -ERANGE;
 375		if (size > buffer_size)
 376			goto cleanup;
 377		memcpy(buffer, (void *)IFIRST(header) +
 378		       le16_to_cpu(entry->e_value_offs), size);
 379	}
 380	error = size;
 381
 382cleanup:
 383	brelse(iloc.bh);
 384	return error;
 385}
 386
 387/*
 388 * ext4_xattr_get()
 389 *
 390 * Copy an extended attribute into the buffer
 391 * provided, or compute the buffer size required.
 392 * Buffer is NULL to compute the size of the buffer required.
 393 *
 394 * Returns a negative error number on failure, or the number of bytes
 395 * used / required on success.
 396 */
 397int
 398ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 399	       void *buffer, size_t buffer_size)
 400{
 401	int error;
 402
 403	if (strlen(name) > 255)
 404		return -ERANGE;
 405
 406	down_read(&EXT4_I(inode)->xattr_sem);
 407	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 408				     buffer_size);
 409	if (error == -ENODATA)
 410		error = ext4_xattr_block_get(inode, name_index, name, buffer,
 411					     buffer_size);
 412	up_read(&EXT4_I(inode)->xattr_sem);
 413	return error;
 414}
 415
 416static int
 417ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 418			char *buffer, size_t buffer_size)
 419{
 420	size_t rest = buffer_size;
 421
 422	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 423		const struct xattr_handler *handler =
 424			ext4_xattr_handler(entry->e_name_index);
 425
 426		if (handler && (!handler->list || handler->list(dentry))) {
 427			const char *prefix = handler->prefix ?: handler->name;
 428			size_t prefix_len = strlen(prefix);
 429			size_t size = prefix_len + entry->e_name_len + 1;
 430
 431			if (buffer) {
 432				if (size > rest)
 433					return -ERANGE;
 434				memcpy(buffer, prefix, prefix_len);
 435				buffer += prefix_len;
 436				memcpy(buffer, entry->e_name, entry->e_name_len);
 437				buffer += entry->e_name_len;
 438				*buffer++ = 0;
 439			}
 440			rest -= size;
 441		}
 442	}
 443	return buffer_size - rest;  /* total size */
 444}
 445
 446static int
 447ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 448{
 449	struct inode *inode = d_inode(dentry);
 450	struct buffer_head *bh = NULL;
 451	int error;
 452	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 453
 454	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 455		  buffer, (long)buffer_size);
 456
 457	error = 0;
 458	if (!EXT4_I(inode)->i_file_acl)
 459		goto cleanup;
 460	ea_idebug(inode, "reading block %llu",
 461		  (unsigned long long)EXT4_I(inode)->i_file_acl);
 462	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 463	error = -EIO;
 464	if (!bh)
 465		goto cleanup;
 466	ea_bdebug(bh, "b_count=%d, refcount=%d",
 467		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 468	if (ext4_xattr_check_block(inode, bh)) {
 469		EXT4_ERROR_INODE(inode, "bad block %llu",
 470				 EXT4_I(inode)->i_file_acl);
 471		error = -EFSCORRUPTED;
 472		goto cleanup;
 473	}
 474	ext4_xattr_cache_insert(ext4_mb_cache, bh);
 475	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 476
 477cleanup:
 478	brelse(bh);
 479
 480	return error;
 481}
 482
 483static int
 484ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 485{
 486	struct inode *inode = d_inode(dentry);
 487	struct ext4_xattr_ibody_header *header;
 488	struct ext4_inode *raw_inode;
 489	struct ext4_iloc iloc;
 490	void *end;
 491	int error;
 492
 493	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 494		return 0;
 495	error = ext4_get_inode_loc(inode, &iloc);
 496	if (error)
 497		return error;
 498	raw_inode = ext4_raw_inode(&iloc);
 499	header = IHDR(inode, raw_inode);
 500	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 501	error = xattr_check_inode(inode, header, end);
 502	if (error)
 503		goto cleanup;
 504	error = ext4_xattr_list_entries(dentry, IFIRST(header),
 505					buffer, buffer_size);
 506
 507cleanup:
 508	brelse(iloc.bh);
 509	return error;
 510}
 511
 512/*
 513 * ext4_xattr_list()
 514 *
 515 * Copy a list of attribute names into the buffer
 516 * provided, or compute the buffer size required.
 517 * Buffer is NULL to compute the size of the buffer required.
 518 *
 519 * Returns a negative error number on failure, or the number of bytes
 520 * used / required on success.
 521 */
 522static int
 523ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 524{
 525	int ret, ret2;
 526
 527	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 528	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 529	if (ret < 0)
 530		goto errout;
 531	if (buffer) {
 532		buffer += ret;
 533		buffer_size -= ret;
 534	}
 535	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 536	if (ret < 0)
 537		goto errout;
 538	ret += ret2;
 539errout:
 540	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 541	return ret;
 542}
 543
 544/*
 545 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 546 * not set, set it.
 547 */
 548static void ext4_xattr_update_super_block(handle_t *handle,
 549					  struct super_block *sb)
 550{
 551	if (ext4_has_feature_xattr(sb))
 552		return;
 553
 554	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 555	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 556		ext4_set_feature_xattr(sb);
 557		ext4_handle_dirty_super(handle, sb);
 558	}
 559}
 560
 561/*
 562 * Release the xattr block BH: If the reference count is > 1, decrement it;
 563 * otherwise free the block.
 564 */
 565static void
 566ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 567			 struct buffer_head *bh)
 568{
 569	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 570	u32 hash, ref;
 571	int error = 0;
 572
 573	BUFFER_TRACE(bh, "get_write_access");
 574	error = ext4_journal_get_write_access(handle, bh);
 575	if (error)
 576		goto out;
 577
 578	lock_buffer(bh);
 579	hash = le32_to_cpu(BHDR(bh)->h_hash);
 580	ref = le32_to_cpu(BHDR(bh)->h_refcount);
 581	if (ref == 1) {
 582		ea_bdebug(bh, "refcount now=0; freeing");
 583		/*
 584		 * This must happen under buffer lock for
 585		 * ext4_xattr_block_set() to reliably detect freed block
 586		 */
 587		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
 588		get_bh(bh);
 589		unlock_buffer(bh);
 590		ext4_free_blocks(handle, inode, bh, 0, 1,
 591				 EXT4_FREE_BLOCKS_METADATA |
 592				 EXT4_FREE_BLOCKS_FORGET);
 593	} else {
 594		ref--;
 595		BHDR(bh)->h_refcount = cpu_to_le32(ref);
 596		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
 597			struct mb_cache_entry *ce;
 598
 599			ce = mb_cache_entry_get(ext4_mb_cache, hash,
 600						bh->b_blocknr);
 601			if (ce) {
 602				ce->e_reusable = 1;
 603				mb_cache_entry_put(ext4_mb_cache, ce);
 604			}
 605		}
 606
 
 607		/*
 608		 * Beware of this ugliness: Releasing of xattr block references
 609		 * from different inodes can race and so we have to protect
 610		 * from a race where someone else frees the block (and releases
 611		 * its journal_head) before we are done dirtying the buffer. In
 612		 * nojournal mode this race is harmless and we actually cannot
 613		 * call ext4_handle_dirty_xattr_block() with locked buffer as
 614		 * that function can call sync_dirty_buffer() so for that case
 615		 * we handle the dirtying after unlocking the buffer.
 616		 */
 617		if (ext4_handle_valid(handle))
 618			error = ext4_handle_dirty_xattr_block(handle, inode,
 619							      bh);
 620		unlock_buffer(bh);
 621		if (!ext4_handle_valid(handle))
 622			error = ext4_handle_dirty_xattr_block(handle, inode,
 623							      bh);
 624		if (IS_SYNC(inode))
 625			ext4_handle_sync(handle);
 626		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 627		ea_bdebug(bh, "refcount now=%d; releasing",
 628			  le32_to_cpu(BHDR(bh)->h_refcount));
 629	}
 630out:
 631	ext4_std_error(inode->i_sb, error);
 632	return;
 633}
 634
 635/*
 636 * Find the available free space for EAs. This also returns the total number of
 637 * bytes used by EA entries.
 638 */
 639static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 640				    size_t *min_offs, void *base, int *total)
 641{
 642	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 643		if (!last->e_value_block && last->e_value_size) {
 644			size_t offs = le16_to_cpu(last->e_value_offs);
 645			if (offs < *min_offs)
 646				*min_offs = offs;
 647		}
 648		if (total)
 649			*total += EXT4_XATTR_LEN(last->e_name_len);
 650	}
 651	return (*min_offs - ((void *)last - base) - sizeof(__u32));
 652}
 653
 654static int
 655ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 656{
 657	struct ext4_xattr_entry *last;
 658	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 659
 660	/* Compute min_offs and last. */
 661	last = s->first;
 662	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 663		if (!last->e_value_block && last->e_value_size) {
 664			size_t offs = le16_to_cpu(last->e_value_offs);
 665			if (offs < min_offs)
 666				min_offs = offs;
 667		}
 668	}
 669	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 670	if (!s->not_found) {
 671		if (!s->here->e_value_block && s->here->e_value_size) {
 672			size_t size = le32_to_cpu(s->here->e_value_size);
 673			free += EXT4_XATTR_SIZE(size);
 674		}
 675		free += EXT4_XATTR_LEN(name_len);
 676	}
 677	if (i->value) {
 678		if (free < EXT4_XATTR_LEN(name_len) +
 679			   EXT4_XATTR_SIZE(i->value_len))
 680			return -ENOSPC;
 681	}
 682
 683	if (i->value && s->not_found) {
 684		/* Insert the new name. */
 685		size_t size = EXT4_XATTR_LEN(name_len);
 686		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 687		memmove((void *)s->here + size, s->here, rest);
 688		memset(s->here, 0, size);
 689		s->here->e_name_index = i->name_index;
 690		s->here->e_name_len = name_len;
 691		memcpy(s->here->e_name, i->name, name_len);
 692	} else {
 693		if (!s->here->e_value_block && s->here->e_value_size) {
 694			void *first_val = s->base + min_offs;
 695			size_t offs = le16_to_cpu(s->here->e_value_offs);
 696			void *val = s->base + offs;
 697			size_t size = EXT4_XATTR_SIZE(
 698				le32_to_cpu(s->here->e_value_size));
 699
 700			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 701				/* The old and the new value have the same
 702				   size. Just replace. */
 703				s->here->e_value_size =
 704					cpu_to_le32(i->value_len);
 705				if (i->value == EXT4_ZERO_XATTR_VALUE) {
 706					memset(val, 0, size);
 707				} else {
 708					/* Clear pad bytes first. */
 709					memset(val + size - EXT4_XATTR_PAD, 0,
 710					       EXT4_XATTR_PAD);
 711					memcpy(val, i->value, i->value_len);
 712				}
 713				return 0;
 714			}
 715
 716			/* Remove the old value. */
 717			memmove(first_val + size, first_val, val - first_val);
 718			memset(first_val, 0, size);
 719			s->here->e_value_size = 0;
 720			s->here->e_value_offs = 0;
 721			min_offs += size;
 722
 723			/* Adjust all value offsets. */
 724			last = s->first;
 725			while (!IS_LAST_ENTRY(last)) {
 726				size_t o = le16_to_cpu(last->e_value_offs);
 727				if (!last->e_value_block &&
 728				    last->e_value_size && o < offs)
 729					last->e_value_offs =
 730						cpu_to_le16(o + size);
 731				last = EXT4_XATTR_NEXT(last);
 732			}
 733		}
 734		if (!i->value) {
 735			/* Remove the old name. */
 736			size_t size = EXT4_XATTR_LEN(name_len);
 737			last = ENTRY((void *)last - size);
 738			memmove(s->here, (void *)s->here + size,
 739				(void *)last - (void *)s->here + sizeof(__u32));
 740			memset(last, 0, size);
 741		}
 742	}
 743
 744	if (i->value) {
 745		/* Insert the new value. */
 746		s->here->e_value_size = cpu_to_le32(i->value_len);
 747		if (i->value_len) {
 748			size_t size = EXT4_XATTR_SIZE(i->value_len);
 749			void *val = s->base + min_offs - size;
 750			s->here->e_value_offs = cpu_to_le16(min_offs - size);
 751			if (i->value == EXT4_ZERO_XATTR_VALUE) {
 752				memset(val, 0, size);
 753			} else {
 754				/* Clear the pad bytes first. */
 755				memset(val + size - EXT4_XATTR_PAD, 0,
 756				       EXT4_XATTR_PAD);
 757				memcpy(val, i->value, i->value_len);
 758			}
 759		}
 760	}
 761	return 0;
 762}
 763
 764struct ext4_xattr_block_find {
 765	struct ext4_xattr_search s;
 766	struct buffer_head *bh;
 767};
 768
 769static int
 770ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 771		      struct ext4_xattr_block_find *bs)
 772{
 773	struct super_block *sb = inode->i_sb;
 774	int error;
 775
 776	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 777		  i->name_index, i->name, i->value, (long)i->value_len);
 778
 779	if (EXT4_I(inode)->i_file_acl) {
 780		/* The inode already has an extended attribute block. */
 781		bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 782		error = -EIO;
 783		if (!bs->bh)
 784			goto cleanup;
 785		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 786			atomic_read(&(bs->bh->b_count)),
 787			le32_to_cpu(BHDR(bs->bh)->h_refcount));
 788		if (ext4_xattr_check_block(inode, bs->bh)) {
 789			EXT4_ERROR_INODE(inode, "bad block %llu",
 790					 EXT4_I(inode)->i_file_acl);
 791			error = -EFSCORRUPTED;
 792			goto cleanup;
 793		}
 794		/* Find the named attribute. */
 795		bs->s.base = BHDR(bs->bh);
 796		bs->s.first = BFIRST(bs->bh);
 797		bs->s.end = bs->bh->b_data + bs->bh->b_size;
 798		bs->s.here = bs->s.first;
 799		error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 800					      i->name, bs->bh->b_size, 1);
 801		if (error && error != -ENODATA)
 802			goto cleanup;
 803		bs->s.not_found = error;
 804	}
 805	error = 0;
 806
 807cleanup:
 808	return error;
 809}
 810
 811static int
 812ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 813		     struct ext4_xattr_info *i,
 814		     struct ext4_xattr_block_find *bs)
 815{
 816	struct super_block *sb = inode->i_sb;
 817	struct buffer_head *new_bh = NULL;
 818	struct ext4_xattr_search *s = &bs->s;
 819	struct mb_cache_entry *ce = NULL;
 820	int error = 0;
 821	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 822
 823#define header(x) ((struct ext4_xattr_header *)(x))
 824
 825	if (i->value && i->value_len > sb->s_blocksize)
 826		return -ENOSPC;
 827	if (s->base) {
 828		BUFFER_TRACE(bs->bh, "get_write_access");
 829		error = ext4_journal_get_write_access(handle, bs->bh);
 830		if (error)
 831			goto cleanup;
 832		lock_buffer(bs->bh);
 833
 834		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 835			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
 836
 837			/*
 838			 * This must happen under buffer lock for
 839			 * ext4_xattr_block_set() to reliably detect modified
 840			 * block
 841			 */
 842			mb_cache_entry_delete_block(ext4_mb_cache, hash,
 843						    bs->bh->b_blocknr);
 844			ea_bdebug(bs->bh, "modifying in-place");
 845			error = ext4_xattr_set_entry(i, s);
 846			if (!error) {
 847				if (!IS_LAST_ENTRY(s->first))
 848					ext4_xattr_rehash(header(s->base),
 849							  s->here);
 850				ext4_xattr_cache_insert(ext4_mb_cache,
 851					bs->bh);
 852			}
 
 853			unlock_buffer(bs->bh);
 854			if (error == -EFSCORRUPTED)
 855				goto bad_block;
 856			if (!error)
 857				error = ext4_handle_dirty_xattr_block(handle,
 858								      inode,
 859								      bs->bh);
 860			if (error)
 861				goto cleanup;
 862			goto inserted;
 863		} else {
 864			int offset = (char *)s->here - bs->bh->b_data;
 865
 866			unlock_buffer(bs->bh);
 867			ea_bdebug(bs->bh, "cloning");
 868			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 869			error = -ENOMEM;
 870			if (s->base == NULL)
 871				goto cleanup;
 872			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 873			s->first = ENTRY(header(s->base)+1);
 874			header(s->base)->h_refcount = cpu_to_le32(1);
 875			s->here = ENTRY(s->base + offset);
 876			s->end = s->base + bs->bh->b_size;
 877		}
 878	} else {
 879		/* Allocate a buffer where we construct the new block. */
 880		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 881		/* assert(header == s->base) */
 882		error = -ENOMEM;
 883		if (s->base == NULL)
 884			goto cleanup;
 885		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 886		header(s->base)->h_blocks = cpu_to_le32(1);
 887		header(s->base)->h_refcount = cpu_to_le32(1);
 888		s->first = ENTRY(header(s->base)+1);
 889		s->here = ENTRY(header(s->base)+1);
 890		s->end = s->base + sb->s_blocksize;
 891	}
 892
 893	error = ext4_xattr_set_entry(i, s);
 894	if (error == -EFSCORRUPTED)
 895		goto bad_block;
 896	if (error)
 897		goto cleanup;
 898	if (!IS_LAST_ENTRY(s->first))
 899		ext4_xattr_rehash(header(s->base), s->here);
 900
 901inserted:
 902	if (!IS_LAST_ENTRY(s->first)) {
 903		new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 904		if (new_bh) {
 905			/* We found an identical block in the cache. */
 906			if (new_bh == bs->bh)
 907				ea_bdebug(new_bh, "keeping");
 908			else {
 909				u32 ref;
 910
 911				/* The old block is released after updating
 912				   the inode. */
 913				error = dquot_alloc_block(inode,
 914						EXT4_C2B(EXT4_SB(sb), 1));
 915				if (error)
 916					goto cleanup;
 917				BUFFER_TRACE(new_bh, "get_write_access");
 918				error = ext4_journal_get_write_access(handle,
 919								      new_bh);
 920				if (error)
 921					goto cleanup_dquot;
 922				lock_buffer(new_bh);
 923				/*
 924				 * We have to be careful about races with
 925				 * freeing, rehashing or adding references to
 926				 * xattr block. Once we hold buffer lock xattr
 927				 * block's state is stable so we can check
 928				 * whether the block got freed / rehashed or
 929				 * not.  Since we unhash mbcache entry under
 930				 * buffer lock when freeing / rehashing xattr
 931				 * block, checking whether entry is still
 932				 * hashed is reliable. Same rules hold for
 933				 * e_reusable handling.
 934				 */
 935				if (hlist_bl_unhashed(&ce->e_hash_list) ||
 936				    !ce->e_reusable) {
 937					/*
 938					 * Undo everything and check mbcache
 939					 * again.
 940					 */
 941					unlock_buffer(new_bh);
 942					dquot_free_block(inode,
 943							 EXT4_C2B(EXT4_SB(sb),
 944								  1));
 945					brelse(new_bh);
 946					mb_cache_entry_put(ext4_mb_cache, ce);
 947					ce = NULL;
 948					new_bh = NULL;
 949					goto inserted;
 950				}
 951				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
 952				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
 953				if (ref >= EXT4_XATTR_REFCOUNT_MAX)
 954					ce->e_reusable = 0;
 955				ea_bdebug(new_bh, "reusing; refcount now=%d",
 956					  ref);
 
 957				unlock_buffer(new_bh);
 958				error = ext4_handle_dirty_xattr_block(handle,
 959								      inode,
 960								      new_bh);
 961				if (error)
 962					goto cleanup_dquot;
 963			}
 964			mb_cache_entry_touch(ext4_mb_cache, ce);
 965			mb_cache_entry_put(ext4_mb_cache, ce);
 966			ce = NULL;
 967		} else if (bs->bh && s->base == bs->bh->b_data) {
 968			/* We were modifying this block in-place. */
 969			ea_bdebug(bs->bh, "keeping this block");
 970			new_bh = bs->bh;
 971			get_bh(new_bh);
 972		} else {
 973			/* We need to allocate a new block */
 974			ext4_fsblk_t goal, block;
 975
 976			goal = ext4_group_first_block_no(sb,
 977						EXT4_I(inode)->i_block_group);
 978
 979			/* non-extent files can't have physical blocks past 2^32 */
 980			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 981				goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 982
 983			block = ext4_new_meta_blocks(handle, inode, goal, 0,
 984						     NULL, &error);
 985			if (error)
 986				goto cleanup;
 987
 988			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 989				BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 990
 991			ea_idebug(inode, "creating block %llu",
 992				  (unsigned long long)block);
 993
 994			new_bh = sb_getblk(sb, block);
 995			if (unlikely(!new_bh)) {
 996				error = -ENOMEM;
 997getblk_failed:
 998				ext4_free_blocks(handle, inode, NULL, block, 1,
 999						 EXT4_FREE_BLOCKS_METADATA);
1000				goto cleanup;
1001			}
1002			lock_buffer(new_bh);
1003			error = ext4_journal_get_create_access(handle, new_bh);
1004			if (error) {
1005				unlock_buffer(new_bh);
1006				error = -EIO;
1007				goto getblk_failed;
1008			}
1009			memcpy(new_bh->b_data, s->base, new_bh->b_size);
 
1010			set_buffer_uptodate(new_bh);
1011			unlock_buffer(new_bh);
1012			ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1013			error = ext4_handle_dirty_xattr_block(handle,
1014							      inode, new_bh);
1015			if (error)
1016				goto cleanup;
1017		}
1018	}
1019
1020	/* Update the inode. */
1021	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1022
1023	/* Drop the previous xattr block. */
1024	if (bs->bh && bs->bh != new_bh)
1025		ext4_xattr_release_block(handle, inode, bs->bh);
1026	error = 0;
1027
1028cleanup:
1029	if (ce)
1030		mb_cache_entry_put(ext4_mb_cache, ce);
1031	brelse(new_bh);
1032	if (!(bs->bh && s->base == bs->bh->b_data))
1033		kfree(s->base);
1034
1035	return error;
1036
1037cleanup_dquot:
1038	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1039	goto cleanup;
1040
1041bad_block:
1042	EXT4_ERROR_INODE(inode, "bad block %llu",
1043			 EXT4_I(inode)->i_file_acl);
1044	goto cleanup;
1045
1046#undef header
1047}
1048
1049int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1050			  struct ext4_xattr_ibody_find *is)
1051{
1052	struct ext4_xattr_ibody_header *header;
1053	struct ext4_inode *raw_inode;
1054	int error;
1055
1056	if (EXT4_I(inode)->i_extra_isize == 0)
1057		return 0;
1058	raw_inode = ext4_raw_inode(&is->iloc);
1059	header = IHDR(inode, raw_inode);
1060	is->s.base = is->s.first = IFIRST(header);
1061	is->s.here = is->s.first;
1062	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1063	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1064		error = xattr_check_inode(inode, header, is->s.end);
1065		if (error)
1066			return error;
1067		/* Find the named attribute. */
1068		error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1069					      i->name, is->s.end -
1070					      (void *)is->s.base, 0);
1071		if (error && error != -ENODATA)
1072			return error;
1073		is->s.not_found = error;
1074	}
1075	return 0;
1076}
1077
1078int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1079				struct ext4_xattr_info *i,
1080				struct ext4_xattr_ibody_find *is)
1081{
1082	struct ext4_xattr_ibody_header *header;
1083	struct ext4_xattr_search *s = &is->s;
1084	int error;
1085
1086	if (EXT4_I(inode)->i_extra_isize == 0)
1087		return -ENOSPC;
1088	error = ext4_xattr_set_entry(i, s);
1089	if (error) {
1090		if (error == -ENOSPC &&
1091		    ext4_has_inline_data(inode)) {
1092			error = ext4_try_to_evict_inline_data(handle, inode,
1093					EXT4_XATTR_LEN(strlen(i->name) +
1094					EXT4_XATTR_SIZE(i->value_len)));
1095			if (error)
1096				return error;
1097			error = ext4_xattr_ibody_find(inode, i, is);
1098			if (error)
1099				return error;
1100			error = ext4_xattr_set_entry(i, s);
1101		}
1102		if (error)
1103			return error;
1104	}
1105	header = IHDR(inode, ext4_raw_inode(&is->iloc));
1106	if (!IS_LAST_ENTRY(s->first)) {
1107		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1108		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1109	} else {
1110		header->h_magic = cpu_to_le32(0);
1111		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1112	}
1113	return 0;
1114}
1115
1116static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1117				struct ext4_xattr_info *i,
1118				struct ext4_xattr_ibody_find *is)
1119{
1120	struct ext4_xattr_ibody_header *header;
1121	struct ext4_xattr_search *s = &is->s;
1122	int error;
1123
1124	if (EXT4_I(inode)->i_extra_isize == 0)
1125		return -ENOSPC;
1126	error = ext4_xattr_set_entry(i, s);
1127	if (error)
1128		return error;
1129	header = IHDR(inode, ext4_raw_inode(&is->iloc));
1130	if (!IS_LAST_ENTRY(s->first)) {
1131		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1132		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1133	} else {
1134		header->h_magic = cpu_to_le32(0);
1135		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1136	}
1137	return 0;
1138}
1139
1140static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1141				 struct ext4_xattr_info *i)
1142{
1143	void *value;
1144
1145	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1146		return 0;
1147	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1148	return !memcmp(value, i->value, i->value_len);
1149}
1150
1151/*
1152 * ext4_xattr_set_handle()
1153 *
1154 * Create, replace or remove an extended attribute for this inode.  Value
1155 * is NULL to remove an existing extended attribute, and non-NULL to
1156 * either replace an existing extended attribute, or create a new extended
1157 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1158 * specify that an extended attribute must exist and must not exist
1159 * previous to the call, respectively.
1160 *
1161 * Returns 0, or a negative error number on failure.
1162 */
1163int
1164ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1165		      const char *name, const void *value, size_t value_len,
1166		      int flags)
1167{
1168	struct ext4_xattr_info i = {
1169		.name_index = name_index,
1170		.name = name,
1171		.value = value,
1172		.value_len = value_len,
1173
1174	};
1175	struct ext4_xattr_ibody_find is = {
1176		.s = { .not_found = -ENODATA, },
1177	};
1178	struct ext4_xattr_block_find bs = {
1179		.s = { .not_found = -ENODATA, },
1180	};
1181	unsigned long no_expand;
1182	int error;
1183
1184	if (!name)
1185		return -EINVAL;
1186	if (strlen(name) > 255)
1187		return -ERANGE;
1188	down_write(&EXT4_I(inode)->xattr_sem);
1189	no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1190	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1191
1192	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1193	if (error)
1194		goto cleanup;
1195
1196	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1197		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1198		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1199		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1200	}
1201
1202	error = ext4_xattr_ibody_find(inode, &i, &is);
1203	if (error)
1204		goto cleanup;
1205	if (is.s.not_found)
1206		error = ext4_xattr_block_find(inode, &i, &bs);
1207	if (error)
1208		goto cleanup;
1209	if (is.s.not_found && bs.s.not_found) {
1210		error = -ENODATA;
1211		if (flags & XATTR_REPLACE)
1212			goto cleanup;
1213		error = 0;
1214		if (!value)
1215			goto cleanup;
1216	} else {
1217		error = -EEXIST;
1218		if (flags & XATTR_CREATE)
1219			goto cleanup;
1220	}
1221	if (!value) {
1222		if (!is.s.not_found)
1223			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1224		else if (!bs.s.not_found)
1225			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1226	} else {
1227		error = 0;
1228		/* Xattr value did not change? Save us some work and bail out */
1229		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1230			goto cleanup;
1231		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1232			goto cleanup;
1233
1234		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1235		if (!error && !bs.s.not_found) {
1236			i.value = NULL;
1237			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1238		} else if (error == -ENOSPC) {
1239			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1240				error = ext4_xattr_block_find(inode, &i, &bs);
1241				if (error)
1242					goto cleanup;
1243			}
1244			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1245			if (error)
1246				goto cleanup;
1247			if (!is.s.not_found) {
1248				i.value = NULL;
1249				error = ext4_xattr_ibody_set(handle, inode, &i,
1250							     &is);
1251			}
1252		}
1253	}
1254	if (!error) {
1255		ext4_xattr_update_super_block(handle, inode->i_sb);
1256		inode->i_ctime = ext4_current_time(inode);
1257		if (!value)
1258			ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1259		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1260		/*
1261		 * The bh is consumed by ext4_mark_iloc_dirty, even with
1262		 * error != 0.
1263		 */
1264		is.iloc.bh = NULL;
1265		if (IS_SYNC(inode))
1266			ext4_handle_sync(handle);
1267	}
1268
1269cleanup:
1270	brelse(is.iloc.bh);
1271	brelse(bs.bh);
1272	if (no_expand == 0)
1273		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1274	up_write(&EXT4_I(inode)->xattr_sem);
1275	return error;
1276}
1277
1278/*
1279 * ext4_xattr_set()
1280 *
1281 * Like ext4_xattr_set_handle, but start from an inode. This extended
1282 * attribute modification is a filesystem transaction by itself.
1283 *
1284 * Returns 0, or a negative error number on failure.
1285 */
1286int
1287ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1288	       const void *value, size_t value_len, int flags)
1289{
1290	handle_t *handle;
1291	int error, retries = 0;
1292	int credits = ext4_jbd2_credits_xattr(inode);
1293
1294retry:
1295	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1296	if (IS_ERR(handle)) {
1297		error = PTR_ERR(handle);
1298	} else {
1299		int error2;
1300
1301		error = ext4_xattr_set_handle(handle, inode, name_index, name,
1302					      value, value_len, flags);
1303		error2 = ext4_journal_stop(handle);
1304		if (error == -ENOSPC &&
1305		    ext4_should_retry_alloc(inode->i_sb, &retries))
1306			goto retry;
1307		if (error == 0)
1308			error = error2;
1309	}
1310
1311	return error;
1312}
1313
1314/*
1315 * Shift the EA entries in the inode to create space for the increased
1316 * i_extra_isize.
1317 */
1318static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1319				     int value_offs_shift, void *to,
1320				     void *from, size_t n, int blocksize)
1321{
1322	struct ext4_xattr_entry *last = entry;
1323	int new_offs;
1324
 
 
 
1325	/* Adjust the value offsets of the entries */
1326	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1327		if (!last->e_value_block && last->e_value_size) {
1328			new_offs = le16_to_cpu(last->e_value_offs) +
1329							value_offs_shift;
1330			BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1331				 > blocksize);
1332			last->e_value_offs = cpu_to_le16(new_offs);
1333		}
1334	}
1335	/* Shift the entries by n bytes */
1336	memmove(to, from, n);
1337}
1338
1339/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1340 * Expand an inode by new_extra_isize bytes when EAs are present.
1341 * Returns 0 on success or negative error number on failure.
1342 */
1343int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1344			       struct ext4_inode *raw_inode, handle_t *handle)
1345{
1346	struct ext4_xattr_ibody_header *header;
1347	struct ext4_xattr_entry *entry, *last, *first;
1348	struct buffer_head *bh = NULL;
1349	struct ext4_xattr_ibody_find *is = NULL;
1350	struct ext4_xattr_block_find *bs = NULL;
1351	char *buffer = NULL, *b_entry_name = NULL;
1352	size_t min_offs, free;
1353	int total_ino;
1354	void *base, *start, *end;
1355	int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1356	int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
 
 
1357
1358	down_write(&EXT4_I(inode)->xattr_sem);
1359retry:
1360	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1361		up_write(&EXT4_I(inode)->xattr_sem);
1362		return 0;
1363	}
 
 
 
 
1364
1365	header = IHDR(inode, raw_inode);
1366	entry = IFIRST(header);
1367
1368	/*
1369	 * Check if enough free space is available in the inode to shift the
1370	 * entries ahead by new_extra_isize.
1371	 */
1372
1373	base = start = entry;
1374	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1375	min_offs = end - base;
1376	last = entry;
1377	total_ino = sizeof(struct ext4_xattr_ibody_header);
1378
1379	error = xattr_check_inode(inode, header, end);
1380	if (error)
1381		goto cleanup;
1382
1383	free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1384	if (free >= new_extra_isize) {
1385		entry = IFIRST(header);
1386		ext4_xattr_shift_entries(entry,	EXT4_I(inode)->i_extra_isize
1387				- new_extra_isize, (void *)raw_inode +
1388				EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1389				(void *)header, total_ino,
1390				inode->i_sb->s_blocksize);
1391		EXT4_I(inode)->i_extra_isize = new_extra_isize;
1392		error = 0;
1393		goto cleanup;
1394	}
1395
1396	/*
1397	 * Enough free space isn't available in the inode, check if
1398	 * EA block can hold new_extra_isize bytes.
1399	 */
1400	if (EXT4_I(inode)->i_file_acl) {
1401		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1402		error = -EIO;
1403		if (!bh)
1404			goto cleanup;
1405		if (ext4_xattr_check_block(inode, bh)) {
1406			EXT4_ERROR_INODE(inode, "bad block %llu",
1407					 EXT4_I(inode)->i_file_acl);
1408			error = -EFSCORRUPTED;
1409			goto cleanup;
1410		}
1411		base = BHDR(bh);
1412		first = BFIRST(bh);
1413		end = bh->b_data + bh->b_size;
1414		min_offs = end - base;
1415		free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1416		if (free < new_extra_isize) {
 
1417			if (!tried_min_extra_isize && s_min_extra_isize) {
1418				tried_min_extra_isize++;
1419				new_extra_isize = s_min_extra_isize;
1420				brelse(bh);
1421				goto retry;
1422			}
1423			error = -1;
1424			goto cleanup;
1425		}
1426	} else {
1427		free = inode->i_sb->s_blocksize;
1428	}
1429
1430	while (new_extra_isize > 0) {
1431		size_t offs, size, entry_size;
1432		struct ext4_xattr_entry *small_entry = NULL;
1433		struct ext4_xattr_info i = {
1434			.value = NULL,
1435			.value_len = 0,
1436		};
1437		unsigned int total_size;  /* EA entry size + value size */
1438		unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1439		unsigned int min_total_size = ~0U;
1440
1441		is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1442		bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1443		if (!is || !bs) {
1444			error = -ENOMEM;
1445			goto cleanup;
1446		}
1447
1448		is->s.not_found = -ENODATA;
1449		bs->s.not_found = -ENODATA;
1450		is->iloc.bh = NULL;
1451		bs->bh = NULL;
1452
1453		last = IFIRST(header);
1454		/* Find the entry best suited to be pushed into EA block */
1455		entry = NULL;
1456		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1457			total_size =
1458			EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1459					EXT4_XATTR_LEN(last->e_name_len);
1460			if (total_size <= free && total_size < min_total_size) {
1461				if (total_size < new_extra_isize) {
1462					small_entry = last;
1463				} else {
1464					entry = last;
1465					min_total_size = total_size;
1466				}
1467			}
1468		}
1469
1470		if (entry == NULL) {
1471			if (small_entry) {
1472				entry = small_entry;
1473			} else {
1474				if (!tried_min_extra_isize &&
1475				    s_min_extra_isize) {
1476					tried_min_extra_isize++;
1477					new_extra_isize = s_min_extra_isize;
1478					kfree(is); is = NULL;
1479					kfree(bs); bs = NULL;
1480					brelse(bh);
1481					goto retry;
1482				}
1483				error = -1;
1484				goto cleanup;
1485			}
1486		}
1487		offs = le16_to_cpu(entry->e_value_offs);
1488		size = le32_to_cpu(entry->e_value_size);
1489		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1490		i.name_index = entry->e_name_index,
1491		buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1492		b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1493		if (!buffer || !b_entry_name) {
1494			error = -ENOMEM;
1495			goto cleanup;
1496		}
1497		/* Save the entry name and the entry value */
1498		memcpy(buffer, (void *)IFIRST(header) + offs,
1499		       EXT4_XATTR_SIZE(size));
1500		memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1501		b_entry_name[entry->e_name_len] = '\0';
1502		i.name = b_entry_name;
1503
1504		error = ext4_get_inode_loc(inode, &is->iloc);
1505		if (error)
1506			goto cleanup;
1507
1508		error = ext4_xattr_ibody_find(inode, &i, is);
1509		if (error)
1510			goto cleanup;
1511
1512		/* Remove the chosen entry from the inode */
1513		error = ext4_xattr_ibody_set(handle, inode, &i, is);
1514		if (error)
1515			goto cleanup;
1516
1517		entry = IFIRST(header);
1518		if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1519			shift_bytes = new_extra_isize;
1520		else
1521			shift_bytes = entry_size + size;
1522		/* Adjust the offsets and shift the remaining entries ahead */
1523		ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1524			shift_bytes, (void *)raw_inode +
1525			EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1526			(void *)header, total_ino - entry_size,
1527			inode->i_sb->s_blocksize);
1528
1529		extra_isize += shift_bytes;
1530		new_extra_isize -= shift_bytes;
1531		EXT4_I(inode)->i_extra_isize = extra_isize;
1532
1533		i.name = b_entry_name;
1534		i.value = buffer;
1535		i.value_len = size;
1536		error = ext4_xattr_block_find(inode, &i, bs);
1537		if (error)
1538			goto cleanup;
1539
1540		/* Add entry which was removed from the inode into the block */
1541		error = ext4_xattr_block_set(handle, inode, &i, bs);
1542		if (error)
1543			goto cleanup;
1544		kfree(b_entry_name);
1545		kfree(buffer);
1546		b_entry_name = NULL;
1547		buffer = NULL;
1548		brelse(is->iloc.bh);
1549		kfree(is);
1550		kfree(bs);
1551	}
 
 
 
 
 
 
 
1552	brelse(bh);
1553	up_write(&EXT4_I(inode)->xattr_sem);
 
1554	return 0;
1555
1556cleanup:
1557	kfree(b_entry_name);
1558	kfree(buffer);
1559	if (is)
1560		brelse(is->iloc.bh);
1561	kfree(is);
1562	kfree(bs);
1563	brelse(bh);
1564	up_write(&EXT4_I(inode)->xattr_sem);
 
 
 
 
1565	return error;
1566}
1567
1568
1569
1570/*
1571 * ext4_xattr_delete_inode()
1572 *
1573 * Free extended attribute resources associated with this inode. This
1574 * is called immediately before an inode is freed. We have exclusive
1575 * access to the inode.
1576 */
1577void
1578ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1579{
1580	struct buffer_head *bh = NULL;
1581
1582	if (!EXT4_I(inode)->i_file_acl)
1583		goto cleanup;
1584	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1585	if (!bh) {
1586		EXT4_ERROR_INODE(inode, "block %llu read error",
1587				 EXT4_I(inode)->i_file_acl);
1588		goto cleanup;
1589	}
1590	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1591	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1592		EXT4_ERROR_INODE(inode, "bad block %llu",
1593				 EXT4_I(inode)->i_file_acl);
1594		goto cleanup;
1595	}
1596	ext4_xattr_release_block(handle, inode, bh);
1597	EXT4_I(inode)->i_file_acl = 0;
1598
1599cleanup:
1600	brelse(bh);
1601}
1602
1603/*
1604 * ext4_xattr_cache_insert()
1605 *
1606 * Create a new entry in the extended attribute cache, and insert
1607 * it unless such an entry is already in the cache.
1608 *
1609 * Returns 0, or a negative error number on failure.
1610 */
1611static void
1612ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1613{
1614	struct ext4_xattr_header *header = BHDR(bh);
1615	__u32 hash = le32_to_cpu(header->h_hash);
1616	int reusable = le32_to_cpu(header->h_refcount) <
1617		       EXT4_XATTR_REFCOUNT_MAX;
1618	int error;
1619
1620	error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1621				      bh->b_blocknr, reusable);
1622	if (error) {
1623		if (error == -EBUSY)
1624			ea_bdebug(bh, "already in cache");
1625	} else
1626		ea_bdebug(bh, "inserting [%x]", (int)hash);
1627}
1628
1629/*
1630 * ext4_xattr_cmp()
1631 *
1632 * Compare two extended attribute blocks for equality.
1633 *
1634 * Returns 0 if the blocks are equal, 1 if they differ, and
1635 * a negative error number on errors.
1636 */
1637static int
1638ext4_xattr_cmp(struct ext4_xattr_header *header1,
1639	       struct ext4_xattr_header *header2)
1640{
1641	struct ext4_xattr_entry *entry1, *entry2;
1642
1643	entry1 = ENTRY(header1+1);
1644	entry2 = ENTRY(header2+1);
1645	while (!IS_LAST_ENTRY(entry1)) {
1646		if (IS_LAST_ENTRY(entry2))
1647			return 1;
1648		if (entry1->e_hash != entry2->e_hash ||
1649		    entry1->e_name_index != entry2->e_name_index ||
1650		    entry1->e_name_len != entry2->e_name_len ||
1651		    entry1->e_value_size != entry2->e_value_size ||
1652		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1653			return 1;
1654		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1655			return -EFSCORRUPTED;
1656		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1657			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1658			   le32_to_cpu(entry1->e_value_size)))
1659			return 1;
1660
1661		entry1 = EXT4_XATTR_NEXT(entry1);
1662		entry2 = EXT4_XATTR_NEXT(entry2);
1663	}
1664	if (!IS_LAST_ENTRY(entry2))
1665		return 1;
1666	return 0;
1667}
1668
1669/*
1670 * ext4_xattr_cache_find()
1671 *
1672 * Find an identical extended attribute block.
1673 *
1674 * Returns a pointer to the block found, or NULL if such a block was
1675 * not found or an error occurred.
1676 */
1677static struct buffer_head *
1678ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1679		      struct mb_cache_entry **pce)
1680{
1681	__u32 hash = le32_to_cpu(header->h_hash);
1682	struct mb_cache_entry *ce;
1683	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1684
1685	if (!header->h_hash)
1686		return NULL;  /* never share */
1687	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1688	ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1689	while (ce) {
1690		struct buffer_head *bh;
1691
1692		bh = sb_bread(inode->i_sb, ce->e_block);
1693		if (!bh) {
1694			EXT4_ERROR_INODE(inode, "block %lu read error",
1695					 (unsigned long) ce->e_block);
1696		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1697			*pce = ce;
1698			return bh;
1699		}
1700		brelse(bh);
1701		ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1702	}
1703	return NULL;
1704}
1705
1706#define NAME_HASH_SHIFT 5
1707#define VALUE_HASH_SHIFT 16
1708
1709/*
1710 * ext4_xattr_hash_entry()
1711 *
1712 * Compute the hash of an extended attribute.
1713 */
1714static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1715					 struct ext4_xattr_entry *entry)
1716{
1717	__u32 hash = 0;
1718	char *name = entry->e_name;
1719	int n;
1720
1721	for (n = 0; n < entry->e_name_len; n++) {
1722		hash = (hash << NAME_HASH_SHIFT) ^
1723		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1724		       *name++;
1725	}
1726
1727	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1728		__le32 *value = (__le32 *)((char *)header +
1729			le16_to_cpu(entry->e_value_offs));
1730		for (n = (le32_to_cpu(entry->e_value_size) +
1731		     EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1732			hash = (hash << VALUE_HASH_SHIFT) ^
1733			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1734			       le32_to_cpu(*value++);
1735		}
1736	}
1737	entry->e_hash = cpu_to_le32(hash);
1738}
1739
1740#undef NAME_HASH_SHIFT
1741#undef VALUE_HASH_SHIFT
1742
1743#define BLOCK_HASH_SHIFT 16
1744
1745/*
1746 * ext4_xattr_rehash()
1747 *
1748 * Re-compute the extended attribute hash value after an entry has changed.
1749 */
1750static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1751			      struct ext4_xattr_entry *entry)
1752{
1753	struct ext4_xattr_entry *here;
1754	__u32 hash = 0;
1755
1756	ext4_xattr_hash_entry(header, entry);
1757	here = ENTRY(header+1);
1758	while (!IS_LAST_ENTRY(here)) {
1759		if (!here->e_hash) {
1760			/* Block is not shared if an entry's hash value == 0 */
1761			hash = 0;
1762			break;
1763		}
1764		hash = (hash << BLOCK_HASH_SHIFT) ^
1765		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1766		       le32_to_cpu(here->e_hash);
1767		here = EXT4_XATTR_NEXT(here);
1768	}
1769	header->h_hash = cpu_to_le32(hash);
1770}
1771
1772#undef BLOCK_HASH_SHIFT
1773
1774#define	HASH_BUCKET_BITS	10
1775
1776struct mb_cache *
1777ext4_xattr_create_cache(void)
1778{
1779	return mb_cache_create(HASH_BUCKET_BITS);
1780}
1781
1782void ext4_xattr_destroy_cache(struct mb_cache *cache)
1783{
1784	if (cache)
1785		mb_cache_destroy(cache);
1786}
1787