xattr.c 41.4 KB
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/*
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 * linux/fs/ext4/xattr.c
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 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 *
 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
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 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
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 * Extended attributes for symlinks and special files added per
 *  suggestion of Luka Renko <luka.renko@hermes.si>.
 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
 *  Red Hat Inc.
 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
 *  and Andreas Gruenbacher <agruen@suse.de>.
 */

/*
 * Extended attributes are stored directly in inodes (on file systems with
 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
 * field contains the block number if an inode uses an additional block. All
 * attributes must fit in the inode and one additional block. Blocks that
 * contain the identical set of attributes may be shared among several inodes.
 * Identical blocks are detected by keeping a cache of blocks that have
 * recently been accessed.
 *
 * The attributes in inodes and on blocks have a different header; the entries
 * are stored in the same format:
 *
 *   +------------------+
 *   | header           |
 *   | entry 1          | |
 *   | entry 2          | | growing downwards
 *   | entry 3          | v
 *   | four null bytes  |
 *   | . . .            |
 *   | value 1          | ^
 *   | value 3          | | growing upwards
 *   | value 2          | |
 *   +------------------+
 *
 * The header is followed by multiple entry descriptors. In disk blocks, the
 * entry descriptors are kept sorted. In inodes, they are unsorted. The
 * attribute values are aligned to the end of the block in no specific order.
 *
 * Locking strategy
 * ----------------
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 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
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 * EA blocks are only changed if they are exclusive to an inode, so
 * holding xattr_sem also means that nothing but the EA block's reference
 * count can change. Multiple writers to the same block are synchronized
 * by the buffer lock.
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/mbcache.h>
#include <linux/quotaops.h>
#include <linux/rwsem.h>
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#include "ext4_jbd2.h"
#include "ext4.h"
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#include "xattr.h"
#include "acl.h"

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#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
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#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)

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#ifdef EXT4_XATTR_DEBUG
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# define ea_idebug(inode, f...) do { \
		printk(KERN_DEBUG "inode %s:%lu: ", \
			inode->i_sb->s_id, inode->i_ino); \
		printk(f); \
		printk("\n"); \
	} while (0)
# define ea_bdebug(bh, f...) do { \
		char b[BDEVNAME_SIZE]; \
		printk(KERN_DEBUG "block %s:%lu: ", \
			bdevname(bh->b_bdev, b), \
			(unsigned long) bh->b_blocknr); \
		printk(f); \
		printk("\n"); \
	} while (0)
#else
# define ea_idebug(f...)
# define ea_bdebug(f...)
#endif

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static void ext4_xattr_cache_insert(struct buffer_head *);
static struct buffer_head *ext4_xattr_cache_find(struct inode *,
						 struct ext4_xattr_header *,
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						 struct mb_cache_entry **);
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static void ext4_xattr_rehash(struct ext4_xattr_header *,
			      struct ext4_xattr_entry *);
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static int ext4_xattr_list(struct inode *inode, char *buffer,
			   size_t buffer_size);
97

98
static struct mb_cache *ext4_xattr_cache;
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static struct xattr_handler *ext4_xattr_handler_map[] = {
	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
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#endif
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	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4DEV_FS_SECURITY
	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
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#endif
};

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struct xattr_handler *ext4_xattr_handlers[] = {
	&ext4_xattr_user_handler,
	&ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
	&ext4_xattr_acl_access_handler,
	&ext4_xattr_acl_default_handler,
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#endif
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#ifdef CONFIG_EXT4DEV_FS_SECURITY
	&ext4_xattr_security_handler,
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#endif
	NULL
};

static inline struct xattr_handler *
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ext4_xattr_handler(int name_index)
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{
	struct xattr_handler *handler = NULL;

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	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
		handler = ext4_xattr_handler_map[name_index];
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	return handler;
}

/*
 * Inode operation listxattr()
 *
 * dentry->d_inode->i_mutex: don't care
 */
ssize_t
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ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142
{
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	return ext4_xattr_list(dentry->d_inode, buffer, size);
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}

static int
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ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
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{
	while (!IS_LAST_ENTRY(entry)) {
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		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
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		if ((void *)next >= end)
			return -EIO;
		entry = next;
	}
	return 0;
}

static inline int
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ext4_xattr_check_block(struct buffer_head *bh)
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{
	int error;

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	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
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	    BHDR(bh)->h_blocks != cpu_to_le32(1))
		return -EIO;
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	error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
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	return error;
}

static inline int
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ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
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{
	size_t value_size = le32_to_cpu(entry->e_value_size);

	if (entry->e_value_block != 0 || value_size > size ||
	    le16_to_cpu(entry->e_value_offs) + value_size > size)
		return -EIO;
	return 0;
}

static int
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ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
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		      const char *name, size_t size, int sorted)
{
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	struct ext4_xattr_entry *entry;
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	size_t name_len;
	int cmp = 1;

	if (name == NULL)
		return -EINVAL;
	name_len = strlen(name);
	entry = *pentry;
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	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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		cmp = name_index - entry->e_name_index;
		if (!cmp)
			cmp = name_len - entry->e_name_len;
		if (!cmp)
			cmp = memcmp(name, entry->e_name, name_len);
		if (cmp <= 0 && (sorted || cmp == 0))
			break;
	}
	*pentry = entry;
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	if (!cmp && ext4_xattr_check_entry(entry, size))
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			return -EIO;
	return cmp ? -ENODATA : 0;
}

static int
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ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
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		     void *buffer, size_t buffer_size)
{
	struct buffer_head *bh = NULL;
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	struct ext4_xattr_entry *entry;
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	size_t size;
	int error;

	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
		  name_index, name, buffer, (long)buffer_size);

	error = -ENODATA;
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	if (!EXT4_I(inode)->i_file_acl)
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		goto cleanup;
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	ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
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	if (!bh)
		goto cleanup;
	ea_bdebug(bh, "b_count=%d, refcount=%d",
		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
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	if (ext4_xattr_check_block(bh)) {
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bad_block:	ext4_error(inode->i_sb, __func__,
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			   "inode %lu: bad block %llu", inode->i_ino,
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			   EXT4_I(inode)->i_file_acl);
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		error = -EIO;
		goto cleanup;
	}
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	ext4_xattr_cache_insert(bh);
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	entry = BFIRST(bh);
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	error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
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	if (error == -EIO)
		goto bad_block;
	if (error)
		goto cleanup;
	size = le32_to_cpu(entry->e_value_size);
	if (buffer) {
		error = -ERANGE;
		if (size > buffer_size)
			goto cleanup;
		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
		       size);
	}
	error = size;

cleanup:
	brelse(bh);
	return error;
}

static int
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ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
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		     void *buffer, size_t buffer_size)
{
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	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_entry *entry;
	struct ext4_inode *raw_inode;
	struct ext4_iloc iloc;
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	size_t size;
	void *end;
	int error;

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	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
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		return -ENODATA;
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	error = ext4_get_inode_loc(inode, &iloc);
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	if (error)
		return error;
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	raw_inode = ext4_raw_inode(&iloc);
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	header = IHDR(inode, raw_inode);
	entry = IFIRST(header);
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	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	error = ext4_xattr_check_names(entry, end);
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	if (error)
		goto cleanup;
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	error = ext4_xattr_find_entry(&entry, name_index, name,
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				      end - (void *)entry, 0);
	if (error)
		goto cleanup;
	size = le32_to_cpu(entry->e_value_size);
	if (buffer) {
		error = -ERANGE;
		if (size > buffer_size)
			goto cleanup;
		memcpy(buffer, (void *)IFIRST(header) +
		       le16_to_cpu(entry->e_value_offs), size);
	}
	error = size;

cleanup:
	brelse(iloc.bh);
	return error;
}

/*
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 * ext4_xattr_get()
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 *
 * Copy an extended attribute into the buffer
 * provided, or compute the buffer size required.
 * Buffer is NULL to compute the size of the buffer required.
 *
 * Returns a negative error number on failure, or the number of bytes
 * used / required on success.
 */
int
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ext4_xattr_get(struct inode *inode, int name_index, const char *name,
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	       void *buffer, size_t buffer_size)
{
	int error;

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	down_read(&EXT4_I(inode)->xattr_sem);
	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
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				     buffer_size);
	if (error == -ENODATA)
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		error = ext4_xattr_block_get(inode, name_index, name, buffer,
322
					     buffer_size);
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	up_read(&EXT4_I(inode)->xattr_sem);
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	return error;
}

static int
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ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
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			char *buffer, size_t buffer_size)
{
	size_t rest = buffer_size;

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	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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		struct xattr_handler *handler =
335
			ext4_xattr_handler(entry->e_name_index);
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		if (handler) {
			size_t size = handler->list(inode, buffer, rest,
						    entry->e_name,
						    entry->e_name_len);
			if (buffer) {
				if (size > rest)
					return -ERANGE;
				buffer += size;
			}
			rest -= size;
		}
	}
	return buffer_size - rest;
}

static int
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ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
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{
	struct buffer_head *bh = NULL;
	int error;

	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
		  buffer, (long)buffer_size);

	error = 0;
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	if (!EXT4_I(inode)->i_file_acl)
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		goto cleanup;
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	ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
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	error = -EIO;
	if (!bh)
		goto cleanup;
	ea_bdebug(bh, "b_count=%d, refcount=%d",
		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
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	if (ext4_xattr_check_block(bh)) {
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		ext4_error(inode->i_sb, __func__,
373
			   "inode %lu: bad block %llu", inode->i_ino,
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			   EXT4_I(inode)->i_file_acl);
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		error = -EIO;
		goto cleanup;
	}
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	ext4_xattr_cache_insert(bh);
	error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
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cleanup:
	brelse(bh);

	return error;
}

static int
388
ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
389
{
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	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
	struct ext4_iloc iloc;
393 394 395
	void *end;
	int error;

396
	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
397
		return 0;
398
	error = ext4_get_inode_loc(inode, &iloc);
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	if (error)
		return error;
401
	raw_inode = ext4_raw_inode(&iloc);
402
	header = IHDR(inode, raw_inode);
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	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	error = ext4_xattr_check_names(IFIRST(header), end);
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	if (error)
		goto cleanup;
407
	error = ext4_xattr_list_entries(inode, IFIRST(header),
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					buffer, buffer_size);

cleanup:
	brelse(iloc.bh);
	return error;
}

/*
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 * ext4_xattr_list()
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 *
 * Copy a list of attribute names into the buffer
 * provided, or compute the buffer size required.
 * Buffer is NULL to compute the size of the buffer required.
 *
 * Returns a negative error number on failure, or the number of bytes
 * used / required on success.
 */
425
static int
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ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
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{
	int i_error, b_error;

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	down_read(&EXT4_I(inode)->xattr_sem);
	i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
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	if (i_error < 0) {
		b_error = 0;
	} else {
		if (buffer) {
			buffer += i_error;
			buffer_size -= i_error;
		}
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		b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
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		if (b_error < 0)
			i_error = 0;
	}
443
	up_read(&EXT4_I(inode)->xattr_sem);
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	return i_error + b_error;
}

/*
448
 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
449 450
 * not set, set it.
 */
451
static void ext4_xattr_update_super_block(handle_t *handle,
452 453
					  struct super_block *sb)
{
454
	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
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		return;

457
	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
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		EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
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		sb->s_dirt = 1;
460
		ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
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	}
}

/*
 * Release the xattr block BH: If the reference count is > 1, decrement
 * it; otherwise free the block.
 */
static void
469
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
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			 struct buffer_head *bh)
{
	struct mb_cache_entry *ce = NULL;
473
	int error = 0;
474

475
	ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
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	error = ext4_journal_get_write_access(handle, bh);
	if (error)
		goto out;

	lock_buffer(bh);
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	if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
		ea_bdebug(bh, "refcount now=0; freeing");
		if (ce)
			mb_cache_entry_free(ce);
485
		ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1);
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		get_bh(bh);
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		ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
488
	} else {
M
Marcin Slusarz 已提交
489
		le32_add_cpu(&BHDR(bh)->h_refcount, -1);
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		error = ext4_journal_dirty_metadata(handle, bh);
		if (IS_SYNC(inode))
			handle->h_sync = 1;
		DQUOT_FREE_BLOCK(inode, 1);
		ea_bdebug(bh, "refcount now=%d; releasing",
			  le32_to_cpu(BHDR(bh)->h_refcount));
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		if (ce)
			mb_cache_entry_release(ce);
	}
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	unlock_buffer(bh);
out:
	ext4_std_error(inode->i_sb, error);
	return;
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}

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/*
 * Find the available free space for EAs. This also returns the total number of
 * bytes used by EA entries.
 */
static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
				    size_t *min_offs, void *base, int *total)
{
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
		*total += EXT4_XATTR_LEN(last->e_name_len);
		if (!last->e_value_block && last->e_value_size) {
			size_t offs = le16_to_cpu(last->e_value_offs);
			if (offs < *min_offs)
				*min_offs = offs;
		}
	}
	return (*min_offs - ((void *)last - base) - sizeof(__u32));
}

523
struct ext4_xattr_info {
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	int name_index;
	const char *name;
	const void *value;
	size_t value_len;
};

530 531
struct ext4_xattr_search {
	struct ext4_xattr_entry *first;
532 533
	void *base;
	void *end;
534
	struct ext4_xattr_entry *here;
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	int not_found;
};

static int
539
ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
540
{
541
	struct ext4_xattr_entry *last;
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	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);

	/* Compute min_offs and last. */
	last = s->first;
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	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
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		if (!last->e_value_block && last->e_value_size) {
			size_t offs = le16_to_cpu(last->e_value_offs);
			if (offs < min_offs)
				min_offs = offs;
		}
	}
	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
	if (!s->not_found) {
		if (!s->here->e_value_block && s->here->e_value_size) {
			size_t size = le32_to_cpu(s->here->e_value_size);
557
			free += EXT4_XATTR_SIZE(size);
558
		}
559
		free += EXT4_XATTR_LEN(name_len);
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	}
	if (i->value) {
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		if (free < EXT4_XATTR_SIZE(i->value_len) ||
		    free < EXT4_XATTR_LEN(name_len) +
			   EXT4_XATTR_SIZE(i->value_len))
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			return -ENOSPC;
	}

	if (i->value && s->not_found) {
		/* Insert the new name. */
570
		size_t size = EXT4_XATTR_LEN(name_len);
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		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
		memmove((void *)s->here + size, s->here, rest);
		memset(s->here, 0, size);
		s->here->e_name_index = i->name_index;
		s->here->e_name_len = name_len;
		memcpy(s->here->e_name, i->name, name_len);
	} else {
		if (!s->here->e_value_block && s->here->e_value_size) {
			void *first_val = s->base + min_offs;
			size_t offs = le16_to_cpu(s->here->e_value_offs);
			void *val = s->base + offs;
582
			size_t size = EXT4_XATTR_SIZE(
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				le32_to_cpu(s->here->e_value_size));

585
			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
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				/* The old and the new value have the same
				   size. Just replace. */
				s->here->e_value_size =
					cpu_to_le32(i->value_len);
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				memset(val + size - EXT4_XATTR_PAD, 0,
				       EXT4_XATTR_PAD); /* Clear pad bytes. */
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				memcpy(val, i->value, i->value_len);
				return 0;
			}

			/* Remove the old value. */
			memmove(first_val + size, first_val, val - first_val);
			memset(first_val, 0, size);
			s->here->e_value_size = 0;
			s->here->e_value_offs = 0;
			min_offs += size;

			/* Adjust all value offsets. */
			last = s->first;
			while (!IS_LAST_ENTRY(last)) {
				size_t o = le16_to_cpu(last->e_value_offs);
				if (!last->e_value_block &&
				    last->e_value_size && o < offs)
					last->e_value_offs =
						cpu_to_le16(o + size);
611
				last = EXT4_XATTR_NEXT(last);
612 613 614 615
			}
		}
		if (!i->value) {
			/* Remove the old name. */
616
			size_t size = EXT4_XATTR_LEN(name_len);
617 618 619 620 621 622 623 624 625 626 627
			last = ENTRY((void *)last - size);
			memmove(s->here, (void *)s->here + size,
				(void *)last - (void *)s->here + sizeof(__u32));
			memset(last, 0, size);
		}
	}

	if (i->value) {
		/* Insert the new value. */
		s->here->e_value_size = cpu_to_le32(i->value_len);
		if (i->value_len) {
628
			size_t size = EXT4_XATTR_SIZE(i->value_len);
629 630
			void *val = s->base + min_offs - size;
			s->here->e_value_offs = cpu_to_le16(min_offs - size);
631 632
			memset(val + size - EXT4_XATTR_PAD, 0,
			       EXT4_XATTR_PAD); /* Clear the pad bytes. */
633 634 635 636 637 638
			memcpy(val, i->value, i->value_len);
		}
	}
	return 0;
}

639 640
struct ext4_xattr_block_find {
	struct ext4_xattr_search s;
641 642 643 644
	struct buffer_head *bh;
};

static int
645 646
ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
		      struct ext4_xattr_block_find *bs)
647 648 649 650 651 652 653
{
	struct super_block *sb = inode->i_sb;
	int error;

	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
		  i->name_index, i->name, i->value, (long)i->value_len);

654
	if (EXT4_I(inode)->i_file_acl) {
655
		/* The inode already has an extended attribute block. */
656
		bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
657 658 659 660 661 662
		error = -EIO;
		if (!bs->bh)
			goto cleanup;
		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
			atomic_read(&(bs->bh->b_count)),
			le32_to_cpu(BHDR(bs->bh)->h_refcount));
663
		if (ext4_xattr_check_block(bs->bh)) {
664
			ext4_error(sb, __func__,
665
				"inode %lu: bad block %llu", inode->i_ino,
666
				EXT4_I(inode)->i_file_acl);
667 668 669 670 671 672 673 674
			error = -EIO;
			goto cleanup;
		}
		/* Find the named attribute. */
		bs->s.base = BHDR(bs->bh);
		bs->s.first = BFIRST(bs->bh);
		bs->s.end = bs->bh->b_data + bs->bh->b_size;
		bs->s.here = bs->s.first;
675
		error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
676 677 678 679 680 681 682 683 684 685 686 687
					      i->name, bs->bh->b_size, 1);
		if (error && error != -ENODATA)
			goto cleanup;
		bs->s.not_found = error;
	}
	error = 0;

cleanup:
	return error;
}

static int
688 689 690
ext4_xattr_block_set(handle_t *handle, struct inode *inode,
		     struct ext4_xattr_info *i,
		     struct ext4_xattr_block_find *bs)
691 692 693
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *new_bh = NULL;
694
	struct ext4_xattr_search *s = &bs->s;
695
	struct mb_cache_entry *ce = NULL;
696
	int error = 0;
697

698
#define header(x) ((struct ext4_xattr_header *)(x))
699 700 701 702

	if (i->value && i->value_len > sb->s_blocksize)
		return -ENOSPC;
	if (s->base) {
703
		ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
704
					bs->bh->b_blocknr);
705 706 707 708 709
		error = ext4_journal_get_write_access(handle, bs->bh);
		if (error)
			goto cleanup;
		lock_buffer(bs->bh);

710 711 712 713 714 715
		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
			if (ce) {
				mb_cache_entry_free(ce);
				ce = NULL;
			}
			ea_bdebug(bs->bh, "modifying in-place");
716
			error = ext4_xattr_set_entry(i, s);
717 718
			if (!error) {
				if (!IS_LAST_ENTRY(s->first))
719
					ext4_xattr_rehash(header(s->base),
720
							  s->here);
721
				ext4_xattr_cache_insert(bs->bh);
722 723 724 725 726
			}
			unlock_buffer(bs->bh);
			if (error == -EIO)
				goto bad_block;
			if (!error)
727
				error = ext4_journal_dirty_metadata(handle,
728 729 730 731 732 733 734
								    bs->bh);
			if (error)
				goto cleanup;
			goto inserted;
		} else {
			int offset = (char *)s->here - bs->bh->b_data;

735 736
			unlock_buffer(bs->bh);
			jbd2_journal_release_buffer(handle, bs->bh);
737 738 739 740 741
			if (ce) {
				mb_cache_entry_release(ce);
				ce = NULL;
			}
			ea_bdebug(bs->bh, "cloning");
742
			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
743 744 745 746 747 748 749 750 751 752 753
			error = -ENOMEM;
			if (s->base == NULL)
				goto cleanup;
			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
			s->first = ENTRY(header(s->base)+1);
			header(s->base)->h_refcount = cpu_to_le32(1);
			s->here = ENTRY(s->base + offset);
			s->end = s->base + bs->bh->b_size;
		}
	} else {
		/* Allocate a buffer where we construct the new block. */
754
		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
755 756 757 758
		/* assert(header == s->base) */
		error = -ENOMEM;
		if (s->base == NULL)
			goto cleanup;
759
		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
760 761 762 763 764 765 766
		header(s->base)->h_blocks = cpu_to_le32(1);
		header(s->base)->h_refcount = cpu_to_le32(1);
		s->first = ENTRY(header(s->base)+1);
		s->here = ENTRY(header(s->base)+1);
		s->end = s->base + sb->s_blocksize;
	}

767
	error = ext4_xattr_set_entry(i, s);
768 769 770 771 772
	if (error == -EIO)
		goto bad_block;
	if (error)
		goto cleanup;
	if (!IS_LAST_ENTRY(s->first))
773
		ext4_xattr_rehash(header(s->base), s->here);
774 775 776

inserted:
	if (!IS_LAST_ENTRY(s->first)) {
777
		new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
778 779 780 781 782 783 784 785 786 787
		if (new_bh) {
			/* We found an identical block in the cache. */
			if (new_bh == bs->bh)
				ea_bdebug(new_bh, "keeping");
			else {
				/* The old block is released after updating
				   the inode. */
				error = -EDQUOT;
				if (DQUOT_ALLOC_BLOCK(inode, 1))
					goto cleanup;
788
				error = ext4_journal_get_write_access(handle,
789 790 791 792
								      new_bh);
				if (error)
					goto cleanup_dquot;
				lock_buffer(new_bh);
M
Marcin Slusarz 已提交
793
				le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
794 795 796
				ea_bdebug(new_bh, "reusing; refcount now=%d",
					le32_to_cpu(BHDR(new_bh)->h_refcount));
				unlock_buffer(new_bh);
797
				error = ext4_journal_dirty_metadata(handle,
798 799 800 801 802 803 804 805 806 807 808 809 810
								    new_bh);
				if (error)
					goto cleanup_dquot;
			}
			mb_cache_entry_release(ce);
			ce = NULL;
		} else if (bs->bh && s->base == bs->bh->b_data) {
			/* We were modifying this block in-place. */
			ea_bdebug(bs->bh, "keeping this block");
			new_bh = bs->bh;
			get_bh(new_bh);
		} else {
			/* We need to allocate a new block */
811 812
			ext4_fsblk_t goal = ext4_group_first_block_no(sb,
						EXT4_I(inode)->i_block_group);
813
			ext4_fsblk_t block = ext4_new_meta_block(handle, inode,
814 815 816 817 818 819 820 821
							goal, &error);
			if (error)
				goto cleanup;
			ea_idebug(inode, "creating block %d", block);

			new_bh = sb_getblk(sb, block);
			if (!new_bh) {
getblk_failed:
822
				ext4_free_blocks(handle, inode, block, 1, 1);
823 824 825 826
				error = -EIO;
				goto cleanup;
			}
			lock_buffer(new_bh);
827
			error = ext4_journal_get_create_access(handle, new_bh);
828 829 830 831 832 833 834
			if (error) {
				unlock_buffer(new_bh);
				goto getblk_failed;
			}
			memcpy(new_bh->b_data, s->base, new_bh->b_size);
			set_buffer_uptodate(new_bh);
			unlock_buffer(new_bh);
835 836
			ext4_xattr_cache_insert(new_bh);
			error = ext4_journal_dirty_metadata(handle, new_bh);
837 838 839 840 841 842
			if (error)
				goto cleanup;
		}
	}

	/* Update the inode. */
843
	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
844 845 846

	/* Drop the previous xattr block. */
	if (bs->bh && bs->bh != new_bh)
847
		ext4_xattr_release_block(handle, inode, bs->bh);
848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
	error = 0;

cleanup:
	if (ce)
		mb_cache_entry_release(ce);
	brelse(new_bh);
	if (!(bs->bh && s->base == bs->bh->b_data))
		kfree(s->base);

	return error;

cleanup_dquot:
	DQUOT_FREE_BLOCK(inode, 1);
	goto cleanup;

bad_block:
864
	ext4_error(inode->i_sb, __func__,
865
		   "inode %lu: bad block %llu", inode->i_ino,
866
		   EXT4_I(inode)->i_file_acl);
867 868 869 870 871
	goto cleanup;

#undef header
}

872 873 874
struct ext4_xattr_ibody_find {
	struct ext4_xattr_search s;
	struct ext4_iloc iloc;
875 876 877
};

static int
878 879
ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
		      struct ext4_xattr_ibody_find *is)
880
{
881 882
	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
883 884
	int error;

885
	if (EXT4_I(inode)->i_extra_isize == 0)
886
		return 0;
887
	raw_inode = ext4_raw_inode(&is->iloc);
888 889 890
	header = IHDR(inode, raw_inode);
	is->s.base = is->s.first = IFIRST(header);
	is->s.here = is->s.first;
891 892 893
	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
		error = ext4_xattr_check_names(IFIRST(header), is->s.end);
894 895 896
		if (error)
			return error;
		/* Find the named attribute. */
897
		error = ext4_xattr_find_entry(&is->s.here, i->name_index,
898 899 900 901 902 903 904 905 906 907
					      i->name, is->s.end -
					      (void *)is->s.base, 0);
		if (error && error != -ENODATA)
			return error;
		is->s.not_found = error;
	}
	return 0;
}

static int
908 909 910
ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
		     struct ext4_xattr_info *i,
		     struct ext4_xattr_ibody_find *is)
911
{
912 913
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_search *s = &is->s;
914 915
	int error;

916
	if (EXT4_I(inode)->i_extra_isize == 0)
917
		return -ENOSPC;
918
	error = ext4_xattr_set_entry(i, s);
919 920
	if (error)
		return error;
921
	header = IHDR(inode, ext4_raw_inode(&is->iloc));
922
	if (!IS_LAST_ENTRY(s->first)) {
923 924
		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
		EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
925 926
	} else {
		header->h_magic = cpu_to_le32(0);
927
		EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
928 929 930 931 932
	}
	return 0;
}

/*
933
 * ext4_xattr_set_handle()
934 935 936 937 938 939 940 941 942 943 944
 *
 * Create, replace or remove an extended attribute for this inode. Buffer
 * is NULL to remove an existing extended attribute, and non-NULL to
 * either replace an existing extended attribute, or create a new extended
 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 * specify that an extended attribute must exist and must not exist
 * previous to the call, respectively.
 *
 * Returns 0, or a negative error number on failure.
 */
int
945
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
946 947 948
		      const char *name, const void *value, size_t value_len,
		      int flags)
{
949
	struct ext4_xattr_info i = {
950 951 952 953 954 955
		.name_index = name_index,
		.name = name,
		.value = value,
		.value_len = value_len,

	};
956
	struct ext4_xattr_ibody_find is = {
957 958
		.s = { .not_found = -ENODATA, },
	};
959
	struct ext4_xattr_block_find bs = {
960 961 962 963 964 965 966 967
		.s = { .not_found = -ENODATA, },
	};
	int error;

	if (!name)
		return -EINVAL;
	if (strlen(name) > 255)
		return -ERANGE;
968 969
	down_write(&EXT4_I(inode)->xattr_sem);
	error = ext4_get_inode_loc(inode, &is.iloc);
970 971 972
	if (error)
		goto cleanup;

973 974 975 976
	if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
		EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
977 978
	}

979
	error = ext4_xattr_ibody_find(inode, &i, &is);
980 981 982
	if (error)
		goto cleanup;
	if (is.s.not_found)
983
		error = ext4_xattr_block_find(inode, &i, &bs);
984 985 986 987 988 989 990 991 992 993 994 995 996 997
	if (error)
		goto cleanup;
	if (is.s.not_found && bs.s.not_found) {
		error = -ENODATA;
		if (flags & XATTR_REPLACE)
			goto cleanup;
		error = 0;
		if (!value)
			goto cleanup;
	} else {
		error = -EEXIST;
		if (flags & XATTR_CREATE)
			goto cleanup;
	}
998
	error = ext4_journal_get_write_access(handle, is.iloc.bh);
999 1000 1001 1002
	if (error)
		goto cleanup;
	if (!value) {
		if (!is.s.not_found)
1003
			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1004
		else if (!bs.s.not_found)
1005
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1006
	} else {
1007
		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1008 1009
		if (!error && !bs.s.not_found) {
			i.value = NULL;
1010
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1011
		} else if (error == -ENOSPC) {
1012 1013 1014 1015 1016
			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
				error = ext4_xattr_block_find(inode, &i, &bs);
				if (error)
					goto cleanup;
			}
1017
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1018 1019 1020 1021
			if (error)
				goto cleanup;
			if (!is.s.not_found) {
				i.value = NULL;
1022
				error = ext4_xattr_ibody_set(handle, inode, &i,
1023 1024 1025 1026 1027
							     &is);
			}
		}
	}
	if (!error) {
1028
		ext4_xattr_update_super_block(handle, inode->i_sb);
K
Kalpak Shah 已提交
1029
		inode->i_ctime = ext4_current_time(inode);
1030 1031
		if (!value)
			EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1032
		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1033
		/*
1034
		 * The bh is consumed by ext4_mark_iloc_dirty, even with
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
		 * error != 0.
		 */
		is.iloc.bh = NULL;
		if (IS_SYNC(inode))
			handle->h_sync = 1;
	}

cleanup:
	brelse(is.iloc.bh);
	brelse(bs.bh);
1045
	up_write(&EXT4_I(inode)->xattr_sem);
1046 1047 1048 1049
	return error;
}

/*
1050
 * ext4_xattr_set()
1051
 *
1052
 * Like ext4_xattr_set_handle, but start from an inode. This extended
1053 1054 1055 1056 1057
 * attribute modification is a filesystem transaction by itself.
 *
 * Returns 0, or a negative error number on failure.
 */
int
1058
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1059 1060 1061 1062 1063 1064
	       const void *value, size_t value_len, int flags)
{
	handle_t *handle;
	int error, retries = 0;

retry:
1065
	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1066 1067 1068 1069 1070
	if (IS_ERR(handle)) {
		error = PTR_ERR(handle);
	} else {
		int error2;

1071
		error = ext4_xattr_set_handle(handle, inode, name_index, name,
1072
					      value, value_len, flags);
1073
		error2 = ext4_journal_stop(handle);
1074
		if (error == -ENOSPC &&
1075
		    ext4_should_retry_alloc(inode->i_sb, &retries))
1076 1077 1078 1079 1080 1081 1082 1083
			goto retry;
		if (error == 0)
			error = error2;
	}

	return error;
}

1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
/*
 * Shift the EA entries in the inode to create space for the increased
 * i_extra_isize.
 */
static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
				     int value_offs_shift, void *to,
				     void *from, size_t n, int blocksize)
{
	struct ext4_xattr_entry *last = entry;
	int new_offs;

	/* Adjust the value offsets of the entries */
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
		if (!last->e_value_block && last->e_value_size) {
			new_offs = le16_to_cpu(last->e_value_offs) +
							value_offs_shift;
			BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
				 > blocksize);
			last->e_value_offs = cpu_to_le16(new_offs);
		}
	}
	/* Shift the entries by n bytes */
	memmove(to, from, n);
}

/*
 * Expand an inode by new_extra_isize bytes when EAs are present.
 * Returns 0 on success or negative error number on failure.
 */
int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
			       struct ext4_inode *raw_inode, handle_t *handle)
{
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_entry *entry, *last, *first;
	struct buffer_head *bh = NULL;
	struct ext4_xattr_ibody_find *is = NULL;
	struct ext4_xattr_block_find *bs = NULL;
	char *buffer = NULL, *b_entry_name = NULL;
	size_t min_offs, free;
	int total_ino, total_blk;
	void *base, *start, *end;
	int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
A
Aneesh Kumar K.V 已提交
1126
	int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171

	down_write(&EXT4_I(inode)->xattr_sem);
retry:
	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
		up_write(&EXT4_I(inode)->xattr_sem);
		return 0;
	}

	header = IHDR(inode, raw_inode);
	entry = IFIRST(header);

	/*
	 * Check if enough free space is available in the inode to shift the
	 * entries ahead by new_extra_isize.
	 */

	base = start = entry;
	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	min_offs = end - base;
	last = entry;
	total_ino = sizeof(struct ext4_xattr_ibody_header);

	free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
	if (free >= new_extra_isize) {
		entry = IFIRST(header);
		ext4_xattr_shift_entries(entry,	EXT4_I(inode)->i_extra_isize
				- new_extra_isize, (void *)raw_inode +
				EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
				(void *)header, total_ino,
				inode->i_sb->s_blocksize);
		EXT4_I(inode)->i_extra_isize = new_extra_isize;
		error = 0;
		goto cleanup;
	}

	/*
	 * Enough free space isn't available in the inode, check if
	 * EA block can hold new_extra_isize bytes.
	 */
	if (EXT4_I(inode)->i_file_acl) {
		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
		error = -EIO;
		if (!bh)
			goto cleanup;
		if (ext4_xattr_check_block(bh)) {
1172
			ext4_error(inode->i_sb, __func__,
1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
				"inode %lu: bad block %llu", inode->i_ino,
				EXT4_I(inode)->i_file_acl);
			error = -EIO;
			goto cleanup;
		}
		base = BHDR(bh);
		first = BFIRST(bh);
		end = bh->b_data + bh->b_size;
		min_offs = end - base;
		free = ext4_xattr_free_space(first, &min_offs, base,
					     &total_blk);
		if (free < new_extra_isize) {
			if (!tried_min_extra_isize && s_min_extra_isize) {
				tried_min_extra_isize++;
				new_extra_isize = s_min_extra_isize;
				brelse(bh);
				goto retry;
			}
			error = -1;
			goto cleanup;
		}
	} else {
		free = inode->i_sb->s_blocksize;
	}

	while (new_extra_isize > 0) {
		size_t offs, size, entry_size;
		struct ext4_xattr_entry *small_entry = NULL;
		struct ext4_xattr_info i = {
			.value = NULL,
			.value_len = 0,
		};
		unsigned int total_size;  /* EA entry size + value size */
		unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
		unsigned int min_total_size = ~0U;

		is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
		bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
		if (!is || !bs) {
			error = -ENOMEM;
			goto cleanup;
		}

		is->s.not_found = -ENODATA;
		bs->s.not_found = -ENODATA;
		is->iloc.bh = NULL;
		bs->bh = NULL;

		last = IFIRST(header);
		/* Find the entry best suited to be pushed into EA block */
		entry = NULL;
		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
			total_size =
			EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
					EXT4_XATTR_LEN(last->e_name_len);
			if (total_size <= free && total_size < min_total_size) {
				if (total_size < new_extra_isize) {
					small_entry = last;
				} else {
					entry = last;
					min_total_size = total_size;
				}
			}
		}

		if (entry == NULL) {
			if (small_entry) {
				entry = small_entry;
			} else {
				if (!tried_min_extra_isize &&
				    s_min_extra_isize) {
					tried_min_extra_isize++;
					new_extra_isize = s_min_extra_isize;
					goto retry;
				}
				error = -1;
				goto cleanup;
			}
		}
		offs = le16_to_cpu(entry->e_value_offs);
		size = le32_to_cpu(entry->e_value_size);
		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
		i.name_index = entry->e_name_index,
		buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
		b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
		if (!buffer || !b_entry_name) {
			error = -ENOMEM;
			goto cleanup;
		}
		/* Save the entry name and the entry value */
		memcpy(buffer, (void *)IFIRST(header) + offs,
		       EXT4_XATTR_SIZE(size));
		memcpy(b_entry_name, entry->e_name, entry->e_name_len);
		b_entry_name[entry->e_name_len] = '\0';
		i.name = b_entry_name;

		error = ext4_get_inode_loc(inode, &is->iloc);
		if (error)
			goto cleanup;

		error = ext4_xattr_ibody_find(inode, &i, is);
		if (error)
			goto cleanup;

		/* Remove the chosen entry from the inode */
		error = ext4_xattr_ibody_set(handle, inode, &i, is);

		entry = IFIRST(header);
		if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
			shift_bytes = new_extra_isize;
		else
			shift_bytes = entry_size + size;
		/* Adjust the offsets and shift the remaining entries ahead */
		ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
			shift_bytes, (void *)raw_inode +
			EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
			(void *)header, total_ino - entry_size,
			inode->i_sb->s_blocksize);

		extra_isize += shift_bytes;
		new_extra_isize -= shift_bytes;
		EXT4_I(inode)->i_extra_isize = extra_isize;

		i.name = b_entry_name;
		i.value = buffer;
A
Aneesh Kumar K.V 已提交
1298
		i.value_len = size;
1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
		error = ext4_xattr_block_find(inode, &i, bs);
		if (error)
			goto cleanup;

		/* Add entry which was removed from the inode into the block */
		error = ext4_xattr_block_set(handle, inode, &i, bs);
		if (error)
			goto cleanup;
		kfree(b_entry_name);
		kfree(buffer);
		brelse(is->iloc.bh);
		kfree(is);
		kfree(bs);
	}
	brelse(bh);
	up_write(&EXT4_I(inode)->xattr_sem);
	return 0;

cleanup:
	kfree(b_entry_name);
	kfree(buffer);
	if (is)
		brelse(is->iloc.bh);
	kfree(is);
	kfree(bs);
	brelse(bh);
	up_write(&EXT4_I(inode)->xattr_sem);
	return error;
}



1331
/*
1332
 * ext4_xattr_delete_inode()
1333 1334 1335 1336 1337 1338
 *
 * Free extended attribute resources associated with this inode. This
 * is called immediately before an inode is freed. We have exclusive
 * access to the inode.
 */
void
1339
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1340 1341 1342
{
	struct buffer_head *bh = NULL;

1343
	if (!EXT4_I(inode)->i_file_acl)
1344
		goto cleanup;
1345
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1346
	if (!bh) {
1347
		ext4_error(inode->i_sb, __func__,
1348
			"inode %lu: block %llu read error", inode->i_ino,
1349
			EXT4_I(inode)->i_file_acl);
1350 1351
		goto cleanup;
	}
1352
	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1353
	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1354
		ext4_error(inode->i_sb, __func__,
1355
			"inode %lu: bad block %llu", inode->i_ino,
1356
			EXT4_I(inode)->i_file_acl);
1357 1358
		goto cleanup;
	}
1359 1360
	ext4_xattr_release_block(handle, inode, bh);
	EXT4_I(inode)->i_file_acl = 0;
1361 1362 1363 1364 1365 1366

cleanup:
	brelse(bh);
}

/*
1367
 * ext4_xattr_put_super()
1368 1369 1370 1371
 *
 * This is called when a file system is unmounted.
 */
void
1372
ext4_xattr_put_super(struct super_block *sb)
1373 1374 1375 1376 1377
{
	mb_cache_shrink(sb->s_bdev);
}

/*
1378
 * ext4_xattr_cache_insert()
1379 1380 1381 1382 1383 1384 1385
 *
 * Create a new entry in the extended attribute cache, and insert
 * it unless such an entry is already in the cache.
 *
 * Returns 0, or a negative error number on failure.
 */
static void
1386
ext4_xattr_cache_insert(struct buffer_head *bh)
1387 1388 1389 1390 1391
{
	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
	struct mb_cache_entry *ce;
	int error;

1392
	ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410
	if (!ce) {
		ea_bdebug(bh, "out of memory");
		return;
	}
	error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
	if (error) {
		mb_cache_entry_free(ce);
		if (error == -EBUSY) {
			ea_bdebug(bh, "already in cache");
			error = 0;
		}
	} else {
		ea_bdebug(bh, "inserting [%x]", (int)hash);
		mb_cache_entry_release(ce);
	}
}

/*
1411
 * ext4_xattr_cmp()
1412 1413 1414 1415 1416 1417 1418
 *
 * Compare two extended attribute blocks for equality.
 *
 * Returns 0 if the blocks are equal, 1 if they differ, and
 * a negative error number on errors.
 */
static int
1419 1420
ext4_xattr_cmp(struct ext4_xattr_header *header1,
	       struct ext4_xattr_header *header2)
1421
{
1422
	struct ext4_xattr_entry *entry1, *entry2;
1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441

	entry1 = ENTRY(header1+1);
	entry2 = ENTRY(header2+1);
	while (!IS_LAST_ENTRY(entry1)) {
		if (IS_LAST_ENTRY(entry2))
			return 1;
		if (entry1->e_hash != entry2->e_hash ||
		    entry1->e_name_index != entry2->e_name_index ||
		    entry1->e_name_len != entry2->e_name_len ||
		    entry1->e_value_size != entry2->e_value_size ||
		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
			return 1;
		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
			return -EIO;
		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
			   le32_to_cpu(entry1->e_value_size)))
			return 1;

1442 1443
		entry1 = EXT4_XATTR_NEXT(entry1);
		entry2 = EXT4_XATTR_NEXT(entry2);
1444 1445 1446 1447 1448 1449 1450
	}
	if (!IS_LAST_ENTRY(entry2))
		return 1;
	return 0;
}

/*
1451
 * ext4_xattr_cache_find()
1452 1453 1454 1455 1456 1457 1458
 *
 * Find an identical extended attribute block.
 *
 * Returns a pointer to the block found, or NULL if such a block was
 * not found or an error occurred.
 */
static struct buffer_head *
1459
ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1460 1461 1462 1463 1464 1465 1466 1467 1468
		      struct mb_cache_entry **pce)
{
	__u32 hash = le32_to_cpu(header->h_hash);
	struct mb_cache_entry *ce;

	if (!header->h_hash)
		return NULL;  /* never share */
	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
again:
1469
	ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480
				       inode->i_sb->s_bdev, hash);
	while (ce) {
		struct buffer_head *bh;

		if (IS_ERR(ce)) {
			if (PTR_ERR(ce) == -EAGAIN)
				goto again;
			break;
		}
		bh = sb_bread(inode->i_sb, ce->e_block);
		if (!bh) {
1481
			ext4_error(inode->i_sb, __func__,
1482 1483 1484
				"inode %lu: block %lu read error",
				inode->i_ino, (unsigned long) ce->e_block);
		} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1485
				EXT4_XATTR_REFCOUNT_MAX) {
1486 1487 1488
			ea_idebug(inode, "block %lu refcount %d>=%d",
				  (unsigned long) ce->e_block,
				  le32_to_cpu(BHDR(bh)->h_refcount),
1489 1490
					  EXT4_XATTR_REFCOUNT_MAX);
		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503
			*pce = ce;
			return bh;
		}
		brelse(bh);
		ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
	}
	return NULL;
}

#define NAME_HASH_SHIFT 5
#define VALUE_HASH_SHIFT 16

/*
1504
 * ext4_xattr_hash_entry()
1505 1506 1507
 *
 * Compute the hash of an extended attribute.
 */
1508 1509
static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
					 struct ext4_xattr_entry *entry)
1510 1511 1512 1513 1514
{
	__u32 hash = 0;
	char *name = entry->e_name;
	int n;

1515
	for (n = 0; n < entry->e_name_len; n++) {
1516 1517 1518 1519 1520 1521 1522 1523 1524
		hash = (hash << NAME_HASH_SHIFT) ^
		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
		       *name++;
	}

	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
		__le32 *value = (__le32 *)((char *)header +
			le16_to_cpu(entry->e_value_offs));
		for (n = (le32_to_cpu(entry->e_value_size) +
1525
		     EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539
			hash = (hash << VALUE_HASH_SHIFT) ^
			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
			       le32_to_cpu(*value++);
		}
	}
	entry->e_hash = cpu_to_le32(hash);
}

#undef NAME_HASH_SHIFT
#undef VALUE_HASH_SHIFT

#define BLOCK_HASH_SHIFT 16

/*
1540
 * ext4_xattr_rehash()
1541 1542 1543
 *
 * Re-compute the extended attribute hash value after an entry has changed.
 */
1544 1545
static void ext4_xattr_rehash(struct ext4_xattr_header *header,
			      struct ext4_xattr_entry *entry)
1546
{
1547
	struct ext4_xattr_entry *here;
1548 1549
	__u32 hash = 0;

1550
	ext4_xattr_hash_entry(header, entry);
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
	here = ENTRY(header+1);
	while (!IS_LAST_ENTRY(here)) {
		if (!here->e_hash) {
			/* Block is not shared if an entry's hash value == 0 */
			hash = 0;
			break;
		}
		hash = (hash << BLOCK_HASH_SHIFT) ^
		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
		       le32_to_cpu(here->e_hash);
1561
		here = EXT4_XATTR_NEXT(here);
1562 1563 1564 1565 1566 1567 1568
	}
	header->h_hash = cpu_to_le32(hash);
}

#undef BLOCK_HASH_SHIFT

int __init
1569
init_ext4_xattr(void)
1570
{
1571
	ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1572 1573
		sizeof(struct mb_cache_entry) +
		sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1574
	if (!ext4_xattr_cache)
1575 1576 1577 1578 1579
		return -ENOMEM;
	return 0;
}

void
1580
exit_ext4_xattr(void)
1581
{
1582 1583 1584
	if (ext4_xattr_cache)
		mb_cache_destroy(ext4_xattr_cache);
	ext4_xattr_cache = NULL;
1585
}