linux/fs/ext4/xattr.c
Christoph Hellwig 431547b3c4 sanitize xattr handler prototypes
Add a flags argument to struct xattr_handler and pass it to all xattr
handler methods.  This allows using the same methods for multiple
handlers, e.g. for the ACL methods which perform exactly the same action
for the access and default ACLs, just using a different underlying
attribute.  With a little more groundwork it'll also allow sharing the
methods for the regular user/trusted/secure handlers in extN, ocfs2 and
jffs2 like it's already done for xfs in this patch.

Also change the inode argument to the handlers to a dentry to allow
using the handlers mechnism for filesystems that require it later,
e.g. cifs.

[with GFS2 bits updated by Steven Whitehouse <swhiteho@redhat.com>]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:49 -05:00

1612 lines
42 KiB
C

/*
* linux/fs/ext4/xattr.c
*
* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
*
* Fix by Harrison Xing <harrison@mountainviewdata.com>.
* Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
* 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
* ----------------
* EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
* 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>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
#include "acl.h"
#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
#ifdef EXT4_XATTR_DEBUG
# 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
static void ext4_xattr_cache_insert(struct buffer_head *);
static struct buffer_head *ext4_xattr_cache_find(struct inode *,
struct ext4_xattr_header *,
struct mb_cache_entry **);
static void ext4_xattr_rehash(struct ext4_xattr_header *,
struct ext4_xattr_entry *);
static int ext4_xattr_list(struct dentry *dentry, char *buffer,
size_t buffer_size);
static struct mb_cache *ext4_xattr_cache;
static struct xattr_handler *ext4_xattr_handler_map[] = {
[EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
#ifdef CONFIG_EXT4_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,
#endif
[EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4_FS_SECURITY
[EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
#endif
};
struct xattr_handler *ext4_xattr_handlers[] = {
&ext4_xattr_user_handler,
&ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4_FS_POSIX_ACL
&ext4_xattr_acl_access_handler,
&ext4_xattr_acl_default_handler,
#endif
#ifdef CONFIG_EXT4_FS_SECURITY
&ext4_xattr_security_handler,
#endif
NULL
};
static inline struct xattr_handler *
ext4_xattr_handler(int name_index)
{
struct xattr_handler *handler = NULL;
if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
handler = ext4_xattr_handler_map[name_index];
return handler;
}
/*
* Inode operation listxattr()
*
* dentry->d_inode->i_mutex: don't care
*/
ssize_t
ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
return ext4_xattr_list(dentry, buffer, size);
}
static int
ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
{
while (!IS_LAST_ENTRY(entry)) {
struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
if ((void *)next >= end)
return -EIO;
entry = next;
}
return 0;
}
static inline int
ext4_xattr_check_block(struct buffer_head *bh)
{
int error;
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
return -EIO;
error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
return error;
}
static inline int
ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
{
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
ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
const char *name, size_t size, int sorted)
{
struct ext4_xattr_entry *entry;
size_t name_len;
int cmp = 1;
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
entry = *pentry;
for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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;
if (!cmp && ext4_xattr_check_entry(entry, size))
return -EIO;
return cmp ? -ENODATA : 0;
}
static int
ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
struct buffer_head *bh = NULL;
struct ext4_xattr_entry *entry;
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;
if (!EXT4_I(inode)->i_file_acl)
goto cleanup;
ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
if (!bh)
goto cleanup;
ea_bdebug(bh, "b_count=%d, refcount=%d",
atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
if (ext4_xattr_check_block(bh)) {
bad_block: ext4_error(inode->i_sb, __func__,
"inode %lu: bad block %llu", inode->i_ino,
EXT4_I(inode)->i_file_acl);
error = -EIO;
goto cleanup;
}
ext4_xattr_cache_insert(bh);
entry = BFIRST(bh);
error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
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
ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
struct ext4_xattr_ibody_header *header;
struct ext4_xattr_entry *entry;
struct ext4_inode *raw_inode;
struct ext4_iloc iloc;
size_t size;
void *end;
int error;
if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
return -ENODATA;
error = ext4_get_inode_loc(inode, &iloc);
if (error)
return error;
raw_inode = ext4_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
entry = IFIRST(header);
end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
error = ext4_xattr_check_names(entry, end);
if (error)
goto cleanup;
error = ext4_xattr_find_entry(&entry, name_index, name,
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;
}
/*
* ext4_xattr_get()
*
* 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
ext4_xattr_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
int error;
down_read(&EXT4_I(inode)->xattr_sem);
error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
buffer_size);
if (error == -ENODATA)
error = ext4_xattr_block_get(inode, name_index, name, buffer,
buffer_size);
up_read(&EXT4_I(inode)->xattr_sem);
return error;
}
static int
ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
char *buffer, size_t buffer_size)
{
size_t rest = buffer_size;
for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
struct xattr_handler *handler =
ext4_xattr_handler(entry->e_name_index);
if (handler) {
size_t size = handler->list(dentry, buffer, rest,
entry->e_name,
entry->e_name_len,
handler->flags);
if (buffer) {
if (size > rest)
return -ERANGE;
buffer += size;
}
rest -= size;
}
}
return buffer_size - rest;
}
static int
ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
struct inode *inode = dentry->d_inode;
struct buffer_head *bh = NULL;
int error;
ea_idebug(inode, "buffer=%p, buffer_size=%ld",
buffer, (long)buffer_size);
error = 0;
if (!EXT4_I(inode)->i_file_acl)
goto cleanup;
ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
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));
if (ext4_xattr_check_block(bh)) {
ext4_error(inode->i_sb, __func__,
"inode %lu: bad block %llu", inode->i_ino,
EXT4_I(inode)->i_file_acl);
error = -EIO;
goto cleanup;
}
ext4_xattr_cache_insert(bh);
error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
cleanup:
brelse(bh);
return error;
}
static int
ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
struct inode *inode = dentry->d_inode;
struct ext4_xattr_ibody_header *header;
struct ext4_inode *raw_inode;
struct ext4_iloc iloc;
void *end;
int error;
if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
return 0;
error = ext4_get_inode_loc(inode, &iloc);
if (error)
return error;
raw_inode = ext4_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
error = ext4_xattr_check_names(IFIRST(header), end);
if (error)
goto cleanup;
error = ext4_xattr_list_entries(dentry, IFIRST(header),
buffer, buffer_size);
cleanup:
brelse(iloc.bh);
return error;
}
/*
* ext4_xattr_list()
*
* 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.
*/
static int
ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
int i_error, b_error;
down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
if (i_error < 0) {
b_error = 0;
} else {
if (buffer) {
buffer += i_error;
buffer_size -= i_error;
}
b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
if (b_error < 0)
i_error = 0;
}
up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
return i_error + b_error;
}
/*
* If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
* not set, set it.
*/
static void ext4_xattr_update_super_block(handle_t *handle,
struct super_block *sb)
{
if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
return;
if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
sb->s_dirt = 1;
ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
}
}
/*
* Release the xattr block BH: If the reference count is > 1, decrement
* it; otherwise free the block.
*/
static void
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
struct mb_cache_entry *ce = NULL;
int error = 0;
ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
error = ext4_journal_get_write_access(handle, bh);
if (error)
goto out;
lock_buffer(bh);
if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
ea_bdebug(bh, "refcount now=0; freeing");
if (ce)
mb_cache_entry_free(ce);
get_bh(bh);
ext4_free_blocks(handle, inode, bh, 0, 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
} else {
le32_add_cpu(&BHDR(bh)->h_refcount, -1);
error = ext4_handle_dirty_metadata(handle, inode, bh);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
vfs_dq_free_block(inode, 1);
ea_bdebug(bh, "refcount now=%d; releasing",
le32_to_cpu(BHDR(bh)->h_refcount));
if (ce)
mb_cache_entry_release(ce);
}
unlock_buffer(bh);
out:
ext4_std_error(inode->i_sb, error);
return;
}
/*
* 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));
}
struct ext4_xattr_info {
int name_index;
const char *name;
const void *value;
size_t value_len;
};
struct ext4_xattr_search {
struct ext4_xattr_entry *first;
void *base;
void *end;
struct ext4_xattr_entry *here;
int not_found;
};
static int
ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
{
struct ext4_xattr_entry *last;
size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
/* Compute min_offs and last. */
last = s->first;
for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
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);
free += EXT4_XATTR_SIZE(size);
}
free += EXT4_XATTR_LEN(name_len);
}
if (i->value) {
if (free < EXT4_XATTR_SIZE(i->value_len) ||
free < EXT4_XATTR_LEN(name_len) +
EXT4_XATTR_SIZE(i->value_len))
return -ENOSPC;
}
if (i->value && s->not_found) {
/* Insert the new name. */
size_t size = EXT4_XATTR_LEN(name_len);
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;
size_t size = EXT4_XATTR_SIZE(
le32_to_cpu(s->here->e_value_size));
if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
/* The old and the new value have the same
size. Just replace. */
s->here->e_value_size =
cpu_to_le32(i->value_len);
memset(val + size - EXT4_XATTR_PAD, 0,
EXT4_XATTR_PAD); /* Clear pad bytes. */
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);
last = EXT4_XATTR_NEXT(last);
}
}
if (!i->value) {
/* Remove the old name. */
size_t size = EXT4_XATTR_LEN(name_len);
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) {
size_t size = EXT4_XATTR_SIZE(i->value_len);
void *val = s->base + min_offs - size;
s->here->e_value_offs = cpu_to_le16(min_offs - size);
memset(val + size - EXT4_XATTR_PAD, 0,
EXT4_XATTR_PAD); /* Clear the pad bytes. */
memcpy(val, i->value, i->value_len);
}
}
return 0;
}
struct ext4_xattr_block_find {
struct ext4_xattr_search s;
struct buffer_head *bh;
};
static int
ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
struct ext4_xattr_block_find *bs)
{
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);
if (EXT4_I(inode)->i_file_acl) {
/* The inode already has an extended attribute block. */
bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
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));
if (ext4_xattr_check_block(bs->bh)) {
ext4_error(sb, __func__,
"inode %lu: bad block %llu", inode->i_ino,
EXT4_I(inode)->i_file_acl);
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;
error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
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
ext4_xattr_block_set(handle_t *handle, struct inode *inode,
struct ext4_xattr_info *i,
struct ext4_xattr_block_find *bs)
{
struct super_block *sb = inode->i_sb;
struct buffer_head *new_bh = NULL;
struct ext4_xattr_search *s = &bs->s;
struct mb_cache_entry *ce = NULL;
int error = 0;
#define header(x) ((struct ext4_xattr_header *)(x))
if (i->value && i->value_len > sb->s_blocksize)
return -ENOSPC;
if (s->base) {
ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
bs->bh->b_blocknr);
error = ext4_journal_get_write_access(handle, bs->bh);
if (error)
goto cleanup;
lock_buffer(bs->bh);
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");
error = ext4_xattr_set_entry(i, s);
if (!error) {
if (!IS_LAST_ENTRY(s->first))
ext4_xattr_rehash(header(s->base),
s->here);
ext4_xattr_cache_insert(bs->bh);
}
unlock_buffer(bs->bh);
if (error == -EIO)
goto bad_block;
if (!error)
error = ext4_handle_dirty_metadata(handle,
inode,
bs->bh);
if (error)
goto cleanup;
goto inserted;
} else {
int offset = (char *)s->here - bs->bh->b_data;
unlock_buffer(bs->bh);
jbd2_journal_release_buffer(handle, bs->bh);
if (ce) {
mb_cache_entry_release(ce);
ce = NULL;
}
ea_bdebug(bs->bh, "cloning");
s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
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. */
s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
/* assert(header == s->base) */
error = -ENOMEM;
if (s->base == NULL)
goto cleanup;
header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
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;
}
error = ext4_xattr_set_entry(i, s);
if (error == -EIO)
goto bad_block;
if (error)
goto cleanup;
if (!IS_LAST_ENTRY(s->first))
ext4_xattr_rehash(header(s->base), s->here);
inserted:
if (!IS_LAST_ENTRY(s->first)) {
new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
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 (vfs_dq_alloc_block(inode, 1))
goto cleanup;
error = ext4_journal_get_write_access(handle,
new_bh);
if (error)
goto cleanup_dquot;
lock_buffer(new_bh);
le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
ea_bdebug(new_bh, "reusing; refcount now=%d",
le32_to_cpu(BHDR(new_bh)->h_refcount));
unlock_buffer(new_bh);
error = ext4_handle_dirty_metadata(handle,
inode,
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 */
ext4_fsblk_t goal, block;
goal = ext4_group_first_block_no(sb,
EXT4_I(inode)->i_block_group);
/* non-extent files can't have physical blocks past 2^32 */
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
block = ext4_new_meta_blocks(handle, inode,
goal, NULL, &error);
if (error)
goto cleanup;
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
ea_idebug(inode, "creating block %d", block);
new_bh = sb_getblk(sb, block);
if (!new_bh) {
getblk_failed:
ext4_free_blocks(handle, inode, 0, block, 1,
EXT4_FREE_BLOCKS_METADATA);
error = -EIO;
goto cleanup;
}
lock_buffer(new_bh);
error = ext4_journal_get_create_access(handle, new_bh);
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);
ext4_xattr_cache_insert(new_bh);
error = ext4_handle_dirty_metadata(handle,
inode, new_bh);
if (error)
goto cleanup;
}
}
/* Update the inode. */
EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
/* Drop the previous xattr block. */
if (bs->bh && bs->bh != new_bh)
ext4_xattr_release_block(handle, inode, bs->bh);
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:
vfs_dq_free_block(inode, 1);
goto cleanup;
bad_block:
ext4_error(inode->i_sb, __func__,
"inode %lu: bad block %llu", inode->i_ino,
EXT4_I(inode)->i_file_acl);
goto cleanup;
#undef header
}
struct ext4_xattr_ibody_find {
struct ext4_xattr_search s;
struct ext4_iloc iloc;
};
static int
ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
struct ext4_xattr_ibody_find *is)
{
struct ext4_xattr_ibody_header *header;
struct ext4_inode *raw_inode;
int error;
if (EXT4_I(inode)->i_extra_isize == 0)
return 0;
raw_inode = ext4_raw_inode(&is->iloc);
header = IHDR(inode, raw_inode);
is->s.base = is->s.first = IFIRST(header);
is->s.here = is->s.first;
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);
if (error)
return error;
/* Find the named attribute. */
error = ext4_xattr_find_entry(&is->s.here, i->name_index,
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
ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
struct ext4_xattr_info *i,
struct ext4_xattr_ibody_find *is)
{
struct ext4_xattr_ibody_header *header;
struct ext4_xattr_search *s = &is->s;
int error;
if (EXT4_I(inode)->i_extra_isize == 0)
return -ENOSPC;
error = ext4_xattr_set_entry(i, s);
if (error)
return error;
header = IHDR(inode, ext4_raw_inode(&is->iloc));
if (!IS_LAST_ENTRY(s->first)) {
header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
} else {
header->h_magic = cpu_to_le32(0);
EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
}
return 0;
}
/*
* ext4_xattr_set_handle()
*
* 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
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
const char *name, const void *value, size_t value_len,
int flags)
{
struct ext4_xattr_info i = {
.name_index = name_index,
.name = name,
.value = value,
.value_len = value_len,
};
struct ext4_xattr_ibody_find is = {
.s = { .not_found = -ENODATA, },
};
struct ext4_xattr_block_find bs = {
.s = { .not_found = -ENODATA, },
};
unsigned long no_expand;
int error;
if (!name)
return -EINVAL;
if (strlen(name) > 255)
return -ERANGE;
down_write(&EXT4_I(inode)->xattr_sem);
no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
error = ext4_get_inode_loc(inode, &is.iloc);
if (error)
goto cleanup;
error = ext4_journal_get_write_access(handle, is.iloc.bh);
if (error)
goto cleanup;
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;
}
error = ext4_xattr_ibody_find(inode, &i, &is);
if (error)
goto cleanup;
if (is.s.not_found)
error = ext4_xattr_block_find(inode, &i, &bs);
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;
}
if (!value) {
if (!is.s.not_found)
error = ext4_xattr_ibody_set(handle, inode, &i, &is);
else if (!bs.s.not_found)
error = ext4_xattr_block_set(handle, inode, &i, &bs);
} else {
error = ext4_xattr_ibody_set(handle, inode, &i, &is);
if (!error && !bs.s.not_found) {
i.value = NULL;
error = ext4_xattr_block_set(handle, inode, &i, &bs);
} else if (error == -ENOSPC) {
if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
error = ext4_xattr_block_find(inode, &i, &bs);
if (error)
goto cleanup;
}
error = ext4_xattr_block_set(handle, inode, &i, &bs);
if (error)
goto cleanup;
if (!is.s.not_found) {
i.value = NULL;
error = ext4_xattr_ibody_set(handle, inode, &i,
&is);
}
}
}
if (!error) {
ext4_xattr_update_super_block(handle, inode->i_sb);
inode->i_ctime = ext4_current_time(inode);
if (!value)
EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
/*
* The bh is consumed by ext4_mark_iloc_dirty, even with
* error != 0.
*/
is.iloc.bh = NULL;
if (IS_SYNC(inode))
ext4_handle_sync(handle);
}
cleanup:
brelse(is.iloc.bh);
brelse(bs.bh);
if (no_expand == 0)
EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
up_write(&EXT4_I(inode)->xattr_sem);
return error;
}
/*
* ext4_xattr_set()
*
* Like ext4_xattr_set_handle, but start from an inode. This extended
* attribute modification is a filesystem transaction by itself.
*
* Returns 0, or a negative error number on failure.
*/
int
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
const void *value, size_t value_len, int flags)
{
handle_t *handle;
int error, retries = 0;
retry:
handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
} else {
int error2;
error = ext4_xattr_set_handle(handle, inode, name_index, name,
value, value_len, flags);
error2 = ext4_journal_stop(handle);
if (error == -ENOSPC &&
ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
if (error == 0)
error = error2;
}
return error;
}
/*
* 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;
int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
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)) {
ext4_error(inode->i_sb, __func__,
"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;
i.value_len = size;
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;
}
/*
* ext4_xattr_delete_inode()
*
* 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
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
{
struct buffer_head *bh = NULL;
if (!EXT4_I(inode)->i_file_acl)
goto cleanup;
bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
if (!bh) {
ext4_error(inode->i_sb, __func__,
"inode %lu: block %llu read error", inode->i_ino,
EXT4_I(inode)->i_file_acl);
goto cleanup;
}
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1)) {
ext4_error(inode->i_sb, __func__,
"inode %lu: bad block %llu", inode->i_ino,
EXT4_I(inode)->i_file_acl);
goto cleanup;
}
ext4_xattr_release_block(handle, inode, bh);
EXT4_I(inode)->i_file_acl = 0;
cleanup:
brelse(bh);
}
/*
* ext4_xattr_put_super()
*
* This is called when a file system is unmounted.
*/
void
ext4_xattr_put_super(struct super_block *sb)
{
mb_cache_shrink(sb->s_bdev);
}
/*
* ext4_xattr_cache_insert()
*
* 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
ext4_xattr_cache_insert(struct buffer_head *bh)
{
__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
struct mb_cache_entry *ce;
int error;
ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
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);
}
}
/*
* ext4_xattr_cmp()
*
* 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
ext4_xattr_cmp(struct ext4_xattr_header *header1,
struct ext4_xattr_header *header2)
{
struct ext4_xattr_entry *entry1, *entry2;
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;
entry1 = EXT4_XATTR_NEXT(entry1);
entry2 = EXT4_XATTR_NEXT(entry2);
}
if (!IS_LAST_ENTRY(entry2))
return 1;
return 0;
}
/*
* ext4_xattr_cache_find()
*
* 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 *
ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
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:
ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
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) {
ext4_error(inode->i_sb, __func__,
"inode %lu: block %lu read error",
inode->i_ino, (unsigned long) ce->e_block);
} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
EXT4_XATTR_REFCOUNT_MAX) {
ea_idebug(inode, "block %lu refcount %d>=%d",
(unsigned long) ce->e_block,
le32_to_cpu(BHDR(bh)->h_refcount),
EXT4_XATTR_REFCOUNT_MAX);
} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
*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
/*
* ext4_xattr_hash_entry()
*
* Compute the hash of an extended attribute.
*/
static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
struct ext4_xattr_entry *entry)
{
__u32 hash = 0;
char *name = entry->e_name;
int n;
for (n = 0; n < entry->e_name_len; n++) {
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) +
EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
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
/*
* ext4_xattr_rehash()
*
* Re-compute the extended attribute hash value after an entry has changed.
*/
static void ext4_xattr_rehash(struct ext4_xattr_header *header,
struct ext4_xattr_entry *entry)
{
struct ext4_xattr_entry *here;
__u32 hash = 0;
ext4_xattr_hash_entry(header, entry);
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);
here = EXT4_XATTR_NEXT(here);
}
header->h_hash = cpu_to_le32(hash);
}
#undef BLOCK_HASH_SHIFT
int __init
init_ext4_xattr(void)
{
ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
sizeof(struct mb_cache_entry) +
sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
if (!ext4_xattr_cache)
return -ENOMEM;
return 0;
}
void
exit_ext4_xattr(void)
{
if (ext4_xattr_cache)
mb_cache_destroy(ext4_xattr_cache);
ext4_xattr_cache = NULL;
}