- 根目录:
- fs
- ext3
- xattr.c
/*
* linux/fs/ext3/xattr.c
*
* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
*
* Fix by Harrison Xing <harrison@mountainviewdata.com>.
* Ext3 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
* ----------------
* EXT3_I(inode)->i_file_acl is protected by EXT3_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 "ext3.h"
#include <linux/mbcache.h>
#include <linux/quotaops.h>
#include "xattr.h"
#include "acl.h"
#define BHDR(bh) ((struct ext3_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr))
#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
#define IHDR(inode, raw_inode) \
((struct ext3_xattr_ibody_header *) \
((void *)raw_inode + \
EXT3_GOOD_OLD_INODE_SIZE + \
EXT3_I(inode)->i_extra_isize))
#define IFIRST(hdr) ((struct ext3_xattr_entry *)((hdr)+1))
#ifdef EXT3_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 ext3_xattr_cache_insert(struct buffer_head *);
static struct buffer_head *ext3_xattr_cache_find(struct inode *,
struct ext3_xattr_header *,
struct mb_cache_entry **);
static void ext3_xattr_rehash(struct ext3_xattr_header *,
struct ext3_xattr_entry *);
static int ext3_xattr_list(struct dentry *dentry, char *buffer,
size_t buffer_size);
static struct mb_cache *ext3_xattr_cache;
static const struct xattr_handler *ext3_xattr_handler_map[] = {
[EXT3_XATTR_INDEX_USER] = &ext3_xattr_user_handler,
#ifdef CONFIG_EXT3_FS_POSIX_ACL
[EXT3_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
[EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
#endif
[EXT3_XATTR_INDEX_TRUSTED] = &ext3_xattr_trusted_handler,
#ifdef CONFIG_EXT3_FS_SECURITY
[EXT3_XATTR_INDEX_SECURITY] = &ext3_xattr_security_handler,
#endif
};
const struct xattr_handler *ext3_xattr_handlers[] = {
&ext3_xattr_user_handler,
&ext3_xattr_trusted_handler,
#ifdef CONFIG_EXT3_FS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
#ifdef CONFIG_EXT3_FS_SECURITY
&ext3_xattr_security_handler,
#endif
NULL
};
static inline const struct xattr_handler *
ext3_xattr_handler(int name_index)
{
const struct xattr_handler *handler = NULL;
if (name_index > 0 && name_index < ARRAY_SIZE(ext3_xattr_handler_map))
handler = ext3_xattr_handler_map[name_index];
return handler;
}
/*
* Inode operation listxattr()
*
* dentry->d_inode->i_mutex: don't care
*/
ssize_t
ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
return ext3_xattr_list(dentry, buffer, size);
}
static int
ext3_xattr_check_names(struct ext3_xattr_entry *entry, void *end)
{
while (!IS_LAST_ENTRY(entry)) {
struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(entry);
if ((void *)next >= end)
return -EIO;
entry = next;
}
return 0;
}
static inline int
ext3_xattr_check_block(struct buffer_head *bh)
{
int error;
if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
return -EIO;
error = ext3_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
return error;
}
static inline int
ext3_xattr_check_entry(struct ext3_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
ext3_xattr_find_entry(struct ext3_xattr_entry **pentry, int name_index,
const char *name, size_t size, int sorted)
{
struct ext3_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 = EXT3_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 && ext3_xattr_check_entry(entry, size))
return -EIO;
return cmp ? -ENODATA : 0;
}
static int
ext3_xattr_block_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
struct buffer_head *bh = NULL;
struct ext3_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 (!EXT3_I(inode)->i_file_acl)
goto cleanup;
ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
bh = sb_bread(inode->i_sb, EXT3_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 (ext3_xattr_check_block(bh)) {
bad_block: ext3_error(inode->i_sb, __func__,
"inode %lu: bad block "E3FSBLK, inode->i_ino,
EXT3_I(inode)->i_file_acl);
error = -EIO;
goto cleanup;
}
ext3_xattr_cache_insert(bh);
entry = BFIRST(bh);
error = ext3_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
ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
struct ext3_xattr_ibody_header *header;
struct ext3_xattr_entry *entry;
struct ext3_inode *raw_inode;
struct ext3_iloc iloc;
size_t size;
void *end;
int error;
if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
return -ENODATA;
error = ext3_get_inode_loc(inode, &iloc);
if (error)
return error;
raw_inode = ext3_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
entry = IFIRST(header);
end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
error = ext3_xattr_check_names(entry, end);
if (error)
goto cleanup;
error = ext3_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;
}
/*
* ext3_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
ext3_xattr_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
int error;
down_read(&EXT3_I(inode)->xattr_sem);
error = ext3_xattr_ibody_get(inode, name_index, name, buffer,
buffer_size);
if (error == -ENODATA)
error = ext3_xattr_block_get(inode, name_index, name, buffer,
buffer_size);
up_read(&EXT3_I(inode)->xattr_sem);
return error;
}
static int
ext3_xattr_list_entries(struct dentry *dentry, struct ext3_xattr_entry *entry,
char *buffer, size_t buffer_size)
{
size_t rest = buffer_size;
for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
const struct xattr_handler *handler =
ext3_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
ext3_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 (!EXT3_I(inode)->i_file_acl)
goto cleanup;
ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
bh = sb_bread(inode->i_sb, EXT3_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 (ext3_xattr_check_block(bh)) {
ext3_error(inode->i_sb, __func__,
"inode %lu: bad block "E3FSBLK, inode->i_ino,
EXT3_I(inode)->i_file_acl);
error = -EIO;
goto cleanup;
}
ext3_xattr_cache_insert(bh);
error = ext3_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
cleanup:
brelse(bh);
return error;
}
static int
ext3_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
struct inode *inode = dentry->d_inode;
struct ext3_xattr_ibody_header *header;
struct ext3_inode *raw_inode;
struct ext3_iloc iloc;
void *end;
int error;
if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
return 0;
error = ext3_get_inode_loc(inode, &iloc);
if (error)
return error;
raw_inode = ext3_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
error = ext3_xattr_check_names(IFIRST(header), end);
if (error)
goto cleanup;
error = ext3_xattr_list_entries(dentry, IFIRST(header),
buffer, buffer_size);
cleanup:
brelse(iloc.bh);
return error;
}
/*
* ext3_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
ext3_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
int i_error, b_error;
down_read(&EXT3_I(dentry->d_inode)->xattr_sem);
i_error = ext3_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 = ext3_xattr_block_list(dentry, buffer, buffer_size);
if (b_error < 0)
i_error = 0;
}
up_read(&EXT3_I(dentry->d_inode)->xattr_sem);
return i_error + b_error;
}
/*
* If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is
* not set, set it.
*/
static void ext3_xattr_update_super_block(handle_t *handle,
struct super_block *sb)
{
if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR))
return;
if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) {
EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR);
ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
}
}
/*
* Release the xattr block BH: If the reference count is > 1, decrement
* it; otherwise free the block.
*/
static void
ext3_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(ext3_xattr_cache, bh->b_bdev, bh->b_blocknr);
error = ext3_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);
ext3_free_blocks(handle, inode, bh->b_blocknr, 1);
get_bh(bh);
ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
} else {
le32_add_cpu(&BHDR(bh)->h_refcount, -1);
error = ext3_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));
if (ce)
mb_cache_entry_release(ce);
}
unlock_buffer(bh);
out:
ext3_std_error(inode->i_sb, error);
return;
}
struct ext3_xattr_info {
int name_index;
const char *name;
const void *value;
size_t value_len;
};
struct ext3_xattr_search {
struct ext3_xattr_entry *first;
void *base;
void *end;
struct ext3_xattr_entry *here;
int not_found;
};
static int
ext3_xattr_set_entry(struct ext3_xattr_info *i, struct ext3_xattr_search *s)
{
struct ext3_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 = EXT3_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 += EXT3_XATTR_SIZE(size);
}
free += EXT3_XATTR_LEN(name_len);
}
if (i->value) {
if (free < EXT3_XATTR_SIZE(i->value_len) ||
free < EXT3_XATTR_LEN(name_len) +
EXT3_XATTR_SIZE(i->value_len))
return -ENOSPC;
}
if (i->value && s->not_found) {
/* Insert the new name. */
size_t size = EXT3_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 = EXT3_XATTR_SIZE(
le32_to_cpu(s->here->e_value_size));
if (i->value && size == EXT3_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 - EXT3_XATTR_PAD, 0,
EXT3_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 = EXT3_XATTR_NEXT(last);
}
}
if (!i->value) {
/* Remove the old name. */
size_t size = EXT3_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 = EXT3_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 - EXT3_XATTR_PAD, 0,
EXT3_XATTR_PAD); /* Clear the pad bytes. */
memcpy(val, i->value, i->value_len);
}
}
return 0;
}
struct ext3_xattr_block_find {
struct ext3_xattr_search s;
struct buffer_head *bh;
};
static int
ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
struct ext3_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 (EXT3_I(inode)->i_file_acl) {
/* The inode already has an extended attribute block. */
bs->bh = sb_bread(sb, EXT3_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 (ext3_xattr_check_block(bs->bh)) {
ext3_error(sb, __func__,
"inode %lu: bad block "E3FSBLK, inode->i_ino,
EXT3_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 = ext3_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
ext3_xattr_block_set(handle_t *handle, struct inode *inode,
struct ext3_xattr_info *i,
struct ext3_xattr_block_find *bs)
{
struct super_block *sb = inode->i_sb;
struct buffer_head *new_bh = NULL;
struct ext3_xattr_search *s = &bs->s;
struct mb_cache_entry *ce = NULL;
int error = 0;
#define header(x) ((struct ext3_xattr_header *)(x))
if (i->value && i->value_len > sb->s_blocksize)
return -ENOSPC;
if (s->base) {
ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
bs->bh->b_blocknr);
error = ext3_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 = ext3_xattr_set_entry(i, s);
if (!error) {
if (!IS_LAST_ENTRY(s->first))
ext3_xattr_rehash(header(s->base),
s->here);
ext3_xattr_cache_insert(bs->bh);
}
unlock_buffer(bs->bh);
if (error == -EIO)
goto bad_block;
if (!error)
error = ext3_journal_dirty_metadata(handle,
bs->bh);
if (error)
goto cleanup;
goto inserted;
} else {
int offset = (char *)s->here - bs->bh->b_data;
unlock_buffer(bs->bh);
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(EXT3_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 = ext3_xattr_set_entry(i, s);
if (error == -EIO)
goto bad_block;
if (error)
goto cleanup;
if (!IS_LAST_ENTRY(s->first))
ext3_xattr_rehash(header(s->base), s->here);
inserted:
if (!IS_LAST_ENTRY(s->first)) {
new_bh = ext3_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 = dquot_alloc_block(inode, 1);
if (error)
goto cleanup;
error = ext3_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 = ext3_journal_dirty_metadata(handle,
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 */
ext3_fsblk_t goal = ext3_group_first_block_no(sb,
EXT3_I(inode)->i_block_group);
ext3_fsblk_t block;
/*
* Protect us agaist concurrent allocations to the
* same inode from ext3_..._writepage(). Reservation
* code does not expect racing allocations.
*/
mutex_lock(&EXT3_I(inode)->truncate_mutex);
block = ext3_new_block(handle, inode, goal, &error);
mutex_unlock(&EXT3_I(inode)->truncate_mutex);
if (error)
goto cleanup;
ea_idebug(inode, "creating block %d", block);
new_bh = sb_getblk(sb, block);
if (unlikely(!new_bh)) {
getblk_failed:
ext3_free_blocks(handle, inode, block, 1);
error = -ENOMEM;
goto cleanup;
}
lock_buffer(new_bh);
error = ext3_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);
ext3_xattr_cache_insert(new_bh);
error = ext3_journal_dirty_metadata(handle, new_bh);
if (error)
goto cleanup;
}
}
/* Update the inode. */
EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
/* Drop the previous xattr block. */
if (bs->bh && bs->bh != new_bh)
ext3_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:
dquot_free_block(inode, 1);
goto cleanup;
bad_block:
ext3_error(inode->i_sb, __func__,
"inode %lu: bad block "E3FSBLK, inode->i_ino,
EXT3_I(inode)->i_file_acl);
goto cleanup;
#undef header
}
struct ext3_xattr_ibody_find {
struct ext3_xattr_search s;
struct ext3_iloc iloc;
};
static int
ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
struct ext3_xattr_ibody_find *is)
{
struct ext3_xattr_ibody_header *header;
struct ext3_inode *raw_inode;
int error;
if (EXT3_I(inode)->i_extra_isize == 0)
return 0;
raw_inode = ext3_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 + EXT3_SB(inode->i_sb)->s_inode_size;
if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
error = ext3_xattr_check_names(IFIRST(header), is->s.end);
if (error)
return error;
/* Find the named attribute. */
error = ext3_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
ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
struct ext3_xattr_info *i,
struct ext3_xattr_ibody_find *is)
{
struct ext3_xattr_ibody_header *header;
struct ext3_xattr_search *s = &is->s;
int error;
if (EXT3_I(inode)->i_extra_isize == 0)
return -ENOSPC;
error = ext3_xattr_set_entry(i, s);
if (error)
return error;
header = IHDR(inode, ext3_raw_inode(&is->iloc));
if (!IS_LAST_ENTRY(s->first)) {
header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
ext3_set_inode_state(inode, EXT3_STATE_XATTR);
} else {
header->h_magic = cpu_to_le32(0);
ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
}
return 0;
}
/*
* ext3_xattr_set_handle()
*
* Create, replace or remove an extended attribute for this inode. Value
* 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
ext3_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 ext3_xattr_info i = {
.name_index = name_index,
.name = name,
.value = value,
.value_len = value_len,
};
struct ext3_xattr_ibody_find is = {
.s = { .not_found = -ENODATA, },
};
struct ext3_xattr_block_find bs = {
.s = { .not_found = -ENODATA, },
};
int error;
if (!name)
return -EINVAL;
if (strlen(name) > 255)
return -ERANGE;
down_write(&EXT3_I(inode)->xattr_sem);
error = ext3_get_inode_loc(inode, &is.iloc);
if (error)
goto cleanup;
error = ext3_journal_get_write_access(handle, is.iloc.bh);
if (error)
goto cleanup;
if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
ext3_clear_inode_state(inode, EXT3_STATE_NEW);
}
error = ext3_xattr_ibody_find(inode, &i, &is);
if (error)
goto cleanup;
if (is.s.not_found)
error = ext3_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 = ext3_xattr_ibody_set(handle, inode, &i, &is);
else if (!bs.s.not_found)
error = ext3_xattr_block_set(handle, inode, &i, &bs);
} else {
error = ext3_xattr_ibody_set(handle, inode, &i, &is);
if (!error && !bs.s.not_found) {
i.value = NULL;
error = ext3_xattr_block_set(handle, inode, &i, &bs);
} else if (error == -ENOSPC) {
if (EXT3_I(inode)->i_file_acl && !bs.s.base) {
error = ext3_xattr_block_find(inode, &i, &bs);
if (error)
goto cleanup;
}
error = ext3_xattr_block_set(handle, inode, &i, &bs);
if (error)
goto cleanup;
if (!is.s.not_found) {
i.value = NULL;
error = ext3_xattr_ibody_set(handle, inode, &i,
&is);
}
}
}
if (!error) {
ext3_xattr_update_super_block(handle, inode->i_sb);
inode->i_ctime = CURRENT_TIME_SEC;
error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
/*
* The bh is consumed by ext3_mark_iloc_dirty, even with
* error != 0.
*/
is.iloc.bh = NULL;
if (IS_SYNC(inode))
handle->h_sync = 1;
}
cleanup:
brelse(is.iloc.bh);
brelse(bs.bh);
up_write(&EXT3_I(inode)->xattr_sem);
return error;
}
/*
* ext3_xattr_set()
*
* Like ext3_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
ext3_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 = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
} else {
int error2;
error = ext3_xattr_set_handle(handle, inode, name_index, name,
value, value_len, flags);
error2 = ext3_journal_stop(handle);
if (error == -ENOSPC &&
ext3_should_retry_alloc(inode->i_sb, &retries))
goto retry;
if (error == 0)
error = error2;
}
return error;
}
/*
* ext3_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
ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
{
struct buffer_head *bh = NULL;
if (!EXT3_I(inode)->i_file_acl)
goto cleanup;
bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
if (!bh) {
ext3_error(inode->i_sb, __func__,
"inode %lu: block "E3FSBLK" read error", inode->i_ino,
EXT3_I(inode)->i_file_acl);
goto cleanup;
}
if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1)) {
ext3_error(inode->i_sb, __func__,
"inode %lu: bad block "E3FSBLK, inode->i_ino,
EXT3_I(inode)->i_file_acl);
goto cleanup;
}
ext3_xattr_release_block(handle, inode, bh);
EXT3_I(inode)->i_file_acl = 0;
cleanup:
brelse(bh);
}
/*
* ext3_xattr_put_super()
*
* This is called when a file system is unmounted.
*/
void
ext3_xattr_put_super(struct super_block *sb)
{
mb_cache_shrink(sb->s_bdev);
}
/*
* ext3_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
ext3_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(ext3_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);
}
}
/*
* ext3_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
ext3_xattr_cmp(struct ext3_xattr_header *header1,
struct ext3_xattr_header *header2)
{
struct ext3_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 = EXT3_XATTR_NEXT(entry1);
entry2 = EXT3_XATTR_NEXT(entry2);
}
if (!IS_LAST_ENTRY(entry2))
return 1;
return 0;
}
/*
* ext3_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 *
ext3_xattr_cache_find(struct inode *inode, struct ext3_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(ext3_xattr_cache, 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) {
ext3_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) >=
EXT3_XATTR_REFCOUNT_MAX) {
ea_idebug(inode, "block %lu refcount %d>=%d",
(unsigned long) ce->e_block,
le32_to_cpu(BHDR(bh)->h_refcount),
EXT3_XATTR_REFCOUNT_MAX);
} else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
*pce = ce;
return bh;
}
brelse(bh);
ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
}
return NULL;
}
#define NAME_HASH_SHIFT 5
#define VALUE_HASH_SHIFT 16
/*
* ext3_xattr_hash_entry()
*
* Compute the hash of an extended attribute.
*/
static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
struct ext3_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) +
EXT3_XATTR_ROUND) >> EXT3_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
/*
* ext3_xattr_rehash()
*
* Re-compute the extended attribute hash value after an entry has changed.
*/
static void ext3_xattr_rehash(struct ext3_xattr_header *header,
struct ext3_xattr_entry *entry)
{
struct ext3_xattr_entry *here;
__u32 hash = 0;
ext3_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 = EXT3_XATTR_NEXT(here);
}
header->h_hash = cpu_to_le32(hash);
}
#undef BLOCK_HASH_SHIFT
int __init
init_ext3_xattr(void)
{
ext3_xattr_cache = mb_cache_create("ext3_xattr", 6);
if (!ext3_xattr_cache)
return -ENOMEM;
return 0;
}
void
exit_ext3_xattr(void)
{
if (ext3_xattr_cache)
mb_cache_destroy(ext3_xattr_cache);
ext3_xattr_cache = NULL;
}