kvj
/
linux-zen-server
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
linux-zen-server/fs/ext4/xattr.c

3225 lines
84 KiB
C
Raw Permalink Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* 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/iversion.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
#include "acl.h"
#ifdef EXT4_XATTR_DEBUG
# define ea_idebug(inode, fmt, ...) \
printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
# define ea_bdebug(bh, fmt, ...) \
printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
#else
# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#endif
static void ext4_xattr_block_cache_insert(struct mb_cache *,
struct buffer_head *);
static struct buffer_head *
ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
struct mb_cache_entry **);
static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
size_t value_count);
static __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value,
size_t value_count);
static void ext4_xattr_rehash(struct ext4_xattr_header *);
static const struct xattr_handler * const ext4_xattr_handler_map[] = {
[EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
#ifdef CONFIG_EXT4_FS_POSIX_ACL
[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
#endif
[EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4_FS_SECURITY
[EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
#endif
[EXT4_XATTR_INDEX_HURD] = &ext4_xattr_hurd_handler,
};
const struct xattr_handler *ext4_xattr_handlers[] = {
&ext4_xattr_user_handler,
&ext4_xattr_trusted_handler,
#ifdef CONFIG_EXT4_FS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
#ifdef CONFIG_EXT4_FS_SECURITY
&ext4_xattr_security_handler,
#endif
&ext4_xattr_hurd_handler,
NULL
};
#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \
inode->i_sb->s_fs_info)->s_ea_block_cache)
#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
inode->i_sb->s_fs_info)->s_ea_inode_cache)
static int
ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
struct inode *inode);
#ifdef CONFIG_LOCKDEP
void ext4_xattr_inode_set_class(struct inode *ea_inode)
{
struct ext4_inode_info *ei = EXT4_I(ea_inode);
lockdep_set_subclass(&ea_inode->i_rwsem, 1);
(void) ei; /* shut up clang warning if !CONFIG_LOCKDEP */
lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
}
#endif
static __le32 ext4_xattr_block_csum(struct inode *inode,
sector_t block_nr,
struct ext4_xattr_header *hdr)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
__u32 csum;
__le64 dsk_block_nr = cpu_to_le64(block_nr);
__u32 dummy_csum = 0;
int offset = offsetof(struct ext4_xattr_header, h_checksum);
csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
sizeof(dsk_block_nr));
csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
offset += sizeof(dummy_csum);
csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
EXT4_BLOCK_SIZE(inode->i_sb) - offset);
return cpu_to_le32(csum);
}
static int ext4_xattr_block_csum_verify(struct inode *inode,
struct buffer_head *bh)
{
struct ext4_xattr_header *hdr = BHDR(bh);
int ret = 1;
if (ext4_has_metadata_csum(inode->i_sb)) {
lock_buffer(bh);
ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
bh->b_blocknr, hdr));
unlock_buffer(bh);
}
return ret;
}
static void ext4_xattr_block_csum_set(struct inode *inode,
struct buffer_head *bh)
{
if (ext4_has_metadata_csum(inode->i_sb))
BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
bh->b_blocknr, BHDR(bh));
}
static inline const struct xattr_handler *
ext4_xattr_handler(int name_index)
{
const 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;
}
static int
check_xattrs(struct inode *inode, struct buffer_head *bh,
struct ext4_xattr_entry *entry, void *end, void *value_start,
const char *function, unsigned int line)
{
struct ext4_xattr_entry *e = entry;
int err = -EFSCORRUPTED;
char *err_str;
if (bh) {
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1)) {
err_str = "invalid header";
goto errout;
}
if (buffer_verified(bh))
return 0;
if (!ext4_xattr_block_csum_verify(inode, bh)) {
err = -EFSBADCRC;
err_str = "invalid checksum";
goto errout;
}
} else {
struct ext4_xattr_ibody_header *header = value_start;
header -= 1;
if (end - (void *)header < sizeof(*header) + sizeof(u32)) {
err_str = "in-inode xattr block too small";
goto errout;
}
if (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
err_str = "bad magic number in in-inode xattr";
goto errout;
}
}
/* Find the end of the names list */
while (!IS_LAST_ENTRY(e)) {
struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
if ((void *)next >= end) {
err_str = "e_name out of bounds";
goto errout;
}
if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) {
err_str = "bad e_name length";
goto errout;
}
e = next;
}
/* Check the values */
while (!IS_LAST_ENTRY(entry)) {
u32 size = le32_to_cpu(entry->e_value_size);
unsigned long ea_ino = le32_to_cpu(entry->e_value_inum);
if (!ext4_has_feature_ea_inode(inode->i_sb) && ea_ino) {
err_str = "ea_inode specified without ea_inode feature enabled";
goto errout;
}
if (ea_ino && ((ea_ino == EXT4_ROOT_INO) ||
!ext4_valid_inum(inode->i_sb, ea_ino))) {
err_str = "invalid ea_ino";
goto errout;
}
if (size > EXT4_XATTR_SIZE_MAX) {
err_str = "e_value size too large";
goto errout;
}
if (size != 0 && entry->e_value_inum == 0) {
u16 offs = le16_to_cpu(entry->e_value_offs);
void *value;
/*
* The value cannot overlap the names, and the value
* with padding cannot extend beyond 'end'. Check both
* the padded and unpadded sizes, since the size may
* overflow to 0 when adding padding.
*/
if (offs > end - value_start) {
err_str = "e_value out of bounds";
goto errout;
}
value = value_start + offs;
if (value < (void *)e + sizeof(u32) ||
size > end - value ||
EXT4_XATTR_SIZE(size) > end - value) {
err_str = "overlapping e_value ";
goto errout;
}
}
entry = EXT4_XATTR_NEXT(entry);
}
if (bh)
set_buffer_verified(bh);
return 0;
errout:
if (bh)
__ext4_error_inode(inode, function, line, 0, -err,
"corrupted xattr block %llu: %s",
(unsigned long long) bh->b_blocknr,
err_str);
else
__ext4_error_inode(inode, function, line, 0, -err,
"corrupted in-inode xattr: %s", err_str);
return err;
}
static inline int
__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
const char *function, unsigned int line)
{
return check_xattrs(inode, bh, BFIRST(bh), bh->b_data + bh->b_size,
bh->b_data, function, line);
}
#define ext4_xattr_check_block(inode, bh) \
__ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
static inline int
__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
void *end, const char *function, unsigned int line)
{
return check_xattrs(inode, NULL, IFIRST(header), end, IFIRST(header),
function, line);
}
#define xattr_check_inode(inode, header, end) \
__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
static int
xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
void *end, int name_index, const char *name, int sorted)
{
struct ext4_xattr_entry *entry, *next;
size_t name_len;
int cmp = 1;
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
next = EXT4_XATTR_NEXT(entry);
if ((void *) next >= end) {
EXT4_ERROR_INODE(inode, "corrupted xattr entries");
return -EFSCORRUPTED;
}
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;
return cmp ? -ENODATA : 0;
}
static u32
ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
{
return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
}
static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
{
return ((u64)ea_inode->i_ctime.tv_sec << 32) |
(u32) inode_peek_iversion_raw(ea_inode);
}
static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
{
ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
}
static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
{
return (u32)ea_inode->i_atime.tv_sec;
}
static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
{
ea_inode->i_atime.tv_sec = hash;
}
/*
* Read the EA value from an inode.
*/
static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
{
int blocksize = 1 << ea_inode->i_blkbits;
int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
int tail_size = (size % blocksize) ?: blocksize;
struct buffer_head *bhs_inline[8];
struct buffer_head **bhs = bhs_inline;
int i, ret;
if (bh_count > ARRAY_SIZE(bhs_inline)) {
bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
if (!bhs)
return -ENOMEM;
}
ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
true /* wait */, bhs);
if (ret)
goto free_bhs;
for (i = 0; i < bh_count; i++) {
/* There shouldn't be any holes in ea_inode. */
if (!bhs[i]) {
ret = -EFSCORRUPTED;
goto put_bhs;
}
memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
i < bh_count - 1 ? blocksize : tail_size);
}
ret = 0;
put_bhs:
for (i = 0; i < bh_count; i++)
brelse(bhs[i]);
free_bhs:
if (bhs != bhs_inline)
kfree(bhs);
return ret;
}
#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
u32 ea_inode_hash, struct inode **ea_inode)
{
struct inode *inode;
int err;
/*
* We have to check for this corruption early as otherwise
* iget_locked() could wait indefinitely for the state of our
* parent inode.
*/
if (parent->i_ino == ea_ino) {
ext4_error(parent->i_sb,
"Parent and EA inode have the same ino %lu", ea_ino);
return -EFSCORRUPTED;
}
inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
ext4_error(parent->i_sb,
"error while reading EA inode %lu err=%d", ea_ino,
err);
return err;
}
ext4_xattr_inode_set_class(inode);
/*
* Check whether this is an old Lustre-style xattr inode. Lustre
* implementation does not have hash validation, rather it has a
* backpointer from ea_inode to the parent inode.
*/
if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
inode->i_generation == parent->i_generation) {
ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
ext4_xattr_inode_set_ref(inode, 1);
} else {
inode_lock(inode);
inode->i_flags |= S_NOQUOTA;
inode_unlock(inode);
}
*ea_inode = inode;
return 0;
}
/* Remove entry from mbcache when EA inode is getting evicted */
void ext4_evict_ea_inode(struct inode *inode)
{
struct mb_cache_entry *oe;
if (!EA_INODE_CACHE(inode))
return;
/* Wait for entry to get unused so that we can remove it */
while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
mb_cache_entry_wait_unused(oe);
mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
}
}
static int
ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
struct ext4_xattr_entry *entry, void *buffer,
size_t size)
{
u32 hash;
/* Verify stored hash matches calculated hash. */
hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
if (hash != ext4_xattr_inode_get_hash(ea_inode))
return -EFSCORRUPTED;
if (entry) {
__le32 e_hash, tmp_data;
/* Verify entry hash. */
tmp_data = cpu_to_le32(hash);
e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
&tmp_data, 1);
/* All good? */
if (e_hash == entry->e_hash)
return 0;
/*
* Not good. Maybe the entry hash was calculated
* using the buggy signed char version?
*/
e_hash = ext4_xattr_hash_entry_signed(entry->e_name, entry->e_name_len,
&tmp_data, 1);
/* Still no match - bad */
if (e_hash != entry->e_hash)
return -EFSCORRUPTED;
/* Let people know about old hash */
pr_warn_once("ext4: filesystem with signed xattr name hash");
}
return 0;
}
/*
* Read xattr value from the EA inode.
*/
static int
ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
void *buffer, size_t size)
{
struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
struct inode *ea_inode;
int err;
err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
le32_to_cpu(entry->e_hash), &ea_inode);
if (err) {
ea_inode = NULL;
goto out;
}
if (i_size_read(ea_inode) != size) {
ext4_warning_inode(ea_inode,
"ea_inode file size=%llu entry size=%zu",
i_size_read(ea_inode), size);
err = -EFSCORRUPTED;
goto out;
}
err = ext4_xattr_inode_read(ea_inode, buffer, size);
if (err)
goto out;
if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
size);
if (err) {
ext4_warning_inode(ea_inode,
"EA inode hash validation failed");
goto out;
}
if (ea_inode_cache)
mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
ext4_xattr_inode_get_hash(ea_inode),
ea_inode->i_ino, true /* reusable */);
}
out:
iput(ea_inode);
return err;
}
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;
void *end;
int error;
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
name_index, name, buffer, (long)buffer_size);
if (!EXT4_I(inode)->i_file_acl)
return -ENODATA;
ea_idebug(inode, "reading block %llu",
(unsigned long long)EXT4_I(inode)->i_file_acl);
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh))
return PTR_ERR(bh);
ea_bdebug(bh, "b_count=%d, refcount=%d",
atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
error = ext4_xattr_check_block(inode, bh);
if (error)
goto cleanup;
ext4_xattr_block_cache_insert(ea_block_cache, bh);
entry = BFIRST(bh);
end = bh->b_data + bh->b_size;
error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
if (error)
goto cleanup;
size = le32_to_cpu(entry->e_value_size);
error = -ERANGE;
if (unlikely(size > EXT4_XATTR_SIZE_MAX))
goto cleanup;
if (buffer) {
if (size > buffer_size)
goto cleanup;
if (entry->e_value_inum) {
error = ext4_xattr_inode_get(inode, entry, buffer,
size);
if (error)
goto cleanup;
} else {
u16 offset = le16_to_cpu(entry->e_value_offs);
void *p = bh->b_data + offset;
if (unlikely(p + size > end))
goto cleanup;
memcpy(buffer, p, size);
}
}
error = size;
cleanup:
brelse(bh);
return error;
}
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_test_inode_state(inode, 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);
end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
error = xattr_check_inode(inode, header, end);
if (error)
goto cleanup;
entry = IFIRST(header);
error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
if (error)
goto cleanup;
size = le32_to_cpu(entry->e_value_size);
error = -ERANGE;
if (unlikely(size > EXT4_XATTR_SIZE_MAX))
goto cleanup;
if (buffer) {
if (size > buffer_size)
goto cleanup;
if (entry->e_value_inum) {
error = ext4_xattr_inode_get(inode, entry, buffer,
size);
if (error)
goto cleanup;
} else {
u16 offset = le16_to_cpu(entry->e_value_offs);
void *p = (void *)IFIRST(header) + offset;
if (unlikely(p + size > end))
goto cleanup;
memcpy(buffer, p, 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;
if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
return -EIO;
if (strlen(name) > 255)
return -ERANGE;
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)) {
const struct xattr_handler *handler =
ext4_xattr_handler(entry->e_name_index);
if (handler && (!handler->list || handler->list(dentry))) {
const char *prefix = handler->prefix ?: handler->name;
size_t prefix_len = strlen(prefix);
size_t size = prefix_len + entry->e_name_len + 1;
if (buffer) {
if (size > rest)
return -ERANGE;
memcpy(buffer, prefix, prefix_len);
buffer += prefix_len;
memcpy(buffer, entry->e_name, entry->e_name_len);
buffer += entry->e_name_len;
*buffer++ = 0;
}
rest -= size;
}
}
return buffer_size - rest; /* total size */
}
static int
ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
struct inode *inode = d_inode(dentry);
struct buffer_head *bh = NULL;
int error;
ea_idebug(inode, "buffer=%p, buffer_size=%ld",
buffer, (long)buffer_size);
if (!EXT4_I(inode)->i_file_acl)
return 0;
ea_idebug(inode, "reading block %llu",
(unsigned long long)EXT4_I(inode)->i_file_acl);
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh))
return PTR_ERR(bh);
ea_bdebug(bh, "b_count=%d, refcount=%d",
atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
error = ext4_xattr_check_block(inode, bh);
if (error)
goto cleanup;
ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), 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 = d_inode(dentry);
struct ext4_xattr_ibody_header *header;
struct ext4_inode *raw_inode;
struct ext4_iloc iloc;
void *end;
int error;
if (!ext4_test_inode_state(inode, 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 = xattr_check_inode(inode, header, end);
if (error)
goto cleanup;
error = ext4_xattr_list_entries(dentry, IFIRST(header),
buffer, buffer_size);
cleanup:
brelse(iloc.bh);
return error;
}
/*
* Inode operation listxattr()
*
* d_inode(dentry)->i_rwsem: don't care
*
* 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.
*/
ssize_t
ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
int ret, ret2;
down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
if (ret < 0)
goto errout;
if (buffer) {
buffer += ret;
buffer_size -= ret;
}
ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
if (ret < 0)
goto errout;
ret += ret2;
errout:
up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
return ret;
}
/*
* 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_feature_xattr(sb))
return;
BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
EXT4_JTR_NONE) == 0) {
lock_buffer(EXT4_SB(sb)->s_sbh);
ext4_set_feature_xattr(sb);
ext4_superblock_csum_set(sb);
unlock_buffer(EXT4_SB(sb)->s_sbh);
ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
}
}
int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
{
struct ext4_iloc iloc = { .bh = NULL };
struct buffer_head *bh = NULL;
struct ext4_inode *raw_inode;
struct ext4_xattr_ibody_header *header;
struct ext4_xattr_entry *entry;
qsize_t ea_inode_refs = 0;
void *end;
int ret;
lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
ret = ext4_get_inode_loc(inode, &iloc);
if (ret)
goto out;
raw_inode = ext4_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
ret = xattr_check_inode(inode, header, end);
if (ret)
goto out;
for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
entry = EXT4_XATTR_NEXT(entry))
if (entry->e_value_inum)
ea_inode_refs++;
}
if (EXT4_I(inode)->i_file_acl) {
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh)) {
ret = PTR_ERR(bh);
bh = NULL;
goto out;
}
ret = ext4_xattr_check_block(inode, bh);
if (ret)
goto out;
for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
entry = EXT4_XATTR_NEXT(entry))
if (entry->e_value_inum)
ea_inode_refs++;
}
*usage = ea_inode_refs + 1;
ret = 0;
out:
brelse(iloc.bh);
brelse(bh);
return ret;
}
static inline size_t round_up_cluster(struct inode *inode, size_t length)
{
struct super_block *sb = inode->i_sb;
size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
inode->i_blkbits);
size_t mask = ~(cluster_size - 1);
return (length + cluster_size - 1) & mask;
}
static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
{
int err;
err = dquot_alloc_inode(inode);
if (err)
return err;
err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
if (err)
dquot_free_inode(inode);
return err;
}
static void ext4_xattr_inode_free_quota(struct inode *parent,
struct inode *ea_inode,
size_t len)
{
if (ea_inode &&
ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
return;
dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
dquot_free_inode(parent);
}
int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
struct buffer_head *block_bh, size_t value_len,
bool is_create)
{
int credits;
int blocks;
/*
* 1) Owner inode update
* 2) Ref count update on old xattr block
* 3) new xattr block
* 4) block bitmap update for new xattr block
* 5) group descriptor for new xattr block
* 6) block bitmap update for old xattr block
* 7) group descriptor for old block
*
* 6 & 7 can happen if we have two racing threads T_a and T_b
* which are each trying to set an xattr on inodes I_a and I_b
* which were both initially sharing an xattr block.
*/
credits = 7;
/* Quota updates. */
credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
/*
* In case of inline data, we may push out the data to a block,
* so we need to reserve credits for this eventuality
*/
if (inode && ext4_has_inline_data(inode))
credits += ext4_writepage_trans_blocks(inode) + 1;
/* We are done if ea_inode feature is not enabled. */
if (!ext4_has_feature_ea_inode(sb))
return credits;
/* New ea_inode, inode map, block bitmap, group descriptor. */
credits += 4;
/* Data blocks. */
blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
/* Indirection block or one level of extent tree. */
blocks += 1;
/* Block bitmap and group descriptor updates for each block. */
credits += blocks * 2;
/* Blocks themselves. */
credits += blocks;
if (!is_create) {
/* Dereference ea_inode holding old xattr value.
* Old ea_inode, inode map, block bitmap, group descriptor.
*/
credits += 4;
/* Data blocks for old ea_inode. */
blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
/* Indirection block or one level of extent tree for old
* ea_inode.
*/
blocks += 1;
/* Block bitmap and group descriptor updates for each block. */
credits += blocks * 2;
}
/* We may need to clone the existing xattr block in which case we need
* to increment ref counts for existing ea_inodes referenced by it.
*/
if (block_bh) {
struct ext4_xattr_entry *entry = BFIRST(block_bh);
for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
if (entry->e_value_inum)
/* Ref count update on ea_inode. */
credits += 1;
}
return credits;
}
static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
int ref_change)
{
struct ext4_iloc iloc;
s64 ref_count;
int ret;
inode_lock(ea_inode);
ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
if (ret)
goto out;
ref_count = ext4_xattr_inode_get_ref(ea_inode);
ref_count += ref_change;
ext4_xattr_inode_set_ref(ea_inode, ref_count);
if (ref_change > 0) {
WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
ea_inode->i_ino, ref_count);
if (ref_count == 1) {
WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
ea_inode->i_ino, ea_inode->i_nlink);
set_nlink(ea_inode, 1);
ext4_orphan_del(handle, ea_inode);
}
} else {
WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
ea_inode->i_ino, ref_count);
if (ref_count == 0) {
WARN_ONCE(ea_inode->i_nlink != 1,
"EA inode %lu i_nlink=%u",
ea_inode->i_ino, ea_inode->i_nlink);
clear_nlink(ea_inode);
ext4_orphan_add(handle, ea_inode);
}
}
ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
if (ret)
ext4_warning_inode(ea_inode,
"ext4_mark_iloc_dirty() failed ret=%d", ret);
out:
inode_unlock(ea_inode);
return ret;
}
static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
{
return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
}
static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
{
return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
}
static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
struct ext4_xattr_entry *first)
{
struct inode *ea_inode;
struct ext4_xattr_entry *entry;
struct ext4_xattr_entry *failed_entry;
unsigned int ea_ino;
int err, saved_err;
for (entry = first; !IS_LAST_ENTRY(entry);
entry = EXT4_XATTR_NEXT(entry)) {
if (!entry->e_value_inum)
continue;
ea_ino = le32_to_cpu(entry->e_value_inum);
err = ext4_xattr_inode_iget(parent, ea_ino,
le32_to_cpu(entry->e_hash),
&ea_inode);
if (err)
goto cleanup;
err = ext4_xattr_inode_inc_ref(handle, ea_inode);
if (err) {
ext4_warning_inode(ea_inode, "inc ref error %d", err);
iput(ea_inode);
goto cleanup;
}
iput(ea_inode);
}
return 0;
cleanup:
saved_err = err;
failed_entry = entry;
for (entry = first; entry != failed_entry;
entry = EXT4_XATTR_NEXT(entry)) {
if (!entry->e_value_inum)
continue;
ea_ino = le32_to_cpu(entry->e_value_inum);
err = ext4_xattr_inode_iget(parent, ea_ino,
le32_to_cpu(entry->e_hash),
&ea_inode);
if (err) {
ext4_warning(parent->i_sb,
"cleanup ea_ino %u iget error %d", ea_ino,
err);
continue;
}
err = ext4_xattr_inode_dec_ref(handle, ea_inode);
if (err)
ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
err);
iput(ea_inode);
}
return saved_err;
}
static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
struct buffer_head *bh, bool block_csum, bool dirty)
{
int error;
if (bh && dirty) {
if (block_csum)
ext4_xattr_block_csum_set(inode, bh);
error = ext4_handle_dirty_metadata(handle, NULL, bh);
if (error) {
ext4_warning(inode->i_sb, "Handle metadata (error %d)",
error);
return error;
}
}
return 0;
}
static void
ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
struct buffer_head *bh,
struct ext4_xattr_entry *first, bool block_csum,
struct ext4_xattr_inode_array **ea_inode_array,
int extra_credits, bool skip_quota)
{
struct inode *ea_inode;
struct ext4_xattr_entry *entry;
bool dirty = false;
unsigned int ea_ino;
int err;
int credits;
/* One credit for dec ref on ea_inode, one for orphan list addition, */
credits = 2 + extra_credits;
for (entry = first; !IS_LAST_ENTRY(entry);
entry = EXT4_XATTR_NEXT(entry)) {
if (!entry->e_value_inum)
continue;
ea_ino = le32_to_cpu(entry->e_value_inum);
err = ext4_xattr_inode_iget(parent, ea_ino,
le32_to_cpu(entry->e_hash),
&ea_inode);
if (err)
continue;
err = ext4_expand_inode_array(ea_inode_array, ea_inode);
if (err) {
ext4_warning_inode(ea_inode,
"Expand inode array err=%d", err);
iput(ea_inode);
continue;
}
err = ext4_journal_ensure_credits_fn(handle, credits, credits,
ext4_free_metadata_revoke_credits(parent->i_sb, 1),
ext4_xattr_restart_fn(handle, parent, bh, block_csum,
dirty));
if (err < 0) {
ext4_warning_inode(ea_inode, "Ensure credits err=%d",
err);
continue;
}
if (err > 0) {
err = ext4_journal_get_write_access(handle,
parent->i_sb, bh, EXT4_JTR_NONE);
if (err) {
ext4_warning_inode(ea_inode,
"Re-get write access err=%d",
err);
continue;
}
}
err = ext4_xattr_inode_dec_ref(handle, ea_inode);
if (err) {
ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
err);
continue;
}
if (!skip_quota)
ext4_xattr_inode_free_quota(parent, ea_inode,
le32_to_cpu(entry->e_value_size));
/*
* Forget about ea_inode within the same transaction that
* decrements the ref count. This avoids duplicate decrements in
* case the rest of the work spills over to subsequent
* transactions.
*/
entry->e_value_inum = 0;
entry->e_value_size = 0;
dirty = true;
}
if (dirty) {
/*
* Note that we are deliberately skipping csum calculation for
* the final update because we do not expect any journal
* restarts until xattr block is freed.
*/
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (err)
ext4_warning_inode(parent,
"handle dirty metadata err=%d", err);
}
}
/*
* 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 ext4_xattr_inode_array **ea_inode_array,
int extra_credits)
{
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
u32 hash, ref;
int error = 0;
BUFFER_TRACE(bh, "get_write_access");
error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
EXT4_JTR_NONE);
if (error)
goto out;
retry_ref:
lock_buffer(bh);
hash = le32_to_cpu(BHDR(bh)->h_hash);
ref = le32_to_cpu(BHDR(bh)->h_refcount);
if (ref == 1) {
ea_bdebug(bh, "refcount now=0; freeing");
/*
* This must happen under buffer lock for
* ext4_xattr_block_set() to reliably detect freed block
*/
if (ea_block_cache) {
struct mb_cache_entry *oe;
oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
bh->b_blocknr);
if (oe) {
unlock_buffer(bh);
mb_cache_entry_wait_unused(oe);
mb_cache_entry_put(ea_block_cache, oe);
goto retry_ref;
}
}
get_bh(bh);
unlock_buffer(bh);
if (ext4_has_feature_ea_inode(inode->i_sb))
ext4_xattr_inode_dec_ref_all(handle, inode, bh,
BFIRST(bh),
true /* block_csum */,
ea_inode_array,
extra_credits,
true /* skip_quota */);
ext4_free_blocks(handle, inode, bh, 0, 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
} else {
ref--;
BHDR(bh)->h_refcount = cpu_to_le32(ref);
if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
struct mb_cache_entry *ce;
if (ea_block_cache) {
ce = mb_cache_entry_get(ea_block_cache, hash,
bh->b_blocknr);
if (ce) {
set_bit(MBE_REUSABLE_B, &ce->e_flags);
mb_cache_entry_put(ea_block_cache, ce);
}
}
}
ext4_xattr_block_csum_set(inode, bh);
/*
* Beware of this ugliness: Releasing of xattr block references
* from different inodes can race and so we have to protect
* from a race where someone else frees the block (and releases
* its journal_head) before we are done dirtying the buffer. In
* nojournal mode this race is harmless and we actually cannot
* call ext4_handle_dirty_metadata() with locked buffer as
* that function can call sync_dirty_buffer() so for that case
* we handle the dirtying after unlocking the buffer.
*/
if (ext4_handle_valid(handle))
error = ext4_handle_dirty_metadata(handle, inode, bh);
unlock_buffer(bh);
if (!ext4_handle_valid(handle))
error = ext4_handle_dirty_metadata(handle, inode, bh);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
ea_bdebug(bh, "refcount now=%d; releasing",
le32_to_cpu(BHDR(bh)->h_refcount));
}
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)) {
if (!last->e_value_inum && last->e_value_size) {
size_t offs = le16_to_cpu(last->e_value_offs);
if (offs < *min_offs)
*min_offs = offs;
}
if (total)
*total += EXT4_XATTR_LEN(last->e_name_len);
}
return (*min_offs - ((void *)last - base) - sizeof(__u32));
}
/*
* Write the value of the EA in an inode.
*/
static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
const void *buf, int bufsize)
{
struct buffer_head *bh = NULL;
unsigned long block = 0;
int blocksize = ea_inode->i_sb->s_blocksize;
int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
int csize, wsize = 0;
int ret = 0, ret2 = 0;
int retries = 0;
retry:
while (ret >= 0 && ret < max_blocks) {
struct ext4_map_blocks map;
map.m_lblk = block += ret;
map.m_len = max_blocks -= ret;
ret = ext4_map_blocks(handle, ea_inode, &map,
EXT4_GET_BLOCKS_CREATE);
if (ret <= 0) {
ext4_mark_inode_dirty(handle, ea_inode);
if (ret == -ENOSPC &&
ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
ret = 0;
goto retry;
}
break;
}
}
if (ret < 0)
return ret;
block = 0;
while (wsize < bufsize) {
brelse(bh);
csize = (bufsize - wsize) > blocksize ? blocksize :
bufsize - wsize;
bh = ext4_getblk(handle, ea_inode, block, 0);
if (IS_ERR(bh))
return PTR_ERR(bh);
if (!bh) {
WARN_ON_ONCE(1);
EXT4_ERROR_INODE(ea_inode,
"ext4_getblk() return bh = NULL");
return -EFSCORRUPTED;
}
ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
EXT4_JTR_NONE);
if (ret)
goto out;
memcpy(bh->b_data, buf, csize);
set_buffer_uptodate(bh);
ext4_handle_dirty_metadata(handle, ea_inode, bh);
buf += csize;
wsize += csize;
block += 1;
}
inode_lock(ea_inode);
i_size_write(ea_inode, wsize);
ext4_update_i_disksize(ea_inode, wsize);
inode_unlock(ea_inode);
ret2 = ext4_mark_inode_dirty(handle, ea_inode);
if (unlikely(ret2 && !ret))
ret = ret2;
out:
brelse(bh);
return ret;
}
/*
* Create an inode to store the value of a large EA.
*/
static struct inode *ext4_xattr_inode_create(handle_t *handle,
struct inode *inode, u32 hash)
{
struct inode *ea_inode = NULL;
uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
int err;
if (inode->i_sb->s_root == NULL) {
ext4_warning(inode->i_sb,
"refuse to create EA inode when umounting");
WARN_ON(1);
return ERR_PTR(-EINVAL);
}
/*
* Let the next inode be the goal, so we try and allocate the EA inode
* in the same group, or nearby one.
*/
ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
EXT4_EA_INODE_FL);
if (!IS_ERR(ea_inode)) {
ea_inode->i_op = &ext4_file_inode_operations;
ea_inode->i_fop = &ext4_file_operations;
ext4_set_aops(ea_inode);
ext4_xattr_inode_set_class(ea_inode);
unlock_new_inode(ea_inode);
ext4_xattr_inode_set_ref(ea_inode, 1);
ext4_xattr_inode_set_hash(ea_inode, hash);
err = ext4_mark_inode_dirty(handle, ea_inode);
if (!err)
err = ext4_inode_attach_jinode(ea_inode);
if (err) {
if (ext4_xattr_inode_dec_ref(handle, ea_inode))
ext4_warning_inode(ea_inode,
"cleanup dec ref error %d", err);
iput(ea_inode);
return ERR_PTR(err);
}
/*
* Xattr inodes are shared therefore quota charging is performed
* at a higher level.
*/
dquot_free_inode(ea_inode);
dquot_drop(ea_inode);
inode_lock(ea_inode);
ea_inode->i_flags |= S_NOQUOTA;
inode_unlock(ea_inode);
}
return ea_inode;
}
static struct inode *
ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
size_t value_len, u32 hash)
{
struct inode *ea_inode;
struct mb_cache_entry *ce;
struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
void *ea_data;
if (!ea_inode_cache)
return NULL;
ce = mb_cache_entry_find_first(ea_inode_cache, hash);
if (!ce)
return NULL;
WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
!(current->flags & PF_MEMALLOC_NOFS));
ea_data = kvmalloc(value_len, GFP_KERNEL);
if (!ea_data) {
mb_cache_entry_put(ea_inode_cache, ce);
return NULL;
}
while (ce) {
ea_inode = ext4_iget(inode->i_sb, ce->e_value,
EXT4_IGET_EA_INODE);
if (IS_ERR(ea_inode))
goto next_entry;
ext4_xattr_inode_set_class(ea_inode);
if (i_size_read(ea_inode) == value_len &&
!ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
!ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
value_len) &&
!memcmp(value, ea_data, value_len)) {
mb_cache_entry_touch(ea_inode_cache, ce);
mb_cache_entry_put(ea_inode_cache, ce);
kvfree(ea_data);
return ea_inode;
}
iput(ea_inode);
next_entry:
ce = mb_cache_entry_find_next(ea_inode_cache, ce);
}
kvfree(ea_data);
return NULL;
}
/*
* Add value of the EA in an inode.
*/
static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
const void *value, size_t value_len,
struct inode **ret_inode)
{
struct inode *ea_inode;
u32 hash;
int err;
hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
if (ea_inode) {
err = ext4_xattr_inode_inc_ref(handle, ea_inode);
if (err) {
iput(ea_inode);
return err;
}
*ret_inode = ea_inode;
return 0;
}
/* Create an inode for the EA value */
ea_inode = ext4_xattr_inode_create(handle, inode, hash);
if (IS_ERR(ea_inode))
return PTR_ERR(ea_inode);
err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
if (err) {
if (ext4_xattr_inode_dec_ref(handle, ea_inode))
ext4_warning_inode(ea_inode, "cleanup dec ref error %d", err);
iput(ea_inode);
return err;
}
if (EA_INODE_CACHE(inode))
mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
ea_inode->i_ino, true /* reusable */);
*ret_inode = ea_inode;
return 0;
}
/*
* Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
* feature is enabled.
*/
#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
struct ext4_xattr_search *s,
handle_t *handle, struct inode *inode,
bool is_block)
{
struct ext4_xattr_entry *last, *next;
struct ext4_xattr_entry *here = s->here;
size_t min_offs = s->end - s->base, name_len = strlen(i->name);
int in_inode = i->in_inode;
struct inode *old_ea_inode = NULL;
struct inode *new_ea_inode = NULL;
size_t old_size, new_size;
int ret;
/* Space used by old and new values. */
old_size = (!s->not_found && !here->e_value_inum) ?
EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
/*
* Optimization for the simple case when old and new values have the
* same padded sizes. Not applicable if external inodes are involved.
*/
if (new_size && new_size == old_size) {
size_t offs = le16_to_cpu(here->e_value_offs);
void *val = s->base + offs;
here->e_value_size = cpu_to_le32(i->value_len);
if (i->value == EXT4_ZERO_XATTR_VALUE) {
memset(val, 0, new_size);
} else {
memcpy(val, i->value, i->value_len);
/* Clear padding bytes. */
memset(val + i->value_len, 0, new_size - i->value_len);
}
goto update_hash;
}
/* Compute min_offs and last. */
last = s->first;
for (; !IS_LAST_ENTRY(last); last = next) {
next = EXT4_XATTR_NEXT(last);
if ((void *)next >= s->end) {
EXT4_ERROR_INODE(inode, "corrupted xattr entries");
ret = -EFSCORRUPTED;
goto out;
}
if (!last->e_value_inum && last->e_value_size) {
size_t offs = le16_to_cpu(last->e_value_offs);
if (offs < min_offs)
min_offs = offs;
}
}
/* Check whether we have enough space. */
if (i->value) {
size_t free;
free = min_offs - ((void *)last - s->base) - sizeof(__u32);
if (!s->not_found)
free += EXT4_XATTR_LEN(name_len) + old_size;
if (free < EXT4_XATTR_LEN(name_len) + new_size) {
ret = -ENOSPC;
goto out;
}
/*
* If storing the value in an external inode is an option,
* reserve space for xattr entries/names in the external
* attribute block so that a long value does not occupy the
* whole space and prevent further entries being added.
*/
if (ext4_has_feature_ea_inode(inode->i_sb) &&
new_size && is_block &&
(min_offs + old_size - new_size) <
EXT4_XATTR_BLOCK_RESERVE(inode)) {
ret = -ENOSPC;
goto out;
}
}
/*
* Getting access to old and new ea inodes is subject to failures.
* Finish that work before doing any modifications to the xattr data.
*/
if (!s->not_found && here->e_value_inum) {
ret = ext4_xattr_inode_iget(inode,
le32_to_cpu(here->e_value_inum),
le32_to_cpu(here->e_hash),
&old_ea_inode);
if (ret) {
old_ea_inode = NULL;
goto out;
}
}
if (i->value && in_inode) {
WARN_ON_ONCE(!i->value_len);
ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
if (ret)
goto out;
ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
i->value_len,
&new_ea_inode);
if (ret) {
new_ea_inode = NULL;
ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
goto out;
}
}
if (old_ea_inode) {
/* We are ready to release ref count on the old_ea_inode. */
ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
if (ret) {
/* Release newly required ref count on new_ea_inode. */
if (new_ea_inode) {
int err;
err = ext4_xattr_inode_dec_ref(handle,
new_ea_inode);
if (err)
ext4_warning_inode(new_ea_inode,
"dec ref new_ea_inode err=%d",
err);
ext4_xattr_inode_free_quota(inode, new_ea_inode,
i->value_len);
}
goto out;
}
ext4_xattr_inode_free_quota(inode, old_ea_inode,
le32_to_cpu(here->e_value_size));
}
/* No failures allowed past this point. */
if (!s->not_found && here->e_value_size && !here->e_value_inum) {
/* Remove the old value. */
void *first_val = s->base + min_offs;
size_t offs = le16_to_cpu(here->e_value_offs);
void *val = s->base + offs;
memmove(first_val + old_size, first_val, val - first_val);
memset(first_val, 0, old_size);
min_offs += old_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_inum &&
last->e_value_size && o < offs)
last->e_value_offs = cpu_to_le16(o + old_size);
last = EXT4_XATTR_NEXT(last);
}
}
if (!i->value) {
/* Remove old name. */
size_t size = EXT4_XATTR_LEN(name_len);
last = ENTRY((void *)last - size);
memmove(here, (void *)here + size,
(void *)last - (void *)here + sizeof(__u32));
memset(last, 0, size);
} else if (s->not_found) {
/* Insert new name. */
size_t size = EXT4_XATTR_LEN(name_len);
size_t rest = (void *)last - (void *)here + sizeof(__u32);
memmove((void *)here + size, here, rest);
memset(here, 0, size);
here->e_name_index = i->name_index;
here->e_name_len = name_len;
memcpy(here->e_name, i->name, name_len);
} else {
/* This is an update, reset value info. */
here->e_value_inum = 0;
here->e_value_offs = 0;
here->e_value_size = 0;
}
if (i->value) {
/* Insert new value. */
if (in_inode) {
here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
} else if (i->value_len) {
void *val = s->base + min_offs - new_size;
here->e_value_offs = cpu_to_le16(min_offs - new_size);
if (i->value == EXT4_ZERO_XATTR_VALUE) {
memset(val, 0, new_size);
} else {
memcpy(val, i->value, i->value_len);
/* Clear padding bytes. */
memset(val + i->value_len, 0,
new_size - i->value_len);
}
}
here->e_value_size = cpu_to_le32(i->value_len);
}
update_hash:
if (i->value) {
__le32 hash = 0;
/* Entry hash calculation. */
if (in_inode) {
__le32 crc32c_hash;
/*
* Feed crc32c hash instead of the raw value for entry
* hash calculation. This is to avoid walking
* potentially long value buffer again.
*/
crc32c_hash = cpu_to_le32(
ext4_xattr_inode_get_hash(new_ea_inode));
hash = ext4_xattr_hash_entry(here->e_name,
here->e_name_len,
&crc32c_hash, 1);
} else if (is_block) {
__le32 *value = s->base + le16_to_cpu(
here->e_value_offs);
hash = ext4_xattr_hash_entry(here->e_name,
here->e_name_len, value,
new_size >> 2);
}
here->e_hash = hash;
}
if (is_block)
ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
ret = 0;
out:
iput(old_ea_inode);
iput(new_ea_inode);
return ret;
}
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 = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bs->bh)) {
error = PTR_ERR(bs->bh);
bs->bh = NULL;
return error;
}
ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
atomic_read(&(bs->bh->b_count)),
le32_to_cpu(BHDR(bs->bh)->h_refcount));
error = ext4_xattr_check_block(inode, bs->bh);
if (error)
return error;
/* 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 = xattr_find_entry(inode, &bs->s.here, bs->s.end,
i->name_index, i->name, 1);
if (error && error != -ENODATA)
return error;
bs->s.not_found = error;
}
return 0;
}
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_copy = bs->s;
struct ext4_xattr_search *s = &s_copy;
struct mb_cache_entry *ce = NULL;
int error = 0;
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
struct inode *ea_inode = NULL, *tmp_inode;
size_t old_ea_inode_quota = 0;
unsigned int ea_ino;
#define header(x) ((struct ext4_xattr_header *)(x))
if (s->base) {
int offset = (char *)s->here - bs->bh->b_data;
BUFFER_TRACE(bs->bh, "get_write_access");
error = ext4_journal_get_write_access(handle, sb, bs->bh,
EXT4_JTR_NONE);
if (error)
goto cleanup;
lock_buffer(bs->bh);
if (header(s->base)->h_refcount == cpu_to_le32(1)) {
__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
/*
* This must happen under buffer lock for
* ext4_xattr_block_set() to reliably detect modified
* block
*/
if (ea_block_cache) {
struct mb_cache_entry *oe;
oe = mb_cache_entry_delete_or_get(ea_block_cache,
hash, bs->bh->b_blocknr);
if (oe) {
/*
* Xattr block is getting reused. Leave
* it alone.
*/
mb_cache_entry_put(ea_block_cache, oe);
goto clone_block;
}
}
ea_bdebug(bs->bh, "modifying in-place");
error = ext4_xattr_set_entry(i, s, handle, inode,
true /* is_block */);
ext4_xattr_block_csum_set(inode, bs->bh);
unlock_buffer(bs->bh);
if (error == -EFSCORRUPTED)
goto bad_block;
if (!error)
error = ext4_handle_dirty_metadata(handle,
inode,
bs->bh);
if (error)
goto cleanup;
goto inserted;
}
clone_block:
unlock_buffer(bs->bh);
ea_bdebug(bs->bh, "cloning");
s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
error = -ENOMEM;
if (s->base == NULL)
goto cleanup;
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;
/*
* If existing entry points to an xattr inode, we need
* to prevent ext4_xattr_set_entry() from decrementing
* ref count on it because the reference belongs to the
* original block. In this case, make the entry look
* like it has an empty value.
*/
if (!s->not_found && s->here->e_value_inum) {
ea_ino = le32_to_cpu(s->here->e_value_inum);
error = ext4_xattr_inode_iget(inode, ea_ino,
le32_to_cpu(s->here->e_hash),
&tmp_inode);
if (error)
goto cleanup;
if (!ext4_test_inode_state(tmp_inode,
EXT4_STATE_LUSTRE_EA_INODE)) {
/*
* Defer quota free call for previous
* inode until success is guaranteed.
*/
old_ea_inode_quota = le32_to_cpu(
s->here->e_value_size);
}
iput(tmp_inode);
s->here->e_value_inum = 0;
s->here->e_value_size = 0;
}
} else {
/* Allocate a buffer where we construct the new block. */
s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
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, handle, inode, true /* is_block */);
if (error == -EFSCORRUPTED)
goto bad_block;
if (error)
goto cleanup;
if (i->value && s->here->e_value_inum) {
/*
* A ref count on ea_inode has been taken as part of the call to
* ext4_xattr_set_entry() above. We would like to drop this
* extra ref but we have to wait until the xattr block is
* initialized and has its own ref count on the ea_inode.
*/
ea_ino = le32_to_cpu(s->here->e_value_inum);
error = ext4_xattr_inode_iget(inode, ea_ino,
le32_to_cpu(s->here->e_hash),
&ea_inode);
if (error) {
ea_inode = NULL;
goto cleanup;
}
}
inserted:
if (!IS_LAST_ENTRY(s->first)) {
new_bh = ext4_xattr_block_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 {
u32 ref;
#ifdef EXT4_XATTR_DEBUG
WARN_ON_ONCE(dquot_initialize_needed(inode));
#endif
/* The old block is released after updating
the inode. */
error = dquot_alloc_block(inode,
EXT4_C2B(EXT4_SB(sb), 1));
if (error)
goto cleanup;
BUFFER_TRACE(new_bh, "get_write_access");
error = ext4_journal_get_write_access(
handle, sb, new_bh,
EXT4_JTR_NONE);
if (error)
goto cleanup_dquot;
lock_buffer(new_bh);
/*
* We have to be careful about races with
* adding references to xattr block. Once we
* hold buffer lock xattr block's state is
* stable so we can check the additional
* reference fits.
*/
ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
if (ref > EXT4_XATTR_REFCOUNT_MAX) {
/*
* Undo everything and check mbcache
* again.
*/
unlock_buffer(new_bh);
dquot_free_block(inode,
EXT4_C2B(EXT4_SB(sb),
1));
brelse(new_bh);
mb_cache_entry_put(ea_block_cache, ce);
ce = NULL;
new_bh = NULL;
goto inserted;
}
BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
if (ref == EXT4_XATTR_REFCOUNT_MAX)
clear_bit(MBE_REUSABLE_B, &ce->e_flags);
ea_bdebug(new_bh, "reusing; refcount now=%d",
ref);
ext4_xattr_block_csum_set(inode, new_bh);
unlock_buffer(new_bh);
error = ext4_handle_dirty_metadata(handle,
inode,
new_bh);
if (error)
goto cleanup_dquot;
}
mb_cache_entry_touch(ea_block_cache, ce);
mb_cache_entry_put(ea_block_cache, 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");
ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
new_bh = bs->bh;
get_bh(new_bh);
} else {
/* We need to allocate a new block */
ext4_fsblk_t goal, block;
#ifdef EXT4_XATTR_DEBUG
WARN_ON_ONCE(dquot_initialize_needed(inode));
#endif
goal = ext4_group_first_block_no(sb,
EXT4_I(inode)->i_block_group);
block = ext4_new_meta_blocks(handle, inode, goal, 0,
NULL, &error);
if (error)
goto cleanup;
ea_idebug(inode, "creating block %llu",
(unsigned long long)block);
new_bh = sb_getblk(sb, block);
if (unlikely(!new_bh)) {
error = -ENOMEM;
getblk_failed:
ext4_free_blocks(handle, inode, NULL, block, 1,
EXT4_FREE_BLOCKS_METADATA);
goto cleanup;
}
error = ext4_xattr_inode_inc_ref_all(handle, inode,
ENTRY(header(s->base)+1));
if (error)
goto getblk_failed;
if (ea_inode) {
/* Drop the extra ref on ea_inode. */
error = ext4_xattr_inode_dec_ref(handle,
ea_inode);
if (error)
ext4_warning_inode(ea_inode,
"dec ref error=%d",
error);
iput(ea_inode);
ea_inode = NULL;
}
lock_buffer(new_bh);
error = ext4_journal_get_create_access(handle, sb,
new_bh, EXT4_JTR_NONE);
if (error) {
unlock_buffer(new_bh);
error = -EIO;
goto getblk_failed;
}
memcpy(new_bh->b_data, s->base, new_bh->b_size);
ext4_xattr_block_csum_set(inode, new_bh);
set_buffer_uptodate(new_bh);
unlock_buffer(new_bh);
ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
error = ext4_handle_dirty_metadata(handle, inode,
new_bh);
if (error)
goto cleanup;
}
}
if (old_ea_inode_quota)
ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
/* 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) {
struct ext4_xattr_inode_array *ea_inode_array = NULL;
ext4_xattr_release_block(handle, inode, bs->bh,
&ea_inode_array,
0 /* extra_credits */);
ext4_xattr_inode_array_free(ea_inode_array);
}
error = 0;
cleanup:
if (ea_inode) {
int error2;
error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
if (error2)
ext4_warning_inode(ea_inode, "dec ref error=%d",
error2);
/* If there was an error, revert the quota charge. */
if (error)
ext4_xattr_inode_free_quota(inode, ea_inode,
i_size_read(ea_inode));
iput(ea_inode);
}
if (ce)
mb_cache_entry_put(ea_block_cache, ce);
brelse(new_bh);
if (!(bs->bh && s->base == bs->bh->b_data))
kfree(s->base);
return error;
cleanup_dquot:
dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
goto cleanup;
bad_block:
EXT4_ERROR_INODE(inode, "bad block %llu",
EXT4_I(inode)->i_file_acl);
goto cleanup;
#undef header
}
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_INODE_HAS_XATTR_SPACE(inode))
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_test_inode_state(inode, EXT4_STATE_XATTR)) {
error = xattr_check_inode(inode, header, is->s.end);
if (error)
return error;
/* Find the named attribute. */
error = xattr_find_entry(inode, &is->s.here, is->s.end,
i->name_index, i->name, 0);
if (error && error != -ENODATA)
return error;
is->s.not_found = error;
}
return 0;
}
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_INODE_HAS_XATTR_SPACE(inode))
return -ENOSPC;
error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
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_set_inode_state(inode, EXT4_STATE_XATTR);
} else {
header->h_magic = cpu_to_le32(0);
ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
}
return 0;
}
static int ext4_xattr_value_same(struct ext4_xattr_search *s,
struct ext4_xattr_info *i)
{
void *value;
/* When e_value_inum is set the value is stored externally. */
if (s->here->e_value_inum)
return 0;
if (le32_to_cpu(s->here->e_value_size) != i->value_len)
return 0;
value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
return !memcmp(value, i->value, i->value_len);
}
static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
{
struct buffer_head *bh;
int error;
if (!EXT4_I(inode)->i_file_acl)
return NULL;
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh))
return bh;
error = ext4_xattr_check_block(inode, bh);
if (error) {
brelse(bh);
return ERR_PTR(error);
}
return bh;
}
/*
* ext4_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
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,
.in_inode = 0,
};
struct ext4_xattr_ibody_find is = {
.s = { .not_found = -ENODATA, },
};
struct ext4_xattr_block_find bs = {
.s = { .not_found = -ENODATA, },
};
int no_expand;
int error;
if (!name)
return -EINVAL;
if (strlen(name) > 255)
return -ERANGE;
ext4_write_lock_xattr(inode, &no_expand);
/* Check journal credits under write lock. */
if (ext4_handle_valid(handle)) {
struct buffer_head *bh;
int credits;
bh = ext4_xattr_get_block(inode);
if (IS_ERR(bh)) {
error = PTR_ERR(bh);
goto cleanup;
}
credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
value_len,
flags & XATTR_CREATE);
brelse(bh);
if (jbd2_handle_buffer_credits(handle) < credits) {
error = -ENOSPC;
goto cleanup;
}
WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
}
error = ext4_reserve_inode_write(handle, inode, &is.iloc);
if (error)
goto cleanup;
if (ext4_test_inode_state(inode, 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_clear_inode_state(inode, 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 = 0;
/* Xattr value did not change? Save us some work and bail out */
if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
goto cleanup;
if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
goto cleanup;
if (ext4_has_feature_ea_inode(inode->i_sb) &&
(EXT4_XATTR_SIZE(i.value_len) >
EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
i.in_inode = 1;
retry_inode:
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) {
brelse(bs.bh);
bs.bh = NULL;
error = ext4_xattr_block_find(inode, &i, &bs);
if (error)
goto cleanup;
}
error = ext4_xattr_block_set(handle, inode, &i, &bs);
if (!error && !is.s.not_found) {
i.value = NULL;
error = ext4_xattr_ibody_set(handle, inode, &i,
&is);
} else if (error == -ENOSPC) {
/*
* Xattr does not fit in the block, store at
* external inode if possible.
*/
if (ext4_has_feature_ea_inode(inode->i_sb) &&
i.value_len && !i.in_inode) {
i.in_inode = 1;
goto retry_inode;
}
}
}
}
if (!error) {
ext4_xattr_update_super_block(handle, inode->i_sb);
inode->i_ctime = current_time(inode);
inode_inc_iversion(inode);
if (!value)
no_expand = 0;
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);
}
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
cleanup:
brelse(is.iloc.bh);
brelse(bs.bh);
ext4_write_unlock_xattr(inode, &no_expand);
return error;
}
int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
bool is_create, int *credits)
{
struct buffer_head *bh;
int err;
*credits = 0;
if (!EXT4_SB(inode->i_sb)->s_journal)
return 0;
down_read(&EXT4_I(inode)->xattr_sem);
bh = ext4_xattr_get_block(inode);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
} else {
*credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
value_len, is_create);
brelse(bh);
err = 0;
}
up_read(&EXT4_I(inode)->xattr_sem);
return err;
}
/*
* 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;
struct super_block *sb = inode->i_sb;
int error, retries = 0;
int credits;
error = dquot_initialize(inode);
if (error)
return error;
retry:
error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
&credits);
if (error)
return error;
handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
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(sb, &retries))
goto retry;
if (error == 0)
error = error2;
}
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
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)
{
struct ext4_xattr_entry *last = entry;
int new_offs;
/* We always shift xattr headers further thus offsets get lower */
BUG_ON(value_offs_shift > 0);
/* Adjust the value offsets of the entries */
for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
if (!last->e_value_inum && last->e_value_size) {
new_offs = le16_to_cpu(last->e_value_offs) +
value_offs_shift;
last->e_value_offs = cpu_to_le16(new_offs);
}
}
/* Shift the entries by n bytes */
memmove(to, from, n);
}
/*
* Move xattr pointed to by 'entry' from inode into external xattr block
*/
static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
struct ext4_inode *raw_inode,
struct ext4_xattr_entry *entry)
{
struct ext4_xattr_ibody_find *is = NULL;
struct ext4_xattr_block_find *bs = NULL;
char *buffer = NULL, *b_entry_name = NULL;
size_t value_size = le32_to_cpu(entry->e_value_size);
struct ext4_xattr_info i = {
.value = NULL,
.value_len = 0,
.name_index = entry->e_name_index,
.in_inode = !!entry->e_value_inum,
};
struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
int needs_kvfree = 0;
int error;
is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
if (!is || !bs || !b_entry_name) {
error = -ENOMEM;
goto out;
}
is->s.not_found = -ENODATA;
bs->s.not_found = -ENODATA;
is->iloc.bh = NULL;
bs->bh = NULL;
/* Save the entry name and the entry value */
if (entry->e_value_inum) {
buffer = kvmalloc(value_size, GFP_NOFS);
if (!buffer) {
error = -ENOMEM;
goto out;
}
needs_kvfree = 1;
error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
if (error)
goto out;
} else {
size_t value_offs = le16_to_cpu(entry->e_value_offs);
buffer = (void *)IFIRST(header) + value_offs;
}
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 out;
error = ext4_xattr_ibody_find(inode, &i, is);
if (error)
goto out;
i.value = buffer;
i.value_len = value_size;
error = ext4_xattr_block_find(inode, &i, bs);
if (error)
goto out;
/* Move ea entry from the inode into the block */
error = ext4_xattr_block_set(handle, inode, &i, bs);
if (error)
goto out;
/* Remove the chosen entry from the inode */
i.value = NULL;
i.value_len = 0;
error = ext4_xattr_ibody_set(handle, inode, &i, is);
out:
kfree(b_entry_name);
if (needs_kvfree && buffer)
kvfree(buffer);
if (is)
brelse(is->iloc.bh);
if (bs)
brelse(bs->bh);
kfree(is);
kfree(bs);
return error;
}
static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
struct ext4_inode *raw_inode,
int isize_diff, size_t ifree,
size_t bfree, int *total_ino)
{
struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
struct ext4_xattr_entry *small_entry;
struct ext4_xattr_entry *entry;
struct ext4_xattr_entry *last;
unsigned int entry_size; /* EA entry size */
unsigned int total_size; /* EA entry size + value size */
unsigned int min_total_size;
int error;
while (isize_diff > ifree) {
entry = NULL;
small_entry = NULL;
min_total_size = ~0U;
last = IFIRST(header);
/* Find the entry best suited to be pushed into EA block */
for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
/* never move system.data out of the inode */
if ((last->e_name_len == 4) &&
(last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
!memcmp(last->e_name, "data", 4))
continue;
total_size = EXT4_XATTR_LEN(last->e_name_len);
if (!last->e_value_inum)
total_size += EXT4_XATTR_SIZE(
le32_to_cpu(last->e_value_size));
if (total_size <= bfree &&
total_size < min_total_size) {
if (total_size + ifree < isize_diff) {
small_entry = last;
} else {
entry = last;
min_total_size = total_size;
}
}
}
if (entry == NULL) {
if (small_entry == NULL)
return -ENOSPC;
entry = small_entry;
}
entry_size = EXT4_XATTR_LEN(entry->e_name_len);
total_size = entry_size;
if (!entry->e_value_inum)
total_size += EXT4_XATTR_SIZE(
le32_to_cpu(entry->e_value_size));
error = ext4_xattr_move_to_block(handle, inode, raw_inode,
entry);
if (error)
return error;
*total_ino -= entry_size;
ifree += total_size;
bfree -= total_size;
}
return 0;
}
/*
* 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_sb_info *sbi = EXT4_SB(inode->i_sb);
static unsigned int mnt_count;
size_t min_offs;
size_t ifree, bfree;
int total_ino;
void *base, *end;
int error = 0, tried_min_extra_isize = 0;
int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
int isize_diff; /* How much do we need to grow i_extra_isize */
retry:
isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
return 0;
header = IHDR(inode, raw_inode);
/*
* Check if enough free space is available in the inode to shift the
* entries ahead by new_extra_isize.
*/
base = IFIRST(header);
end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
min_offs = end - base;
total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
error = xattr_check_inode(inode, header, end);
if (error)
goto cleanup;
ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
if (ifree >= isize_diff)
goto shift;
/*
* 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) {
struct buffer_head *bh;
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh)) {
error = PTR_ERR(bh);
goto cleanup;
}
error = ext4_xattr_check_block(inode, bh);
if (error) {
brelse(bh);
goto cleanup;
}
base = BHDR(bh);
end = bh->b_data + bh->b_size;
min_offs = end - base;
bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
NULL);
brelse(bh);
if (bfree + ifree < isize_diff) {
if (!tried_min_extra_isize && s_min_extra_isize) {
tried_min_extra_isize++;
new_extra_isize = s_min_extra_isize;
goto retry;
}
error = -ENOSPC;
goto cleanup;
}
} else {
bfree = inode->i_sb->s_blocksize;
}
error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
isize_diff, ifree, bfree,
&total_ino);
if (error) {
if (error == -ENOSPC && !tried_min_extra_isize &&
s_min_extra_isize) {
tried_min_extra_isize++;
new_extra_isize = s_min_extra_isize;
goto retry;
}
goto cleanup;
}
shift:
/* Adjust the offsets and shift the remaining entries ahead */
ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
- new_extra_isize, (void *)raw_inode +
EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
(void *)header, total_ino);
EXT4_I(inode)->i_extra_isize = new_extra_isize;
if (ext4_has_inline_data(inode))
error = ext4_find_inline_data_nolock(inode);
cleanup:
if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
inode->i_ino);
mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
}
return error;
}
#define EIA_INCR 16 /* must be 2^n */
#define EIA_MASK (EIA_INCR - 1)
/* Add the large xattr @inode into @ea_inode_array for deferred iput().
* If @ea_inode_array is new or full it will be grown and the old
* contents copied over.
*/
static int
ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
struct inode *inode)
{
if (*ea_inode_array == NULL) {
/*
* Start with 15 inodes, so it fits into a power-of-two size.
* If *ea_inode_array is NULL, this is essentially offsetof()
*/
(*ea_inode_array) =
kmalloc(offsetof(struct ext4_xattr_inode_array,
inodes[EIA_MASK]),
GFP_NOFS);
if (*ea_inode_array == NULL)
return -ENOMEM;
(*ea_inode_array)->count = 0;
} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
/* expand the array once all 15 + n * 16 slots are full */
struct ext4_xattr_inode_array *new_array = NULL;
int count = (*ea_inode_array)->count;
/* if new_array is NULL, this is essentially offsetof() */
new_array = kmalloc(
offsetof(struct ext4_xattr_inode_array,
inodes[count + EIA_INCR]),
GFP_NOFS);
if (new_array == NULL)
return -ENOMEM;
memcpy(new_array, *ea_inode_array,
offsetof(struct ext4_xattr_inode_array, inodes[count]));
kfree(*ea_inode_array);
*ea_inode_array = new_array;
}
(*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
return 0;
}
/*
* ext4_xattr_delete_inode()
*
* Free extended attribute resources associated with this inode. Traverse
* all entries and decrement reference on any xattr inodes associated with this
* inode. This is called immediately before an inode is freed. We have exclusive
* access to the inode. If an orphan inode is deleted it will also release its
* references on xattr block and xattr inodes.
*/
int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
struct ext4_xattr_inode_array **ea_inode_array,
int extra_credits)
{
struct buffer_head *bh = NULL;
struct ext4_xattr_ibody_header *header;
struct ext4_iloc iloc = { .bh = NULL };
struct ext4_xattr_entry *entry;
struct inode *ea_inode;
int error;
error = ext4_journal_ensure_credits(handle, extra_credits,
ext4_free_metadata_revoke_credits(inode->i_sb, 1));
if (error < 0) {
EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
goto cleanup;
}
if (ext4_has_feature_ea_inode(inode->i_sb) &&
ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
error = ext4_get_inode_loc(inode, &iloc);
if (error) {
EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
goto cleanup;
}
error = ext4_journal_get_write_access(handle, inode->i_sb,
iloc.bh, EXT4_JTR_NONE);
if (error) {
EXT4_ERROR_INODE(inode, "write access (error %d)",
error);
goto cleanup;
}
header = IHDR(inode, ext4_raw_inode(&iloc));
if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
IFIRST(header),
false /* block_csum */,
ea_inode_array,
extra_credits,
false /* skip_quota */);
}
if (EXT4_I(inode)->i_file_acl) {
bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
if (IS_ERR(bh)) {
error = PTR_ERR(bh);
if (error == -EIO) {
EXT4_ERROR_INODE_ERR(inode, EIO,
"block %llu read error",
EXT4_I(inode)->i_file_acl);
}
bh = NULL;
goto cleanup;
}
error = ext4_xattr_check_block(inode, bh);
if (error)
goto cleanup;
if (ext4_has_feature_ea_inode(inode->i_sb)) {
for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
entry = EXT4_XATTR_NEXT(entry)) {
if (!entry->e_value_inum)
continue;
error = ext4_xattr_inode_iget(inode,
le32_to_cpu(entry->e_value_inum),
le32_to_cpu(entry->e_hash),
&ea_inode);
if (error)
continue;
ext4_xattr_inode_free_quota(inode, ea_inode,
le32_to_cpu(entry->e_value_size));
iput(ea_inode);
}
}
ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
extra_credits);
/*
* Update i_file_acl value in the same transaction that releases
* block.
*/
EXT4_I(inode)->i_file_acl = 0;
error = ext4_mark_inode_dirty(handle, inode);
if (error) {
EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
error);
goto cleanup;
}
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
}
error = 0;
cleanup:
brelse(iloc.bh);
brelse(bh);
return error;
}
void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
{
int idx;
if (ea_inode_array == NULL)
return;
for (idx = 0; idx < ea_inode_array->count; ++idx)
iput(ea_inode_array->inodes[idx]);
kfree(ea_inode_array);
}
/*
* ext4_xattr_block_cache_insert()
*
* Create a new entry in the extended attribute block 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_block_cache_insert(struct mb_cache *ea_block_cache,
struct buffer_head *bh)
{
struct ext4_xattr_header *header = BHDR(bh);
__u32 hash = le32_to_cpu(header->h_hash);
int reusable = le32_to_cpu(header->h_refcount) <
EXT4_XATTR_REFCOUNT_MAX;
int error;
if (!ea_block_cache)
return;
error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
bh->b_blocknr, reusable);
if (error) {
if (error == -EBUSY)
ea_bdebug(bh, "already in cache");
} else
ea_bdebug(bh, "inserting [%x]", (int)hash);
}
/*
* 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 ||
entry1->e_value_inum != entry2->e_value_inum ||
memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
return 1;
if (!entry1->e_value_inum &&
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_block_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_block_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;
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
if (!ea_block_cache)
return NULL;
if (!header->h_hash)
return NULL; /* never share */
ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
ce = mb_cache_entry_find_first(ea_block_cache, hash);
while (ce) {
struct buffer_head *bh;
bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
if (IS_ERR(bh)) {
if (PTR_ERR(bh) == -ENOMEM)
return NULL;
bh = NULL;
EXT4_ERROR_INODE(inode, "block %lu read error",
(unsigned long)ce->e_value);
} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
*pce = ce;
return bh;
}
brelse(bh);
ce = mb_cache_entry_find_next(ea_block_cache, ce);
}
return NULL;
}
#define NAME_HASH_SHIFT 5
#define VALUE_HASH_SHIFT 16
/*
* ext4_xattr_hash_entry()
*
* Compute the hash of an extended attribute.
*/
static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
size_t value_count)
{
__u32 hash = 0;
while (name_len--) {
hash = (hash << NAME_HASH_SHIFT) ^
(hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
(unsigned char)*name++;
}
while (value_count--) {
hash = (hash << VALUE_HASH_SHIFT) ^
(hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
le32_to_cpu(*value++);
}
return cpu_to_le32(hash);
}
/*
* ext4_xattr_hash_entry_signed()
*
* Compute the hash of an extended attribute incorrectly.
*/
static __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value, size_t value_count)
{
__u32 hash = 0;
while (name_len--) {
hash = (hash << NAME_HASH_SHIFT) ^
(hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
(signed char)*name++;
}
while (value_count--) {
hash = (hash << VALUE_HASH_SHIFT) ^
(hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
le32_to_cpu(*value++);
}
return 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 *here;
__u32 hash = 0;
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
#define HASH_BUCKET_BITS 10
struct mb_cache *
ext4_xattr_create_cache(void)
{
return mb_cache_create(HASH_BUCKET_BITS);
}
void ext4_xattr_destroy_cache(struct mb_cache *cache)
{
if (cache)
mb_cache_destroy(cache);
}
Reference in New Issue View Git Blame Copy Permalink