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linux/fs/ext4/xattr.c
Linus Torvalds 854f0912f8 ext4: make xattr char unsignedness in hash explicit 
Commit f3bbac3247 ("ext4: deal with legacy signed xattr name hash
values") added a hashing function for the legacy case of having the
xattr hash calculated using a signed 'char' type.  It left the unsigned
case alone, since it's all implicitly handled by the '-funsigned-char'
compiler option.

However, there's been some noise about back-porting it all into stable
kernels that lack the '-funsigned-char', so let's just make that at
least possible by making the whole 'this uses unsigned char' very
explicit in the code itself.  Whether such a back-port is really
warranted or not, I'll leave to others, but at least together with this
change it is technically sensible.

Also, add a 'pr_warn_once()' for reporting the "hey, signedness for this
hash calculation has changed" issue.  Hopefully it never triggers except
for that xfstests generic/454 test-case, but even if it does it's just
good information to have.

If for no other reason than "we can remove the legacy signed hash code
entirely if nobody ever sees the message any more".

Cc: Sasha Levin <sashal@kernel.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Theodore Ts'o <tytso@mit.edu>,
Cc: Jason Donenfeld <Jason@zx2c4.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-01-24 12:38:45 -08:00

3178 lines
83 KiB
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// 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)
{
lockdep_set_subclass(&ea_inode->i_rwsem, 1);
}
#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
ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
void *value_start)
{
struct ext4_xattr_entry *e = entry;
/* 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)
return -EFSCORRUPTED;
if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
return -EFSCORRUPTED;
e = next;
}
/* Check the values */
while (!IS_LAST_ENTRY(entry)) {
u32 size = le32_to_cpu(entry->e_value_size);
if (size > EXT4_XATTR_SIZE_MAX)
return -EFSCORRUPTED;
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)
return -EFSCORRUPTED;
value = value_start + offs;
if (value < (void *)e + sizeof(u32) ||
size > end - value ||
EXT4_XATTR_SIZE(size) > end - value)
return -EFSCORRUPTED;
}
entry = EXT4_XATTR_NEXT(entry);
}
return 0;
}
static inline int
__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
const char *function, unsigned int line)
{
int error = -EFSCORRUPTED;
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
goto errout;
if (buffer_verified(bh))
return 0;
error = -EFSBADCRC;
if (!ext4_xattr_block_csum_verify(inode, bh))
goto errout;
error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
bh->b_data);
errout:
if (error)
__ext4_error_inode(inode, function, line, 0, -error,
"corrupted xattr block %llu",
(unsigned long long) bh->b_blocknr);
else
set_buffer_verified(bh);
return error;
}
#define ext4_xattr_check_block(inode, bh) \
__ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
static int
__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
void *end, const char *function, unsigned int line)
{
int error = -EFSCORRUPTED;
if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
(header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
goto errout;
error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
errout:
if (error)
__ext4_error_inode(inode, function, line, 0, -error,
"corrupted in-inode xattr");
return error;
}
#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;
inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
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;
}
if (is_bad_inode(inode)) {
ext4_error(parent->i_sb,
"error while reading EA inode %lu is_bad_inode",
ea_ino);
err = -EIO;
goto error;
}
if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
ext4_error(parent->i_sb,
"EA inode %lu does not have EXT4_EA_INODE_FL flag",
ea_ino);
err = -EINVAL;
goto error;
}
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;
error:
iput(inode);
return err;
}
/* 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;
/*
* 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_NORMAL);
if (!IS_ERR(ea_inode) &&
!is_bad_inode(ea_inode) &&
(EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
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;
}
if (!IS_ERR(ea_inode))
iput(ea_inode);
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;
WARN_ON_ONCE(dquot_initialize_needed(inode));
/* 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;
WARN_ON_ONCE(dquot_initialize_needed(inode));
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 error;
is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
buffer = kvmalloc(value_size, GFP_NOFS);
b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
if (!is || !bs || !buffer || !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) {
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);
memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
}
memcpy(b_entry_name, entry->e_name, entry->e_name_len);
b_entry_name[entry->e_name_len] = '\0';
i.name = b_entry_name;
error = ext4_get_inode_loc(inode, &is->iloc);
if (error)
goto out;
error = ext4_xattr_ibody_find(inode, &i, is);
if (error)
goto out;
/* Remove the chosen entry from the inode */
error = ext4_xattr_ibody_set(handle, 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;
/* Add entry which was removed from the inode into the block */
error = ext4_xattr_block_set(handle, inode, &i, bs);
if (error)
goto out;
error = 0;
out:
kfree(b_entry_name);
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;
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);
}
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