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staging: erofs: introduce xattr & acl support 

This implements xattr and acl functionalities.

Inline and shared xattrs are introduced for flexibility.
Specifically, if the same xattr occurs for many times
in a large number of inodes or the value of a xattr is so large
that it isn't suitable to be inlined, a shared xattr
kept in the xattr meta will be used instead.

Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2018-07-26 20:21:52 +08:00 committed by Greg Kroah-Hartman
parent fd68c6a20f
commit b17500a0fd
8 changed files with 835 additions and 1 deletions
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37
drivers/staging/erofs/Kconfig
View File

@ -26,6 +26,43 @@ config EROFS_FS_DEBUG
For daily use, say N.
config EROFS_FS_XATTR
bool "EROFS extended attributes"
depends on EROFS_FS
default y
help
Extended attributes are name:value pairs associated with inodes by
the kernel or by users (see the attr(5) manual page, or visit
<http://acl.bestbits.at/> for details).
If unsure, say N.
config EROFS_FS_POSIX_ACL
bool "EROFS Access Control Lists"
depends on EROFS_FS_XATTR
select FS_POSIX_ACL
default y
help
Posix Access Control Lists (ACLs) support permissions for users and
groups beyond the owner/group/world scheme.
To learn more about Access Control Lists, visit the POSIX ACLs for
Linux website <http://acl.bestbits.at/>.
If you don't know what Access Control Lists are, say N.
config EROFS_FS_SECURITY
bool "EROFS Security Labels"
depends on EROFS_FS_XATTR
help
Security labels provide an access control facility to support Linux
Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
Linux. This option enables an extended attribute handler for file
security labels in the erofs filesystem, so that it requires enabling
the extended attribute support in advance.
If you are not using a security module, say N.
config EROFS_FS_USE_VM_MAP_RAM
bool "EROFS VM_MAP_RAM Support"
depends on EROFS_FS

1
drivers/staging/erofs/Makefile
View File

@ -8,4 +8,5 @@ obj-$(CONFIG_EROFS_FS) += erofs.o
# staging requirement: to be self-contained in its own directory
ccflags-y += -I$(src)/include
erofs-objs := super.o inode.o data.o namei.o dir.o
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o

33
drivers/staging/erofs/inode.c
View File

@ -10,7 +10,7 @@
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#include "internal.h"
#include "xattr.h"
/* no locking */
static int read_inode(struct inode *inode, void *data)
@ -152,15 +152,26 @@ static int fill_inode(struct inode *inode, int isdir)
if (!err) {
/* setup the new inode */
if (S_ISREG(inode->i_mode)) {
#ifdef CONFIG_EROFS_FS_XATTR
if (vi->xattr_isize)
inode->i_op = &erofs_generic_xattr_iops;
#endif
inode->i_fop = &generic_ro_fops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op =
#ifdef CONFIG_EROFS_FS_XATTR
vi->xattr_isize ? &erofs_dir_xattr_iops :
#endif
&erofs_dir_iops;
inode->i_fop = &erofs_dir_fops;
} else if (S_ISLNK(inode->i_mode)) {
/* by default, page_get_link is used for symlink */
inode->i_op =
#ifdef CONFIG_EROFS_FS_XATTR
&erofs_symlink_xattr_iops,
#else
&page_symlink_inode_operations;
#endif
inode_nohighmem(inode);
} else {
err = -EIO;
@ -208,3 +219,23 @@ struct inode *erofs_iget(struct super_block *sb,
return inode;
}
#ifdef CONFIG_EROFS_FS_XATTR
const struct inode_operations erofs_generic_xattr_iops = {
.listxattr = erofs_listxattr,
};
#endif
#ifdef CONFIG_EROFS_FS_XATTR
const struct inode_operations erofs_symlink_xattr_iops = {
.get_link = page_get_link,
.listxattr = erofs_listxattr,
};
#endif
#ifdef CONFIG_EROFS_FS_XATTR
const struct inode_operations erofs_fast_symlink_xattr_iops = {
.get_link = simple_get_link,
.listxattr = erofs_listxattr,
};
#endif

22
drivers/staging/erofs/internal.h
View File

@ -50,6 +50,9 @@ typedef u64 erofs_nid_t;
struct erofs_sb_info {
u32 blocks;
u32 meta_blkaddr;
#ifdef CONFIG_EROFS_FS_XATTR
u32 xattr_blkaddr;
#endif
/* inode slot unit size in bit shift */
unsigned char islotbits;
@ -72,6 +75,10 @@ struct erofs_sb_info {
#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
#define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
/* Mount flags set via mount options or defaults */
#define EROFS_MOUNT_XATTR_USER 0x00000010
#define EROFS_MOUNT_POSIX_ACL 0x00000020
#define clear_opt(sbi, option) ((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
#define set_opt(sbi, option) ((sbi)->mount_opt |= EROFS_MOUNT_##option)
#define test_opt(sbi, option) ((sbi)->mount_opt & EROFS_MOUNT_##option)
@ -237,17 +244,32 @@ int erofs_namei(struct inode *dir, struct qstr *name,
erofs_nid_t *nid, unsigned *d_type);
/* xattr.c */
#ifdef CONFIG_EROFS_FS_XATTR
extern const struct xattr_handler *erofs_xattr_handlers[];
#endif
/* symlink */
#ifdef CONFIG_EROFS_FS_XATTR
extern const struct inode_operations erofs_symlink_xattr_iops;
extern const struct inode_operations erofs_fast_symlink_xattr_iops;
#endif
static inline void set_inode_fast_symlink(struct inode *inode)
{
#ifdef CONFIG_EROFS_FS_XATTR
inode->i_op = &erofs_fast_symlink_xattr_iops;
#else
inode->i_op = &simple_symlink_inode_operations;
#endif
}
static inline bool is_inode_fast_symlink(struct inode *inode)
{
#ifdef CONFIG_EROFS_FS_XATTR
return inode->i_op == &erofs_fast_symlink_xattr_iops;
#else
return inode->i_op == &simple_symlink_inode_operations;
#endif
}
static inline void *erofs_vmap(struct page **pages, unsigned int count)

4
drivers/staging/erofs/namei.c
View File

@ -11,6 +11,7 @@
* distribution for more details.
*/
#include "internal.h"
#include "xattr.h"
/* based on the value of qn->len is accurate */
static inline int dirnamecmp(struct qstr *qn,
@ -239,5 +240,8 @@ const struct inode_operations erofs_dir_iops = {
const struct inode_operations erofs_dir_xattr_iops = {
.lookup = erofs_lookup,
#ifdef CONFIG_EROFS_FS_XATTR
.listxattr = erofs_listxattr,
#endif
};

67
drivers/staging/erofs/super.c
View File

@ -14,6 +14,7 @@
#include <linux/buffer_head.h>
#include <linux/statfs.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include "internal.h"
static struct kmem_cache *erofs_inode_cachep __read_mostly;
@ -107,6 +108,9 @@ static int superblock_read(struct super_block *sb)
sbi->blocks = le32_to_cpu(layout->blocks);
sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
#ifdef CONFIG_EROFS_FS_XATTR
sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
#endif
sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
sbi->root_nid = le16_to_cpu(layout->root_nid);
@ -127,13 +131,28 @@ static int superblock_read(struct super_block *sb)
static void default_options(struct erofs_sb_info *sbi)
{
#ifdef CONFIG_EROFS_FS_XATTR
set_opt(sbi, XATTR_USER);
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
set_opt(sbi, POSIX_ACL);
#endif
}
enum {
Opt_user_xattr,
Opt_nouser_xattr,
Opt_acl,
Opt_noacl,
Opt_err
};
static match_table_t erofs_tokens = {
{Opt_user_xattr, "user_xattr"},
{Opt_nouser_xattr, "nouser_xattr"},
{Opt_acl, "acl"},
{Opt_noacl, "noacl"},
{Opt_err, NULL}
};
@ -155,6 +174,36 @@ static int parse_options(struct super_block *sb, char *options)
token = match_token(p, erofs_tokens, args);
switch (token) {
#ifdef CONFIG_EROFS_FS_XATTR
case Opt_user_xattr:
set_opt(EROFS_SB(sb), XATTR_USER);
break;
case Opt_nouser_xattr:
clear_opt(EROFS_SB(sb), XATTR_USER);
break;
#else
case Opt_user_xattr:
infoln("user_xattr options not supported");
break;
case Opt_nouser_xattr:
infoln("nouser_xattr options not supported");
break;
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
case Opt_acl:
set_opt(EROFS_SB(sb), POSIX_ACL);
break;
case Opt_noacl:
clear_opt(EROFS_SB(sb), POSIX_ACL);
break;
#else
case Opt_acl:
infoln("acl options not supported");
break;
case Opt_noacl:
infoln("noacl options not supported");
break;
#endif
default:
errln("Unrecognized mount option \"%s\" "
"or missing value", p);
@ -197,6 +246,10 @@ static int erofs_read_super(struct super_block *sb,
sb->s_op = &erofs_sops;
#ifdef CONFIG_EROFS_FS_XATTR
sb->s_xattr = erofs_xattr_handlers;
#endif
/* set erofs default mount options */
default_options(sbi);
@ -386,6 +439,20 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
static int erofs_show_options(struct seq_file *seq, struct dentry *root)
{
struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
#ifdef CONFIG_EROFS_FS_XATTR
if (test_opt(sbi, XATTR_USER))
seq_puts(seq, ",user_xattr");
else
seq_puts(seq, ",nouser_xattr");
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
if (test_opt(sbi, POSIX_ACL))
seq_puts(seq, ",acl");
else
seq_puts(seq, ",noacl");
#endif
return 0;
}

579
drivers/staging/erofs/xattr.c Normal file
View File

@ -0,0 +1,579 @@
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/staging/erofs/xattr.c
*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#include <linux/security.h>
#include "xattr.h"
struct xattr_iter {
struct super_block *sb;
struct page *page;
void *kaddr;
erofs_blk_t blkaddr;
unsigned ofs;
};
static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
{
/* only init_inode_xattrs use non-atomic once */
if (unlikely(!atomic))
kunmap(it->page);
else
kunmap_atomic(it->kaddr);
unlock_page(it->page);
put_page(it->page);
}
static void init_inode_xattrs(struct inode *inode)
{
struct xattr_iter it;
unsigned i;
struct erofs_xattr_ibody_header *ih;
struct erofs_sb_info *sbi;
struct erofs_vnode *vi;
bool atomic_map;
if (likely(inode_has_inited_xattr(inode)))
return;
vi = EROFS_V(inode);
BUG_ON(!vi->xattr_isize);
sbi = EROFS_I_SB(inode);
it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
it.page = erofs_get_inline_page(inode, it.blkaddr);
BUG_ON(IS_ERR(it.page));
/* read in shared xattr array (non-atomic, see kmalloc below) */
it.kaddr = kmap(it.page);
atomic_map = false;
ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
vi->xattr_shared_count = ih->h_shared_count;
vi->xattr_shared_xattrs = (unsigned *)kmalloc_array(
vi->xattr_shared_count, sizeof(unsigned),
GFP_KERNEL | __GFP_NOFAIL);
/* let's skip ibody header */
it.ofs += sizeof(struct erofs_xattr_ibody_header);
for (i = 0; i < vi->xattr_shared_count; ++i) {
if (unlikely(it.ofs >= EROFS_BLKSIZ)) {
/* cannot be unaligned */
BUG_ON(it.ofs != EROFS_BLKSIZ);
xattr_iter_end(&it, atomic_map);
it.page = erofs_get_meta_page(inode->i_sb,
++it.blkaddr, S_ISDIR(inode->i_mode));
BUG_ON(IS_ERR(it.page));
it.kaddr = kmap_atomic(it.page);
atomic_map = true;
it.ofs = 0;
}
vi->xattr_shared_xattrs[i] =
le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
it.ofs += sizeof(__le32);
}
xattr_iter_end(&it, atomic_map);
inode_set_inited_xattr(inode);
}
struct xattr_iter_handlers {
int (*entry)(struct xattr_iter *, struct erofs_xattr_entry *);
int (*name)(struct xattr_iter *, unsigned, char *, unsigned);
int (*alloc_buffer)(struct xattr_iter *, unsigned);
void (*value)(struct xattr_iter *, unsigned, char *, unsigned);
};
static void xattr_iter_fixup(struct xattr_iter *it)
{
if (unlikely(it->ofs >= EROFS_BLKSIZ)) {
xattr_iter_end(it, true);
it->blkaddr += erofs_blknr(it->ofs);
it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
BUG_ON(IS_ERR(it->page));
it->kaddr = kmap_atomic(it->page);
it->ofs = erofs_blkoff(it->ofs);
}
}
static int inline_xattr_iter_begin(struct xattr_iter *it,
struct inode *inode)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
unsigned xattr_header_sz, inline_xattr_ofs;
xattr_header_sz = inlinexattr_header_size(inode);
if (unlikely(xattr_header_sz >= vi->xattr_isize)) {
BUG_ON(xattr_header_sz > vi->xattr_isize);
return -ENOATTR;
}
inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
it->page = erofs_get_inline_page(inode, it->blkaddr);
BUG_ON(IS_ERR(it->page));
it->kaddr = kmap_atomic(it->page);
return vi->xattr_isize - xattr_header_sz;
}
static int xattr_foreach(struct xattr_iter *it,
struct xattr_iter_handlers *op, unsigned *tlimit)
{
struct erofs_xattr_entry entry;
unsigned value_sz, processed, slice;
int err;
/* 0. fixup blkaddr, ofs, ipage */
xattr_iter_fixup(it);
/*
* 1. read xattr entry to the memory,
* since we do EROFS_XATTR_ALIGN
* therefore entry should be in the page
*/
entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
if (tlimit != NULL) {
unsigned entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
BUG_ON(*tlimit < entry_sz);
*tlimit -= entry_sz;
}
it->ofs += sizeof(struct erofs_xattr_entry);
value_sz = le16_to_cpu(entry.e_value_size);
/* handle entry */
err = op->entry(it, &entry);
if (err) {
it->ofs += entry.e_name_len + value_sz;
goto out;
}
/* 2. handle xattr name (ofs will finally be at the end of name) */
processed = 0;
while (processed < entry.e_name_len) {
if (it->ofs >= EROFS_BLKSIZ) {
BUG_ON(it->ofs > EROFS_BLKSIZ);
xattr_iter_fixup(it);
it->ofs = 0;
}
slice = min_t(unsigned, PAGE_SIZE - it->ofs,
entry.e_name_len - processed);
/* handle name */
err = op->name(it, processed, it->kaddr + it->ofs, slice);
if (err) {
it->ofs += entry.e_name_len - processed + value_sz;
goto out;
}
it->ofs += slice;
processed += slice;
}
/* 3. handle xattr value */
processed = 0;
if (op->alloc_buffer != NULL) {
err = op->alloc_buffer(it, value_sz);
if (err) {
it->ofs += value_sz;
goto out;
}
}
while (processed < value_sz) {
if (it->ofs >= EROFS_BLKSIZ) {
BUG_ON(it->ofs > EROFS_BLKSIZ);
xattr_iter_fixup(it);
it->ofs = 0;
}
slice = min_t(unsigned, PAGE_SIZE - it->ofs,
value_sz - processed);
op->value(it, processed, it->kaddr + it->ofs, slice);
it->ofs += slice;
processed += slice;
}
out:
/* we assume that ofs is aligned with 4 bytes */
it->ofs = EROFS_XATTR_ALIGN(it->ofs);
return err;
}
struct getxattr_iter {
struct xattr_iter it;
char *buffer;
int buffer_size, index;
struct qstr name;
};
static int xattr_entrymatch(struct xattr_iter *_it,
struct erofs_xattr_entry *entry)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
return (it->index != entry->e_name_index ||
it->name.len != entry->e_name_len) ? -ENOATTR : 0;
}
static int xattr_namematch(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
}
static int xattr_checkbuffer(struct xattr_iter *_it,
unsigned value_sz)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
int err = it->buffer_size < value_sz ? -ERANGE : 0;
it->buffer_size = value_sz;
return it->buffer == NULL ? 1 : err;
}
static void xattr_copyvalue(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
memcpy(it->buffer + processed, buf, len);
}
static struct xattr_iter_handlers find_xattr_handlers = {
.entry = xattr_entrymatch,
.name = xattr_namematch,
.alloc_buffer = xattr_checkbuffer,
.value = xattr_copyvalue
};
static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
{
int ret;
unsigned remaining;
ret = inline_xattr_iter_begin(&it->it, inode);
if (ret < 0)
return ret;
remaining = ret;
while (remaining) {
if ((ret = xattr_foreach(&it->it,
&find_xattr_handlers, &remaining)) >= 0)
break;
}
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_size;
}
static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
unsigned i;
int ret = -ENOATTR;
for (i = 0; i < vi->xattr_shared_count; ++i) {
erofs_blk_t blkaddr =
xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
if (!i || blkaddr != it->it.blkaddr) {
if (i)
xattr_iter_end(&it->it, true);
it->it.page = erofs_get_meta_page(inode->i_sb,
blkaddr, false);
BUG_ON(IS_ERR(it->it.page));
it->it.kaddr = kmap_atomic(it->it.page);
it->it.blkaddr = blkaddr;
}
if ((ret = xattr_foreach(&it->it,
&find_xattr_handlers, NULL)) >= 0)
break;
}
if (vi->xattr_shared_count)
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_size;
}
static bool erofs_xattr_user_list(struct dentry *dentry)
{
return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
}
static bool erofs_xattr_trusted_list(struct dentry *dentry)
{
return capable(CAP_SYS_ADMIN);
}
int erofs_getxattr(struct inode *inode, int index,
const char *name,
void *buffer, size_t buffer_size)
{
int ret;
struct getxattr_iter it;
if (unlikely(name == NULL))
return -EINVAL;
init_inode_xattrs(inode);
it.index = index;
it.name.len = strlen(name);
if (it.name.len > EROFS_NAME_LEN)
return -ERANGE;
it.name.name = name;
it.buffer = buffer;
it.buffer_size = buffer_size;
it.it.sb = inode->i_sb;
ret = inline_getxattr(inode, &it);
if (ret == -ENOATTR)
ret = shared_getxattr(inode, &it);
return ret;
}
static int erofs_xattr_generic_get(const struct xattr_handler *handler,
struct dentry *unused, struct inode *inode,
const char *name, void *buffer, size_t size)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
switch (handler->flags) {
case EROFS_XATTR_INDEX_USER:
if (!test_opt(sbi, XATTR_USER))
return -EOPNOTSUPP;
break;
case EROFS_XATTR_INDEX_TRUSTED:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
break;
case EROFS_XATTR_INDEX_SECURITY:
break;
default:
return -EINVAL;
}
if (!vi->xattr_isize)
return -ENOATTR;
return erofs_getxattr(inode, handler->flags, name, buffer, size);
}
const struct xattr_handler erofs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = EROFS_XATTR_INDEX_USER,
.list = erofs_xattr_user_list,
.get = erofs_xattr_generic_get,
};
const struct xattr_handler erofs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.flags = EROFS_XATTR_INDEX_TRUSTED,
.list = erofs_xattr_trusted_list,
.get = erofs_xattr_generic_get,
};
#ifdef CONFIG_EROFS_FS_SECURITY
const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.flags = EROFS_XATTR_INDEX_SECURITY,
.get = erofs_xattr_generic_get,
};
#endif
#ifdef CONFIG_EROFS_FS_XATTR
const struct xattr_handler *erofs_xattr_handlers[] = {
&erofs_xattr_user_handler,
#ifdef CONFIG_EROFS_FS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
&erofs_xattr_trusted_handler,
#ifdef CONFIG_EROFS_FS_SECURITY
&erofs_xattr_security_handler,
#endif
NULL,
};
#endif
struct listxattr_iter {
struct xattr_iter it;
struct dentry *dentry;
char *buffer;
int buffer_size, buffer_ofs;
};
static int xattr_entrylist(struct xattr_iter *_it,
struct erofs_xattr_entry *entry)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
unsigned prefix_len;
const char *prefix;
const struct xattr_handler *h =
erofs_xattr_handler(entry->e_name_index);
if (h == NULL || (h->list != NULL && !h->list(it->dentry)))
return 1;
/* Note that at least one of 'prefix' and 'name' should be non-NULL */
prefix = h->prefix != NULL ? h->prefix : h->name;
prefix_len = strlen(prefix);
if (it->buffer == NULL) {
it->buffer_ofs += prefix_len + entry->e_name_len + 1;
return 1;
}
if (it->buffer_ofs + prefix_len
+ entry->e_name_len + 1 > it->buffer_size)
return -ERANGE;
memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
it->buffer_ofs += prefix_len;
return 0;
}
static int xattr_namelist(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
memcpy(it->buffer + it->buffer_ofs, buf, len);
it->buffer_ofs += len;
return 0;
}
static int xattr_skipvalue(struct xattr_iter *_it,
unsigned value_sz)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
it->buffer[it->buffer_ofs++] = '\0';
return 1;
}
static struct xattr_iter_handlers list_xattr_handlers = {
.entry = xattr_entrylist,
.name = xattr_namelist,
.alloc_buffer = xattr_skipvalue,
.value = NULL
};
static int inline_listxattr(struct listxattr_iter *it)
{
int ret;
unsigned remaining;
ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
if (ret < 0)
return ret;
remaining = ret;
while (remaining) {
if ((ret = xattr_foreach(&it->it,
&list_xattr_handlers, &remaining)) < 0)
break;
}
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_ofs;
}
static int shared_listxattr(struct listxattr_iter *it)
{
struct inode *const inode = d_inode(it->dentry);
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
unsigned i;
int ret = 0;
for (i = 0; i < vi->xattr_shared_count; ++i) {
erofs_blk_t blkaddr =
xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
if (!i || blkaddr != it->it.blkaddr) {
if (i)
xattr_iter_end(&it->it, true);
it->it.page = erofs_get_meta_page(inode->i_sb,
blkaddr, false);
BUG_ON(IS_ERR(it->it.page));
it->it.kaddr = kmap_atomic(it->it.page);
it->it.blkaddr = blkaddr;
}
if ((ret = xattr_foreach(&it->it,
&list_xattr_handlers, NULL)) < 0)
break;
}
if (vi->xattr_shared_count)
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_ofs;
}
ssize_t erofs_listxattr(struct dentry *dentry,
char *buffer, size_t buffer_size)
{
int ret;
struct listxattr_iter it;
init_inode_xattrs(d_inode(dentry));
it.dentry = dentry;
it.buffer = buffer;
it.buffer_size = buffer_size;
it.buffer_ofs = 0;
it.it.sb = dentry->d_sb;
ret = inline_listxattr(&it);
if (ret < 0 && ret != -ENOATTR)
return ret;
return shared_listxattr(&it);
}

93
drivers/staging/erofs/xattr.h Normal file
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@ -0,0 +1,93 @@
/* SPDX-License-Identifier: GPL-2.0
*
* linux/drivers/staging/erofs/xattr.h
*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#ifndef __EROFS_XATTR_H
#define __EROFS_XATTR_H
#include "internal.h"
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
/* Attribute not found */
#define ENOATTR ENODATA
static inline unsigned inlinexattr_header_size(struct inode *inode)
{
return sizeof(struct erofs_xattr_ibody_header)
+ sizeof(u32) * EROFS_V(inode)->xattr_shared_count;
}
static inline erofs_blk_t
xattrblock_addr(struct erofs_sb_info *sbi, unsigned xattr_id)
{
#ifdef CONFIG_EROFS_FS_XATTR
return sbi->xattr_blkaddr +
xattr_id * sizeof(__u32) / EROFS_BLKSIZ;
#else
return 0;
#endif
}
static inline unsigned
xattrblock_offset(struct erofs_sb_info *sbi, unsigned xattr_id)
{
return (xattr_id * sizeof(__u32)) % EROFS_BLKSIZ;
}
extern const struct xattr_handler erofs_xattr_user_handler;
extern const struct xattr_handler erofs_xattr_trusted_handler;
#ifdef CONFIG_EROFS_FS_SECURITY
extern const struct xattr_handler erofs_xattr_security_handler;
#endif
static inline const struct xattr_handler *erofs_xattr_handler(unsigned index)
{
static const struct xattr_handler *xattr_handler_map[] = {
[EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
#ifdef CONFIG_EROFS_FS_POSIX_ACL
[EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
[EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] =
&posix_acl_default_xattr_handler,
#endif
[EROFS_XATTR_INDEX_TRUSTED] = &erofs_xattr_trusted_handler,
#ifdef CONFIG_EROFS_FS_SECURITY
[EROFS_XATTR_INDEX_SECURITY] = &erofs_xattr_security_handler,
#endif
};
return index && index < ARRAY_SIZE(xattr_handler_map) ?
xattr_handler_map[index] : NULL;
}
#ifdef CONFIG_EROFS_FS_XATTR
extern const struct inode_operations erofs_generic_xattr_iops;
extern const struct inode_operations erofs_dir_xattr_iops;
int erofs_getxattr(struct inode *, int, const char *, void *, size_t);
ssize_t erofs_listxattr(struct dentry *, char *, size_t);
#else
static int __maybe_unused erofs_getxattr(struct inode *inode, int index,
const char *name,
void *buffer, size_t buffer_size)
{
return -ENOTSUPP;
}
static ssize_t __maybe_unused erofs_listxattr(struct dentry *dentry,
char *buffer, size_t buffer_size)
{
return -ENOTSUPP;
}
#endif
#endif