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linux/fs/ext4/xattr.h
Theodore Ts'o bd9926e803 ext4: zero out inline data using memset() instead of empty_zero_page 
Not all architectures (in particular, sparc64) have empty_zero_page.
So instead of copying from empty_zero_page, use memset to clear the
inline data by signalling to ext4_xattr_set_entry() via a magic
pointer value, EXT4_ZERO_ATTR_VALUE, which is defined by casting -1 to
a pointer.

This fixes a build failure on sparc64, and the memset() should be more
efficient than using memcpy() anyway.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-12-11 03:31:49 -05:00

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/*
File: fs/ext4/xattr.h
On-disk format of extended attributes for the ext4 filesystem.
(C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/
#include <linux/xattr.h>
/* Magic value in attribute blocks */
#define EXT4_XATTR_MAGIC 0xEA020000
/* Maximum number of references to one attribute block */
#define EXT4_XATTR_REFCOUNT_MAX 1024
/* Name indexes */
#define EXT4_XATTR_INDEX_USER 1
#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS 2
#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT 3
#define EXT4_XATTR_INDEX_TRUSTED 4
#define EXT4_XATTR_INDEX_LUSTRE 5
#define EXT4_XATTR_INDEX_SECURITY 6
#define EXT4_XATTR_INDEX_SYSTEM 7
struct ext4_xattr_header {
__le32 h_magic; /* magic number for identification */
__le32 h_refcount; /* reference count */
__le32 h_blocks; /* number of disk blocks used */
__le32 h_hash; /* hash value of all attributes */
__le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
/* id = inum if refcount=1, blknum otherwise */
__u32 h_reserved[3]; /* zero right now */
};
struct ext4_xattr_ibody_header {
__le32 h_magic; /* magic number for identification */
};
struct ext4_xattr_entry {
__u8 e_name_len; /* length of name */
__u8 e_name_index; /* attribute name index */
__le16 e_value_offs; /* offset in disk block of value */
__le32 e_value_block; /* disk block attribute is stored on (n/i) */
__le32 e_value_size; /* size of attribute value */
__le32 e_hash; /* hash value of name and value */
char e_name[0]; /* attribute name */
};
#define EXT4_XATTR_PAD_BITS 2
#define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS)
#define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1)
#define EXT4_XATTR_LEN(name_len) \
(((name_len) + EXT4_XATTR_ROUND + \
sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
#define EXT4_XATTR_NEXT(entry) \
((struct ext4_xattr_entry *)( \
(char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
#define EXT4_XATTR_SIZE(size) \
(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
#define IHDR(inode, raw_inode) \
((struct ext4_xattr_ibody_header *) \
((void *)raw_inode + \
EXT4_GOOD_OLD_INODE_SIZE + \
EXT4_I(inode)->i_extra_isize))
#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
struct ext4_xattr_info {
int name_index;
const char *name;
const void *value;
size_t value_len;
};
struct ext4_xattr_search {
struct ext4_xattr_entry *first;
void *base;
void *end;
struct ext4_xattr_entry *here;
int not_found;
};
struct ext4_xattr_ibody_find {
struct ext4_xattr_search s;
struct ext4_iloc iloc;
};
extern const struct xattr_handler ext4_xattr_user_handler;
extern const struct xattr_handler ext4_xattr_trusted_handler;
extern const struct xattr_handler ext4_xattr_acl_access_handler;
extern const struct xattr_handler ext4_xattr_acl_default_handler;
extern const struct xattr_handler ext4_xattr_security_handler;
extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
extern void ext4_xattr_put_super(struct super_block *);
extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
struct ext4_inode *raw_inode, handle_t *handle);
extern int __init ext4_init_xattr(void);
extern void ext4_exit_xattr(void);
extern const struct xattr_handler *ext4_xattr_handlers[];
extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
struct ext4_xattr_ibody_find *is);
extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
const char *name,
void *buffer, size_t buffer_size);
extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
struct ext4_xattr_info *i,
struct ext4_xattr_ibody_find *is);
extern int ext4_has_inline_data(struct inode *inode);
extern int ext4_get_inline_size(struct inode *inode);
extern int ext4_get_max_inline_size(struct inode *inode);
extern int ext4_find_inline_data_nolock(struct inode *inode);
extern void ext4_write_inline_data(struct inode *inode,
struct ext4_iloc *iloc,
void *buffer, loff_t pos,
unsigned int len);
extern int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
unsigned int len);
extern int ext4_init_inline_data(handle_t *handle, struct inode *inode,
unsigned int len);
extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
extern int ext4_readpage_inline(struct inode *inode, struct page *page);
extern int ext4_try_to_write_inline_data(struct address_space *mapping,
struct inode *inode,
loff_t pos, unsigned len,
unsigned flags,
struct page **pagep);
extern int ext4_write_inline_data_end(struct inode *inode,
loff_t pos, unsigned len,
unsigned copied,
struct page *page);
extern struct buffer_head *
ext4_journalled_write_inline_data(struct inode *inode,
unsigned len,
struct page *page);
extern int ext4_da_write_inline_data_begin(struct address_space *mapping,
struct inode *inode,
loff_t pos, unsigned len,
unsigned flags,
struct page **pagep,
void **fsdata);
extern int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
unsigned len, unsigned copied,
struct page *page);
extern int ext4_try_add_inline_entry(handle_t *handle, struct dentry *dentry,
struct inode *inode);
extern int ext4_try_create_inline_dir(handle_t *handle,
struct inode *parent,
struct inode *inode);
extern int ext4_read_inline_dir(struct file *filp,
void *dirent, filldir_t filldir,
int *has_inline_data);
extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
const struct qstr *d_name,
struct ext4_dir_entry_2 **res_dir,
int *has_inline_data);
extern int ext4_delete_inline_entry(handle_t *handle,
struct inode *dir,
struct ext4_dir_entry_2 *de_del,
struct buffer_head *bh,
int *has_inline_data);
extern int empty_inline_dir(struct inode *dir, int *has_inline_data);
extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
struct ext4_dir_entry_2 **parent_de,
int *retval);
extern int ext4_inline_data_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo,
int *has_inline);
extern int ext4_try_to_evict_inline_data(handle_t *handle,
struct inode *inode,
int needed);
extern void ext4_inline_data_truncate(struct inode *inode, int *has_inline);
extern int ext4_convert_inline_data(struct inode *inode);
#ifdef CONFIG_EXT4_FS_SECURITY
extern int ext4_init_security(handle_t *handle, struct inode *inode,
struct inode *dir, const struct qstr *qstr);
#else
static inline int ext4_init_security(handle_t *handle, struct inode *inode,
struct inode *dir, const struct qstr *qstr)
{
return 0;
}
#endif
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