kernel-ark/fs/ext4/xattr.h
Kalpak Shah 6dd4ee7cab ext4: Expand extra_inodes space per the s_{want,min}_extra_isize fields
We need to make sure that existing ext3 filesystems can also avail the
new fields that have been added to the ext4 inode. We use
s_want_extra_isize and s_min_extra_isize to decide by how much we should
expand the inode. If EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature is set
then we expand the inode by max(s_want_extra_isize, s_min_extra_isize ,
sizeof(ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE) bytes. Actually it is
still an open question about whether users should be able to set
s_*_extra_isize smaller than the known fields or not.

This patch also adds the functionality to expand inodes to include the
newly added fields. We start by trying to expand by s_want_extra_isize
bytes and if its fails we try to expand by s_min_extra_isize bytes. This
is done by changing the i_extra_isize if enough space is available in
the inode and no EAs are present. If EAs are present and there is enough
space in the inode then the EAs in the inode are shifted to make space.
If enough space is not available in the inode due to the EAs then 1 or
more EAs are shifted to the external EA block. In the worst case when
even the external EA block does not have enough space we inform the user
that some EA would need to be deleted or s_min_extra_isize would have to
be reduced.

Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2007-07-18 09:19:57 -04:00

163 lines
4.5 KiB
C

/*
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
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 */
__u32 h_reserved[4]; /* 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))
# ifdef CONFIG_EXT4DEV_FS_XATTR
extern struct xattr_handler ext4_xattr_user_handler;
extern struct xattr_handler ext4_xattr_trusted_handler;
extern struct xattr_handler ext4_xattr_acl_access_handler;
extern struct xattr_handler ext4_xattr_acl_default_handler;
extern 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_list(struct inode *, char *, 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_xattr(void);
extern void exit_ext4_xattr(void);
extern struct xattr_handler *ext4_xattr_handlers[];
# else /* CONFIG_EXT4DEV_FS_XATTR */
static inline int
ext4_xattr_get(struct inode *inode, int name_index, const char *name,
void *buffer, size_t size, int flags)
{
return -EOPNOTSUPP;
}
static inline int
ext4_xattr_list(struct inode *inode, void *buffer, size_t size)
{
return -EOPNOTSUPP;
}
static inline int
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
const void *value, size_t size, int flags)
{
return -EOPNOTSUPP;
}
static inline int
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
const char *name, const void *value, size_t size, int flags)
{
return -EOPNOTSUPP;
}
static inline void
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
{
}
static inline void
ext4_xattr_put_super(struct super_block *sb)
{
}
static inline int
init_ext4_xattr(void)
{
return 0;
}
static inline void
exit_ext4_xattr(void)
{
}
static inline int
ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
struct ext4_inode *raw_inode, handle_t *handle)
{
return -EOPNOTSUPP;
}
#define ext4_xattr_handlers NULL
# endif /* CONFIG_EXT4DEV_FS_XATTR */
#ifdef CONFIG_EXT4DEV_FS_SECURITY
extern int ext4_init_security(handle_t *handle, struct inode *inode,
struct inode *dir);
#else
static inline int ext4_init_security(handle_t *handle, struct inode *inode,
struct inode *dir)
{
return 0;
}
#endif