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af65207c76
linux-next/fs/ext4/xattr.h
Tahsin Erdogan af65207c76 ext4: fix __ext4_new_inode() journal credits calculation 
ea_inode feature allows creating extended attributes that are up to
64k in size. Update __ext4_new_inode() to pick increased credit limits.

To avoid overallocating too many journal credits, update
__ext4_xattr_set_credits() to make a distinction between xattr create
vs update. This helps __ext4_new_inode() because all attributes are
known to be new, so we can save credits that are normally needed to
delete old values.

Also, have fscrypt specify its maximum context size so that we don't
end up allocating credits for 64k size.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-07-06 00:01:59 -04:00

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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
#define EXT4_XATTR_INDEX_RICHACL 8
#define EXT4_XATTR_INDEX_ENCRYPTION 9
#define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */
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_inum; /* inode in which the value is stored */
__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))
/*
* The minimum size of EA value when you start storing it in an external inode
* size of block - size of header - size of 1 entry - 4 null bytes
*/
#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \
((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)
#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 {
const char *name;
const void *value;
size_t value_len;
int name_index;
int in_inode;
};
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;
};
struct ext4_xattr_inode_array {
unsigned int count; /* # of used items in the array */
struct inode *inodes[0];
};
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_security_handler;
#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
/*
* The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
* The first is to signal that there the inline xattrs and data are
* taking up so much space that we might as well not keep trying to
* expand it. The second is that xattr_sem is taken for writing, so
* we shouldn't try to recurse into the inode expansion. For this
* second case, we need to make sure that we take save and restore the
* NO_EXPAND state flag appropriately.
*/
static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
{
down_write(&EXT4_I(inode)->xattr_sem);
*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
}
static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
{
if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
return 0;
*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
return 1;
}
static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
{
if (*save == 0)
ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
up_write(&EXT4_I(inode)->xattr_sem);
}
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 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
bool is_create, int *credits);
extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
struct buffer_head *block_bh, size_t value_len,
bool is_create);
extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
struct ext4_xattr_inode_array **array,
int extra_credits);
extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
struct ext4_inode *raw_inode, handle_t *handle);
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 struct mb_cache *ext4_xattr_create_cache(void);
extern void ext4_xattr_destroy_cache(struct mb_cache *);
#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
#ifdef CONFIG_LOCKDEP
extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
#else
static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
#endif
extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);
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