[deliverable/linux.git] / fs / xfs / xfs_dir_leaf.h

/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_DIR_LEAF_H__
#define	__XFS_DIR_LEAF_H__

/*
 * Directory layout, internal structure, access macros, etc.
 *
 * Large directories are structured around Btrees where all the data
 * elements are in the leaf nodes.  Filenames are hashed into an int,
 * then that int is used as the index into the Btree.  Since the hashval
 * of a filename may not be unique, we may have duplicate keys.  The
 * internal links in the Btree are logical block offsets into the file.
 */

struct uio;
struct xfs_bmap_free;
struct xfs_dabuf;
struct xfs_da_args;
struct xfs_da_state;
struct xfs_da_state_blk;
struct xfs_dir_put_args;
struct xfs_inode;
struct xfs_mount;
struct xfs_trans;

/*========================================================================
 * Directory Structure when equal to XFS_LBSIZE(mp) bytes.
 *========================================================================*/

/*
 * This is the structure of the leaf nodes in the Btree.
 *
 * Struct leaf_entry's are packed from the top.  Names grow from the bottom
 * but are not packed.  The freemap contains run-length-encoded entries
 * for the free bytes after the leaf_entry's, but only the N largest such,
 * smaller runs are dropped.  When the freemap doesn't show enough space
 * for an allocation, we compact the namelist area and try again.  If we
 * still don't have enough space, then we have to split the block.
 *
 * Since we have duplicate hash keys, for each key that matches, compare
 * the actual string.  The root and intermediate node search always takes
 * the first-in-the-block key match found, so we should only have to work
 * "forw"ard.  If none matches, continue with the "forw"ard leaf nodes
 * until the hash key changes or the filename is found.
 *
 * The parent directory and the self-pointer are explicitly represented
 * (ie: there are entries for "." and "..").
 *
 * Note that the count being a __uint16_t limits us to something like a
 * blocksize of 1.3MB in the face of worst case (short) filenames.
 */
#define XFS_DIR_LEAF_MAPSIZE	3	/* how many freespace slots */

typedef struct xfs_dir_leaf_map {	/* RLE map of free bytes */
	__uint16_t	base;	 	/* base of free region */
	__uint16_t	size; 		/* run length of free region */
} xfs_dir_leaf_map_t;

typedef struct xfs_dir_leaf_hdr {	/* constant-structure header block */
	xfs_da_blkinfo_t info;		/* block type, links, etc. */
	__uint16_t	count;		/* count of active leaf_entry's */
	__uint16_t	namebytes;	/* num bytes of name strings stored */
	__uint16_t	firstused;	/* first used byte in name area */
	__uint8_t	holes;		/* != 0 if blk needs compaction */
	__uint8_t	pad1;
	xfs_dir_leaf_map_t freemap[XFS_DIR_LEAF_MAPSIZE];
} xfs_dir_leaf_hdr_t;

typedef struct xfs_dir_leaf_entry {	/* sorted on key, not name */
	xfs_dahash_t	hashval;	/* hash value of name */
	__uint16_t	nameidx;	/* index into buffer of name */
	__uint8_t	namelen;	/* length of name string */
	__uint8_t	pad2;
} xfs_dir_leaf_entry_t;

typedef struct xfs_dir_leaf_name {
	xfs_dir_ino_t	inumber;	/* inode number for this key */
	__uint8_t	name[1];	/* name string itself */
} xfs_dir_leaf_name_t;

typedef struct xfs_dir_leafblock {
	xfs_dir_leaf_hdr_t	hdr;	/* constant-structure header block */
	xfs_dir_leaf_entry_t	entries[1];	/* var sized array */
	xfs_dir_leaf_name_t	namelist[1];	/* grows from bottom of buf */
} xfs_dir_leafblock_t;

/*
 * Length of name for which a 512-byte block filesystem
 * can get a double split.
 */
#define	XFS_DIR_LEAF_CAN_DOUBLE_SPLIT_LEN	\
	(512 - (uint)sizeof(xfs_dir_leaf_hdr_t) - \
	 (uint)sizeof(xfs_dir_leaf_entry_t) * 2 - \
	 (uint)sizeof(xfs_dir_leaf_name_t) * 2 - (MAXNAMELEN - 2) + 1 + 1)

typedef int (*xfs_dir_put_t)(struct xfs_dir_put_args *pa);

typedef union {
	xfs_off_t		o;		/* offset (cookie) */
	/*
	 * Watch the order here (endian-ness dependent).
	 */
	struct {
#ifndef XFS_NATIVE_HOST
		xfs_dahash_t	h;	/* hash value */
		__uint32_t	be;	/* block and entry */
#else
		__uint32_t	be;	/* block and entry */
		xfs_dahash_t	h;	/* hash value */
#endif /* XFS_NATIVE_HOST */
	} s;
} xfs_dircook_t;

#define	XFS_PUT_COOKIE(c,mp,bno,entry,hash)	\
	((c).s.be = XFS_DA_MAKE_BNOENTRY(mp, bno, entry), (c).s.h = (hash))

typedef struct xfs_dir_put_args {
	xfs_dircook_t	cook;		/* cookie of (next) entry */
	xfs_intino_t	ino;		/* inode number */
	struct xfs_dirent *dbp;		/* buffer pointer */
	char		*name;		/* directory entry name */
	int		namelen;	/* length of name */
	int		done;		/* output: set if value was stored */
	xfs_dir_put_t	put;		/* put function ptr (i/o) */
	struct uio	*uio;		/* uio control structure */
} xfs_dir_put_args_t;

#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len)	\
	xfs_dir_leaf_entsize_byname(len)
static inline int xfs_dir_leaf_entsize_byname(int len)
{
	return (uint)sizeof(xfs_dir_leaf_name_t)-1 + len;
}

#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry)	\
	xfs_dir_leaf_entsize_byentry(entry)
static inline int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry)
{
	return (uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen;
}

#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset)	\
	xfs_dir_leaf_namestruct(leafp,offset)
static inline xfs_dir_leaf_name_t *
xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset)
{
	return (xfs_dir_leaf_name_t *)&((char *)(leafp))[offset];
}

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Internal routines when dirsize < XFS_LITINO(mp).
 */
int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent);
int xfs_dir_shortform_addname(struct xfs_da_args *args);
int xfs_dir_shortform_lookup(struct xfs_da_args *args);
int xfs_dir_shortform_to_leaf(struct xfs_da_args *args);
int xfs_dir_shortform_removename(struct xfs_da_args *args);
int xfs_dir_shortform_getdents(struct xfs_inode *dp, struct uio *uio, int *eofp,
			       struct xfs_dirent *dbp, xfs_dir_put_t put);
int xfs_dir_shortform_replace(struct xfs_da_args *args);

/*
 * Internal routines when dirsize == XFS_LBSIZE(mp).
 */
int xfs_dir_leaf_to_node(struct xfs_da_args *args);
int xfs_dir_leaf_to_shortform(struct xfs_da_args *args);

/*
 * Routines used for growing the Btree.
 */
int	xfs_dir_leaf_split(struct xfs_da_state *state,
				  struct xfs_da_state_blk *oldblk,
				  struct xfs_da_state_blk *newblk);
int	xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer,
				struct xfs_da_args *args, int insertion_index);
int	xfs_dir_leaf_addname(struct xfs_da_args *args);
int	xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer,
				       struct xfs_da_args *args,
				       int *index_found_at);
int	xfs_dir_leaf_remove(struct xfs_trans *trans,
				   struct xfs_dabuf *leaf_buffer,
				   int index_to_remove);
int	xfs_dir_leaf_getdents_int(struct xfs_dabuf *bp, struct xfs_inode *dp,
					 xfs_dablk_t bno, struct uio *uio,
					 int *eobp, struct xfs_dirent *dbp,
					 xfs_dir_put_t put, xfs_daddr_t nextda);

/*
 * Routines used for shrinking the Btree.
 */
int	xfs_dir_leaf_toosmall(struct xfs_da_state *state, int *retval);
void	xfs_dir_leaf_unbalance(struct xfs_da_state *state,
					     struct xfs_da_state_blk *drop_blk,
					     struct xfs_da_state_blk *save_blk);

/*
 * Utility routines.
 */
uint	xfs_dir_leaf_lasthash(struct xfs_dabuf *bp, int *count);
int	xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp,
				  struct xfs_dabuf *leaf2_bp);
int	xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa);
int	xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa);
int	xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);

/*
 * Global data.
 */
extern xfs_dahash_t	xfs_dir_hash_dot, xfs_dir_hash_dotdot;

#endif /* __XFS_DIR_LEAF_H__ */
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4	13	*
7b718769 NS	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4 LT	17	*/
	18	#ifndef __XFS_DIR_LEAF_H__
	19	#define __XFS_DIR_LEAF_H__
	20
	21	/*
	22	* Directory layout, internal structure, access macros, etc.
	23	*
	24	* Large directories are structured around Btrees where all the data
	25	* elements are in the leaf nodes. Filenames are hashed into an int,
	26	* then that int is used as the index into the Btree. Since the hashval
	27	* of a filename may not be unique, we may have duplicate keys. The
	28	* internal links in the Btree are logical block offsets into the file.
	29	*/
	30
	31	struct uio;
	32	struct xfs_bmap_free;
	33	struct xfs_dabuf;
	34	struct xfs_da_args;
	35	struct xfs_da_state;
	36	struct xfs_da_state_blk;
	37	struct xfs_dir_put_args;
	38	struct xfs_inode;
	39	struct xfs_mount;
	40	struct xfs_trans;
	41
	42	/*========================================================================
	43	* Directory Structure when equal to XFS_LBSIZE(mp) bytes.
	44	========================================================================/
	45
	46	/*
	47	* This is the structure of the leaf nodes in the Btree.
	48	*
	49	* Struct leaf_entry's are packed from the top. Names grow from the bottom
	50	* but are not packed. The freemap contains run-length-encoded entries
	51	* for the free bytes after the leaf_entry's, but only the N largest such,
	52	* smaller runs are dropped. When the freemap doesn't show enough space
	53	* for an allocation, we compact the namelist area and try again. If we
	54	* still don't have enough space, then we have to split the block.
	55	*
	56	* Since we have duplicate hash keys, for each key that matches, compare
	57	* the actual string. The root and intermediate node search always takes
	58	* the first-in-the-block key match found, so we should only have to work
	59	* "forw"ard. If none matches, continue with the "forw"ard leaf nodes
	60	* until the hash key changes or the filename is found.
	61	*
	62	* The parent directory and the self-pointer are explicitly represented
	63	* (ie: there are entries for "." and "..").
	64	*
	65	* Note that the count being a __uint16_t limits us to something like a
	66	* blocksize of 1.3MB in the face of worst case (short) filenames.
	67	*/
	68	#define XFS_DIR_LEAF_MAPSIZE 3 /* how many freespace slots */
	69
3762ec6b NS	70	typedef struct xfs_dir_leaf_map { /* RLE map of free bytes */
	71	__uint16_t base; /* base of free region */
	72	__uint16_t size; /* run length of free region */
	73	} xfs_dir_leaf_map_t;
	74
	75	typedef struct xfs_dir_leaf_hdr { /* constant-structure header block */
	76	xfs_da_blkinfo_t info; /* block type, links, etc. */
	77	__uint16_t count; /* count of active leaf_entry's */
	78	__uint16_t namebytes; /* num bytes of name strings stored */
	79	__uint16_t firstused; /* first used byte in name area */
	80	__uint8_t holes; /* != 0 if blk needs compaction */
	81	__uint8_t pad1;
	82	xfs_dir_leaf_map_t freemap[XFS_DIR_LEAF_MAPSIZE];
	83	} xfs_dir_leaf_hdr_t;
	84
	85	typedef struct xfs_dir_leaf_entry { /* sorted on key, not name */
	86	xfs_dahash_t hashval; /* hash value of name */
	87	__uint16_t nameidx; /* index into buffer of name */
	88	__uint8_t namelen; /* length of name string */
	89	__uint8_t pad2;
	90	} xfs_dir_leaf_entry_t;
	91
	92	typedef struct xfs_dir_leaf_name {
	93	xfs_dir_ino_t inumber; /* inode number for this key */
	94	__uint8_t name[1]; /* name string itself */
	95	} xfs_dir_leaf_name_t;
	96
1da177e4	97	typedef struct xfs_dir_leafblock {
3762ec6b NS	98	xfs_dir_leaf_hdr_t hdr; /* constant-structure header block */
	99	xfs_dir_leaf_entry_t entries[1]; /* var sized array */
	100	xfs_dir_leaf_name_t namelist[1]; /* grows from bottom of buf */
1da177e4	101	} xfs_dir_leafblock_t;
1da177e4 LT	102
	103	/*
	104	* Length of name for which a 512-byte block filesystem
	105	* can get a double split.
	106	*/
	107	#define XFS_DIR_LEAF_CAN_DOUBLE_SPLIT_LEN \
	108	(512 - (uint)sizeof(xfs_dir_leaf_hdr_t) - \
	109	(uint)sizeof(xfs_dir_leaf_entry_t) * 2 - \
	110	(uint)sizeof(xfs_dir_leaf_name_t) * 2 - (MAXNAMELEN - 2) + 1 + 1)
	111
	112	typedef int (xfs_dir_put_t)(struct xfs_dir_put_args pa);
	113
	114	typedef union {
	115	xfs_off_t o; /* offset (cookie) */
	116	/*
	117	* Watch the order here (endian-ness dependent).
	118	*/
	119	struct {
f016bad6	120	#ifndef XFS_NATIVE_HOST
1da177e4 LT	121	xfs_dahash_t h; /* hash value */
1da177e4 LT	122	__uint32_t be; /* block and entry */
f016bad6	123	#else
1da177e4 LT	124	__uint32_t be; /* block and entry */
1da177e4 LT	125	xfs_dahash_t h; /* hash value */
f016bad6	126	#endif /* XFS_NATIVE_HOST */
1da177e4 LT	127	} s;
	128	} xfs_dircook_t;
	129
	130	#define XFS_PUT_COOKIE(c,mp,bno,entry,hash) \
	131	((c).s.be = XFS_DA_MAKE_BNOENTRY(mp, bno, entry), (c).s.h = (hash))
	132
3762ec6b	133	typedef struct xfs_dir_put_args {
1da177e4 LT	134	xfs_dircook_t cook; /* cookie of (next) entry */
1da177e4 LT	135	xfs_intino_t ino; /* inode number */
3762ec6b	136	struct xfs_dirent dbp; / buffer pointer */
1da177e4 LT	137	char name; / directory entry name */
	138	int namelen; /* length of name */
	139	int done; /* output: set if value was stored */
	140	xfs_dir_put_t put; /* put function ptr (i/o) */
	141	struct uio uio; / uio control structure */
	142	} xfs_dir_put_args_t;
	143
3762ec6b NS	144	#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) \
3762ec6b NS	145	xfs_dir_leaf_entsize_byname(len)
a844f451 NS	146	static inline int xfs_dir_leaf_entsize_byname(int len)
	147	{
	148	return (uint)sizeof(xfs_dir_leaf_name_t)-1 + len;
	149	}
	150
1da177e4 LT	151	#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) \
1da177e4 LT	152	xfs_dir_leaf_entsize_byentry(entry)
a844f451 NS	153	static inline int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry)
	154	{
	155	return (uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen;
	156	}
	157
1da177e4 LT	158	#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) \
1da177e4 LT	159	xfs_dir_leaf_namestruct(leafp,offset)
a844f451 NS	160	static inline xfs_dir_leaf_name_t *
	161	xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset)
	162	{
	163	return (xfs_dir_leaf_name_t )&((char )(leafp))[offset];
	164	}
1da177e4 LT	165
	166	/*========================================================================
	167	* Function prototypes for the kernel.
	168	========================================================================/
	169
	170	/*
	171	* Internal routines when dirsize < XFS_LITINO(mp).
	172	*/
	173	int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent);
	174	int xfs_dir_shortform_addname(struct xfs_da_args *args);
	175	int xfs_dir_shortform_lookup(struct xfs_da_args *args);
	176	int xfs_dir_shortform_to_leaf(struct xfs_da_args *args);
	177	int xfs_dir_shortform_removename(struct xfs_da_args *args);
	178	int xfs_dir_shortform_getdents(struct xfs_inode dp, struct uio uio, int *eofp,
a844f451	179	struct xfs_dirent *dbp, xfs_dir_put_t put);
1da177e4 LT	180	int xfs_dir_shortform_replace(struct xfs_da_args *args);
	181
	182	/*
	183	* Internal routines when dirsize == XFS_LBSIZE(mp).
	184	*/
	185	int xfs_dir_leaf_to_node(struct xfs_da_args *args);
	186	int xfs_dir_leaf_to_shortform(struct xfs_da_args *args);
	187
	188	/*
	189	* Routines used for growing the Btree.
	190	*/
1da177e4 LT	191	int xfs_dir_leaf_split(struct xfs_da_state *state,
	192	struct xfs_da_state_blk *oldblk,
	193	struct xfs_da_state_blk *newblk);
	194	int xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer,
	195	struct xfs_da_args *args, int insertion_index);
	196	int xfs_dir_leaf_addname(struct xfs_da_args *args);
	197	int xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer,
	198	struct xfs_da_args *args,
	199	int *index_found_at);
	200	int xfs_dir_leaf_remove(struct xfs_trans *trans,
	201	struct xfs_dabuf *leaf_buffer,
	202	int index_to_remove);
	203	int xfs_dir_leaf_getdents_int(struct xfs_dabuf bp, struct xfs_inode dp,
	204	xfs_dablk_t bno, struct uio *uio,
	205	int eobp, struct xfs_dirent dbp,
	206	xfs_dir_put_t put, xfs_daddr_t nextda);
	207
	208	/*
	209	* Routines used for shrinking the Btree.
	210	*/
	211	int xfs_dir_leaf_toosmall(struct xfs_da_state state, int retval);
	212	void xfs_dir_leaf_unbalance(struct xfs_da_state *state,
	213	struct xfs_da_state_blk *drop_blk,
	214	struct xfs_da_state_blk *save_blk);
	215
	216	/*
	217	* Utility routines.
	218	*/
	219	uint xfs_dir_leaf_lasthash(struct xfs_dabuf bp, int count);
	220	int xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp,
	221	struct xfs_dabuf *leaf2_bp);
	222	int xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa);
	223	int xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa);
	224	int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);
	225
1da177e4 LT	226	/*
	227	* Global data.
	228	*/
	229	extern xfs_dahash_t xfs_dir_hash_dot, xfs_dir_hash_dotdot;
	230
	231	#endif /* __XFS_DIR_LEAF_H__ */