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* 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
* 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.
(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 {
xfs_dahash_t h; /* hash value */
__uint32_t be; /* block and entry */
__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) = 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;
static inline int xfs_dir_leaf_entsize_byname(int len)
return (uint)sizeof(xfs_dir_leaf_name_t)-1 + len;
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) \
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__ */