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Diffstat (limited to 'fs/xfs/xfs_dir_leaf.h')
| -rw-r--r-- | fs/xfs/xfs_dir_leaf.h | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/fs/xfs/xfs_dir_leaf.h b/fs/xfs/xfs_dir_leaf.h new file mode 100644 index 000000000000..00d68d33cc7a --- /dev/null +++ b/fs/xfs/xfs_dir_leaf.h @@ -0,0 +1,248 @@ +/* + * Copyright (c) 2000-2001 Silicon Graphics, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 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. + * + * Further, this software is distributed without any warranty that it is + * free of the rightful claim of any third person regarding infringement + * or the like. Any license provided herein, whether implied or + * otherwise, applies only to this software file. Patent licenses, if + * any, provided herein do not apply to combinations of this program with + * other software, or any other product whatsoever. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, + * Mountain View, CA 94043, or: + * + * http://www.sgi.com + * + * For further information regarding this notice, see: + * + * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ + */ +#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_leafblock { + 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; + 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 */ + } freemap[XFS_DIR_LEAF_MAPSIZE]; /* N largest free regions */ + } hdr; + 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; + } entries[1]; /* var sized array */ + struct xfs_dir_leaf_name { + xfs_dir_ino_t inumber; /* inode number for this key */ + __uint8_t name[1]; /* name string itself */ + } namelist[1]; /* grows from bottom of buf */ +} xfs_dir_leafblock_t; +typedef struct xfs_dir_leaf_hdr xfs_dir_leaf_hdr_t; +typedef struct xfs_dir_leaf_map xfs_dir_leaf_map_t; +typedef struct xfs_dir_leaf_entry xfs_dir_leaf_entry_t; +typedef struct xfs_dir_leaf_name xfs_dir_leaf_name_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 { +#if __BYTE_ORDER == __LITTLE_ENDIAN + xfs_dahash_t h; /* hash value */ + __uint32_t be; /* block and entry */ +#else /* __BYTE_ORDER == __BIG_ENDIAN */ + __uint32_t be; /* block and entry */ + xfs_dahash_t h; /* hash value */ +#endif /* __BYTE_ORDER == __BIG_ENDIAN */ + } 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; + +#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYNAME) +int xfs_dir_leaf_entsize_byname(int len); +#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) xfs_dir_leaf_entsize_byname(len) +#else +#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) /* space a name will use */ \ + ((uint)sizeof(xfs_dir_leaf_name_t)-1 + len) +#endif +#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYENTRY) +int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry); +#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) \ + xfs_dir_leaf_entsize_byentry(entry) +#else +#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) /* space an entry will use */ \ + ((uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen) +#endif +#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_NAMESTRUCT) +xfs_dir_leaf_name_t * +xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset); +#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) \ + xfs_dir_leaf_namestruct(leafp,offset) +#else +#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) /* point to name struct */ \ + ((xfs_dir_leaf_name_t *)&((char *)(leafp))[offset]) +#endif + +/*======================================================================== + * 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_create(struct xfs_da_args *args, xfs_dablk_t which_block, + struct xfs_dabuf **bpp); +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__ */ |