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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 * 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__ */