1 /* 2 * Copyright (c) 2000-2001 Silicon Graphics, Inc. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of version 2 of the GNU General Public License as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it would be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 11 * 12 * Further, this software is distributed without any warranty that it is 13 * free of the rightful claim of any third person regarding infringement 14 * or the like. Any license provided herein, whether implied or 15 * otherwise, applies only to this software file. Patent licenses, if 16 * any, provided herein do not apply to combinations of this program with 17 * other software, or any other product whatsoever. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write the Free Software Foundation, Inc., 59 21 * Temple Place - Suite 330, Boston MA 02111-1307, USA. 22 * 23 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, 24 * Mountain View, CA 94043, or: 25 * 26 * http://www.sgi.com 27 * 28 * For further information regarding this notice, see: 29 * 30 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ 31 */ 32 #ifndef __XFS_DIR_LEAF_H__ 33 #define __XFS_DIR_LEAF_H__ 34 35 /* 36 * Directory layout, internal structure, access macros, etc. 37 * 38 * Large directories are structured around Btrees where all the data 39 * elements are in the leaf nodes. Filenames are hashed into an int, 40 * then that int is used as the index into the Btree. Since the hashval 41 * of a filename may not be unique, we may have duplicate keys. The 42 * internal links in the Btree are logical block offsets into the file. 43 */ 44 45 struct uio; 46 struct xfs_bmap_free; 47 struct xfs_dabuf; 48 struct xfs_da_args; 49 struct xfs_da_state; 50 struct xfs_da_state_blk; 51 struct xfs_dir_put_args; 52 struct xfs_inode; 53 struct xfs_mount; 54 struct xfs_trans; 55 56 /*======================================================================== 57 * Directory Structure when equal to XFS_LBSIZE(mp) bytes. 58 *========================================================================*/ 59 60 /* 61 * This is the structure of the leaf nodes in the Btree. 62 * 63 * Struct leaf_entry's are packed from the top. Names grow from the bottom 64 * but are not packed. The freemap contains run-length-encoded entries 65 * for the free bytes after the leaf_entry's, but only the N largest such, 66 * smaller runs are dropped. When the freemap doesn't show enough space 67 * for an allocation, we compact the namelist area and try again. If we 68 * still don't have enough space, then we have to split the block. 69 * 70 * Since we have duplicate hash keys, for each key that matches, compare 71 * the actual string. The root and intermediate node search always takes 72 * the first-in-the-block key match found, so we should only have to work 73 * "forw"ard. If none matches, continue with the "forw"ard leaf nodes 74 * until the hash key changes or the filename is found. 75 * 76 * The parent directory and the self-pointer are explicitly represented 77 * (ie: there are entries for "." and ".."). 78 * 79 * Note that the count being a __uint16_t limits us to something like a 80 * blocksize of 1.3MB in the face of worst case (short) filenames. 81 */ 82 #define XFS_DIR_LEAF_MAPSIZE 3 /* how many freespace slots */ 83 84 typedef struct xfs_dir_leafblock { 85 struct xfs_dir_leaf_hdr { /* constant-structure header block */ 86 xfs_da_blkinfo_t info; /* block type, links, etc. */ 87 __uint16_t count; /* count of active leaf_entry's */ 88 __uint16_t namebytes; /* num bytes of name strings stored */ 89 __uint16_t firstused; /* first used byte in name area */ 90 __uint8_t holes; /* != 0 if blk needs compaction */ 91 __uint8_t pad1; 92 struct xfs_dir_leaf_map {/* RLE map of free bytes */ 93 __uint16_t base; /* base of free region */ 94 __uint16_t size; /* run length of free region */ 95 } freemap[XFS_DIR_LEAF_MAPSIZE]; /* N largest free regions */ 96 } hdr; 97 struct xfs_dir_leaf_entry { /* sorted on key, not name */ 98 xfs_dahash_t hashval; /* hash value of name */ 99 __uint16_t nameidx; /* index into buffer of name */ 100 __uint8_t namelen; /* length of name string */ 101 __uint8_t pad2; 102 } entries[1]; /* var sized array */ 103 struct xfs_dir_leaf_name { 104 xfs_dir_ino_t inumber; /* inode number for this key */ 105 __uint8_t name[1]; /* name string itself */ 106 } namelist[1]; /* grows from bottom of buf */ 107 } xfs_dir_leafblock_t; 108 typedef struct xfs_dir_leaf_hdr xfs_dir_leaf_hdr_t; 109 typedef struct xfs_dir_leaf_map xfs_dir_leaf_map_t; 110 typedef struct xfs_dir_leaf_entry xfs_dir_leaf_entry_t; 111 typedef struct xfs_dir_leaf_name xfs_dir_leaf_name_t; 112 113 /* 114 * Length of name for which a 512-byte block filesystem 115 * can get a double split. 116 */ 117 #define XFS_DIR_LEAF_CAN_DOUBLE_SPLIT_LEN \ 118 (512 - (uint)sizeof(xfs_dir_leaf_hdr_t) - \ 119 (uint)sizeof(xfs_dir_leaf_entry_t) * 2 - \ 120 (uint)sizeof(xfs_dir_leaf_name_t) * 2 - (MAXNAMELEN - 2) + 1 + 1) 121 122 typedef int (*xfs_dir_put_t)(struct xfs_dir_put_args *pa); 123 124 typedef union { 125 xfs_off_t o; /* offset (cookie) */ 126 /* 127 * Watch the order here (endian-ness dependent). 128 */ 129 struct { 130 #if __BYTE_ORDER == __LITTLE_ENDIAN 131 xfs_dahash_t h; /* hash value */ 132 __uint32_t be; /* block and entry */ 133 #else /* __BYTE_ORDER == __BIG_ENDIAN */ 134 __uint32_t be; /* block and entry */ 135 xfs_dahash_t h; /* hash value */ 136 #endif /* __BYTE_ORDER == __BIG_ENDIAN */ 137 } s; 138 } xfs_dircook_t; 139 140 #define XFS_PUT_COOKIE(c,mp,bno,entry,hash) \ 141 ((c).s.be = XFS_DA_MAKE_BNOENTRY(mp, bno, entry), (c).s.h = (hash)) 142 143 #define XFS_GET_DIR_INO_ARCH(mp,di,arch) \ 144 DIRINO_GET_ARCH(&(di),arch) 145 #define XFS_GET_DIR_INO(mp,di) \ 146 XFS_GET_DIR_INO_ARCH(mp,di,ARCH_NOCONVERT) 147 148 typedef struct xfs_dir_put_args 149 { 150 xfs_dircook_t cook; /* cookie of (next) entry */ 151 xfs_intino_t ino; /* inode number */ 152 struct xfs_dirent *dbp; /* buffer pointer */ 153 char *name; /* directory entry name */ 154 int namelen; /* length of name */ 155 int done; /* output: set if value was stored */ 156 xfs_dir_put_t put; /* put function ptr (i/o) */ 157 struct uio *uio; /* uio control structure */ 158 } xfs_dir_put_args_t; 159 160 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYNAME) 161 int xfs_dir_leaf_entsize_byname(int len); 162 #define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) xfs_dir_leaf_entsize_byname(len) 163 #else 164 #define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) /* space a name will use */ \ 165 ((uint)sizeof(xfs_dir_leaf_name_t)-1 + len) 166 #endif 167 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYENTRY) 168 int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry); 169 #define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) \ 170 xfs_dir_leaf_entsize_byentry(entry) 171 #else 172 #define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) /* space an entry will use */ \ 173 ((uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen) 174 #endif 175 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_NAMESTRUCT) 176 xfs_dir_leaf_name_t * 177 xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset); 178 #define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) \ 179 xfs_dir_leaf_namestruct(leafp,offset) 180 #else 181 #define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) /* point to name struct */ \ 182 ((xfs_dir_leaf_name_t *)&((char *)(leafp))[offset]) 183 #endif 184 185 /*======================================================================== 186 * Function prototypes for the kernel. 187 *========================================================================*/ 188 189 /* 190 * Internal routines when dirsize < XFS_LITINO(mp). 191 */ 192 int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent); 193 int xfs_dir_shortform_addname(struct xfs_da_args *args); 194 int xfs_dir_shortform_lookup(struct xfs_da_args *args); 195 int xfs_dir_shortform_to_leaf(struct xfs_da_args *args); 196 int xfs_dir_shortform_removename(struct xfs_da_args *args); 197 int xfs_dir_shortform_getdents(struct xfs_inode *dp, struct uio *uio, int *eofp, 198 struct xfs_dirent *dbp, xfs_dir_put_t put); 199 int xfs_dir_shortform_replace(struct xfs_da_args *args); 200 201 /* 202 * Internal routines when dirsize == XFS_LBSIZE(mp). 203 */ 204 int xfs_dir_leaf_to_node(struct xfs_da_args *args); 205 int xfs_dir_leaf_to_shortform(struct xfs_da_args *args); 206 207 /* 208 * Routines used for growing the Btree. 209 */ 210 int xfs_dir_leaf_create(struct xfs_da_args *args, xfs_dablk_t which_block, 211 struct xfs_dabuf **bpp); 212 int xfs_dir_leaf_split(struct xfs_da_state *state, 213 struct xfs_da_state_blk *oldblk, 214 struct xfs_da_state_blk *newblk); 215 int xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer, 216 struct xfs_da_args *args, int insertion_index); 217 int xfs_dir_leaf_addname(struct xfs_da_args *args); 218 int xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer, 219 struct xfs_da_args *args, 220 int *index_found_at); 221 int xfs_dir_leaf_remove(struct xfs_trans *trans, 222 struct xfs_dabuf *leaf_buffer, 223 int index_to_remove); 224 int xfs_dir_leaf_getdents_int(struct xfs_dabuf *bp, struct xfs_inode *dp, 225 xfs_dablk_t bno, struct uio *uio, 226 int *eobp, struct xfs_dirent *dbp, 227 xfs_dir_put_t put, xfs_daddr_t nextda); 228 229 /* 230 * Routines used for shrinking the Btree. 231 */ 232 int xfs_dir_leaf_toosmall(struct xfs_da_state *state, int *retval); 233 void xfs_dir_leaf_unbalance(struct xfs_da_state *state, 234 struct xfs_da_state_blk *drop_blk, 235 struct xfs_da_state_blk *save_blk); 236 237 /* 238 * Utility routines. 239 */ 240 uint xfs_dir_leaf_lasthash(struct xfs_dabuf *bp, int *count); 241 int xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp, 242 struct xfs_dabuf *leaf2_bp); 243 int xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa); 244 int xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa); 245 int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino); 246 247 248 /* 249 * Global data. 250 */ 251 extern xfs_dahash_t xfs_dir_hash_dot, xfs_dir_hash_dotdot; 252 253 #endif /* __XFS_DIR_LEAF_H__ */ 254