Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 { |
Nathan Scott | f016bad | 2005-09-08 15:30:05 +1000 | [diff] [blame^] | 130 | #ifndef XFS_NATIVE_HOST |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | xfs_dahash_t h; /* hash value */ |
| 132 | __uint32_t be; /* block and entry */ |
Nathan Scott | f016bad | 2005-09-08 15:30:05 +1000 | [diff] [blame^] | 133 | #else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | __uint32_t be; /* block and entry */ |
| 135 | xfs_dahash_t h; /* hash value */ |
Nathan Scott | f016bad | 2005-09-08 15:30:05 +1000 | [diff] [blame^] | 136 | #endif /* XFS_NATIVE_HOST */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | typedef struct xfs_dir_put_args |
| 144 | { |
| 145 | xfs_dircook_t cook; /* cookie of (next) entry */ |
| 146 | xfs_intino_t ino; /* inode number */ |
| 147 | struct xfs_dirent *dbp; /* buffer pointer */ |
| 148 | char *name; /* directory entry name */ |
| 149 | int namelen; /* length of name */ |
| 150 | int done; /* output: set if value was stored */ |
| 151 | xfs_dir_put_t put; /* put function ptr (i/o) */ |
| 152 | struct uio *uio; /* uio control structure */ |
| 153 | } xfs_dir_put_args_t; |
| 154 | |
| 155 | #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYNAME) |
| 156 | int xfs_dir_leaf_entsize_byname(int len); |
| 157 | #define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) xfs_dir_leaf_entsize_byname(len) |
| 158 | #else |
| 159 | #define XFS_DIR_LEAF_ENTSIZE_BYNAME(len) /* space a name will use */ \ |
| 160 | ((uint)sizeof(xfs_dir_leaf_name_t)-1 + len) |
| 161 | #endif |
| 162 | #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYENTRY) |
| 163 | int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry); |
| 164 | #define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) \ |
| 165 | xfs_dir_leaf_entsize_byentry(entry) |
| 166 | #else |
| 167 | #define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry) /* space an entry will use */ \ |
| 168 | ((uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen) |
| 169 | #endif |
| 170 | #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_NAMESTRUCT) |
| 171 | xfs_dir_leaf_name_t * |
| 172 | xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset); |
| 173 | #define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) \ |
| 174 | xfs_dir_leaf_namestruct(leafp,offset) |
| 175 | #else |
| 176 | #define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset) /* point to name struct */ \ |
| 177 | ((xfs_dir_leaf_name_t *)&((char *)(leafp))[offset]) |
| 178 | #endif |
| 179 | |
| 180 | /*======================================================================== |
| 181 | * Function prototypes for the kernel. |
| 182 | *========================================================================*/ |
| 183 | |
| 184 | /* |
| 185 | * Internal routines when dirsize < XFS_LITINO(mp). |
| 186 | */ |
| 187 | int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent); |
| 188 | int xfs_dir_shortform_addname(struct xfs_da_args *args); |
| 189 | int xfs_dir_shortform_lookup(struct xfs_da_args *args); |
| 190 | int xfs_dir_shortform_to_leaf(struct xfs_da_args *args); |
| 191 | int xfs_dir_shortform_removename(struct xfs_da_args *args); |
| 192 | int xfs_dir_shortform_getdents(struct xfs_inode *dp, struct uio *uio, int *eofp, |
| 193 | struct xfs_dirent *dbp, xfs_dir_put_t put); |
| 194 | int xfs_dir_shortform_replace(struct xfs_da_args *args); |
| 195 | |
| 196 | /* |
| 197 | * Internal routines when dirsize == XFS_LBSIZE(mp). |
| 198 | */ |
| 199 | int xfs_dir_leaf_to_node(struct xfs_da_args *args); |
| 200 | int xfs_dir_leaf_to_shortform(struct xfs_da_args *args); |
| 201 | |
| 202 | /* |
| 203 | * Routines used for growing the Btree. |
| 204 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | int xfs_dir_leaf_split(struct xfs_da_state *state, |
| 206 | struct xfs_da_state_blk *oldblk, |
| 207 | struct xfs_da_state_blk *newblk); |
| 208 | int xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer, |
| 209 | struct xfs_da_args *args, int insertion_index); |
| 210 | int xfs_dir_leaf_addname(struct xfs_da_args *args); |
| 211 | int xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer, |
| 212 | struct xfs_da_args *args, |
| 213 | int *index_found_at); |
| 214 | int xfs_dir_leaf_remove(struct xfs_trans *trans, |
| 215 | struct xfs_dabuf *leaf_buffer, |
| 216 | int index_to_remove); |
| 217 | int xfs_dir_leaf_getdents_int(struct xfs_dabuf *bp, struct xfs_inode *dp, |
| 218 | xfs_dablk_t bno, struct uio *uio, |
| 219 | int *eobp, struct xfs_dirent *dbp, |
| 220 | xfs_dir_put_t put, xfs_daddr_t nextda); |
| 221 | |
| 222 | /* |
| 223 | * Routines used for shrinking the Btree. |
| 224 | */ |
| 225 | int xfs_dir_leaf_toosmall(struct xfs_da_state *state, int *retval); |
| 226 | void xfs_dir_leaf_unbalance(struct xfs_da_state *state, |
| 227 | struct xfs_da_state_blk *drop_blk, |
| 228 | struct xfs_da_state_blk *save_blk); |
| 229 | |
| 230 | /* |
| 231 | * Utility routines. |
| 232 | */ |
| 233 | uint xfs_dir_leaf_lasthash(struct xfs_dabuf *bp, int *count); |
| 234 | int xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp, |
| 235 | struct xfs_dabuf *leaf2_bp); |
| 236 | int xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa); |
| 237 | int xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa); |
| 238 | int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino); |
| 239 | |
| 240 | |
| 241 | /* |
| 242 | * Global data. |
| 243 | */ |
| 244 | extern xfs_dahash_t xfs_dir_hash_dot, xfs_dir_hash_dotdot; |
| 245 | |
| 246 | #endif /* __XFS_DIR_LEAF_H__ */ |