blob: dd423ce1bc8d082a177effddde9f35b341932996 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
45struct uio;
46struct xfs_bmap_free;
47struct xfs_dabuf;
48struct xfs_da_args;
49struct xfs_da_state;
50struct xfs_da_state_blk;
51struct xfs_dir_put_args;
52struct xfs_inode;
53struct xfs_mount;
54struct 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
84typedef 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;
108typedef struct xfs_dir_leaf_hdr xfs_dir_leaf_hdr_t;
109typedef struct xfs_dir_leaf_map xfs_dir_leaf_map_t;
110typedef struct xfs_dir_leaf_entry xfs_dir_leaf_entry_t;
111typedef 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
122typedef int (*xfs_dir_put_t)(struct xfs_dir_put_args *pa);
123
124typedef 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
143typedef 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)
156int 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)
163int 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)
171xfs_dir_leaf_name_t *
172xfs_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 */
187int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent);
188int xfs_dir_shortform_addname(struct xfs_da_args *args);
189int xfs_dir_shortform_lookup(struct xfs_da_args *args);
190int xfs_dir_shortform_to_leaf(struct xfs_da_args *args);
191int xfs_dir_shortform_removename(struct xfs_da_args *args);
192int xfs_dir_shortform_getdents(struct xfs_inode *dp, struct uio *uio, int *eofp,
193 struct xfs_dirent *dbp, xfs_dir_put_t put);
194int xfs_dir_shortform_replace(struct xfs_da_args *args);
195
196/*
197 * Internal routines when dirsize == XFS_LBSIZE(mp).
198 */
199int xfs_dir_leaf_to_node(struct xfs_da_args *args);
200int xfs_dir_leaf_to_shortform(struct xfs_da_args *args);
201
202/*
203 * Routines used for growing the Btree.
204 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205int xfs_dir_leaf_split(struct xfs_da_state *state,
206 struct xfs_da_state_blk *oldblk,
207 struct xfs_da_state_blk *newblk);
208int xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer,
209 struct xfs_da_args *args, int insertion_index);
210int xfs_dir_leaf_addname(struct xfs_da_args *args);
211int xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer,
212 struct xfs_da_args *args,
213 int *index_found_at);
214int xfs_dir_leaf_remove(struct xfs_trans *trans,
215 struct xfs_dabuf *leaf_buffer,
216 int index_to_remove);
217int 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 */
225int xfs_dir_leaf_toosmall(struct xfs_da_state *state, int *retval);
226void 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 */
233uint xfs_dir_leaf_lasthash(struct xfs_dabuf *bp, int *count);
234int xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp,
235 struct xfs_dabuf *leaf2_bp);
236int xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa);
237int xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa);
238int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);
239
240
241/*
242 * Global data.
243 */
244extern xfs_dahash_t xfs_dir_hash_dot, xfs_dir_hash_dotdot;
245
246#endif /* __XFS_DIR_LEAF_H__ */