1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
4  * Copyright (c) 2013 Red Hat, Inc.
5  * All Rights Reserved.
6  */
7 #ifndef __XFS_DA_BTREE_H__
8 #define	__XFS_DA_BTREE_H__
9 
10 struct xfs_inode;
11 struct xfs_trans;
12 struct zone;
13 struct xfs_dir_ops;
14 
15 /*
16  * Directory/attribute geometry information. There will be one of these for each
17  * data fork type, and it will be passed around via the xfs_da_args. Global
18  * structures will be attached to the xfs_mount.
19  */
20 struct xfs_da_geometry {
21 	int		blksize;	/* da block size in bytes */
22 	int		fsbcount;	/* da block size in filesystem blocks */
23 	uint8_t		fsblog;		/* log2 of _filesystem_ block size */
24 	uint8_t		blklog;		/* log2 of da block size */
25 	uint		node_ents;	/* # of entries in a danode */
26 	int		magicpct;	/* 37% of block size in bytes */
27 	xfs_dablk_t	datablk;	/* blockno of dir data v2 */
28 	xfs_dablk_t	leafblk;	/* blockno of leaf data v2 */
29 	xfs_dablk_t	freeblk;	/* blockno of free data v2 */
30 };
31 
32 /*========================================================================
33  * Btree searching and modification structure definitions.
34  *========================================================================*/
35 
36 /*
37  * Search comparison results
38  */
39 enum xfs_dacmp {
40 	XFS_CMP_DIFFERENT,	/* names are completely different */
41 	XFS_CMP_EXACT,		/* names are exactly the same */
42 	XFS_CMP_CASE		/* names are same but differ in case */
43 };
44 
45 /*
46  * Structure to ease passing around component names.
47  */
48 typedef struct xfs_da_args {
49 	struct xfs_da_geometry *geo;	/* da block geometry */
50 	const uint8_t		*name;		/* string (maybe not NULL terminated) */
51 	int		namelen;	/* length of string (maybe no NULL) */
52 	uint8_t		filetype;	/* filetype of inode for directories */
53 	uint8_t		*value;		/* set of bytes (maybe contain NULLs) */
54 	int		valuelen;	/* length of value */
55 	int		flags;		/* argument flags (eg: ATTR_NOCREATE) */
56 	xfs_dahash_t	hashval;	/* hash value of name */
57 	xfs_ino_t	inumber;	/* input/output inode number */
58 	struct xfs_inode *dp;		/* directory inode to manipulate */
59 	struct xfs_trans *trans;	/* current trans (changes over time) */
60 	xfs_extlen_t	total;		/* total blocks needed, for 1st bmap */
61 	int		whichfork;	/* data or attribute fork */
62 	xfs_dablk_t	blkno;		/* blkno of attr leaf of interest */
63 	int		index;		/* index of attr of interest in blk */
64 	xfs_dablk_t	rmtblkno;	/* remote attr value starting blkno */
65 	int		rmtblkcnt;	/* remote attr value block count */
66 	int		rmtvaluelen;	/* remote attr value length in bytes */
67 	xfs_dablk_t	blkno2;		/* blkno of 2nd attr leaf of interest */
68 	int		index2;		/* index of 2nd attr in blk */
69 	xfs_dablk_t	rmtblkno2;	/* remote attr value starting blkno */
70 	int		rmtblkcnt2;	/* remote attr value block count */
71 	int		rmtvaluelen2;	/* remote attr value length in bytes */
72 	int		op_flags;	/* operation flags */
73 	enum xfs_dacmp	cmpresult;	/* name compare result for lookups */
74 } xfs_da_args_t;
75 
76 /*
77  * Operation flags:
78  */
79 #define XFS_DA_OP_JUSTCHECK	0x0001	/* check for ok with no space */
80 #define XFS_DA_OP_RENAME	0x0002	/* this is an atomic rename op */
81 #define XFS_DA_OP_ADDNAME	0x0004	/* this is an add operation */
82 #define XFS_DA_OP_OKNOENT	0x0008	/* lookup/add op, ENOENT ok, else die */
83 #define XFS_DA_OP_CILOOKUP	0x0010	/* lookup to return CI name if found */
84 
85 #define XFS_DA_OP_FLAGS \
86 	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
87 	{ XFS_DA_OP_RENAME,	"RENAME" }, \
88 	{ XFS_DA_OP_ADDNAME,	"ADDNAME" }, \
89 	{ XFS_DA_OP_OKNOENT,	"OKNOENT" }, \
90 	{ XFS_DA_OP_CILOOKUP,	"CILOOKUP" }
91 
92 /*
93  * Storage for holding state during Btree searches and split/join ops.
94  *
95  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
96  * fanout to the Btree, we can support over 900 million directory blocks,
97  * which is slightly more than enough.
98  */
99 typedef struct xfs_da_state_blk {
100 	struct xfs_buf	*bp;		/* buffer containing block */
101 	xfs_dablk_t	blkno;		/* filesystem blkno of buffer */
102 	xfs_daddr_t	disk_blkno;	/* on-disk blkno (in BBs) of buffer */
103 	int		index;		/* relevant index into block */
104 	xfs_dahash_t	hashval;	/* last hash value in block */
105 	int		magic;		/* blk's magic number, ie: blk type */
106 } xfs_da_state_blk_t;
107 
108 typedef struct xfs_da_state_path {
109 	int			active;		/* number of active levels */
110 	xfs_da_state_blk_t	blk[XFS_DA_NODE_MAXDEPTH];
111 } xfs_da_state_path_t;
112 
113 typedef struct xfs_da_state {
114 	xfs_da_args_t		*args;		/* filename arguments */
115 	struct xfs_mount	*mp;		/* filesystem mount point */
116 	xfs_da_state_path_t	path;		/* search/split paths */
117 	xfs_da_state_path_t	altpath;	/* alternate path for join */
118 	unsigned char		inleaf;		/* insert into 1->lf, 0->splf */
119 	unsigned char		extravalid;	/* T/F: extrablk is in use */
120 	unsigned char		extraafter;	/* T/F: extrablk is after new */
121 	xfs_da_state_blk_t	extrablk;	/* for double-splits on leaves */
122 						/* for dirv2 extrablk is data */
123 } xfs_da_state_t;
124 
125 /*
126  * Utility macros to aid in logging changed structure fields.
127  */
128 #define XFS_DA_LOGOFF(BASE, ADDR)	((char *)(ADDR) - (char *)(BASE))
129 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)	\
130 		(uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
131 		(uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
132 
133 /*
134  * Name ops for directory and/or attr name operations
135  */
136 struct xfs_nameops {
137 	xfs_dahash_t	(*hashname)(struct xfs_name *);
138 	enum xfs_dacmp	(*compname)(struct xfs_da_args *,
139 					const unsigned char *, int);
140 };
141 
142 
143 /*========================================================================
144  * Function prototypes.
145  *========================================================================*/
146 
147 /*
148  * Routines used for growing the Btree.
149  */
150 int	xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
151 			    int level, struct xfs_buf **bpp, int whichfork);
152 int	xfs_da3_split(xfs_da_state_t *state);
153 
154 /*
155  * Routines used for shrinking the Btree.
156  */
157 int	xfs_da3_join(xfs_da_state_t *state);
158 void	xfs_da3_fixhashpath(struct xfs_da_state *state,
159 			    struct xfs_da_state_path *path_to_to_fix);
160 
161 /*
162  * Routines used for finding things in the Btree.
163  */
164 int	xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
165 int	xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
166 					 int forward, int release, int *result);
167 /*
168  * Utility routines.
169  */
170 int	xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
171 				       xfs_da_state_blk_t *new_blk);
172 int	xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
173 			 xfs_dablk_t bno, xfs_daddr_t mappedbno,
174 			 struct xfs_buf **bpp, int which_fork);
175 
176 /*
177  * Utility routines.
178  */
179 int	xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
180 int	xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
181 			      int count);
182 int	xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
183 			      xfs_dablk_t bno, xfs_daddr_t mappedbno,
184 			      struct xfs_buf **bp, int whichfork);
185 int	xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
186 			       xfs_dablk_t bno, xfs_daddr_t mappedbno,
187 			       struct xfs_buf **bpp, int whichfork,
188 			       const struct xfs_buf_ops *ops);
189 int	xfs_da_reada_buf(struct xfs_inode *dp, xfs_dablk_t bno,
190 				xfs_daddr_t mapped_bno, int whichfork,
191 				const struct xfs_buf_ops *ops);
192 int	xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
193 					  struct xfs_buf *dead_buf);
194 
195 uint xfs_da_hashname(const uint8_t *name_string, int name_length);
196 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
197 				const unsigned char *name, int len);
198 
199 
200 xfs_da_state_t *xfs_da_state_alloc(void);
201 void xfs_da_state_free(xfs_da_state_t *state);
202 
203 extern struct kmem_zone *xfs_da_state_zone;
204 extern const struct xfs_nameops xfs_default_nameops;
205 
206 #endif	/* __XFS_DA_BTREE_H__ */
207