2 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 #ifndef __XFS_ATTR_LEAF_H__
19 #define __XFS_ATTR_LEAF_H__
22 * Attribute storage layout, internal structure, access macros, etc.
24 * Attribute lists are structured around Btrees where all the data
25 * elements are in the leaf nodes. Attribute names are hashed into an int,
26 * then that int is used as the index into the Btree. Since the hashval
27 * of an attribute name may not be unique, we may have duplicate keys. The
28 * internal links in the Btree are logical block offsets into the file.
32 struct attrlist_cursor_kern
;
33 struct xfs_attr_list_context
;
36 struct xfs_da_state_blk
;
40 /*========================================================================
41 * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
42 *========================================================================*/
45 * This is the structure of the leaf nodes in the Btree.
47 * Struct leaf_entry's are packed from the top. Name/values grow from the
48 * bottom but are not packed. The freemap contains run-length-encoded entries
49 * for the free bytes after the leaf_entry's, but only the N largest such,
50 * smaller runs are dropped. When the freemap doesn't show enough space
51 * for an allocation, we compact the name/value area and try again. If we
52 * still don't have enough space, then we have to split the block. The
53 * name/value structs (both local and remote versions) must be 32bit aligned.
55 * Since we have duplicate hash keys, for each key that matches, compare
56 * the actual name string. The root and intermediate node search always
57 * takes the first-in-the-block key match found, so we should only have
58 * to work "forw"ard. If none matches, continue with the "forw"ard leaf
59 * nodes until the hash key changes or the attribute name is found.
61 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
62 * the leaf_entry. The namespaces are independent only because we also look
63 * at the namespace bit when we are looking for a matching attribute name.
65 * We also store an "incomplete" bit in the leaf_entry. It shows that an
66 * attribute is in the middle of being created and should not be shown to
67 * the user if we crash during the time that the bit is set. We clear the
68 * bit when we have finished setting up the attribute. We do this because
69 * we cannot create some large attributes inside a single transaction, and we
70 * need some indication that we weren't finished if we crash in the middle.
72 #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
74 typedef struct xfs_attr_leaf_map
{ /* RLE map of free bytes */
75 __be16 base
; /* base of free region */
76 __be16 size
; /* length of free region */
77 } xfs_attr_leaf_map_t
;
79 typedef struct xfs_attr_leaf_hdr
{ /* constant-structure header block */
80 xfs_da_blkinfo_t info
; /* block type, links, etc. */
81 __be16 count
; /* count of active leaf_entry's */
82 __be16 usedbytes
; /* num bytes of names/values stored */
83 __be16 firstused
; /* first used byte in name area */
84 __u8 holes
; /* != 0 if blk needs compaction */
86 xfs_attr_leaf_map_t freemap
[XFS_ATTR_LEAF_MAPSIZE
];
87 /* N largest free regions */
88 } xfs_attr_leaf_hdr_t
;
90 typedef struct xfs_attr_leaf_entry
{ /* sorted on key, not name */
91 __be32 hashval
; /* hash value of name */
92 __be16 nameidx
; /* index into buffer of name/value */
93 __u8 flags
; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
94 __u8 pad2
; /* unused pad byte */
95 } xfs_attr_leaf_entry_t
;
97 typedef struct xfs_attr_leaf_name_local
{
98 __be16 valuelen
; /* number of bytes in value */
99 __u8 namelen
; /* length of name bytes */
100 __u8 nameval
[1]; /* name/value bytes */
101 } xfs_attr_leaf_name_local_t
;
103 typedef struct xfs_attr_leaf_name_remote
{
104 __be32 valueblk
; /* block number of value bytes */
105 __be32 valuelen
; /* number of bytes in value */
106 __u8 namelen
; /* length of name bytes */
107 __u8 name
[1]; /* name bytes */
108 } xfs_attr_leaf_name_remote_t
;
110 typedef struct xfs_attr_leafblock
{
111 xfs_attr_leaf_hdr_t hdr
; /* constant-structure header block */
112 xfs_attr_leaf_entry_t entries
[1]; /* sorted on key, not name */
113 xfs_attr_leaf_name_local_t namelist
; /* grows from bottom of buf */
114 xfs_attr_leaf_name_remote_t valuelist
; /* grows from bottom of buf */
115 } xfs_attr_leafblock_t
;
118 * Flags used in the leaf_entry[i].flags field.
119 * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
120 * on the system call, they are "or"ed together for various operations.
122 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
123 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
124 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
125 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
126 #define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT)
127 #define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT)
128 #define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT)
129 #define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT)
132 * Conversion macros for converting namespace bits from argument flags
135 #define XFS_ATTR_NSP_ARGS_MASK (ATTR_ROOT | ATTR_SECURE)
136 #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
137 #define XFS_ATTR_NSP_ONDISK(flags) ((flags) & XFS_ATTR_NSP_ONDISK_MASK)
138 #define XFS_ATTR_NSP_ARGS(flags) ((flags) & XFS_ATTR_NSP_ARGS_MASK)
139 #define XFS_ATTR_NSP_ARGS_TO_ONDISK(x) (((x) & ATTR_ROOT ? XFS_ATTR_ROOT : 0) |\
140 ((x) & ATTR_SECURE ? XFS_ATTR_SECURE : 0))
141 #define XFS_ATTR_NSP_ONDISK_TO_ARGS(x) (((x) & XFS_ATTR_ROOT ? ATTR_ROOT : 0) |\
142 ((x) & XFS_ATTR_SECURE ? ATTR_SECURE : 0))
145 * Alignment for namelist and valuelist entries (since they are mixed
146 * there can be only one alignment value)
148 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
151 * Cast typed pointers for "local" and "remote" name/value structs.
153 static inline xfs_attr_leaf_name_remote_t
*
154 xfs_attr_leaf_name_remote(xfs_attr_leafblock_t
*leafp
, int idx
)
156 return (xfs_attr_leaf_name_remote_t
*)
157 &((char *)leafp
)[be16_to_cpu(leafp
->entries
[idx
].nameidx
)];
160 static inline xfs_attr_leaf_name_local_t
*
161 xfs_attr_leaf_name_local(xfs_attr_leafblock_t
*leafp
, int idx
)
163 return (xfs_attr_leaf_name_local_t
*)
164 &((char *)leafp
)[be16_to_cpu(leafp
->entries
[idx
].nameidx
)];
167 static inline char *xfs_attr_leaf_name(xfs_attr_leafblock_t
*leafp
, int idx
)
169 return &((char *)leafp
)[be16_to_cpu(leafp
->entries
[idx
].nameidx
)];
173 * Calculate total bytes used (including trailing pad for alignment) for
174 * a "local" name/value structure, a "remote" name/value structure, and
175 * a pointer which might be either.
177 static inline int xfs_attr_leaf_entsize_remote(int nlen
)
179 return ((uint
)sizeof(xfs_attr_leaf_name_remote_t
) - 1 + (nlen
) + \
180 XFS_ATTR_LEAF_NAME_ALIGN
- 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN
- 1);
183 static inline int xfs_attr_leaf_entsize_local(int nlen
, int vlen
)
185 return ((uint
)sizeof(xfs_attr_leaf_name_local_t
) - 1 + (nlen
) + (vlen
) +
186 XFS_ATTR_LEAF_NAME_ALIGN
- 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN
- 1);
189 static inline int xfs_attr_leaf_entsize_local_max(int bsize
)
191 return (((bsize
) >> 1) + ((bsize
) >> 2));
195 * Used to keep a list of "remote value" extents when unlinking an inode.
197 typedef struct xfs_attr_inactive_list
{
198 xfs_dablk_t valueblk
; /* block number of value bytes */
199 int valuelen
; /* number of bytes in value */
200 } xfs_attr_inactive_list_t
;
203 /*========================================================================
204 * Function prototypes for the kernel.
205 *========================================================================*/
208 * Internal routines when attribute fork size < XFS_LITINO(mp).
210 void xfs_attr_shortform_create(struct xfs_da_args
*args
);
211 void xfs_attr_shortform_add(struct xfs_da_args
*args
, int forkoff
);
212 int xfs_attr_shortform_lookup(struct xfs_da_args
*args
);
213 int xfs_attr_shortform_getvalue(struct xfs_da_args
*args
);
214 int xfs_attr_shortform_to_leaf(struct xfs_da_args
*args
);
215 int xfs_attr_shortform_remove(struct xfs_da_args
*args
);
216 int xfs_attr_shortform_list(struct xfs_attr_list_context
*context
);
217 int xfs_attr_shortform_allfit(struct xfs_buf
*bp
, struct xfs_inode
*dp
);
218 int xfs_attr_shortform_bytesfit(xfs_inode_t
*dp
, int bytes
);
222 * Internal routines when attribute fork size == XFS_LBSIZE(mp).
224 int xfs_attr_leaf_to_node(struct xfs_da_args
*args
);
225 int xfs_attr_leaf_to_shortform(struct xfs_buf
*bp
,
226 struct xfs_da_args
*args
, int forkoff
);
227 int xfs_attr_leaf_clearflag(struct xfs_da_args
*args
);
228 int xfs_attr_leaf_setflag(struct xfs_da_args
*args
);
229 int xfs_attr_leaf_flipflags(xfs_da_args_t
*args
);
232 * Routines used for growing the Btree.
234 int xfs_attr_leaf_split(struct xfs_da_state
*state
,
235 struct xfs_da_state_blk
*oldblk
,
236 struct xfs_da_state_blk
*newblk
);
237 int xfs_attr_leaf_lookup_int(struct xfs_buf
*leaf
,
238 struct xfs_da_args
*args
);
239 int xfs_attr_leaf_getvalue(struct xfs_buf
*bp
, struct xfs_da_args
*args
);
240 int xfs_attr_leaf_add(struct xfs_buf
*leaf_buffer
,
241 struct xfs_da_args
*args
);
242 int xfs_attr_leaf_remove(struct xfs_buf
*leaf_buffer
,
243 struct xfs_da_args
*args
);
244 int xfs_attr_leaf_list_int(struct xfs_buf
*bp
,
245 struct xfs_attr_list_context
*context
);
248 * Routines used for shrinking the Btree.
250 int xfs_attr_leaf_toosmall(struct xfs_da_state
*state
, int *retval
);
251 void xfs_attr_leaf_unbalance(struct xfs_da_state
*state
,
252 struct xfs_da_state_blk
*drop_blk
,
253 struct xfs_da_state_blk
*save_blk
);
254 int xfs_attr_root_inactive(struct xfs_trans
**trans
, struct xfs_inode
*dp
);
259 xfs_dahash_t
xfs_attr_leaf_lasthash(struct xfs_buf
*bp
, int *count
);
260 int xfs_attr_leaf_order(struct xfs_buf
*leaf1_bp
,
261 struct xfs_buf
*leaf2_bp
);
262 int xfs_attr_leaf_newentsize(int namelen
, int valuelen
, int blocksize
,
264 #endif /* __XFS_ATTR_LEAF_H__ */