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33 #ifndef __XFS_ATTR_LEAF_H__
34 #define __XFS_ATTR_LEAF_H__
37 * Attribute storage layout, internal structure, access macros, etc.
39 * Attribute lists are structured around Btrees where all the data
40 * elements are in the leaf nodes. Attribute names are hashed into an int,
41 * then that int is used as the index into the Btree. Since the hashval
42 * of an attribute name may not be unique, we may have duplicate keys. The
43 * internal links in the Btree are logical block offsets into the file.
47 struct attrlist_cursor_kern;
52 struct xfs_da_state_blk;
56 /*========================================================================
57 * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
58 *========================================================================*/
61 * This is the structure of the leaf nodes in the Btree.
63 * Struct leaf_entry's are packed from the top. Name/values grow from the
64 * bottom 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 name/value area and try again. If we
68 * still don't have enough space, then we have to split the block. The
69 * name/value structs (both local and remote versions) must be 32bit aligned.
71 * Since we have duplicate hash keys, for each key that matches, compare
72 * the actual name string. The root and intermediate node search always
73 * takes the first-in-the-block key match found, so we should only have
74 * to work "forw"ard. If none matches, continue with the "forw"ard leaf
75 * nodes until the hash key changes or the attribute name is found.
77 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
78 * the leaf_entry. The namespaces are independent only because we also look
79 * at the namespace bit when we are looking for a matching attribute name.
81 * We also store a "incomplete" bit in the leaf_entry. It shows that an
82 * attribute is in the middle of being created and should not be shown to
83 * the user if we crash during the time that the bit is set. We clear the
84 * bit when we have finished setting up the attribute. We do this because
85 * we cannot create some large attributes inside a single transaction, and we
86 * need some indication that we weren't finished if we crash in the middle.
88 #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
90 typedef struct xfs_attr_leafblock {
91 struct xfs_attr_leaf_hdr { /* constant-structure header block */
92 xfs_da_blkinfo_t info; /* block type, links, etc. */
93 __uint16_t count; /* count of active leaf_entry's */
94 __uint16_t usedbytes; /* num bytes of names/values stored */
95 __uint16_t firstused; /* first used byte in name area */
96 __uint8_t holes; /* != 0 if blk needs compaction */
98 struct xfs_attr_leaf_map { /* RLE map of free bytes */
99 __uint16_t base; /* base of free region */
100 __uint16_t size; /* length of free region */
101 } freemap[XFS_ATTR_LEAF_MAPSIZE]; /* N largest free regions */
103 struct xfs_attr_leaf_entry { /* sorted on key, not name */
104 xfs_dahash_t hashval; /* hash value of name */
105 __uint16_t nameidx; /* index into buffer of name/value */
106 __uint8_t flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
107 __uint8_t pad2; /* unused pad byte */
108 } entries[1]; /* variable sized array */
109 struct xfs_attr_leaf_name_local {
110 __uint16_t valuelen; /* number of bytes in value */
111 __uint8_t namelen; /* length of name bytes */
112 __uint8_t nameval[1]; /* name/value bytes */
113 } namelist; /* grows from bottom of buf */
114 struct xfs_attr_leaf_name_remote {
115 xfs_dablk_t valueblk; /* block number of value bytes */
116 __uint32_t valuelen; /* number of bytes in value */
117 __uint8_t namelen; /* length of name bytes */
118 __uint8_t name[1]; /* name bytes */
119 } valuelist; /* grows from bottom of buf */
120 } xfs_attr_leafblock_t;
121 typedef struct xfs_attr_leaf_hdr xfs_attr_leaf_hdr_t;
122 typedef struct xfs_attr_leaf_map xfs_attr_leaf_map_t;
123 typedef struct xfs_attr_leaf_entry xfs_attr_leaf_entry_t;
124 typedef struct xfs_attr_leaf_name_local xfs_attr_leaf_name_local_t;
125 typedef struct xfs_attr_leaf_name_remote xfs_attr_leaf_name_remote_t;
128 * Flags used in the leaf_entry[i].flags field.
129 * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
130 * on the system call, they are "or"ed together for various operations.
132 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
133 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
134 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
135 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
136 #define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT)
137 #define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT)
138 #define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT)
139 #define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT)
142 * Alignment for namelist and valuelist entries (since they are mixed
143 * there can be only one alignment value)
145 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
148 * Cast typed pointers for "local" and "remote" name/value structs.
150 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx) \
151 xfs_attr_leaf_name_remote(leafp,idx)
152 static inline xfs_attr_leaf_name_remote_t *
153 xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
155 return (xfs_attr_leaf_name_remote_t *) &((char *)
156 (leafp))[INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT)];
159 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx) \
160 xfs_attr_leaf_name_local(leafp,idx)
161 static inline xfs_attr_leaf_name_local_t *
162 xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
164 return (xfs_attr_leaf_name_local_t *) &((char *)
165 (leafp))[INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT)];
168 #define XFS_ATTR_LEAF_NAME(leafp,idx) xfs_attr_leaf_name(leafp,idx)
169 static inline char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
172 (leafp))[INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT)]);
176 * Calculate total bytes used (including trailing pad for alignment) for
177 * a "local" name/value structure, a "remote" name/value structure, and
178 * a pointer which might be either.
180 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen) \
181 xfs_attr_leaf_entsize_remote(nlen)
182 static inline int xfs_attr_leaf_entsize_remote(int nlen)
184 return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
185 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
188 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen) \
189 xfs_attr_leaf_entsize_local(nlen,vlen)
190 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
192 return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) +
193 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
196 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize) \
197 xfs_attr_leaf_entsize_local_max(bsize)
198 static inline int xfs_attr_leaf_entsize_local_max(int bsize)
200 return (((bsize) >> 1) + ((bsize) >> 2));
204 /*========================================================================
205 * Structure used to pass context around among the routines.
206 *========================================================================*/
208 typedef struct xfs_attr_list_context {
209 struct xfs_inode *dp; /* inode */
210 struct attrlist_cursor_kern *cursor;/* position in list */
211 struct attrlist *alist; /* output buffer */
212 int count; /* num used entries */
213 int dupcnt; /* count dup hashvals seen */
214 int bufsize;/* total buffer size */
215 int firstu; /* first used byte in buffer */
216 int flags; /* from VOP call */
217 int resynch;/* T/F: resynch with cursor */
218 } xfs_attr_list_context_t;
221 * Used to keep a list of "remote value" extents when unlinking an inode.
223 typedef struct xfs_attr_inactive_list {
224 xfs_dablk_t valueblk; /* block number of value bytes */
225 int valuelen; /* number of bytes in value */
226 } xfs_attr_inactive_list_t;
229 /*========================================================================
230 * Function prototypes for the kernel.
231 *========================================================================*/
234 * Internal routines when attribute fork size < XFS_LITINO(mp).
236 void xfs_attr_shortform_create(struct xfs_da_args *args);
237 void xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff);
238 int xfs_attr_shortform_lookup(struct xfs_da_args *args);
239 int xfs_attr_shortform_getvalue(struct xfs_da_args *args);
240 int xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
241 int xfs_attr_shortform_remove(struct xfs_da_args *args);
242 int xfs_attr_shortform_list(struct xfs_attr_list_context *context);
243 int xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
244 int xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes);
248 * Internal routines when attribute fork size == XFS_LBSIZE(mp).
250 int xfs_attr_leaf_to_node(struct xfs_da_args *args);
251 int xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
252 struct xfs_da_args *args, int forkoff);
253 int xfs_attr_leaf_clearflag(struct xfs_da_args *args);
254 int xfs_attr_leaf_setflag(struct xfs_da_args *args);
255 int xfs_attr_leaf_flipflags(xfs_da_args_t *args);
258 * Routines used for growing the Btree.
260 int xfs_attr_leaf_split(struct xfs_da_state *state,
261 struct xfs_da_state_blk *oldblk,
262 struct xfs_da_state_blk *newblk);
263 int xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf,
264 struct xfs_da_args *args);
265 int xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args);
266 int xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer,
267 struct xfs_da_args *args);
268 int xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer,
269 struct xfs_da_args *args);
270 int xfs_attr_leaf_list_int(struct xfs_dabuf *bp,
271 struct xfs_attr_list_context *context);
274 * Routines used for shrinking the Btree.
276 int xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval);
277 void xfs_attr_leaf_unbalance(struct xfs_da_state *state,
278 struct xfs_da_state_blk *drop_blk,
279 struct xfs_da_state_blk *save_blk);
280 int xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp);
285 xfs_dahash_t xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
286 int xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
287 struct xfs_dabuf *leaf2_bp);
288 int xfs_attr_leaf_newentsize(int namelen, int valuelen, int blocksize,
290 int xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp);
292 #endif /* __XFS_ATTR_LEAF_H__ */