1/* 2 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc. 3 * All Rights Reserved. 4 * 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. 8 * 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. 13 * 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 17 */ 18#ifndef __XFS_ATTR_LEAF_H__ 19#define __XFS_ATTR_LEAF_H__ 20 21/* 22 * Attribute storage layout, internal structure, access macros, etc. 23 * 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. 29 */ 30 31struct attrlist; 32struct attrlist_cursor_kern; 33struct attrnames; 34struct xfs_dabuf; 35struct xfs_da_args; 36struct xfs_da_state; 37struct xfs_da_state_blk; 38struct xfs_inode; 39struct xfs_trans; 40 41/*======================================================================== 42 * Attribute structure when equal to XFS_LBSIZE(mp) bytes. 43 *========================================================================*/ 44 45/* 46 * This is the structure of the leaf nodes in the Btree. 47 * 48 * Struct leaf_entry's are packed from the top. Name/values grow from the 49 * bottom but are not packed. The freemap contains run-length-encoded entries 50 * for the free bytes after the leaf_entry's, but only the N largest such, 51 * smaller runs are dropped. When the freemap doesn't show enough space 52 * for an allocation, we compact the name/value area and try again. If we 53 * still don't have enough space, then we have to split the block. The 54 * name/value structs (both local and remote versions) must be 32bit aligned. 55 * 56 * Since we have duplicate hash keys, for each key that matches, compare 57 * the actual name string. The root and intermediate node search always 58 * takes the first-in-the-block key match found, so we should only have 59 * to work "forw"ard. If none matches, continue with the "forw"ard leaf 60 * nodes until the hash key changes or the attribute name is found. 61 * 62 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in 63 * the leaf_entry. The namespaces are independent only because we also look 64 * at the namespace bit when we are looking for a matching attribute name. 65 * 66 * We also store an "incomplete" bit in the leaf_entry. It shows that an 67 * attribute is in the middle of being created and should not be shown to 68 * the user if we crash during the time that the bit is set. We clear the 69 * bit when we have finished setting up the attribute. We do this because 70 * we cannot create some large attributes inside a single transaction, and we 71 * need some indication that we weren't finished if we crash in the middle. 72 */ 73#define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */ 74 75typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ 76 __be16 base; /* base of free region */ 77 __be16 size; /* length of free region */ 78} xfs_attr_leaf_map_t; 79 80typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */ 81 xfs_da_blkinfo_t info; /* block type, links, etc. */ 82 __be16 count; /* count of active leaf_entry's */ 83 __be16 usedbytes; /* num bytes of names/values stored */ 84 __be16 firstused; /* first used byte in name area */ 85 __u8 holes; /* != 0 if blk needs compaction */ 86 __u8 pad1; 87 xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE]; 88 /* N largest free regions */ 89} xfs_attr_leaf_hdr_t; 90 91typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ 92 __be32 hashval; /* hash value of name */ 93 __be16 nameidx; /* index into buffer of name/value */ 94 __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */ 95 __u8 pad2; /* unused pad byte */ 96} xfs_attr_leaf_entry_t; 97 98typedef struct xfs_attr_leaf_name_local { 99 __be16 valuelen; /* number of bytes in value */ 100 __u8 namelen; /* length of name bytes */ 101 __u8 nameval[1]; /* name/value bytes */ 102} xfs_attr_leaf_name_local_t; 103 104typedef struct xfs_attr_leaf_name_remote { 105 __be32 valueblk; /* block number of value bytes */ 106 __be32 valuelen; /* number of bytes in value */ 107 __u8 namelen; /* length of name bytes */ 108 __u8 name[1]; /* name bytes */ 109} xfs_attr_leaf_name_remote_t; 110 111typedef struct xfs_attr_leafblock { 112 xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ 113 xfs_attr_leaf_entry_t entries[1]; /* sorted on key, not name */ 114 xfs_attr_leaf_name_local_t namelist; /* grows from bottom of buf */ 115 xfs_attr_leaf_name_remote_t valuelist; /* grows from bottom of buf */ 116} xfs_attr_leafblock_t; 117 118/* 119 * Flags used in the leaf_entry[i].flags field. 120 * NOTE: the INCOMPLETE bit must not collide with the flags bits specified 121 * on the system call, they are "or"ed together for various operations. 122 */ 123#define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */ 124#define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */ 125#define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */ 126#define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ 127#define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT) 128#define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT) 129#define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT) 130#define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT) 131 132/* 133 * Alignment for namelist and valuelist entries (since they are mixed 134 * there can be only one alignment value) 135 */ 136#define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) 137 138/* 139 * Cast typed pointers for "local" and "remote" name/value structs. 140 */ 141#define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx) \ 142 xfs_attr_leaf_name_remote(leafp,idx) 143static inline xfs_attr_leaf_name_remote_t * 144xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) 145{ 146 return (xfs_attr_leaf_name_remote_t *) 147 &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 148} 149 150#define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx) \ 151 xfs_attr_leaf_name_local(leafp,idx) 152static inline xfs_attr_leaf_name_local_t * 153xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) 154{ 155 return (xfs_attr_leaf_name_local_t *) 156 &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 157} 158 159#define XFS_ATTR_LEAF_NAME(leafp,idx) \ 160 xfs_attr_leaf_name(leafp,idx) 161static inline char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx) 162{ 163 return &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 164} 165 166/* 167 * Calculate total bytes used (including trailing pad for alignment) for 168 * a "local" name/value structure, a "remote" name/value structure, and 169 * a pointer which might be either. 170 */ 171#define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen) \ 172 xfs_attr_leaf_entsize_remote(nlen) 173static inline int xfs_attr_leaf_entsize_remote(int nlen) 174{ 175 return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \ 176 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1); 177} 178 179#define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen) \ 180 xfs_attr_leaf_entsize_local(nlen,vlen) 181static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) 182{ 183 return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + 184 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1); 185} 186 187#define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize) \ 188 xfs_attr_leaf_entsize_local_max(bsize) 189static inline int xfs_attr_leaf_entsize_local_max(int bsize) 190{ 191 return (((bsize) >> 1) + ((bsize) >> 2)); 192} 193 194 195/*======================================================================== 196 * Structure used to pass context around among the routines. 197 *========================================================================*/ 198 199typedef struct xfs_attr_list_context { 200 struct xfs_inode *dp; /* inode */ 201 struct attrlist_cursor_kern *cursor;/* position in list */ 202 struct attrlist *alist; /* output buffer */ 203 int count; /* num used entries */ 204 int dupcnt; /* count dup hashvals seen */ 205 int bufsize;/* total buffer size */ 206 int firstu; /* first used byte in buffer */ 207 int flags; /* from VOP call */ 208 int resynch;/* T/F: resynch with cursor */ 209} xfs_attr_list_context_t; 210 211/* 212 * Used to keep a list of "remote value" extents when unlinking an inode. 213 */ 214typedef struct xfs_attr_inactive_list { 215 xfs_dablk_t valueblk; /* block number of value bytes */ 216 int valuelen; /* number of bytes in value */ 217} xfs_attr_inactive_list_t; 218 219 220/*======================================================================== 221 * Function prototypes for the kernel. 222 *========================================================================*/ 223 224/* 225 * Internal routines when attribute fork size < XFS_LITINO(mp). 226 */ 227void xfs_attr_shortform_create(struct xfs_da_args *args); 228void xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff); 229int xfs_attr_shortform_lookup(struct xfs_da_args *args); 230int xfs_attr_shortform_to_leaf(struct xfs_da_args *args); 231int xfs_attr_shortform_remove(struct xfs_da_args *args); 232int xfs_attr_shortform_list(struct xfs_attr_list_context *context); 233int xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp); 234int xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes); 235 236 237/* 238 * Internal routines when attribute fork size == XFS_LBSIZE(mp). 239 */ 240int xfs_attr_leaf_to_node(struct xfs_da_args *args); 241int xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp, 242 struct xfs_da_args *args, int forkoff); 243int xfs_attr_leaf_clearflag(struct xfs_da_args *args); 244int xfs_attr_leaf_setflag(struct xfs_da_args *args); 245int xfs_attr_leaf_flipflags(xfs_da_args_t *args); 246 247/* 248 * Routines used for growing the Btree. 249 */ 250int xfs_attr_leaf_split(struct xfs_da_state *state, 251 struct xfs_da_state_blk *oldblk, 252 struct xfs_da_state_blk *newblk); 253int xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf, 254 struct xfs_da_args *args); 255int xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args); 256int xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer, 257 struct xfs_da_args *args); 258int xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer, 259 struct xfs_da_args *args); 260int xfs_attr_leaf_list_int(struct xfs_dabuf *bp, 261 struct xfs_attr_list_context *context); 262 263/* 264 * Routines used for shrinking the Btree. 265 */ 266int xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval); 267void xfs_attr_leaf_unbalance(struct xfs_da_state *state, 268 struct xfs_da_state_blk *drop_blk, 269 struct xfs_da_state_blk *save_blk); 270int xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp); 271 272/* 273 * Utility routines. 274 */ 275xfs_dahash_t xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count); 276int xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp, 277 struct xfs_dabuf *leaf2_bp); 278int xfs_attr_leaf_newentsize(int namelen, int valuelen, int blocksize, 279 int *local); 280int xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp); 281 282#endif /* __XFS_ATTR_LEAF_H__ */ 283