include/xfs_attr_leaf.h

   1 /*
   2  * Copyright (c) 2000, 2002 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_ATTR_LEAF_H__
  33 #define __XFS_ATTR_LEAF_H__
  34
  35 /*
  36  * Attribute storage layout, internal structure, access macros, etc.
  37  *
  38  * Attribute lists are structured around Btrees where all the data
  39  * elements are in the leaf nodes.  Attribute names are hashed into an int,
  40  * then that int is used as the index into the Btree.  Since the hashval
  41  * of an attribute name 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
  45 struct attrlist;
  46 struct attrlist_cursor_kern;
  47 struct xfs_dabuf;
  48 struct xfs_da_args;
  49 struct xfs_da_state;
  50 struct xfs_da_state_blk;
  51 struct xfs_inode;
  52 struct xfs_trans;
  53
  54 /*========================================================================
  55  * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
  56  *========================================================================*/
  57
  58 /*
  59  * This is the structure of the leaf nodes in the Btree.
  60  *
  61  * Struct leaf_entry's are packed from the top.  Name/values grow from the
  62  * bottom but are not packed.  The freemap contains run-length-encoded entries
  63  * for the free bytes after the leaf_entry's, but only the N largest such,
  64  * smaller runs are dropped.  When the freemap doesn't show enough space
  65  * for an allocation, we compact the name/value area and try again.  If we
  66  * still don't have enough space, then we have to split the block.  The
  67  * name/value structs (both local and remote versions) must be 32bit aligned.
  68  *
  69  * Since we have duplicate hash keys, for each key that matches, compare
  70  * the actual name string.  The root and intermediate node search always
  71  * takes the first-in-the-block key match found, so we should only have
  72  * to work "forw"ard.  If none matches, continue with the "forw"ard leaf
  73  * nodes until the hash key changes or the attribute name is found.
  74  *
  75  * We store the fact that an attribute is a ROOT versus USER attribute in
  76  * the leaf_entry.  The namespaces are independent only because we also look
  77  * at the root/user bit when we are looking for a matching attribute name.
  78  *
  79  * We also store a "incomplete" bit in the leaf_entry.  It shows that an
  80  * attribute is in the middle of being created and should not be shown to
  81  * the user if we crash during the time that the bit is set.  We clear the
  82  * bit when we have finished setting up the attribute.  We do this because
  83  * we cannot create some large attributes inside a single transaction, and we
  84  * need some indication that we weren't finished if we crash in the middle.
  85  */
  86 #define XFS_ATTR_LEAF_MAPSIZE   3       /* how many freespace slots */
  87
  88 typedef struct xfs_attr_leafblock {
  89         struct xfs_attr_leaf_hdr {      /* constant-structure header block */
  90                 xfs_da_blkinfo_t info;  /* block type, links, etc. */
  91                 __uint16_t count;       /* count of active leaf_entry's */
  92                 __uint16_t usedbytes;   /* num bytes of names/values stored */
  93                 __uint16_t firstused;   /* first used byte in name area */
  94                 __uint8_t  holes;       /* != 0 if blk needs compaction */
  95                 __uint8_t  pad1;
  96                 struct xfs_attr_leaf_map {        /* RLE map of free bytes */
  97                         __uint16_t base;          /* base of free region */
  98                         __uint16_t size;          /* length of free region */
  99                 } freemap[XFS_ATTR_LEAF_MAPSIZE]; /* N largest free regions */
 100         } hdr;
 101         struct xfs_attr_leaf_entry {    /* sorted on key, not name */
 102                 xfs_dahash_t hashval;   /* hash value of name */
 103                 __uint16_t nameidx;     /* index into buffer of name/value */
 104                 __uint8_t flags;        /* LOCAL, ROOT and INCOMPLETE flags */
 105                 __uint8_t pad2;         /* unused pad byte */
 106         } entries[1];                   /* variable sized array */
 107         struct xfs_attr_leaf_name_local {
 108                 __uint16_t valuelen;    /* number of bytes in value */
 109                 __uint8_t namelen;      /* length of name bytes */
 110                 __uint8_t nameval[1];   /* name/value bytes */
 111         } namelist;                     /* grows from bottom of buf */
 112         struct xfs_attr_leaf_name_remote {
 113                 xfs_dablk_t valueblk;   /* block number of value bytes */
 114                 __uint32_t valuelen;    /* number of bytes in value */
 115                 __uint8_t namelen;      /* length of name bytes */
 116                 __uint8_t name[1];      /* name bytes */
 117         } valuelist;                    /* grows from bottom of buf */
 118 } xfs_attr_leafblock_t;
 119 typedef struct xfs_attr_leaf_hdr xfs_attr_leaf_hdr_t;
 120 typedef struct xfs_attr_leaf_map xfs_attr_leaf_map_t;
 121 typedef struct xfs_attr_leaf_entry xfs_attr_leaf_entry_t;
 122 typedef struct xfs_attr_leaf_name_local xfs_attr_leaf_name_local_t;
 123 typedef struct xfs_attr_leaf_name_remote xfs_attr_leaf_name_remote_t;
 124
 125 /*
 126  * Flags used in the leaf_entry[i].flags field.
 127  * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
 128  * on the system call, they are "or"ed together for various operations.
 129  */
 130 #define XFS_ATTR_LOCAL_BIT      0       /* attr is stored locally */
 131 #define XFS_ATTR_ROOT_BIT       1       /* limit access to attr to userid 0 */
 132 #define XFS_ATTR_INCOMPLETE_BIT 7       /* attr in middle of create/delete */
 133 #define XFS_ATTR_LOCAL          (1 << XFS_ATTR_LOCAL_BIT)
 134 #define XFS_ATTR_ROOT           (1 << XFS_ATTR_ROOT_BIT)
 135 #define XFS_ATTR_INCOMPLETE     (1 << XFS_ATTR_INCOMPLETE_BIT)
 136
 137 /*
 138  * Alignment for namelist and valuelist entries (since they are mixed
 139  * there can be only one alignment value)
 140  */
 141 #define XFS_ATTR_LEAF_NAME_ALIGN        ((uint)sizeof(xfs_dablk_t))
 142
 143 /*
 144  * Cast typed pointers for "local" and "remote" name/value structs.
 145  */
 146 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_REMOTE)
 147 xfs_attr_leaf_name_remote_t *
 148 xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx);
 149 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    \
 150         xfs_attr_leaf_name_remote(leafp,idx)
 151 #else
 152 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    /* remote name struct ptr */ \
 153         ((xfs_attr_leaf_name_remote_t *)                \
 154          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 155 #endif
 156 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_LOCAL)
 157 xfs_attr_leaf_name_local_t *
 158 xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx);
 159 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     \
 160         xfs_attr_leaf_name_local(leafp,idx)
 161 #else
 162 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     /* local name struct ptr */ \
 163         ((xfs_attr_leaf_name_local_t *)         \
 164          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 165 #endif
 166 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME)
 167 char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx);
 168 #define XFS_ATTR_LEAF_NAME(leafp,idx)           xfs_attr_leaf_name(leafp,idx)
 169 #else
 170 #define XFS_ATTR_LEAF_NAME(leafp,idx)           /* generic name struct ptr */ \
 171         (&((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 172 #endif
 173
 174 /*
 175  * Calculate total bytes used (including trailing pad for alignment) for
 176  * a "local" name/value structure, a "remote" name/value structure, and
 177  * a pointer which might be either.
 178  */
 179 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_REMOTE)
 180 int xfs_attr_leaf_entsize_remote(int nlen);
 181 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      \
 182         xfs_attr_leaf_entsize_remote(nlen)
 183 #else
 184 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      /* space for remote struct */ \
 185         (((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
 186           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 187 #endif
 188 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL)
 189 int xfs_attr_leaf_entsize_local(int nlen, int vlen);
 190 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  \
 191         xfs_attr_leaf_entsize_local(nlen,vlen)
 192 #else
 193 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  /* space for local struct */ \
 194         (((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + \
 195           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 196 #endif
 197 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX)
 198 int xfs_attr_leaf_entsize_local_max(int bsize);
 199 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  \
 200         xfs_attr_leaf_entsize_local_max(bsize)
 201 #else
 202 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  /* max local struct size */ \
 203         (((bsize) >> 1) + ((bsize) >> 2))
 204 #endif
 205
 206
 207 /*========================================================================
 208  * Structure used to pass context around among the routines.
 209  *========================================================================*/
 210
 211 typedef struct xfs_attr_list_context {
 212         struct xfs_inode                *dp;    /* inode */
 213         struct attrlist_cursor_kern     *cursor;/* position in list */
 214         struct attrlist                 *alist; /* output buffer */
 215         int                             count;  /* num used entries */
 216         int                             dupcnt; /* count dup hashvals seen */
 217         int                             bufsize;/* total buffer size */
 218         int                             firstu; /* first used byte in buffer */
 219         int                             flags;  /* from VOP call */
 220         int                             resynch;/* T/F: resynch with cursor */
 221 } xfs_attr_list_context_t;
 222
 223 /*
 224  * Used to keep a list of "remote value" extents when unlinking an inode.
 225  */
 226 typedef struct xfs_attr_inactive_list {
 227         xfs_dablk_t     valueblk;       /* block number of value bytes */
 228         int             valuelen;       /* number of bytes in value */
 229 } xfs_attr_inactive_list_t;
 230
 231
 232 /*========================================================================
 233  * Function prototypes for the kernel.
 234  *========================================================================*/
 235
 236 /*
 237  * Internal routines when dirsize < XFS_LITINO(mp).
 238  */
 239 int     xfs_attr_shortform_create(struct xfs_da_args *args);
 240 int     xfs_attr_shortform_add(struct xfs_da_args *add);
 241 int     xfs_attr_shortform_lookup(struct xfs_da_args *args);
 242 int     xfs_attr_shortform_getvalue(struct xfs_da_args *args);
 243 int     xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
 244 int     xfs_attr_shortform_remove(struct xfs_da_args *remove);
 245 int     xfs_attr_shortform_list(struct xfs_attr_list_context *context);
 246 int     xfs_attr_shortform_replace(struct xfs_da_args *args);
 247 int     xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
 248
 249 /*
 250  * Internal routines when dirsize == XFS_LBSIZE(mp).
 251  */
 252 int     xfs_attr_leaf_to_node(struct xfs_da_args *args);
 253 int     xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
 254                                           struct xfs_da_args *args);
 255 int     xfs_attr_leaf_clearflag(struct xfs_da_args *args);
 256 int     xfs_attr_leaf_setflag(struct xfs_da_args *args);
 257 int     xfs_attr_leaf_flipflags(xfs_da_args_t *args);
 258
 259 /*
 260  * Routines used for growing the Btree.
 261  */
 262 int     xfs_attr_leaf_create(struct xfs_da_args *args, xfs_dablk_t which_block,
 263                                     struct xfs_dabuf **bpp);
 264 int     xfs_attr_leaf_split(struct xfs_da_state *state,
 265                                    struct xfs_da_state_blk *oldblk,
 266                                    struct xfs_da_state_blk *newblk);
 267 int     xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf,
 268                                         struct xfs_da_args *args);
 269 int     xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args);
 270 int     xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer,
 271                                  struct xfs_da_args *args);
 272 int     xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer,
 273                                     struct xfs_da_args *args);
 274 int     xfs_attr_leaf_list_int(struct xfs_dabuf *bp,
 275                                       struct xfs_attr_list_context *context);
 276
 277 /*
 278  * Routines used for shrinking the Btree.
 279  */
 280 int     xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval);
 281 void    xfs_attr_leaf_unbalance(struct xfs_da_state *state,
 282                                        struct xfs_da_state_blk *drop_blk,
 283                                        struct xfs_da_state_blk *save_blk);
 284 int     xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp);
 285 int     xfs_attr_node_inactive(struct xfs_trans **trans, struct xfs_inode *dp,
 286                                       struct xfs_dabuf *bp, int level);
 287 int     xfs_attr_leaf_inactive(struct xfs_trans **trans, struct xfs_inode *dp,
 288                                       struct xfs_dabuf *bp);
 289 int     xfs_attr_leaf_freextent(struct xfs_trans **trans, struct xfs_inode *dp,
 290                                        xfs_dablk_t blkno, int blkcnt);
 291
 292 /*
 293  * Utility routines.
 294  */
 295 xfs_dahash_t    xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
 296 int     xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
 297                                    struct xfs_dabuf *leaf2_bp);
 298 int     xfs_attr_leaf_newentsize(struct xfs_da_args *args, int blocksize,
 299                                         int *local);
 300 int     xfs_attr_leaf_entsize(struct xfs_attr_leafblock *leaf, int index);
 301 int     xfs_attr_put_listent(struct xfs_attr_list_context *context,
 302                              int ns, char *name, int namelen, int valuelen);
 303 int     xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp);
 304
 305 #endif  /* __XFS_ATTR_LEAF_H__ */