fs/xfs/xfs_attr_leaf.h

   1 /*
   2  * Copyright (c) 2000, 2002-2003 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 attrnames;
  48 struct xfs_dabuf;
  49 struct xfs_da_args;
  50 struct xfs_da_state;
  51 struct xfs_da_state_blk;
  52 struct xfs_inode;
  53 struct xfs_trans;
  54
  55 /*========================================================================
  56  * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
  57  *========================================================================*/
  58
  59 /*
  60  * This is the structure of the leaf nodes in the Btree.
  61  *
  62  * Struct leaf_entry's are packed from the top.  Name/values grow from the
  63  * bottom but are not packed.  The freemap contains run-length-encoded entries
  64  * for the free bytes after the leaf_entry's, but only the N largest such,
  65  * smaller runs are dropped.  When the freemap doesn't show enough space
  66  * for an allocation, we compact the name/value area and try again.  If we
  67  * still don't have enough space, then we have to split the block.  The
  68  * name/value structs (both local and remote versions) must be 32bit aligned.
  69  *
  70  * Since we have duplicate hash keys, for each key that matches, compare
  71  * the actual name string.  The root and intermediate node search always
  72  * takes the first-in-the-block key match found, so we should only have
  73  * to work "forw"ard.  If none matches, continue with the "forw"ard leaf
  74  * nodes until the hash key changes or the attribute name is found.
  75  *
  76  * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
  77  * the leaf_entry.  The namespaces are independent only because we also look
  78  * at the namespace bit when we are looking for a matching attribute name.
  79  *
  80  * We also store a "incomplete" bit in the leaf_entry.  It shows that an
  81  * attribute is in the middle of being created and should not be shown to
  82  * the user if we crash during the time that the bit is set.  We clear the
  83  * bit when we have finished setting up the attribute.  We do this because
  84  * we cannot create some large attributes inside a single transaction, and we
  85  * need some indication that we weren't finished if we crash in the middle.
  86  */
  87 #define XFS_ATTR_LEAF_MAPSIZE   3       /* how many freespace slots */
  88
  89 typedef struct xfs_attr_leafblock {
  90         struct xfs_attr_leaf_hdr {      /* constant-structure header block */
  91                 xfs_da_blkinfo_t info;  /* block type, links, etc. */
  92                 __uint16_t count;       /* count of active leaf_entry's */
  93                 __uint16_t usedbytes;   /* num bytes of names/values stored */
  94                 __uint16_t firstused;   /* first used byte in name area */
  95                 __uint8_t  holes;       /* != 0 if blk needs compaction */
  96                 __uint8_t  pad1;
  97                 struct xfs_attr_leaf_map {        /* RLE map of free bytes */
  98                         __uint16_t base;          /* base of free region */
  99                         __uint16_t size;          /* length of free region */
 100                 } freemap[XFS_ATTR_LEAF_MAPSIZE]; /* N largest free regions */
 101         } hdr;
 102         struct xfs_attr_leaf_entry {    /* sorted on key, not name */
 103                 xfs_dahash_t hashval;   /* hash value of name */
 104                 __uint16_t nameidx;     /* index into buffer of name/value */
 105                 __uint8_t flags;        /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
 106                 __uint8_t pad2;         /* unused pad byte */
 107         } entries[1];                   /* variable sized array */
 108         struct xfs_attr_leaf_name_local {
 109                 __uint16_t valuelen;    /* number of bytes in value */
 110                 __uint8_t namelen;      /* length of name bytes */
 111                 __uint8_t nameval[1];   /* name/value bytes */
 112         } namelist;                     /* grows from bottom of buf */
 113         struct xfs_attr_leaf_name_remote {
 114                 xfs_dablk_t valueblk;   /* block number of value bytes */
 115                 __uint32_t valuelen;    /* number of bytes in value */
 116                 __uint8_t namelen;      /* length of name bytes */
 117                 __uint8_t name[1];      /* name bytes */
 118         } valuelist;                    /* grows from bottom of buf */
 119 } xfs_attr_leafblock_t;
 120 typedef struct xfs_attr_leaf_hdr xfs_attr_leaf_hdr_t;
 121 typedef struct xfs_attr_leaf_map xfs_attr_leaf_map_t;
 122 typedef struct xfs_attr_leaf_entry xfs_attr_leaf_entry_t;
 123 typedef struct xfs_attr_leaf_name_local xfs_attr_leaf_name_local_t;
 124 typedef struct xfs_attr_leaf_name_remote xfs_attr_leaf_name_remote_t;
 125
 126 /*
 127  * Flags used in the leaf_entry[i].flags field.
 128  * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
 129  * on the system call, they are "or"ed together for various operations.
 130  */
 131 #define XFS_ATTR_LOCAL_BIT      0       /* attr is stored locally */
 132 #define XFS_ATTR_ROOT_BIT       1       /* limit access to trusted attrs */
 133 #define XFS_ATTR_SECURE_BIT     2       /* limit access to secure attrs */
 134 #define XFS_ATTR_INCOMPLETE_BIT 7       /* attr in middle of create/delete */
 135 #define XFS_ATTR_LOCAL          (1 << XFS_ATTR_LOCAL_BIT)
 136 #define XFS_ATTR_ROOT           (1 << XFS_ATTR_ROOT_BIT)
 137 #define XFS_ATTR_SECURE         (1 << XFS_ATTR_SECURE_BIT)
 138 #define XFS_ATTR_INCOMPLETE     (1 << XFS_ATTR_INCOMPLETE_BIT)
 139
 140 /*
 141  * Alignment for namelist and valuelist entries (since they are mixed
 142  * there can be only one alignment value)
 143  */
 144 #define XFS_ATTR_LEAF_NAME_ALIGN        ((uint)sizeof(xfs_dablk_t))
 145
 146 /*
 147  * Cast typed pointers for "local" and "remote" name/value structs.
 148  */
 149 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_REMOTE)
 150 xfs_attr_leaf_name_remote_t *
 151 xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx);
 152 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    \
 153         xfs_attr_leaf_name_remote(leafp,idx)
 154 #else
 155 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    /* remote name struct ptr */ \
 156         ((xfs_attr_leaf_name_remote_t *)                \
 157          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 158 #endif
 159 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_LOCAL)
 160 xfs_attr_leaf_name_local_t *
 161 xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx);
 162 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     \
 163         xfs_attr_leaf_name_local(leafp,idx)
 164 #else
 165 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     /* local name struct ptr */ \
 166         ((xfs_attr_leaf_name_local_t *)         \
 167          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 168 #endif
 169 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME)
 170 char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx);
 171 #define XFS_ATTR_LEAF_NAME(leafp,idx)           xfs_attr_leaf_name(leafp,idx)
 172 #else
 173 #define XFS_ATTR_LEAF_NAME(leafp,idx)           /* generic name struct ptr */ \
 174         (&((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 175 #endif
 176
 177 /*
 178  * Calculate total bytes used (including trailing pad for alignment) for
 179  * a "local" name/value structure, a "remote" name/value structure, and
 180  * a pointer which might be either.
 181  */
 182 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_REMOTE)
 183 int xfs_attr_leaf_entsize_remote(int nlen);
 184 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      \
 185         xfs_attr_leaf_entsize_remote(nlen)
 186 #else
 187 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      /* space for remote struct */ \
 188         (((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
 189           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 190 #endif
 191 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL)
 192 int xfs_attr_leaf_entsize_local(int nlen, int vlen);
 193 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  \
 194         xfs_attr_leaf_entsize_local(nlen,vlen)
 195 #else
 196 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  /* space for local struct */ \
 197         (((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + \
 198           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 199 #endif
 200 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX)
 201 int xfs_attr_leaf_entsize_local_max(int bsize);
 202 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  \
 203         xfs_attr_leaf_entsize_local_max(bsize)
 204 #else
 205 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  /* max local struct size */ \
 206         (((bsize) >> 1) + ((bsize) >> 2))
 207 #endif
 208
 209
 210 /*========================================================================
 211  * Structure used to pass context around among the routines.
 212  *========================================================================*/
 213
 214 typedef struct xfs_attr_list_context {
 215         struct xfs_inode                *dp;    /* inode */
 216         struct attrlist_cursor_kern     *cursor;/* position in list */
 217         struct attrlist                 *alist; /* output buffer */
 218         int                             count;  /* num used entries */
 219         int                             dupcnt; /* count dup hashvals seen */
 220         int                             bufsize;/* total buffer size */
 221         int                             firstu; /* first used byte in buffer */
 222         int                             flags;  /* from VOP call */
 223         int                             resynch;/* T/F: resynch with cursor */
 224 } xfs_attr_list_context_t;
 225
 226 /*
 227  * Used to keep a list of "remote value" extents when unlinking an inode.
 228  */
 229 typedef struct xfs_attr_inactive_list {
 230         xfs_dablk_t     valueblk;       /* block number of value bytes */
 231         int             valuelen;       /* number of bytes in value */
 232 } xfs_attr_inactive_list_t;
 233
 234
 235 /*========================================================================
 236  * Function prototypes for the kernel.
 237  *========================================================================*/
 238
 239 /*
 240  * Internal routines when dirsize < XFS_LITINO(mp).
 241  */
 242 int     xfs_attr_shortform_create(struct xfs_da_args *args);
 243 int     xfs_attr_shortform_add(struct xfs_da_args *add);
 244 int     xfs_attr_shortform_lookup(struct xfs_da_args *args);
 245 int     xfs_attr_shortform_getvalue(struct xfs_da_args *args);
 246 int     xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
 247 int     xfs_attr_shortform_remove(struct xfs_da_args *remove);
 248 int     xfs_attr_shortform_list(struct xfs_attr_list_context *context);
 249 int     xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
 250
 251 /*
 252  * Internal routines when dirsize == XFS_LBSIZE(mp).
 253  */
 254 int     xfs_attr_leaf_to_node(struct xfs_da_args *args);
 255 int     xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
 256                                           struct xfs_da_args *args);
 257 int     xfs_attr_leaf_clearflag(struct xfs_da_args *args);
 258 int     xfs_attr_leaf_setflag(struct xfs_da_args *args);
 259 int     xfs_attr_leaf_flipflags(xfs_da_args_t *args);
 260
 261 /*
 262  * Routines used for growing the Btree.
 263  */
 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
 286 /*
 287  * Utility routines.
 288  */
 289 xfs_dahash_t    xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
 290 int     xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
 291                                    struct xfs_dabuf *leaf2_bp);
 292 int     xfs_attr_leaf_newentsize(struct xfs_da_args *args, int blocksize,
 293                                         int *local);
 294 int     xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp);
 295
 296 #endif  /* __XFS_ATTR_LEAF_H__ */