fs/xfs/xfs_attr_leaf.h

   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 modify it
   6  * under the terms of version 2 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, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12  *
  13  * Further, this software is distributed without any warranty that it is
  14  * free of the rightful claim of any third person regarding infringement
  15  * or the like.  Any license provided herein, whether implied or
  16  * otherwise, applies only to this software file.  Patent licenses, if
  17  * any, provided herein do not apply to combinations of this program with
  18  * other software, or any other product whatsoever.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write the Free Software Foundation, Inc., 59
  22  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  23  *
  24  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  25  * Mountain View, CA  94043, or:
  26  *
  27  * http://www.sgi.com
  28  *
  29  * For further information regarding this notice, see:
  30  *
  31  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  32  */
  33 #ifndef __XFS_ATTR_LEAF_H__
  34 #define __XFS_ATTR_LEAF_H__
  35
  36 /*
  37  * Attribute storage layout, internal structure, access macros, etc.
  38  *
  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.
  44  */
  45
  46 struct attrlist;
  47 struct attrlist_cursor_kern;
  48 struct attrnames;
  49 struct xfs_dabuf;
  50 struct xfs_da_args;
  51 struct xfs_da_state;
  52 struct xfs_da_state_blk;
  53 struct xfs_inode;
  54 struct xfs_trans;
  55
  56 /*========================================================================
  57  * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
  58  *========================================================================*/
  59
  60 /*
  61  * This is the structure of the leaf nodes in the Btree.
  62  *
  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.
  70  *
  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.
  76  *
  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.
  80  *
  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.
  87  */
  88 #define XFS_ATTR_LEAF_MAPSIZE   3       /* how many freespace slots */
  89
  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 */
  97                 __uint8_t  pad1;
  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 */
 102         } hdr;
 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;
 126
 127 /*
 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.
 131  */
 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)
 140
 141 /*
 142  * Alignment for namelist and valuelist entries (since they are mixed
 143  * there can be only one alignment value)
 144  */
 145 #define XFS_ATTR_LEAF_NAME_ALIGN        ((uint)sizeof(xfs_dablk_t))
 146
 147 /*
 148  * Cast typed pointers for "local" and "remote" name/value structs.
 149  */
 150 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_REMOTE)
 151 xfs_attr_leaf_name_remote_t *
 152 xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx);
 153 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    \
 154         xfs_attr_leaf_name_remote(leafp,idx)
 155 #else
 156 #define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)    /* remote name struct ptr */ \
 157         ((xfs_attr_leaf_name_remote_t *)                \
 158          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 159 #endif
 160 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_LOCAL)
 161 xfs_attr_leaf_name_local_t *
 162 xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx);
 163 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     \
 164         xfs_attr_leaf_name_local(leafp,idx)
 165 #else
 166 #define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)     /* local name struct ptr */ \
 167         ((xfs_attr_leaf_name_local_t *)         \
 168          &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 169 #endif
 170 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME)
 171 char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx);
 172 #define XFS_ATTR_LEAF_NAME(leafp,idx)           xfs_attr_leaf_name(leafp,idx)
 173 #else
 174 #define XFS_ATTR_LEAF_NAME(leafp,idx)           /* generic name struct ptr */ \
 175         (&((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
 176 #endif
 177
 178 /*
 179  * Calculate total bytes used (including trailing pad for alignment) for
 180  * a "local" name/value structure, a "remote" name/value structure, and
 181  * a pointer which might be either.
 182  */
 183 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_REMOTE)
 184 int xfs_attr_leaf_entsize_remote(int nlen);
 185 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      \
 186         xfs_attr_leaf_entsize_remote(nlen)
 187 #else
 188 #define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)      /* space for remote struct */ \
 189         (((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
 190           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 191 #endif
 192 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL)
 193 int xfs_attr_leaf_entsize_local(int nlen, int vlen);
 194 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  \
 195         xfs_attr_leaf_entsize_local(nlen,vlen)
 196 #else
 197 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)  /* space for local struct */ \
 198         (((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + \
 199           XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
 200 #endif
 201 #if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX)
 202 int xfs_attr_leaf_entsize_local_max(int bsize);
 203 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  \
 204         xfs_attr_leaf_entsize_local_max(bsize)
 205 #else
 206 #define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)  /* max local struct size */ \
 207         (((bsize) >> 1) + ((bsize) >> 2))
 208 #endif
 209
 210
 211 /*========================================================================
 212  * Structure used to pass context around among the routines.
 213  *========================================================================*/
 214
 215 typedef struct xfs_attr_list_context {
 216         struct xfs_inode                *dp;    /* inode */
 217         struct attrlist_cursor_kern     *cursor;/* position in list */
 218         struct attrlist                 *alist; /* output buffer */
 219         int                             count;  /* num used entries */
 220         int                             dupcnt; /* count dup hashvals seen */
 221         int                             bufsize;/* total buffer size */
 222         int                             firstu; /* first used byte in buffer */
 223         int                             flags;  /* from VOP call */
 224         int                             resynch;/* T/F: resynch with cursor */
 225 } xfs_attr_list_context_t;
 226
 227 /*
 228  * Used to keep a list of "remote value" extents when unlinking an inode.
 229  */
 230 typedef struct xfs_attr_inactive_list {
 231         xfs_dablk_t     valueblk;       /* block number of value bytes */
 232         int             valuelen;       /* number of bytes in value */
 233 } xfs_attr_inactive_list_t;
 234
 235
 236 /*========================================================================
 237  * Function prototypes for the kernel.
 238  *========================================================================*/
 239
 240 /*
 241  * Internal routines when attribute fork size < XFS_LITINO(mp).
 242  */
 243 void    xfs_attr_shortform_create(struct xfs_da_args *args);
 244 void    xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff);
 245 int     xfs_attr_shortform_lookup(struct xfs_da_args *args);
 246 int     xfs_attr_shortform_getvalue(struct xfs_da_args *args);
 247 int     xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
 248 int     xfs_attr_shortform_remove(struct xfs_da_args *args);
 249 int     xfs_attr_shortform_list(struct xfs_attr_list_context *context);
 250 int     xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
 251 int     xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes);
 252
 253
 254 /*
 255  * Internal routines when attribute fork size == XFS_LBSIZE(mp).
 256  */
 257 int     xfs_attr_leaf_to_node(struct xfs_da_args *args);
 258 int     xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
 259                                    struct xfs_da_args *args, int forkoff);
 260 int     xfs_attr_leaf_clearflag(struct xfs_da_args *args);
 261 int     xfs_attr_leaf_setflag(struct xfs_da_args *args);
 262 int     xfs_attr_leaf_flipflags(xfs_da_args_t *args);
 263
 264 /*
 265  * Routines used for growing the Btree.
 266  */
 267 int     xfs_attr_leaf_split(struct xfs_da_state *state,
 268                                    struct xfs_da_state_blk *oldblk,
 269                                    struct xfs_da_state_blk *newblk);
 270 int     xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf,
 271                                         struct xfs_da_args *args);
 272 int     xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args);
 273 int     xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer,
 274                                  struct xfs_da_args *args);
 275 int     xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer,
 276                                     struct xfs_da_args *args);
 277 int     xfs_attr_leaf_list_int(struct xfs_dabuf *bp,
 278                                       struct xfs_attr_list_context *context);
 279
 280 /*
 281  * Routines used for shrinking the Btree.
 282  */
 283 int     xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval);
 284 void    xfs_attr_leaf_unbalance(struct xfs_da_state *state,
 285                                        struct xfs_da_state_blk *drop_blk,
 286                                        struct xfs_da_state_blk *save_blk);
 287 int     xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp);
 288
 289 /*
 290  * Utility routines.
 291  */
 292 xfs_dahash_t    xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
 293 int     xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
 294                                    struct xfs_dabuf *leaf2_bp);
 295 int     xfs_attr_leaf_newentsize(int namelen, int valuelen, int blocksize,
 296                                         int *local);
 297 int     xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp);
 298
 299 #endif  /* __XFS_ATTR_LEAF_H__ */