LXR linux/fs/xfs/libxfs/xfs_inode

   1/*
   2 * Copyright (c) 2000-2003,2005 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_INODE_FORK_H__
  19#define __XFS_INODE_FORK_H__
  20
  21struct xfs_inode_log_item;
  22struct xfs_dinode;
  23
  24/*
  25 * The following xfs_ext_irec_t struct introduces a second (top) level
  26 * to the in-core extent allocation scheme. These structs are allocated
  27 * in a contiguous block, creating an indirection array where each entry
  28 * (irec) contains a pointer to a buffer of in-core extent records which
  29 * it manages. Each extent buffer is 4k in size, since 4k is the system
  30 * page size on Linux i386 and systems with larger page sizes don't seem
  31 * to gain much, if anything, by using their native page size as the
  32 * extent buffer size. Also, using 4k extent buffers everywhere provides
  33 * a consistent interface for CXFS across different platforms.
  34 *
  35 * There is currently no limit on the number of irec's (extent lists)
  36 * allowed, so heavily fragmented files may require an indirection array
  37 * which spans multiple system pages of memory. The number of extents
  38 * which would require this amount of contiguous memory is very large
  39 * and should not cause problems in the foreseeable future. However,
  40 * if the memory needed for the contiguous array ever becomes a problem,
  41 * it is possible that a third level of indirection may be required.
  42 */
  43typedef struct xfs_ext_irec {
  44        xfs_bmbt_rec_host_t *er_extbuf; /* block of extent records */
  45        xfs_extnum_t    er_extoff;      /* extent offset in file */
  46        xfs_extnum_t    er_extcount;    /* number of extents in page/block */
  47} xfs_ext_irec_t;
  48
  49/*
  50 * File incore extent information, present for each of data & attr forks.
  51 */
  52#define XFS_IEXT_BUFSZ          4096
  53#define XFS_LINEAR_EXTS         (XFS_IEXT_BUFSZ / (uint)sizeof(xfs_bmbt_rec_t))
  54#define XFS_INLINE_EXTS         2
  55#define XFS_INLINE_DATA         32
  56typedef struct xfs_ifork {
  57        int                     if_bytes;       /* bytes in if_u1 */
  58        int                     if_real_bytes;  /* bytes allocated in if_u1 */
  59        struct xfs_btree_block  *if_broot;      /* file's incore btree root */
  60        short                   if_broot_bytes; /* bytes allocated for root */
  61        unsigned char           if_flags;       /* per-fork flags */
  62        union {
  63                xfs_bmbt_rec_host_t *if_extents;/* linear map file exts */
  64                xfs_ext_irec_t  *if_ext_irec;   /* irec map file exts */
  65                char            *if_data;       /* inline file data */
  66        } if_u1;
  67        union {
  68                xfs_bmbt_rec_host_t if_inline_ext[XFS_INLINE_EXTS];
  69                                                /* very small file extents */
  70                char            if_inline_data[XFS_INLINE_DATA];
  71                                                /* very small file data */
  72                xfs_dev_t       if_rdev;        /* dev number if special */
  73                uuid_t          if_uuid;        /* mount point value */
  74        } if_u2;
  75} xfs_ifork_t;
  76
  77/*
  78 * Per-fork incore inode flags.
  79 */
  80#define XFS_IFINLINE    0x01    /* Inline data is read in */
  81#define XFS_IFEXTENTS   0x02    /* All extent pointers are read in */
  82#define XFS_IFBROOT     0x04    /* i_broot points to the bmap b-tree root */
  83#define XFS_IFEXTIREC   0x08    /* Indirection array of extent blocks */
  84
  85/*
  86 * Fork handling.
  87 */
  88
  89#define XFS_IFORK_Q(ip)                 ((ip)->i_d.di_forkoff != 0)
  90#define XFS_IFORK_BOFF(ip)              ((int)((ip)->i_d.di_forkoff << 3))
  91
  92#define XFS_IFORK_PTR(ip,w)             \
  93        ((w) == XFS_DATA_FORK ? \
  94                &(ip)->i_df : \
  95                (ip)->i_afp)
  96#define XFS_IFORK_DSIZE(ip) \
  97        (XFS_IFORK_Q(ip) ? \
  98                XFS_IFORK_BOFF(ip) : \
  99                XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version))
 100#define XFS_IFORK_ASIZE(ip) \
 101        (XFS_IFORK_Q(ip) ? \
 102                XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version) - \
 103                        XFS_IFORK_BOFF(ip) : \
 104                0)
 105#define XFS_IFORK_SIZE(ip,w) \
 106        ((w) == XFS_DATA_FORK ? \
 107                XFS_IFORK_DSIZE(ip) : \
 108                XFS_IFORK_ASIZE(ip))
 109#define XFS_IFORK_FORMAT(ip,w) \
 110        ((w) == XFS_DATA_FORK ? \
 111                (ip)->i_d.di_format : \
 112                (ip)->i_d.di_aformat)
 113#define XFS_IFORK_FMT_SET(ip,w,n) \
 114        ((w) == XFS_DATA_FORK ? \
 115                ((ip)->i_d.di_format = (n)) : \
 116                ((ip)->i_d.di_aformat = (n)))
 117#define XFS_IFORK_NEXTENTS(ip,w) \
 118        ((w) == XFS_DATA_FORK ? \
 119                (ip)->i_d.di_nextents : \
 120                (ip)->i_d.di_anextents)
 121#define XFS_IFORK_NEXT_SET(ip,w,n) \
 122        ((w) == XFS_DATA_FORK ? \
 123                ((ip)->i_d.di_nextents = (n)) : \
 124                ((ip)->i_d.di_anextents = (n)))
 125#define XFS_IFORK_MAXEXT(ip, w) \
 126        (XFS_IFORK_SIZE(ip, w) / sizeof(xfs_bmbt_rec_t))
 127
 128int             xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *);
 129void            xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
 130                                struct xfs_inode_log_item *, int);
 131void            xfs_idestroy_fork(struct xfs_inode *, int);
 132void            xfs_idata_realloc(struct xfs_inode *, int, int);
 133void            xfs_iroot_realloc(struct xfs_inode *, int, int);
 134int             xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
 135int             xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
 136                                  int);
 137
 138struct xfs_bmbt_rec_host *
 139                xfs_iext_get_ext(struct xfs_ifork *, xfs_extnum_t);
 140void            xfs_iext_insert(struct xfs_inode *, xfs_extnum_t, xfs_extnum_t,
 141                                struct xfs_bmbt_irec *, int);
 142void            xfs_iext_add(struct xfs_ifork *, xfs_extnum_t, int);
 143void            xfs_iext_add_indirect_multi(struct xfs_ifork *, int,
 144                                            xfs_extnum_t, int);
 145void            xfs_iext_remove(struct xfs_inode *, xfs_extnum_t, int, int);
 146void            xfs_iext_remove_inline(struct xfs_ifork *, xfs_extnum_t, int);
 147void            xfs_iext_remove_direct(struct xfs_ifork *, xfs_extnum_t, int);
 148void            xfs_iext_remove_indirect(struct xfs_ifork *, xfs_extnum_t, int);
 149void            xfs_iext_realloc_direct(struct xfs_ifork *, int);
 150void            xfs_iext_direct_to_inline(struct xfs_ifork *, xfs_extnum_t);
 151void            xfs_iext_inline_to_direct(struct xfs_ifork *, int);
 152void            xfs_iext_destroy(struct xfs_ifork *);
 153struct xfs_bmbt_rec_host *
 154                xfs_iext_bno_to_ext(struct xfs_ifork *, xfs_fileoff_t, int *);
 155struct xfs_ext_irec *
 156                xfs_iext_bno_to_irec(struct xfs_ifork *, xfs_fileoff_t, int *);
 157struct xfs_ext_irec *
 158                xfs_iext_idx_to_irec(struct xfs_ifork *, xfs_extnum_t *, int *,
 159                                     int);
 160void            xfs_iext_irec_init(struct xfs_ifork *);
 161struct xfs_ext_irec *
 162                xfs_iext_irec_new(struct xfs_ifork *, int);
 163void            xfs_iext_irec_remove(struct xfs_ifork *, int);
 164void            xfs_iext_irec_compact(struct xfs_ifork *);
 165void            xfs_iext_irec_compact_pages(struct xfs_ifork *);
 166void            xfs_iext_irec_compact_full(struct xfs_ifork *);
 167void            xfs_iext_irec_update_extoffs(struct xfs_ifork *, int, int);
 168
 169extern struct kmem_zone *xfs_ifork_zone;
 170
 171#endif  /* __XFS_INODE_FORK_H__ */
 172