fs/xfs/libxfs/xfs_inode_fork.h

   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
  21 struct xfs_inode_log_item;
  22 struct 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  */
  43 typedef 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
  56 typedef 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
 128 int             xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *);
 129 void            xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
 130                                 struct xfs_inode_log_item *, int);
 131 void            xfs_idestroy_fork(struct xfs_inode *, int);
 132 void            xfs_idata_realloc(struct xfs_inode *, int, int);
 133 void            xfs_iroot_realloc(struct xfs_inode *, int, int);
 134 int             xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
 135 int             xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
 136                                   int);
 137
 138 struct xfs_bmbt_rec_host *
 139                 xfs_iext_get_ext(struct xfs_ifork *, xfs_extnum_t);
 140 void            xfs_iext_insert(struct xfs_inode *, xfs_extnum_t, xfs_extnum_t,
 141                                 struct xfs_bmbt_irec *, int);
 142 void            xfs_iext_add(struct xfs_ifork *, xfs_extnum_t, int);
 143 void            xfs_iext_add_indirect_multi(struct xfs_ifork *, int,
 144                                             xfs_extnum_t, int);
 145 void            xfs_iext_remove(struct xfs_inode *, xfs_extnum_t, int, int);
 146 void            xfs_iext_remove_inline(struct xfs_ifork *, xfs_extnum_t, int);
 147 void            xfs_iext_remove_direct(struct xfs_ifork *, xfs_extnum_t, int);
 148 void            xfs_iext_remove_indirect(struct xfs_ifork *, xfs_extnum_t, int);
 149 void            xfs_iext_realloc_direct(struct xfs_ifork *, int);
 150 void            xfs_iext_direct_to_inline(struct xfs_ifork *, xfs_extnum_t);
 151 void            xfs_iext_inline_to_direct(struct xfs_ifork *, int);
 152 void            xfs_iext_destroy(struct xfs_ifork *);
 153 struct xfs_bmbt_rec_host *
 154                 xfs_iext_bno_to_ext(struct xfs_ifork *, xfs_fileoff_t, int *);
 155 struct xfs_ext_irec *
 156                 xfs_iext_bno_to_irec(struct xfs_ifork *, xfs_fileoff_t, int *);
 157 struct xfs_ext_irec *
 158                 xfs_iext_idx_to_irec(struct xfs_ifork *, xfs_extnum_t *, int *,
 159                                      int);
 160 void            xfs_iext_irec_init(struct xfs_ifork *);
 161 struct xfs_ext_irec *
 162                 xfs_iext_irec_new(struct xfs_ifork *, int);
 163 void            xfs_iext_irec_remove(struct xfs_ifork *, int);
 164 void            xfs_iext_irec_compact(struct xfs_ifork *);
 165 void            xfs_iext_irec_compact_pages(struct xfs_ifork *);
 166 void            xfs_iext_irec_compact_full(struct xfs_ifork *);
 167 void            xfs_iext_irec_update_extoffs(struct xfs_ifork *, int, int);
 168
 169 extern struct kmem_zone *xfs_ifork_zone;
 170
 171 #endif  /* __XFS_INODE_FORK_H__ */