fs/btrfs/struct-funcs.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/highmem.h>
  20 #define BTRFS_SETGET_FUNCS(name, type, member, bits)                    \
  21 u##bits btrfs_##name(struct extent_buffer *eb,                          \
  22                                    type *s)                             \
  23 {                                                                       \
  24         unsigned long part_offset = (unsigned long)s;                   \
  25         unsigned long offset = part_offset + offsetof(type, member);    \
  26         type *p;                                                        \
  27         /* ugly, but we want the fast path here */                      \
  28         if (eb->map_token && offset >= eb->map_start &&                 \
  29             offset + sizeof(((type *)0)->member) <= eb->map_start +     \
  30             eb->map_len) {                                              \
  31                 p = (type *)(eb->kaddr + part_offset - eb->map_start);  \
  32                 return le##bits##_to_cpu(p->member);                    \
  33         }                                                               \
  34         {                                                               \
  35                 int err;                                                \
  36                 char *map_token;                                        \
  37                 char *kaddr;                                            \
  38                 int unmap_on_exit = (eb->map_token == NULL);            \
  39                 unsigned long map_start;                                \
  40                 unsigned long map_len;                                  \
  41                 __le##bits res;                                         \
  42                 err = map_extent_buffer(eb, offset,                     \
  43                                 sizeof(((type *)0)->member),            \
  44                                 &map_token, &kaddr,                     \
  45                                 &map_start, &map_len, KM_USER1);        \
  46                 if (err) {                                              \
  47                         read_eb_member(eb, s, type, member, &res);      \
  48                         return le##bits##_to_cpu(res);                  \
  49                 }                                                       \
  50                 p = (type *)(kaddr + part_offset - map_start);          \
  51                 res = le##bits##_to_cpu(p->member);                     \
  52                 if (unmap_on_exit)                                      \
  53                         unmap_extent_buffer(eb, map_token, KM_USER1);   \
  54                 return res;                                             \
  55         }                                                               \
  56 }                                                                       \
  57 void btrfs_set_##name(struct extent_buffer *eb,                         \
  58                                     type *s, u##bits val)               \
  59 {                                                                       \
  60         unsigned long part_offset = (unsigned long)s;                   \
  61         unsigned long offset = part_offset + offsetof(type, member);    \
  62         type *p;                                                        \
  63         /* ugly, but we want the fast path here */                      \
  64         if (eb->map_token && offset >= eb->map_start &&                 \
  65             offset + sizeof(((type *)0)->member) <= eb->map_start +     \
  66             eb->map_len) {                                              \
  67                 p = (type *)(eb->kaddr + part_offset - eb->map_start);  \
  68                 p->member = cpu_to_le##bits(val);                       \
  69                 return;                                                 \
  70         }                                                               \
  71         {                                                               \
  72                 int err;                                                \
  73                 char *map_token;                                        \
  74                 char *kaddr;                                            \
  75                 int unmap_on_exit = (eb->map_token == NULL);            \
  76                 unsigned long map_start;                                \
  77                 unsigned long map_len;                                  \
  78                 err = map_extent_buffer(eb, offset,                     \
  79                                 sizeof(((type *)0)->member),            \
  80                                 &map_token, &kaddr,                     \
  81                                 &map_start, &map_len, KM_USER1);        \
  82                 if (err) {                                              \
  83                         val = cpu_to_le##bits(val);                     \
  84                         write_eb_member(eb, s, type, member, &val);     \
  85                         return;                                         \
  86                 }                                                       \
  87                 p = (type *)(kaddr + part_offset - map_start);          \
  88                 p->member = cpu_to_le##bits(val);                       \
  89                 if (unmap_on_exit)                                      \
  90                         unmap_extent_buffer(eb, map_token, KM_USER1);   \
  91         }                                                               \
  92 }
  93
  94 #include "ctree.h"
  95
  96 void btrfs_node_key(struct extent_buffer *eb,
  97                     struct btrfs_disk_key *disk_key, int nr)
  98 {
  99         unsigned long ptr = btrfs_node_key_ptr_offset(nr);
 100         if (eb->map_token && ptr >= eb->map_start &&
 101             ptr + sizeof(*disk_key) <= eb->map_start + eb->map_len) {
 102                 memcpy(disk_key, eb->kaddr + ptr - eb->map_start,
 103                         sizeof(*disk_key));
 104                 return;
 105         } else if (eb->map_token) {
 106                 unmap_extent_buffer(eb, eb->map_token, KM_USER1);
 107                 eb->map_token = NULL;
 108         }
 109         read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
 110                        struct btrfs_key_ptr, key, disk_key);
 111 }