Chris Mason | 0f82731 | 2007-10-15 16:18:56 -0400 | [diff] [blame] | 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> |
Chris Mason | d352ac6 | 2008-09-29 15:18:18 -0400 | [diff] [blame] | 20 | |
| 21 | /* this is some deeply nasty code. ctree.h has a different |
| 22 | * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef |
| 23 | * |
| 24 | * The end result is that anyone who #includes ctree.h gets a |
| 25 | * declaration for the btrfs_set_foo functions and btrfs_foo functions |
| 26 | * |
| 27 | * This file declares the macros and then #includes ctree.h, which results |
| 28 | * in cpp creating the function here based on the template below. |
| 29 | * |
| 30 | * These setget functions do all the extent_buffer related mapping |
| 31 | * required to efficiently read and write specific fields in the extent |
| 32 | * buffers. Every pointer to metadata items in btrfs is really just |
| 33 | * an unsigned long offset into the extent buffer which has been |
| 34 | * cast to a specific type. This gives us all the gcc type checking. |
| 35 | * |
| 36 | * The extent buffer api is used to do all the kmapping and page |
| 37 | * spanning work required to get extent buffers in highmem and have |
| 38 | * a metadata blocksize different from the page size. |
Chris Mason | c99e905c | 2008-12-02 11:18:37 -0500 | [diff] [blame] | 39 | * |
| 40 | * The macro starts with a simple function prototype declaration so that |
| 41 | * sparse won't complain about it being static. |
Chris Mason | d352ac6 | 2008-09-29 15:18:18 -0400 | [diff] [blame] | 42 | */ |
| 43 | |
Chris Mason | 0f82731 | 2007-10-15 16:18:56 -0400 | [diff] [blame] | 44 | #define BTRFS_SETGET_FUNCS(name, type, member, bits) \ |
Chris Mason | c99e905c | 2008-12-02 11:18:37 -0500 | [diff] [blame] | 45 | u##bits btrfs_##name(struct extent_buffer *eb, type *s); \ |
| 46 | void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \ |
Chris Mason | 0f82731 | 2007-10-15 16:18:56 -0400 | [diff] [blame] | 47 | u##bits btrfs_##name(struct extent_buffer *eb, \ |
| 48 | type *s) \ |
| 49 | { \ |
David Miller | df68b8a | 2008-02-15 10:40:52 -0500 | [diff] [blame] | 50 | unsigned long part_offset = (unsigned long)s; \ |
| 51 | unsigned long offset = part_offset + offsetof(type, member); \ |
| 52 | type *p; \ |
Chris Mason | a659171 | 2011-07-19 12:04:14 -0400 | [diff] [blame^] | 53 | int err; \ |
| 54 | char *kaddr; \ |
| 55 | unsigned long map_start; \ |
| 56 | unsigned long map_len; \ |
| 57 | u##bits res; \ |
| 58 | err = map_private_extent_buffer(eb, offset, \ |
| 59 | sizeof(((type *)0)->member), \ |
| 60 | &kaddr, &map_start, &map_len); \ |
| 61 | if (err) { \ |
| 62 | __le##bits leres; \ |
| 63 | read_eb_member(eb, s, type, member, &leres); \ |
| 64 | return le##bits##_to_cpu(leres); \ |
| 65 | } \ |
| 66 | p = (type *)(kaddr + part_offset - map_start); \ |
| 67 | res = le##bits##_to_cpu(p->member); \ |
| 68 | return res; \ |
Chris Mason | 0f82731 | 2007-10-15 16:18:56 -0400 | [diff] [blame] | 69 | } \ |
| 70 | void btrfs_set_##name(struct extent_buffer *eb, \ |
| 71 | type *s, u##bits val) \ |
| 72 | { \ |
David Miller | df68b8a | 2008-02-15 10:40:52 -0500 | [diff] [blame] | 73 | unsigned long part_offset = (unsigned long)s; \ |
| 74 | unsigned long offset = part_offset + offsetof(type, member); \ |
| 75 | type *p; \ |
Chris Mason | a659171 | 2011-07-19 12:04:14 -0400 | [diff] [blame^] | 76 | int err; \ |
| 77 | char *kaddr; \ |
| 78 | unsigned long map_start; \ |
| 79 | unsigned long map_len; \ |
| 80 | err = map_private_extent_buffer(eb, offset, \ |
| 81 | sizeof(((type *)0)->member), \ |
| 82 | &kaddr, &map_start, &map_len); \ |
| 83 | if (err) { \ |
| 84 | __le##bits val2; \ |
| 85 | val2 = cpu_to_le##bits(val); \ |
| 86 | write_eb_member(eb, s, type, member, &val2); \ |
| 87 | return; \ |
| 88 | } \ |
| 89 | p = (type *)(kaddr + part_offset - map_start); \ |
| 90 | p->member = cpu_to_le##bits(val); \ |
Chris Mason | 0f82731 | 2007-10-15 16:18:56 -0400 | [diff] [blame] | 91 | } |
| 92 | |
| 93 | #include "ctree.h" |
| 94 | |
Chris Mason | e644d02 | 2007-11-06 15:09:29 -0500 | [diff] [blame] | 95 | void btrfs_node_key(struct extent_buffer *eb, |
| 96 | struct btrfs_disk_key *disk_key, int nr) |
| 97 | { |
| 98 | unsigned long ptr = btrfs_node_key_ptr_offset(nr); |
Chris Mason | e644d02 | 2007-11-06 15:09:29 -0500 | [diff] [blame] | 99 | read_eb_member(eb, (struct btrfs_key_ptr *)ptr, |
| 100 | struct btrfs_key_ptr, key, disk_key); |
| 101 | } |