disk-io.h

   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 #ifndef __BTRFS_DISK_IO_H__
  20 #define __BTRFS_DISK_IO_H__
  21
  22 #include "kerncompat.h"
  23 #include "ctree.h"
  24 #include "sizes.h"
  25
  26 #define BTRFS_SUPER_INFO_OFFSET SZ_64K
  27 #define BTRFS_SUPER_INFO_SIZE 4096
  28
  29 #define BTRFS_SUPER_MIRROR_MAX   3
  30 #define BTRFS_SUPER_MIRROR_SHIFT 12
  31
  32 enum btrfs_open_ctree_flags {
  33         /* Open filesystem for writes */
  34         OPEN_CTREE_WRITES               = (1U << 0),
  35         /* Allow to open filesystem with some broken tree roots (eg log root) */
  36         OPEN_CTREE_PARTIAL              = (1U << 1),
  37         /* If primary root pinters are invalid, try backup copies */
  38         OPEN_CTREE_BACKUP_ROOT          = (1U << 2),
  39         /* Allow reading all superblock sopies if the primary is damaged */
  40         OPEN_CTREE_RECOVER_SUPER        = (1U << 3),
  41         /* Restoring filesystem image */
  42         OPEN_CTREE_RESTORE              = (1U << 4),
  43         /* Do not read block groups (extent tree) */
  44         OPEN_CTREE_NO_BLOCK_GROUPS      = (1U << 5),
  45         /* Open all devices in O_EXCL mode */
  46         OPEN_CTREE_EXCLUSIVE            = (1U << 6),
  47         /* Do not scan devices */
  48         OPEN_CTREE_NO_DEVICES           = (1U << 7),
  49         /*
  50          * Don't print error messages if bytenr or checksums do not match in
  51          * tree block headers. Turn on by OPEN_CTREE_SUPPRESS_ERROR
  52          */
  53         OPEN_CTREE_SUPPRESS_CHECK_BLOCK_ERRORS  = (1U << 8),
  54         /* Return the chunk root */
  55         __OPEN_CTREE_RETURN_CHUNK_ROOT  = (1U << 9),
  56         OPEN_CTREE_CHUNK_ROOT_ONLY      = OPEN_CTREE_PARTIAL +
  57                                           OPEN_CTREE_SUPPRESS_CHECK_BLOCK_ERRORS +
  58                                           __OPEN_CTREE_RETURN_CHUNK_ROOT,
  59         /*
  60          * TODO: cleanup: Split the open_ctree_flags into more independent
  61          * Tree bits.
  62          * Like split PARTIAL into SKIP_CSUM/SKIP_EXTENT
  63          */
  64
  65         /* Ignore UUID mismatches */
  66         OPEN_CTREE_IGNORE_FSID_MISMATCH = (1U << 10),
  67
  68         /*
  69          * Allow open_ctree_fs_info() to return an incomplete fs_info with
  70          * system chunks from super block only.
  71          * It's useful when chunks are corrupted.
  72          * Makes no sense for open_ctree variants returning btrfs_root.
  73          */
  74         OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR = (1U << 11),
  75
  76         /* Allow to open a partially created filesystem */
  77         OPEN_CTREE_FS_PARTIAL = (1U << 12),
  78
  79         /*
  80          * Invalidate the free space tree (i.e., clear the FREE_SPACE_TREE_VALID
  81          * compat_ro bit).
  82          */
  83         OPEN_CTREE_INVALIDATE_FST = (1U << 13),
  84 };
  85
  86 /*
  87  * Modes of superblock access
  88  */
  89 enum btrfs_read_sb_flags {
  90         SBREAD_DEFAULT          = 0,
  91         /* Reading superblock during recovery */
  92         SBREAD_RECOVER          = (1 << 0),
  93
  94         /*
  95          * Read superblock with the fake signature, cannot be used with
  96          * SBREAD_RECOVER
  97          */
  98         SBREAD_PARTIAL          = (1 << 1),
  99 };
 100
 101 /*
 102  * Use macro to define mirror super block position,
 103  * so we can use it in static array initialization
 104  */
 105 #define BTRFS_SB_MIRROR_OFFSET(mirror)  ((u64)(SZ_16K) << \
 106                 (BTRFS_SUPER_MIRROR_SHIFT * (mirror)))
 107
 108 static inline u64 btrfs_sb_offset(int mirror)
 109 {
 110         if (mirror)
 111                 return BTRFS_SB_MIRROR_OFFSET(mirror);
 112         return BTRFS_SUPER_INFO_OFFSET;
 113 }
 114
 115 struct btrfs_device;
 116
 117 int read_whole_eb(struct btrfs_fs_info *info, struct extent_buffer *eb, int mirror);
 118 struct extent_buffer* read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
 119                 u64 parent_transid);
 120
 121 int read_extent_data(struct btrfs_fs_info *fs_info, char *data, u64 logical,
 122                      u64 *len, int mirror);
 123 void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
 124                           u64 parent_transid);
 125 struct extent_buffer* btrfs_find_create_tree_block(
 126                 struct btrfs_fs_info *fs_info, u64 bytenr);
 127
 128 void btrfs_setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 129                       u64 objectid);
 130 int clean_tree_block(struct btrfs_trans_handle *trans,
 131                      struct btrfs_root *root, struct extent_buffer *buf);
 132
 133 void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
 134 struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr);
 135 int btrfs_check_fs_compatibility(struct btrfs_super_block *sb,
 136                                  unsigned int flags);
 137 int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 138                           unsigned flags);
 139 void btrfs_release_all_roots(struct btrfs_fs_info *fs_info);
 140 void btrfs_cleanup_all_caches(struct btrfs_fs_info *fs_info);
 141 int btrfs_scan_fs_devices(int fd, const char *path,
 142                           struct btrfs_fs_devices **fs_devices, u64 sb_bytenr,
 143                           unsigned sbflags, int skip_devices);
 144 int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info,
 145                           u64 chunk_root_bytenr);
 146
 147 struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr,
 148                               unsigned flags);
 149 struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 150                                  unsigned flags);
 151 struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
 152                                          u64 sb_bytenr, u64 root_tree_bytenr,
 153                                          u64 chunk_root_bytenr,
 154                                          unsigned flags);
 155 int close_ctree_fs_info(struct btrfs_fs_info *fs_info);
 156 static inline int close_ctree(struct btrfs_root *root)
 157 {
 158         if (!root)
 159                 return 0;
 160         return close_ctree_fs_info(root->fs_info);
 161 }
 162
 163 int write_all_supers(struct btrfs_fs_info *fs_info);
 164 int write_ctree_super(struct btrfs_trans_handle *trans,
 165                       struct btrfs_fs_info *fs_info);
 166 int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
 167                 unsigned sbflags);
 168 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct extent_buffer *bh,
 169                             u64 logical);
 170 struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
 171                                             u64 bytenr, u32 blocksize);
 172 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 173                                       struct btrfs_key *location);
 174 struct btrfs_root *btrfs_read_fs_root_no_cache(struct btrfs_fs_info *fs_info,
 175                                                struct btrfs_key *location);
 176 int btrfs_free_fs_root(struct btrfs_root *root);
 177 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 178 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid);
 179 int btrfs_set_buffer_uptodate(struct extent_buffer *buf);
 180 u32 btrfs_csum_data(char *data, u32 seed, size_t len);
 181 void btrfs_csum_final(u32 crc, u8 *result);
 182
 183 int btrfs_open_device(struct btrfs_device *dev);
 184 int csum_tree_block_size(struct extent_buffer *buf, u16 csum_sectorsize,
 185                          int verify);
 186 int verify_tree_block_csum_silent(struct extent_buffer *buf, u16 csum_size);
 187 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);
 188 int write_tree_block(struct btrfs_trans_handle *trans,
 189                      struct btrfs_fs_info *fs_info,
 190                      struct extent_buffer *eb);
 191 int write_and_map_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb);
 192
 193 #endif