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         /*
  77          * Allow to open fs with temporary superblock (BTRFS_MAGIC_PARTIAL),
  78          * such fs contains very basic tree layout, just able to be opened.
  79          * Such temporary super is used for mkfs or convert.
  80          */
  81         OPEN_CTREE_TEMPORARY_SUPER = (1U << 12),
  82
  83         /*
  84          * Invalidate the free space tree (i.e., clear the FREE_SPACE_TREE_VALID
  85          * compat_ro bit).
  86          */
  87         OPEN_CTREE_INVALIDATE_FST = (1U << 13),
  88 };
  89
  90 /*
  91  * Modes of superblock access
  92  */
  93 enum btrfs_read_sb_flags {
  94         SBREAD_DEFAULT          = 0,
  95         /* Reading superblock during recovery */
  96         SBREAD_RECOVER          = (1 << 0),
  97
  98         /*
  99          * Read superblock with the fake signature, cannot be used with
 100          * SBREAD_RECOVER
 101          */
 102         SBREAD_TEMPORARY = (1 << 1),
 103
 104         /*
 105          * Equivalent of OPEN_CTREE_IGNORE_FSID_MISMATCH, allow to read
 106          * superblock that has mismatched sb::fsid and sb::dev_item.fsid
 107          */
 108         SBREAD_IGNORE_FSID_MISMATCH = (1 << 2),
 109 };
 110
 111 /*
 112  * Use macro to define mirror super block position,
 113  * so we can use it in static array initialization
 114  */
 115 #define BTRFS_SB_MIRROR_OFFSET(mirror)  ((u64)(SZ_16K) << \
 116                 (BTRFS_SUPER_MIRROR_SHIFT * (mirror)))
 117
 118 static inline u64 btrfs_sb_offset(int mirror)
 119 {
 120         if (mirror)
 121                 return BTRFS_SB_MIRROR_OFFSET(mirror);
 122         return BTRFS_SUPER_INFO_OFFSET;
 123 }
 124
 125 struct btrfs_device;
 126
 127 int read_whole_eb(struct btrfs_fs_info *info, struct extent_buffer *eb, int mirror);
 128 struct extent_buffer* read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
 129                 u64 parent_transid);
 130
 131 int read_extent_data(struct btrfs_fs_info *fs_info, char *data, u64 logical,
 132                      u64 *len, int mirror);
 133 void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
 134                           u64 parent_transid);
 135 struct extent_buffer* btrfs_find_create_tree_block(
 136                 struct btrfs_fs_info *fs_info, u64 bytenr);
 137
 138 void btrfs_setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 139                       u64 objectid);
 140 int clean_tree_block(struct extent_buffer *buf);
 141
 142 void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
 143 struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr);
 144 int btrfs_check_fs_compatibility(struct btrfs_super_block *sb,
 145                                  unsigned int flags);
 146 int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 147                           unsigned flags);
 148 void btrfs_release_all_roots(struct btrfs_fs_info *fs_info);
 149 void btrfs_cleanup_all_caches(struct btrfs_fs_info *fs_info);
 150 int btrfs_scan_fs_devices(int fd, const char *path,
 151                           struct btrfs_fs_devices **fs_devices, u64 sb_bytenr,
 152                           unsigned sbflags, int skip_devices);
 153 int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info,
 154                           u64 chunk_root_bytenr);
 155
 156 struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr,
 157                               unsigned flags);
 158 struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 159                                  unsigned flags);
 160 struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
 161                                          u64 sb_bytenr, u64 root_tree_bytenr,
 162                                          u64 chunk_root_bytenr,
 163                                          unsigned flags);
 164 int close_ctree_fs_info(struct btrfs_fs_info *fs_info);
 165 static inline int close_ctree(struct btrfs_root *root)
 166 {
 167         if (!root)
 168                 return 0;
 169         return close_ctree_fs_info(root->fs_info);
 170 }
 171
 172 int write_all_supers(struct btrfs_fs_info *fs_info);
 173 int write_ctree_super(struct btrfs_trans_handle *trans);
 174 int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
 175                 unsigned sbflags);
 176 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct extent_buffer *bh,
 177                             u64 logical);
 178 struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
 179                                             u64 bytenr, u32 blocksize);
 180 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 181                                       struct btrfs_key *location);
 182 struct btrfs_root *btrfs_read_fs_root_no_cache(struct btrfs_fs_info *fs_info,
 183                                                struct btrfs_key *location);
 184 int btrfs_free_fs_root(struct btrfs_root *root);
 185 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 186 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid);
 187 int btrfs_set_buffer_uptodate(struct extent_buffer *buf);
 188 u32 btrfs_csum_data(char *data, u32 seed, size_t len);
 189 void btrfs_csum_final(u32 crc, u8 *result);
 190
 191 int btrfs_open_device(struct btrfs_device *dev);
 192 int csum_tree_block_size(struct extent_buffer *buf, u16 csum_sectorsize,
 193                          int verify);
 194 int verify_tree_block_csum_silent(struct extent_buffer *buf, u16 csum_size);
 195 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);
 196 int write_tree_block(struct btrfs_trans_handle *trans,
 197                      struct btrfs_fs_info *fs_info,
 198                      struct extent_buffer *eb);
 199 int write_and_map_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb);
 200
 201 #endif