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
  25 #define BTRFS_SUPER_INFO_OFFSET (64 * 1024)
  26 #define BTRFS_SUPER_INFO_SIZE 4096
  27
  28 #define BTRFS_SUPER_MIRROR_MAX   3
  29 #define BTRFS_SUPER_MIRROR_SHIFT 12
  30
  31 enum btrfs_open_ctree_flags {
  32         /* Open filesystem for writes */
  33         OPEN_CTREE_WRITES               = (1U << 0),
  34         /* Allow to open filesystem with some broken tree roots (eg log root) */
  35         OPEN_CTREE_PARTIAL              = (1U << 1),
  36         /* If primary root pinters are invalid, try backup copies */
  37         OPEN_CTREE_BACKUP_ROOT          = (1U << 2),
  38         /* Allow reading all superblock sopies if the primary is damaged */
  39         OPEN_CTREE_RECOVER_SUPER        = (1U << 3),
  40         /* Restoring filesystem image */
  41         OPEN_CTREE_RESTORE              = (1U << 4),
  42         /* Do not read block groups (extent tree) */
  43         OPEN_CTREE_NO_BLOCK_GROUPS      = (1U << 5),
  44         /* Open all devices in O_EXCL mode */
  45         OPEN_CTREE_EXCLUSIVE            = (1U << 6),
  46         /* Do not scan devices */
  47         OPEN_CTREE_NO_DEVICES           = (1U << 7),
  48         /*
  49          * Don't print error messages if bytenr or checksums do not match in
  50          * tree block headers. Turn on by OPEN_CTREE_SUPPRESS_ERROR
  51          */
  52         OPEN_CTREE_SUPPRESS_CHECK_BLOCK_ERRORS  = (1U << 8),
  53         /* Return the chunk root */
  54         __OPEN_CTREE_RETURN_CHUNK_ROOT  = (1U << 9),
  55         OPEN_CTREE_CHUNK_ROOT_ONLY      = OPEN_CTREE_PARTIAL +
  56                                           OPEN_CTREE_SUPPRESS_CHECK_BLOCK_ERRORS +
  57                                           __OPEN_CTREE_RETURN_CHUNK_ROOT,
  58         /*
  59          * TODO: cleanup: Split the open_ctree_flags into more independent
  60          * Tree bits.
  61          * Like split PARTIAL into SKIP_CSUM/SKIP_EXTENT
  62          */
  63
  64         /* Ignore UUID mismatches */
  65         OPEN_CTREE_IGNORE_FSID_MISMATCH = (1U << 10),
  66
  67         /*
  68          * Allow open_ctree_fs_info() to return an incomplete fs_info with
  69          * system chunks from super block only.
  70          * It's useful when chunks are corrupted.
  71          * Makes no sense for open_ctree variants returning btrfs_root.
  72          */
  73         OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR = (1U << 11),
  74
  75         /* Allow to open a partially created filesystem */
  76         OPEN_CTREE_FS_PARTIAL = (1U << 12),
  77 };
  78
  79 /*
  80  * Modes of superblock access
  81  */
  82 enum btrfs_read_sb_flags {
  83         SBREAD_DEFAULT          = 0,
  84         /* Reading superblock during recovery */
  85         SBREAD_RECOVER          = (1 << 0),
  86
  87         /*
  88          * Read superblock with the fake signature, cannot be used with
  89          * SBREAD_RECOVER
  90          */
  91         SBREAD_PARTIAL          = (1 << 1),
  92 };
  93
  94 static inline u64 btrfs_sb_offset(int mirror)
  95 {
  96         u64 start = 16 * 1024;
  97         if (mirror)
  98                 return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror);
  99         return BTRFS_SUPER_INFO_OFFSET;
 100 }
 101
 102 struct btrfs_device;
 103
 104 int read_whole_eb(struct btrfs_fs_info *info, struct extent_buffer *eb, int mirror);
 105 struct extent_buffer* read_tree_block_fs_info(
 106                 struct btrfs_fs_info *fs_info, u64 bytenr, u32 blocksize,
 107                 u64 parent_transid);
 108 static inline struct extent_buffer* read_tree_block(
 109                 struct btrfs_root *root, u64 bytenr, u32 blocksize,
 110                 u64 parent_transid)
 111 {
 112         return read_tree_block_fs_info(root->fs_info, bytenr, blocksize,
 113                         parent_transid);
 114 }
 115
 116 int read_extent_data(struct btrfs_root *root, char *data, u64 logical,
 117                      u64 *len, int mirror);
 118 void readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 119                           u64 parent_transid);
 120 struct extent_buffer* btrfs_find_create_tree_block(
 121                 struct btrfs_fs_info *fs_info, u64 bytenr, u32 blocksize);
 122
 123 void btrfs_setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 124                         u32 stripesize, struct btrfs_root *root,
 125                         struct btrfs_fs_info *fs_info, u64 objectid);
 126 int clean_tree_block(struct btrfs_trans_handle *trans,
 127                      struct btrfs_root *root, struct extent_buffer *buf);
 128
 129 void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
 130 struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr);
 131 int btrfs_check_fs_compatibility(struct btrfs_super_block *sb, int writable);
 132 int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 133                           unsigned flags);
 134 void btrfs_release_all_roots(struct btrfs_fs_info *fs_info);
 135 void btrfs_cleanup_all_caches(struct btrfs_fs_info *fs_info);
 136 int btrfs_scan_fs_devices(int fd, const char *path,
 137                           struct btrfs_fs_devices **fs_devices, u64 sb_bytenr,
 138                           unsigned sbflags, int skip_devices);
 139 int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info,
 140                           u64 chunk_root_bytenr);
 141
 142 struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr,
 143                               unsigned flags);
 144 struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 145                                  unsigned flags);
 146 struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
 147                                          u64 sb_bytenr, u64 root_tree_bytenr,
 148                                          u64 chunk_root_bytenr,
 149                                          unsigned flags);
 150 int close_ctree_fs_info(struct btrfs_fs_info *fs_info);
 151 static inline int close_ctree(struct btrfs_root *root)
 152 {
 153         if (!root)
 154                 return 0;
 155         return close_ctree_fs_info(root->fs_info);
 156 }
 157
 158 int write_all_supers(struct btrfs_root *root);
 159 int write_ctree_super(struct btrfs_trans_handle *trans,
 160                       struct btrfs_root *root);
 161 int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
 162                 unsigned sbflags);
 163 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct extent_buffer *bh,
 164                             u64 logical);
 165 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 166                                             u64 bytenr, u32 blocksize);
 167 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 168                                       struct btrfs_key *location);
 169 struct btrfs_root *btrfs_read_fs_root_no_cache(struct btrfs_fs_info *fs_info,
 170                                                struct btrfs_key *location);
 171 int btrfs_free_fs_root(struct btrfs_root *root);
 172 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 173 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid);
 174 int btrfs_set_buffer_uptodate(struct extent_buffer *buf);
 175 int wait_on_tree_block_writeback(struct btrfs_root *root,
 176                                  struct extent_buffer *buf);
 177 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len);
 178 void btrfs_csum_final(u32 crc, u8 *result);
 179
 180 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 181                              struct btrfs_root *root);
 182 int btrfs_open_device(struct btrfs_device *dev);
 183 int csum_tree_block_size(struct extent_buffer *buf, u16 csum_sectorsize,
 184                          int verify);
 185 int verify_tree_block_csum_silent(struct extent_buffer *buf, u16 csum_size);
 186 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);
 187 int write_tree_block(struct btrfs_trans_handle *trans,
 188                      struct btrfs_root *root,
 189                      struct extent_buffer *eb);
 190 int write_and_map_eb(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 191                      struct extent_buffer *eb);
 192
 193 /* raid6.c */
 194 void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
 195
 196 #endif