diff options
Diffstat (limited to 'disk-io.c')
| -rw-r--r-- | disk-io.c | 54 |
1 files changed, 44 insertions, 10 deletions
@@ -808,8 +808,27 @@ int btrfs_check_fs_compatibility(struct btrfs_super_block *sb, int writable) return 0; } +static int find_best_backup_root(struct btrfs_super_block *super) +{ + struct btrfs_root_backup *backup; + u64 orig_gen = btrfs_super_generation(super); + u64 gen = 0; + int best_index = 0; + int i; + + for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) { + backup = super->super_roots + i; + if (btrfs_backup_tree_root_gen(backup) != orig_gen && + btrfs_backup_tree_root_gen(backup) > gen) { + best_index = i; + gen = btrfs_backup_tree_root_gen(backup); + } + } + return best_index; +} + int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, - u64 root_tree_bytenr, int partial) + u64 root_tree_bytenr, int partial, int backup_root) { struct btrfs_super_block *sb = fs_info->super_copy; struct btrfs_root *root; @@ -833,8 +852,20 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, blocksize = btrfs_level_size(root, btrfs_super_root_level(sb)); generation = btrfs_super_generation(sb); - if (!root_tree_bytenr) + if (!root_tree_bytenr && !backup_root) { root_tree_bytenr = btrfs_super_root(sb); + } else if (backup_root) { + struct btrfs_root_backup *backup; + int index = find_best_backup_root(sb); + if (index >= BTRFS_NUM_BACKUP_ROOTS) { + fprintf(stderr, "Invalid backup root number\n"); + return -EIO; + } + backup = fs_info->super_copy->super_roots + index; + root_tree_bytenr = btrfs_backup_tree_root(backup); + generation = btrfs_backup_tree_root_gen(backup); + } + root->node = read_tree_block(root, root_tree_bytenr, blocksize, generation); if (!extent_buffer_uptodate(root->node)) { @@ -1005,7 +1036,8 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path, u64 sb_bytenr, u64 root_tree_bytenr, int writes, int partial, int restore, - int recover_super) + int recover_super, + int backup_root) { struct btrfs_fs_info *fs_info; struct btrfs_super_block *disk_super; @@ -1068,7 +1100,8 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path, (unsigned long)btrfs_header_chunk_tree_uuid(eb), BTRFS_UUID_SIZE); - ret = btrfs_setup_all_roots(fs_info, root_tree_bytenr, partial); + ret = btrfs_setup_all_roots(fs_info, root_tree_bytenr, partial, + backup_root); if (ret) goto out_failed; @@ -1105,14 +1138,15 @@ struct btrfs_fs_info *open_ctree_fs_info_restore(const char *filename, return NULL; } info = __open_ctree_fd(fp, filename, sb_bytenr, root_tree_bytenr, - writes, partial, restore, 0); + writes, partial, restore, 0, 0); close(fp); return info; } struct btrfs_fs_info *open_ctree_fs_info(const char *filename, u64 sb_bytenr, u64 root_tree_bytenr, - int writes, int partial) + int writes, int partial, + int backup_root) { int fp; struct btrfs_fs_info *info; @@ -1127,7 +1161,7 @@ struct btrfs_fs_info *open_ctree_fs_info(const char *filename, return NULL; } info = __open_ctree_fd(fp, filename, sb_bytenr, root_tree_bytenr, - writes, partial, 0, 0); + writes, partial, 0, 0, backup_root); close(fp); return info; } @@ -1148,7 +1182,7 @@ struct btrfs_root *open_ctree_with_broken_super(const char *filename, return NULL; } info = __open_ctree_fd(fp, filename, sb_bytenr, 0, - writes, 0, 0, 1); + writes, 0, 0, 1, 0); close(fp); if (info) return info->fs_root; @@ -1159,7 +1193,7 @@ struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes) { struct btrfs_fs_info *info; - info = open_ctree_fs_info(filename, sb_bytenr, 0, writes, 0); + info = open_ctree_fs_info(filename, sb_bytenr, 0, writes, 0, 0); if (!info) return NULL; return info->fs_root; @@ -1169,7 +1203,7 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, int writes) { struct btrfs_fs_info *info; - info = __open_ctree_fd(fp, path, sb_bytenr, 0, writes, 0, 0, 0); + info = __open_ctree_fd(fp, path, sb_bytenr, 0, writes, 0, 0, 0, 0); if (!info) return NULL; return info->fs_root; |