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| author | Yan Zheng <zheng.yan@oracle.com> | 2008-12-08 16:46:26 -0500 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2008-12-08 16:46:26 -0500 |
| commit | a512bbf855ff0af474257475f2e6da7acd854f52 (patch) | |
| tree | 1b2cfcf4152e09f32a6cb0bcbd798d5dab2f5490 /fs/btrfs/disk-io.h | |
| parent | d20f7043fa65659136c1a7c3c456eeeb5c6f431f (diff) | |
Btrfs: superblock duplication
This patch implements superblock duplication. Superblocks
are stored at offset 16K, 64M and 256G on every devices.
Spaces used by superblocks are preserved by the allocator,
which uses a reverse mapping function to find the logical
addresses that correspond to superblocks. Thank you,
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.h')
| -rw-r--r-- | fs/btrfs/disk-io.h | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 717e94811e4..c0ff404c31b 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -19,8 +19,20 @@ #ifndef __DISKIO__ #define __DISKIO__ -#define BTRFS_SUPER_INFO_OFFSET (16 * 1024) +#define BTRFS_SUPER_INFO_OFFSET (64 * 1024) #define BTRFS_SUPER_INFO_SIZE 4096 + +#define BTRFS_SUPER_MIRROR_MAX 3 +#define BTRFS_SUPER_MIRROR_SHIFT 12 + +static inline u64 btrfs_sb_offset(int mirror) +{ + u64 start = 16 * 1024; + if (mirror) + return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror); + return BTRFS_SUPER_INFO_OFFSET; +} + struct btrfs_device; struct btrfs_fs_devices; @@ -37,7 +49,8 @@ struct btrfs_root *open_ctree(struct super_block *sb, char *options); int close_ctree(struct btrfs_root *root); int write_ctree_super(struct btrfs_trans_handle *trans, - struct btrfs_root *root); + struct btrfs_root *root, int max_mirrors); +struct buffer_head *btrfs_read_dev_super(struct block_device *bdev); int btrfs_commit_super(struct btrfs_root *root); struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize); |