diff options
| author | Qu Wenruo | 2022-06-13 15:06:34 +0800 |
|---|---|---|
| committer | David Sterba | 2022-07-25 17:45:36 +0200 |
| commit | 37f85ec320e6d73b92c8f8b5b2ddf33077970a23 (patch) | |
| tree | 45bf2097d56215c00b0ca9766e3e878ca4d989c7 /fs/btrfs/ctree.h | |
| parent | bfceac7fd3c47175fec75c32071051de5969a34c (diff) | |
btrfs: use named constant for reserved device space
There's a reserved space on each device of size 1MiB that can be used by
bootloaders or to avoid accidental overwrite. Use a symbolic constant
with the explaining comment instead of hard coding the value and
multiple comments.
Note: since btrfs-progs v4.1, mkfs.btrfs will reserve the first 1MiB for
the primary super block (at offset 64KiB), until then the range could
have been used by mistake. Kernel has been always respecting the 1MiB
range for writes.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ctree.h')
| -rw-r--r-- | fs/btrfs/ctree.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index e5f19b49efa8..6d9f81d4e99c 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -230,6 +230,13 @@ struct btrfs_root_backup { #define BTRFS_SUPER_INFO_SIZE 4096 /* + * The reserved space at the beginning of each device. + * It covers the primary super block and leaves space for potential use by other + * tools like bootloaders or to lower potential damage of accidental overwrite. + */ +#define BTRFS_DEVICE_RANGE_RESERVED (SZ_1M) + +/* * the super block basically lists the main trees of the FS * it currently lacks any block count etc etc */ |