From 37f85ec320e6d73b92c8f8b5b2ddf33077970a23 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 13 Jun 2022 15:06:34 +0800 Subject: 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 Reviewed-by: David Sterba [ update changelog ] Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 80636fbf28b7..e6af960a6961 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1403,12 +1403,7 @@ static u64 dev_extent_search_start(struct btrfs_device *device, u64 start) { switch (device->fs_devices->chunk_alloc_policy) { case BTRFS_CHUNK_ALLOC_REGULAR: - /* - * We don't want to overwrite the superblock on the drive nor - * any area used by the boot loader (grub for example), so we - * make sure to start at an offset of at least 1MB. - */ - return max_t(u64, start, SZ_1M); + return max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED); case BTRFS_CHUNK_ALLOC_ZONED: /* * We don't care about the starting region like regular -- cgit v1.2.3-59-g8ed1b