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| author | Qu Wenruo <wqu@suse.com> | 2022-06-13 10:06:34 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2022-07-25 18:45:36 +0300 |
| commit | 37f85ec320e6d73b92c8f8b5b2ddf33077970a23 (patch) | |
| tree | 45bf2097d56215c00b0ca9766e3e878ca4d989c7 /fs/btrfs/extent-tree.c | |
| parent | bfceac7fd3c47175fec75c32071051de5969a34c (diff) | |
| download | linux-37f85ec320e6d73b92c8f8b5b2ddf33077970a23.tar.xz | |
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/extent-tree.c')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 91d2c20c7c8a..a1696e3ffb1e 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5976,7 +5976,7 @@ int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, */ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed) { - u64 start = SZ_1M, len = 0, end = 0; + u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0; int ret; *trimmed = 0; @@ -6020,8 +6020,8 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed) break; } - /* Ensure we skip the reserved area in the first 1M */ - start = max_t(u64, start, SZ_1M); + /* Ensure we skip the reserved space on each device. */ + start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED); /* * If find_first_clear_extent_bit find a range that spans the |