From cf6ae7ed091059a8d1a70cf184f18ebfd18ab4af Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 26 Mar 2025 14:41:13 +1030 Subject: [PATCH] btrfs: subpage: access correct object when reading bitmap start in subpage_calc_start_bit() Inside the macro, subpage_calc_start_bit(), we need to calculate the offset to the beginning of the folio. But we're using offset_in_page(), on systems with 4K page size and 4K fs block size, this means we will always return offset 0 for a large folio, causing all kinds of errors. Fix it by using offset_in_folio() instead. Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/subpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 11dbd7be6a3b..bd252c78a261 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -204,7 +204,7 @@ static void btrfs_subpage_assert(const struct btrfs_fs_info *fs_info, btrfs_blocks_per_folio(fs_info, folio); \ \ btrfs_subpage_assert(fs_info, folio, start, len); \ - __start_bit = offset_in_page(start) >> fs_info->sectorsize_bits; \ + __start_bit = offset_in_folio(folio, start) >> fs_info->sectorsize_bits; \ __start_bit += blocks_per_folio * btrfs_bitmap_nr_##name; \ __start_bit; \ })