From: Qu Wenruo Date: Mon, 26 Jul 2021 06:34:52 +0000 (+0800) Subject: btrfs: disable compressed readahead for subpage X-Git-Tag: baikal/mips/sdk5.9~10259^2~76 X-Git-Url: https://git.baikalelectronics.ru/?a=commitdiff_plain;h=e2fa709a9347deea1db684b31e7c5bc3cd642bb5;p=kernel.git btrfs: disable compressed readahead for subpage For current subpage support, we only support 64K page size with 4K sector size. This makes compressed readahead less effective, as maximum compressed extent size is only 128K, 2x the page size. On the other hand, the function add_ra_bio_pages() is still assuming sectorsize == PAGE_SIZE, and code change may affect 4K page size systems. So for now, let's disable subpage compressed readahead for now. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index aeda426b61211..18579b904d5c3 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -564,6 +564,16 @@ static noinline int add_ra_bio_pages(struct inode *inode, if (isize == 0) return 0; + /* + * For current subpage support, we only support 64K page size, + * which means maximum compressed extent size (128K) is just 2x page + * size. + * This makes readahead less effective, so here disable readahead for + * subpage for now, until full compressed write is supported. + */ + if (btrfs_sb(inode->i_sb)->sectorsize < PAGE_SIZE) + return 0; + end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; while (last_offset < compressed_end) {