btrfs: reduce pointer intdirections in btree_readpage_end_io_hook (15b6e8a8) · Commits · 戴 / test

All we need to read is checksum size from fs_info superblock, and fs_info is provided by extent buffer so we can get rid of the wild pointer indirections from page/inode/root. Reviewed-by:

Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:

David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -604,9 +604,8 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
		u64 found_start;
		int found_level;
		struct extent_buffer *eb;
		struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
		struct btrfs_fs_info *fs_info = root->fs_info;
		u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
		struct btrfs_fs_info *fs_info;
		u16 csum_size;
		int ret = 0;
		u8 result[BTRFS_CSUM_SIZE];
		int reads_done;
		@@ -615,6 +614,8 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
		goto out;

		eb = (struct extent_buffer *)page->private;
		fs_info = eb->fs_info;
		csum_size = btrfs_super_csum_size(fs_info->super_copy);

		/* the pending IO might have been the only thing that kept this buffer
		* in memory. Make sure we have a ref for all this other checks

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