Btrfs: readahead checksums during btrfs_finish_ordered_io (5d13a98f) · Commits · 戴 / test

fs/btrfs/inode.c

+33 −2

Original line number	Diff line number	Diff line
		@@ -1497,6 +1497,30 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
		return 0;
		}

		/*
		* helper function for btrfs_finish_ordered_io, this
		* just reads in some of the csum leaves to prime them into ram
		* before we start the transaction. It limits the amount of btree
		* reads required while inside the transaction.
		*/
		static noinline void reada_csum(struct btrfs_root *root,
		struct btrfs_path *path,
		struct btrfs_ordered_extent *ordered_extent)
		{
		struct btrfs_ordered_sum *sum;
		u64 bytenr;

		sum = list_entry(ordered_extent->list.next, struct btrfs_ordered_sum,
		list);
		bytenr = sum->sums[0].bytenr;

		/*
		* we don't care about the results, the point of this search is
		* just to get the btree leaves into ram
		*/
		btrfs_lookup_csum(NULL, root->fs_info->csum_root, path, bytenr, 0);
		}

		/* as ordered data IO finishes, this gets called so we can finish
		* an ordered extent if the range of bytes in the file it covers are
		* fully written.
		@@ -1505,7 +1529,7 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
		{
		struct btrfs_root *root = BTRFS_I(inode)->root;
		struct btrfs_trans_handle *trans;
		struct btrfs_ordered_extent *ordered_extent;
		struct btrfs_ordered_extent *ordered_extent = NULL;
		struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
		struct btrfs_path *path;
		int compressed = 0;
		@@ -1528,12 +1552,19 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
		ret = btrfs_lookup_file_extent(NULL, root, path,
		inode->i_ino,
		start, 0);
		ordered_extent = btrfs_lookup_ordered_extent(inode,
		start);
		if (!list_empty(&ordered_extent->list)) {
		btrfs_release_path(root, path);
		reada_csum(root, path, ordered_extent);
		}
		btrfs_free_path(path);
		}
		}

		trans = btrfs_join_transaction(root, 1);

		if (!ordered_extent)
		ordered_extent = btrfs_lookup_ordered_extent(inode, start);
		BUG_ON(!ordered_extent);
		if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))

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