Btrfs: do not call btrfs_update_inode in endio if nothing changed (1ef30be1) · Commits · 戴 / test

In the DIO code we often don't update the i_disk_size because the i_size isn't updated until after the DIO is completed, so basically we are allocating a path, doing a search, and updating the inode item for no reason since nothing changed. btrfs_ordered_update_i_size will return 1 if it didn't update i_disk_size, so only run btrfs_update_inode if btrfs_ordered_update_i_size returns 0. Thanks, Signed-off-by:

Josef Bacik <josef@redhat.com>

fs/btrfs/inode.c

+10 −5

Original line number	Diff line number	Diff line
		@@ -1769,9 +1769,12 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
		add_pending_csums(trans, inode, ordered_extent->file_offset,
		&ordered_extent->list);

		btrfs_ordered_update_i_size(inode, 0, ordered_extent);
		ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
		if (!ret) {
		ret = btrfs_update_inode(trans, root, inode);
		BUG_ON(ret);
		}
		ret = 0;
		out:
		if (nolock) {
		if (trans)
		@@ -5865,8 +5868,10 @@ again:
		}

		add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
		btrfs_ordered_update_i_size(inode, 0, ordered);
		ret = btrfs_ordered_update_i_size(inode, 0, ordered);
		if (!ret)
		btrfs_update_inode(trans, root, inode);
		ret = 0;
		out_unlock:
		unlock_extent_cached(&BTRFS_I(inode)->io_tree, ordered->file_offset,
		ordered->file_offset + ordered->len - 1,

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