在 2024/5/3 21:55, Anand Jain 写道:
[...]
+int find_prealloc(struct blk_iterate_data *data, int index, bool
*prealloc)
This function is called for every file extent we're going to create.
I'm not a big fan of doing so many lookup.
My question is, is this the only way to determine the flag of the data
extent?
My instinct says there should be a straight forward way to determine
if a file extent is preallocated or not, just like what we do in our
file extent items.
Thus during the ext2fs_block_iterate2(), there should be some way to
tell if a block is preallocated or not.
Unfortunately, the callback doesn't provide the extent flags. Unless, I
miss something?
You're right, the iterator interface does not provide any extra info.
And I also checked the kernel implementation, they have extra
ext4_map_blocks() to do the resolve, and then ext4_es_lookup_extent() to
determine if it's unwritten.
So I'm afraid we have to go this solution.
Meanwhile related to the implementation, can we put the prealloc flat
into blk_iterate_data?
So that we can handle different fses' preallocated extents in a more
common way.
Thanks,
Qu
