Re: [f2fs-dev] [RFC PATCH 3/9] f2fs: support regular file buffered writes on large folios

On 7/10/26 15:44, Nanzhe Zhao wrote:
>>> Both the error path and the normal path will eventually reach the out label path,
>>> and out will call f2fs_put_dnode(&dn) if get_dn is true.
>>> Or am I missing something?
>>
>> For above case: both head and tail has partial updated data, then we call
>> f2fs_get_dnode_of_data() twice, but call f2fs_put_dnode() once?
> 
> I think f2fs_put_dnode() will be called twice in that case.
> 
> The out label is still inside the while loop body. For each block returned by

It's not in 3/9 at least:

+	}
+
+out:
+		if (get_dn)
+			f2fs_put_dnode(&dn);
+
+		return err;
+}

> f2fs_find_next_need_read_block(), get_dn is reset to false first. If
> f2fs_get_dnode_of_data() succeeds, get_dn is set to true, and the same
> iteration will fall through/goto out and call f2fs_put_dnode(&dn).
> 
> So for head and tail, the flow should be:
> 
> head: get dnode -> read/zero -> out -> put dnode
> tail: get dnode -> read/zero -> out -> put dnode
> 
> If head and tail are the same block, the first iteration marks it uptodate,
> so the next f2fs_find_next_need_read_block() will not return it again.
> 
> Hmmm, if the current control flow is so easy to misread, would you like me
> to change it a bit to make the per-iteration dnode lifetime more obvious?
> 
> Thanks,
> 



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