Re: [PATCH 28/28] quota: add extra inode count to dquot transfer functions

From: Tahsin Erdogan
Date: Mon Jun 19 2017 - 07:46:17 EST

>> I tried that approach by adding a "int get_inode_usage(struct inode
>> *inode, qsize_t *usage)" callback to dquot_operations. Unfortunately,
>> ext4 code that calculates the number of internal inodes
>> (ext4_xattr_inode_count()) is subject to failures so the callback has
>> to be able to report errors. And, that itself is problematic because
>> we can't afford to have errors in dquot_free_inode(). If you have
>> thoughts about how to address this please let me know.
> Well, you can just make dquot_free_inode() return error. Now most callers
> won't be able to do much with an error from dquot_free_inode() but that's
> the case also for other things during inode deletion - just handle it as
> other fatal failures during inode freeing.
I just checked dquot_free_inode() to see whether it calls anything
that could fail. It calls mark_all_dquot_dirty() and ignores the
return code from it. I would like to follow the same for the
get_inode_usage() as the only use case for get_inode_usage() (ext4)
should not fail at inode free time.

Basically, I want to avoid changing return type from void to int
because it would create a new responsibility for the filesystem
implementations who do not know how to deal with it.