[PATCH RESEND 3/10] ext4: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

[Namjae Jeon]

2014-02-18 23:30 GMT+09:00, Theodore Ts'o <tytso at mit.edu>:
> Namjae,
Hi Ted.
>
> Did you respond to Matthew Wilcox's comments/question from Feb. 2nd?
Sorry, I didn't catch about this.
I just replied from Matthew's mail.
Thanks for your remind.
>
>> > What if the file is mmaped at the time somebody issues this command?
>> > Seems to me we should drop pagecache pages that overlap with the
>> > removed blocks.  If the removed range is not a multiple of PAGE_SIZE,
>> > then we should also drop any pagecache pages after the removed range.
>>
>> Oops, forgot to add "and if it is a multiple of page size, then we need
>> to update the offsets of any pages after the removed page".
>
> Dave responded that XFS does the right thing when doing a punch hole
> operation, but it wasn't obvious to me whether FL_COLLAPSE_RANGE does
> the right thing with ext4.
>
> Thanks,
>
> 					- Ted
>