Messages in this thread | | | Date | Mon, 26 Jun 2023 13:16:26 +0100 | From | Matthew Wilcox <> | Subject | Re: f2fs async buffered write patch |
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On Mon, Jun 26, 2023 at 03:31:57PM +0800, Yangtao Li wrote: > +cc willy@infradead.org > > > On 2023/6/20 4:43, Jens Axboe wrote: > > > Hi, > > > > I came across this patch in a news posting: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=d618126911829523e35a61f4a5a4ad159b1b2c8d > > > > which has me a bit worried. As far as I can tell, all that patch does is > > set FMODE_BUF_WASYNC, and then just hope that the lower layers handle > > the rest? > > > > What happens if iocb->ki_flags & IOCB_NOWAIT is true, and now we do: > > > > generic_perform_write(iocb, from) > > ... > > ->write_begin() <- does this block? > > Most file systems have not been changed to the iomap method,
That's what needs to be fixed.
> and the generic_perform_write method is still used. So it seems > > reasonable to make IOCB_NOWAIT be handled correctly by the > > generic_perform_write function. This means that we need to modify
No. Use the modern infrastructure.
> several places mentioned by Jens in the generic_perform_write function, > > and need to pass AOP_FLAG_xxx or iocb into write_begin.
Definitely not.
> > I noticed that Matthew Wilcox removed the flags parameter in write_begin > > in a previous commit, maybe we can add it back?
No.
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