Re: [PATCH 07/11] vfs: add nowait parameter for file_accessed()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 8/29/23 19:53, Matthew Wilcox wrote:
On Tue, Aug 29, 2023 at 03:46:13PM +0800, Hao Xu wrote:
On 8/28/23 05:32, Matthew Wilcox wrote:
On Sun, Aug 27, 2023 at 09:28:31PM +0800, Hao Xu wrote:
From: Hao Xu <howeyxu@xxxxxxxxxxx>

Add a boolean parameter for file_accessed() to support nowait semantics.
Currently it is true only with io_uring as its initial caller.

So why do we need to do this as part of this series?  Apparently it
hasn't caused any problems for filemap_read().


We need this parameter to indicate if nowait semantics should be enforced in
touch_atime(), There are locks and maybe IOs in it.

That's not my point.  We currently call file_accessed() and
touch_atime() for nowait reads and nowait writes.  You haven't done
anything to fix those.

I suspect you can trim this patchset down significantly by avoiding
fixing the file_accessed() problem.  And then come back with a later
patchset that fixes it for all nowait i/o.  Or do a separate prep series

I'm ok to do that.

first that fixes it for the existing nowait users, and then a second
series to do all the directory stuff.

I'd do the first thing.  Just ignore the problem.  Directory atime
updates cause I/O so rarely that you can afford to ignore it.  Almost
everyone uses relatime or nodiratime.

Hi Matthew,
The previous discussion shows this does cause issues in real
producations: https://lore.kernel.org/io-uring/2785f009-2ebb-028d-8250-d5f3a30510f0@xxxxxxxxx/#:~:text=fwiw%2C%20we%27ve%20just%20recently%20had%20similar%20problems%20with%20io_uring%20read/write







[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [NTFS 3]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [NTFS 3]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux