From: "chenxiaosong (A)" <chenxiaosong2@huawei.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
"anna@kernel.org" <anna@kernel.org>,
"smayhew@redhat.com" <smayhew@redhat.com>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"liuyongqiang13@huawei.com" <liuyongqiang13@huawei.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"yi.zhang@huawei.com" <yi.zhang@huawei.com>,
"zhangxiaoxu5@huawei.com" <zhangxiaoxu5@huawei.com>
Subject: Re: [PATCH -next 1/2] nfs: nfs{,4}_file_flush should consume writeback error
Date: Tue, 12 Apr 2022 22:12:57 +0800 [thread overview]
Message-ID: <ccd017a4-31f1-297f-b2e2-e71eb16f1159@huawei.com> (raw)
In-Reply-To: <0528423f710cd612262666b1533763943c717273.camel@hammerspace.com>
在 2022/4/12 21:56, Trond Myklebust 写道:
> On Tue, 2022-04-12 at 21:46 +0800, chenxiaosong (A) wrote:
>>
>> Other filesystem will _not_ clear writeback error on close().
>> And other filesystem will _not_ clear writeback error on async
>> write() too.
>>
>> Other filesystem _only_ clear writeback error on fsync() or sync
>> write().
>>
>
> Yes. We might even consider not reporting writeback errors at all in
> close(), since most developers don't check it. We certainly don't want
> to clear those errors there because the manpages don't document that as
> being the case.
>
>> Should NFS follow the same semantics as all the other filesystems?
>
> It needs to follow the semantics described in the manpage for write(2)
> and fsync(2) as closely as possible, yes. That documentation is
> supposed to be normative for application developers.
>
> We won't guarantee to immediately report ENOSPC like other filesystems
> do (because that would require us to only support synchronous writes),
> however that behaviour is already documented in the manpage.
>
> We may also report some errors that are not documented in the manpage
> (e.g. EACCES or EROFS) simply because those errors cannot always be
> reported at open() time, as would be the case for a local filesystem.
> That's just how the NFS protocol works (particularly for the case of
> the stateless NFSv3 protocol).
>
After merging your patchset, NFS will clear wb error on async write(),
is this reasonable?
And more importantly, we can not detect new error by using
filemap_sample_wb_err()/filemap_sample_wb_err() while nfs_wb_all(),just
as I described:
```c
since = filemap_sample_wb_err() = 0
errseq_sample
if (!(old & ERRSEQ_SEEN)) // nobody see the error
return 0;
nfs_wb_all // no new error
error = filemap_check_wb_err(..., since) != 0 // unexpected error
```
next prev parent reply other threads:[~2022-04-12 14:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-05 12:46 [PATCH -next 0/2] nfs: check writeback errors correctly ChenXiaoSong
2022-03-05 12:46 ` [PATCH -next 1/2] nfs: nfs{,4}_file_flush should consume writeback error ChenXiaoSong
2022-03-05 16:53 ` Trond Myklebust
2022-03-06 3:54 ` chenxiaosong (A)
2022-03-06 14:04 ` Trond Myklebust
2022-03-06 15:08 ` Trond Myklebust
2022-04-12 13:46 ` chenxiaosong (A)
2022-04-12 13:56 ` Trond Myklebust
2022-04-12 14:12 ` chenxiaosong (A) [this message]
2022-04-12 14:27 ` Trond Myklebust
2022-04-20 8:50 ` chenxiaosong (A)
2022-05-09 7:43 ` chenxiaosong (A)
2022-03-05 12:46 ` [PATCH -next 2/2] nfs: nfs_file_write() check writeback errors correctly ChenXiaoSong
2022-03-05 17:12 ` Trond Myklebust
2022-03-06 8:50 ` chenxiaosong (A)
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