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From: Dominique Martinet <asmadeus@codewreck.org>
To: Christian Kastner <ckk@debian.org>
Cc: David Howells <dhowells@redhat.com>,
	Andrea Righi <andrea.righi@canonical.com>,
	Eric Van Hensbergen <ericvh@kernel.org>,
	linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org,
	v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Luca Boccassi <bluca@debian.org>, TJ <linux@iam.tj>,
	Emanuele Rocca <ema@debian.org>
Subject: Re: [PATCH v5 40/40] 9p: Use netfslib read/write_iter
Date: Tue, 18 Jun 2024 06:50:01 +0900	[thread overview]
Message-ID: <ZnCviUrk5iQGrE4x@codewreck.org> (raw)
In-Reply-To: <57e56ca5-bbbc-495a-926e-54d7e2f5e76c@debian.org>

Christian Kastner wrote on Mon, Jun 17, 2024 at 07:10:56PM +0200:
> On 2024-05-31 17:06, Emanuele Rocca wrote:
> > Meanwhile TJ (in CC) has been doing a lot of further investigation and
> > opened https://bugzilla.kernel.org/show_bug.cgi?id=218916.
> 
> just to loop back to the MLs: in the referenced bug, TJ posted an
> analysis and and added a patch that fixed the issue for multiple testers.

Thanks for the mail, one of these days I'll try to understand how to
make bugzilla automatically put me in cc of all the 9p bugs..

Analysis and tentative fix are of great help! Looks like we now
understand what's wrong -- if I understand the description correctly we
know the correct size (files aren't modified in the background, just
other threads within the VM, right?); and the problem is that the netfs
IO reverts the size back to an incorrect value when it completes?

If so then the fix looks odd to me, the problem ought to be fixed at the
netfs/9p interface level, I don't see why an unbuffered read should
update the size metadata when it's done...

David, what do you think?

-- 
Dominique Martinet | Asmadeus

  reply	other threads:[~2024-06-17 21:50 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-21 13:22 [PATCH v5 00/40] netfs, afs, 9p: Delegate high-level I/O to netfslib David Howells
2023-12-21 13:22 ` [PATCH v5 01/40] afs: Remove whitespace before most ')' from the trace header David Howells
2023-12-21 13:22 ` [PATCH v5 02/40] afs: Automatically generate trace tag enums David Howells
2023-12-21 13:22 ` [PATCH v5 03/40] netfs, fscache: Move fs/fscache/* into fs/netfs/ David Howells
2023-12-21 13:22 ` [PATCH v5 04/40] netfs, fscache: Combine fscache with netfs David Howells
2023-12-21 13:23 ` [PATCH v5 05/40] netfs, fscache: Remove ->begin_cache_operation David Howells
2023-12-21 13:23 ` [PATCH v5 06/40] netfs, fscache: Move /proc/fs/fscache to /proc/fs/netfs and put in a symlink David Howells
2024-01-03 16:49   ` Marc Dionne
2023-12-21 13:23 ` [PATCH v5 07/40] netfs: Move pinning-for-writeback from fscache to netfs David Howells
2023-12-21 13:23 ` [PATCH v5 08/40] netfs: Add a procfile to list in-progress requests David Howells
2023-12-21 13:23 ` [PATCH v5 09/40] netfs: Allow the netfs to make the io (sub)request alloc larger David Howells
2023-12-21 13:23 ` [PATCH v5 10/40] netfs: Add a ->free_subrequest() op David Howells
2023-12-21 13:23 ` [PATCH v5 11/40] afs: Don't use folio->private to record partial modification David Howells
2023-12-21 13:23 ` [PATCH v5 12/40] netfs: Provide invalidate_folio and release_folio calls David Howells
2023-12-21 13:23 ` [PATCH v5 13/40] netfs: Implement unbuffered/DIO vs buffered I/O locking David Howells
2023-12-21 13:23 ` [PATCH v5 14/40] netfs: Add iov_iters to (sub)requests to describe various buffers David Howells
2024-08-08  8:07   ` Christian Ebner
2024-08-12 13:01     ` Christian Ebner
2023-12-21 13:23 ` [PATCH v5 15/40] netfs: Add support for DIO buffering David Howells
2023-12-26 16:54   ` Nathan Chancellor
2023-12-28 10:47     ` Christian Brauner
2023-12-28 16:58       ` Nathan Chancellor
2023-12-21 13:23 ` [PATCH v5 16/40] netfs: Provide tools to create a buffer in an xarray David Howells
2023-12-21 13:23 ` [PATCH v5 17/40] netfs: Add func to calculate pagecount/size-limited span of an iterator David Howells
2023-12-21 13:23 ` [PATCH v5 18/40] netfs: Limit subrequest by size or number of segments David Howells
2023-12-21 13:23 ` [PATCH v5 19/40] netfs: Extend the netfs_io_*request structs to handle writes David Howells
2023-12-21 13:23 ` [PATCH v5 20/40] netfs: Add a hook to allow tell the netfs to update its i_size David Howells
2023-12-21 13:23 ` [PATCH v5 21/40] netfs: Make netfs_put_request() handle a NULL pointer David Howells
2023-12-21 13:23 ` [PATCH v5 22/40] netfs: Make the refcounting of netfs_begin_read() easier to use David Howells
2023-12-21 13:23 ` [PATCH v5 23/40] netfs: Prep to use folio->private for write grouping and streaming write David Howells
2023-12-21 13:23 ` [PATCH v5 24/40] netfs: Dispatch write requests to process a writeback slice David Howells
2023-12-21 13:23 ` [PATCH v5 25/40] netfs: Provide func to copy data to pagecache for buffered write David Howells
2023-12-21 13:23 ` [PATCH v5 26/40] netfs: Make netfs_read_folio() handle streaming-write pages David Howells
2023-12-21 13:23 ` [PATCH v5 27/40] netfs: Allocate multipage folios in the writepath David Howells
2023-12-21 13:23 ` [PATCH v5 28/40] netfs: Implement unbuffered/DIO read support David Howells
2023-12-21 13:23 ` [PATCH v5 29/40] netfs: Implement unbuffered/DIO write support David Howells
2023-12-21 13:23 ` [PATCH v5 30/40] netfs: Implement buffered write API David Howells
2023-12-21 13:23 ` [PATCH v5 31/40] netfs: Allow buffered shared-writeable mmap through netfs_page_mkwrite() David Howells
2023-12-21 13:23 ` [PATCH v5 32/40] netfs: Provide netfs_file_read_iter() David Howells
2023-12-21 13:23 ` [PATCH v5 33/40] netfs, cachefiles: Pass upper bound length to allow expansion David Howells
2024-01-02 14:04   ` Gao Xiang
2024-01-02 17:11   ` David Howells
2024-01-02 20:37     ` Gao Xiang
2024-01-03 10:15     ` Jia Zhu
2023-12-21 13:23 ` [PATCH v5 34/40] netfs: Provide a writepages implementation David Howells
2023-12-21 13:23 ` [PATCH v5 35/40] netfs: Provide a launder_folio implementation David Howells
2023-12-21 13:23 ` [PATCH v5 36/40] netfs: Implement a write-through caching option David Howells
2023-12-21 13:23 ` [PATCH v5 37/40] netfs: Optimise away reads above the point at which there can be no data David Howells
2023-12-21 23:01   ` Nathan Chancellor
2023-12-22 11:49   ` David Howells
2023-12-22 12:00   ` [PATCH] Fix oops in NFS David Howells
2024-01-05  4:52     ` Matthew Wilcox
2024-01-05 10:12     ` David Howells
2024-01-05 13:17       ` Matthew Wilcox
2024-01-05 17:20         ` Dominique Martinet
2024-01-05 11:48     ` David Howells
2024-01-05 14:33     ` David Howells
2023-12-21 13:23 ` [PATCH v5 38/40] netfs: Export the netfs_sreq tracepoint David Howells
2023-12-21 13:23 ` [PATCH v5 39/40] afs: Use the netfs write helpers David Howells
2023-12-21 13:23 ` [PATCH v5 40/40] 9p: Use netfslib read/write_iter David Howells
2024-01-03  7:22   ` Dominique Martinet
2024-01-03 19:52     ` Eric Van Hensbergen
2024-01-03 12:08   ` David Howells
2024-01-03 12:39   ` David Howells
2024-01-03 13:00     ` Dominique Martinet
2024-05-09 17:15   ` Andrea Righi
2024-05-09 21:33   ` David Howells
2024-05-10  5:53     ` Andrea Righi
2024-05-10  7:57     ` David Howells
2024-05-23  7:44   ` David Howells
2024-05-30 19:16     ` Emanuele Rocca
2024-05-31 15:06     ` Emanuele Rocca
2024-06-17 17:10       ` Christian Kastner
2024-06-17 21:50         ` Dominique Martinet [this message]
2023-12-22 13:02 ` [PATCH] Fix EROFS Kconfig David Howells
2023-12-23  3:55   ` Jingbo Xu
2023-12-23 13:32     ` Gao Xiang
2024-01-02 15:39 ` [PATCH v5 40/40] 9p: Use netfslib read/write_iter David Howells
2024-01-02 21:49 ` [PATCH] 9p: Fix initialisation of netfs_inode for 9p David Howells
2024-01-03 13:10   ` Dominique Martinet
2024-01-03 13:59   ` David Howells
2024-01-03 14:04   ` David Howells

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