From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: "Matthew Wilcox" <willy@infradead.org>,
linux-fsdevel@vger.kernel.org,
"Octavian Purdila" <octavian.purdila@intel.com>,
"Pantelis Antoniou" <pantelis.antoniou@konsulko.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Kai Mäkisara" <Kai.Makisara@kolumbus.fi>,
linux-scsi@vger.kernel.org
Subject: Re: [RFC] Re: broken userland ABI in configfs binary attributes
Date: Sat, 31 Aug 2019 14:35:37 +0100 [thread overview]
Message-ID: <20190831133537.GX1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190831083241.GC28527@lst.de>
On Sat, Aug 31, 2019 at 10:32:41AM +0200, Christoph Hellwig wrote:
> On Mon, Aug 26, 2019 at 08:28:19PM +0100, Al Viro wrote:
> > For configfs bin_attr it won't work, simply because it wants the entire
> > thing to be present - callback parses the data. For SCSI tape... Maybe,
> > but you'll need to take care of the overlaps with ->write(). Right now
> > it can't happen (the last reference, about to be dropped right after
> > st_flush() returns); if we do that on each ->flush(), we will have to
> > cope with that fun and we'll need to keep an error (if any) for the
> > next call of st_flush() to pick and return. I'm not saying it can't
> > be done, but that's really a question for SCSI folks.
>
> So for the one real life example of the configfs attribute life
> actually is simpler. acpi_table_aml_write verifies early on that
> the size matches what it expects. So if we document that any future
> instance needs to be able to do that as well we should be able to
> get away with just writing it from ->flush.
I'm not sure I understand what you mean... Do you want them to recognize
incomplete data and quietly bugger off when called on too early ->flush()?
next prev parent reply other threads:[~2019-08-31 13:35 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 2:48 broken userland ABI in configfs binary attributes Al Viro
2019-08-26 16:29 ` [RFC] " Al Viro
2019-08-26 18:20 ` Matthew Wilcox
2019-08-26 19:28 ` Al Viro
2019-08-27 8:51 ` Miklos Szeredi
2019-08-27 11:58 ` Al Viro
2019-08-27 12:21 ` Miklos Szeredi
2019-08-27 12:53 ` Al Viro
2019-08-31 8:32 ` Christoph Hellwig
2019-08-31 13:35 ` Al Viro [this message]
2019-08-31 14:44 ` Christoph Hellwig
2019-08-31 15:58 ` Al Viro
2019-08-26 18:34 ` "Kai Mäkisara (Kolumbus)"
2019-08-26 19:32 ` Al Viro
2019-08-27 15:01 ` Boaz Harrosh
2019-08-27 17:27 ` Al Viro
2019-08-27 17:59 ` Boaz Harrosh
2019-08-29 22:22 ` Al Viro
2019-08-29 23:32 ` Al Viro
2019-08-30 4:10 ` Dave Chinner
2019-08-30 4:44 ` Al Viro
2019-08-31 8:28 ` Christoph Hellwig
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