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Tue, 9 Apr 2024 06:09:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id rJfbLrXbFGamKQAAD6G6ig (envelope-from ); Tue, 09 Apr 2024 06:09:57 +0000 Message-ID: <6ef177d7-a565-4ddb-8522-81ffbfb5380e@suse.de> Date: Tue, 9 Apr 2024 08:09:57 +0200 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: API break, sysfs "capability" file Content-Language: en-US To: Keith Busch , Lennart Poettering Cc: Linux regressions mailing list , Christoph Hellwig , linux-block@vger.kernel.org, LKML , Jens Axboe References: <54e3c969-3ee8-40d8-91d9-9b9402001d27@leemhuis.info> From: Hannes Reinecke In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Level: X-Spamd-Result: default: False [-1.52 / 50.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; BAYES_HAM(-0.23)[72.47%]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; XM_UA_NO_VERSION(0.01)[]; RCPT_COUNT_SEVEN(0.00)[7]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Spam-Score: -1.52 X-Spam-Flag: NO On 4/9/24 00:41, Keith Busch wrote: > On Mon, Apr 08, 2024 at 10:23:49PM +0200, Lennart Poettering wrote: >> Not sure how this is salvageable. This is just seriously fucked >> up. What now? >> >> It has been proposed to use the "range_ext" sysfs attr instead as a >> hint if partition scanning is available or not. But it's entirely >> undocumented. Is this something that will remain stable? (I mean, >> whether something is documented or not apparently has no effect on the >> stability of an API anyway, so I guess it's equally shaky as the >> capability sysattr? Is any of the block device sysfs interfaces >> actually stable or can they change any time?) > > The "ext_range" attribute does look like an appropriate proxy for the > attribute, but indeed, it's not well documented. > > Looking at the history of the documentation you had been relying on, it > appears that was submitted with good intentions (9243c6f3e012a92d), but > it itself changed values, acknowledging the instability of this > interface. > > So what to do? If documentation is all that's preventing "ext_range" > from replacing you're previous usage, then let's add it in the > Documentation/ABI/stable/sysfs-block. It's been there since 2008, so > that seems like a reliable attribute to put there. > I'll side with Keith. Our management tools use 'ext_range' to find if a device is partitionable, and we've done that since the very beginning of sysfs. Cheers, Hannes