From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=195.135.223.131 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794587455; b=op1TQY2U7JzaNSa+RR4NJaK9WdhS04wlr0kFqs5vNn6mRUI1605TWK1m2q9jCLISABZd vFpS8SZNMztVKC4H/B2cEXWAa+kh7H1lJacPDn05IqS02x2xHhhnJT6ajgM83W6GMC/qk YE4f7mErTGQL9UxKwr9VLOyR0U/IlMthI4yIgdWybz/10KsYt5Ifk5AeSVyJj28bX8Jrc 5qSk/ycjIOLALwze2N4JfzqrtoJKUoL1PFnLePTl07xxoZZ20YYfQA/hfWxHS9Fv/7OdJ aQslsAPIKkbb53POcmeeeQz/xDpmpBg/7zyMMgRJMDjejvHQIU/0nZcJsIzGkQ3FBqg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794587455; h=DMARC-Filter:Received:DKIM-Signature:DKIM-Signature:DKIM-Signature: DKIM-Signature:Received:Received:Date:From:To:Cc:Subject:Message-ID: Reply-To:References:MIME-Version:Content-Type:Content-Disposition: Content-Transfer-Encoding:In-Reply-To:User-Agent:X-Spamd-Result: X-Spam-Score:X-Spam-Level:X-Spam-Flag; bh=SFq8ddNJzc006WJhU0yarY6wE/1nnfxn+pbXXQhjiVY=; b=uyxz2cWo6Vij9z1NXjeps1MMRhiPr93PF4WJqimXvgdfDzwiCNONQu8PtjqVss3zCVmD KH/jTaItmj2hrIVv+r5ihKw/8WVAJa4I97jGlE3PSi9pCh11p1alumjdpBJ6Yh+WsuDbs jzkgKeBiUCFvTfCmHEUK0ARKSAm4239zQT6HpBlSB7NcJJRkMNyiCBSqSSFldbTsKw8Hx hzKIMiK0sWELUuOhq8nhOO2KyMA5QjO/+wF2o0JDrx47sXcHjmViSbucawEJtdhnVcYdE XHVoqDoiP6j1gC+toaHDntBVVk6DLSNaNxhm7KWEADKn0oPikEf64b98frxS11u/mKw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256 header.s=susede2_rsa header.b=2lHI1mCM; dkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=NFY8lT4T; dkim=pass header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256 header.s=susede2_rsa header.b=utyDHd+e; dkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256 header.s=susede2_ed25519 header.b="Fy7/yVF7"; arc=none smtp.remote-ip=195.135.223.131 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DA8A606A32D; Fri, 13 Nov 2026 16:30:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5DA8A606A32D Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256 header.s=susede2_rsa header.b=2lHI1mCM; dkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=NFY8lT4T; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256 header.s=susede2_rsa header.b=utyDHd+e; dkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=Fy7/yVF7 Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 5AC071F74C; Fri, 13 Nov 2026 16:30:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1794587452; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SFq8ddNJzc006WJhU0yarY6wE/1nnfxn+pbXXQhjiVY=; b=2lHI1mCMiKdtTNfiDYhbrcWS8MtNJOw10T+JuhPVk5dEHrd/qr3IxEpLsUT/yDbWe1Jcw/ lmyyQAE0u3fTc8QUQeCZKKYZT6Rs3N8GiJHzY+5QtGjs6S8rpfoi45PeilfAF2JnFAvLmi fYyqMi2Dc98pvp7LNhIgAjo2NjqdAEc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1794587452; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SFq8ddNJzc006WJhU0yarY6wE/1nnfxn+pbXXQhjiVY=; b=NFY8lT4TMS324TlTVzvC0XdyT2YZ+9rYr0sev27+R9Qrhpi26YJryCw7j7tjb35v+clNys unn2K/GuC3BpunCA== Authentication-Results: smtp-out2.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1794587451; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SFq8ddNJzc006WJhU0yarY6wE/1nnfxn+pbXXQhjiVY=; b=utyDHd+elflaW8pX1u1nfL/l0o/6c6U0vfLc5XrUHqwBMZ/c3JfeEmP4/04tPGVJEUz8pu +7xpJ//2v5EAeYUjeLwup+jTdIpH+VKmvwC+38fH0CxQMBeA247HiQXZL1mGgjBK4LcyRf 4hFNM3kMWg7LM4C34Q08vWmkP5usz/M= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1794587451; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SFq8ddNJzc006WJhU0yarY6wE/1nnfxn+pbXXQhjiVY=; b=Fy7/yVF76B1GwHUbGL3CvO22WfKSoXA6fxwJ8d3OYUW/Ef4aXV95LCWDM5R7hkICraKKw3 7Yw9ffB99G0aSZBQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 1ECDC134F4; Fri, 13 Nov 2026 16:30:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id E45zOjo792rddgAAD6G6ig (envelope-from ); Fri, 13 Nov 2026 16:30:51 +0000 Date: Fri, 13 Nov 2026 17:30:49 +0100 From: David Sterba To: Qu Wenruo Cc: Cheng Yongkang , David Sterba , Chris Mason , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] btrfs: reject refs=0 subvolume without DEAD in SUBVOL_SYNC_WAIT Message-ID: <20261113163049.GA49432@suse.cz> Reply-To: dsterba@suse.cz References: <20261101062539.1744605-1-teel4res@gmail.com> <20261109184712.GF4186782@twin.jikos.cz> <70aa1a4e-895b-416f-a3cb-195af489b55e@suse.com> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <70aa1a4e-895b-416f-a3cb-195af489b55e@suse.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) X-Spamd-Result: default: False [-13.00 / 50.00]; SUSE_INTERNAL_BYPASS(-9.00)[]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; HAS_REPLYTO(0.30)[dsterba@suse.cz]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_SEVEN(0.00)[7]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[gmail.com,suse.com,kernel.org,vger.kernel.org]; MID_RHS_MATCH_FROM(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; REPLYTO_ADDR_EQ_FROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.cz:replyto] X-Spam-Score: -13.00 X-Spam-Level: X-Spam-Flag: NO On Tue, Nov 10, 2026 at 07:00:34AM +1030, Qu Wenruo wrote: > > > 在 2026/11/10 05:17, David Sterba 写道: > > On Sun, Nov 01, 2026 at 05:48:21PM +1030, Qu Wenruo wrote: > >> With that said, there are more problems with the ioctl. > >> > >> - No real user > >> No one is utilizing BTRFS_SUBVOL_SYNC* flags. Btrfs-progs itself > >> doesn't even bother it. > >> > >> So all these fixes are very low priority, unless there are some wild > >> programs utilizing this. > >> > >> But even btrfs-progs doesn't utilize them, the possibility are very > >> low. > > > > Obviously the ioctl was added so progs 'subvol sync' can use it for > > non-root users. I started working on it but there's a problem with the > > behaviour change between the user types. Root has full access and > > reports the progress while with this ioctl there were some problems I > > don't remember. The ioctl was designed to emulate all modes that root > > can do so it should be possible to get 1:1 output. > > Are you still planning to implement the full root-less subvolume wait in > progs? Yes, but I don't have an ETA. > Or is this feature deprecated and we can eventually remove it to reduce > LLM bug reports? I don't understand what would need to be deprecated, it's a new ioctl missing the userspace counterpart to implement an unprivileged functionality where it makes sense.