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Mon, 25 May 2026 10:28:20 +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 UXmoOkQkFGqLRQAAD6G6ig (envelope-from ); Mon, 25 May 2026 10:28:20 +0000 Date: Mon, 25 May 2026 12:28:04 +0200 From: David Sterba To: Matthew Wilcox Cc: Chris Mason , David Sterba , linux-btrfs@vger.kernel.org, Qu Wenruo , Boris Burkov , Filipe Manana , Sweet Tea Dorminy Subject: Re: [PATCH 0/3] Three folio-related btrfs fixes Message-ID: <20260525102804.GW12792@suse.cz> Reply-To: dsterba@suse.cz References: <20260522181411.2487732-1-willy@infradead.org> <20260522223855.GA29010@twin.jikos.cz> <20260523140601.GA183694@suse.cz> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) X-Spam-Score: -4.00 X-Spamd-Result: default: False [-4.00 / 50.00]; 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)[-0.995]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_SEVEN(0.00)[8]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; REPLYTO_ADDR_EQ_FROM(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.cz:replyto,suse.cz:mid]; RCVD_COUNT_TWO(0.00)[2]; REPLYTO_DOM_NEQ_TO_DOM(0.00)[] X-Spam-Level: X-Spam-Flag: NO On Sun, May 24, 2026 at 09:05:37PM +0100, Matthew Wilcox wrote: > On Sat, May 23, 2026 at 04:06:01PM +0200, David Sterba wrote: > > On Sat, May 23, 2026 at 12:56:29AM +0100, Matthew Wilcox wrote: > > > On Sat, May 23, 2026 at 12:38:55AM +0200, David Sterba wrote: > > > > On Fri, May 22, 2026 at 07:14:06PM +0100, Matthew Wilcox (Oracle) wrote: > > > > > All of these were discovered through auditing the (mis)uses of the folio > > > > > API throughout the kernel; I haven't been specifically reviewing btrfs, > > > > > nor testing. > > > > > > > > > > Matthew Wilcox (Oracle) (3): > > > > > Revert "btrfs: fix the file offset calculation inside > > > > > btrfs_decompress_buf2page()" > > > > > > > > Why do you do the revert? It does not seem suitable for this case, we > > > > use reverts if we want to get back to the original behaviour, or when > > > > removing a patch from a long series to avoid a rebase. Merging the first > > > > and second patch makes more sense to me. > > > > > > The revert is for a patch which was merged into v6.16. Since the fix > > > for page_offset() was merged into v6.15, af566bdaff54 should never have > > > been merged, and it can safely be reverted. > > > > That it can be safely/cleanly reverted does not matter, you could say > > that about many other patches. If the code was wrong then fix it in a > > "forward" manner, no need for revert, namely for code from a year ago. > > The patch should never have been merged. It didn't make sense at > the time. Reverting it is the right approach. There is no "forward" > to move it to, other than converting the code to use folios instead of > pages, which I'm not signing up for right now as that's more involved. I've read the patches again and you're right. The part I overlooked was that 2nd and 3rd didn't change the same code, so it's reverting to the previous state (without a followup). > The fact that it's been in for a year with nobody reporting the bug just > shows the lack of 32-bit testing (and users). Yeah, we don't have 32bit setups for testing and distros have been gradually removing their 32bit versions and I don't remember any recent report. In the past it's been mostly from 3rd party testing, not users.