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Tue, 29 Sep 2026 15:35:06 +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 gN/3BKrau2oKKAAAD6G6ig (envelope-from ); Tue, 29 Sep 2026 15:35:06 +0000 From: Gabriel Krisman Bertazi To: Amir Goldstein Cc: linux-fsdevel@vger.kernel.org, Christian Brauner , Jan Kara , Theodore Ts'o , Hugh Dickins , Daniel Tang , linux-ext4@vger.kernel.org, Miklos Szeredi , linux-unionfs@vger.kernel.org, linux-mm@kvack.org, Chuck Lever , Pali =?utf-8?Q?Roh=C3=A1r?= Subject: Re: [PATCH 4/4] ovl: Expose the filesystem encoding through sysfs In-Reply-To: Organization: SUSE References: <20260928213155.2612039-1-krisman@suse.de> <20260928213155.2612039-5-krisman@suse.de> Date: Tue, 29 Sep 2026 11:35:04 -0400 Message-ID: <87mrt0xe8n.fsf@mailhost.krisman.be> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; URIBL_BLOCKED(0.00)[imap1.dmz-prg2.suse.org:helo,mailhost.krisman.be:mid,suse.de:email]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; ARC_NA(0.00)[]; HAS_ORG_HEADER(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; RCPT_COUNT_TWELVE(0.00)[13]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; FREEMAIL_CC(0.00)[vger.kernel.org,kernel.org,suse.cz,mit.edu,google.com,gmail.com,szeredi.hu,kvack.org]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; MISSING_XM_UA(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,imap1.dmz-prg2.suse.org:helo,mailhost.krisman.be:mid] X-Spam-Score: -2.80 X-Spam-Level: X-Spam-Flag: NO Amir Goldstein writes: > On Mon, Sep 28, 2026 at 11:32=E2=80=AFPM Gabriel Krisman Bertazi > wrote: > I am not ok with this API. > It is wrong in several ways. > It is not generic, we have already file_getattr() to get casefold status. > There was a suggestion by Pali [1] to get the supported xflags - statx st= yle, > which can be a way to say if a fs could return FS_XFLAG_CASEFOLD. > In Chuck's v2 [2] FILEATTR_CASEFOLD_TYPE was already suggested > as an extension to file_getattr(). I think we can still do that if we inc= lude > proper versioning in the casefold type. Ok. I'm not fond of the overlay part of this series at all, in particular due to the major:minor design. I was looking for an alternative way to do it and didn't find it, thus /sys/fs. > TBH, I don't think anyone requested this - you only mentioned > the need to know if tmpfs was mounted with casefold on and that > doesn't mean that etx4/ovl patches are justified, but ext4 can decide > for themselves. There is a need for a proper probing API when deciding to fallback to userspace casefolding workarounds, and that is not shmem specific at all. I'm sure the Wine folks that right now use ext4/overlayfs will also benefit from a smarter way to fetch the information. > The point is that this sysfs is not going to be the standard for all the > fs that can return the FS_XFLAG_CASEFOLD, so I see no reason > to add this sysfs interface to ovl. Ack. I'll drop patches 3 and 4 and wait on ext4 people to see if they want patch 2 to match f2fs. Will also keep an eye on FS_XFLAG_CASEFOLD. > Thanks, > Amir. > > [1] https://lore.kernel.org/linux-fsdevel/20250216164029.20673-4-pali@ker= nel.org/ > [2] https://lore.kernel.org/linux-fsdevel/20251211152116.480799-2-cel@ker= nel.org/ --=20 Gabriel Krisman Bertazi