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b=V5U8pIq9CYVjKN1M26c9b9NKyxbKNnsst43BpYHw1DsITUIVizoffTmheov44CS5q RC4YKVuVcJV1HeIny7fKMAPNUaVudn/uTOVvE44fxeitC4tGQLrVW5VFS7IbGno+H+ cT2aATaZRzZsglm4rt0Y9AF1jrW8fI5GyXvQw0rIyoOyDQW+I92HQ7KEz4K8PpOoiP 83HyHOFnC80JpiUmO6zQ2C4JY4DUjKUow0IeN7OzXJfPEspGNm+1XkSkX6RsNMyFZx hWGUUq+V+NminNRePBFveQW0fsFFOrqS7G+6Qjvo70M6y6660opAlN7QRmJHAlwatb Ezhvlm7T0Nwlg== Date: Fri, 22 May 2026 04:02:05 +0000 From: Jaegeuk Kim To: Eric Biggers Cc: Theodore Tso , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Akilesh Kailash , Christian Brauner Subject: Re: [f2fs-dev] [PATCH v2] f2fs: another way to set large folio by remembering inode number Message-ID: References: <20260409134538.3692605-1-jaegeuk@kernel.org> <20260521155748.GA79343@macsyma-wired.lan> <20260522035331.GE5937@quark> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260522035331.GE5937@quark> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: E6BD88000D X-Stat-Signature: 4hnr4jsxpe78a9czr5igtszaj4nai47w X-Rspam-User: X-HE-Tag: 1779422527-651111 X-HE-Meta: U2FsdGVkX1/PDrd7AfqZSihJgktAFEgBUDyWIB4dSM2i8/4fXIH/dDrxJ+T2WHdTdNi0B2coHiNf+KHXv2cxo8Q3FpeZkXyjk7JEb1Ze5BV6Ne1RWx31sLs2NzXzKv1vonzxkHwQ0hqbd3oIZ5RSb7LXkc7afY2OliZ3IJXuTpteBYeWZyRH+e+wJ+CKXWhgeWjxZdM8YzrNqQ78S2rKv0EvGXUyK8uUwxexYjz59vfpHoAqg2orax2qFypQhFZVif8T/O85k1f6gNcpy5bDJorWzQs+rp2usqY5I/GPkBZRllI0FJ1Cav9xEBjUnQZe85UU1kZ/5VZ9eFFQwLvAooCY6xvSTxbNFoIZvqVyHa+OHFxd8RRp5IWogIm0Q1gdl52v1v2gusciK8DjU70QenLThq8HHnkoyMPF1u3HJgc3TBCFfJsYPF75g4kgvqOYv5m1OjbmdfxAbhH0OoSBr30gVqpzYl8aYGglYLvJwITEv9HNJvyS9iySSMX/O6UR2Af+8RCQd6dq6FB0QGj1PvvnMmJ/PbIZO6qjIIc+R2jpiOZhZjEznsesTrbz79zTs3yfyCUUC3vUH/MAaJpMOR8GyhxqVU5U6jZm6l88V3itcryKN5abiO/hrPIUWualhylS2wfMw+8X2nixnhwGoXrJXOKzhxJN71HYd2Db3iasorw8kQC1Mee7dBCmY872l+uq/QZ2+MIkZScrBljzHmsVEVujqEuQOwJPeck5/XxUC7vxQJumx0Yi9OgKsILpUUxDdQdv7jgVbhpFuJ2EeotdiKqzo8wnMvq0pNlm71/IKT2DRfgvAfIUTPAsT4Q8ayy06CEB1HGUZrYUgkePZDjrewDCAZFED9WqwyWMy1zVW7uWPU5gHQnPUKqV2PA00mZcuXVc5mgcurmaXaW+DNl8yjVFQLAmOwqtw4PShew//lSSnYMHOt2iCv5uoruolDXwNmt8sbIEVhXVZJ+ yiHNfYz/ 0zKxBS6yQeKFuiJYEFbN3yjWxYTI33a5bZRHEx5uPC3INrRWMLED+vsuMcaXgkqkBUOQ6AFM88/zTVObjhjbm2VS9YuiZNzzy199dkXHJKPZ1GkPkdcmrx6nBUhJ79kgoCDyUJViPDiYH6faX4stl7KbXCpoZLuvGdHe08BxkQ/9Wtbi9msnIzVoBqCx2MACJvLtP/TvbhSj5DxILSXeZjR8U+GLzxRaMLMzeFfNILq5ltjN8/8Y/q66EfOoFqxmdYMvOi1Vphx687lE8DV6XwdbVI97ipUHz4B4K4bNwHbdNHCqHKkYANEqIAA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 05/21, Eric Biggers via Linux-f2fs-devel wrote: > On Fri, May 22, 2026 at 03:32:39AM +0000, Jaegeuk Kim wrote: > > On 05/21, Theodore Tso wrote: > > > On Thu, May 21, 2026 at 01:51:08AM -0700, Christoph Hellwig wrote: > > > > > You haven't sent a proposal. This is a reply to a reply to a reply of a > > > > > patch. There's no justification for why f2fs is so special that it > > > > > needs this. What the hell is going on? You know this is not the way to > > > > > get code merged into Linux. > > > > > > > > None of this got properly answers, and this broken interface now landed > > > > in linux-next. IT is offloading a user.* xattr which is free-form > > > > user data with semantics that are weird to say it very nicely. > > > > > > > > All this was done against the advice in the mailing list discussion. > > > > > > So let me get this straight. This is a magic xattr interface which is > > > not even persisted in the file system, but instead sets a 32-bit > > > bitmask in the struct inode which disappears once the inode gets > > > flushed from the inode stack. And it uses a generic xattr name, > > > "user.fadvise". > > > > > > There's no way in *hell* any other file system is likely to adopt such > > > a broken interface, so why didn't you just use an ioctl to set this > > > magic f2fs-specific flag? > > > > I went this route because Android heavily restricts ioctl() permissions > > and we needed broader access for this to work within the framework. > > It's straightforward (2 lines I think) to update Android's SELinux > policy to allow an ioctl in all domains. So that doesn't seem like a > reason to not use an ioctl. In fact this is actually a reason *to* use > an ioctl, as it shows that ioctls can be allowed/denied independently as > needed, whereas xattrs just use the file write permission. Ok, that's also great news to me. > > - Eric > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel