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Wong" Cc: linux-fsdevel@vger.kernel.org, Jeff Layton , Josef Bacik , Alexander Viro , Jan Kara , linux-kernel@vger.kernel.org, Hugh Dickins , linux-mm@kvack.org, Greg Kroah-Hartman , Tejun Heo , Eric Dumazet , Jakub Kicinski , Jann Horn , netdev@vger.kernel.org Subject: Re: [PATCH 09/14] xattr: move user limits for xattrs to generic infra Message-ID: <20260223-gewollt-tropenhelm-fbcdfb6b5a17@brauner> References: <20260216-work-xattr-socket-v1-0-c2efa4f74cb7@kernel.org> <20260216-work-xattr-socket-v1-9-c2efa4f74cb7@kernel.org> <20260221000326.GB11076@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260221000326.GB11076@frogsfrogsfrogs> X-Stat-Signature: 7w3dcseeaoigaqz586pujksdushct59b X-Rspamd-Server: rspam11 X-Rspam-User: X-Rspamd-Queue-Id: B282180016 X-HE-Tag: 1771848800-138484 X-HE-Meta: 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 Aj+iZCN6 3WYLSkQ2bdQezMlnSxEJPRzYs/JsW7flb8upZ3uaGZAM29oQ76v41nvdcMvjJI5WbeCrOZqhh9E0Ue9Ja2N0pIRV/eel7CB8LNFglnPn4gQYnyfPX/c/ub9QQFblc2zMg/PgmV5IDYXLeppdelQ9dCLQZT2BfLyHWdp7VhmdDwsOT9osB5ZBlsDhUEIzOA1ughcgi91slkSC8RNRMlkn9y38KQUd29Da/sm1r1bRa46bbXf7zJPlnqTn3MJJ0cMuk9eYvZ9FqUKSO3JMNChbajglkm2RWCx3M5LUg X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Feb 20, 2026 at 04:03:26PM -0800, Darrick J. Wong wrote: > On Mon, Feb 16, 2026 at 02:32:05PM +0100, Christian Brauner wrote: > > Signed-off-by: Christian Brauner > > --- > > fs/kernfs/inode.c | 75 ++------------------------------------------- > > fs/kernfs/kernfs-internal.h | 3 +- > > fs/xattr.c | 65 +++++++++++++++++++++++++++++++++++++++ > > include/linux/kernfs.h | 2 -- > > include/linux/xattr.h | 18 +++++++++++ > > 5 files changed, 87 insertions(+), 76 deletions(-) > > > > I know you're just moving code around and that looks ok, but: > > > diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h > > index b5a5f32fdfd1..d8f57f0af5e4 100644 > > --- a/include/linux/kernfs.h > > +++ b/include/linux/kernfs.h > > @@ -99,8 +99,6 @@ enum kernfs_node_type { > > > > #define KERNFS_TYPE_MASK 0x000f > > #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK > > -#define KERNFS_MAX_USER_XATTRS 128 > > -#define KERNFS_USER_XATTR_SIZE_LIMIT (128 << 10) > > I guess this means you can't have more than 128 xattrs total, and > sum(values) must be less than 128k? The fixed limit is a little odd, > but it's all pinned kernel memory, right? Yeah, it's all pinned kernel memory. > (IOWs, you haven't done anything wild ala xfile.c to make it possible to > swap that out to disk?) First time I've seen that. Very creative. But no, I've not done that. cgroupfs has been fine with a fixed limit for a long time no so for now it's fine to assume sockfs will be as well.