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Wong" To: Christian Brauner 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: <20260221000326.GB11076@frogsfrogsfrogs> References: <20260216-work-xattr-socket-v1-0-c2efa4f74cb7@kernel.org> <20260216-work-xattr-socket-v1-9-c2efa4f74cb7@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260216-work-xattr-socket-v1-9-c2efa4f74cb7@kernel.org> X-Rspamd-Server: rspam09 X-Stat-Signature: zhpadmxuegwbm8apkqojns9gymirkx81 X-Rspamd-Queue-Id: 99246140003 X-Rspam-User: X-HE-Tag: 1771632208-497653 X-HE-Meta: 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 EpjfxRoE TUnerpvKXGX41oS+k+2okeHiZ4fb4sp1O5iLuSZIoOxPMv65CUcehz4bkQPxbaty/DmABM44baqZ6GTwGNAju0NMbjoCVqBbSnn3Zwb4UvTddsFuGIfny3CHEp2ld+slAFXGYPR/7J3mxsemTEHJ9613FMhHaw2SDBdV/Z2iBksITP8Pa13GXhGspnQ1Nu2Q5g8XwcCkHAqlpkMgkOr5voy787649L8BwmIWL3ZiaC0kTm5U= 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 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? (IOWs, you haven't done anything wild ala xfile.c to make it possible to swap that out to disk?) --D > > enum kernfs_node_flag { > KERNFS_ACTIVATED = 0x0010, > diff --git a/include/linux/xattr.h b/include/linux/xattr.h > index f60357d9f938..90a43a117127 100644 > --- a/include/linux/xattr.h > +++ b/include/linux/xattr.h > @@ -118,6 +118,20 @@ struct simple_xattr { > char value[]; > }; > > +#define SIMPLE_XATTR_MAX_NR 128 > +#define SIMPLE_XATTR_MAX_SIZE (128 << 10) > + > +struct simple_xattr_limits { > + atomic_t nr_xattrs; /* current user.* xattr count */ > + atomic_t xattr_size; /* current total user.* value bytes */ > +}; > + > +static inline void simple_xattr_limits_init(struct simple_xattr_limits *limits) > +{ > + atomic_set(&limits->nr_xattrs, 0); > + atomic_set(&limits->xattr_size, 0); > +} > + > int simple_xattrs_init(struct simple_xattrs *xattrs); > struct simple_xattrs *simple_xattrs_alloc(void); > struct simple_xattrs *simple_xattrs_lazy_alloc(struct simple_xattrs **xattrsp, > @@ -132,6 +146,10 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, > struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs, > const char *name, const void *value, > size_t size, int flags); > +int simple_xattr_set_limited(struct simple_xattrs *xattrs, > + struct simple_xattr_limits *limits, > + const char *name, const void *value, > + size_t size, int flags); > ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, > char *buffer, size_t size); > int simple_xattr_add(struct simple_xattrs *xattrs, > > -- > 2.47.3 > >