From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 536CDC433EF for ; Wed, 5 Jan 2022 13:23:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240314AbiAENXM (ORCPT ); Wed, 5 Jan 2022 08:23:12 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:40772 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240316AbiAENW5 (ORCPT ); Wed, 5 Jan 2022 08:22:57 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2F62FB81929; Wed, 5 Jan 2022 13:22:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2AABC36AE9; Wed, 5 Jan 2022 13:22:52 +0000 (UTC) Date: Wed, 5 Jan 2022 14:22:49 +0100 From: Christian Brauner To: Stefan Roesch Cc: io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-team@fb.com, torvalds@linux-foundation.org Subject: Re: [PATCH v11 2/4] fs: split off do_getxattr from getxattr Message-ID: <20220105132249.p3jwgshoe7lhpna3@wittgenstein> References: <20220104190936.3085647-1-shr@fb.com> <20220104190936.3085647-3-shr@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220104190936.3085647-3-shr@fb.com> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, Jan 04, 2022 at 11:09:34AM -0800, Stefan Roesch wrote: > This splits off do_getxattr function from the getxattr > function. This will allow io_uring to call it from its > io worker. > > Signed-off-by: Stefan Roesch > Acked-by: Christian Brauner > --- > fs/internal.h | 7 +++++++ > fs/xattr.c | 32 ++++++++++++++++++++------------ > 2 files changed, 27 insertions(+), 12 deletions(-) > > diff --git a/fs/internal.h b/fs/internal.h > index 00c98b0cd634..942b2005a2be 100644 > --- a/fs/internal.h > +++ b/fs/internal.h > @@ -220,6 +220,13 @@ struct xattr_ctx { > unsigned int flags; > }; > > + > +ssize_t do_getxattr(struct user_namespace *mnt_userns, > + struct dentry *d, > + const char *kname, > + void __user *value, > + size_t size); > + > int setxattr_copy(const char __user *name, struct xattr_ctx *ctx); > int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, > struct xattr_ctx *ctx); > diff --git a/fs/xattr.c b/fs/xattr.c > index dec7ac3e0e89..7f2b805ed56c 100644 > --- a/fs/xattr.c > +++ b/fs/xattr.c > @@ -675,19 +675,12 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, > /* > * Extended attribute GET operations > */ > -static ssize_t > -getxattr(struct user_namespace *mnt_userns, struct dentry *d, > - const char __user *name, void __user *value, size_t size) > +ssize_t > +do_getxattr(struct user_namespace *mnt_userns, struct dentry *d, > + const char *kname, void __user *value, size_t size) > { > - ssize_t error; > void *kvalue = NULL; > - char kname[XATTR_NAME_MAX + 1]; > - > - error = strncpy_from_user(kname, name, sizeof(kname)); > - if (error == 0 || error == sizeof(kname)) > - error = -ERANGE; > - if (error < 0) > - return error; > + ssize_t error; > > if (size) { > if (size > XATTR_SIZE_MAX) > @@ -711,10 +704,25 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d, > } > > kvfree(kvalue); > - > return error; > } > > +static ssize_t > +getxattr(struct user_namespace *mnt_userns, struct dentry *d, > + const char __user *name, void __user *value, size_t size) > +{ > + ssize_t error; > + struct xattr_name kname; > + > + error = strncpy_from_user(kname.name, name, sizeof(kname.name)); > + if (error == 0 || error == sizeof(kname.name)) > + error = -ERANGE; > + if (error < 0) > + return error; > + > + return do_getxattr(mnt_userns, d, kname.name, value, size); > +} Fwiw, this could have the same signature as do_setxattr(). So sm along the lines of (completely untested): Subject: [PATCH] UNTESTED --- fs/internal.h | 8 ++------ fs/xattr.c | 36 ++++++++++++++++++++++-------------- 2 files changed, 24 insertions(+), 20 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 942b2005a2be..d2332496724b 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -220,12 +220,8 @@ struct xattr_ctx { unsigned int flags; }; - -ssize_t do_getxattr(struct user_namespace *mnt_userns, - struct dentry *d, - const char *kname, - void __user *value, - size_t size); +ssize_t do_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx); int setxattr_copy(const char __user *name, struct xattr_ctx *ctx); int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, diff --git a/fs/xattr.c b/fs/xattr.c index 7f2b805ed56c..52bcfe149a9f 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -675,35 +675,34 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, /* * Extended attribute GET operations */ -ssize_t -do_getxattr(struct user_namespace *mnt_userns, struct dentry *d, - const char *kname, void __user *value, size_t size) +ssize_t do_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx) + { - void *kvalue = NULL; ssize_t error; + char *kname = ctx->kname.name; - if (size) { - if (size > XATTR_SIZE_MAX) - size = XATTR_SIZE_MAX; - kvalue = kvzalloc(size, GFP_KERNEL); - if (!kvalue) + if (ctx->size) { + if (ctx->size > XATTR_SIZE_MAX) + ctx->size = XATTR_SIZE_MAX; + ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL); + if (!ctx->kvalue) return -ENOMEM; } - error = vfs_getxattr(mnt_userns, d, kname, kvalue, size); + error = vfs_getxattr(mnt_userns, d, kname, ctx->kvalue, ctx->size); if (error > 0) { if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) posix_acl_fix_xattr_to_user(mnt_userns, kvalue, error); - if (size && copy_to_user(value, kvalue, error)) + if (ctx->size && copy_to_user(value, kvalue, error)) error = -EFAULT; - } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { + } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; } - kvfree(kvalue); return error; } @@ -713,6 +712,12 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d, { ssize_t error; struct xattr_name kname; + struct xattr_ctx ctx = { + .value = value, + .kvalue = NULL, + .size = size, + .kname = &kname, + }; error = strncpy_from_user(kname.name, name, sizeof(kname.name)); if (error == 0 || error == sizeof(kname.name)) @@ -720,7 +725,10 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d, if (error < 0) return error; - return do_getxattr(mnt_userns, d, kname.name, value, size); + error = do_getxattr(mnt_userns, d, &ctx); + + kvfree(ctx.kvalue); + return error; } static ssize_t path_getxattr(const char __user *pathname, -- 2.32.0