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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 894F4C433EF for ; Thu, 30 Jun 2022 21:34:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F2C128E0002; Thu, 30 Jun 2022 17:34:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EDC5F8E0001; Thu, 30 Jun 2022 17:34:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DA5058E0002; Thu, 30 Jun 2022 17:34:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CC8288E0001 for ; Thu, 30 Jun 2022 17:34:38 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 9A63B34220 for ; Thu, 30 Jun 2022 21:34:38 +0000 (UTC) X-FDA: 79636206636.13.DB76E24 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf24.hostedemail.com (Postfix) with ESMTP id 069D1180037 for ; Thu, 30 Jun 2022 21:34:37 +0000 (UTC) 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 C60F9B82D61; Thu, 30 Jun 2022 21:34:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67FEAC34115; Thu, 30 Jun 2022 21:34:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656624874; bh=QUYChKIH5jkJFejFJhzaJZW9GlRUXUy7m5NnF5YR/lg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QwitmLFyVG60TsbdfkulminJEZ5nwrrVqfhExwyOd1V/eLDLP47GZgDwPDeM+/ecX eNLwcJOjpCL69OuFrCkZqHOt2OeRonCXj6FXZNjcP9Ul1sbHMZ5XC9ZVXz21HyFpl2 q0K/kQiTaCtKMJ7ET3Ig85OfB55/wiwm/wXtCOl8ZJuGxVu5RKyZ+Yjj5HOfCJ012t PA8x9pKw9HK6MD9BrAGD5eQKHY6qQspVCA+jZl1/p5TX+pROVwKdzavdOJ4tlICE1R I8kIVcE9EITqs6NBdLwO59vF2OEtGHmkb7B+dWSFzu++FPZrLKUZC2H2P8CgXxSR6v aIv/cqvlbR93Q== Date: Thu, 30 Jun 2022 14:34:33 -0700 From: "Darrick J. Wong" To: Khalid Aziz Cc: akpm@linux-foundation.org, willy@infradead.org, aneesh.kumar@linux.ibm.com, arnd@arndb.de, 21cnbao@gmail.com, corbet@lwn.net, dave.hansen@linux.intel.com, david@redhat.com, ebiederm@xmission.com, hagen@jauu.net, jack@suse.cz, keescook@chromium.org, kirill@shutemov.name, kucharsk@gmail.com, linkinjeon@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, longpeng2@huawei.com, luto@kernel.org, markhemm@googlemail.com, pcc@google.com, rppt@kernel.org, sieberf@amazon.com, sjpark@amazon.de, surenb@google.com, tst@schoebel-theuer.de, yzaikin@google.com Subject: Re: [PATCH v2 3/9] mm/mshare: make msharefs writable and support directories Message-ID: References: <397ad80630444b90877625a1e94dd81392fc678e.1656531090.git.khalid.aziz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <397ad80630444b90877625a1e94dd81392fc678e.1656531090.git.khalid.aziz@oracle.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656624878; a=rsa-sha256; cv=none; b=gu5msY9K/qKThKvaWW/HCPDJqZ0TSrHK9XWgQupO09tbSy5UTxxeMRXrVit75yl4GovnlW WCY7DgLiWFNSB9rxeFXGOdhIeNVJANb8yFJ44lliHuBmWd6mL7LSnnuAM8Bs2y5d0hD7qA EzzuVyN7QI/bxiOWxUZoWc53wLqiZqE= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=QwitmLFy; spf=pass (imf24.hostedemail.com: domain of djwong@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=djwong@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656624878; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=EGvrLF5M+CYNWGSJZgZ1ox45fNbn0oHRp7PLi5nINAk=; b=V8YiZXKfcDCFn7Or1TljC0DQr3oQKRgEhwAJLtxKifvpqpmC+eOARccXfN5l9wPC+In94F kuFY+k/OjNrdGX2N7jFEObYK6vmIw/BYMRfQaho/KTnJUloDfaAD/HUsx/wTHy+S8MPyCm L06cqBfVdlfe/gMNFctmqB0bTLptk7k= X-Rspam-User: X-Rspamd-Server: rspam04 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=QwitmLFy; spf=pass (imf24.hostedemail.com: domain of djwong@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=djwong@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Stat-Signature: zuys83dppmoarfrs1jmr1cuz3air3bx8 X-Rspamd-Queue-Id: 069D1180037 X-HE-Tag: 1656624877-724736 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: On Wed, Jun 29, 2022 at 04:53:54PM -0600, Khalid Aziz wrote: > Make msharefs filesystem writable and allow creating directories > to support better access control to mshare'd regions defined in > msharefs. > > Signed-off-by: Khalid Aziz > --- > mm/mshare.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 186 insertions(+), 9 deletions(-) > > diff --git a/mm/mshare.c b/mm/mshare.c > index 3e448e11c742..2d5924d39221 100644 > --- a/mm/mshare.c > +++ b/mm/mshare.c > @@ -21,11 +21,21 @@ > #include > #include > #include > +#include > > static struct super_block *msharefs_sb; > > +static const struct inode_operations msharefs_dir_inode_ops; > +static const struct inode_operations msharefs_file_inode_ops; > + > +static int > +msharefs_open(struct inode *inode, struct file *file) > +{ > + return simple_open(inode, file); > +} > + > static const struct file_operations msharefs_file_operations = { > - .open = simple_open, > + .open = msharefs_open, > .llseek = no_llseek, > }; > > @@ -42,6 +52,113 @@ msharefs_d_hash(const struct dentry *dentry, struct qstr *qstr) > return 0; > } > > +static struct dentry > +*msharefs_alloc_dentry(struct dentry *parent, const char *name) > +{ > + struct dentry *d; > + struct qstr q; > + int err; > + > + q.name = name; > + q.len = strlen(name); > + > + err = msharefs_d_hash(parent, &q); > + if (err) > + return ERR_PTR(err); > + > + d = d_alloc(parent, &q); > + if (d) > + return d; > + > + return ERR_PTR(-ENOMEM); > +} > + > +static struct inode > +*msharefs_get_inode(struct super_block *sb, const struct inode *dir, > + umode_t mode) > +{ > + struct inode *inode = new_inode(sb); > + > + if (inode) { Not sure why you wouldn't go with the less-indently version: if (!inode) return ERR_PTR(-ENOMEM); inode->i_ino = get_next_ino(); > + inode->i_ino = get_next_ino(); > + inode_init_owner(&init_user_ns, inode, dir, mode); > + > + inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); > + > + switch (mode & S_IFMT) { Shouldn't we set the mode somewhere? > + case S_IFREG: > + inode->i_op = &msharefs_file_inode_ops; > + inode->i_fop = &msharefs_file_operations; > + break; > + case S_IFDIR: > + inode->i_op = &msharefs_dir_inode_ops; > + inode->i_fop = &simple_dir_operations; > + inc_nlink(inode); > + break; > + case S_IFLNK: > + inode->i_op = &page_symlink_inode_operations; > + break; > + default: > + discard_new_inode(inode); > + inode = NULL; > + break; > + } > + } > + > + return inode; > +} > + > +static int > +msharefs_mknod(struct user_namespace *mnt_userns, struct inode *dir, > + struct dentry *dentry, umode_t mode, dev_t dev) > +{ > + struct inode *inode; > + int err = 0; > + > + inode = msharefs_get_inode(dir->i_sb, dir, mode); > + if (IS_ERR(inode)) > + return PTR_ERR(inode); ...and if @inode is NULL? > + > + d_instantiate(dentry, inode); > + dget(dentry); > + dir->i_mtime = dir->i_ctime = current_time(dir); > + > + return err; > +} > + > +static int > +msharefs_create(struct user_namespace *mnt_userns, struct inode *dir, > + struct dentry *dentry, umode_t mode, bool excl) > +{ > + return msharefs_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0); > +} > + > +static int > +msharefs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, > + struct dentry *dentry, umode_t mode) > +{ > + int ret = msharefs_mknod(&init_user_ns, dir, dentry, mode | S_IFDIR, 0); > + > + if (!ret) > + inc_nlink(dir); > + return ret; > +} > + > +static const struct inode_operations msharefs_file_inode_ops = { > + .setattr = simple_setattr, > + .getattr = simple_getattr, > +}; > +static const struct inode_operations msharefs_dir_inode_ops = { > + .create = msharefs_create, > + .lookup = simple_lookup, > + .link = simple_link, > + .unlink = simple_unlink, > + .mkdir = msharefs_mkdir, > + .rmdir = simple_rmdir, > + .mknod = msharefs_mknod, > + .rename = simple_rename, > +}; > + > static void > mshare_evict_inode(struct inode *inode) > { > @@ -58,7 +175,7 @@ mshare_info_read(struct file *file, char __user *buf, size_t nbytes, > { > char s[80]; > > - sprintf(s, "%ld", PGDIR_SIZE); > + sprintf(s, "%ld\n", PGDIR_SIZE); Changing this already? > return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); > } > > @@ -72,6 +189,38 @@ static const struct super_operations mshare_s_ops = { > .evict_inode = mshare_evict_inode, > }; > > +static int > +prepopulate_files(struct super_block *s, struct inode *dir, > + struct dentry *root, const struct tree_descr *files) > +{ > + int i; > + struct inode *inode; > + struct dentry *dentry; > + > + for (i = 0; !files->name || files->name[0]; i++, files++) { > + if (!files->name) > + continue; What ends the array? NULL name or empty name? Do we have to erase all of these when the fs gets unmounted? --D > + > + dentry = msharefs_alloc_dentry(root, files->name); > + if (!dentry) > + return -ENOMEM; > + > + inode = msharefs_get_inode(s, dir, S_IFREG | files->mode); > + if (!inode) { > + dput(dentry); > + return -ENOMEM; > + } > + inode->i_mode = S_IFREG | files->mode; > + inode->i_atime = inode->i_mtime = inode->i_ctime > + = current_time(inode); > + inode->i_fop = files->ops; > + inode->i_ino = i; > + d_add(dentry, inode); > + } > + > + return 0; > +} > + > static int > msharefs_fill_super(struct super_block *sb, struct fs_context *fc) > { > @@ -79,21 +228,49 @@ msharefs_fill_super(struct super_block *sb, struct fs_context *fc) > [2] = { "mshare_info", &mshare_info_ops, 0444}, > {""}, > }; > - int err; > + struct inode *inode; > + struct dentry *root; > + int err = 0; > > - err = simple_fill_super(sb, MSHARE_MAGIC, mshare_files); > - if (!err) { > - msharefs_sb = sb; > - sb->s_d_op = &msharefs_d_ops; > - sb->s_op = &mshare_s_ops; > + sb->s_blocksize = PAGE_SIZE; > + sb->s_blocksize_bits = PAGE_SHIFT; > + sb->s_magic = MSHARE_MAGIC; > + sb->s_op = &mshare_s_ops; > + sb->s_d_op = &msharefs_d_ops; > + sb->s_time_gran = 1; > + > + inode = msharefs_get_inode(sb, NULL, S_IFDIR | 0777); > + if (!inode) { > + err = -ENOMEM; > + goto out; > } > + inode->i_ino = 1; > + root = d_make_root(inode); > + if (!root) { > + err = -ENOMEM; > + goto out; > + } > + > + err = prepopulate_files(sb, inode, root, mshare_files); > + if (err < 0) > + goto clean_root; > + > + sb->s_root = root; > + msharefs_sb = sb; > + return err; > + > +clean_root: > + d_genocide(root); > + shrink_dcache_parent(root); > + dput(root); > +out: > return err; > } > > static int > msharefs_get_tree(struct fs_context *fc) > { > - return get_tree_single(fc, msharefs_fill_super); > + return get_tree_nodev(fc, msharefs_fill_super); > } > > static const struct fs_context_operations msharefs_context_ops = { > -- > 2.32.0 >