From patchwork Tue Oct 15 09:01:12 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Piotr Sarna X-Patchwork-Id: 11189897 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BE10717E6 for ; Tue, 15 Oct 2019 09:08:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A805620659 for ; Tue, 15 Oct 2019 09:08:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726939AbfJOJIE (ORCPT ); Tue, 15 Oct 2019 05:08:04 -0400 Received: from mx-out.tlen.pl ([193.222.135.142]:33571 "EHLO mx-out.tlen.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726405AbfJOJID (ORCPT ); Tue, 15 Oct 2019 05:08:03 -0400 X-Greylist: delayed 398 seconds by postgrey-1.27 at vger.kernel.org; Tue, 15 Oct 2019 05:08:02 EDT Received: (wp-smtpd smtp.tlen.pl 11047 invoked from network); 15 Oct 2019 11:01:22 +0200 Received: from unknown (HELO localhost.localdomain) (p.sarna@tlen.pl@[31.179.144.84]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP for ; 15 Oct 2019 11:01:22 +0200 From: Piotr Sarna To: linux-kernel@vger.kernel.org, mike.kravetz@oracle.com Cc: Piotr Sarna , linux-mm@kvack.org, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org Subject: [PATCH] hugetlbfs: add O_TMPFILE support Date: Tue, 15 Oct 2019 11:01:12 +0200 Message-Id: <22c29acf9c51dae17802e1b05c9e5e4051448c5c.1571129593.git.p.sarna@tlen.pl> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-WP-MailID: e93136fb553552c8e020d3da8703060d X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000000 [sUP0] Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org With hugetlbfs, a common pattern for mapping anonymous huge pages is to create a temporary file first. Currently libraries like libhugetlbfs and seastar create these with a standard mkstemp+unlink trick, but it would be more robust to be able to simply pass the O_TMPFILE flag to open(). O_TMPFILE is already supported by several file systems like ext4 and xfs. The implementation simply uses the existing d_tmpfile utility function to instantiate the dcache entry for the file. Tested manually by successfully creating a temporary file by opening it with (O_TMPFILE|O_RDWR) on mounted hugetlbfs and successfully mapping 2M huge pages with it. Without the patch, trying to open a file with O_TMPFILE results in -ENOSUP. Signed-off-by: Piotr Sarna Reviewed-by: Mike Kravetz --- fs/hugetlbfs/inode.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 1dcc57189382..277b7d231db8 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -815,8 +815,11 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, /* * File creation. Allocate an inode, and we're done.. */ -static int hugetlbfs_mknod(struct inode *dir, - struct dentry *dentry, umode_t mode, dev_t dev) +static int do_hugetlbfs_mknod(struct inode *dir, + struct dentry *dentry, + umode_t mode, + dev_t dev, + bool tmpfile) { struct inode *inode; int error = -ENOSPC; @@ -824,13 +827,22 @@ static int hugetlbfs_mknod(struct inode *dir, inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); if (inode) { dir->i_ctime = dir->i_mtime = current_time(dir); - d_instantiate(dentry, inode); + if (tmpfile) + d_tmpfile(dentry, inode); + else + d_instantiate(dentry, inode); dget(dentry); /* Extra count - pin the dentry in core */ error = 0; } return error; } +static int hugetlbfs_mknod(struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t dev) +{ + return do_hugetlbfs_mknod(dir, dentry, mode, dev, false); +} + static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); @@ -844,6 +856,12 @@ static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mo return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); } +static int hugetlbfs_tmpfile(struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true); +} + static int hugetlbfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { @@ -1102,6 +1120,7 @@ static const struct inode_operations hugetlbfs_dir_inode_operations = { .mknod = hugetlbfs_mknod, .rename = simple_rename, .setattr = hugetlbfs_setattr, + .tmpfile = hugetlbfs_tmpfile, }; static const struct inode_operations hugetlbfs_inode_operations = {