Linux-api Archive on lore.kernel.org
 help / color / Atom feed
From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org
Subject: [PATCH 02/23] fs: refactor ksys_umount
Date: Tue, 28 Jul 2020 18:33:55 +0200
Message-ID: <20200728163416.556521-3-hch@lst.de> (raw)
In-Reply-To: <20200728163416.556521-1-hch@lst.de>

Factor out a path_umount helper that takes a struct path * instead of the
actual file name.  This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/namespace.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 6f8234f74bed90..43834b59eff6c3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1706,36 +1706,19 @@ static inline bool may_mandlock(void)
 }
 #endif
 
-/*
- * Now umount can handle mount points as well as block devices.
- * This is important for filesystems which use unnamed block devices.
- *
- * We now support a flag for forced unmount like the other 'big iron'
- * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
- */
-
-int ksys_umount(char __user *name, int flags)
+static int path_umount(struct path *path, int flags)
 {
-	struct path path;
 	struct mount *mnt;
 	int retval;
-	int lookup_flags = LOOKUP_MOUNTPOINT;
 
 	if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
 		return -EINVAL;
-
 	if (!may_mount())
 		return -EPERM;
 
-	if (!(flags & UMOUNT_NOFOLLOW))
-		lookup_flags |= LOOKUP_FOLLOW;
-
-	retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);
-	if (retval)
-		goto out;
-	mnt = real_mount(path.mnt);
+	mnt = real_mount(path->mnt);
 	retval = -EINVAL;
-	if (path.dentry != path.mnt->mnt_root)
+	if (path->dentry != path->mnt->mnt_root)
 		goto dput_and_out;
 	if (!check_mnt(mnt))
 		goto dput_and_out;
@@ -1748,12 +1731,25 @@ int ksys_umount(char __user *name, int flags)
 	retval = do_umount(mnt, flags);
 dput_and_out:
 	/* we mustn't call path_put() as that would clear mnt_expiry_mark */
-	dput(path.dentry);
+	dput(path->dentry);
 	mntput_no_expire(mnt);
-out:
 	return retval;
 }
 
+int ksys_umount(char __user *name, int flags)
+{
+	int lookup_flags = LOOKUP_MOUNTPOINT;
+	struct path path;
+	int ret;
+
+	if (!(flags & UMOUNT_NOFOLLOW))
+		lookup_flags |= LOOKUP_FOLLOW;
+	ret = user_path_at(AT_FDCWD, name, lookup_flags, &path);
+	if (ret)
+		return ret;
+	return path_umount(&path, flags);
+}
+
 SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
 {
 	return ksys_umount(name, flags);
-- 
2.27.0


  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-28 16:33 add file system helpers that take kernel pointers for the init code v4 Christoph Hellwig
2020-07-28 16:33 ` [PATCH 01/23] fs: refactor do_mount Christoph Hellwig
2020-07-28 16:33 ` Christoph Hellwig [this message]
2020-08-06 14:44   ` [PATCH 02/23] fs: refactor ksys_umount Naresh Kamboju
2020-08-17 13:44     ` Naresh Kamboju
2020-07-28 16:33 ` [PATCH 03/23] fs: push the getname from do_rmdir into the callers Christoph Hellwig
2020-07-28 16:33 ` [PATCH 04/23] devtmpfs: refactor devtmpfsd() Christoph Hellwig
2020-07-28 16:59   ` Greg Kroah-Hartman
2020-07-28 16:33 ` [PATCH 05/23] init: initialize ramdisk_execute_command at compile time Christoph Hellwig
2020-07-28 16:33 ` [PATCH 06/23] init: mark console_on_rootfs as __init Christoph Hellwig
2020-07-28 16:34 ` [PATCH 07/23] init: mark create_dev " Christoph Hellwig
2020-07-28 16:34 ` [PATCH 08/23] init: add an init_mount helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 09/23] init: add an init_umount helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 10/23] init: add an init_unlink helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 11/23] init: add an init_rmdir helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 12/23] init: add an init_chdir helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 13/23] init: add an init_chroot helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 14/23] init: add an init_chown helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 15/23] init: add an init_chmod helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 16/23] init: add an init_eaccess helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 17/23] init: add an init_link helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 18/23] init: add an init_symlink helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 19/23] init: add an init_mkdir helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 20/23] init: add an init_mknod helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 21/23] init: add an init_stat helper Christoph Hellwig
2020-09-04 13:53   ` [PATCH] init: fix error check in clean_path() Barret Rhoden
2020-09-04 16:04     ` Christoph Hellwig
2020-07-28 16:34 ` [PATCH 22/23] init: add an init_utimes helper Christoph Hellwig
2020-07-28 16:34 ` [PATCH 23/23] init: add an init_dup helper Christoph Hellwig
2020-07-29 19:51 ` add file system helpers that take kernel pointers for the init code v4 Al Viro
2020-07-30  6:25   ` Christoph Hellwig
2020-07-31  2:14     ` Al Viro
2020-07-31  6:33       ` Christoph Hellwig
2020-08-03 14:56 ` Qian Cai
2020-08-03 15:08   ` Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200728163416.556521-3-hch@lst.de \
    --to=hch@lst.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-raid@vger.kernel.org \
    --cc=rafael@kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-api Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-api/0 linux-api/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-api linux-api/ https://lore.kernel.org/linux-api \
		linux-api@vger.kernel.org
	public-inbox-index linux-api

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-api


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git