[LTP] [PATCH v3] move_mount03: check allow to mount beneath top mount
Petr Vorel
pvorel@suse.cz
Wed Mar 20 08:43:04 CET 2024
> Hi,
> some comments below.
> On 28. 12. 23 3:55, Wei Gao via ltp wrote:
> > Signed-off-by: Wei Gao <wegao@suse.com>
> > ---
> > include/lapi/fsmount.h | 4 +
> > runtest/syscalls | 1 +
> > .../kernel/syscalls/move_mount/.gitignore | 1 +
> > .../kernel/syscalls/move_mount/move_mount03.c | 128 ++++++++++++++++++
> > 4 files changed, 134 insertions(+)
> > create mode 100644 testcases/kernel/syscalls/move_mount/move_mount03.c
> > diff --git a/include/lapi/fsmount.h b/include/lapi/fsmount.h
> > index 07eb42ffa..216e966c7 100644
> > --- a/include/lapi/fsmount.h
> > +++ b/include/lapi/fsmount.h
> > @@ -115,6 +115,10 @@ static inline int mount_setattr(int dirfd, const char *from_pathname, unsigned i
> > }
> > #endif /* HAVE_MOUNT_SETATTR */
> > +#ifndef MOVE_MOUNT_BENEATH
> > +#define MOVE_MOUNT_BENEATH 0x00000200
> > +#endif /* MOVE_MOUNT_BENEATH */
> > +
> > /*
> > * New headers added in kernel after 5.2 release, create them for old userspace.
> > */
> > diff --git a/runtest/syscalls b/runtest/syscalls
> > index b1125dd75..04b758fd9 100644
> > --- a/runtest/syscalls
> > +++ b/runtest/syscalls
> > @@ -824,6 +824,7 @@ mount_setattr01 mount_setattr01
> > move_mount01 move_mount01
> > move_mount02 move_mount02
> > +move_mount03 move_mount03
> > move_pages01 move_pages01
> > move_pages02 move_pages02
> > diff --git a/testcases/kernel/syscalls/move_mount/.gitignore b/testcases/kernel/syscalls/move_mount/.gitignore
> > index 83ae40145..ddfe10128 100644
> > --- a/testcases/kernel/syscalls/move_mount/.gitignore
> > +++ b/testcases/kernel/syscalls/move_mount/.gitignore
> > @@ -1,2 +1,3 @@
> > /move_mount01
> > /move_mount02
> > +/move_mount03
> > diff --git a/testcases/kernel/syscalls/move_mount/move_mount03.c b/testcases/kernel/syscalls/move_mount/move_mount03.c
> > new file mode 100644
> > index 000000000..fff95c50b
> > --- /dev/null
> > +++ b/testcases/kernel/syscalls/move_mount/move_mount03.c
> > @@ -0,0 +1,128 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright (c) 2023 Christian Brauner <brauner@kernel.org>
> > + * Copyright (c) 2023 Wei Gao <wegao@suse.com>
> > + */
> > +
> > +/*\
> > + * [Description]
> > + *
> > + * Test allow to mount beneath top mount feature
> > + */
> > +
> > +/*
> > + * Test create for following commit:
> > + * commit 6ac392815628f317fcfdca1a39df00b9cc4ebc8b
> > + * Author: Christian Brauner <brauner@kernel.org>
> > + * Date: Wed May 3 13:18:42 2023 +0200
> > + * fs: allow to mount beneath top mount
> > + *
> > + * Above commit has heavily commented but i found following commit
> > + * contain simple summary of this feature for easy understanding:
> > + *
> > + * commit c0a572d9d32fe1e95672f24e860776dba0750a38
> > + * Author: Linus Torvalds <torvalds@linux-foundation.org>
> > + * TL;DR:
> > + *
> > + * > mount -t ext4 /dev/sda /mnt
> > + * |
> > + * --/mnt /dev/sda ext4
> > + *
> > + * > mount --beneath -t xfs /dev/sdb /mnt
> > + * |
> > + * --/mnt /dev/sdb xfs
> > + * --/mnt /dev/sda ext4
> > + *
> > + * > umount /mnt
> > + * |
> > + * --/mnt /dev/sdb xfs
> > + *
> > + * So base above scenario design following scenario for LTP check:
> > + *
> > + * > mount -t tmpfs /DIRA
> > + * |
> > + * --/DIRA(create A file within DIRA)
> > + *
> > + * > mount -t tmpfs /DIRB
> > + * |
> > + * --/DIRA(create B file within DIRB)
> > + *
> > + * > move_mount --beneath /DIRA /DIRB
> > + * |
> > + * --/mnt /DIRA /DIRB
> > + * --/mnt /DIRB
> > + *
> > + * If you check content of /DIRB, you can see file B
> > + *
> > + * > umount /DIRB
> > + * |
> > + * --/mnt /DIRA /DIRB
> > + * Check content of /DIRB, you can see file A exist since
> > + * current /DIRB mount source is already become /DIRA
> > + *
> > + * See also:
> > + * https://lwn.net/Articles/930591/
> > + * https://github.com/brauner/move-mount-beneath
> > + */
> > +
> > +#include <stdio.h>
> > +
> > +#include "tst_test.h"
> > +#include "lapi/fsmount.h"
> > +#include "lapi/sched.h"
> > +
> > +#define DIRA "LTP_DIR_A"
> > +#define DIRB "LTP_DIR_B"
> > +
> > +static void run(void)
> > +{
> > + int fda, fdb;
> > +
> > + SAFE_MOUNT("none", DIRA, "tmpfs", 0, 0);
> > + SAFE_MOUNT("none", DIRB, "tmpfs", 0, 0);
> > + SAFE_TOUCH(DIRA "/A", 0, NULL);
> > + SAFE_TOUCH(DIRB "/B", 0, NULL);
> > +
> > + /* TEST(fda = open_tree(AT_FDCWD, DIRA, OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE)); */
> Is the comment needed?
+1
> > + fda = open_tree(AT_FDCWD, DIRA, OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE);
> > + if (fda == -1)
> > + tst_brk(TBROK | TERRNO, "open_tree() failed");
> > +
> > + fdb = SAFE_OPEN(DIRB, O_PATH | O_NOFOLLOW, 0666);
> > + TST_EXP_PASS(move_mount(fda, "", fdb, "",
> > + MOVE_MOUNT_BENEATH | MOVE_MOUNT_F_EMPTY_PATH |
> > + MOVE_MOUNT_T_EMPTY_PATH));
> > + SAFE_CLOSE(fda);
> > + SAFE_CLOSE(fdb);
> > +
> > + TST_EXP_PASS(access(DIRB "/B", F_OK));
> It'd also make sense the check here that file A still exists in DIRA but not
> in DIRB.
> > + SAFE_UMOUNT(DIRB);
> > + TST_EXP_PASS(access(DIRB "/A", F_OK));
> > +
> > + SAFE_UMOUNT(DIRB);
> > + SAFE_UMOUNT(DIRA);
> > +}
> > +
> > +static void setup(void)
> > +{
> > + SAFE_MKDIR(DIRA, 0777);
> > + SAFE_MKDIR(DIRB, 0777);
> > +}
> > +
> > +static void cleanup(void)
> > +{
> > + if (tst_is_mounted_at_tmpdir(DIRA))
> > + SAFE_UMOUNT(DIRA);
> > +
> > + if (tst_is_mounted_at_tmpdir(DIRB))
> > + SAFE_UMOUNT(DIRB);
> I believe that DIRB may need to be unmounted twice here. Also please close
> fda and fdb here if they're still open.
What would do the second mount? move_mount() ?
There are SAFE_UMOUNT() in the end of the testing function, that's why usually
even these 2 SAFE_UMOUNT() aren't needed (but obviously we need to add them if
SAFE_TOUCH() or something quits testing early):
move_mount03.c:92: TPASS: move_mount(fda, "", fdb, "", MOVE_MOUNT_BENEATH | MOVE_MOUNT_F_EMPTY_PATH | MOVE_MOUNT_T_EMPTY_PATH) passed
move_mount03.c:98: TPASS: access(DIRB "/B", F_OK) passed
move_mount03.c:99: TINFO: Umounting /tmp/LTP_movqeTZGu/LTP_DIR_B
move_mount03.c:100: TPASS: access(DIRB "/A", F_OK) passed
move_mount03.c:102: TINFO: Umounting /tmp/LTP_movqeTZGu/LTP_DIR_B
move_mount03.c:103: TINFO: Umounting /tmp/LTP_movqeTZGu/LTP_DIR_A
tst_device.c:442: TINFO: No device is mounted at /tmp/LTP_movqeTZGu/LTP_DIR_A
tst_device.c:442: TINFO: No device is mounted at /tmp/LTP_movqeTZGu/LTP_DIR_B
Kind regards,
Petr
> > +}
> > +
> > +static struct tst_test test = {
> > + .test_all = run,
> > + .needs_root = 1,
> > + .min_kver = "6.5.0",
> > + .needs_tmpdir = 1,
> > + .setup = setup,
> > + .cleanup = cleanup,
> > +};
More information about the ltp
mailing list