[LTP] [PATCH v2 0/2] open_tree_attr syscall coverage

[LTP] [PATCH v2 0/2] open_tree_attr syscall coverage

[Andrea Cervesato]

open_tree_attr has been added in kernel 6.15 in the following commit:
https://lore.kernel.org/all/20250128-work-mnt_idmap-update-v2-v1-3-c25feb0d2eb3@kernel.org/

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
Changes in v2:
- close FD after opening it with open_tree()
- revert style edit in setup()
- use TST_EXP_FD_SILENT()
- Link to v1: https://lore.kernel.org/r/20250828-open_tree_attr-v1-0-f339a0e51e22@suse.com

---
Andrea Cervesato (2):
      Add open_tree_attr fallback
      mount_setattr01: add open_tree_attr variant

 configure.ac                                       |  1 +
 include/lapi/fsmount.h                             |  8 +++
 .../syscalls/mount_setattr/mount_setattr01.c       | 68 ++++++++++++++++------
 3 files changed, 60 insertions(+), 17 deletions(-)
---
base-commit: 9691c4b2bea4f772d61ca9e9a93d2087c88f6040
change-id: 20250828-open_tree_attr-4b2ece576c1c

Best regards,
-- 
Andrea Cervesato <andrea.cervesato@suse.com>


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[LTP] [PATCH v2 1/2] Add open_tree_attr fallback

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

open_tree_attr syscall has been introduced in kernel 6.15 and it's
now defined in lapi/fsmount.h.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 configure.ac           | 1 +
 include/lapi/fsmount.h | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/configure.ac b/configure.ac
index 62ae27d494474fe342b1cceeac7f4c21c0b1028c..2d4d527bcaa675dae5d712a96d266d17184b8a0d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -137,6 +137,7 @@ AC_CHECK_FUNCS_ONCE([ \
     move_mount \
     name_to_handle_at \
     open_tree \
+    open_tree_attr \
     openat \
     openat2 \
     pidfd_getfd \
diff --git a/include/lapi/fsmount.h b/include/lapi/fsmount.h
index 1783272a00a1a049031cacbb417239123450a0e4..451987ae637d040e08970b7ffcf015bae07a6f11 100644
--- a/include/lapi/fsmount.h
+++ b/include/lapi/fsmount.h
@@ -105,6 +105,14 @@ static inline int open_tree(int dirfd, const char *pathname, unsigned int flags)
 }
 #endif /* HAVE_OPEN_TREE */
 
+#ifndef HAVE_OPEN_TREE_ATTR
+static inline int open_tree_attr(int dirfd, const char *pathname, unsigned int flags,
+				 struct mount_attr *attr, size_t size)
+{
+	return tst_syscall(__NR_open_tree_attr, dirfd, pathname, flags, attr, size);
+}
+#endif /* HAVE_OPEN_TREE_ATTR */
+
 #ifndef HAVE_MOUNT_SETATTR
 static inline int mount_setattr(int dirfd, const char *from_pathname, unsigned int flags,
 				struct mount_attr *attr, size_t size)

-- 
2.51.0


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[LTP] [PATCH v2 2/2] mount_setattr01: add open_tree_attr variant

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

This patch simply introduces a new variant to the mount_setattr01
test, in order to verify that open_tree_attr() works correctly.
The open_tree_attr() syscall has been introduced in the kernel v6.15 by
commit "c4a16820d901 - fs: add open_tree_attr()".

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 .../syscalls/mount_setattr/mount_setattr01.c       | 68 ++++++++++++++++------
 1 file changed, 51 insertions(+), 17 deletions(-)

diff --git a/testcases/kernel/syscalls/mount_setattr/mount_setattr01.c b/testcases/kernel/syscalls/mount_setattr/mount_setattr01.c
index eb32cd91a7fcb4cb303e184dd40d5e10a280874c..2e3fee5cdda905858f89b12a2b3b65255d46297d 100644
--- a/testcases/kernel/syscalls/mount_setattr/mount_setattr01.c
+++ b/testcases/kernel/syscalls/mount_setattr/mount_setattr01.c
@@ -3,10 +3,11 @@
  * Copyright (c) 2022 FUJITSU LIMITED. All rights reserved.
  * Author: Dai Shili <daisl.fnst@fujitsu.com>
  * Author: Chen Hanxiao <chenhx.fnst@fujitsu.com>
+ * Copyright (C) 2025 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
  */
 
 /*\
- * Basic mount_setattr() test.
+ * Basic mount_setattr()/open_tree_attr() test.
  * Test whether the basic mount attributes are set correctly.
  *
  * Verify some MOUNT_SETATTR(2) attributes:
@@ -22,7 +23,8 @@
  * - MOUNT_ATTR_NODIRATIME - prevents updating access time for
  *   directories on this mount
  *
- * The functionality was added in v5.12.
+ * The mount_setattr functionality was added in v5.12, while the open_tree_attr
+ * functionality was added in v6.15.
  */
 
 #define _GNU_SOURCE
@@ -41,6 +43,7 @@
 	}
 
 static int mount_flag, otfd = -1;
+struct mount_attr *attr;
 
 static struct tcase {
 	char *name;
@@ -66,35 +69,61 @@ static void cleanup(void)
 static void setup(void)
 {
 	fsopen_supported_by_kernel();
-	struct stat st = {0};
 
-	if (stat(OT_MNTPOINT, &st) == -1)
+	if (access(OT_MNTPOINT, F_OK) != 0)
 		SAFE_MKDIR(OT_MNTPOINT, 0777);
 }
 
+static int open_tree_variant1(struct mount_attr *attr)
+{
+	tst_res(TINFO, "Variant using open_tree() + mount_setattr()");
+
+	otfd = TST_EXP_FD_SILENT(open_tree(AT_FDCWD, MNTPOINT,
+			AT_EMPTY_PATH | OPEN_TREE_CLONE));
+	if (otfd == -1)
+		return -1;
+
+	TST_EXP_PASS(mount_setattr(otfd, "", AT_EMPTY_PATH,
+			attr, sizeof(*attr)));
+	if (TST_RET == -1) {
+		SAFE_CLOSE(otfd);
+		return -1;
+	}
+
+	return otfd;
+}
+
+static int open_tree_variant2(struct mount_attr *attr)
+{
+	tst_res(TINFO, "Variant using open_tree_attr()");
+
+	otfd = TST_EXP_FD(open_tree_attr(AT_FDCWD, MNTPOINT,
+			AT_EMPTY_PATH | OPEN_TREE_CLONE,
+			attr, sizeof(*attr)));
+
+	return otfd;
+}
+
 static void run(unsigned int n)
 {
 	struct tcase *tc = &tcases[n];
-	struct mount_attr attr = {
-		.attr_set = tc->mount_attrs,
-	};
 	struct statvfs buf;
 
-	TST_EXP_FD_SILENT(open_tree(AT_FDCWD, MNTPOINT, AT_EMPTY_PATH |
-		AT_SYMLINK_NOFOLLOW | OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE));
-	if (!TST_PASS)
-		return;
+	memset(attr, 0, sizeof(*attr));
+	attr->attr_set = tc->mount_attrs;
 
-	otfd = (int)TST_RET;
+	if (tst_variant)
+		otfd = open_tree_variant1(attr);
+	else
+		otfd = open_tree_variant2(attr);
 
-	TST_EXP_PASS_SILENT(mount_setattr(otfd, "", AT_EMPTY_PATH, &attr, sizeof(attr)),
-		"%s set", tc->name);
-	if (!TST_PASS)
-		goto out1;
+	if (otfd == -1)
+		goto out2;
 
 	TST_EXP_PASS_SILENT(move_mount(otfd, "", AT_FDCWD, OT_MNTPOINT, MOVE_MOUNT_F_EMPTY_PATH));
 	if (!TST_PASS)
 		goto out1;
+
 	mount_flag = 1;
 	SAFE_CLOSE(otfd);
 
@@ -123,9 +152,14 @@ static struct tst_test test = {
 	.test = run,
 	.setup = setup,
 	.cleanup = cleanup,
+	.test_variants = 2,
 	.needs_root = 1,
 	.mount_device = 1,
 	.mntpoint = MNTPOINT,
 	.all_filesystems = 1,
-	.skip_filesystems = (const char *const []){"fuse", NULL},
+	.skip_filesystems = (const char *const []) {"fuse", NULL},
+	.bufs = (struct tst_buffers []) {
+		{&attr, .size = sizeof(struct mount_attr)},
+		{}
+	}
 };

-- 
2.51.0


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Re: [LTP] [PATCH v2 1/2] Add open_tree_attr fallback

[Petr Vorel]

Hi Andrea,

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Obviously correct.

Kind regards,
Petr

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Re: [LTP] [PATCH v2 2/2] mount_setattr01: add open_tree_attr variant

[Petr Vorel]

Hi Andrea,

generally LGTM. But it'd be great (can be a separate effort) if you could write
checkers similar to fsopen_supported_by_kernel() for __NR_mount_setattr and
__NR_open_tree_attr. That would save time wasted when looping filesystem on the
variants which aren't supported.

Also while at it, could you fix older typo: 'sucess' => 'success' ?

Reviewed-by: Petr Vorel <pvorel@suse.cz>

...
>  static struct tcase {
>  	char *name;
> @@ -66,35 +69,61 @@ static void cleanup(void)
>  static void setup(void)
>  {
>  	fsopen_supported_by_kernel();
> -	struct stat st = {0};

> -	if (stat(OT_MNTPOINT, &st) == -1)
> +	if (access(OT_MNTPOINT, F_OK) != 0)
Out of curiosity why this change? Faster?

>  		SAFE_MKDIR(OT_MNTPOINT, 0777);
>  }

> +static int open_tree_variant1(struct mount_attr *attr)
> +{
> +	tst_res(TINFO, "Variant using open_tree() + mount_setattr()");
nit: I'm not an english speaker, but I would say "Using variant ..."

> +
> +	otfd = TST_EXP_FD_SILENT(open_tree(AT_FDCWD, MNTPOINT,
> +			AT_EMPTY_PATH | OPEN_TREE_CLONE));
> +	if (otfd == -1)
> +		return -1;
> +
> +	TST_EXP_PASS(mount_setattr(otfd, "", AT_EMPTY_PATH,
> +			attr, sizeof(*attr)));
> +	if (TST_RET == -1) {
> +		SAFE_CLOSE(otfd);
> +		return -1;
> +	}
> +
> +	return otfd;
> +}
> +
> +static int open_tree_variant2(struct mount_attr *attr)
> +{
> +	tst_res(TINFO, "Variant using open_tree_attr()");
And here.

The rest LGTM.

Kind regards,
Petr
> +
> +	otfd = TST_EXP_FD(open_tree_attr(AT_FDCWD, MNTPOINT,
> +			AT_EMPTY_PATH | OPEN_TREE_CLONE,
> +			attr, sizeof(*attr)));
> +
> +	return otfd;
> +}

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Re: [LTP] [PATCH v2 2/2] mount_setattr01: add open_tree_attr variant

[Andrea Cervesato via ltp]

Hi Petr,

On 9/17/25 2:22 PM, Petr Vorel wrote:
>> -	struct stat st = {0};
>> -	if (stat(OT_MNTPOINT, &st) == -1)
>> +	if (access(OT_MNTPOINT, F_OK) != 0)
> Out of curiosity why this change? Faster?

Because in this way there's no need to declare any struct. I will 
achieve the rest of the review and send v3.

- Andrea

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