[PATCH 0/5] filesystems selftests cleanups

[PATCH 0/5] filesystems selftests cleanups

[Amir Goldstein]

Christian,

I was cleaning up my test env today to prepare for the test
of fanotify mount ns notifications inside userns and tried to
disolve the headers_install depenency.

These patches got rid of the dependency for my kvm setup for the
affected filesystems tests.

Building with TOOLS_INCLUDES dir was recommended by John Hubbard [1].

NOTE #1: these patches are based on a merge of vfs-6.16.mount
(changes wrappers.h) into v6.15-rc5 (changes mount-notify_test.c),
so if this cleanup is acceptable, we should probably setup a stable
branch for 6.16, so that I can base my fanotify patches on it.

NOTE #2: some of the defines in wrappers.h are only left for
mount_setattr, which was not converted to use TOOLS_INCLUDES.
I did not want to mess with it.

Thanks,
Amir.

[1] https://lore.kernel.org/linux-fsdevel/6dd57f0e-34b4-4456-854b-a8abdba9163b@nvidia.com/

Amir Goldstein (5):
  selftests/filesystems: move wrapper.h out of overlayfs subdir
  selftests/fs/statmount: build with tools include dir
  selftests/fs/mount-notify: build with tools include dir
  selftests/filesystems: create get_unique_mnt_id() helper
  selftests/filesystems: create setup_userns() helper

 tools/include/uapi/linux/fanotify.h           | 274 ++++++++++++++++++
 tools/include/uapi/linux/mount.h              | 235 +++++++++++++++
 tools/include/uapi/linux/nsfs.h               |  45 +++
 .../filesystems/mount-notify/Makefile         |   6 +-
 .../mount-notify/mount-notify_test.c          |  38 +--
 .../selftests/filesystems/overlayfs/Makefile  |   2 +-
 .../filesystems/overlayfs/dev_in_maps.c       |   2 +-
 .../overlayfs/set_layers_via_fds.c            |   2 +-
 .../selftests/filesystems/statmount/Makefile  |   6 +-
 .../filesystems/statmount/statmount.h         |  12 +
 .../filesystems/statmount/statmount_test_ns.c |  88 +-----
 tools/testing/selftests/filesystems/utils.c   |  85 ++++++
 tools/testing/selftests/filesystems/utils.h   |   3 +
 .../filesystems/{overlayfs => }/wrappers.h    |   0
 .../testing/selftests/mount_setattr/Makefile  |   2 +
 .../mount_setattr/mount_setattr_test.c        |   2 +-
 16 files changed, 684 insertions(+), 118 deletions(-)
 create mode 100644 tools/include/uapi/linux/fanotify.h
 create mode 100644 tools/include/uapi/linux/mount.h
 create mode 100644 tools/include/uapi/linux/nsfs.h
 rename tools/testing/selftests/filesystems/{overlayfs => }/wrappers.h (100%)

-- 
2.34.1

[PATCH 1/5] selftests/filesystems: move wrapper.h out of overlayfs subdir

[Amir Goldstein]

This is not an overlayfs specific header.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tools/testing/selftests/filesystems/overlayfs/Makefile          | 2 +-
 tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c     | 2 +-
 .../selftests/filesystems/overlayfs/set_layers_via_fds.c        | 2 +-
 tools/testing/selftests/filesystems/{overlayfs => }/wrappers.h  | 0
 tools/testing/selftests/mount_setattr/Makefile                  | 2 ++
 tools/testing/selftests/mount_setattr/mount_setattr_test.c      | 2 +-
 6 files changed, 6 insertions(+), 4 deletions(-)
 rename tools/testing/selftests/filesystems/{overlayfs => }/wrappers.h (100%)

diff --git a/tools/testing/selftests/filesystems/overlayfs/Makefile b/tools/testing/selftests/filesystems/overlayfs/Makefile
index 6c661232b3b5..d3ad4a77db9b 100644
--- a/tools/testing/selftests/filesystems/overlayfs/Makefile
+++ b/tools/testing/selftests/filesystems/overlayfs/Makefile
@@ -4,7 +4,7 @@ CFLAGS += -Wall
 CFLAGS += $(KHDR_INCLUDES)
 LDLIBS += -lcap
 
-LOCAL_HDRS += wrappers.h log.h
+LOCAL_HDRS += ../wrappers.h log.h
 
 TEST_GEN_PROGS := dev_in_maps
 TEST_GEN_PROGS += set_layers_via_fds
diff --git a/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c b/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
index 3b796264223f..31db54b00e64 100644
--- a/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
+++ b/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
@@ -17,7 +17,7 @@
 
 #include "../../kselftest.h"
 #include "log.h"
-#include "wrappers.h"
+#include "../wrappers.h"
 
 static long get_file_dev_and_inode(void *addr, struct statx *stx)
 {
diff --git a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
index 5074e64e74a8..dc0449fa628f 100644
--- a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
+++ b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
@@ -16,7 +16,7 @@
 #include "../../pidfd/pidfd.h"
 #include "log.h"
 #include "../utils.h"
-#include "wrappers.h"
+#include "../wrappers.h"
 
 FIXTURE(set_layers_via_fds) {
 	int pidfd;
diff --git a/tools/testing/selftests/filesystems/overlayfs/wrappers.h b/tools/testing/selftests/filesystems/wrappers.h
similarity index 100%
rename from tools/testing/selftests/filesystems/overlayfs/wrappers.h
rename to tools/testing/selftests/filesystems/wrappers.h
diff --git a/tools/testing/selftests/mount_setattr/Makefile b/tools/testing/selftests/mount_setattr/Makefile
index 0c0d7b1234c1..4d4f810cdf2c 100644
--- a/tools/testing/selftests/mount_setattr/Makefile
+++ b/tools/testing/selftests/mount_setattr/Makefile
@@ -2,6 +2,8 @@
 # Makefile for mount selftests.
 CFLAGS = -g $(KHDR_INCLUDES) -Wall -O2 -pthread
 
+LOCAL_HDRS += ../filesystems/wrappers.h
+
 TEST_GEN_PROGS := mount_setattr_test
 
 include ../lib.mk
diff --git a/tools/testing/selftests/mount_setattr/mount_setattr_test.c b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
index 432d9af23ab2..9e933925b3c2 100644
--- a/tools/testing/selftests/mount_setattr/mount_setattr_test.c
+++ b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
@@ -20,7 +20,7 @@
 #include <stdarg.h>
 #include <linux/mount.h>
 
-#include "../filesystems/overlayfs/wrappers.h"
+#include "../filesystems/wrappers.h"
 #include "../kselftest_harness.h"
 
 #ifndef CLONE_NEWNS
-- 
2.34.1

Re: [PATCH 1/5] selftests/filesystems: move wrapper.h out of overlayfs subdir

[John Hubbard]

On 5/7/25 1:42 PM, Amir Goldstein wrote:
> This is not an overlayfs specific header.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   tools/testing/selftests/filesystems/overlayfs/Makefile          | 2 +-
>   tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c     | 2 +-
>   .../selftests/filesystems/overlayfs/set_layers_via_fds.c        | 2 +-
>   tools/testing/selftests/filesystems/{overlayfs => }/wrappers.h  | 0
>   tools/testing/selftests/mount_setattr/Makefile                  | 2 ++
>   tools/testing/selftests/mount_setattr/mount_setattr_test.c      | 2 +-
>   6 files changed, 6 insertions(+), 4 deletions(-)
>   rename tools/testing/selftests/filesystems/{overlayfs => }/wrappers.h (100%)

Simple and clearly correct by inspection, yes.

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,
-- 
John Hubbard

> 
> diff --git a/tools/testing/selftests/filesystems/overlayfs/Makefile b/tools/testing/selftests/filesystems/overlayfs/Makefile
> index 6c661232b3b5..d3ad4a77db9b 100644
> --- a/tools/testing/selftests/filesystems/overlayfs/Makefile
> +++ b/tools/testing/selftests/filesystems/overlayfs/Makefile
> @@ -4,7 +4,7 @@ CFLAGS += -Wall
>   CFLAGS += $(KHDR_INCLUDES)
>   LDLIBS += -lcap
>   
> -LOCAL_HDRS += wrappers.h log.h
> +LOCAL_HDRS += ../wrappers.h log.h
>   
>   TEST_GEN_PROGS := dev_in_maps
>   TEST_GEN_PROGS += set_layers_via_fds
> diff --git a/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c b/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
> index 3b796264223f..31db54b00e64 100644
> --- a/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
> +++ b/tools/testing/selftests/filesystems/overlayfs/dev_in_maps.c
> @@ -17,7 +17,7 @@
>   
>   #include "../../kselftest.h"
>   #include "log.h"
> -#include "wrappers.h"
> +#include "../wrappers.h"
>   
>   static long get_file_dev_and_inode(void *addr, struct statx *stx)
>   {
> diff --git a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> index 5074e64e74a8..dc0449fa628f 100644
> --- a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> +++ b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> @@ -16,7 +16,7 @@
>   #include "../../pidfd/pidfd.h"
>   #include "log.h"
>   #include "../utils.h"
> -#include "wrappers.h"
> +#include "../wrappers.h"
>   
>   FIXTURE(set_layers_via_fds) {
>   	int pidfd;
> diff --git a/tools/testing/selftests/filesystems/overlayfs/wrappers.h b/tools/testing/selftests/filesystems/wrappers.h
> similarity index 100%
> rename from tools/testing/selftests/filesystems/overlayfs/wrappers.h
> rename to tools/testing/selftests/filesystems/wrappers.h
> diff --git a/tools/testing/selftests/mount_setattr/Makefile b/tools/testing/selftests/mount_setattr/Makefile
> index 0c0d7b1234c1..4d4f810cdf2c 100644
> --- a/tools/testing/selftests/mount_setattr/Makefile
> +++ b/tools/testing/selftests/mount_setattr/Makefile
> @@ -2,6 +2,8 @@
>   # Makefile for mount selftests.
>   CFLAGS = -g $(KHDR_INCLUDES) -Wall -O2 -pthread
>   
> +LOCAL_HDRS += ../filesystems/wrappers.h
> +
>   TEST_GEN_PROGS := mount_setattr_test
>   
>   include ../lib.mk
> diff --git a/tools/testing/selftests/mount_setattr/mount_setattr_test.c b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
> index 432d9af23ab2..9e933925b3c2 100644
> --- a/tools/testing/selftests/mount_setattr/mount_setattr_test.c
> +++ b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
> @@ -20,7 +20,7 @@
>   #include <stdarg.h>
>   #include <linux/mount.h>
>   
> -#include "../filesystems/overlayfs/wrappers.h"
> +#include "../filesystems/wrappers.h"
>   #include "../kselftest_harness.h"
>   
>   #ifndef CLONE_NEWNS

[PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Amir Goldstein]

Copy the required headers files (mount.h, nsfs.h) to the
tools include dir and define the statmount/listmount syscalls
for x86_64 to decouple dependency with headers_install for the
common case.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tools/include/uapi/linux/mount.h              | 235 ++++++++++++++++++
 tools/include/uapi/linux/nsfs.h               |  45 ++++
 .../selftests/filesystems/statmount/Makefile  |   3 +-
 .../filesystems/statmount/statmount.h         |  12 +
 4 files changed, 294 insertions(+), 1 deletion(-)
 create mode 100644 tools/include/uapi/linux/mount.h
 create mode 100644 tools/include/uapi/linux/nsfs.h

diff --git a/tools/include/uapi/linux/mount.h b/tools/include/uapi/linux/mount.h
new file mode 100644
index 000000000000..7fa67c2031a5
--- /dev/null
+++ b/tools/include/uapi/linux/mount.h
@@ -0,0 +1,235 @@
+#ifndef _UAPI_LINUX_MOUNT_H
+#define _UAPI_LINUX_MOUNT_H
+
+#include <linux/types.h>
+
+/*
+ * These are the fs-independent mount-flags: up to 32 flags are supported
+ *
+ * Usage of these is restricted within the kernel to core mount(2) code and
+ * callers of sys_mount() only.  Filesystems should be using the SB_*
+ * equivalent instead.
+ */
+#define MS_RDONLY	 1	/* Mount read-only */
+#define MS_NOSUID	 2	/* Ignore suid and sgid bits */
+#define MS_NODEV	 4	/* Disallow access to device special files */
+#define MS_NOEXEC	 8	/* Disallow program execution */
+#define MS_SYNCHRONOUS	16	/* Writes are synced at once */
+#define MS_REMOUNT	32	/* Alter flags of a mounted FS */
+#define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
+#define MS_DIRSYNC	128	/* Directory modifications are synchronous */
+#define MS_NOSYMFOLLOW	256	/* Do not follow symlinks */
+#define MS_NOATIME	1024	/* Do not update access times. */
+#define MS_NODIRATIME	2048	/* Do not update directory access times */
+#define MS_BIND		4096
+#define MS_MOVE		8192
+#define MS_REC		16384
+#define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
+				   MS_VERBOSE is deprecated. */
+#define MS_SILENT	32768
+#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
+#define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
+#define MS_PRIVATE	(1<<18)	/* change to private */
+#define MS_SLAVE	(1<<19)	/* change to slave */
+#define MS_SHARED	(1<<20)	/* change to shared */
+#define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
+#define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
+#define MS_I_VERSION	(1<<23) /* Update inode I_version field */
+#define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
+#define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
+
+/* These sb flags are internal to the kernel */
+#define MS_SUBMOUNT     (1<<26)
+#define MS_NOREMOTELOCK	(1<<27)
+#define MS_NOSEC	(1<<28)
+#define MS_BORN		(1<<29)
+#define MS_ACTIVE	(1<<30)
+#define MS_NOUSER	(1<<31)
+
+/*
+ * Superblock flags that can be altered by MS_REMOUNT
+ */
+#define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION|\
+			 MS_LAZYTIME)
+
+/*
+ * Old magic mount flag and mask
+ */
+#define MS_MGC_VAL 0xC0ED0000
+#define MS_MGC_MSK 0xffff0000
+
+/*
+ * open_tree() flags.
+ */
+#define OPEN_TREE_CLONE		1		/* Clone the target tree and attach the clone */
+#define OPEN_TREE_CLOEXEC	O_CLOEXEC	/* Close the file on execve() */
+
+/*
+ * move_mount() flags.
+ */
+#define MOVE_MOUNT_F_SYMLINKS		0x00000001 /* Follow symlinks on from path */
+#define MOVE_MOUNT_F_AUTOMOUNTS		0x00000002 /* Follow automounts on from path */
+#define MOVE_MOUNT_F_EMPTY_PATH		0x00000004 /* Empty from path permitted */
+#define MOVE_MOUNT_T_SYMLINKS		0x00000010 /* Follow symlinks on to path */
+#define MOVE_MOUNT_T_AUTOMOUNTS		0x00000020 /* Follow automounts on to path */
+#define MOVE_MOUNT_T_EMPTY_PATH		0x00000040 /* Empty to path permitted */
+#define MOVE_MOUNT_SET_GROUP		0x00000100 /* Set sharing group instead */
+#define MOVE_MOUNT_BENEATH		0x00000200 /* Mount beneath top mount */
+#define MOVE_MOUNT__MASK		0x00000377
+
+/*
+ * fsopen() flags.
+ */
+#define FSOPEN_CLOEXEC		0x00000001
+
+/*
+ * fspick() flags.
+ */
+#define FSPICK_CLOEXEC		0x00000001
+#define FSPICK_SYMLINK_NOFOLLOW	0x00000002
+#define FSPICK_NO_AUTOMOUNT	0x00000004
+#define FSPICK_EMPTY_PATH	0x00000008
+
+/*
+ * The type of fsconfig() call made.
+ */
+enum fsconfig_command {
+	FSCONFIG_SET_FLAG	= 0,	/* Set parameter, supplying no value */
+	FSCONFIG_SET_STRING	= 1,	/* Set parameter, supplying a string value */
+	FSCONFIG_SET_BINARY	= 2,	/* Set parameter, supplying a binary blob value */
+	FSCONFIG_SET_PATH	= 3,	/* Set parameter, supplying an object by path */
+	FSCONFIG_SET_PATH_EMPTY	= 4,	/* Set parameter, supplying an object by (empty) path */
+	FSCONFIG_SET_FD		= 5,	/* Set parameter, supplying an object by fd */
+	FSCONFIG_CMD_CREATE	= 6,	/* Create new or reuse existing superblock */
+	FSCONFIG_CMD_RECONFIGURE = 7,	/* Invoke superblock reconfiguration */
+	FSCONFIG_CMD_CREATE_EXCL = 8,	/* Create new superblock, fail if reusing existing superblock */
+};
+
+/*
+ * fsmount() flags.
+ */
+#define FSMOUNT_CLOEXEC		0x00000001
+
+/*
+ * Mount attributes.
+ */
+#define MOUNT_ATTR_RDONLY	0x00000001 /* Mount read-only */
+#define MOUNT_ATTR_NOSUID	0x00000002 /* Ignore suid and sgid bits */
+#define MOUNT_ATTR_NODEV	0x00000004 /* Disallow access to device special files */
+#define MOUNT_ATTR_NOEXEC	0x00000008 /* Disallow program execution */
+#define MOUNT_ATTR__ATIME	0x00000070 /* Setting on how atime should be updated */
+#define MOUNT_ATTR_RELATIME	0x00000000 /* - Update atime relative to mtime/ctime. */
+#define MOUNT_ATTR_NOATIME	0x00000010 /* - Do not update access times. */
+#define MOUNT_ATTR_STRICTATIME	0x00000020 /* - Always perform atime updates */
+#define MOUNT_ATTR_NODIRATIME	0x00000080 /* Do not update directory access times */
+#define MOUNT_ATTR_IDMAP	0x00100000 /* Idmap mount to @userns_fd in struct mount_attr. */
+#define MOUNT_ATTR_NOSYMFOLLOW	0x00200000 /* Do not follow symlinks */
+
+/*
+ * mount_setattr()
+ */
+struct mount_attr {
+	__u64 attr_set;
+	__u64 attr_clr;
+	__u64 propagation;
+	__u64 userns_fd;
+};
+
+/* List of all mount_attr versions. */
+#define MOUNT_ATTR_SIZE_VER0	32 /* sizeof first published struct */
+
+
+/*
+ * Structure for getting mount/superblock/filesystem info with statmount(2).
+ *
+ * The interface is similar to statx(2): individual fields or groups can be
+ * selected with the @mask argument of statmount().  Kernel will set the @mask
+ * field according to the supported fields.
+ *
+ * If string fields are selected, then the caller needs to pass a buffer that
+ * has space after the fixed part of the structure.  Nul terminated strings are
+ * copied there and offsets relative to @str are stored in the relevant fields.
+ * If the buffer is too small, then EOVERFLOW is returned.  The actually used
+ * size is returned in @size.
+ */
+struct statmount {
+	__u32 size;		/* Total size, including strings */
+	__u32 mnt_opts;		/* [str] Options (comma separated, escaped) */
+	__u64 mask;		/* What results were written */
+	__u32 sb_dev_major;	/* Device ID */
+	__u32 sb_dev_minor;
+	__u64 sb_magic;		/* ..._SUPER_MAGIC */
+	__u32 sb_flags;		/* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
+	__u32 fs_type;		/* [str] Filesystem type */
+	__u64 mnt_id;		/* Unique ID of mount */
+	__u64 mnt_parent_id;	/* Unique ID of parent (for root == mnt_id) */
+	__u32 mnt_id_old;	/* Reused IDs used in proc/.../mountinfo */
+	__u32 mnt_parent_id_old;
+	__u64 mnt_attr;		/* MOUNT_ATTR_... */
+	__u64 mnt_propagation;	/* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
+	__u64 mnt_peer_group;	/* ID of shared peer group */
+	__u64 mnt_master;	/* Mount receives propagation from this ID */
+	__u64 propagate_from;	/* Propagation from in current namespace */
+	__u32 mnt_root;		/* [str] Root of mount relative to root of fs */
+	__u32 mnt_point;	/* [str] Mountpoint relative to current root */
+	__u64 mnt_ns_id;	/* ID of the mount namespace */
+	__u32 fs_subtype;	/* [str] Subtype of fs_type (if any) */
+	__u32 sb_source;	/* [str] Source string of the mount */
+	__u32 opt_num;		/* Number of fs options */
+	__u32 opt_array;	/* [str] Array of nul terminated fs options */
+	__u32 opt_sec_num;	/* Number of security options */
+	__u32 opt_sec_array;	/* [str] Array of nul terminated security options */
+	__u64 supported_mask;	/* Mask flags that this kernel supports */
+	__u32 mnt_uidmap_num;	/* Number of uid mappings */
+	__u32 mnt_uidmap;	/* [str] Array of uid mappings (as seen from callers namespace) */
+	__u32 mnt_gidmap_num;	/* Number of gid mappings */
+	__u32 mnt_gidmap;	/* [str] Array of gid mappings (as seen from callers namespace) */
+	__u64 __spare2[43];
+	char str[];		/* Variable size part containing strings */
+};
+
+/*
+ * Structure for passing mount ID and miscellaneous parameters to statmount(2)
+ * and listmount(2).
+ *
+ * For statmount(2) @param represents the request mask.
+ * For listmount(2) @param represents the last listed mount id (or zero).
+ */
+struct mnt_id_req {
+	__u32 size;
+	__u32 spare;
+	__u64 mnt_id;
+	__u64 param;
+	__u64 mnt_ns_id;
+};
+
+/* List of all mnt_id_req versions. */
+#define MNT_ID_REQ_SIZE_VER0	24 /* sizeof first published struct */
+#define MNT_ID_REQ_SIZE_VER1	32 /* sizeof second published struct */
+
+/*
+ * @mask bits for statmount(2)
+ */
+#define STATMOUNT_SB_BASIC		0x00000001U     /* Want/got sb_... */
+#define STATMOUNT_MNT_BASIC		0x00000002U	/* Want/got mnt_... */
+#define STATMOUNT_PROPAGATE_FROM	0x00000004U	/* Want/got propagate_from */
+#define STATMOUNT_MNT_ROOT		0x00000008U	/* Want/got mnt_root  */
+#define STATMOUNT_MNT_POINT		0x00000010U	/* Want/got mnt_point */
+#define STATMOUNT_FS_TYPE		0x00000020U	/* Want/got fs_type */
+#define STATMOUNT_MNT_NS_ID		0x00000040U	/* Want/got mnt_ns_id */
+#define STATMOUNT_MNT_OPTS		0x00000080U	/* Want/got mnt_opts */
+#define STATMOUNT_FS_SUBTYPE		0x00000100U	/* Want/got fs_subtype */
+#define STATMOUNT_SB_SOURCE		0x00000200U	/* Want/got sb_source */
+#define STATMOUNT_OPT_ARRAY		0x00000400U	/* Want/got opt_... */
+#define STATMOUNT_OPT_SEC_ARRAY		0x00000800U	/* Want/got opt_sec... */
+#define STATMOUNT_SUPPORTED_MASK	0x00001000U	/* Want/got supported mask flags */
+#define STATMOUNT_MNT_UIDMAP		0x00002000U	/* Want/got uidmap... */
+#define STATMOUNT_MNT_GIDMAP		0x00004000U	/* Want/got gidmap... */
+
+/*
+ * Special @mnt_id values that can be passed to listmount
+ */
+#define LSMT_ROOT		0xffffffffffffffff	/* root mount */
+#define LISTMOUNT_REVERSE	(1 << 0) /* List later mounts first */
+
+#endif /* _UAPI_LINUX_MOUNT_H */
diff --git a/tools/include/uapi/linux/nsfs.h b/tools/include/uapi/linux/nsfs.h
new file mode 100644
index 000000000000..34127653fd00
--- /dev/null
+++ b/tools/include/uapi/linux/nsfs.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef __LINUX_NSFS_H
+#define __LINUX_NSFS_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define NSIO	0xb7
+
+/* Returns a file descriptor that refers to an owning user namespace */
+#define NS_GET_USERNS		_IO(NSIO, 0x1)
+/* Returns a file descriptor that refers to a parent namespace */
+#define NS_GET_PARENT		_IO(NSIO, 0x2)
+/* Returns the type of namespace (CLONE_NEW* value) referred to by
+   file descriptor */
+#define NS_GET_NSTYPE		_IO(NSIO, 0x3)
+/* Get owner UID (in the caller's user namespace) for a user namespace */
+#define NS_GET_OWNER_UID	_IO(NSIO, 0x4)
+/* Get the id for a mount namespace */
+#define NS_GET_MNTNS_ID		_IOR(NSIO, 0x5, __u64)
+/* Translate pid from target pid namespace into the caller's pid namespace. */
+#define NS_GET_PID_FROM_PIDNS	_IOR(NSIO, 0x6, int)
+/* Return thread-group leader id of pid in the callers pid namespace. */
+#define NS_GET_TGID_FROM_PIDNS	_IOR(NSIO, 0x7, int)
+/* Translate pid from caller's pid namespace into a target pid namespace. */
+#define NS_GET_PID_IN_PIDNS	_IOR(NSIO, 0x8, int)
+/* Return thread-group leader id of pid in the target pid namespace. */
+#define NS_GET_TGID_IN_PIDNS	_IOR(NSIO, 0x9, int)
+
+struct mnt_ns_info {
+	__u32 size;
+	__u32 nr_mounts;
+	__u64 mnt_ns_id;
+};
+
+#define MNT_NS_INFO_SIZE_VER0 16 /* size of first published struct */
+
+/* Get information about namespace. */
+#define NS_MNT_GET_INFO		_IOR(NSIO, 10, struct mnt_ns_info)
+/* Get next namespace. */
+#define NS_MNT_GET_NEXT		_IOR(NSIO, 11, struct mnt_ns_info)
+/* Get previous namespace. */
+#define NS_MNT_GET_PREV		_IOR(NSIO, 12, struct mnt_ns_info)
+
+#endif /* __LINUX_NSFS_H */
diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
index 14ee91a41650..19adebfc2620 100644
--- a/tools/testing/selftests/filesystems/statmount/Makefile
+++ b/tools/testing/selftests/filesystems/statmount/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
+CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
+
 TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
 
 include ../../lib.mk
diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
index a7a5289ddae9..e84d47fadd0b 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount.h
+++ b/tools/testing/selftests/filesystems/statmount/statmount.h
@@ -7,6 +7,18 @@
 #include <linux/mount.h>
 #include <asm/unistd.h>
 
+#ifndef __NR_statmount
+#if defined(__x86_64__)
+#define __NR_statmount	457
+#endif
+#endif
+
+#ifndef __NR_listmount
+#if defined(__x86_64__)
+#define __NR_listmount	458
+#endif
+#endif
+
 static inline int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask,
 			    struct statmount *buf, size_t bufsize,
 			    unsigned int flags)
-- 
2.34.1

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[John Hubbard]

On 5/7/25 1:42 PM, Amir Goldstein wrote:
> Copy the required headers files (mount.h, nsfs.h) to the
> tools include dir and define the statmount/listmount syscalls
> for x86_64 to decouple dependency with headers_install for the
> common case.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   tools/include/uapi/linux/mount.h              | 235 ++++++++++++++++++
>   tools/include/uapi/linux/nsfs.h               |  45 ++++
>   .../selftests/filesystems/statmount/Makefile  |   3 +-
>   .../filesystems/statmount/statmount.h         |  12 +
>   4 files changed, 294 insertions(+), 1 deletion(-)
>   create mode 100644 tools/include/uapi/linux/mount.h
>   create mode 100644 tools/include/uapi/linux/nsfs.h
> 
> diff --git a/tools/include/uapi/linux/mount.h b/tools/include/uapi/linux/mount.h
> new file mode 100644
> index 000000000000..7fa67c2031a5
> --- /dev/null
> +++ b/tools/include/uapi/linux/mount.h
> @@ -0,0 +1,235 @@
> +#ifndef _UAPI_LINUX_MOUNT_H
> +#define _UAPI_LINUX_MOUNT_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * These are the fs-independent mount-flags: up to 32 flags are supported
> + *
> + * Usage of these is restricted within the kernel to core mount(2) code and
> + * callers of sys_mount() only.  Filesystems should be using the SB_*
> + * equivalent instead.
> + */
> +#define MS_RDONLY	 1	/* Mount read-only */
> +#define MS_NOSUID	 2	/* Ignore suid and sgid bits */
> +#define MS_NODEV	 4	/* Disallow access to device special files */
> +#define MS_NOEXEC	 8	/* Disallow program execution */
> +#define MS_SYNCHRONOUS	16	/* Writes are synced at once */
> +#define MS_REMOUNT	32	/* Alter flags of a mounted FS */
> +#define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
> +#define MS_DIRSYNC	128	/* Directory modifications are synchronous */
> +#define MS_NOSYMFOLLOW	256	/* Do not follow symlinks */
> +#define MS_NOATIME	1024	/* Do not update access times. */
> +#define MS_NODIRATIME	2048	/* Do not update directory access times */
> +#define MS_BIND		4096
> +#define MS_MOVE		8192
> +#define MS_REC		16384
> +#define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
> +				   MS_VERBOSE is deprecated. */
> +#define MS_SILENT	32768
> +#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
> +#define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
> +#define MS_PRIVATE	(1<<18)	/* change to private */
> +#define MS_SLAVE	(1<<19)	/* change to slave */
> +#define MS_SHARED	(1<<20)	/* change to shared */
> +#define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
> +#define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
> +#define MS_I_VERSION	(1<<23) /* Update inode I_version field */
> +#define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
> +#define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
> +
> +/* These sb flags are internal to the kernel */
> +#define MS_SUBMOUNT     (1<<26)
> +#define MS_NOREMOTELOCK	(1<<27)
> +#define MS_NOSEC	(1<<28)
> +#define MS_BORN		(1<<29)
> +#define MS_ACTIVE	(1<<30)
> +#define MS_NOUSER	(1<<31)
> +
> +/*
> + * Superblock flags that can be altered by MS_REMOUNT
> + */
> +#define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION|\
> +			 MS_LAZYTIME)
> +
> +/*
> + * Old magic mount flag and mask
> + */
> +#define MS_MGC_VAL 0xC0ED0000
> +#define MS_MGC_MSK 0xffff0000
> +
> +/*
> + * open_tree() flags.
> + */
> +#define OPEN_TREE_CLONE		1		/* Clone the target tree and attach the clone */
> +#define OPEN_TREE_CLOEXEC	O_CLOEXEC	/* Close the file on execve() */
> +
> +/*
> + * move_mount() flags.
> + */
> +#define MOVE_MOUNT_F_SYMLINKS		0x00000001 /* Follow symlinks on from path */
> +#define MOVE_MOUNT_F_AUTOMOUNTS		0x00000002 /* Follow automounts on from path */
> +#define MOVE_MOUNT_F_EMPTY_PATH		0x00000004 /* Empty from path permitted */
> +#define MOVE_MOUNT_T_SYMLINKS		0x00000010 /* Follow symlinks on to path */
> +#define MOVE_MOUNT_T_AUTOMOUNTS		0x00000020 /* Follow automounts on to path */
> +#define MOVE_MOUNT_T_EMPTY_PATH		0x00000040 /* Empty to path permitted */
> +#define MOVE_MOUNT_SET_GROUP		0x00000100 /* Set sharing group instead */
> +#define MOVE_MOUNT_BENEATH		0x00000200 /* Mount beneath top mount */
> +#define MOVE_MOUNT__MASK		0x00000377
> +
> +/*
> + * fsopen() flags.
> + */
> +#define FSOPEN_CLOEXEC		0x00000001
> +
> +/*
> + * fspick() flags.
> + */
> +#define FSPICK_CLOEXEC		0x00000001
> +#define FSPICK_SYMLINK_NOFOLLOW	0x00000002
> +#define FSPICK_NO_AUTOMOUNT	0x00000004
> +#define FSPICK_EMPTY_PATH	0x00000008
> +
> +/*
> + * The type of fsconfig() call made.
> + */
> +enum fsconfig_command {
> +	FSCONFIG_SET_FLAG	= 0,	/* Set parameter, supplying no value */
> +	FSCONFIG_SET_STRING	= 1,	/* Set parameter, supplying a string value */
> +	FSCONFIG_SET_BINARY	= 2,	/* Set parameter, supplying a binary blob value */
> +	FSCONFIG_SET_PATH	= 3,	/* Set parameter, supplying an object by path */
> +	FSCONFIG_SET_PATH_EMPTY	= 4,	/* Set parameter, supplying an object by (empty) path */
> +	FSCONFIG_SET_FD		= 5,	/* Set parameter, supplying an object by fd */
> +	FSCONFIG_CMD_CREATE	= 6,	/* Create new or reuse existing superblock */
> +	FSCONFIG_CMD_RECONFIGURE = 7,	/* Invoke superblock reconfiguration */
> +	FSCONFIG_CMD_CREATE_EXCL = 8,	/* Create new superblock, fail if reusing existing superblock */
> +};
> +
> +/*
> + * fsmount() flags.
> + */
> +#define FSMOUNT_CLOEXEC		0x00000001
> +
> +/*
> + * Mount attributes.
> + */
> +#define MOUNT_ATTR_RDONLY	0x00000001 /* Mount read-only */
> +#define MOUNT_ATTR_NOSUID	0x00000002 /* Ignore suid and sgid bits */
> +#define MOUNT_ATTR_NODEV	0x00000004 /* Disallow access to device special files */
> +#define MOUNT_ATTR_NOEXEC	0x00000008 /* Disallow program execution */
> +#define MOUNT_ATTR__ATIME	0x00000070 /* Setting on how atime should be updated */
> +#define MOUNT_ATTR_RELATIME	0x00000000 /* - Update atime relative to mtime/ctime. */
> +#define MOUNT_ATTR_NOATIME	0x00000010 /* - Do not update access times. */
> +#define MOUNT_ATTR_STRICTATIME	0x00000020 /* - Always perform atime updates */
> +#define MOUNT_ATTR_NODIRATIME	0x00000080 /* Do not update directory access times */
> +#define MOUNT_ATTR_IDMAP	0x00100000 /* Idmap mount to @userns_fd in struct mount_attr. */
> +#define MOUNT_ATTR_NOSYMFOLLOW	0x00200000 /* Do not follow symlinks */
> +
> +/*
> + * mount_setattr()
> + */
> +struct mount_attr {
> +	__u64 attr_set;
> +	__u64 attr_clr;
> +	__u64 propagation;
> +	__u64 userns_fd;
> +};
> +
> +/* List of all mount_attr versions. */
> +#define MOUNT_ATTR_SIZE_VER0	32 /* sizeof first published struct */
> +
> +
> +/*
> + * Structure for getting mount/superblock/filesystem info with statmount(2).
> + *
> + * The interface is similar to statx(2): individual fields or groups can be
> + * selected with the @mask argument of statmount().  Kernel will set the @mask
> + * field according to the supported fields.
> + *
> + * If string fields are selected, then the caller needs to pass a buffer that
> + * has space after the fixed part of the structure.  Nul terminated strings are
> + * copied there and offsets relative to @str are stored in the relevant fields.
> + * If the buffer is too small, then EOVERFLOW is returned.  The actually used
> + * size is returned in @size.
> + */
> +struct statmount {
> +	__u32 size;		/* Total size, including strings */
> +	__u32 mnt_opts;		/* [str] Options (comma separated, escaped) */
> +	__u64 mask;		/* What results were written */
> +	__u32 sb_dev_major;	/* Device ID */
> +	__u32 sb_dev_minor;
> +	__u64 sb_magic;		/* ..._SUPER_MAGIC */
> +	__u32 sb_flags;		/* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
> +	__u32 fs_type;		/* [str] Filesystem type */
> +	__u64 mnt_id;		/* Unique ID of mount */
> +	__u64 mnt_parent_id;	/* Unique ID of parent (for root == mnt_id) */
> +	__u32 mnt_id_old;	/* Reused IDs used in proc/.../mountinfo */
> +	__u32 mnt_parent_id_old;
> +	__u64 mnt_attr;		/* MOUNT_ATTR_... */
> +	__u64 mnt_propagation;	/* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
> +	__u64 mnt_peer_group;	/* ID of shared peer group */
> +	__u64 mnt_master;	/* Mount receives propagation from this ID */
> +	__u64 propagate_from;	/* Propagation from in current namespace */
> +	__u32 mnt_root;		/* [str] Root of mount relative to root of fs */
> +	__u32 mnt_point;	/* [str] Mountpoint relative to current root */
> +	__u64 mnt_ns_id;	/* ID of the mount namespace */
> +	__u32 fs_subtype;	/* [str] Subtype of fs_type (if any) */
> +	__u32 sb_source;	/* [str] Source string of the mount */
> +	__u32 opt_num;		/* Number of fs options */
> +	__u32 opt_array;	/* [str] Array of nul terminated fs options */
> +	__u32 opt_sec_num;	/* Number of security options */
> +	__u32 opt_sec_array;	/* [str] Array of nul terminated security options */
> +	__u64 supported_mask;	/* Mask flags that this kernel supports */
> +	__u32 mnt_uidmap_num;	/* Number of uid mappings */
> +	__u32 mnt_uidmap;	/* [str] Array of uid mappings (as seen from callers namespace) */
> +	__u32 mnt_gidmap_num;	/* Number of gid mappings */
> +	__u32 mnt_gidmap;	/* [str] Array of gid mappings (as seen from callers namespace) */
> +	__u64 __spare2[43];
> +	char str[];		/* Variable size part containing strings */
> +};
> +
> +/*
> + * Structure for passing mount ID and miscellaneous parameters to statmount(2)
> + * and listmount(2).
> + *
> + * For statmount(2) @param represents the request mask.
> + * For listmount(2) @param represents the last listed mount id (or zero).
> + */
> +struct mnt_id_req {
> +	__u32 size;
> +	__u32 spare;
> +	__u64 mnt_id;
> +	__u64 param;
> +	__u64 mnt_ns_id;
> +};
> +
> +/* List of all mnt_id_req versions. */
> +#define MNT_ID_REQ_SIZE_VER0	24 /* sizeof first published struct */
> +#define MNT_ID_REQ_SIZE_VER1	32 /* sizeof second published struct */
> +
> +/*
> + * @mask bits for statmount(2)
> + */
> +#define STATMOUNT_SB_BASIC		0x00000001U     /* Want/got sb_... */
> +#define STATMOUNT_MNT_BASIC		0x00000002U	/* Want/got mnt_... */
> +#define STATMOUNT_PROPAGATE_FROM	0x00000004U	/* Want/got propagate_from */
> +#define STATMOUNT_MNT_ROOT		0x00000008U	/* Want/got mnt_root  */
> +#define STATMOUNT_MNT_POINT		0x00000010U	/* Want/got mnt_point */
> +#define STATMOUNT_FS_TYPE		0x00000020U	/* Want/got fs_type */
> +#define STATMOUNT_MNT_NS_ID		0x00000040U	/* Want/got mnt_ns_id */
> +#define STATMOUNT_MNT_OPTS		0x00000080U	/* Want/got mnt_opts */
> +#define STATMOUNT_FS_SUBTYPE		0x00000100U	/* Want/got fs_subtype */
> +#define STATMOUNT_SB_SOURCE		0x00000200U	/* Want/got sb_source */
> +#define STATMOUNT_OPT_ARRAY		0x00000400U	/* Want/got opt_... */
> +#define STATMOUNT_OPT_SEC_ARRAY		0x00000800U	/* Want/got opt_sec... */
> +#define STATMOUNT_SUPPORTED_MASK	0x00001000U	/* Want/got supported mask flags */
> +#define STATMOUNT_MNT_UIDMAP		0x00002000U	/* Want/got uidmap... */
> +#define STATMOUNT_MNT_GIDMAP		0x00004000U	/* Want/got gidmap... */
> +
> +/*
> + * Special @mnt_id values that can be passed to listmount
> + */
> +#define LSMT_ROOT		0xffffffffffffffff	/* root mount */
> +#define LISTMOUNT_REVERSE	(1 << 0) /* List later mounts first */
> +
> +#endif /* _UAPI_LINUX_MOUNT_H */
> diff --git a/tools/include/uapi/linux/nsfs.h b/tools/include/uapi/linux/nsfs.h
> new file mode 100644
> index 000000000000..34127653fd00
> --- /dev/null
> +++ b/tools/include/uapi/linux/nsfs.h
> @@ -0,0 +1,45 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef __LINUX_NSFS_H
> +#define __LINUX_NSFS_H
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +#define NSIO	0xb7
> +
> +/* Returns a file descriptor that refers to an owning user namespace */
> +#define NS_GET_USERNS		_IO(NSIO, 0x1)
> +/* Returns a file descriptor that refers to a parent namespace */
> +#define NS_GET_PARENT		_IO(NSIO, 0x2)
> +/* Returns the type of namespace (CLONE_NEW* value) referred to by
> +   file descriptor */
> +#define NS_GET_NSTYPE		_IO(NSIO, 0x3)
> +/* Get owner UID (in the caller's user namespace) for a user namespace */
> +#define NS_GET_OWNER_UID	_IO(NSIO, 0x4)
> +/* Get the id for a mount namespace */
> +#define NS_GET_MNTNS_ID		_IOR(NSIO, 0x5, __u64)
> +/* Translate pid from target pid namespace into the caller's pid namespace. */
> +#define NS_GET_PID_FROM_PIDNS	_IOR(NSIO, 0x6, int)
> +/* Return thread-group leader id of pid in the callers pid namespace. */
> +#define NS_GET_TGID_FROM_PIDNS	_IOR(NSIO, 0x7, int)
> +/* Translate pid from caller's pid namespace into a target pid namespace. */
> +#define NS_GET_PID_IN_PIDNS	_IOR(NSIO, 0x8, int)
> +/* Return thread-group leader id of pid in the target pid namespace. */
> +#define NS_GET_TGID_IN_PIDNS	_IOR(NSIO, 0x9, int)
> +
> +struct mnt_ns_info {
> +	__u32 size;
> +	__u32 nr_mounts;
> +	__u64 mnt_ns_id;
> +};
> +
> +#define MNT_NS_INFO_SIZE_VER0 16 /* size of first published struct */
> +
> +/* Get information about namespace. */
> +#define NS_MNT_GET_INFO		_IOR(NSIO, 10, struct mnt_ns_info)
> +/* Get next namespace. */
> +#define NS_MNT_GET_NEXT		_IOR(NSIO, 11, struct mnt_ns_info)
> +/* Get previous namespace. */
> +#define NS_MNT_GET_PREV		_IOR(NSIO, 12, struct mnt_ns_info)
> +
> +#endif /* __LINUX_NSFS_H */
> diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
> index 14ee91a41650..19adebfc2620 100644
> --- a/tools/testing/selftests/filesystems/statmount/Makefile
> +++ b/tools/testing/selftests/filesystems/statmount/Makefile
> @@ -1,6 +1,7 @@
>   # SPDX-License-Identifier: GPL-2.0-or-later
>   
> -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)

Yes. :)

> +
>   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
>   
>   include ../../lib.mk
> diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> index a7a5289ddae9..e84d47fadd0b 100644
> --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> @@ -7,6 +7,18 @@
>   #include <linux/mount.h>
>   #include <asm/unistd.h>
>   
> +#ifndef __NR_statmount
> +#if defined(__x86_64__)
> +#define __NR_statmount	457
> +#endif
> +#endif
> +
> +#ifndef __NR_listmount
> +#if defined(__x86_64__)
> +#define __NR_listmount	458
> +#endif
> +#endif

Yes, syscalls are the weak point for this approach, and the above is
reasonable, given the situation, which is: we are not set up to recreate
per-arch syscall tables for kselftests to use. But this does leave the
other big arch out in the cold: arm64.

It's easy to add, though, if and when someone wants it.

> +
>   static inline int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask,
>   			    struct statmount *buf, size_t bufsize,
>   			    unsigned int flags)

Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Amir Goldstein]

Forgot to CC Miklos (now added)

On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 5/7/25 1:42 PM, Amir Goldstein wrote:
> > Copy the required headers files (mount.h, nsfs.h) to the
> > tools include dir and define the statmount/listmount syscalls
> > for x86_64 to decouple dependency with headers_install for the
> > common case.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
...
> > -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> > +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
>
> Yes. :)
>
> > +
> >   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
> >
> >   include ../../lib.mk
> > diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> > index a7a5289ddae9..e84d47fadd0b 100644
> > --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> > +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> > @@ -7,6 +7,18 @@
> >   #include <linux/mount.h>
> >   #include <asm/unistd.h>
> >
> > +#ifndef __NR_statmount
> > +#if defined(__x86_64__)
> > +#define __NR_statmount       457
> > +#endif
> > +#endif
> > +
> > +#ifndef __NR_listmount
> > +#if defined(__x86_64__)
> > +#define __NR_listmount       458
> > +#endif
> > +#endif
>
> Yes, syscalls are the weak point for this approach, and the above is
> reasonable, given the situation, which is: we are not set up to recreate
> per-arch syscall tables for kselftests to use. But this does leave the
> other big arch out in the cold: arm64.
>
> It's easy to add, though, if and when someone wants it.

I have no problem adding || defined(__arm64__)
it's the same syscall numbers anyway.

Or I could do
#if !defined(__alpha__) && !defined(_MIPS_SIM)

but I could not bring myself to do the re-definitions that Christian
added in mount_setattr_test.c for
__NR_mount_setattr, __NR_open_tree, __NR_move_mount

Note that there are stale definitions for __ia64__ in that file
and the stale definition for __NR_move_mount is even wrong ;)

Christian,

How about moving the definitions from mount_setattr_test.c into wrappers.h
and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
case?

Thanks for the review!

Amir.

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[John Hubbard]

On 5/8/25 4:36 AM, Amir Goldstein wrote:
> On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
>> On 5/7/25 1:42 PM, Amir Goldstein wrote:
> ...
>> Yes, syscalls are the weak point for this approach, and the above is
>> reasonable, given the situation, which is: we are not set up to recreate
>> per-arch syscall tables for kselftests to use. But this does leave the
>> other big arch out in the cold: arm64.
>>
>> It's easy to add, though, if and when someone wants it.
> 
> I have no problem adding || defined(__arm64__)
> it's the same syscall numbers anyway.
> 
> Or I could do
> #if !defined(__alpha__) && !defined(_MIPS_SIM)
> 
> but I could not bring myself to do the re-definitions that Christian
> added in mount_setattr_test.c for
> __NR_mount_setattr, __NR_open_tree, __NR_move_mount
> 
> Note that there are stale definitions for __ia64__ in that file
> and the stale definition for __NR_move_mount is even wrong ;)
> 
> Christian,
> 
> How about moving the definitions from mount_setattr_test.c into wrappers.h
> and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
> case?
> 

By the way, is this approach possibly something that the larger kselftests
could use (not in this series, of course)? I recall most of them are doing
something that is x86-only, as well. And so if you have made some observations
about syscall numbers such as "only alpha and mips are different" (?), I
could definitely take that and run with it for the overall kselftests.

thanks,
-- 
John Hubbard

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Amir Goldstein]

On Thu, May 8, 2025 at 9:30 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 5/8/25 4:36 AM, Amir Goldstein wrote:
> > On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
> >> On 5/7/25 1:42 PM, Amir Goldstein wrote:
> > ...
> >> Yes, syscalls are the weak point for this approach, and the above is
> >> reasonable, given the situation, which is: we are not set up to recreate
> >> per-arch syscall tables for kselftests to use. But this does leave the
> >> other big arch out in the cold: arm64.
> >>
> >> It's easy to add, though, if and when someone wants it.
> >
> > I have no problem adding || defined(__arm64__)
> > it's the same syscall numbers anyway.
> >
> > Or I could do
> > #if !defined(__alpha__) && !defined(_MIPS_SIM)
> >
> > but I could not bring myself to do the re-definitions that Christian
> > added in mount_setattr_test.c for
> > __NR_mount_setattr, __NR_open_tree, __NR_move_mount
> >
> > Note that there are stale definitions for __ia64__ in that file
> > and the stale definition for __NR_move_mount is even wrong ;)
> >
> > Christian,
> >
> > How about moving the definitions from mount_setattr_test.c into wrappers.h
> > and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
> > case?
> >
>
> By the way, is this approach possibly something that the larger kselftests
> could use (not in this series, of course)? I recall most of them are doing
> something that is x86-only, as well. And so if you have made some observations
> about syscall numbers such as "only alpha and mips are different" (?), I
> could definitely take that and run with it for the overall kselftests.

I don't think this is generally correct.
It is correct for the syscall numbers in this file.

Thanks,
Amir.

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Christian Brauner]

On Thu, May 08, 2025 at 01:36:09PM +0200, Amir Goldstein wrote:
> Forgot to CC Miklos (now added)
> 
> On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
> >
> > On 5/7/25 1:42 PM, Amir Goldstein wrote:
> > > Copy the required headers files (mount.h, nsfs.h) to the
> > > tools include dir and define the statmount/listmount syscalls
> > > for x86_64 to decouple dependency with headers_install for the
> > > common case.
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> ...
> > > -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> > > +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> >
> > Yes. :)
> >
> > > +
> > >   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
> > >
> > >   include ../../lib.mk
> > > diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > index a7a5289ddae9..e84d47fadd0b 100644
> > > --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> > > +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > @@ -7,6 +7,18 @@
> > >   #include <linux/mount.h>
> > >   #include <asm/unistd.h>
> > >
> > > +#ifndef __NR_statmount
> > > +#if defined(__x86_64__)
> > > +#define __NR_statmount       457
> > > +#endif
> > > +#endif
> > > +
> > > +#ifndef __NR_listmount
> > > +#if defined(__x86_64__)
> > > +#define __NR_listmount       458
> > > +#endif
> > > +#endif
> >
> > Yes, syscalls are the weak point for this approach, and the above is
> > reasonable, given the situation, which is: we are not set up to recreate
> > per-arch syscall tables for kselftests to use. But this does leave the
> > other big arch out in the cold: arm64.
> >
> > It's easy to add, though, if and when someone wants it.
> 
> I have no problem adding || defined(__arm64__)
> it's the same syscall numbers anyway.
> 
> Or I could do
> #if !defined(__alpha__) && !defined(_MIPS_SIM)
> 
> but I could not bring myself to do the re-definitions that Christian
> added in mount_setattr_test.c for
> __NR_mount_setattr, __NR_open_tree, __NR_move_mount
> 
> Note that there are stale definitions for __ia64__ in that file
> and the stale definition for __NR_move_mount is even wrong ;)
> 
> Christian,
> 
> How about moving the definitions from mount_setattr_test.c into wrappers.h
> and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
> case?
> 
> Thanks for the review!

For new system calls this covers all arches and is what I usually use:

#ifndef __NR_open_tree
        #if defined __alpha__
                #define __NR_open_tree 538
        #elif defined _MIPS_SIM
                #if _MIPS_SIM == _MIPS_SIM_ABI32        /* o32 */
                        #define __NR_open_tree 4428
                #endif
                #if _MIPS_SIM == _MIPS_SIM_NABI32       /* n32 */
                        #define __NR_open_tree 6428
                #endif
                #if _MIPS_SIM == _MIPS_SIM_ABI64        /* n64 */
                        #define __NR_open_tree 5428
                #endif
        #elif defined __ia64__
                #define __NR_open_tree (428 + 1024)
        #else
                #define __NR_open_tree 428
        #endif
#endif

where the ia64 stuff can obviously be removed now.

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Amir Goldstein]

On Fri, May 9, 2025 at 12:57 PM Christian Brauner <brauner@kernel.org> wrote:
>
> On Thu, May 08, 2025 at 01:36:09PM +0200, Amir Goldstein wrote:
> > Forgot to CC Miklos (now added)
> >
> > On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
> > >
> > > On 5/7/25 1:42 PM, Amir Goldstein wrote:
> > > > Copy the required headers files (mount.h, nsfs.h) to the
> > > > tools include dir and define the statmount/listmount syscalls
> > > > for x86_64 to decouple dependency with headers_install for the
> > > > common case.
> > > >
> > > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > > ---
> > ...
> > > > -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> > > > +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> > >
> > > Yes. :)
> > >
> > > > +
> > > >   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
> > > >
> > > >   include ../../lib.mk
> > > > diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > index a7a5289ddae9..e84d47fadd0b 100644
> > > > --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > @@ -7,6 +7,18 @@
> > > >   #include <linux/mount.h>
> > > >   #include <asm/unistd.h>
> > > >
> > > > +#ifndef __NR_statmount
> > > > +#if defined(__x86_64__)
> > > > +#define __NR_statmount       457
> > > > +#endif
> > > > +#endif
> > > > +
> > > > +#ifndef __NR_listmount
> > > > +#if defined(__x86_64__)
> > > > +#define __NR_listmount       458
> > > > +#endif
> > > > +#endif
> > >
> > > Yes, syscalls are the weak point for this approach, and the above is
> > > reasonable, given the situation, which is: we are not set up to recreate
> > > per-arch syscall tables for kselftests to use. But this does leave the
> > > other big arch out in the cold: arm64.
> > >
> > > It's easy to add, though, if and when someone wants it.
> >
> > I have no problem adding || defined(__arm64__)
> > it's the same syscall numbers anyway.
> >
> > Or I could do
> > #if !defined(__alpha__) && !defined(_MIPS_SIM)
> >
> > but I could not bring myself to do the re-definitions that Christian
> > added in mount_setattr_test.c for
> > __NR_mount_setattr, __NR_open_tree, __NR_move_mount
> >
> > Note that there are stale definitions for __ia64__ in that file
> > and the stale definition for __NR_move_mount is even wrong ;)
> >
> > Christian,
> >
> > How about moving the definitions from mount_setattr_test.c into wrappers.h
> > and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
> > case?
> >
> > Thanks for the review!
>
> For new system calls this covers all arches and is what I usually use:
>
> #ifndef __NR_open_tree
>         #if defined __alpha__
>                 #define __NR_open_tree 538
>         #elif defined _MIPS_SIM
>                 #if _MIPS_SIM == _MIPS_SIM_ABI32        /* o32 */
>                         #define __NR_open_tree 4428
>                 #endif
>                 #if _MIPS_SIM == _MIPS_SIM_NABI32       /* n32 */
>                         #define __NR_open_tree 6428
>                 #endif
>                 #if _MIPS_SIM == _MIPS_SIM_ABI64        /* n64 */
>                         #define __NR_open_tree 5428
>                 #endif
>         #elif defined __ia64__
>                 #define __NR_open_tree (428 + 1024)
>         #else
>                 #define __NR_open_tree 428
>         #endif
> #endif
>
> where the ia64 stuff can obviously be removed now.

Well, the question is, wrt this patch, do you require that listmount/statmount
syscall numbers be defined for all archs or is this acceptable to you:

+#ifndef __NR_statmount
+#if defined(__x86_64__) || defined(__arm64__)
+#define __NR_statmount 457
+#endif
+#endif
+
+#ifndef __NR_listmount
+#if defined(__x86_64__) || defined(__arm64__)
+#define __NR_listmount 458
+#endif
+#endif

Or the opt-out variant of
#if !defined(__alpha__) && !defined(_MIPS_SIM)

Please let me know what you prefer and I will post a new patch set version with
the fanotify test inside user ns.

Thanks,
Amir.

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[Amir Goldstein]

On Fri, May 9, 2025 at 12:57 PM Christian Brauner <brauner@kernel.org> wrote:
>
> On Thu, May 08, 2025 at 01:36:09PM +0200, Amir Goldstein wrote:
> > Forgot to CC Miklos (now added)
> >
> > On Thu, May 8, 2025 at 9:31 AM John Hubbard <jhubbard@nvidia.com> wrote:
> > >
> > > On 5/7/25 1:42 PM, Amir Goldstein wrote:
> > > > Copy the required headers files (mount.h, nsfs.h) to the
> > > > tools include dir and define the statmount/listmount syscalls
> > > > for x86_64 to decouple dependency with headers_install for the
> > > > common case.
> > > >
> > > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > > ---
> > ...
> > > > -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> > > > +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> > >
> > > Yes. :)
> > >
> > > > +
> > > >   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
> > > >
> > > >   include ../../lib.mk
> > > > diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > index a7a5289ddae9..e84d47fadd0b 100644
> > > > --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> > > > @@ -7,6 +7,18 @@
> > > >   #include <linux/mount.h>
> > > >   #include <asm/unistd.h>
> > > >
> > > > +#ifndef __NR_statmount
> > > > +#if defined(__x86_64__)
> > > > +#define __NR_statmount       457
> > > > +#endif
> > > > +#endif
> > > > +
> > > > +#ifndef __NR_listmount
> > > > +#if defined(__x86_64__)
> > > > +#define __NR_listmount       458
> > > > +#endif
> > > > +#endif
> > >
> > > Yes, syscalls are the weak point for this approach, and the above is
> > > reasonable, given the situation, which is: we are not set up to recreate
> > > per-arch syscall tables for kselftests to use. But this does leave the
> > > other big arch out in the cold: arm64.
> > >
> > > It's easy to add, though, if and when someone wants it.
> >
> > I have no problem adding || defined(__arm64__)
> > it's the same syscall numbers anyway.
> >
> > Or I could do
> > #if !defined(__alpha__) && !defined(_MIPS_SIM)
> >
> > but I could not bring myself to do the re-definitions that Christian
> > added in mount_setattr_test.c for
> > __NR_mount_setattr, __NR_open_tree, __NR_move_mount
> >
> > Note that there are stale definitions for __ia64__ in that file
> > and the stale definition for __NR_move_mount is even wrong ;)
> >
> > Christian,
> >
> > How about moving the definitions from mount_setattr_test.c into wrappers.h
> > and leaving only the common !defined(__alpha__) && !defined(_MIPS_SIM)
> > case?
> >
> > Thanks for the review!
>
> For new system calls this covers all arches and is what I usually use:
>
> #ifndef __NR_open_tree
>         #if defined __alpha__
>                 #define __NR_open_tree 538
>         #elif defined _MIPS_SIM
>                 #if _MIPS_SIM == _MIPS_SIM_ABI32        /* o32 */
>                         #define __NR_open_tree 4428
>                 #endif
>                 #if _MIPS_SIM == _MIPS_SIM_NABI32       /* n32 */
>                         #define __NR_open_tree 6428
>                 #endif
>                 #if _MIPS_SIM == _MIPS_SIM_ABI64        /* n64 */
>                         #define __NR_open_tree 5428
>                 #endif
>         #elif defined __ia64__
>                 #define __NR_open_tree (428 + 1024)
>         #else
>                 #define __NR_open_tree 428
>         #endif
> #endif
>
> where the ia64 stuff can obviously be removed now.

All right.
Sent v2 with all those defs for listmount/statmount.

Thanks,
Amir.

Re: [PATCH 2/5] selftests/fs/statmount: build with tools include dir

[John Hubbard]

On 5/7/25 1:42 PM, Amir Goldstein wrote:
> Copy the required headers files (mount.h, nsfs.h) to the
> tools include dir and define the statmount/listmount syscalls
> for x86_64 to decouple dependency with headers_install for the
> common case.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   tools/include/uapi/linux/mount.h              | 235 ++++++++++++++++++
>   tools/include/uapi/linux/nsfs.h               |  45 ++++
>   .../selftests/filesystems/statmount/Makefile  |   3 +-
>   .../filesystems/statmount/statmount.h         |  12 +
>   4 files changed, 294 insertions(+), 1 deletion(-)
>   create mode 100644 tools/include/uapi/linux/mount.h
>   create mode 100644 tools/include/uapi/linux/nsfs.h
> 

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,
-- 
John Hubbard

> diff --git a/tools/include/uapi/linux/mount.h b/tools/include/uapi/linux/mount.h
> new file mode 100644
> index 000000000000..7fa67c2031a5
> --- /dev/null
> +++ b/tools/include/uapi/linux/mount.h
> @@ -0,0 +1,235 @@
> +#ifndef _UAPI_LINUX_MOUNT_H
> +#define _UAPI_LINUX_MOUNT_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * These are the fs-independent mount-flags: up to 32 flags are supported
> + *
> + * Usage of these is restricted within the kernel to core mount(2) code and
> + * callers of sys_mount() only.  Filesystems should be using the SB_*
> + * equivalent instead.
> + */
> +#define MS_RDONLY	 1	/* Mount read-only */
> +#define MS_NOSUID	 2	/* Ignore suid and sgid bits */
> +#define MS_NODEV	 4	/* Disallow access to device special files */
> +#define MS_NOEXEC	 8	/* Disallow program execution */
> +#define MS_SYNCHRONOUS	16	/* Writes are synced at once */
> +#define MS_REMOUNT	32	/* Alter flags of a mounted FS */
> +#define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
> +#define MS_DIRSYNC	128	/* Directory modifications are synchronous */
> +#define MS_NOSYMFOLLOW	256	/* Do not follow symlinks */
> +#define MS_NOATIME	1024	/* Do not update access times. */
> +#define MS_NODIRATIME	2048	/* Do not update directory access times */
> +#define MS_BIND		4096
> +#define MS_MOVE		8192
> +#define MS_REC		16384
> +#define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
> +				   MS_VERBOSE is deprecated. */
> +#define MS_SILENT	32768
> +#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
> +#define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
> +#define MS_PRIVATE	(1<<18)	/* change to private */
> +#define MS_SLAVE	(1<<19)	/* change to slave */
> +#define MS_SHARED	(1<<20)	/* change to shared */
> +#define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
> +#define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
> +#define MS_I_VERSION	(1<<23) /* Update inode I_version field */
> +#define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
> +#define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
> +
> +/* These sb flags are internal to the kernel */
> +#define MS_SUBMOUNT     (1<<26)
> +#define MS_NOREMOTELOCK	(1<<27)
> +#define MS_NOSEC	(1<<28)
> +#define MS_BORN		(1<<29)
> +#define MS_ACTIVE	(1<<30)
> +#define MS_NOUSER	(1<<31)
> +
> +/*
> + * Superblock flags that can be altered by MS_REMOUNT
> + */
> +#define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION|\
> +			 MS_LAZYTIME)
> +
> +/*
> + * Old magic mount flag and mask
> + */
> +#define MS_MGC_VAL 0xC0ED0000
> +#define MS_MGC_MSK 0xffff0000
> +
> +/*
> + * open_tree() flags.
> + */
> +#define OPEN_TREE_CLONE		1		/* Clone the target tree and attach the clone */
> +#define OPEN_TREE_CLOEXEC	O_CLOEXEC	/* Close the file on execve() */
> +
> +/*
> + * move_mount() flags.
> + */
> +#define MOVE_MOUNT_F_SYMLINKS		0x00000001 /* Follow symlinks on from path */
> +#define MOVE_MOUNT_F_AUTOMOUNTS		0x00000002 /* Follow automounts on from path */
> +#define MOVE_MOUNT_F_EMPTY_PATH		0x00000004 /* Empty from path permitted */
> +#define MOVE_MOUNT_T_SYMLINKS		0x00000010 /* Follow symlinks on to path */
> +#define MOVE_MOUNT_T_AUTOMOUNTS		0x00000020 /* Follow automounts on to path */
> +#define MOVE_MOUNT_T_EMPTY_PATH		0x00000040 /* Empty to path permitted */
> +#define MOVE_MOUNT_SET_GROUP		0x00000100 /* Set sharing group instead */
> +#define MOVE_MOUNT_BENEATH		0x00000200 /* Mount beneath top mount */
> +#define MOVE_MOUNT__MASK		0x00000377
> +
> +/*
> + * fsopen() flags.
> + */
> +#define FSOPEN_CLOEXEC		0x00000001
> +
> +/*
> + * fspick() flags.
> + */
> +#define FSPICK_CLOEXEC		0x00000001
> +#define FSPICK_SYMLINK_NOFOLLOW	0x00000002
> +#define FSPICK_NO_AUTOMOUNT	0x00000004
> +#define FSPICK_EMPTY_PATH	0x00000008
> +
> +/*
> + * The type of fsconfig() call made.
> + */
> +enum fsconfig_command {
> +	FSCONFIG_SET_FLAG	= 0,	/* Set parameter, supplying no value */
> +	FSCONFIG_SET_STRING	= 1,	/* Set parameter, supplying a string value */
> +	FSCONFIG_SET_BINARY	= 2,	/* Set parameter, supplying a binary blob value */
> +	FSCONFIG_SET_PATH	= 3,	/* Set parameter, supplying an object by path */
> +	FSCONFIG_SET_PATH_EMPTY	= 4,	/* Set parameter, supplying an object by (empty) path */
> +	FSCONFIG_SET_FD		= 5,	/* Set parameter, supplying an object by fd */
> +	FSCONFIG_CMD_CREATE	= 6,	/* Create new or reuse existing superblock */
> +	FSCONFIG_CMD_RECONFIGURE = 7,	/* Invoke superblock reconfiguration */
> +	FSCONFIG_CMD_CREATE_EXCL = 8,	/* Create new superblock, fail if reusing existing superblock */
> +};
> +
> +/*
> + * fsmount() flags.
> + */
> +#define FSMOUNT_CLOEXEC		0x00000001
> +
> +/*
> + * Mount attributes.
> + */
> +#define MOUNT_ATTR_RDONLY	0x00000001 /* Mount read-only */
> +#define MOUNT_ATTR_NOSUID	0x00000002 /* Ignore suid and sgid bits */
> +#define MOUNT_ATTR_NODEV	0x00000004 /* Disallow access to device special files */
> +#define MOUNT_ATTR_NOEXEC	0x00000008 /* Disallow program execution */
> +#define MOUNT_ATTR__ATIME	0x00000070 /* Setting on how atime should be updated */
> +#define MOUNT_ATTR_RELATIME	0x00000000 /* - Update atime relative to mtime/ctime. */
> +#define MOUNT_ATTR_NOATIME	0x00000010 /* - Do not update access times. */
> +#define MOUNT_ATTR_STRICTATIME	0x00000020 /* - Always perform atime updates */
> +#define MOUNT_ATTR_NODIRATIME	0x00000080 /* Do not update directory access times */
> +#define MOUNT_ATTR_IDMAP	0x00100000 /* Idmap mount to @userns_fd in struct mount_attr. */
> +#define MOUNT_ATTR_NOSYMFOLLOW	0x00200000 /* Do not follow symlinks */
> +
> +/*
> + * mount_setattr()
> + */
> +struct mount_attr {
> +	__u64 attr_set;
> +	__u64 attr_clr;
> +	__u64 propagation;
> +	__u64 userns_fd;
> +};
> +
> +/* List of all mount_attr versions. */
> +#define MOUNT_ATTR_SIZE_VER0	32 /* sizeof first published struct */
> +
> +
> +/*
> + * Structure for getting mount/superblock/filesystem info with statmount(2).
> + *
> + * The interface is similar to statx(2): individual fields or groups can be
> + * selected with the @mask argument of statmount().  Kernel will set the @mask
> + * field according to the supported fields.
> + *
> + * If string fields are selected, then the caller needs to pass a buffer that
> + * has space after the fixed part of the structure.  Nul terminated strings are
> + * copied there and offsets relative to @str are stored in the relevant fields.
> + * If the buffer is too small, then EOVERFLOW is returned.  The actually used
> + * size is returned in @size.
> + */
> +struct statmount {
> +	__u32 size;		/* Total size, including strings */
> +	__u32 mnt_opts;		/* [str] Options (comma separated, escaped) */
> +	__u64 mask;		/* What results were written */
> +	__u32 sb_dev_major;	/* Device ID */
> +	__u32 sb_dev_minor;
> +	__u64 sb_magic;		/* ..._SUPER_MAGIC */
> +	__u32 sb_flags;		/* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
> +	__u32 fs_type;		/* [str] Filesystem type */
> +	__u64 mnt_id;		/* Unique ID of mount */
> +	__u64 mnt_parent_id;	/* Unique ID of parent (for root == mnt_id) */
> +	__u32 mnt_id_old;	/* Reused IDs used in proc/.../mountinfo */
> +	__u32 mnt_parent_id_old;
> +	__u64 mnt_attr;		/* MOUNT_ATTR_... */
> +	__u64 mnt_propagation;	/* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
> +	__u64 mnt_peer_group;	/* ID of shared peer group */
> +	__u64 mnt_master;	/* Mount receives propagation from this ID */
> +	__u64 propagate_from;	/* Propagation from in current namespace */
> +	__u32 mnt_root;		/* [str] Root of mount relative to root of fs */
> +	__u32 mnt_point;	/* [str] Mountpoint relative to current root */
> +	__u64 mnt_ns_id;	/* ID of the mount namespace */
> +	__u32 fs_subtype;	/* [str] Subtype of fs_type (if any) */
> +	__u32 sb_source;	/* [str] Source string of the mount */
> +	__u32 opt_num;		/* Number of fs options */
> +	__u32 opt_array;	/* [str] Array of nul terminated fs options */
> +	__u32 opt_sec_num;	/* Number of security options */
> +	__u32 opt_sec_array;	/* [str] Array of nul terminated security options */
> +	__u64 supported_mask;	/* Mask flags that this kernel supports */
> +	__u32 mnt_uidmap_num;	/* Number of uid mappings */
> +	__u32 mnt_uidmap;	/* [str] Array of uid mappings (as seen from callers namespace) */
> +	__u32 mnt_gidmap_num;	/* Number of gid mappings */
> +	__u32 mnt_gidmap;	/* [str] Array of gid mappings (as seen from callers namespace) */
> +	__u64 __spare2[43];
> +	char str[];		/* Variable size part containing strings */
> +};
> +
> +/*
> + * Structure for passing mount ID and miscellaneous parameters to statmount(2)
> + * and listmount(2).
> + *
> + * For statmount(2) @param represents the request mask.
> + * For listmount(2) @param represents the last listed mount id (or zero).
> + */
> +struct mnt_id_req {
> +	__u32 size;
> +	__u32 spare;
> +	__u64 mnt_id;
> +	__u64 param;
> +	__u64 mnt_ns_id;
> +};
> +
> +/* List of all mnt_id_req versions. */
> +#define MNT_ID_REQ_SIZE_VER0	24 /* sizeof first published struct */
> +#define MNT_ID_REQ_SIZE_VER1	32 /* sizeof second published struct */
> +
> +/*
> + * @mask bits for statmount(2)
> + */
> +#define STATMOUNT_SB_BASIC		0x00000001U     /* Want/got sb_... */
> +#define STATMOUNT_MNT_BASIC		0x00000002U	/* Want/got mnt_... */
> +#define STATMOUNT_PROPAGATE_FROM	0x00000004U	/* Want/got propagate_from */
> +#define STATMOUNT_MNT_ROOT		0x00000008U	/* Want/got mnt_root  */
> +#define STATMOUNT_MNT_POINT		0x00000010U	/* Want/got mnt_point */
> +#define STATMOUNT_FS_TYPE		0x00000020U	/* Want/got fs_type */
> +#define STATMOUNT_MNT_NS_ID		0x00000040U	/* Want/got mnt_ns_id */
> +#define STATMOUNT_MNT_OPTS		0x00000080U	/* Want/got mnt_opts */
> +#define STATMOUNT_FS_SUBTYPE		0x00000100U	/* Want/got fs_subtype */
> +#define STATMOUNT_SB_SOURCE		0x00000200U	/* Want/got sb_source */
> +#define STATMOUNT_OPT_ARRAY		0x00000400U	/* Want/got opt_... */
> +#define STATMOUNT_OPT_SEC_ARRAY		0x00000800U	/* Want/got opt_sec... */
> +#define STATMOUNT_SUPPORTED_MASK	0x00001000U	/* Want/got supported mask flags */
> +#define STATMOUNT_MNT_UIDMAP		0x00002000U	/* Want/got uidmap... */
> +#define STATMOUNT_MNT_GIDMAP		0x00004000U	/* Want/got gidmap... */
> +
> +/*
> + * Special @mnt_id values that can be passed to listmount
> + */
> +#define LSMT_ROOT		0xffffffffffffffff	/* root mount */
> +#define LISTMOUNT_REVERSE	(1 << 0) /* List later mounts first */
> +
> +#endif /* _UAPI_LINUX_MOUNT_H */
> diff --git a/tools/include/uapi/linux/nsfs.h b/tools/include/uapi/linux/nsfs.h
> new file mode 100644
> index 000000000000..34127653fd00
> --- /dev/null
> +++ b/tools/include/uapi/linux/nsfs.h
> @@ -0,0 +1,45 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef __LINUX_NSFS_H
> +#define __LINUX_NSFS_H
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +#define NSIO	0xb7
> +
> +/* Returns a file descriptor that refers to an owning user namespace */
> +#define NS_GET_USERNS		_IO(NSIO, 0x1)
> +/* Returns a file descriptor that refers to a parent namespace */
> +#define NS_GET_PARENT		_IO(NSIO, 0x2)
> +/* Returns the type of namespace (CLONE_NEW* value) referred to by
> +   file descriptor */
> +#define NS_GET_NSTYPE		_IO(NSIO, 0x3)
> +/* Get owner UID (in the caller's user namespace) for a user namespace */
> +#define NS_GET_OWNER_UID	_IO(NSIO, 0x4)
> +/* Get the id for a mount namespace */
> +#define NS_GET_MNTNS_ID		_IOR(NSIO, 0x5, __u64)
> +/* Translate pid from target pid namespace into the caller's pid namespace. */
> +#define NS_GET_PID_FROM_PIDNS	_IOR(NSIO, 0x6, int)
> +/* Return thread-group leader id of pid in the callers pid namespace. */
> +#define NS_GET_TGID_FROM_PIDNS	_IOR(NSIO, 0x7, int)
> +/* Translate pid from caller's pid namespace into a target pid namespace. */
> +#define NS_GET_PID_IN_PIDNS	_IOR(NSIO, 0x8, int)
> +/* Return thread-group leader id of pid in the target pid namespace. */
> +#define NS_GET_TGID_IN_PIDNS	_IOR(NSIO, 0x9, int)
> +
> +struct mnt_ns_info {
> +	__u32 size;
> +	__u32 nr_mounts;
> +	__u64 mnt_ns_id;
> +};
> +
> +#define MNT_NS_INFO_SIZE_VER0 16 /* size of first published struct */
> +
> +/* Get information about namespace. */
> +#define NS_MNT_GET_INFO		_IOR(NSIO, 10, struct mnt_ns_info)
> +/* Get next namespace. */
> +#define NS_MNT_GET_NEXT		_IOR(NSIO, 11, struct mnt_ns_info)
> +/* Get previous namespace. */
> +#define NS_MNT_GET_PREV		_IOR(NSIO, 12, struct mnt_ns_info)
> +
> +#endif /* __LINUX_NSFS_H */
> diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
> index 14ee91a41650..19adebfc2620 100644
> --- a/tools/testing/selftests/filesystems/statmount/Makefile
> +++ b/tools/testing/selftests/filesystems/statmount/Makefile
> @@ -1,6 +1,7 @@
>   # SPDX-License-Identifier: GPL-2.0-or-later
>   
> -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> +
>   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
>   
>   include ../../lib.mk
> diff --git a/tools/testing/selftests/filesystems/statmount/statmount.h b/tools/testing/selftests/filesystems/statmount/statmount.h
> index a7a5289ddae9..e84d47fadd0b 100644
> --- a/tools/testing/selftests/filesystems/statmount/statmount.h
> +++ b/tools/testing/selftests/filesystems/statmount/statmount.h
> @@ -7,6 +7,18 @@
>   #include <linux/mount.h>
>   #include <asm/unistd.h>
>   
> +#ifndef __NR_statmount
> +#if defined(__x86_64__)
> +#define __NR_statmount	457
> +#endif
> +#endif
> +
> +#ifndef __NR_listmount
> +#if defined(__x86_64__)
> +#define __NR_listmount	458
> +#endif
> +#endif
> +
>   static inline int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask,
>   			    struct statmount *buf, size_t bufsize,
>   			    unsigned int flags)

[PATCH 3/5] selftests/fs/mount-notify: build with tools include dir

[Amir Goldstein]

Copy the fanotify uapi header files to the tools include dir
and define __kernel_fsid_t to decouple dependency with headers_install
and then remove the redundant re-definitions of fanotify macros.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tools/include/uapi/linux/fanotify.h           | 274 ++++++++++++++++++
 .../filesystems/mount-notify/Makefile         |   3 +-
 .../mount-notify/mount-notify_test.c          |  25 +-
 3 files changed, 282 insertions(+), 20 deletions(-)
 create mode 100644 tools/include/uapi/linux/fanotify.h

diff --git a/tools/include/uapi/linux/fanotify.h b/tools/include/uapi/linux/fanotify.h
new file mode 100644
index 000000000000..e710967c7c26
--- /dev/null
+++ b/tools/include/uapi/linux/fanotify.h
@@ -0,0 +1,274 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_FANOTIFY_H
+#define _UAPI_LINUX_FANOTIFY_H
+
+#include <linux/types.h>
+
+/* the following events that user-space can register for */
+#define FAN_ACCESS		0x00000001	/* File was accessed */
+#define FAN_MODIFY		0x00000002	/* File was modified */
+#define FAN_ATTRIB		0x00000004	/* Metadata changed */
+#define FAN_CLOSE_WRITE		0x00000008	/* Writable file closed */
+#define FAN_CLOSE_NOWRITE	0x00000010	/* Unwritable file closed */
+#define FAN_OPEN		0x00000020	/* File was opened */
+#define FAN_MOVED_FROM		0x00000040	/* File was moved from X */
+#define FAN_MOVED_TO		0x00000080	/* File was moved to Y */
+#define FAN_CREATE		0x00000100	/* Subfile was created */
+#define FAN_DELETE		0x00000200	/* Subfile was deleted */
+#define FAN_DELETE_SELF		0x00000400	/* Self was deleted */
+#define FAN_MOVE_SELF		0x00000800	/* Self was moved */
+#define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
+
+#define FAN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
+#define FAN_FS_ERROR		0x00008000	/* Filesystem error */
+
+#define FAN_OPEN_PERM		0x00010000	/* File open in perm check */
+#define FAN_ACCESS_PERM		0x00020000	/* File accessed in perm check */
+#define FAN_OPEN_EXEC_PERM	0x00040000	/* File open/exec in perm check */
+/* #define FAN_DIR_MODIFY	0x00080000 */	/* Deprecated (reserved) */
+
+#define FAN_PRE_ACCESS		0x00100000	/* Pre-content access hook */
+#define FAN_MNT_ATTACH		0x01000000	/* Mount was attached */
+#define FAN_MNT_DETACH		0x02000000	/* Mount was detached */
+
+#define FAN_EVENT_ON_CHILD	0x08000000	/* Interested in child events */
+
+#define FAN_RENAME		0x10000000	/* File was renamed */
+
+#define FAN_ONDIR		0x40000000	/* Event occurred against dir */
+
+/* helper events */
+#define FAN_CLOSE		(FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
+#define FAN_MOVE		(FAN_MOVED_FROM | FAN_MOVED_TO) /* moves */
+
+/* flags used for fanotify_init() */
+#define FAN_CLOEXEC		0x00000001
+#define FAN_NONBLOCK		0x00000002
+
+/* These are NOT bitwise flags.  Both bits are used together.  */
+#define FAN_CLASS_NOTIF		0x00000000
+#define FAN_CLASS_CONTENT	0x00000004
+#define FAN_CLASS_PRE_CONTENT	0x00000008
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_CLASS_BITS	(FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
+				 FAN_CLASS_PRE_CONTENT)
+
+#define FAN_UNLIMITED_QUEUE	0x00000010
+#define FAN_UNLIMITED_MARKS	0x00000020
+#define FAN_ENABLE_AUDIT	0x00000040
+
+/* Flags to determine fanotify event format */
+#define FAN_REPORT_PIDFD	0x00000080	/* Report pidfd for event->pid */
+#define FAN_REPORT_TID		0x00000100	/* event->pid is thread id */
+#define FAN_REPORT_FID		0x00000200	/* Report unique file id */
+#define FAN_REPORT_DIR_FID	0x00000400	/* Report unique directory id */
+#define FAN_REPORT_NAME		0x00000800	/* Report events with name */
+#define FAN_REPORT_TARGET_FID	0x00001000	/* Report dirent target id  */
+#define FAN_REPORT_FD_ERROR	0x00002000	/* event->fd can report error */
+#define FAN_REPORT_MNT		0x00004000	/* Report mount events */
+
+/* Convenience macro - FAN_REPORT_NAME requires FAN_REPORT_DIR_FID */
+#define FAN_REPORT_DFID_NAME	(FAN_REPORT_DIR_FID | FAN_REPORT_NAME)
+/* Convenience macro - FAN_REPORT_TARGET_FID requires all other FID flags */
+#define FAN_REPORT_DFID_NAME_TARGET (FAN_REPORT_DFID_NAME | \
+				     FAN_REPORT_FID | FAN_REPORT_TARGET_FID)
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_INIT_FLAGS	(FAN_CLOEXEC | FAN_NONBLOCK | \
+				 FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\
+				 FAN_UNLIMITED_MARKS)
+
+/* flags used for fanotify_modify_mark() */
+#define FAN_MARK_ADD		0x00000001
+#define FAN_MARK_REMOVE		0x00000002
+#define FAN_MARK_DONT_FOLLOW	0x00000004
+#define FAN_MARK_ONLYDIR	0x00000008
+/* FAN_MARK_MOUNT is		0x00000010 */
+#define FAN_MARK_IGNORED_MASK	0x00000020
+#define FAN_MARK_IGNORED_SURV_MODIFY	0x00000040
+#define FAN_MARK_FLUSH		0x00000080
+/* FAN_MARK_FILESYSTEM is	0x00000100 */
+#define FAN_MARK_EVICTABLE	0x00000200
+/* This bit is mutually exclusive with FAN_MARK_IGNORED_MASK bit */
+#define FAN_MARK_IGNORE		0x00000400
+
+/* These are NOT bitwise flags.  Both bits can be used togther.  */
+#define FAN_MARK_INODE		0x00000000
+#define FAN_MARK_MOUNT		0x00000010
+#define FAN_MARK_FILESYSTEM	0x00000100
+#define FAN_MARK_MNTNS		0x00000110
+
+/*
+ * Convenience macro - FAN_MARK_IGNORE requires FAN_MARK_IGNORED_SURV_MODIFY
+ * for non-inode mark types.
+ */
+#define FAN_MARK_IGNORE_SURV	(FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY)
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_MARK_FLAGS	(FAN_MARK_ADD |\
+				 FAN_MARK_REMOVE |\
+				 FAN_MARK_DONT_FOLLOW |\
+				 FAN_MARK_ONLYDIR |\
+				 FAN_MARK_MOUNT |\
+				 FAN_MARK_IGNORED_MASK |\
+				 FAN_MARK_IGNORED_SURV_MODIFY |\
+				 FAN_MARK_FLUSH)
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_EVENTS (FAN_ACCESS |\
+			FAN_MODIFY |\
+			FAN_CLOSE |\
+			FAN_OPEN)
+
+/*
+ * All events which require a permission response from userspace
+ */
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
+			     FAN_ACCESS_PERM)
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
+#define FAN_ALL_OUTGOING_EVENTS	(FAN_ALL_EVENTS |\
+				 FAN_ALL_PERM_EVENTS |\
+				 FAN_Q_OVERFLOW)
+
+#define FANOTIFY_METADATA_VERSION	3
+
+struct fanotify_event_metadata {
+	__u32 event_len;
+	__u8 vers;
+	__u8 reserved;
+	__u16 metadata_len;
+	__aligned_u64 mask;
+	__s32 fd;
+	__s32 pid;
+};
+
+#define FAN_EVENT_INFO_TYPE_FID		1
+#define FAN_EVENT_INFO_TYPE_DFID_NAME	2
+#define FAN_EVENT_INFO_TYPE_DFID	3
+#define FAN_EVENT_INFO_TYPE_PIDFD	4
+#define FAN_EVENT_INFO_TYPE_ERROR	5
+#define FAN_EVENT_INFO_TYPE_RANGE	6
+#define FAN_EVENT_INFO_TYPE_MNT		7
+
+/* Special info types for FAN_RENAME */
+#define FAN_EVENT_INFO_TYPE_OLD_DFID_NAME	10
+/* Reserved for FAN_EVENT_INFO_TYPE_OLD_DFID	11 */
+#define FAN_EVENT_INFO_TYPE_NEW_DFID_NAME	12
+/* Reserved for FAN_EVENT_INFO_TYPE_NEW_DFID	13 */
+
+/* Variable length info record following event metadata */
+struct fanotify_event_info_header {
+	__u8 info_type;
+	__u8 pad;
+	__u16 len;
+};
+
+/*
+ * Unique file identifier info record.
+ * This structure is used for records of types FAN_EVENT_INFO_TYPE_FID,
+ * FAN_EVENT_INFO_TYPE_DFID and FAN_EVENT_INFO_TYPE_DFID_NAME.
+ * For FAN_EVENT_INFO_TYPE_DFID_NAME there is additionally a null terminated
+ * name immediately after the file handle.
+ */
+struct fanotify_event_info_fid {
+	struct fanotify_event_info_header hdr;
+	__kernel_fsid_t fsid;
+	/*
+	 * Following is an opaque struct file_handle that can be passed as
+	 * an argument to open_by_handle_at(2).
+	 */
+	unsigned char handle[];
+};
+
+/*
+ * This structure is used for info records of type FAN_EVENT_INFO_TYPE_PIDFD.
+ * It holds a pidfd for the pid that was responsible for generating an event.
+ */
+struct fanotify_event_info_pidfd {
+	struct fanotify_event_info_header hdr;
+	__s32 pidfd;
+};
+
+struct fanotify_event_info_error {
+	struct fanotify_event_info_header hdr;
+	__s32 error;
+	__u32 error_count;
+};
+
+struct fanotify_event_info_range {
+	struct fanotify_event_info_header hdr;
+	__u32 pad;
+	__u64 offset;
+	__u64 count;
+};
+
+struct fanotify_event_info_mnt {
+	struct fanotify_event_info_header hdr;
+	__u64 mnt_id;
+};
+
+/*
+ * User space may need to record additional information about its decision.
+ * The extra information type records what kind of information is included.
+ * The default is none. We also define an extra information buffer whose
+ * size is determined by the extra information type.
+ *
+ * If the information type is Audit Rule, then the information following
+ * is the rule number that triggered the user space decision that
+ * requires auditing.
+ */
+
+#define FAN_RESPONSE_INFO_NONE		0
+#define FAN_RESPONSE_INFO_AUDIT_RULE	1
+
+struct fanotify_response {
+	__s32 fd;
+	__u32 response;
+};
+
+struct fanotify_response_info_header {
+	__u8 type;
+	__u8 pad;
+	__u16 len;
+};
+
+struct fanotify_response_info_audit_rule {
+	struct fanotify_response_info_header hdr;
+	__u32 rule_number;
+	__u32 subj_trust;
+	__u32 obj_trust;
+};
+
+/* Legit userspace responses to a _PERM event */
+#define FAN_ALLOW	0x01
+#define FAN_DENY	0x02
+/* errno other than EPERM can specified in upper byte of deny response */
+#define FAN_ERRNO_BITS	8
+#define FAN_ERRNO_SHIFT (32 - FAN_ERRNO_BITS)
+#define FAN_ERRNO_MASK	((1 << FAN_ERRNO_BITS) - 1)
+#define FAN_DENY_ERRNO(err) \
+	(FAN_DENY | ((((__u32)(err)) & FAN_ERRNO_MASK) << FAN_ERRNO_SHIFT))
+
+#define FAN_AUDIT	0x10	/* Bitmask to create audit record for result */
+#define FAN_INFO	0x20	/* Bitmask to indicate additional information */
+
+/* No fd set in event */
+#define FAN_NOFD	-1
+#define FAN_NOPIDFD	FAN_NOFD
+#define FAN_EPIDFD	-2
+
+/* Helper functions to deal with fanotify_event_metadata buffers */
+#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
+
+#define FAN_EVENT_NEXT(meta, len) ((len) -= (meta)->event_len, \
+				   (struct fanotify_event_metadata*)(((char *)(meta)) + \
+				   (meta)->event_len))
+
+#define FAN_EVENT_OK(meta, len)	((long)(len) >= (long)FAN_EVENT_METADATA_LEN && \
+				(long)(meta)->event_len >= (long)FAN_EVENT_METADATA_LEN && \
+				(long)(meta)->event_len <= (long)(len))
+
+#endif /* _UAPI_LINUX_FANOTIFY_H */
diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile
index 10be0227b5ae..41ebfe558a0a 100644
--- a/tools/testing/selftests/filesystems/mount-notify/Makefile
+++ b/tools/testing/selftests/filesystems/mount-notify/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
+CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
+
 TEST_GEN_PROGS := mount-notify_test
 
 include ../../lib.mk
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
index 59a71f22fb11..4f0f325379b5 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
@@ -8,33 +8,20 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/mount.h>
-#include <linux/fanotify.h>
 #include <unistd.h>
-#include <sys/fanotify.h>
 #include <sys/syscall.h>
 
 #include "../../kselftest_harness.h"
 #include "../statmount/statmount.h"
 
-#ifndef FAN_MNT_ATTACH
-struct fanotify_event_info_mnt {
-	struct fanotify_event_info_header hdr;
-	__u64 mnt_id;
-};
-#define FAN_MNT_ATTACH 0x01000000 /* Mount was attached */
-#endif
-
-#ifndef FAN_MNT_DETACH
-#define FAN_MNT_DETACH 0x02000000 /* Mount was detached */
+// Needed for linux/fanotify.h
+#ifndef __kernel_fsid_t
+typedef struct {
+	int	val[2];
+} __kernel_fsid_t;
 #endif
 
-#ifndef FAN_REPORT_MNT
-#define FAN_REPORT_MNT 0x00004000 /* Report mount events */
-#endif
-
-#ifndef FAN_MARK_MNTNS
-#define FAN_MARK_MNTNS 0x00000110
-#endif
+#include <sys/fanotify.h>
 
 static uint64_t get_mnt_id(struct __test_metadata *const _metadata,
 			   const char *path)
-- 
2.34.1

Re: [PATCH 3/5] selftests/fs/mount-notify: build with tools include dir

[John Hubbard]

On 5/7/25 1:43 PM, Amir Goldstein wrote:
> Copy the fanotify uapi header files to the tools include dir
> and define __kernel_fsid_t to decouple dependency with headers_install
> and then remove the redundant re-definitions of fanotify macros.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   tools/include/uapi/linux/fanotify.h           | 274 ++++++++++++++++++
>   .../filesystems/mount-notify/Makefile         |   3 +-
>   .../mount-notify/mount-notify_test.c          |  25 +-
>   3 files changed, 282 insertions(+), 20 deletions(-)
>   create mode 100644 tools/include/uapi/linux/fanotify.h
> 
> diff --git a/tools/include/uapi/linux/fanotify.h b/tools/include/uapi/linux/fanotify.h
> new file mode 100644
> index 000000000000..e710967c7c26
> --- /dev/null
> +++ b/tools/include/uapi/linux/fanotify.h
> @@ -0,0 +1,274 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _UAPI_LINUX_FANOTIFY_H
> +#define _UAPI_LINUX_FANOTIFY_H
> +
> +#include <linux/types.h>
> +
> +/* the following events that user-space can register for */
> +#define FAN_ACCESS		0x00000001	/* File was accessed */
> +#define FAN_MODIFY		0x00000002	/* File was modified */
> +#define FAN_ATTRIB		0x00000004	/* Metadata changed */
> +#define FAN_CLOSE_WRITE		0x00000008	/* Writable file closed */
> +#define FAN_CLOSE_NOWRITE	0x00000010	/* Unwritable file closed */
> +#define FAN_OPEN		0x00000020	/* File was opened */
> +#define FAN_MOVED_FROM		0x00000040	/* File was moved from X */
> +#define FAN_MOVED_TO		0x00000080	/* File was moved to Y */
> +#define FAN_CREATE		0x00000100	/* Subfile was created */
> +#define FAN_DELETE		0x00000200	/* Subfile was deleted */
> +#define FAN_DELETE_SELF		0x00000400	/* Self was deleted */
> +#define FAN_MOVE_SELF		0x00000800	/* Self was moved */
> +#define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
> +
> +#define FAN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
> +#define FAN_FS_ERROR		0x00008000	/* Filesystem error */
> +
> +#define FAN_OPEN_PERM		0x00010000	/* File open in perm check */
> +#define FAN_ACCESS_PERM		0x00020000	/* File accessed in perm check */
> +#define FAN_OPEN_EXEC_PERM	0x00040000	/* File open/exec in perm check */
> +/* #define FAN_DIR_MODIFY	0x00080000 */	/* Deprecated (reserved) */
> +
> +#define FAN_PRE_ACCESS		0x00100000	/* Pre-content access hook */
> +#define FAN_MNT_ATTACH		0x01000000	/* Mount was attached */
> +#define FAN_MNT_DETACH		0x02000000	/* Mount was detached */
> +
> +#define FAN_EVENT_ON_CHILD	0x08000000	/* Interested in child events */
> +
> +#define FAN_RENAME		0x10000000	/* File was renamed */
> +
> +#define FAN_ONDIR		0x40000000	/* Event occurred against dir */
> +
> +/* helper events */
> +#define FAN_CLOSE		(FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
> +#define FAN_MOVE		(FAN_MOVED_FROM | FAN_MOVED_TO) /* moves */
> +
> +/* flags used for fanotify_init() */
> +#define FAN_CLOEXEC		0x00000001
> +#define FAN_NONBLOCK		0x00000002
> +
> +/* These are NOT bitwise flags.  Both bits are used together.  */
> +#define FAN_CLASS_NOTIF		0x00000000
> +#define FAN_CLASS_CONTENT	0x00000004
> +#define FAN_CLASS_PRE_CONTENT	0x00000008
> +
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_CLASS_BITS	(FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
> +				 FAN_CLASS_PRE_CONTENT)
> +
> +#define FAN_UNLIMITED_QUEUE	0x00000010
> +#define FAN_UNLIMITED_MARKS	0x00000020
> +#define FAN_ENABLE_AUDIT	0x00000040
> +
> +/* Flags to determine fanotify event format */
> +#define FAN_REPORT_PIDFD	0x00000080	/* Report pidfd for event->pid */
> +#define FAN_REPORT_TID		0x00000100	/* event->pid is thread id */
> +#define FAN_REPORT_FID		0x00000200	/* Report unique file id */
> +#define FAN_REPORT_DIR_FID	0x00000400	/* Report unique directory id */
> +#define FAN_REPORT_NAME		0x00000800	/* Report events with name */
> +#define FAN_REPORT_TARGET_FID	0x00001000	/* Report dirent target id  */
> +#define FAN_REPORT_FD_ERROR	0x00002000	/* event->fd can report error */
> +#define FAN_REPORT_MNT		0x00004000	/* Report mount events */
> +
> +/* Convenience macro - FAN_REPORT_NAME requires FAN_REPORT_DIR_FID */
> +#define FAN_REPORT_DFID_NAME	(FAN_REPORT_DIR_FID | FAN_REPORT_NAME)
> +/* Convenience macro - FAN_REPORT_TARGET_FID requires all other FID flags */
> +#define FAN_REPORT_DFID_NAME_TARGET (FAN_REPORT_DFID_NAME | \
> +				     FAN_REPORT_FID | FAN_REPORT_TARGET_FID)
> +
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_INIT_FLAGS	(FAN_CLOEXEC | FAN_NONBLOCK | \
> +				 FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\
> +				 FAN_UNLIMITED_MARKS)
> +
> +/* flags used for fanotify_modify_mark() */
> +#define FAN_MARK_ADD		0x00000001
> +#define FAN_MARK_REMOVE		0x00000002
> +#define FAN_MARK_DONT_FOLLOW	0x00000004
> +#define FAN_MARK_ONLYDIR	0x00000008
> +/* FAN_MARK_MOUNT is		0x00000010 */
> +#define FAN_MARK_IGNORED_MASK	0x00000020
> +#define FAN_MARK_IGNORED_SURV_MODIFY	0x00000040
> +#define FAN_MARK_FLUSH		0x00000080
> +/* FAN_MARK_FILESYSTEM is	0x00000100 */
> +#define FAN_MARK_EVICTABLE	0x00000200
> +/* This bit is mutually exclusive with FAN_MARK_IGNORED_MASK bit */
> +#define FAN_MARK_IGNORE		0x00000400
> +
> +/* These are NOT bitwise flags.  Both bits can be used togther.  */
> +#define FAN_MARK_INODE		0x00000000
> +#define FAN_MARK_MOUNT		0x00000010
> +#define FAN_MARK_FILESYSTEM	0x00000100
> +#define FAN_MARK_MNTNS		0x00000110
> +
> +/*
> + * Convenience macro - FAN_MARK_IGNORE requires FAN_MARK_IGNORED_SURV_MODIFY
> + * for non-inode mark types.
> + */
> +#define FAN_MARK_IGNORE_SURV	(FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY)
> +
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_MARK_FLAGS	(FAN_MARK_ADD |\
> +				 FAN_MARK_REMOVE |\
> +				 FAN_MARK_DONT_FOLLOW |\
> +				 FAN_MARK_ONLYDIR |\
> +				 FAN_MARK_MOUNT |\
> +				 FAN_MARK_IGNORED_MASK |\
> +				 FAN_MARK_IGNORED_SURV_MODIFY |\
> +				 FAN_MARK_FLUSH)
> +
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_EVENTS (FAN_ACCESS |\
> +			FAN_MODIFY |\
> +			FAN_CLOSE |\
> +			FAN_OPEN)
> +
> +/*
> + * All events which require a permission response from userspace
> + */
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
> +			     FAN_ACCESS_PERM)
> +
> +/* Deprecated - do not use this in programs and do not add new flags here! */
> +#define FAN_ALL_OUTGOING_EVENTS	(FAN_ALL_EVENTS |\
> +				 FAN_ALL_PERM_EVENTS |\
> +				 FAN_Q_OVERFLOW)
> +
> +#define FANOTIFY_METADATA_VERSION	3
> +
> +struct fanotify_event_metadata {
> +	__u32 event_len;
> +	__u8 vers;
> +	__u8 reserved;
> +	__u16 metadata_len;
> +	__aligned_u64 mask;
> +	__s32 fd;
> +	__s32 pid;
> +};
> +
> +#define FAN_EVENT_INFO_TYPE_FID		1
> +#define FAN_EVENT_INFO_TYPE_DFID_NAME	2
> +#define FAN_EVENT_INFO_TYPE_DFID	3
> +#define FAN_EVENT_INFO_TYPE_PIDFD	4
> +#define FAN_EVENT_INFO_TYPE_ERROR	5
> +#define FAN_EVENT_INFO_TYPE_RANGE	6
> +#define FAN_EVENT_INFO_TYPE_MNT		7
> +
> +/* Special info types for FAN_RENAME */
> +#define FAN_EVENT_INFO_TYPE_OLD_DFID_NAME	10
> +/* Reserved for FAN_EVENT_INFO_TYPE_OLD_DFID	11 */
> +#define FAN_EVENT_INFO_TYPE_NEW_DFID_NAME	12
> +/* Reserved for FAN_EVENT_INFO_TYPE_NEW_DFID	13 */
> +
> +/* Variable length info record following event metadata */
> +struct fanotify_event_info_header {
> +	__u8 info_type;
> +	__u8 pad;
> +	__u16 len;
> +};
> +
> +/*
> + * Unique file identifier info record.
> + * This structure is used for records of types FAN_EVENT_INFO_TYPE_FID,
> + * FAN_EVENT_INFO_TYPE_DFID and FAN_EVENT_INFO_TYPE_DFID_NAME.
> + * For FAN_EVENT_INFO_TYPE_DFID_NAME there is additionally a null terminated
> + * name immediately after the file handle.
> + */
> +struct fanotify_event_info_fid {
> +	struct fanotify_event_info_header hdr;
> +	__kernel_fsid_t fsid;
> +	/*
> +	 * Following is an opaque struct file_handle that can be passed as
> +	 * an argument to open_by_handle_at(2).
> +	 */
> +	unsigned char handle[];
> +};
> +
> +/*
> + * This structure is used for info records of type FAN_EVENT_INFO_TYPE_PIDFD.
> + * It holds a pidfd for the pid that was responsible for generating an event.
> + */
> +struct fanotify_event_info_pidfd {
> +	struct fanotify_event_info_header hdr;
> +	__s32 pidfd;
> +};
> +
> +struct fanotify_event_info_error {
> +	struct fanotify_event_info_header hdr;
> +	__s32 error;
> +	__u32 error_count;
> +};
> +
> +struct fanotify_event_info_range {
> +	struct fanotify_event_info_header hdr;
> +	__u32 pad;
> +	__u64 offset;
> +	__u64 count;
> +};
> +
> +struct fanotify_event_info_mnt {
> +	struct fanotify_event_info_header hdr;
> +	__u64 mnt_id;
> +};
> +
> +/*
> + * User space may need to record additional information about its decision.
> + * The extra information type records what kind of information is included.
> + * The default is none. We also define an extra information buffer whose
> + * size is determined by the extra information type.
> + *
> + * If the information type is Audit Rule, then the information following
> + * is the rule number that triggered the user space decision that
> + * requires auditing.
> + */
> +
> +#define FAN_RESPONSE_INFO_NONE		0
> +#define FAN_RESPONSE_INFO_AUDIT_RULE	1
> +
> +struct fanotify_response {
> +	__s32 fd;
> +	__u32 response;
> +};
> +
> +struct fanotify_response_info_header {
> +	__u8 type;
> +	__u8 pad;
> +	__u16 len;
> +};
> +
> +struct fanotify_response_info_audit_rule {
> +	struct fanotify_response_info_header hdr;
> +	__u32 rule_number;
> +	__u32 subj_trust;
> +	__u32 obj_trust;
> +};
> +
> +/* Legit userspace responses to a _PERM event */
> +#define FAN_ALLOW	0x01
> +#define FAN_DENY	0x02
> +/* errno other than EPERM can specified in upper byte of deny response */
> +#define FAN_ERRNO_BITS	8
> +#define FAN_ERRNO_SHIFT (32 - FAN_ERRNO_BITS)
> +#define FAN_ERRNO_MASK	((1 << FAN_ERRNO_BITS) - 1)
> +#define FAN_DENY_ERRNO(err) \
> +	(FAN_DENY | ((((__u32)(err)) & FAN_ERRNO_MASK) << FAN_ERRNO_SHIFT))
> +
> +#define FAN_AUDIT	0x10	/* Bitmask to create audit record for result */
> +#define FAN_INFO	0x20	/* Bitmask to indicate additional information */
> +
> +/* No fd set in event */
> +#define FAN_NOFD	-1
> +#define FAN_NOPIDFD	FAN_NOFD
> +#define FAN_EPIDFD	-2
> +
> +/* Helper functions to deal with fanotify_event_metadata buffers */
> +#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
> +
> +#define FAN_EVENT_NEXT(meta, len) ((len) -= (meta)->event_len, \
> +				   (struct fanotify_event_metadata*)(((char *)(meta)) + \
> +				   (meta)->event_len))
> +
> +#define FAN_EVENT_OK(meta, len)	((long)(len) >= (long)FAN_EVENT_METADATA_LEN && \
> +				(long)(meta)->event_len >= (long)FAN_EVENT_METADATA_LEN && \
> +				(long)(meta)->event_len <= (long)(len))
> +
> +#endif /* _UAPI_LINUX_FANOTIFY_H */
> diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile
> index 10be0227b5ae..41ebfe558a0a 100644
> --- a/tools/testing/selftests/filesystems/mount-notify/Makefile
> +++ b/tools/testing/selftests/filesystems/mount-notify/Makefile
> @@ -1,6 +1,7 @@
>   # SPDX-License-Identifier: GPL-2.0-or-later
>   
> -CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
> +CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> +
>   TEST_GEN_PROGS := mount-notify_test
>   
>   include ../../lib.mk
> diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> index 59a71f22fb11..4f0f325379b5 100644
> --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> @@ -8,33 +8,20 @@
>   #include <string.h>
>   #include <sys/stat.h>
>   #include <sys/mount.h>
> -#include <linux/fanotify.h>
>   #include <unistd.h>
> -#include <sys/fanotify.h>
>   #include <sys/syscall.h>
>   
>   #include "../../kselftest_harness.h"
>   #include "../statmount/statmount.h"
>   
> -#ifndef FAN_MNT_ATTACH
> -struct fanotify_event_info_mnt {
> -	struct fanotify_event_info_header hdr;
> -	__u64 mnt_id;
> -};
> -#define FAN_MNT_ATTACH 0x01000000 /* Mount was attached */
> -#endif
> -
> -#ifndef FAN_MNT_DETACH
> -#define FAN_MNT_DETACH 0x02000000 /* Mount was detached */
> +// Needed for linux/fanotify.h

Is the comment accurate? Below, we are include sys/fanotify.h, not
linux/fanotify.h


> +#ifndef __kernel_fsid_t
> +typedef struct {
> +	int	val[2];
> +} __kernel_fsid_t;
>   #endif
>   
> -#ifndef FAN_REPORT_MNT
> -#define FAN_REPORT_MNT 0x00004000 /* Report mount events */
> -#endif
> -
> -#ifndef FAN_MARK_MNTNS
> -#define FAN_MARK_MNTNS 0x00000110
> -#endif
> +#include <sys/fanotify.h>

Are you sure that you're including your newly added fanotify.h? Because
it looks to me like you might be including your local installed version,
instead. I don't see how it can include

     tools/include/uapi/linux/fanotify.h

...with the above invocation.

>   
>   static uint64_t get_mnt_id(struct __test_metadata *const _metadata,
>   			   const char *path)

thanks,
-- 
John Hubbard

Re: [PATCH 3/5] selftests/fs/mount-notify: build with tools include dir

[Amir Goldstein]

On Thu, May 8, 2025 at 9:38 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 5/7/25 1:43 PM, Amir Goldstein wrote:
> > Copy the fanotify uapi header files to the tools include dir
> > and define __kernel_fsid_t to decouple dependency with headers_install
> > and then remove the redundant re-definitions of fanotify macros.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
...
> > diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > index 59a71f22fb11..4f0f325379b5 100644
> > --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > @@ -8,33 +8,20 @@
> >   #include <string.h>
> >   #include <sys/stat.h>
> >   #include <sys/mount.h>
> > -#include <linux/fanotify.h>
> >   #include <unistd.h>
> > -#include <sys/fanotify.h>
> >   #include <sys/syscall.h>
> >
> >   #include "../../kselftest_harness.h"
> >   #include "../statmount/statmount.h"
> >
> > -#ifndef FAN_MNT_ATTACH
> > -struct fanotify_event_info_mnt {
> > -     struct fanotify_event_info_header hdr;
> > -     __u64 mnt_id;
> > -};
> > -#define FAN_MNT_ATTACH 0x01000000 /* Mount was attached */
> > -#endif
> > -
> > -#ifndef FAN_MNT_DETACH
> > -#define FAN_MNT_DETACH 0x02000000 /* Mount was detached */
> > +// Needed for linux/fanotify.h
>
> Is the comment accurate? Below, we are include sys/fanotify.h, not
> linux/fanotify.h
>

Yes, it is accurate.
sys/fanotify.h includes linux/fanotify.h
linux/fanotify.h needs __kernel_fsid_t
I considered copying posix_types.h, but it seemed wrong
and I think __kernel_fsid_t definition is the same on all archs anyway.

>
> > +#ifndef __kernel_fsid_t
> > +typedef struct {
> > +     int     val[2];
> > +} __kernel_fsid_t;
> >   #endif
> >
> > -#ifndef FAN_REPORT_MNT
> > -#define FAN_REPORT_MNT 0x00004000 /* Report mount events */
> > -#endif
> > -
> > -#ifndef FAN_MARK_MNTNS
> > -#define FAN_MARK_MNTNS 0x00000110
> > -#endif
> > +#include <sys/fanotify.h>
>
> Are you sure that you're including your newly added fanotify.h? Because
> it looks to me like you might be including your local installed version,
> instead. I don't see how it can include
>
>      tools/include/uapi/linux/fanotify.h
>
> ...with the above invocation.
>

Yes, it works.

My local installed linux/fanotify.h does not include FAN_MARK_MNTNS
it is only available in my source and tools include dirs.

Does the fact that sys/fanotify.h includes linux/fanotify.h explains what
didn't make sense to you?

Thanks,
Amir.

Re: [PATCH 3/5] selftests/fs/mount-notify: build with tools include dir

[John Hubbard]

On 5/8/25 4:53 AM, Amir Goldstein wrote:
> On Thu, May 8, 2025 at 9:38 AM John Hubbard <jhubbard@nvidia.com> wrote:
>> On 5/7/25 1:43 PM, Amir Goldstein wrote:
...
>> Are you sure that you're including your newly added fanotify.h? Because
>> it looks to me like you might be including your local installed version,
>> instead. I don't see how it can include
>>
>>      tools/include/uapi/linux/fanotify.h
>>
>> ...with the above invocation.
>>
> 
> Yes, it works.
> 
> My local installed linux/fanotify.h does not include FAN_MARK_MNTNS
> it is only available in my source and tools include dirs.
> 
> Does the fact that sys/fanotify.h includes linux/fanotify.h explains what
> didn't make sense to you?
> 

aha yes, that solves the mystery for me.

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,
-- 
John Hubbard

[PATCH 4/5] selftests/filesystems: create get_unique_mnt_id() helper

[Amir Goldstein]

Add helper to utils and use it in mount-notify and statmount tests.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 .../filesystems/mount-notify/Makefile         |  3 ++
 .../mount-notify/mount-notify_test.c          | 13 ++-------
 .../selftests/filesystems/statmount/Makefile  |  3 ++
 .../filesystems/statmount/statmount_test_ns.c | 28 +++----------------
 tools/testing/selftests/filesystems/utils.c   | 20 +++++++++++++
 tools/testing/selftests/filesystems/utils.h   |  2 ++
 6 files changed, 34 insertions(+), 35 deletions(-)

diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile
index 41ebfe558a0a..55a2e5399e8a 100644
--- a/tools/testing/selftests/filesystems/mount-notify/Makefile
+++ b/tools/testing/selftests/filesystems/mount-notify/Makefile
@@ -1,7 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
+LDLIBS += -lcap
 
 TEST_GEN_PROGS := mount-notify_test
 
 include ../../lib.mk
+
+$(OUTPUT)/mount-notify_test: ../utils.c
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
index 4f0f325379b5..63ce708d93ed 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
@@ -13,6 +13,7 @@
 
 #include "../../kselftest_harness.h"
 #include "../statmount/statmount.h"
+#include "../utils.h"
 
 // Needed for linux/fanotify.h
 #ifndef __kernel_fsid_t
@@ -23,16 +24,6 @@ typedef struct {
 
 #include <sys/fanotify.h>
 
-static uint64_t get_mnt_id(struct __test_metadata *const _metadata,
-			   const char *path)
-{
-	struct statx sx;
-
-	ASSERT_EQ(statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx), 0);
-	ASSERT_TRUE(!!(sx.stx_mask & STATX_MNT_ID_UNIQUE));
-	return sx.stx_mnt_id;
-}
-
 static const char root_mntpoint_templ[] = "/tmp/mount-notify_test_root.XXXXXX";
 
 static const int mark_cmds[] = {
@@ -81,7 +72,7 @@ FIXTURE_SETUP(fanotify)
 
 	ASSERT_EQ(mkdir("b", 0700), 0);
 
-	self->root_id = get_mnt_id(_metadata, "/");
+	self->root_id = get_unique_mnt_id("/");
 	ASSERT_NE(self->root_id, 0);
 
 	for (i = 0; i < NUM_FAN_FDS; i++) {
diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
index 19adebfc2620..8e354fe99b44 100644
--- a/tools/testing/selftests/filesystems/statmount/Makefile
+++ b/tools/testing/selftests/filesystems/statmount/Makefile
@@ -1,7 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
+LDLIBS += -lcap
 
 TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
 
 include ../../lib.mk
+
+$(OUTPUT)/statmount_test_ns: ../utils.c
diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
index 70cb0c8b21cf..375a52101d08 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
+++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
@@ -14,6 +14,7 @@
 #include <linux/stat.h>
 
 #include "statmount.h"
+#include "../utils.h"
 #include "../../kselftest.h"
 
 #define NSID_PASS 0
@@ -78,27 +79,6 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
 	return NSID_PASS;
 }
 
-static int get_mnt_id(const char *path, uint64_t *mnt_id)
-{
-	struct statx sx;
-	int ret;
-
-	ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
-	if (ret == -1) {
-		ksft_print_msg("retrieving unique mount ID for %s: %s\n", path,
-			       strerror(errno));
-		return NSID_ERROR;
-	}
-
-	if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
-		ksft_print_msg("no unique mount ID available for %s\n", path);
-		return NSID_ERROR;
-	}
-
-	*mnt_id = sx.stx_mnt_id;
-	return NSID_PASS;
-}
-
 static int write_file(const char *path, const char *val)
 {
 	int fd = open(path, O_WRONLY);
@@ -174,9 +154,9 @@ static int _test_statmount_mnt_ns_id(void)
 	if (ret != NSID_PASS)
 		return ret;
 
-	ret = get_mnt_id("/", &root_id);
-	if (ret != NSID_PASS)
-		return ret;
+	root_id = get_unique_mnt_id("/");
+	if (!root_id)
+		return NSID_ERROR;
 
 	ret = statmount(root_id, 0, STATMOUNT_MNT_NS_ID, &sm, sizeof(sm), 0);
 	if (ret == -1) {
diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
index e553c89c5b19..9b5419e6f28d 100644
--- a/tools/testing/selftests/filesystems/utils.c
+++ b/tools/testing/selftests/filesystems/utils.c
@@ -499,3 +499,23 @@ int cap_down(cap_value_t down)
 	cap_free(caps);
 	return fret;
 }
+
+uint64_t get_unique_mnt_id(const char *path)
+{
+	struct statx sx;
+	int ret;
+
+	ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
+	if (ret == -1) {
+		syserror("retrieving unique mount ID for %s: %s\n", path,
+			 strerror(errno));
+		return 0;
+	}
+
+	if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
+		syserror("no unique mount ID available for %s\n", path);
+		return 0;
+	}
+
+	return sx.stx_mnt_id;
+}
diff --git a/tools/testing/selftests/filesystems/utils.h b/tools/testing/selftests/filesystems/utils.h
index 7f1df2a3e94c..d9cf145b321a 100644
--- a/tools/testing/selftests/filesystems/utils.h
+++ b/tools/testing/selftests/filesystems/utils.h
@@ -42,4 +42,6 @@ static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)
 	return true;
 }
 
+extern uint64_t get_unique_mnt_id(const char *path);
+
 #endif /* __IDMAP_UTILS_H */
-- 
2.34.1

Re: [PATCH 4/5] selftests/filesystems: create get_unique_mnt_id() helper

[John Hubbard]

On 5/7/25 1:43 PM, Amir Goldstein wrote:
> Add helper to utils and use it in mount-notify and statmount tests.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   .../filesystems/mount-notify/Makefile         |  3 ++
>   .../mount-notify/mount-notify_test.c          | 13 ++-------
>   .../selftests/filesystems/statmount/Makefile  |  3 ++
>   .../filesystems/statmount/statmount_test_ns.c | 28 +++----------------
>   tools/testing/selftests/filesystems/utils.c   | 20 +++++++++++++
>   tools/testing/selftests/filesystems/utils.h   |  2 ++
>   6 files changed, 34 insertions(+), 35 deletions(-)
> 
> diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile
> index 41ebfe558a0a..55a2e5399e8a 100644
> --- a/tools/testing/selftests/filesystems/mount-notify/Makefile
> +++ b/tools/testing/selftests/filesystems/mount-notify/Makefile
> @@ -1,7 +1,10 @@
>   # SPDX-License-Identifier: GPL-2.0-or-later
>   
>   CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> +LDLIBS += -lcap

This addition of -lcap goes completely unmentioned in the commit log.
I'm guessing you are fixing things up to build, so this definitely
deserves an explanation there.

>   
>   TEST_GEN_PROGS := mount-notify_test
>   
>   include ../../lib.mk
> +
> +$(OUTPUT)/mount-notify_test: ../utils.c
> diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> index 4f0f325379b5..63ce708d93ed 100644
> --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> @@ -13,6 +13,7 @@
>   
>   #include "../../kselftest_harness.h"
>   #include "../statmount/statmount.h"
> +#include "../utils.h"
>   
>   // Needed for linux/fanotify.h
>   #ifndef __kernel_fsid_t
> @@ -23,16 +24,6 @@ typedef struct {
>   
>   #include <sys/fanotify.h>
>   
> -static uint64_t get_mnt_id(struct __test_metadata *const _metadata,
> -			   const char *path)
> -{
> -	struct statx sx;
> -
> -	ASSERT_EQ(statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx), 0);
> -	ASSERT_TRUE(!!(sx.stx_mask & STATX_MNT_ID_UNIQUE));
> -	return sx.stx_mnt_id;
> -}
> -
>   static const char root_mntpoint_templ[] = "/tmp/mount-notify_test_root.XXXXXX";
>   
>   static const int mark_cmds[] = {
> @@ -81,7 +72,7 @@ FIXTURE_SETUP(fanotify)
>   
>   	ASSERT_EQ(mkdir("b", 0700), 0);
>   
> -	self->root_id = get_mnt_id(_metadata, "/");
> +	self->root_id = get_unique_mnt_id("/");
>   	ASSERT_NE(self->root_id, 0);
>   
>   	for (i = 0; i < NUM_FAN_FDS; i++) {
> diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
> index 19adebfc2620..8e354fe99b44 100644
> --- a/tools/testing/selftests/filesystems/statmount/Makefile
> +++ b/tools/testing/selftests/filesystems/statmount/Makefile
> @@ -1,7 +1,10 @@
>   # SPDX-License-Identifier: GPL-2.0-or-later
>   
>   CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> +LDLIBS += -lcap

And here.

>   
>   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
>   
>   include ../../lib.mk
> +
> +$(OUTPUT)/statmount_test_ns: ../utils.c

This is surprising: a new Makefile target, without removing an old one.
And it's still listed in TEST_GEN_PROGS...

Why did you feel the need to add this target?

thanks,
-- 
John Hubbard

> diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> index 70cb0c8b21cf..375a52101d08 100644
> --- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> +++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> @@ -14,6 +14,7 @@
>   #include <linux/stat.h>
>   
>   #include "statmount.h"
> +#include "../utils.h"
>   #include "../../kselftest.h"
>   
>   #define NSID_PASS 0
> @@ -78,27 +79,6 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
>   	return NSID_PASS;
>   }
>   
> -static int get_mnt_id(const char *path, uint64_t *mnt_id)
> -{
> -	struct statx sx;
> -	int ret;
> -
> -	ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
> -	if (ret == -1) {
> -		ksft_print_msg("retrieving unique mount ID for %s: %s\n", path,
> -			       strerror(errno));
> -		return NSID_ERROR;
> -	}
> -
> -	if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
> -		ksft_print_msg("no unique mount ID available for %s\n", path);
> -		return NSID_ERROR;
> -	}
> -
> -	*mnt_id = sx.stx_mnt_id;
> -	return NSID_PASS;
> -}
> -
>   static int write_file(const char *path, const char *val)
>   {
>   	int fd = open(path, O_WRONLY);
> @@ -174,9 +154,9 @@ static int _test_statmount_mnt_ns_id(void)
>   	if (ret != NSID_PASS)
>   		return ret;
>   
> -	ret = get_mnt_id("/", &root_id);
> -	if (ret != NSID_PASS)
> -		return ret;
> +	root_id = get_unique_mnt_id("/");
> +	if (!root_id)
> +		return NSID_ERROR;
>   
>   	ret = statmount(root_id, 0, STATMOUNT_MNT_NS_ID, &sm, sizeof(sm), 0);
>   	if (ret == -1) {
> diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
> index e553c89c5b19..9b5419e6f28d 100644
> --- a/tools/testing/selftests/filesystems/utils.c
> +++ b/tools/testing/selftests/filesystems/utils.c
> @@ -499,3 +499,23 @@ int cap_down(cap_value_t down)
>   	cap_free(caps);
>   	return fret;
>   }
> +
> +uint64_t get_unique_mnt_id(const char *path)
> +{
> +	struct statx sx;
> +	int ret;
> +
> +	ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
> +	if (ret == -1) {
> +		syserror("retrieving unique mount ID for %s: %s\n", path,
> +			 strerror(errno));
> +		return 0;
> +	}
> +
> +	if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
> +		syserror("no unique mount ID available for %s\n", path);
> +		return 0;
> +	}
> +
> +	return sx.stx_mnt_id;
> +}
> diff --git a/tools/testing/selftests/filesystems/utils.h b/tools/testing/selftests/filesystems/utils.h
> index 7f1df2a3e94c..d9cf145b321a 100644
> --- a/tools/testing/selftests/filesystems/utils.h
> +++ b/tools/testing/selftests/filesystems/utils.h
> @@ -42,4 +42,6 @@ static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)
>   	return true;
>   }
>   
> +extern uint64_t get_unique_mnt_id(const char *path);
> +
>   #endif /* __IDMAP_UTILS_H */

Re: [PATCH 4/5] selftests/filesystems: create get_unique_mnt_id() helper

[Amir Goldstein]

On Thu, May 8, 2025 at 9:43 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 5/7/25 1:43 PM, Amir Goldstein wrote:
> > Add helper to utils and use it in mount-notify and statmount tests.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> >   .../filesystems/mount-notify/Makefile         |  3 ++
> >   .../mount-notify/mount-notify_test.c          | 13 ++-------
> >   .../selftests/filesystems/statmount/Makefile  |  3 ++
> >   .../filesystems/statmount/statmount_test_ns.c | 28 +++----------------
> >   tools/testing/selftests/filesystems/utils.c   | 20 +++++++++++++
> >   tools/testing/selftests/filesystems/utils.h   |  2 ++
> >   6 files changed, 34 insertions(+), 35 deletions(-)
> >
> > diff --git a/tools/testing/selftests/filesystems/mount-notify/Makefile b/tools/testing/selftests/filesystems/mount-notify/Makefile
> > index 41ebfe558a0a..55a2e5399e8a 100644
> > --- a/tools/testing/selftests/filesystems/mount-notify/Makefile
> > +++ b/tools/testing/selftests/filesystems/mount-notify/Makefile
> > @@ -1,7 +1,10 @@
> >   # SPDX-License-Identifier: GPL-2.0-or-later
> >
> >   CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> > +LDLIBS += -lcap
>
> This addition of -lcap goes completely unmentioned in the commit log.
> I'm guessing you are fixing things up to build, so this definitely
> deserves an explanation there.
>

This is needed because we are linking with utils.c code.
See below.
I guess we could have built a filesystems selftests utils library,
but that seems like an operkill?

> >
> >   TEST_GEN_PROGS := mount-notify_test
> >
> >   include ../../lib.mk
> > +
> > +$(OUTPUT)/mount-notify_test: ../utils.c
> > diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > index 4f0f325379b5..63ce708d93ed 100644
> > --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
> > @@ -13,6 +13,7 @@
> >
> >   #include "../../kselftest_harness.h"
> >   #include "../statmount/statmount.h"
> > +#include "../utils.h"
> >
> >   // Needed for linux/fanotify.h
> >   #ifndef __kernel_fsid_t
> > @@ -23,16 +24,6 @@ typedef struct {
> >
> >   #include <sys/fanotify.h>
> >
> > -static uint64_t get_mnt_id(struct __test_metadata *const _metadata,
> > -                        const char *path)
> > -{
> > -     struct statx sx;
> > -
> > -     ASSERT_EQ(statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx), 0);
> > -     ASSERT_TRUE(!!(sx.stx_mask & STATX_MNT_ID_UNIQUE));
> > -     return sx.stx_mnt_id;
> > -}
> > -
> >   static const char root_mntpoint_templ[] = "/tmp/mount-notify_test_root.XXXXXX";
> >
> >   static const int mark_cmds[] = {
> > @@ -81,7 +72,7 @@ FIXTURE_SETUP(fanotify)
> >
> >       ASSERT_EQ(mkdir("b", 0700), 0);
> >
> > -     self->root_id = get_mnt_id(_metadata, "/");
> > +     self->root_id = get_unique_mnt_id("/");
> >       ASSERT_NE(self->root_id, 0);
> >
> >       for (i = 0; i < NUM_FAN_FDS; i++) {
> > diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile
> > index 19adebfc2620..8e354fe99b44 100644
> > --- a/tools/testing/selftests/filesystems/statmount/Makefile
> > +++ b/tools/testing/selftests/filesystems/statmount/Makefile
> > @@ -1,7 +1,10 @@
> >   # SPDX-License-Identifier: GPL-2.0-or-later
> >
> >   CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
> > +LDLIBS += -lcap
>
> And here.
>
> >
> >   TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
> >
> >   include ../../lib.mk
> > +
> > +$(OUTPUT)/statmount_test_ns: ../utils.c
>
> This is surprising: a new Makefile target, without removing an old one.
> And it's still listed in TEST_GEN_PROGS...
>
> Why did you feel the need to add this target?

I am not a makefile expert, but this states that statmount_test_ns
needs to link with utils.c code.

I copied it from overlayfs/Makefile.

Is there a different way to express this build dependency?

Thanks,
Amir.

Re: [PATCH 4/5] selftests/filesystems: create get_unique_mnt_id() helper

[John Hubbard]

On 5/8/25 4:44 AM, Amir Goldstein wrote:
> On Thu, May 8, 2025 at 9:43 AM John Hubbard <jhubbard@nvidia.com> wrote:
>> On 5/7/25 1:43 PM, Amir Goldstein wrote:
...
>>>   CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
>>> +LDLIBS += -lcap
>>
>> This addition of -lcap goes completely unmentioned in the commit log.
>> I'm guessing you are fixing things up to build, so this definitely
>> deserves an explanation there.
>>
> 
> This is needed because we are linking with utils.c code.
> See below.

I'll look into this.

> I guess we could have built a filesystems selftests utils library,
> but that seems like an operkill?

Definitely maximum overkill, and that's not where I was going, agreed. :)

Below...

...
>>> +$(OUTPUT)/statmount_test_ns: ../utils.c
>>
>> This is surprising: a new Makefile target, without removing an old one.
>> And it's still listed in TEST_GEN_PROGS...
>>
>> Why did you feel the need to add this target?
> 
> I am not a makefile expert, but this states that statmount_test_ns
> needs to link with utils.c code.
> 
> I copied it from overlayfs/Makefile.
> 
> Is there a different way to express this build dependency?
> 

Yes, but first I need to reload the kselftest build story back into
my head. I *almost* remember the answer offhand, but not quite! I'll
pull down your branch, just a sec.

thanks,
-- 
John Hubbard

Re: [PATCH 4/5] selftests/filesystems: create get_unique_mnt_id() helper

[John Hubbard]

On 5/8/25 12:35 PM, John Hubbard wrote:
> On 5/8/25 4:44 AM, Amir Goldstein wrote:
>> On Thu, May 8, 2025 at 9:43 AM John Hubbard <jhubbard@nvidia.com> wrote:
>>> On 5/7/25 1:43 PM, Amir Goldstein wrote:
> ...
>> Is there a different way to express this build dependency?
> 
> Yes, but first I need to reload the kselftest build story back into
> my head. I *almost* remember the answer offhand, but not quite! I'll
> pull down your branch, just a sec.
> 

OK, I finally got a moment to remember this, and your approach is
exactly correct after all! So please feel free to add:


Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard

[PATCH 5/5] selftests/filesystems: create setup_userns() helper

[Amir Goldstein]

Add helper to utils and use it in statmount userns tests.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 .../filesystems/statmount/statmount_test_ns.c | 60 +----------------
 tools/testing/selftests/filesystems/utils.c   | 65 +++++++++++++++++++
 tools/testing/selftests/filesystems/utils.h   |  1 +
 3 files changed, 68 insertions(+), 58 deletions(-)

diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
index 375a52101d08..3c5bc2e33821 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
+++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
@@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
 	return NSID_PASS;
 }
 
-static int write_file(const char *path, const char *val)
-{
-	int fd = open(path, O_WRONLY);
-	size_t len = strlen(val);
-	int ret;
-
-	if (fd == -1) {
-		ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
-		return NSID_ERROR;
-	}
-
-	ret = write(fd, val, len);
-	if (ret == -1) {
-		ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
-		return NSID_ERROR;
-	}
-	if (ret != len) {
-		ksft_print_msg("short write to %s\n", path);
-		return NSID_ERROR;
-	}
-
-	ret = close(fd);
-	if (ret == -1) {
-		ksft_print_msg("closing %s\n", path);
-		return NSID_ERROR;
-	}
-
-	return NSID_PASS;
-}
-
 static int setup_namespace(void)
 {
-	int ret;
-	char buf[32];
-	uid_t uid = getuid();
-	gid_t gid = getgid();
-
-	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
-	if (ret == -1)
-		ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
-				   strerror(errno));
-
-	sprintf(buf, "0 %d 1", uid);
-	ret = write_file("/proc/self/uid_map", buf);
-	if (ret != NSID_PASS)
-		return ret;
-	ret = write_file("/proc/self/setgroups", "deny");
-	if (ret != NSID_PASS)
-		return ret;
-	sprintf(buf, "0 %d 1", gid);
-	ret = write_file("/proc/self/gid_map", buf);
-	if (ret != NSID_PASS)
-		return ret;
-
-	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
-	if (ret == -1) {
-		ksft_print_msg("making mount tree private: %s\n",
-			       strerror(errno));
+	if (setup_userns() != 0)
 		return NSID_ERROR;
-	}
 
 	return NSID_PASS;
 }
@@ -200,7 +144,7 @@ static void test_statmount_mnt_ns_id(void)
 		return;
 	}
 
-	ret = setup_namespace();
+	ret = setup_userns();
 	if (ret != NSID_PASS)
 		exit(ret);
 	ret = _test_statmount_mnt_ns_id();
diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
index 9b5419e6f28d..9dab197ddd9c 100644
--- a/tools/testing/selftests/filesystems/utils.c
+++ b/tools/testing/selftests/filesystems/utils.c
@@ -18,6 +18,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/xattr.h>
+#include <sys/mount.h>
 
 #include "utils.h"
 
@@ -447,6 +448,70 @@ static int create_userns_hierarchy(struct userns_hierarchy *h)
 	return fret;
 }
 
+static int write_file(const char *path, const char *val)
+{
+	int fd = open(path, O_WRONLY);
+	size_t len = strlen(val);
+	int ret;
+
+	if (fd == -1) {
+		syserror("opening %s for write: %s\n", path, strerror(errno));
+		return -1;
+	}
+
+	ret = write(fd, val, len);
+	if (ret == -1) {
+		syserror("writing to %s: %s\n", path, strerror(errno));
+		return -1;
+	}
+	if (ret != len) {
+		syserror("short write to %s\n", path);
+		return -1;
+	}
+
+	ret = close(fd);
+	if (ret == -1) {
+		syserror("closing %s\n", path);
+		return -1;
+	}
+
+	return 0;
+}
+
+int setup_userns(void)
+{
+	int ret;
+	char buf[32];
+	uid_t uid = getuid();
+	gid_t gid = getgid();
+
+	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
+	if (ret) {
+		syserror("unsharing mountns and userns: %s\n", strerror(errno));
+		return ret;
+	}
+
+	sprintf(buf, "0 %d 1", uid);
+	ret = write_file("/proc/self/uid_map", buf);
+	if (ret)
+		return ret;
+	ret = write_file("/proc/self/setgroups", "deny");
+	if (ret)
+		return ret;
+	sprintf(buf, "0 %d 1", gid);
+	ret = write_file("/proc/self/gid_map", buf);
+	if (ret)
+		return ret;
+
+	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
+	if (ret) {
+		syserror("making mount tree private: %s\n", strerror(errno));
+		return ret;
+	}
+
+	return 0;
+}
+
 /* caps_down - lower all effective caps */
 int caps_down(void)
 {
diff --git a/tools/testing/selftests/filesystems/utils.h b/tools/testing/selftests/filesystems/utils.h
index d9cf145b321a..70f7ccc607f4 100644
--- a/tools/testing/selftests/filesystems/utils.h
+++ b/tools/testing/selftests/filesystems/utils.h
@@ -27,6 +27,7 @@ extern int caps_down(void);
 extern int cap_down(cap_value_t down);
 
 extern bool switch_ids(uid_t uid, gid_t gid);
+extern int setup_userns(void);
 
 static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)
 {
-- 
2.34.1

Re: [PATCH 5/5] selftests/filesystems: create setup_userns() helper

[John Hubbard]

On 5/7/25 1:43 PM, Amir Goldstein wrote:
> Add helper to utils and use it in statmount userns tests.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>   .../filesystems/statmount/statmount_test_ns.c | 60 +----------------
>   tools/testing/selftests/filesystems/utils.c   | 65 +++++++++++++++++++
>   tools/testing/selftests/filesystems/utils.h   |  1 +
>   3 files changed, 68 insertions(+), 58 deletions(-)
> 
> diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> index 375a52101d08..3c5bc2e33821 100644
> --- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> +++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> @@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
>   	return NSID_PASS;
>   }
>   
> -static int write_file(const char *path, const char *val)
> -{
> -	int fd = open(path, O_WRONLY);
> -	size_t len = strlen(val);
> -	int ret;
> -
> -	if (fd == -1) {
> -		ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
> -		return NSID_ERROR;
> -	}
> -
> -	ret = write(fd, val, len);
> -	if (ret == -1) {
> -		ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
> -		return NSID_ERROR;
> -	}
> -	if (ret != len) {
> -		ksft_print_msg("short write to %s\n", path);
> -		return NSID_ERROR;
> -	}
> -
> -	ret = close(fd);
> -	if (ret == -1) {
> -		ksft_print_msg("closing %s\n", path);
> -		return NSID_ERROR;
> -	}
> -
> -	return NSID_PASS;
> -}
> -
>   static int setup_namespace(void)
>   {
> -	int ret;
> -	char buf[32];
> -	uid_t uid = getuid();
> -	gid_t gid = getgid();
> -
> -	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
> -	if (ret == -1)
> -		ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
> -				   strerror(errno));
> -
> -	sprintf(buf, "0 %d 1", uid);
> -	ret = write_file("/proc/self/uid_map", buf);
> -	if (ret != NSID_PASS)
> -		return ret;
> -	ret = write_file("/proc/self/setgroups", "deny");
> -	if (ret != NSID_PASS)
> -		return ret;
> -	sprintf(buf, "0 %d 1", gid);
> -	ret = write_file("/proc/self/gid_map", buf);
> -	if (ret != NSID_PASS)
> -		return ret;
> -
> -	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
> -	if (ret == -1) {
> -		ksft_print_msg("making mount tree private: %s\n",
> -			       strerror(errno));
> +	if (setup_userns() != 0)
>   		return NSID_ERROR;
> -	}
>   
>   	return NSID_PASS;
>   }
> @@ -200,7 +144,7 @@ static void test_statmount_mnt_ns_id(void)
>   		return;
>   	}
>   
> -	ret = setup_namespace();
> +	ret = setup_userns();
>   	if (ret != NSID_PASS)
>   		exit(ret);
>   	ret = _test_statmount_mnt_ns_id();
> diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
> index 9b5419e6f28d..9dab197ddd9c 100644
> --- a/tools/testing/selftests/filesystems/utils.c
> +++ b/tools/testing/selftests/filesystems/utils.c
> @@ -18,6 +18,7 @@
>   #include <sys/types.h>
>   #include <sys/wait.h>
>   #include <sys/xattr.h>
> +#include <sys/mount.h>
>   
>   #include "utils.h"
>   
> @@ -447,6 +448,70 @@ static int create_userns_hierarchy(struct userns_hierarchy *h)
>   	return fret;
>   }
>   
> +static int write_file(const char *path, const char *val)
> +{
> +	int fd = open(path, O_WRONLY);
> +	size_t len = strlen(val);
> +	int ret;
> +
> +	if (fd == -1) {
> +		syserror("opening %s for write: %s\n", path, strerror(errno));

While I have no opinion about ksft_print_msg() vs. syserror(), I do
think it's worth a mention in the commit log: there is some reason
that you changed to syserror() throughout. Could you write down
what that was?

In any case, it looks correct, so with an update commit message, please
feel free to add:


Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard


> +		return -1;
> +	}
> +
> +	ret = write(fd, val, len);
> +	if (ret == -1) {
> +		syserror("writing to %s: %s\n", path, strerror(errno));
> +		return -1;
> +	}
> +	if (ret != len) {
> +		syserror("short write to %s\n", path);
> +		return -1;
> +	}
> +
> +	ret = close(fd);
> +	if (ret == -1) {
> +		syserror("closing %s\n", path);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +int setup_userns(void)
> +{
> +	int ret;
> +	char buf[32];
> +	uid_t uid = getuid();
> +	gid_t gid = getgid();
> +
> +	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
> +	if (ret) {
> +		syserror("unsharing mountns and userns: %s\n", strerror(errno));
> +		return ret;
> +	}
> +
> +	sprintf(buf, "0 %d 1", uid);
> +	ret = write_file("/proc/self/uid_map", buf);
> +	if (ret)
> +		return ret;
> +	ret = write_file("/proc/self/setgroups", "deny");
> +	if (ret)
> +		return ret;
> +	sprintf(buf, "0 %d 1", gid);
> +	ret = write_file("/proc/self/gid_map", buf);
> +	if (ret)
> +		return ret;
> +
> +	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
> +	if (ret) {
> +		syserror("making mount tree private: %s\n", strerror(errno));
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>   /* caps_down - lower all effective caps */
>   int caps_down(void)
>   {
> diff --git a/tools/testing/selftests/filesystems/utils.h b/tools/testing/selftests/filesystems/utils.h
> index d9cf145b321a..70f7ccc607f4 100644
> --- a/tools/testing/selftests/filesystems/utils.h
> +++ b/tools/testing/selftests/filesystems/utils.h
> @@ -27,6 +27,7 @@ extern int caps_down(void);
>   extern int cap_down(cap_value_t down);
>   
>   extern bool switch_ids(uid_t uid, gid_t gid);
> +extern int setup_userns(void);
>   
>   static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)
>   {

Re: [PATCH 5/5] selftests/filesystems: create setup_userns() helper

[Amir Goldstein]

On Thu, May 8, 2025 at 9:52 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 5/7/25 1:43 PM, Amir Goldstein wrote:
> > Add helper to utils and use it in statmount userns tests.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> >   .../filesystems/statmount/statmount_test_ns.c | 60 +----------------
> >   tools/testing/selftests/filesystems/utils.c   | 65 +++++++++++++++++++
> >   tools/testing/selftests/filesystems/utils.h   |  1 +
> >   3 files changed, 68 insertions(+), 58 deletions(-)
> >
> > diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > index 375a52101d08..3c5bc2e33821 100644
> > --- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > +++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > @@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
> >       return NSID_PASS;
> >   }
> >
> > -static int write_file(const char *path, const char *val)
> > -{
> > -     int fd = open(path, O_WRONLY);
> > -     size_t len = strlen(val);
> > -     int ret;
> > -
> > -     if (fd == -1) {
> > -             ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
> > -             return NSID_ERROR;
> > -     }
> > -
> > -     ret = write(fd, val, len);
> > -     if (ret == -1) {
> > -             ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
> > -             return NSID_ERROR;
> > -     }
> > -     if (ret != len) {
> > -             ksft_print_msg("short write to %s\n", path);
> > -             return NSID_ERROR;
> > -     }
> > -
> > -     ret = close(fd);
> > -     if (ret == -1) {
> > -             ksft_print_msg("closing %s\n", path);
> > -             return NSID_ERROR;
> > -     }
> > -
> > -     return NSID_PASS;
> > -}
> > -
> >   static int setup_namespace(void)
> >   {
> > -     int ret;
> > -     char buf[32];
> > -     uid_t uid = getuid();
> > -     gid_t gid = getgid();
> > -
> > -     ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
> > -     if (ret == -1)
> > -             ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
> > -                                strerror(errno));
> > -
> > -     sprintf(buf, "0 %d 1", uid);
> > -     ret = write_file("/proc/self/uid_map", buf);
> > -     if (ret != NSID_PASS)
> > -             return ret;
> > -     ret = write_file("/proc/self/setgroups", "deny");
> > -     if (ret != NSID_PASS)
> > -             return ret;
> > -     sprintf(buf, "0 %d 1", gid);
> > -     ret = write_file("/proc/self/gid_map", buf);
> > -     if (ret != NSID_PASS)
> > -             return ret;
> > -
> > -     ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
> > -     if (ret == -1) {
> > -             ksft_print_msg("making mount tree private: %s\n",
> > -                            strerror(errno));
> > +     if (setup_userns() != 0)
> >               return NSID_ERROR;
> > -     }
> >
> >       return NSID_PASS;
> >   }
> > @@ -200,7 +144,7 @@ static void test_statmount_mnt_ns_id(void)
> >               return;
> >       }
> >
> > -     ret = setup_namespace();
> > +     ret = setup_userns();
> >       if (ret != NSID_PASS)
> >               exit(ret);
> >       ret = _test_statmount_mnt_ns_id();
> > diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
> > index 9b5419e6f28d..9dab197ddd9c 100644
> > --- a/tools/testing/selftests/filesystems/utils.c
> > +++ b/tools/testing/selftests/filesystems/utils.c
> > @@ -18,6 +18,7 @@
> >   #include <sys/types.h>
> >   #include <sys/wait.h>
> >   #include <sys/xattr.h>
> > +#include <sys/mount.h>
> >
> >   #include "utils.h"
> >
> > @@ -447,6 +448,70 @@ static int create_userns_hierarchy(struct userns_hierarchy *h)
> >       return fret;
> >   }
> >
> > +static int write_file(const char *path, const char *val)
> > +{
> > +     int fd = open(path, O_WRONLY);
> > +     size_t len = strlen(val);
> > +     int ret;
> > +
> > +     if (fd == -1) {
> > +             syserror("opening %s for write: %s\n", path, strerror(errno));
>
> While I have no opinion about ksft_print_msg() vs. syserror(), I do
> think it's worth a mention in the commit log: there is some reason
> that you changed to syserror() throughout. Could you write down
> what that was?

Very good question.

I admit I did not put much thought into this. I was blindly following
Christian's lead in utils.c.
I will revert those syserror back to ksft_print_msg().

>
> In any case, it looks correct, so with an update commit message, please
> feel free to add:
>
>
> Reviewed-by: John Hubbard <jhubbard@nvidia.com>
>

Thanks for the review!
Amir.

Re: [PATCH 5/5] selftests/filesystems: create setup_userns() helper

[Christian Brauner]

On Thu, May 08, 2025 at 02:08:16PM +0200, Amir Goldstein wrote:
> On Thu, May 8, 2025 at 9:52 AM John Hubbard <jhubbard@nvidia.com> wrote:
> >
> > On 5/7/25 1:43 PM, Amir Goldstein wrote:
> > > Add helper to utils and use it in statmount userns tests.
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> > >   .../filesystems/statmount/statmount_test_ns.c | 60 +----------------
> > >   tools/testing/selftests/filesystems/utils.c   | 65 +++++++++++++++++++
> > >   tools/testing/selftests/filesystems/utils.h   |  1 +
> > >   3 files changed, 68 insertions(+), 58 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > > index 375a52101d08..3c5bc2e33821 100644
> > > --- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > > +++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> > > @@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
> > >       return NSID_PASS;
> > >   }
> > >
> > > -static int write_file(const char *path, const char *val)
> > > -{
> > > -     int fd = open(path, O_WRONLY);
> > > -     size_t len = strlen(val);
> > > -     int ret;
> > > -
> > > -     if (fd == -1) {
> > > -             ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
> > > -             return NSID_ERROR;
> > > -     }
> > > -
> > > -     ret = write(fd, val, len);
> > > -     if (ret == -1) {
> > > -             ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
> > > -             return NSID_ERROR;
> > > -     }
> > > -     if (ret != len) {
> > > -             ksft_print_msg("short write to %s\n", path);
> > > -             return NSID_ERROR;
> > > -     }
> > > -
> > > -     ret = close(fd);
> > > -     if (ret == -1) {
> > > -             ksft_print_msg("closing %s\n", path);
> > > -             return NSID_ERROR;
> > > -     }
> > > -
> > > -     return NSID_PASS;
> > > -}
> > > -
> > >   static int setup_namespace(void)
> > >   {
> > > -     int ret;
> > > -     char buf[32];
> > > -     uid_t uid = getuid();
> > > -     gid_t gid = getgid();
> > > -
> > > -     ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
> > > -     if (ret == -1)
> > > -             ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
> > > -                                strerror(errno));
> > > -
> > > -     sprintf(buf, "0 %d 1", uid);
> > > -     ret = write_file("/proc/self/uid_map", buf);
> > > -     if (ret != NSID_PASS)
> > > -             return ret;
> > > -     ret = write_file("/proc/self/setgroups", "deny");
> > > -     if (ret != NSID_PASS)
> > > -             return ret;
> > > -     sprintf(buf, "0 %d 1", gid);
> > > -     ret = write_file("/proc/self/gid_map", buf);
> > > -     if (ret != NSID_PASS)
> > > -             return ret;
> > > -
> > > -     ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
> > > -     if (ret == -1) {
> > > -             ksft_print_msg("making mount tree private: %s\n",
> > > -                            strerror(errno));
> > > +     if (setup_userns() != 0)
> > >               return NSID_ERROR;
> > > -     }
> > >
> > >       return NSID_PASS;
> > >   }
> > > @@ -200,7 +144,7 @@ static void test_statmount_mnt_ns_id(void)
> > >               return;
> > >       }
> > >
> > > -     ret = setup_namespace();
> > > +     ret = setup_userns();
> > >       if (ret != NSID_PASS)
> > >               exit(ret);
> > >       ret = _test_statmount_mnt_ns_id();
> > > diff --git a/tools/testing/selftests/filesystems/utils.c b/tools/testing/selftests/filesystems/utils.c
> > > index 9b5419e6f28d..9dab197ddd9c 100644
> > > --- a/tools/testing/selftests/filesystems/utils.c
> > > +++ b/tools/testing/selftests/filesystems/utils.c
> > > @@ -18,6 +18,7 @@
> > >   #include <sys/types.h>
> > >   #include <sys/wait.h>
> > >   #include <sys/xattr.h>
> > > +#include <sys/mount.h>
> > >
> > >   #include "utils.h"
> > >
> > > @@ -447,6 +448,70 @@ static int create_userns_hierarchy(struct userns_hierarchy *h)
> > >       return fret;
> > >   }
> > >
> > > +static int write_file(const char *path, const char *val)
> > > +{
> > > +     int fd = open(path, O_WRONLY);
> > > +     size_t len = strlen(val);
> > > +     int ret;
> > > +
> > > +     if (fd == -1) {
> > > +             syserror("opening %s for write: %s\n", path, strerror(errno));
> >
> > While I have no opinion about ksft_print_msg() vs. syserror(), I do
> > think it's worth a mention in the commit log: there is some reason
> > that you changed to syserror() throughout. Could you write down
> > what that was?
> 
> Very good question.
> 
> I admit I did not put much thought into this. I was blindly following
> Christian's lead in utils.c.
> I will revert those syserror back to ksft_print_msg().

I think I copied parts of that over from the work I did for xfstests
testing.

Re: [PATCH 5/5] selftests/filesystems: create setup_userns() helper

[Amir Goldstein]

On Wed, May 7, 2025 at 10:43 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> Add helper to utils and use it in statmount userns tests.
>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>  .../filesystems/statmount/statmount_test_ns.c | 60 +----------------
>  tools/testing/selftests/filesystems/utils.c   | 65 +++++++++++++++++++
>  tools/testing/selftests/filesystems/utils.h   |  1 +
>  3 files changed, 68 insertions(+), 58 deletions(-)
>
> diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> index 375a52101d08..3c5bc2e33821 100644
> --- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> +++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
> @@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
>         return NSID_PASS;
>  }
>
> -static int write_file(const char *path, const char *val)
> -{
> -       int fd = open(path, O_WRONLY);
> -       size_t len = strlen(val);
> -       int ret;
> -
> -       if (fd == -1) {
> -               ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
> -               return NSID_ERROR;
> -       }
> -
> -       ret = write(fd, val, len);
> -       if (ret == -1) {
> -               ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
> -               return NSID_ERROR;
> -       }
> -       if (ret != len) {
> -               ksft_print_msg("short write to %s\n", path);
> -               return NSID_ERROR;
> -       }
> -
> -       ret = close(fd);
> -       if (ret == -1) {
> -               ksft_print_msg("closing %s\n", path);
> -               return NSID_ERROR;
> -       }
> -
> -       return NSID_PASS;
> -}
> -
>  static int setup_namespace(void)
>  {
> -       int ret;
> -       char buf[32];
> -       uid_t uid = getuid();
> -       gid_t gid = getgid();
> -
> -       ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
> -       if (ret == -1)
> -               ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
> -                                  strerror(errno));
> -
> -       sprintf(buf, "0 %d 1", uid);
> -       ret = write_file("/proc/self/uid_map", buf);
> -       if (ret != NSID_PASS)
> -               return ret;
> -       ret = write_file("/proc/self/setgroups", "deny");
> -       if (ret != NSID_PASS)
> -               return ret;
> -       sprintf(buf, "0 %d 1", gid);
> -       ret = write_file("/proc/self/gid_map", buf);
> -       if (ret != NSID_PASS)
> -               return ret;
> -
> -       ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
> -       if (ret == -1) {
> -               ksft_print_msg("making mount tree private: %s\n",
> -                              strerror(errno));
> +       if (setup_userns() != 0)
>                 return NSID_ERROR;
> -       }
>
>         return NSID_PASS;
>  }
> @@ -200,7 +144,7 @@ static void test_statmount_mnt_ns_id(void)
>                 return;
>         }
>
> -       ret = setup_namespace();
> +       ret = setup_userns();

FYI, this is a braino.
It should remain setup_namespace()

Pushed a branch to my github will all review fixes and a WIP
mount-notify-ns_test:

https://github.com/amir73il/linux/commits/fanotify_selftests/

Thanks,
Amir.

Re: [PATCH 5/5] selftests/filesystems: create setup_userns() helper

[John Hubbard]

On 5/8/25 5:40 AM, Amir Goldstein wrote:
> On Wed, May 7, 2025 at 10:43 PM Amir Goldstein <amir73il@gmail.com> wrote:
.... 
> Pushed a branch to my github will all review fixes and a WIP
> mount-notify-ns_test:
> 
> https://github.com/amir73il/linux/commits/fanotify_selftests/
> 

It's always nice when people provide a pre-cooked branch to pull
down, as it removes the grand glorious guessing game of whether the
patches will apply to $tree. :)

I've pulled this down and will take a quick peek at the Makefile
question in the other thread.

thanks,
-- 
John Hubbard