[LTP] [PATCH 2/2] fanotify13: Test watching overlayfs with FAN_REPORT_FID

Amir Goldstein amir73il@gmail.com
Tue Nov 14 08:23:38 CET 2023


Run test variants watching overlayfs (over all supported fs)
and reporting events with fid.

This requires overlayfs support for AT_HANDLE_FID (kernel 6.6) and
even with AT_HANDLE_FID file handles, only inode marks are supported.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 testcases/kernel/syscalls/fanotify/fanotify.h | 28 ++++++++++++-----
 .../kernel/syscalls/fanotify/fanotify13.c     | 31 ++++++++++++++++---
 2 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/testcases/kernel/syscalls/fanotify/fanotify.h b/testcases/kernel/syscalls/fanotify/fanotify.h
index 78424a350..a8aec6597 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify.h
+++ b/testcases/kernel/syscalls/fanotify/fanotify.h
@@ -79,8 +79,11 @@ static inline int safe_fanotify_mark(const char *file, const int lineno,
 /*
  * Helper function used to obtain fsid and file_handle for a given path.
  * Used by test files correlated to FAN_REPORT_FID functionality.
+ *
+ * Returns 0 if normal NFS file handles are supported.
+ * Returns AT_HANDLE_FID, of only non-decodeable file handles are supported.
  */
-static inline void fanotify_get_fid(const char *path, __kernel_fsid_t *fsid,
+static inline int fanotify_get_fid(const char *path, __kernel_fsid_t *fsid,
 				    struct file_handle *handle)
 {
 	int mount_id;
@@ -93,6 +96,11 @@ static inline void fanotify_get_fid(const char *path, __kernel_fsid_t *fsid,
 
 	if (name_to_handle_at(AT_FDCWD, path, handle, &mount_id, 0) == -1) {
 		if (errno == EOPNOTSUPP) {
+			/* Try to request non-decodeable fid instead */
+			if (name_to_handle_at(AT_FDCWD, path, handle, &mount_id,
+					      AT_HANDLE_FID) == 0)
+				return AT_HANDLE_FID;
+
 			tst_brk(TCONF,
 				"filesystem %s does not support file handles",
 				tst_device->fs_type);
@@ -100,6 +108,7 @@ static inline void fanotify_get_fid(const char *path, __kernel_fsid_t *fsid,
 		tst_brk(TBROK | TERRNO,
 			"name_to_handle_at(AT_FDCWD, %s, ...) failed", path);
 	}
+	return 0;
 }
 
 #ifndef FILEID_INVALID
@@ -112,18 +121,21 @@ struct fanotify_fid_t {
 	char buf[MAX_HANDLE_SZ];
 };
 
-static inline void fanotify_save_fid(const char *path,
+static inline int fanotify_save_fid(const char *path,
 				     struct fanotify_fid_t *fid)
 {
 	int *fh = (int *)(fid->handle.f_handle);
+	int ret;
 
 	fh[0] = fh[1] = fh[2] = 0;
 	fid->handle.handle_bytes = MAX_HANDLE_SZ;
-	fanotify_get_fid(path, &fid->fsid, &fid->handle);
+	ret = fanotify_get_fid(path, &fid->fsid, &fid->handle);
 
 	tst_res(TINFO,
 		"fid(%s) = %x.%x.%x.%x.%x...", path, fid->fsid.val[0],
 		fid->fsid.val[1], fh[0], fh[1], fh[2]);
+
+	return ret;
 }
 #endif /* HAVE_NAME_TO_HANDLE_AT */
 
@@ -179,6 +191,7 @@ static inline int fanotify_events_supported_by_kernel(uint64_t mask,
  * @return  0: fanotify supported both in kernel and on tested filesystem
  * @return -1: @flags not supported in kernel
  * @return -2: @flags not supported on tested filesystem (tested if @fname is not NULL)
+ * @return -3: @flags not supported on overlayfs (tested if @fname == OVL_MNT)
  */
 static inline int fanotify_init_flags_supported_on_fs(unsigned int flags, const char *fname)
 {
@@ -199,7 +212,7 @@ static inline int fanotify_init_flags_supported_on_fs(unsigned int flags, const
 
 	if (fname && fanotify_mark(fd, FAN_MARK_ADD, FAN_ACCESS, AT_FDCWD, fname) < 0) {
 		if (errno == ENODEV || errno == EOPNOTSUPP || errno == EXDEV) {
-			rval = -2;
+			rval = strcmp(fname, OVL_MNT) ? -2 : -3;
 		} else {
 			tst_brk(TBROK | TERRNO,
 				"fanotify_mark (%d, FAN_MARK_ADD, ..., AT_FDCWD, %s) failed",
@@ -269,10 +282,11 @@ static inline void fanotify_init_flags_err_msg(const char *flags_str,
 	if (fail == -1)
 		res_func(file, lineno, TCONF,
 			 "%s not supported in kernel?", flags_str);
-	if (fail == -2)
+	if (fail == -2 || fail == -3)
 		res_func(file, lineno, TCONF,
-			 "%s not supported on %s filesystem",
-			 flags_str, tst_device->fs_type);
+			 "%s not supported on %s%s filesystem",
+			 flags_str, fail == -3 ? "overlayfs over " : "",
+			 tst_device->fs_type);
 }
 
 #define FANOTIFY_INIT_FLAGS_ERR_MSG(flags, fail) \
diff --git a/testcases/kernel/syscalls/fanotify/fanotify13.c b/testcases/kernel/syscalls/fanotify/fanotify13.c
index 4bcffaab2..4a7c2af23 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify13.c
+++ b/testcases/kernel/syscalls/fanotify/fanotify13.c
@@ -91,8 +91,10 @@ static struct test_case_t {
 
 static int ovl_mounted;
 static int bind_mounted;
+static int ovl_bind_mounted;
 static int nofid_fd;
 static int fanotify_fd;
+static int at_handle_fid;
 static int filesystem_mark_unsupported;
 static char events_buf[BUF_SIZE];
 static struct event_t event_set[EVENT_MAX];
@@ -113,8 +115,10 @@ static void get_object_stats(void)
 {
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(objects); i++)
-		fanotify_save_fid(objects[i].path, &objects[i].fid);
+	for (i = 0; i < ARRAY_SIZE(objects); i++) {
+		at_handle_fid |=
+			fanotify_save_fid(objects[i].path, &objects[i].fid);
+	}
 }
 
 static int setup_marks(unsigned int fd, struct test_case_t *tc)
@@ -154,6 +158,11 @@ static void do_test(unsigned int number)
 		return;
 	}
 
+	if (at_handle_fid && mark->flag != FAN_MARK_INODE) {
+		tst_res(TCONF, "overlayfs does not support decodeable file handles required by %s", mark->name);
+		return;
+	}
+
 	if (filesystem_mark_unsupported && mark->flag & FAN_MARK_FILESYSTEM) {
 		tst_res(TCONF, "FAN_MARK_FILESYSTEM not supported in kernel?");
 		return;
@@ -169,7 +178,7 @@ static void do_test(unsigned int number)
 		goto out;
 
 	/* Watching base fs - open files on overlayfs */
-	if (tst_variant) {
+	if (tst_variant && !ovl_bind_mounted) {
 		if (mark->flag & FAN_MARK_MOUNT) {
 			tst_res(TCONF, "overlayfs base fs cannot be watched with mount mark");
 			goto out;
@@ -191,7 +200,7 @@ static void do_test(unsigned int number)
 			SAFE_CLOSE(fds[i]);
 	}
 
-	if (tst_variant)
+	if (tst_variant && !ovl_bind_mounted)
 		SAFE_UMOUNT(MOUNT_PATH);
 
 	/* Read events from event queue */
@@ -288,6 +297,8 @@ static void do_setup(void)
 	 * Variant #0: watch base fs - open files on base fs
 	 * Variant #1: watch lower fs - open lower files on overlayfs
 	 * Variant #2: watch upper fs - open upper files on overlayfs
+	 * Variant #3: watch overlayfs - open lower files on overlayfs
+	 * Variant #4: watch overlayfs - open upper files on overlayfs
 	 *
 	 * Variants 1,2 test a bug whose fix bc2473c90fca ("ovl: enable fsnotify
 	 * events on underlying real files") in kernel 6.5 is not likely to be
@@ -295,6 +306,8 @@ static void do_setup(void)
 	 * To avoid waiting for events that won't arrive when testing old kernels,
 	 * require that kernel supports encoding fid with new flag AT_HADNLE_FID,
 	 * also merged to 6.5 and not likely to be backported to older kernels.
+	 * Variants 3,4 test overlayfs watch with FAN_REPORT_FID, which also
+	 * requires kernel with support for AT_HADNLE_FID.
 	 */
 	if (tst_variant) {
 		REQUIRE_HANDLE_TYPE_SUPPORTED_BY_KERNEL(AT_HANDLE_FID);
@@ -319,6 +332,12 @@ static void do_setup(void)
 	/* Create file and directory objects for testing on base fs */
 	create_objects();
 
+	if (tst_variant > 2) {
+		/* Setup watches on overlayfs */
+		SAFE_MOUNT(OVL_MNT, MOUNT_PATH, "none", MS_BIND, NULL);
+		ovl_bind_mounted = 1;
+	}
+
 	/*
 	 * Create a mark on first inode without FAN_REPORT_FID, to test
 	 * uninitialized connector->fsid cache. This mark remains for all test
@@ -337,6 +356,8 @@ static void do_cleanup(void)
 		SAFE_CLOSE(nofid_fd);
 	if (fanotify_fd > 0)
 		SAFE_CLOSE(fanotify_fd);
+	if (ovl_bind_mounted)
+		SAFE_UMOUNT(MOUNT_PATH);
 	if (bind_mounted) {
 		SAFE_UMOUNT(MOUNT_PATH);
 		SAFE_RMDIR(MOUNT_PATH);
@@ -348,7 +369,7 @@ static void do_cleanup(void)
 static struct tst_test test = {
 	.test = do_test,
 	.tcnt = ARRAY_SIZE(test_cases),
-	.test_variants = 3,
+	.test_variants = 5,
 	.setup = do_setup,
 	.cleanup = do_cleanup,
 	.needs_root = 1,
-- 
2.34.1



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