[LTP] [PATCH 2/3] fanotify13: Test watching overlayfs with FAN_REPORT_FID

[Amir Goldstein]

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

This requires overlayfs support for AT_HANDLE_FID.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 testcases/kernel/syscalls/fanotify/fanotify.h   | 15 +++++++++++----
 testcases/kernel/syscalls/fanotify/fanotify13.c |  7 +++++--
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/testcases/kernel/syscalls/fanotify/fanotify.h b/testcases/kernel/syscalls/fanotify/fanotify.h
index 75a081dc9..eea1dad91 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify.h
+++ b/testcases/kernel/syscalls/fanotify/fanotify.h
@@ -93,6 +93,11 @@ 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;
+
 			tst_brk(TCONF,
 				"filesystem %s does not support file handles",
 				tst_device->fs_type);
@@ -179,6 +184,7 @@ 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 +205,7 @@ 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",
@@ -226,10 +232,11 @@ 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 adba41453..5c1d287d7 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify13.c
+++ b/testcases/kernel/syscalls/fanotify/fanotify13.c
@@ -287,6 +287,7 @@ static void do_setup(void)
 	 * Bind mount to either base fs or to overlayfs over base fs:
 	 * Variant #0: watch base fs - open files on base fs
 	 * Variant #1: watch upper fs - open files on overlayfs
+	 * Variant #2: watch overlayfs - open files on overlayfs
 	 *
 	 * Variant #1 tests a bug whose fix bc2473c90fca ("ovl: enable fsnotify
 	 * events on underlying real files") in kernel 6.5 is not likely to be
@@ -294,11 +295,13 @@ 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.
+	 * Variant #2 tests 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);
 		ovl_mounted = TST_MOUNT_OVERLAY();
-		mnt = OVL_UPPER;
+		mnt = tst_variant == 1 ? OVL_UPPER : OVL_MNT;
 	} else {
 		mnt = OVL_BASE_MNTPOINT;
 
@@ -343,7 +346,7 @@ static void do_cleanup(void)
 static struct tst_test test = {
 	.test = do_test,
 	.tcnt = ARRAY_SIZE(test_cases),
-	.test_variants = 2,
+	.test_variants = 3,
 	.setup = do_setup,
 	.cleanup = do_cleanup,
 	.needs_root = 1,
-- 
2.34.1