The extents KUnit test uses sget() to get an initialized superblock for
its fake file_system_type. sget() predates fs_context and we want to
retire it. Switch this caller over to sget_fc().

Add a no-op ext_init_fs_context() so fs_context_for_mount() has
something to call on the fake fs_type. ext_set() now takes a struct
fs_context * (still a no-op). extents_kunit_init() allocates the fc,
hands it to sget_fc() and drops the fc reference once the sb is
published. sget_fc() does not retain a pointer to it.

No functional change for the test.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/ext4/extents-test.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/extents-test.c b/fs/ext4/extents-test.c
index 6b53a3f39fcd..bd7795a82607 100644
--- a/fs/ext4/extents-test.c
+++ b/fs/ext4/extents-test.c
@@ -37,6 +37,7 @@
 
 #include <kunit/test.h>
 #include <kunit/static_stub.h>
+#include <linux/fs_context.h>
 #include <linux/gfp_types.h>
 #include <linux/stddef.h>
 
@@ -130,14 +131,20 @@ static void ext_kill_sb(struct super_block *sb)
 	generic_shutdown_super(sb);
 }
 
-static int ext_set(struct super_block *sb, void *data)
+static int ext_init_fs_context(struct fs_context *fc)
+{
+	return 0;
+}
+
+static int ext_set(struct super_block *sb, struct fs_context *fc)
 {
 	return 0;
 }
 
 static struct file_system_type ext_fs_type = {
-	.name = "extents test",
-	.kill_sb = ext_kill_sb,
+	.name		 = "extents test",
+	.init_fs_context = ext_init_fs_context,
+	.kill_sb	 = ext_kill_sb,
 };
 
 static void extents_kunit_exit(struct kunit *test)
@@ -223,6 +230,7 @@ static int extents_kunit_init(struct kunit *test)
 	struct ext4_inode_info *ei;
 	struct inode *inode;
 	struct super_block *sb;
+	struct fs_context *fc;
 	struct ext4_sb_info *sbi = NULL;
 	struct kunit_ext_test_param *param =
 		(struct kunit_ext_test_param *)(test->param_value);
@@ -232,7 +240,13 @@ static int extents_kunit_init(struct kunit *test)
 	if (sbi == NULL)
 		return -ENOMEM;
 
-	sb = sget(&ext_fs_type, NULL, ext_set, 0, NULL);
+	fc = fs_context_for_mount(&ext_fs_type, 0);
+	if (IS_ERR(fc)) {
+		kfree(sbi);
+		return PTR_ERR(fc);
+	}
+	sb = sget_fc(fc, NULL, ext_set);
+	put_fs_context(fc);
 	if (IS_ERR(sb)) {
 		kfree(sbi);
 		return PTR_ERR(sb);

-- 
2.47.3