From 669de459a7685b59b5c65d29e13ca9c7c2a9a481 Mon Sep 17 00:00:00 2001
From: Auke Kok <auke.kok@versity.com>
Date: Fri, 8 Nov 2024 18:55:14 -0500
Subject: [PATCH] bdev_open_by_path is now removed as well.

Additional blkdev/bdev changes now cause this call to be removed as
well resulting in us having to use yet another API to do the same for
el9_5.

The changes are a little more subtle as now the bdev_mount() call passes
a custom bd_holder_ops that we must match or else throw a WARN_ON, so we
switch to using sbi as our holder arg instead.

Make sure to bdev_fput and not fput, since we don't want to have our
private data cleanup deferred, failing xfstests generic/604.

Signed-off-by: Auke Kok <auke.kok@versity.com>
---
 kmod/src/Makefile.kernelcompat |  9 +++++++++
 kmod/src/super.c               | 28 ++++++++++++++++++++++++++++
 kmod/src/super.h               |  3 +++
 3 files changed, 40 insertions(+)

diff --git a/kmod/src/Makefile.kernelcompat b/kmod/src/Makefile.kernelcompat
index 5f21c6be..403a2f66 100644
--- a/kmod/src/Makefile.kernelcompat
+++ b/kmod/src/Makefile.kernelcompat
@@ -422,3 +422,12 @@ endif
 ifneq (,$(shell grep 'struct backing_dev_info.*backing_dev_info;' include/linux/sched.h))
 ccflags-y += -DKC_CURRENT_BACKING_DEV_INFO
 endif
+
+#
+# v6.8-rc1-4-gf3a608827d1f
+#
+# adds bdev_file_open_by_path() and later in v6.8-rc1-30-ge97d06a46526 removes bdev_open_by_path()
+# which requires us to use the file method from now on.
+ifneq (,$(shell grep 'struct file.*bdev_file_open_by_path.const char.*path' include/linux/blkdev.h))
+ccflags-y += -DKC_BDEV_FILE_OPEN_BY_PATH
+endif
diff --git a/kmod/src/super.c b/kmod/src/super.c
index b9428ca3..16ab2343 100644
--- a/kmod/src/super.c
+++ b/kmod/src/super.c
@@ -160,11 +160,17 @@ static void scoutfs_metadev_close(struct super_block *sb)
 		 * from kill_sb->put_super.
 		 */
 		lockdep_off();
+
+#ifdef KC_BDEV_FILE_OPEN_BY_PATH
+		bdev_fput(sbi->meta_bdev_file);
+#else
 #ifdef KC_BLKDEV_PUT_HOLDER_ARG
 		blkdev_put(sbi->meta_bdev, sb);
 #else
 		blkdev_put(sbi->meta_bdev, SCOUTFS_META_BDEV_MODE);
 #endif
+#endif
+
 		lockdep_on();
 		sbi->meta_bdev = NULL;
 	}
@@ -481,7 +487,11 @@ out:
 static int scoutfs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct scoutfs_mount_options opts;
+#ifdef KC_BDEV_FILE_OPEN_BY_PATH
+	struct file *meta_bdev_file;
+#else
 	struct block_device *meta_bdev;
+#endif
 	struct scoutfs_sb_info *sbi;
 	struct inode *inode;
 	int ret;
@@ -527,6 +537,22 @@ static int scoutfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out;
 	}
 
+#ifdef KC_BDEV_FILE_OPEN_BY_PATH
+	/*
+	 * pass sbi as holder, since dev_mount already passes sb, which triggers a
+	 * WARN_ON because dev_mount also passes non-NULL hops. By passing sbi
+	 * here we just get a simple error in our test cases.
+	 */
+	meta_bdev_file = bdev_file_open_by_path(opts.metadev_path, SCOUTFS_META_BDEV_MODE, sbi, NULL);
+	if (IS_ERR(meta_bdev_file)) {
+		scoutfs_err(sb, "could not open metadev: error %ld",
+			    PTR_ERR(meta_bdev_file));
+		ret = PTR_ERR(meta_bdev_file);
+		goto out;
+	}
+	sbi->meta_bdev_file = meta_bdev_file;
+	sbi->meta_bdev = file_bdev(meta_bdev_file);
+#else
 #ifdef KC_BLKDEV_PUT_HOLDER_ARG
 	meta_bdev = blkdev_get_by_path(opts.metadev_path, SCOUTFS_META_BDEV_MODE, sb, NULL);
 #else
@@ -539,6 +565,8 @@ static int scoutfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out;
 	}
 	sbi->meta_bdev = meta_bdev;
+#endif
+
 	ret = set_blocksize(sbi->meta_bdev, SCOUTFS_BLOCK_SM_SIZE);
 	if (ret != 0) {
 		scoutfs_err(sb, "failed to set metadev blocksize, returned %d",
diff --git a/kmod/src/super.h b/kmod/src/super.h
index 45ec8450..3bb10ddb 100644
--- a/kmod/src/super.h
+++ b/kmod/src/super.h
@@ -42,6 +42,9 @@ struct scoutfs_sb_info {
 	u64 fmt_vers;
 
 	struct block_device *meta_bdev;
+#ifdef KC_BDEV_FILE_OPEN_BY_PATH
+	struct file *meta_bdev_file;
+#endif
 
 	spinlock_t next_ino_lock;