Merge tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull block handle updates from Christian Brauner:
 "Last cycle we changed opening of block devices, and opening a block
  device would return a bdev_handle. This allowed us to implement
  support for restricting and forbidding writes to mounted block
  devices. It was accompanied by converting and adding helpers to
  operate on bdev_handles instead of plain block devices.

  That was already a good step forward but ultimately it isn't necessary
  to have special purpose helpers for opening block devices internally
  that return a bdev_handle.

  Fundamentally, opening a block device internally should just be
  equivalent to opening files. So now all internal opens of block
  devices return files just as a userspace open would. Instead of
  introducing a separate indirection into bdev_open_by_*() via struct
  bdev_handle bdev_file_open_by_*() is made to just return a struct
  file. Opening and closing a block device just becomes equivalent to
  opening and closing a file.

  This all works well because internally we already have a pseudo fs for
  block devices and so opening block devices is simple. There's a few
  places where we needed to be careful such as during boot when the
  kernel is supposed to mount the rootfs directly without init doing it.
  Here we need to take care to ensure that we flush out any asynchronous
  file close. That's what we already do for opening, unpacking, and
  closing the initramfs. So nothing new here.

  The equivalence of opening and closing block devices to regular files
  is a win in and of itself. But it also has various other advantages.
  We can remove struct bdev_handle completely. Various low-level helpers
  are now private to the block layer. Other helpers were simply
  removable completely.

  A follow-up series that is already reviewed build on this and makes it
  possible to remove bdev->bd_inode and allows various clean ups of the
  buffer head code as well. All places where we stashed a bdev_handle
  now just stash a file and use simple accessors to get to the actual
  block device which was already the case for bdev_handle"

* tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  block: remove bdev_handle completely
  block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access
  bdev: remove bdev pointer from struct bdev_handle
  bdev: make struct bdev_handle private to the block layer
  bdev: make bdev_{release, open_by_dev}() private to block layer
  bdev: remove bdev_open_by_path()
  reiserfs: port block device access to file
  ocfs2: port block device access to file
  nfs: port block device access to files
  jfs: port block device access to file
  f2fs: port block device access to files
  ext4: port block device access to file
  erofs: port device access to file
  btrfs: port device access to file
  bcachefs: port block device access to file
  target: port block device access to file
  s390: port block device access to file
  nvme: port block device access to file
  block2mtd: port device access to files
  bcache: port block device access to files
  ...

5 files changed, 59 insertions, 56 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 6ae2329052c9..4e6afa89921f 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -300,7 +300,7 @@ struct cached_dev {
 	struct list_head	list;
 	struct bcache_device	disk;
 	struct block_device	*bdev;
-	struct bdev_handle	*bdev_handle;
+	struct file		*bdev_file;
 
 	struct cache_sb		sb;
 	struct cache_sb_disk	*sb_disk;
@@ -423,7 +423,7 @@ struct cache {
 
 	struct kobject		kobj;
 	struct block_device	*bdev;
-	struct bdev_handle	*bdev_handle;
+	struct file		*bdev_file;
 
 	struct task_struct	*alloc_thread;
 
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index dc3f50f69714..d00b3abab133 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1369,8 +1369,8 @@ static CLOSURE_CALLBACK(cached_dev_free)
 	if (dc->sb_disk)
 		put_page(virt_to_page(dc->sb_disk));
 
-	if (dc->bdev_handle)
-		bdev_release(dc->bdev_handle);
+	if (dc->bdev_file)
+		fput(dc->bdev_file);
 
 	wake_up(&unregister_wait);
 
@@ -1445,7 +1445,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
 /* Cached device - bcache superblock */
 
 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
-				 struct bdev_handle *bdev_handle,
+				 struct file *bdev_file,
 				 struct cached_dev *dc)
 {
 	const char *err = "cannot allocate memory";
@@ -1453,8 +1453,8 @@ static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 	int ret = -ENOMEM;
 
 	memcpy(&dc->sb, sb, sizeof(struct cache_sb));
-	dc->bdev_handle = bdev_handle;
-	dc->bdev = bdev_handle->bdev;
+	dc->bdev_file = bdev_file;
+	dc->bdev = file_bdev(bdev_file);
 	dc->sb_disk = sb_disk;
 
 	if (cached_dev_init(dc, sb->block_size << 9))
@@ -2218,8 +2218,8 @@ void bch_cache_release(struct kobject *kobj)
 	if (ca->sb_disk)
 		put_page(virt_to_page(ca->sb_disk));
 
-	if (ca->bdev_handle)
-		bdev_release(ca->bdev_handle);
+	if (ca->bdev_file)
+		fput(ca->bdev_file);
 
 	kfree(ca);
 	module_put(THIS_MODULE);
@@ -2339,18 +2339,18 @@ err_free:
 }
 
 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
-				struct bdev_handle *bdev_handle,
+				struct file *bdev_file,
 				struct cache *ca)
 {
 	const char *err = NULL; /* must be set for any error case */
 	int ret = 0;
 
 	memcpy(&ca->sb, sb, sizeof(struct cache_sb));
-	ca->bdev_handle = bdev_handle;
-	ca->bdev = bdev_handle->bdev;
+	ca->bdev_file = bdev_file;
+	ca->bdev = file_bdev(bdev_file);
 	ca->sb_disk = sb_disk;
 
-	if (bdev_max_discard_sectors((bdev_handle->bdev)))
+	if (bdev_max_discard_sectors(file_bdev(bdev_file)))
 		ca->discard = CACHE_DISCARD(&ca->sb);
 
 	ret = cache_alloc(ca);
@@ -2361,20 +2361,20 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 			err = "cache_alloc(): cache device is too small";
 		else
 			err = "cache_alloc(): unknown error";
-		pr_notice("error %pg: %s\n", bdev_handle->bdev, err);
+		pr_notice("error %pg: %s\n", file_bdev(bdev_file), err);
 		/*
 		 * If we failed here, it means ca->kobj is not initialized yet,
 		 * kobject_put() won't be called and there is no chance to
-		 * call bdev_release() to bdev in bch_cache_release(). So
-		 * we explicitly call bdev_release() here.
+		 * call fput() to bdev in bch_cache_release(). So
+		 * we explicitly call fput() on the block device here.
 		 */
-		bdev_release(bdev_handle);
+		fput(bdev_file);
 		return ret;
 	}
 
-	if (kobject_add(&ca->kobj, bdev_kobj(bdev_handle->bdev), "bcache")) {
+	if (kobject_add(&ca->kobj, bdev_kobj(file_bdev(bdev_file)), "bcache")) {
 		pr_notice("error %pg: error calling kobject_add\n",
-			  bdev_handle->bdev);
+			  file_bdev(bdev_file));
 		ret = -ENOMEM;
 		goto out;
 	}
@@ -2388,7 +2388,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 		goto out;
 	}
 
-	pr_info("registered cache device %pg\n", ca->bdev_handle->bdev);
+	pr_info("registered cache device %pg\n", file_bdev(ca->bdev_file));
 
 out:
 	kobject_put(&ca->kobj);
@@ -2446,7 +2446,7 @@ struct async_reg_args {
 	char *path;
 	struct cache_sb *sb;
 	struct cache_sb_disk *sb_disk;
-	struct bdev_handle *bdev_handle;
+	struct file *bdev_file;
 	void *holder;
 };
 
@@ -2457,7 +2457,7 @@ static void register_bdev_worker(struct work_struct *work)
 		container_of(work, struct async_reg_args, reg_work.work);
 
 	mutex_lock(&bch_register_lock);
-	if (register_bdev(args->sb, args->sb_disk, args->bdev_handle,
+	if (register_bdev(args->sb, args->sb_disk, args->bdev_file,
 			  args->holder) < 0)
 		fail = true;
 	mutex_unlock(&bch_register_lock);
@@ -2478,7 +2478,7 @@ static void register_cache_worker(struct work_struct *work)
 		container_of(work, struct async_reg_args, reg_work.work);
 
 	/* blkdev_put() will be called in bch_cache_release() */
-	if (register_cache(args->sb, args->sb_disk, args->bdev_handle,
+	if (register_cache(args->sb, args->sb_disk, args->bdev_file,
 			   args->holder))
 		fail = true;
 
@@ -2516,7 +2516,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	char *path = NULL;
 	struct cache_sb *sb;
 	struct cache_sb_disk *sb_disk;
-	struct bdev_handle *bdev_handle, *bdev_handle2;
+	struct file *bdev_file, *bdev_file2;
 	void *holder = NULL;
 	ssize_t ret;
 	bool async_registration = false;
@@ -2549,15 +2549,15 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
 	ret = -EINVAL;
 	err = "failed to open device";
-	bdev_handle = bdev_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
-	if (IS_ERR(bdev_handle))
+	bdev_file = bdev_file_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
+	if (IS_ERR(bdev_file))
 		goto out_free_sb;
 
 	err = "failed to set blocksize";
-	if (set_blocksize(bdev_handle->bdev, 4096))
+	if (set_blocksize(file_bdev(bdev_file), 4096))
 		goto out_blkdev_put;
 
-	err = read_super(sb, bdev_handle->bdev, &sb_disk);
+	err = read_super(sb, file_bdev(bdev_file), &sb_disk);
 	if (err)
 		goto out_blkdev_put;
 
@@ -2569,13 +2569,13 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	}
 
 	/* Now reopen in exclusive mode with proper holder */
-	bdev_handle2 = bdev_open_by_dev(bdev_handle->bdev->bd_dev,
+	bdev_file2 = bdev_file_open_by_dev(file_bdev(bdev_file)->bd_dev,
 			BLK_OPEN_READ | BLK_OPEN_WRITE, holder, NULL);
-	bdev_release(bdev_handle);
-	bdev_handle = bdev_handle2;
-	if (IS_ERR(bdev_handle)) {
-		ret = PTR_ERR(bdev_handle);
-		bdev_handle = NULL;
+	fput(bdev_file);
+	bdev_file = bdev_file2;
+	if (IS_ERR(bdev_file)) {
+		ret = PTR_ERR(bdev_file);
+		bdev_file = NULL;
 		if (ret == -EBUSY) {
 			dev_t dev;
 
@@ -2610,7 +2610,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 		args->path	= path;
 		args->sb	= sb;
 		args->sb_disk	= sb_disk;
-		args->bdev_handle	= bdev_handle;
+		args->bdev_file	= bdev_file;
 		args->holder	= holder;
 		register_device_async(args);
 		/* No wait and returns to user space */
@@ -2619,14 +2619,14 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
 	if (SB_IS_BDEV(sb)) {
 		mutex_lock(&bch_register_lock);
-		ret = register_bdev(sb, sb_disk, bdev_handle, holder);
+		ret = register_bdev(sb, sb_disk, bdev_file, holder);
 		mutex_unlock(&bch_register_lock);
 		/* blkdev_put() will be called in cached_dev_free() */
 		if (ret < 0)
 			goto out_free_sb;
 	} else {
 		/* blkdev_put() will be called in bch_cache_release() */
-		ret = register_cache(sb, sb_disk, bdev_handle, holder);
+		ret = register_cache(sb, sb_disk, bdev_file, holder);
 		if (ret)
 			goto out_free_sb;
 	}
@@ -2642,8 +2642,8 @@ out_free_holder:
 out_put_sb_page:
 	put_page(virt_to_page(sb_disk));
 out_blkdev_put:
-	if (bdev_handle)
-		bdev_release(bdev_handle);
+	if (bdev_file)
+		fput(bdev_file);
 out_free_sb:
 	kfree(sb);
 out_free_path:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8dcabf84d866..87de5b5682ad 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -726,7 +726,8 @@ static struct table_device *open_table_device(struct mapped_device *md,
 		dev_t dev, blk_mode_t mode)
 {
 	struct table_device *td;
-	struct bdev_handle *bdev_handle;
+	struct file *bdev_file;
+	struct block_device *bdev;
 	u64 part_off;
 	int r;
 
@@ -735,34 +736,36 @@ static struct table_device *open_table_device(struct mapped_device *md,
 		return ERR_PTR(-ENOMEM);
 	refcount_set(&td->count, 1);
 
-	bdev_handle = bdev_open_by_dev(dev, mode, _dm_claim_ptr, NULL);
-	if (IS_ERR(bdev_handle)) {
-		r = PTR_ERR(bdev_handle);
+	bdev_file = bdev_file_open_by_dev(dev, mode, _dm_claim_ptr, NULL);
+	if (IS_ERR(bdev_file)) {
+		r = PTR_ERR(bdev_file);
 		goto out_free_td;
 	}
 
+	bdev = file_bdev(bdev_file);
+
 	/*
 	 * We can be called before the dm disk is added.  In that case we can't
 	 * register the holder relation here.  It will be done once add_disk was
 	 * called.
 	 */
 	if (md->disk->slave_dir) {
-		r = bd_link_disk_holder(bdev_handle->bdev, md->disk);
+		r = bd_link_disk_holder(bdev, md->disk);
 		if (r)
 			goto out_blkdev_put;
 	}
 
 	td->dm_dev.mode = mode;
-	td->dm_dev.bdev = bdev_handle->bdev;
-	td->dm_dev.bdev_handle = bdev_handle;
-	td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev_handle->bdev, &part_off,
+	td->dm_dev.bdev = bdev;
+	td->dm_dev.bdev_file = bdev_file;
+	td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off,
 						NULL, NULL);
 	format_dev_t(td->dm_dev.name, dev);
 	list_add(&td->list, &md->table_devices);
 	return td;
 
 out_blkdev_put:
-	bdev_release(bdev_handle);
+	fput(bdev_file);
 out_free_td:
 	kfree(td);
 	return ERR_PTR(r);
@@ -775,7 +778,7 @@ static void close_table_device(struct table_device *td, struct mapped_device *md
 {
 	if (md->disk->slave_dir)
 		bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
-	bdev_release(td->dm_dev.bdev_handle);
+	fput(td->dm_dev.bdev_file);
 	put_dax(td->dm_dev.dax_dev);
 	list_del(&td->list);
 	kfree(td);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9e41a9aaba8b..3bf7eab94efd 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2582,7 +2582,7 @@ static void export_rdev(struct md_rdev *rdev, struct mddev *mddev)
 	if (test_bit(AutoDetected, &rdev->flags))
 		md_autodetect_dev(rdev->bdev->bd_dev);
 #endif
-	bdev_release(rdev->bdev_handle);
+	fput(rdev->bdev_file);
 	rdev->bdev = NULL;
 	kobject_put(&rdev->kobj);
 }
@@ -3777,16 +3777,16 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe
 	if (err)
 		goto out_clear_rdev;
 
-	rdev->bdev_handle = bdev_open_by_dev(newdev,
+	rdev->bdev_file = bdev_file_open_by_dev(newdev,
 			BLK_OPEN_READ | BLK_OPEN_WRITE,
 			super_format == -2 ? &claim_rdev : rdev, NULL);
-	if (IS_ERR(rdev->bdev_handle)) {
+	if (IS_ERR(rdev->bdev_file)) {
 		pr_warn("md: could not open device unknown-block(%u,%u).\n",
 			MAJOR(newdev), MINOR(newdev));
-		err = PTR_ERR(rdev->bdev_handle);
+		err = PTR_ERR(rdev->bdev_file);
 		goto out_clear_rdev;
 	}
-	rdev->bdev = rdev->bdev_handle->bdev;
+	rdev->bdev = file_bdev(rdev->bdev_file);
 
 	kobject_init(&rdev->kobj, &rdev_ktype);
 
@@ -3817,7 +3817,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe
 	return rdev;
 
 out_blkdev_put:
-	bdev_release(rdev->bdev_handle);
+	fput(rdev->bdev_file);
 out_clear_rdev:
 	md_rdev_clear(rdev);
 out_free_rdev:
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 8d881cc59799..a079ee9b6190 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -59,7 +59,7 @@ struct md_rdev {
 	 */
 	struct block_device *meta_bdev;
 	struct block_device *bdev;	/* block device handle */
-	struct bdev_handle *bdev_handle;	/* Handle from open for bdev */
+	struct file *bdev_file;		/* Handle from open for bdev */
 
 	struct page	*sb_page, *bb_page;
 	int		sb_loaded;