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
  ...

include/linux/blkdev.h

@@ -24,6 +24,7 @@
 #include <linux/sbitmap.h>
 #include <linux/uuid.h>
 #include <linux/xarray.h>
+#include <linux/file.h>
 
 struct module;
 struct request_queue;
@@ -1474,26 +1475,20 @@ extern const struct blk_holder_ops fs_holder_ops;
 	(BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES | \
 	 (((flags) & SB_RDONLY) ? 0 : BLK_OPEN_WRITE))
 
-struct bdev_handle {
-	struct block_device *bdev;
-	void *holder;
-	blk_mode_t mode;
-};
-
-struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
+struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
 		const struct blk_holder_ops *hops);
-struct bdev_handle *bdev_open_by_path(const char *path, blk_mode_t mode,
+struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
 		void *holder, const struct blk_holder_ops *hops);
 int bd_prepare_to_claim(struct block_device *bdev, void *holder,
 		const struct blk_holder_ops *hops);
 void bd_abort_claiming(struct block_device *bdev, void *holder);
-void bdev_release(struct bdev_handle *handle);
 
 /* just for blk-cgroup, don't use elsewhere */
 struct block_device *blkdev_get_no_open(dev_t dev);
 void blkdev_put_no_open(struct block_device *bdev);
 
 struct block_device *I_BDEV(struct inode *inode);
+struct block_device *file_bdev(struct file *bdev_file);
 
 #ifdef CONFIG_BLOCK
 void invalidate_bdev(struct block_device *bdev);

include/linux/device-mapper.h

@@ -165,7 +165,7 @@ void dm_error(const char *message);
 
 struct dm_dev {
 	struct block_device *bdev;
-	struct bdev_handle *bdev_handle;
+	struct file *bdev_file;
 	struct dax_device *dax_dev;
 	blk_mode_t mode;
 	char name[16];

include/linux/file.h

@@ -24,6 +24,8 @@ struct inode;
 struct path;
 extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
 	const char *, int flags, const struct file_operations *);
+extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *,
+	const char *, int flags, const struct file_operations *);
 extern struct file *alloc_file_clone(struct file *, int flags,
 	const struct file_operations *);
 

include/linux/fs.h

@@ -1237,8 +1237,8 @@ struct super_block {
 #endif
 	struct hlist_bl_head	s_roots;	/* alternate root dentries for NFS */
 	struct list_head	s_mounts;	/* list of mounts; _not_ for fs use */
-	struct block_device	*s_bdev;
-	struct bdev_handle	*s_bdev_handle;
+	struct block_device	*s_bdev;	/* can go away once we use an accessor for @s_bdev_file */
+	struct file		*s_bdev_file;
 	struct backing_dev_info *s_bdi;
 	struct mtd_info		*s_mtd;
 	struct hlist_node	s_instances;

include/linux/pktcdvd.h

@@ -154,9 +154,9 @@ struct packet_stacked_data
 
 struct pktcdvd_device
 {
-	struct bdev_handle	*bdev_handle;	/* dev attached */
+	struct file		*bdev_file;	/* dev attached */
 	/* handle acquired for bdev during pkt_open_dev() */
-	struct bdev_handle	*open_bdev_handle;
+	struct file		*f_open_bdev;
 	dev_t			pkt_dev;	/* our dev */
 	struct packet_settings	settings;
 	struct packet_stats	stats;

include/linux/swap.h

@@ -298,7 +298,7 @@ struct swap_info_struct {
 	unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
 	struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
 	struct rb_root swap_extent_root;/* root of the swap extent rbtree */
-	struct bdev_handle *bdev_handle;/* open handle of the bdev */
+	struct file *bdev_file;		/* open handle of the bdev */
 	struct block_device *bdev;	/* swap device or bdev of swap file */
 	struct file *swap_file;		/* seldom referenced */
 	unsigned int old_block_size;	/* seldom referenced */