Merge series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@kernel.org

Pull block devices as files from Christian Brauner:

This opens block devices as files. Instead of introducing a separate
indirection into bdev_open_by_*() vis struct bdev_handle we can just
make bdev_file_open_by_*() return a struct file. Opening and closing a
block device from setup_bdev_super() and in all other places just
becomes equivalent to opening and closing a file.

This has held up in xfstests and in blktests so far and it seems stable
and clean. The equivalence of opening and closing block devices to
regular files is a win in and of itself imho. Added to that is the
ability to do away with struct bdev_handle completely and make various
low-level helpers private to the block layer.

All places were we currently stash a struct bdev_handle we just stash a
file and use an accessor such as file_bdev() akin to I_BDEV() to get to
the block device.

It's now also possible to use file->f_mapping as a replacement for
bdev->bd_inode->i_mapping and file->f_inode or file->f_mapping->host as
an alternative to bdev->bd_inode allowing us to significantly reduce or
even fully remove bdev->bd_inode in follow-up patches.

In addition, we could get rid of sb->s_bdev and various other places
that stash the block device directly and instead stash the block device
file. Again, this is follow-up work if we want this.

* series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@kernel.org: (35 commits)
  file: add alloc_file_pseudo_noaccount()
  file: prepare for new helper
  init: flush async file closing
  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
  ...

Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 16 insertions, 16 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 4d7efefa98c5..1bde1281d514 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -213,7 +213,7 @@ struct o2hb_region {
 	unsigned int		hr_num_pages;
 
 	struct page             **hr_slot_data;
-	struct bdev_handle	*hr_bdev_handle;
+	struct file		*hr_bdev_file;
 	struct o2hb_disk_slot	*hr_slots;
 
 	/* live node map of this region */
@@ -263,7 +263,7 @@ struct o2hb_region {
 
 static inline struct block_device *reg_bdev(struct o2hb_region *reg)
 {
-	return reg->hr_bdev_handle ? reg->hr_bdev_handle->bdev : NULL;
+	return reg->hr_bdev_file ? file_bdev(reg->hr_bdev_file) : NULL;
 }
 
 struct o2hb_bio_wait_ctxt {
@@ -1509,8 +1509,8 @@ static void o2hb_region_release(struct config_item *item)
 		kfree(reg->hr_slot_data);
 	}
 
-	if (reg->hr_bdev_handle)
-		bdev_release(reg->hr_bdev_handle);
+	if (reg->hr_bdev_file)
+		fput(reg->hr_bdev_file);
 
 	kfree(reg->hr_slots);
 
@@ -1569,7 +1569,7 @@ static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
 	unsigned long block_bytes;
 	unsigned int block_bits;
 
-	if (reg->hr_bdev_handle)
+	if (reg->hr_bdev_file)
 		return -EINVAL;
 
 	status = o2hb_read_block_input(reg, page, &block_bytes,
@@ -1598,7 +1598,7 @@ static ssize_t o2hb_region_start_block_store(struct config_item *item,
 	char *p = (char *)page;
 	ssize_t ret;
 
-	if (reg->hr_bdev_handle)
+	if (reg->hr_bdev_file)
 		return -EINVAL;
 
 	ret = kstrtoull(p, 0, &tmp);
@@ -1623,7 +1623,7 @@ static ssize_t o2hb_region_blocks_store(struct config_item *item,
 	unsigned long tmp;
 	char *p = (char *)page;
 
-	if (reg->hr_bdev_handle)
+	if (reg->hr_bdev_file)
 		return -EINVAL;
 
 	tmp = simple_strtoul(p, &p, 0);
@@ -1642,7 +1642,7 @@ static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
 {
 	unsigned int ret = 0;
 
-	if (to_o2hb_region(item)->hr_bdev_handle)
+	if (to_o2hb_region(item)->hr_bdev_file)
 		ret = sprintf(page, "%pg\n", reg_bdev(to_o2hb_region(item)));
 
 	return ret;
@@ -1753,7 +1753,7 @@ out:
 }
 
 /*
- * this is acting as commit; we set up all of hr_bdev_handle and hr_task or
+ * this is acting as commit; we set up all of hr_bdev_file and hr_task or
  * nothing
  */
 static ssize_t o2hb_region_dev_store(struct config_item *item,
@@ -1769,7 +1769,7 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 	ssize_t ret = -EINVAL;
 	int live_threshold;
 
-	if (reg->hr_bdev_handle)
+	if (reg->hr_bdev_file)
 		goto out;
 
 	/* We can't heartbeat without having had our node number
@@ -1795,11 +1795,11 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 	if (!S_ISBLK(f.file->f_mapping->host->i_mode))
 		goto out2;
 
-	reg->hr_bdev_handle = bdev_open_by_dev(f.file->f_mapping->host->i_rdev,
+	reg->hr_bdev_file = bdev_file_open_by_dev(f.file->f_mapping->host->i_rdev,
 			BLK_OPEN_WRITE | BLK_OPEN_READ, NULL, NULL);
-	if (IS_ERR(reg->hr_bdev_handle)) {
-		ret = PTR_ERR(reg->hr_bdev_handle);
-		reg->hr_bdev_handle = NULL;
+	if (IS_ERR(reg->hr_bdev_file)) {
+		ret = PTR_ERR(reg->hr_bdev_file);
+		reg->hr_bdev_file = NULL;
 		goto out2;
 	}
 
@@ -1903,8 +1903,8 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 
 out3:
 	if (ret < 0) {
-		bdev_release(reg->hr_bdev_handle);
-		reg->hr_bdev_handle = NULL;
+		fput(reg->hr_bdev_file);
+		reg->hr_bdev_file = NULL;
 	}
 out2:
 	fdput(f);