diff mbox series

[23/45] block: remove i_bdev

Message ID 20201124132751.3747337-24-hch@lst.de (mailing list archive)
State New
Headers show
Series [01/45] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats | expand

Commit Message

Christoph Hellwig Nov. 24, 2020, 1:27 p.m. UTC
Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case).  This means that
we not don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c                                |   3 +-
 drivers/block/loop.c                         |   8 +-
 drivers/md/bcache/super.c                    |  20 +-
 drivers/md/dm-table.c                        |   9 +-
 drivers/mtd/mtdsuper.c                       |  17 +-
 drivers/target/target_core_file.c            |   6 +-
 drivers/usb/gadget/function/storage_common.c |   8 +-
 fs/block_dev.c                               | 195 +++++--------------
 fs/btrfs/volumes.c                           |  13 +-
 fs/inode.c                                   |   3 -
 fs/internal.h                                |   7 +-
 fs/io_uring.c                                |  10 +-
 fs/pipe.c                                    |   5 +-
 fs/quota/quota.c                             |  19 +-
 fs/statfs.c                                  |   2 +-
 fs/super.c                                   |  37 ++--
 include/linux/blkdev.h                       |   2 +-
 include/linux/fs.h                           |   1 -
 18 files changed, 114 insertions(+), 251 deletions(-)

Comments

Tejun Heo Nov. 24, 2020, 7:37 p.m. UTC | #1
On Tue, Nov 24, 2020 at 02:27:29PM +0100, Christoph Hellwig wrote:
> Switch the block device lookup interfaces to directly work with a dev_t
> so that struct block_device references are only acquired by the
> blkdev_get variants (and the blk-cgroup special case).  This means that
> we not don't need an extra reference in the inode and can generally
     ^
     now
> simplify handling of struct block_device to keep the lookups contained
> in the core block layer code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
...
> @@ -1689,14 +1599,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
>  	if ((filp->f_flags & O_ACCMODE) == 3)
>  		filp->f_mode |= FMODE_WRITE_IOCTL;
>  
> -	bdev = bd_acquire(inode);
> -	if (bdev == NULL)
> -		return -ENOMEM;
> -
> +	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
> +	if (IS_ERR(bdev))
> +		return PTR_ERR(bdev);
>  	filp->f_mapping = bdev->bd_inode->i_mapping;
>  	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
> -
> -	return blkdev_get(bdev, filp->f_mode, filp);
> +	return 0;
>  }

I was wondering whether losing the stale bdev flushing in bd_acquire() would
cause user-visible behavior changes but can't see how it would given that
userland has no way of holding onto a specific instance of block inode.
Maybe it's something worth mentioning in the commit message?

Other than that, for the block part:

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.
Christoph Hellwig Nov. 25, 2020, 4:29 p.m. UTC | #2
On Tue, Nov 24, 2020 at 02:37:05PM -0500, Tejun Heo wrote:
> On Tue, Nov 24, 2020 at 02:27:29PM +0100, Christoph Hellwig wrote:
> > Switch the block device lookup interfaces to directly work with a dev_t
> > so that struct block_device references are only acquired by the
> > blkdev_get variants (and the blk-cgroup special case).  This means that
> > we not don't need an extra reference in the inode and can generally
>      ^
>      now
> > simplify handling of struct block_device to keep the lookups contained
> > in the core block layer code.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> ...
> > @@ -1689,14 +1599,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
> >  	if ((filp->f_flags & O_ACCMODE) == 3)
> >  		filp->f_mode |= FMODE_WRITE_IOCTL;
> >  
> > -	bdev = bd_acquire(inode);
> > -	if (bdev == NULL)
> > -		return -ENOMEM;
> > -
> > +	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
> > +	if (IS_ERR(bdev))
> > +		return PTR_ERR(bdev);
> >  	filp->f_mapping = bdev->bd_inode->i_mapping;
> >  	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
> > -
> > -	return blkdev_get(bdev, filp->f_mode, filp);
> > +	return 0;
> >  }
> 
> I was wondering whether losing the stale bdev flushing in bd_acquire() would
> cause user-visible behavior changes but can't see how it would given that
> userland has no way of holding onto a specific instance of block inode.
> Maybe it's something worth mentioning in the commit message?

With stale bdev flushing do you mean the call to bd_forget if
i_bdev exists but is unhashed?  It doesn't actually flush anything but
just detaches the old bdev from the inode so that the new one can be
attached.  That problem goes away by definition if we don't attach
the bdev to the inode.
Tejun Heo Nov. 25, 2020, 8:19 p.m. UTC | #3
Hello,

On Wed, Nov 25, 2020 at 05:29:26PM +0100, Christoph Hellwig wrote:
> > I was wondering whether losing the stale bdev flushing in bd_acquire() would
> > cause user-visible behavior changes but can't see how it would given that
> > userland has no way of holding onto a specific instance of block inode.
> > Maybe it's something worth mentioning in the commit message?
> 
> With stale bdev flushing do you mean the call to bd_forget if
> i_bdev exists but is unhashed?  It doesn't actually flush anything but

Yeah.

> just detaches the old bdev from the inode so that the new one can be
> attached.  That problem goes away by definition if we don't attach
> the bdev to the inode.

Yeah, I think so. Was just wondering whether the problem actually goes away.

Thanks.
diff mbox series

Patch

diff --git a/block/ioctl.c b/block/ioctl.c
index 0c09bb7a6ff35f..a6d8171221c7dc 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -590,8 +590,7 @@  long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 {
 	int ret;
 	void __user *argp = compat_ptr(arg);
-	struct inode *inode = file->f_mapping->host;
-	struct block_device *bdev = inode->i_bdev;
+	struct block_device *bdev = I_BDEV(file->f_mapping->host);
 	struct gendisk *disk = bdev->bd_disk;
 	fmode_t mode = file->f_mode;
 	loff_t size;
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b42c728620c9e4..26c7aafba7c5f8 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -675,10 +675,10 @@  static int loop_validate_file(struct file *file, struct block_device *bdev)
 	while (is_loop_device(f)) {
 		struct loop_device *l;
 
-		if (f->f_mapping->host->i_bdev == bdev)
+		if (f->f_mapping->host->i_rdev == bdev->bd_dev)
 			return -EBADF;
 
-		l = f->f_mapping->host->i_bdev->bd_disk->private_data;
+		l = I_BDEV(f->f_mapping->host)->bd_disk->private_data;
 		if (l->lo_state != Lo_bound) {
 			return -EINVAL;
 		}
@@ -885,9 +885,7 @@  static void loop_config_discard(struct loop_device *lo)
 	 * file-backed loop devices: discarded regions read back as zero.
 	 */
 	if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) {
-		struct request_queue *backingq;
-
-		backingq = bdev_get_queue(inode->i_bdev);
+		struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
 
 		max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
 		granularity = backingq->limits.discard_granularity ?:
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a6a5e21e4fd136..c55d3c58a7ef55 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2380,38 +2380,38 @@  kobj_attribute_write(register,		register_bcache);
 kobj_attribute_write(register_quiet,	register_bcache);
 kobj_attribute_write(pendings_cleanup,	bch_pending_bdevs_cleanup);
 
-static bool bch_is_open_backing(struct block_device *bdev)
+static bool bch_is_open_backing(dev_t dev)
 {
 	struct cache_set *c, *tc;
 	struct cached_dev *dc, *t;
 
 	list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
 		list_for_each_entry_safe(dc, t, &c->cached_devs, list)
-			if (dc->bdev == bdev)
+			if (dc->bdev->bd_dev == dev)
 				return true;
 	list_for_each_entry_safe(dc, t, &uncached_devices, list)
-		if (dc->bdev == bdev)
+		if (dc->bdev->bd_dev == dev)
 			return true;
 	return false;
 }
 
-static bool bch_is_open_cache(struct block_device *bdev)
+static bool bch_is_open_cache(dev_t dev)
 {
 	struct cache_set *c, *tc;
 
 	list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
 		struct cache *ca = c->cache;
 
-		if (ca->bdev == bdev)
+		if (ca->bdev->bd_dev == dev)
 			return true;
 	}
 
 	return false;
 }
 
-static bool bch_is_open(struct block_device *bdev)
+static bool bch_is_open(dev_t dev)
 {
-	return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
+	return bch_is_open_cache(dev) || bch_is_open_backing(dev);
 }
 
 struct async_reg_args {
@@ -2535,9 +2535,11 @@  static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 				  sb);
 	if (IS_ERR(bdev)) {
 		if (bdev == ERR_PTR(-EBUSY)) {
-			bdev = lookup_bdev(strim(path));
+			dev_t dev;
+
 			mutex_lock(&bch_register_lock);
-			if (!IS_ERR(bdev) && bch_is_open(bdev))
+			if (lookup_bdev(strim(path), &dev) == 0 &&
+			    bch_is_open(dev))
 				err = "device already registered";
 			else
 				err = "device busy";
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index ce543b761be7b2..dea67772171053 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -348,16 +348,9 @@  static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 dev_t dm_get_dev_t(const char *path)
 {
 	dev_t dev;
-	struct block_device *bdev;
 
-	bdev = lookup_bdev(path);
-	if (IS_ERR(bdev))
+	if (lookup_bdev(path, &dev))
 		dev = name_to_dev_t(path);
-	else {
-		dev = bdev->bd_dev;
-		bdput(bdev);
-	}
-
 	return dev;
 }
 EXPORT_SYMBOL_GPL(dm_get_dev_t);
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index c3e2098372f2e5..38b6aa849c6383 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -120,8 +120,8 @@  int get_tree_mtd(struct fs_context *fc,
 				struct fs_context *fc))
 {
 #ifdef CONFIG_BLOCK
-	struct block_device *bdev;
-	int ret, major;
+	dev_t dev;
+	int ret;
 #endif
 	int mtdnr;
 
@@ -169,20 +169,15 @@  int get_tree_mtd(struct fs_context *fc,
 	/* try the old way - the hack where we allowed users to mount
 	 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
 	 */
-	bdev = lookup_bdev(fc->source);
-	if (IS_ERR(bdev)) {
-		ret = PTR_ERR(bdev);
+	ret = lookup_bdev(fc->source, &dev);
+	if (ret) {
 		errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
 		return ret;
 	}
 	pr_debug("MTDSB: lookup_bdev() returned 0\n");
 
-	major = MAJOR(bdev->bd_dev);
-	mtdnr = MINOR(bdev->bd_dev);
-	bdput(bdev);
-
-	if (major == MTD_BLOCK_MAJOR)
-		return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
+	if (MAJOR(dev) == MTD_BLOCK_MAJOR)
+		return mtd_get_sb_by_nr(fc, MINOR(dev), fill_super);
 
 #endif /* CONFIG_BLOCK */
 
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 7143d03f0e027e..b0cb5b95e892d3 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -133,10 +133,10 @@  static int fd_configure_device(struct se_device *dev)
 	 */
 	inode = file->f_mapping->host;
 	if (S_ISBLK(inode->i_mode)) {
-		struct request_queue *q = bdev_get_queue(inode->i_bdev);
+		struct request_queue *q = bdev_get_queue(I_BDEV(inode));
 		unsigned long long dev_size;
 
-		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
+		fd_dev->fd_block_size = bdev_logical_block_size(I_BDEV(inode));
 		/*
 		 * Determine the number of bytes from i_size_read() minus
 		 * one (1) logical sector from underlying struct block_device
@@ -559,7 +559,7 @@  fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 
 	if (S_ISBLK(inode->i_mode)) {
 		/* The backend is block device, use discard */
-		struct block_device *bdev = inode->i_bdev;
+		struct block_device *bdev = I_BDEV(inode);
 		struct se_device *dev = cmd->se_dev;
 
 		ret = blkdev_issue_discard(bdev,
diff --git a/drivers/usb/gadget/function/storage_common.c b/drivers/usb/gadget/function/storage_common.c
index f7e6c42558eb76..b859a158a4140e 100644
--- a/drivers/usb/gadget/function/storage_common.c
+++ b/drivers/usb/gadget/function/storage_common.c
@@ -204,7 +204,7 @@  int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (!(filp->f_mode & FMODE_WRITE))
 		ro = 1;
 
-	inode = file_inode(filp);
+	inode = filp->f_mapping->host;
 	if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 		LINFO(curlun, "invalid file type: %s\n", filename);
 		goto out;
@@ -221,7 +221,7 @@  int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (!(filp->f_mode & FMODE_CAN_WRITE))
 		ro = 1;
 
-	size = i_size_read(inode->i_mapping->host);
+	size = i_size_read(inode);
 	if (size < 0) {
 		LINFO(curlun, "unable to find file size: %s\n", filename);
 		rc = (int) size;
@@ -231,8 +231,8 @@  int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 	if (curlun->cdrom) {
 		blksize = 2048;
 		blkbits = 11;
-	} else if (inode->i_bdev) {
-		blksize = bdev_logical_block_size(inode->i_bdev);
+	} else if (S_ISBLK(inode->i_mode)) {
+		blksize = bdev_logical_block_size(I_BDEV(inode));
 		blkbits = blksize_bits(blksize);
 	} else {
 		blksize = 512;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1e35faf6dad42c..c0d1e8248ffe23 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -883,7 +883,6 @@  static struct block_device *bdget(dev_t dev)
 		bdev->bd_dev = dev;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
-		inode->i_bdev = bdev;
 		inode->i_data.a_ops = &def_blk_aops;
 		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
 		unlock_new_inode(inode);
@@ -924,67 +923,8 @@  void bdput(struct block_device *bdev)
 {
 	iput(bdev->bd_inode);
 }
-
 EXPORT_SYMBOL(bdput);
  
-static struct block_device *bd_acquire(struct inode *inode)
-{
-	struct block_device *bdev;
-
-	spin_lock(&bdev_lock);
-	bdev = inode->i_bdev;
-	if (bdev && !inode_unhashed(bdev->bd_inode)) {
-		bdgrab(bdev);
-		spin_unlock(&bdev_lock);
-		return bdev;
-	}
-	spin_unlock(&bdev_lock);
-
-	/*
-	 * i_bdev references block device inode that was already shut down
-	 * (corresponding device got removed).  Remove the reference and look
-	 * up block device inode again just in case new device got
-	 * reestablished under the same device number.
-	 */
-	if (bdev)
-		bd_forget(inode);
-
-	bdev = bdget(inode->i_rdev);
-	if (bdev) {
-		spin_lock(&bdev_lock);
-		if (!inode->i_bdev) {
-			/*
-			 * We take an additional reference to bd_inode,
-			 * and it's released in clear_inode() of inode.
-			 * So, we can access it via ->i_mapping always
-			 * without igrab().
-			 */
-			bdgrab(bdev);
-			inode->i_bdev = bdev;
-			inode->i_mapping = bdev->bd_inode->i_mapping;
-		}
-		spin_unlock(&bdev_lock);
-	}
-	return bdev;
-}
-
-/* Call when you free inode */
-
-void bd_forget(struct inode *inode)
-{
-	struct block_device *bdev = NULL;
-
-	spin_lock(&bdev_lock);
-	if (!sb_is_blkdev_sb(inode->i_sb))
-		bdev = inode->i_bdev;
-	inode->i_bdev = NULL;
-	inode->i_mapping = &inode->i_data;
-	spin_unlock(&bdev_lock);
-
-	if (bdev)
-		bdput(bdev);
-}
-
 /**
  * bd_may_claim - test whether a block device can be claimed
  * @bdev: block device of interest
@@ -1492,38 +1432,45 @@  static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
 }
 
 /**
- * blkdev_get - open a block device
- * @bdev: block_device to open
+ * blkdev_get_by_dev - open a block device by device number
+ * @dev: device number of block device to open
  * @mode: FMODE_* mask
  * @holder: exclusive holder identifier
  *
- * Open @bdev with @mode.  If @mode includes %FMODE_EXCL, @bdev is
- * open with exclusive access.  Specifying %FMODE_EXCL with %NULL
- * @holder is invalid.  Exclusive opens may nest for the same @holder.
+ * Open the block device described by device number @dev.  If @mode includes
+ * If @mode includes %FMODE_EXCL, the block device is opened with exclusive
+ * access.  Specifying %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive
+ * opens may nest for the same @holder.
  *
- * On success, the reference count of @bdev is unchanged.  On failure,
- * @bdev is put.
+ * Use this interface ONLY if you really do not have anything better - i.e. when
+ * you are behind a truly sucky interface and all you are given is a device
+ * number.  Everything else should use blkdev_get_by_path().
  *
  * CONTEXT:
  * Might sleep.
  *
  * RETURNS:
- * 0 on success, -errno on failure.
+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
-static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 {
 	struct block_device *claiming;
 	bool unblock_events = true;
+	struct block_device *bdev;
 	struct gendisk *disk;
 	int partno;
 	int ret;
 
 	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
-			imajor(bdev->bd_inode), iminor(bdev->bd_inode),
+			MAJOR(dev), MINOR(dev),
 			((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
 			((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
 	if (ret)
-		goto bdput;
+		return ERR_PTR(ret);
+
+	bdev = bdget(dev);
+	if (!bdev)
+		return ERR_PTR(-ENOMEM);
 
 	/*
 	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
@@ -1584,10 +1531,13 @@  static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 	if (ret == -ERESTARTSYS)
 		goto retry;
 bdput:
-	if (ret)
+	if (ret) {
 		bdput(bdev);
-	return ret;
+		return ERR_PTR(ret);
+	}
+	return bdev;
 }
+EXPORT_SYMBOL(blkdev_get_by_dev);
 
 /**
  * blkdev_get_by_path - open a block device by name
@@ -1595,32 +1545,31 @@  static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
  * @mode: FMODE_* mask
  * @holder: exclusive holder identifier
  *
- * Open the blockdevice described by the device file at @path.  @mode
- * and @holder are identical to blkdev_get().
+ * Open the block device described by the device file at &path.
  *
- * On success, the returned block_device has reference count of one.
+ * If @mode includes %FMODE_EXCL, the block device is opened with exclusive
+ * access.  Specifying %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive
+ * opens may nest for the same @holder.
  *
  * CONTEXT:
  * Might sleep.
  *
  * RETURNS:
- * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 					void *holder)
 {
 	struct block_device *bdev;
-	int err;
-
-	bdev = lookup_bdev(path);
-	if (IS_ERR(bdev))
-		return bdev;
+	dev_t dev;
+	int error;
 
-	err = blkdev_get(bdev, mode, holder);
-	if (err)
-		return ERR_PTR(err);
+	error = lookup_bdev(path, &dev);
+	if (error)
+		return ERR_PTR(error);
 
-	if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+	bdev = blkdev_get_by_dev(dev, mode, holder);
+	if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
 		blkdev_put(bdev, mode);
 		return ERR_PTR(-EACCES);
 	}
@@ -1629,45 +1578,6 @@  struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 }
 EXPORT_SYMBOL(blkdev_get_by_path);
 
-/**
- * blkdev_get_by_dev - open a block device by device number
- * @dev: device number of block device to open
- * @mode: FMODE_* mask
- * @holder: exclusive holder identifier
- *
- * Open the blockdevice described by device number @dev.  @mode and
- * @holder are identical to blkdev_get().
- *
- * Use it ONLY if you really do not have anything better - i.e. when
- * you are behind a truly sucky interface and all you are given is a
- * device number.  _Never_ to be used for internal purposes.  If you
- * ever need it - reconsider your API.
- *
- * On success, the returned block_device has reference count of one.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * Pointer to block_device on success, ERR_PTR(-errno) on failure.
- */
-struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
-{
-	struct block_device *bdev;
-	int err;
-
-	bdev = bdget(dev);
-	if (!bdev)
-		return ERR_PTR(-ENOMEM);
-
-	err = blkdev_get(bdev, mode, holder);
-	if (err)
-		return ERR_PTR(err);
-
-	return bdev;
-}
-EXPORT_SYMBOL(blkdev_get_by_dev);
-
 static int blkdev_open(struct inode * inode, struct file * filp)
 {
 	struct block_device *bdev;
@@ -1689,14 +1599,12 @@  static int blkdev_open(struct inode * inode, struct file * filp)
 	if ((filp->f_flags & O_ACCMODE) == 3)
 		filp->f_mode |= FMODE_WRITE_IOCTL;
 
-	bdev = bd_acquire(inode);
-	if (bdev == NULL)
-		return -ENOMEM;
-
+	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
 	filp->f_mapping = bdev->bd_inode->i_mapping;
 	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
-
-	return blkdev_get(bdev, filp->f_mode, filp);
+	return 0;
 }
 
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@@ -2003,37 +1911,32 @@  const struct file_operations def_blk_fops = {
  * namespace if possible and return it.  Return ERR_PTR(error)
  * otherwise.
  */
-struct block_device *lookup_bdev(const char *pathname)
+int lookup_bdev(const char *pathname, dev_t *dev)
 {
-	struct block_device *bdev;
 	struct inode *inode;
 	struct path path;
 	int error;
 
 	if (!pathname || !*pathname)
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
 	error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 	if (error)
-		return ERR_PTR(error);
+		return error;
 
 	inode = d_backing_inode(path.dentry);
 	error = -ENOTBLK;
 	if (!S_ISBLK(inode->i_mode))
-		goto fail;
+		goto out_path_put;
 	error = -EACCES;
 	if (!may_open_dev(&path))
-		goto fail;
-	error = -ENOMEM;
-	bdev = bd_acquire(inode);
-	if (!bdev)
-		goto fail;
-out:
+		goto out_path_put;
+
+	*dev = inode->i_rdev;
+	error = 0;
+out_path_put:
 	path_put(&path);
-	return bdev;
-fail:
-	bdev = ERR_PTR(error);
-	goto out;
+	return error;
 }
 EXPORT_SYMBOL(lookup_bdev);
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a6406b3b8c2b4f..fbc4b58228f784 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -929,16 +929,16 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 		 * make sure it's the same device if the device is mounted
 		 */
 		if (device->bdev) {
-			struct block_device *path_bdev;
+			int error;
+			dev_t path_dev;
 
-			path_bdev = lookup_bdev(path);
-			if (IS_ERR(path_bdev)) {
+			error = lookup_bdev(path, &path_dev);
+			if (error) {
 				mutex_unlock(&fs_devices->device_list_mutex);
-				return ERR_CAST(path_bdev);
+				return ERR_PTR(error);
 			}
 
-			if (device->bdev != path_bdev) {
-				bdput(path_bdev);
+			if (device->bdev->bd_dev != path_dev) {
 				mutex_unlock(&fs_devices->device_list_mutex);
 				btrfs_warn_in_rcu(device->fs_info,
 	"duplicate device %s devid %llu generation %llu scanned by %s (%d)",
@@ -947,7 +947,6 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 						  task_pid_nr(current));
 				return ERR_PTR(-EEXIST);
 			}
-			bdput(path_bdev);
 			btrfs_info_in_rcu(device->fs_info,
 	"devid %llu device path %s changed to %s scanned by %s (%d)",
 					  devid, rcu_str_deref(device->name),
diff --git a/fs/inode.c b/fs/inode.c
index 9d78c37b00b817..cb008acf0efdb8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -155,7 +155,6 @@  int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_bytes = 0;
 	inode->i_generation = 0;
 	inode->i_pipe = NULL;
-	inode->i_bdev = NULL;
 	inode->i_cdev = NULL;
 	inode->i_link = NULL;
 	inode->i_dir_seq = 0;
@@ -580,8 +579,6 @@  static void evict(struct inode *inode)
 		truncate_inode_pages_final(&inode->i_data);
 		clear_inode(inode);
 	}
-	if (S_ISBLK(inode->i_mode) && inode->i_bdev)
-		bd_forget(inode);
 	if (S_ISCHR(inode->i_mode) && inode->i_cdev)
 		cd_forget(inode);
 
diff --git a/fs/internal.h b/fs/internal.h
index 47be21dfeebef5..53f890446e7508 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -25,7 +25,6 @@  extern void __init bdev_cache_init(void);
 extern int __sync_blockdev(struct block_device *bdev, int wait);
 void iterate_bdevs(void (*)(struct block_device *, void *), void *);
 void emergency_thaw_bdev(struct super_block *sb);
-void bd_forget(struct inode *inode);
 #else
 static inline void bdev_cache_init(void)
 {
@@ -43,9 +42,6 @@  static inline int emergency_thaw_bdev(struct super_block *sb)
 {
 	return 0;
 }
-static inline void bd_forget(struct inode *inode)
-{
-}
 #endif /* CONFIG_BLOCK */
 
 /*
@@ -114,8 +110,7 @@  extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
  */
 extern int reconfigure_super(struct fs_context *);
 extern bool trylock_super(struct super_block *sb);
-struct super_block *__get_super(struct block_device *bdev, bool excl);
-extern struct super_block *user_get_super(dev_t);
+struct super_block *user_get_super(dev_t, bool excl);
 void put_super(struct super_block *sb);
 extern bool mount_capable(struct fs_context *);
 
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4ead291b2976f3..8f13c0417f940c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2716,11 +2716,7 @@  static struct file *__io_file_get(struct io_submit_state *state, int fd)
 
 static bool io_bdev_nowait(struct block_device *bdev)
 {
-#ifdef CONFIG_BLOCK
 	return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
-#else
-	return true;
-#endif
 }
 
 /*
@@ -2733,14 +2729,16 @@  static bool io_file_supports_async(struct file *file, int rw)
 	umode_t mode = file_inode(file)->i_mode;
 
 	if (S_ISBLK(mode)) {
-		if (io_bdev_nowait(file->f_inode->i_bdev))
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(I_BDEV(file->f_mapping->host)))
 			return true;
 		return false;
 	}
 	if (S_ISCHR(mode) || S_ISSOCK(mode))
 		return true;
 	if (S_ISREG(mode)) {
-		if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
 		    file->f_op != &io_uring_fops)
 			return true;
 		return false;
diff --git a/fs/pipe.c b/fs/pipe.c
index 0ac197658a2d6e..c5989cfd564d45 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1342,9 +1342,8 @@  static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
 }
 
 /*
- * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
- * location, so checking ->i_pipe is not enough to verify that this is a
- * pipe.
+ * Note that i_pipe and i_cdev share the same location, so checking ->i_pipe is
+ * not enough to verify that this is a pipe.
  */
 struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice)
 {
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index f3d32b0d9008f2..6d16b2be5ac4a3 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -866,17 +866,18 @@  static bool quotactl_cmd_onoff(int cmd)
 static struct super_block *quotactl_block(const char __user *special, int cmd)
 {
 #ifdef CONFIG_BLOCK
-	struct block_device *bdev;
 	struct super_block *sb;
 	struct filename *tmp = getname(special);
 	bool excl = false, thawed = false;
+	int error;
+	dev_t dev;
 
 	if (IS_ERR(tmp))
 		return ERR_CAST(tmp);
-	bdev = lookup_bdev(tmp->name);
+	error = lookup_bdev(tmp->name, &dev);
 	putname(tmp);
-	if (IS_ERR(bdev))
-		return ERR_CAST(bdev);
+	if (error)
+		return ERR_PTR(error);
 
 	if (quotactl_cmd_onoff(cmd)) {
 		excl = true;
@@ -886,8 +887,10 @@  static struct super_block *quotactl_block(const char __user *special, int cmd)
 	}
 
 retry:
-	sb = __get_super(bdev, excl);
-	if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
+	sb = user_get_super(dev, excl);
+	if (!sb)
+		return ERR_PTR(-ENODEV);
+	if (thawed && sb->s_writers.frozen != SB_UNFROZEN) {
 		if (excl)
 			up_write(&sb->s_umount);
 		else
@@ -897,10 +900,6 @@  static struct super_block *quotactl_block(const char __user *special, int cmd)
 		put_super(sb);
 		goto retry;
 	}
-
-	bdput(bdev);
-	if (!sb)
-		return ERR_PTR(-ENODEV);
 	return sb;
 
 #else
diff --git a/fs/statfs.c b/fs/statfs.c
index 59f33752c1311f..68cb077887504f 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -235,7 +235,7 @@  SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
 
 static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
 {
-	struct super_block *s = user_get_super(dev);
+	struct super_block *s = user_get_super(dev, false);
 	int err;
 	if (!s)
 		return -EINVAL;
diff --git a/fs/super.c b/fs/super.c
index 343e5c1e538d2a..7a1611e5d0f45d 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -740,7 +740,7 @@  void iterate_supers_type(struct file_system_type *type,
 
 EXPORT_SYMBOL(iterate_supers_type);
 
-struct super_block *__get_super(struct block_device *bdev, bool excl)
+struct super_block *get_super(struct block_device *bdev)
 {
 	struct super_block *sb;
 
@@ -755,17 +755,11 @@  struct super_block *__get_super(struct block_device *bdev, bool excl)
 		if (sb->s_bdev == bdev) {
 			sb->s_count++;
 			spin_unlock(&sb_lock);
-			if (!excl)
-				down_read(&sb->s_umount);
-			else
-				down_write(&sb->s_umount);
+			down_read(&sb->s_umount);
 			/* still alive? */
 			if (sb->s_root && (sb->s_flags & SB_BORN))
 				return sb;
-			if (!excl)
-				up_read(&sb->s_umount);
-			else
-				up_write(&sb->s_umount);
+			up_read(&sb->s_umount);
 			/* nope, got unmounted */
 			spin_lock(&sb_lock);
 			__put_super(sb);
@@ -776,19 +770,6 @@  struct super_block *__get_super(struct block_device *bdev, bool excl)
 	return NULL;
 }
 
-/**
- *	get_super - get the superblock of a device
- *	@bdev: device to get the superblock for
- *
- *	Scans the superblock list and finds the superblock of the file system
- *	mounted on the device given. %NULL is returned if no match is found.
- */
-struct super_block *get_super(struct block_device *bdev)
-{
-	return __get_super(bdev, false);
-}
-EXPORT_SYMBOL(get_super);
-
 /**
  * get_active_super - get an active reference to the superblock of a device
  * @bdev: device to get the superblock for
@@ -820,7 +801,7 @@  struct super_block *get_active_super(struct block_device *bdev)
 	return NULL;
 }
 
-struct super_block *user_get_super(dev_t dev)
+struct super_block *user_get_super(dev_t dev, bool excl)
 {
 	struct super_block *sb;
 
@@ -832,11 +813,17 @@  struct super_block *user_get_super(dev_t dev)
 		if (sb->s_dev ==  dev) {
 			sb->s_count++;
 			spin_unlock(&sb_lock);
-			down_read(&sb->s_umount);
+			if (excl)
+				down_write(&sb->s_umount);
+			else
+				down_read(&sb->s_umount);
 			/* still alive? */
 			if (sb->s_root && (sb->s_flags & SB_BORN))
 				return sb;
-			up_read(&sb->s_umount);
+			if (excl)
+				up_write(&sb->s_umount);
+			else
+				up_read(&sb->s_umount);
 			/* nope, got unmounted */
 			spin_lock(&sb_lock);
 			__put_super(sb);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 12810a19edebc4..bdd7339bcda462 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1973,7 +1973,7 @@  int bdev_read_only(struct block_device *bdev);
 int set_blocksize(struct block_device *bdev, int size);
 
 const char *bdevname(struct block_device *bdev, char *buffer);
-struct block_device *lookup_bdev(const char *);
+int lookup_bdev(const char *pathname, dev_t *dev);
 
 void blkdev_show(struct seq_file *seqf, off_t offset);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a61df0dd4f1989..b0b358309657ba 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -696,7 +696,6 @@  struct inode {
 	struct list_head	i_devices;
 	union {
 		struct pipe_inode_info	*i_pipe;
-		struct block_device	*i_bdev;
 		struct cdev		*i_cdev;
 		char			*i_link;
 		unsigned		i_dir_seq;