block: move fs/block_dev.c to block/bdev.c

Move it together with the rest of the block layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210907141303.1371844-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 0 insertions, 1058 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
deleted file mode 100644
index 84c97e276047..000000000000
--- a/fs/block_dev.c
+++ /dev/null
@@ -1,1058 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *  Copyright (C) 2001  Andrea Arcangeli <andrea@suse.de> SuSE
- *  Copyright (C) 2016 - 2020 Christoph Hellwig
- */
-
-#include <linux/init.h>
-#include <linux/mm.h>
-#include <linux/slab.h>
-#include <linux/kmod.h>
-#include <linux/major.h>
-#include <linux/device_cgroup.h>
-#include <linux/blkdev.h>
-#include <linux/backing-dev.h>
-#include <linux/module.h>
-#include <linux/blkpg.h>
-#include <linux/magic.h>
-#include <linux/buffer_head.h>
-#include <linux/swap.h>
-#include <linux/writeback.h>
-#include <linux/mount.h>
-#include <linux/pseudo_fs.h>
-#include <linux/uio.h>
-#include <linux/namei.h>
-#include <linux/cleancache.h>
-#include <linux/part_stat.h>
-#include <linux/uaccess.h>
-#include "internal.h"
-#include "../block/blk.h"
-
-struct bdev_inode {
-	struct block_device bdev;
-	struct inode vfs_inode;
-};
-
-static inline struct bdev_inode *BDEV_I(struct inode *inode)
-{
-	return container_of(inode, struct bdev_inode, vfs_inode);
-}
-
-struct block_device *I_BDEV(struct inode *inode)
-{
-	return &BDEV_I(inode)->bdev;
-}
-EXPORT_SYMBOL(I_BDEV);
-
-static void bdev_write_inode(struct block_device *bdev)
-{
-	struct inode *inode = bdev->bd_inode;
-	int ret;
-
-	spin_lock(&inode->i_lock);
-	while (inode->i_state & I_DIRTY) {
-		spin_unlock(&inode->i_lock);
-		ret = write_inode_now(inode, true);
-		if (ret) {
-			char name[BDEVNAME_SIZE];
-			pr_warn_ratelimited("VFS: Dirty inode writeback failed "
-					    "for block device %s (err=%d).\n",
-					    bdevname(bdev, name), ret);
-		}
-		spin_lock(&inode->i_lock);
-	}
-	spin_unlock(&inode->i_lock);
-}
-
-/* Kill _all_ buffers and pagecache , dirty or not.. */
-static void kill_bdev(struct block_device *bdev)
-{
-	struct address_space *mapping = bdev->bd_inode->i_mapping;
-
-	if (mapping_empty(mapping))
-		return;
-
-	invalidate_bh_lrus();
-	truncate_inode_pages(mapping, 0);
-}
-
-/* Invalidate clean unused buffers and pagecache. */
-void invalidate_bdev(struct block_device *bdev)
-{
-	struct address_space *mapping = bdev->bd_inode->i_mapping;
-
-	if (mapping->nrpages) {
-		invalidate_bh_lrus();
-		lru_add_drain_all();	/* make sure all lru add caches are flushed */
-		invalidate_mapping_pages(mapping, 0, -1);
-	}
-	/* 99% of the time, we don't need to flush the cleancache on the bdev.
-	 * But, for the strange corners, lets be cautious
-	 */
-	cleancache_invalidate_inode(mapping);
-}
-EXPORT_SYMBOL(invalidate_bdev);
-
-/*
- * Drop all buffers & page cache for given bdev range. This function bails
- * with error if bdev has other exclusive owner (such as filesystem).
- */
-int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
-			loff_t lstart, loff_t lend)
-{
-	/*
-	 * If we don't hold exclusive handle for the device, upgrade to it
-	 * while we discard the buffer cache to avoid discarding buffers
-	 * under live filesystem.
-	 */
-	if (!(mode & FMODE_EXCL)) {
-		int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
-		if (err)
-			goto invalidate;
-	}
-
-	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
-	if (!(mode & FMODE_EXCL))
-		bd_abort_claiming(bdev, truncate_bdev_range);
-	return 0;
-
-invalidate:
-	/*
-	 * Someone else has handle exclusively open. Try invalidating instead.
-	 * The 'end' argument is inclusive so the rounding is safe.
-	 */
-	return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
-					     lstart >> PAGE_SHIFT,
-					     lend >> PAGE_SHIFT);
-}
-
-static void set_init_blocksize(struct block_device *bdev)
-{
-	unsigned int bsize = bdev_logical_block_size(bdev);
-	loff_t size = i_size_read(bdev->bd_inode);
-
-	while (bsize < PAGE_SIZE) {
-		if (size & bsize)
-			break;
-		bsize <<= 1;
-	}
-	bdev->bd_inode->i_blkbits = blksize_bits(bsize);
-}
-
-int set_blocksize(struct block_device *bdev, int size)
-{
-	/* Size must be a power of two, and between 512 and PAGE_SIZE */
-	if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
-		return -EINVAL;
-
-	/* Size cannot be smaller than the size supported by the device */
-	if (size < bdev_logical_block_size(bdev))
-		return -EINVAL;
-
-	/* Don't change the size if it is same as current */
-	if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
-		sync_blockdev(bdev);
-		bdev->bd_inode->i_blkbits = blksize_bits(size);
-		kill_bdev(bdev);
-	}
-	return 0;
-}
-
-EXPORT_SYMBOL(set_blocksize);
-
-int sb_set_blocksize(struct super_block *sb, int size)
-{
-	if (set_blocksize(sb->s_bdev, size))
-		return 0;
-	/* If we get here, we know size is power of two
-	 * and it's value is between 512 and PAGE_SIZE */
-	sb->s_blocksize = size;
-	sb->s_blocksize_bits = blksize_bits(size);
-	return sb->s_blocksize;
-}
-
-EXPORT_SYMBOL(sb_set_blocksize);
-
-int sb_min_blocksize(struct super_block *sb, int size)
-{
-	int minsize = bdev_logical_block_size(sb->s_bdev);
-	if (size < minsize)
-		size = minsize;
-	return sb_set_blocksize(sb, size);
-}
-
-EXPORT_SYMBOL(sb_min_blocksize);
-
-int __sync_blockdev(struct block_device *bdev, int wait)
-{
-	if (!bdev)
-		return 0;
-	if (!wait)
-		return filemap_flush(bdev->bd_inode->i_mapping);
-	return filemap_write_and_wait(bdev->bd_inode->i_mapping);
-}
-
-/*
- * Write out and wait upon all the dirty data associated with a block
- * device via its mapping.  Does not take the superblock lock.
- */
-int sync_blockdev(struct block_device *bdev)
-{
-	return __sync_blockdev(bdev, 1);
-}
-EXPORT_SYMBOL(sync_blockdev);
-
-/*
- * Write out and wait upon all dirty data associated with this
- * device.   Filesystem data as well as the underlying block
- * device.  Takes the superblock lock.
- */
-int fsync_bdev(struct block_device *bdev)
-{
-	struct super_block *sb = get_super(bdev);
-	if (sb) {
-		int res = sync_filesystem(sb);
-		drop_super(sb);
-		return res;
-	}
-	return sync_blockdev(bdev);
-}
-EXPORT_SYMBOL(fsync_bdev);
-
-/**
- * freeze_bdev  --  lock a filesystem and force it into a consistent state
- * @bdev:	blockdevice to lock
- *
- * If a superblock is found on this device, we take the s_umount semaphore
- * on it to make sure nobody unmounts until the snapshot creation is done.
- * The reference counter (bd_fsfreeze_count) guarantees that only the last
- * unfreeze process can unfreeze the frozen filesystem actually when multiple
- * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
- * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
- * actually.
- */
-int freeze_bdev(struct block_device *bdev)
-{
-	struct super_block *sb;
-	int error = 0;
-
-	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (++bdev->bd_fsfreeze_count > 1)
-		goto done;
-
-	sb = get_active_super(bdev);
-	if (!sb)
-		goto sync;
-	if (sb->s_op->freeze_super)
-		error = sb->s_op->freeze_super(sb);
-	else
-		error = freeze_super(sb);
-	deactivate_super(sb);
-
-	if (error) {
-		bdev->bd_fsfreeze_count--;
-		goto done;
-	}
-	bdev->bd_fsfreeze_sb = sb;
-
-sync:
-	sync_blockdev(bdev);
-done:
-	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	return error;
-}
-EXPORT_SYMBOL(freeze_bdev);
-
-/**
- * thaw_bdev  -- unlock filesystem
- * @bdev:	blockdevice to unlock
- *
- * Unlocks the filesystem and marks it writeable again after freeze_bdev().
- */
-int thaw_bdev(struct block_device *bdev)
-{
-	struct super_block *sb;
-	int error = -EINVAL;
-
-	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (!bdev->bd_fsfreeze_count)
-		goto out;
-
-	error = 0;
-	if (--bdev->bd_fsfreeze_count > 0)
-		goto out;
-
-	sb = bdev->bd_fsfreeze_sb;
-	if (!sb)
-		goto out;
-
-	if (sb->s_op->thaw_super)
-		error = sb->s_op->thaw_super(sb);
-	else
-		error = thaw_super(sb);
-	if (error)
-		bdev->bd_fsfreeze_count++;
-	else
-		bdev->bd_fsfreeze_sb = NULL;
-out:
-	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	return error;
-}
-EXPORT_SYMBOL(thaw_bdev);
-
-/**
- * bdev_read_page() - Start reading a page from a block device
- * @bdev: The device to read the page from
- * @sector: The offset on the device to read the page to (need not be aligned)
- * @page: The page to read
- *
- * On entry, the page should be locked.  It will be unlocked when the page
- * has been read.  If the block driver implements rw_page synchronously,
- * that will be true on exit from this function, but it need not be.
- *
- * Errors returned by this function are usually "soft", eg out of memory, or
- * queue full; callers should try a different route to read this page rather
- * than propagate an error back up the stack.
- *
- * Return: negative errno if an error occurs, 0 if submission was successful.
- */
-int bdev_read_page(struct block_device *bdev, sector_t sector,
-			struct page *page)
-{
-	const struct block_device_operations *ops = bdev->bd_disk->fops;
-	int result = -EOPNOTSUPP;
-
-	if (!ops->rw_page || bdev_get_integrity(bdev))
-		return result;
-
-	result = blk_queue_enter(bdev->bd_disk->queue, 0);
-	if (result)
-		return result;
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_READ);
-	blk_queue_exit(bdev->bd_disk->queue);
-	return result;
-}
-
-/**
- * bdev_write_page() - Start writing a page to a block device
- * @bdev: The device to write the page to
- * @sector: The offset on the device to write the page to (need not be aligned)
- * @page: The page to write
- * @wbc: The writeback_control for the write
- *
- * On entry, the page should be locked and not currently under writeback.
- * On exit, if the write started successfully, the page will be unlocked and
- * under writeback.  If the write failed already (eg the driver failed to
- * queue the page to the device), the page will still be locked.  If the
- * caller is a ->writepage implementation, it will need to unlock the page.
- *
- * Errors returned by this function are usually "soft", eg out of memory, or
- * queue full; callers should try a different route to write this page rather
- * than propagate an error back up the stack.
- *
- * Return: negative errno if an error occurs, 0 if submission was successful.
- */
-int bdev_write_page(struct block_device *bdev, sector_t sector,
-			struct page *page, struct writeback_control *wbc)
-{
-	int result;
-	const struct block_device_operations *ops = bdev->bd_disk->fops;
-
-	if (!ops->rw_page || bdev_get_integrity(bdev))
-		return -EOPNOTSUPP;
-	result = blk_queue_enter(bdev->bd_disk->queue, 0);
-	if (result)
-		return result;
-
-	set_page_writeback(page);
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_WRITE);
-	if (result) {
-		end_page_writeback(page);
-	} else {
-		clean_page_buffers(page);
-		unlock_page(page);
-	}
-	blk_queue_exit(bdev->bd_disk->queue);
-	return result;
-}
-
-/*
- * pseudo-fs
- */
-
-static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
-static struct kmem_cache * bdev_cachep __read_mostly;
-
-static struct inode *bdev_alloc_inode(struct super_block *sb)
-{
-	struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
-
-	if (!ei)
-		return NULL;
-	memset(&ei->bdev, 0, sizeof(ei->bdev));
-	return &ei->vfs_inode;
-}
-
-static void bdev_free_inode(struct inode *inode)
-{
-	struct block_device *bdev = I_BDEV(inode);
-
-	free_percpu(bdev->bd_stats);
-	kfree(bdev->bd_meta_info);
-
-	if (!bdev_is_partition(bdev)) {
-		if (bdev->bd_disk && bdev->bd_disk->bdi)
-			bdi_put(bdev->bd_disk->bdi);
-		kfree(bdev->bd_disk);
-	}
-
-	if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
-		blk_free_ext_minor(MINOR(bdev->bd_dev));
-
-	kmem_cache_free(bdev_cachep, BDEV_I(inode));
-}
-
-static void init_once(void *data)
-{
-	struct bdev_inode *ei = data;
-
-	inode_init_once(&ei->vfs_inode);
-}
-
-static void bdev_evict_inode(struct inode *inode)
-{
-	truncate_inode_pages_final(&inode->i_data);
-	invalidate_inode_buffers(inode); /* is it needed here? */
-	clear_inode(inode);
-}
-
-static const struct super_operations bdev_sops = {
-	.statfs = simple_statfs,
-	.alloc_inode = bdev_alloc_inode,
-	.free_inode = bdev_free_inode,
-	.drop_inode = generic_delete_inode,
-	.evict_inode = bdev_evict_inode,
-};
-
-static int bd_init_fs_context(struct fs_context *fc)
-{
-	struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
-	if (!ctx)
-		return -ENOMEM;
-	fc->s_iflags |= SB_I_CGROUPWB;
-	ctx->ops = &bdev_sops;
-	return 0;
-}
-
-static struct file_system_type bd_type = {
-	.name		= "bdev",
-	.init_fs_context = bd_init_fs_context,
-	.kill_sb	= kill_anon_super,
-};
-
-struct super_block *blockdev_superblock __read_mostly;
-EXPORT_SYMBOL_GPL(blockdev_superblock);
-
-void __init bdev_cache_init(void)
-{
-	int err;
-	static struct vfsmount *bd_mnt;
-
-	bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
-			0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
-				SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC),
-			init_once);
-	err = register_filesystem(&bd_type);
-	if (err)
-		panic("Cannot register bdev pseudo-fs");
-	bd_mnt = kern_mount(&bd_type);
-	if (IS_ERR(bd_mnt))
-		panic("Cannot create bdev pseudo-fs");
-	blockdev_superblock = bd_mnt->mnt_sb;   /* For writeback */
-}
-
-struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
-{
-	struct block_device *bdev;
-	struct inode *inode;
-
-	inode = new_inode(blockdev_superblock);
-	if (!inode)
-		return NULL;
-	inode->i_mode = S_IFBLK;
-	inode->i_rdev = 0;
-	inode->i_data.a_ops = &def_blk_aops;
-	mapping_set_gfp_mask(&inode->i_data, GFP_USER);
-
-	bdev = I_BDEV(inode);
-	mutex_init(&bdev->bd_fsfreeze_mutex);
-	spin_lock_init(&bdev->bd_size_lock);
-	bdev->bd_disk = disk;
-	bdev->bd_partno = partno;
-	bdev->bd_inode = inode;
-	bdev->bd_stats = alloc_percpu(struct disk_stats);
-	if (!bdev->bd_stats) {
-		iput(inode);
-		return NULL;
-	}
-	return bdev;
-}
-
-void bdev_add(struct block_device *bdev, dev_t dev)
-{
-	bdev->bd_dev = dev;
-	bdev->bd_inode->i_rdev = dev;
-	bdev->bd_inode->i_ino = dev;
-	insert_inode_hash(bdev->bd_inode);
-}
-
-long nr_blockdev_pages(void)
-{
-	struct inode *inode;
-	long ret = 0;
-
-	spin_lock(&blockdev_superblock->s_inode_list_lock);
-	list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
-		ret += inode->i_mapping->nrpages;
-	spin_unlock(&blockdev_superblock->s_inode_list_lock);
-
-	return ret;
-}
-
-/**
- * bd_may_claim - test whether a block device can be claimed
- * @bdev: block device of interest
- * @whole: whole block device containing @bdev, may equal @bdev
- * @holder: holder trying to claim @bdev
- *
- * Test whether @bdev can be claimed by @holder.
- *
- * CONTEXT:
- * spin_lock(&bdev_lock).
- *
- * RETURNS:
- * %true if @bdev can be claimed, %false otherwise.
- */
-static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
-			 void *holder)
-{
-	if (bdev->bd_holder == holder)
-		return true;	 /* already a holder */
-	else if (bdev->bd_holder != NULL)
-		return false; 	 /* held by someone else */
-	else if (whole == bdev)
-		return true;  	 /* is a whole device which isn't held */
-
-	else if (whole->bd_holder == bd_may_claim)
-		return true; 	 /* is a partition of a device that is being partitioned */
-	else if (whole->bd_holder != NULL)
-		return false;	 /* is a partition of a held device */
-	else
-		return true;	 /* is a partition of an un-held device */
-}
-
-/**
- * bd_prepare_to_claim - claim a block device
- * @bdev: block device of interest
- * @holder: holder trying to claim @bdev
- *
- * Claim @bdev.  This function fails if @bdev is already claimed by another
- * holder and waits if another claiming is in progress. return, the caller
- * has ownership of bd_claiming and bd_holder[s].
- *
- * RETURNS:
- * 0 if @bdev can be claimed, -EBUSY otherwise.
- */
-int bd_prepare_to_claim(struct block_device *bdev, void *holder)
-{
-	struct block_device *whole = bdev_whole(bdev);
-
-	if (WARN_ON_ONCE(!holder))
-		return -EINVAL;
-retry:
-	spin_lock(&bdev_lock);
-	/* if someone else claimed, fail */
-	if (!bd_may_claim(bdev, whole, holder)) {
-		spin_unlock(&bdev_lock);
-		return -EBUSY;
-	}
-
-	/* if claiming is already in progress, wait for it to finish */
-	if (whole->bd_claiming) {
-		wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
-		DEFINE_WAIT(wait);
-
-		prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
-		spin_unlock(&bdev_lock);
-		schedule();
-		finish_wait(wq, &wait);
-		goto retry;
-	}
-
-	/* yay, all mine */
-	whole->bd_claiming = holder;
-	spin_unlock(&bdev_lock);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
-
-static void bd_clear_claiming(struct block_device *whole, void *holder)
-{
-	lockdep_assert_held(&bdev_lock);
-	/* tell others that we're done */
-	BUG_ON(whole->bd_claiming != holder);
-	whole->bd_claiming = NULL;
-	wake_up_bit(&whole->bd_claiming, 0);
-}
-
-/**
- * bd_finish_claiming - finish claiming of a block device
- * @bdev: block device of interest
- * @holder: holder that has claimed @bdev
- *
- * Finish exclusive open of a block device. Mark the device as exlusively
- * open by the holder and wake up all waiters for exclusive open to finish.
- */
-static void bd_finish_claiming(struct block_device *bdev, void *holder)
-{
-	struct block_device *whole = bdev_whole(bdev);
-
-	spin_lock(&bdev_lock);
-	BUG_ON(!bd_may_claim(bdev, whole, holder));
-	/*
-	 * Note that for a whole device bd_holders will be incremented twice,
-	 * and bd_holder will be set to bd_may_claim before being set to holder
-	 */
-	whole->bd_holders++;
-	whole->bd_holder = bd_may_claim;
-	bdev->bd_holders++;
-	bdev->bd_holder = holder;
-	bd_clear_claiming(whole, holder);
-	spin_unlock(&bdev_lock);
-}
-
-/**
- * bd_abort_claiming - abort claiming of a block device
- * @bdev: block device of interest
- * @holder: holder that has claimed @bdev
- *
- * Abort claiming of a block device when the exclusive open failed. This can be
- * also used when exclusive open is not actually desired and we just needed
- * to block other exclusive openers for a while.
- */
-void bd_abort_claiming(struct block_device *bdev, void *holder)
-{
-	spin_lock(&bdev_lock);
-	bd_clear_claiming(bdev_whole(bdev), holder);
-	spin_unlock(&bdev_lock);
-}
-EXPORT_SYMBOL(bd_abort_claiming);
-
-static void blkdev_flush_mapping(struct block_device *bdev)
-{
-	WARN_ON_ONCE(bdev->bd_holders);
-	sync_blockdev(bdev);
-	kill_bdev(bdev);
-	bdev_write_inode(bdev);
-}
-
-static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
-{
-	struct gendisk *disk = bdev->bd_disk;
-	int ret = 0;
-
-	if (disk->fops->open) {
-		ret = disk->fops->open(bdev, mode);
-		if (ret) {
-			/* avoid ghost partitions on a removed medium */
-			if (ret == -ENOMEDIUM &&
-			     test_bit(GD_NEED_PART_SCAN, &disk->state))
-				bdev_disk_changed(disk, true);
-			return ret;
-		}
-	}
-
-	if (!bdev->bd_openers)
-		set_init_blocksize(bdev);
-	if (test_bit(GD_NEED_PART_SCAN, &disk->state))
-		bdev_disk_changed(disk, false);
-	bdev->bd_openers++;
-	return 0;;
-}
-
-static void blkdev_put_whole(struct block_device *bdev, fmode_t mode)
-{
-	if (!--bdev->bd_openers)
-		blkdev_flush_mapping(bdev);
-	if (bdev->bd_disk->fops->release)
-		bdev->bd_disk->fops->release(bdev->bd_disk, mode);
-}
-
-static int blkdev_get_part(struct block_device *part, fmode_t mode)
-{
-	struct gendisk *disk = part->bd_disk;
-	int ret;
-
-	if (part->bd_openers)
-		goto done;
-
-	ret = blkdev_get_whole(bdev_whole(part), mode);
-	if (ret)
-		return ret;
-
-	ret = -ENXIO;
-	if (!bdev_nr_sectors(part))
-		goto out_blkdev_put;
-
-	disk->open_partitions++;
-	set_init_blocksize(part);
-done:
-	part->bd_openers++;
-	return 0;
-
-out_blkdev_put:
-	blkdev_put_whole(bdev_whole(part), mode);
-	return ret;
-}
-
-static void blkdev_put_part(struct block_device *part, fmode_t mode)
-{
-	struct block_device *whole = bdev_whole(part);
-
-	if (--part->bd_openers)
-		return;
-	blkdev_flush_mapping(part);
-	whole->bd_disk->open_partitions--;
-	blkdev_put_whole(whole, mode);
-}
-
-struct block_device *blkdev_get_no_open(dev_t dev)
-{
-	struct block_device *bdev;
-	struct inode *inode;
-
-	inode = ilookup(blockdev_superblock, dev);
-	if (!inode) {
-		blk_request_module(dev);
-		inode = ilookup(blockdev_superblock, dev);
-		if (!inode)
-			return NULL;
-	}
-
-	/* switch from the inode reference to a device mode one: */
-	bdev = &BDEV_I(inode)->bdev;
-	if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
-		bdev = NULL;
-	iput(inode);
-
-	if (!bdev)
-		return NULL;
-	if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) ||
-	    !try_module_get(bdev->bd_disk->fops->owner)) {
-		put_device(&bdev->bd_device);
-		return NULL;
-	}
-
-	return bdev;
-}
-
-void blkdev_put_no_open(struct block_device *bdev)
-{
-	module_put(bdev->bd_disk->fops->owner);
-	put_device(&bdev->bd_device);
-}
-
-/**
- * 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 block device described by device number @dev. 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.
- *
- * 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:
- * Reference to the block_device on success, ERR_PTR(-errno) on failure.
- */
-struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
-{
-	bool unblock_events = true;
-	struct block_device *bdev;
-	struct gendisk *disk;
-	int ret;
-
-	ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
-			MAJOR(dev), MINOR(dev),
-			((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
-			((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
-	if (ret)
-		return ERR_PTR(ret);
-
-	bdev = blkdev_get_no_open(dev);
-	if (!bdev)
-		return ERR_PTR(-ENXIO);
-	disk = bdev->bd_disk;
-
-	if (mode & FMODE_EXCL) {
-		ret = bd_prepare_to_claim(bdev, holder);
-		if (ret)
-			goto put_blkdev;
-	}
-
-	disk_block_events(disk);
-
-	mutex_lock(&disk->open_mutex);
-	ret = -ENXIO;
-	if (!disk_live(disk))
-		goto abort_claiming;
-	if (bdev_is_partition(bdev))
-		ret = blkdev_get_part(bdev, mode);
-	else
-		ret = blkdev_get_whole(bdev, mode);
-	if (ret)
-		goto abort_claiming;
-	if (mode & FMODE_EXCL) {
-		bd_finish_claiming(bdev, holder);
-
-		/*
-		 * Block event polling for write claims if requested.  Any write
-		 * holder makes the write_holder state stick until all are
-		 * released.  This is good enough and tracking individual
-		 * writeable reference is too fragile given the way @mode is
-		 * used in blkdev_get/put().
-		 */
-		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
-		    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
-			bdev->bd_write_holder = true;
-			unblock_events = false;
-		}
-	}
-	mutex_unlock(&disk->open_mutex);
-
-	if (unblock_events)
-		disk_unblock_events(disk);
-	return bdev;
-
-abort_claiming:
-	if (mode & FMODE_EXCL)
-		bd_abort_claiming(bdev, holder);
-	mutex_unlock(&disk->open_mutex);
-	disk_unblock_events(disk);
-put_blkdev:
-	blkdev_put_no_open(bdev);
-	return ERR_PTR(ret);
-}
-EXPORT_SYMBOL(blkdev_get_by_dev);
-
-/**
- * blkdev_get_by_path - open a block device by name
- * @path: path to the block device to open
- * @mode: FMODE_* mask
- * @holder: exclusive holder identifier
- *
- * Open the block device described by the device file at @path.  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:
- * 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;
-	dev_t dev;
-	int error;
-
-	error = lookup_bdev(path, &dev);
-	if (error)
-		return ERR_PTR(error);
-
-	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);
-	}
-
-	return bdev;
-}
-EXPORT_SYMBOL(blkdev_get_by_path);
-
-void blkdev_put(struct block_device *bdev, fmode_t mode)
-{
-	struct gendisk *disk = bdev->bd_disk;
-
-	/*
-	 * Sync early if it looks like we're the last one.  If someone else
-	 * opens the block device between now and the decrement of bd_openers
-	 * then we did a sync that we didn't need to, but that's not the end
-	 * of the world and we want to avoid long (could be several minute)
-	 * syncs while holding the mutex.
-	 */
-	if (bdev->bd_openers == 1)
-		sync_blockdev(bdev);
-
-	mutex_lock(&disk->open_mutex);
-	if (mode & FMODE_EXCL) {
-		struct block_device *whole = bdev_whole(bdev);
-		bool bdev_free;
-
-		/*
-		 * Release a claim on the device.  The holder fields
-		 * are protected with bdev_lock.  open_mutex is to
-		 * synchronize disk_holder unlinking.
-		 */
-		spin_lock(&bdev_lock);
-
-		WARN_ON_ONCE(--bdev->bd_holders < 0);
-		WARN_ON_ONCE(--whole->bd_holders < 0);
-
-		if ((bdev_free = !bdev->bd_holders))
-			bdev->bd_holder = NULL;
-		if (!whole->bd_holders)
-			whole->bd_holder = NULL;
-
-		spin_unlock(&bdev_lock);
-
-		/*
-		 * If this was the last claim, remove holder link and
-		 * unblock evpoll if it was a write holder.
-		 */
-		if (bdev_free && bdev->bd_write_holder) {
-			disk_unblock_events(disk);
-			bdev->bd_write_holder = false;
-		}
-	}
-
-	/*
-	 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
-	 * event.  This is to ensure detection of media removal commanded
-	 * from userland - e.g. eject(1).
-	 */
-	disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
-
-	if (bdev_is_partition(bdev))
-		blkdev_put_part(bdev, mode);
-	else
-		blkdev_put_whole(bdev, mode);
-	mutex_unlock(&disk->open_mutex);
-
-	blkdev_put_no_open(bdev);
-}
-EXPORT_SYMBOL(blkdev_put);
-
-/**
- * lookup_bdev  - lookup a struct block_device by name
- * @pathname:	special file representing the block device
- * @dev:	return value of the block device's dev_t
- *
- * Get a reference to the blockdevice at @pathname in the current
- * namespace if possible and return it.  Return ERR_PTR(error)
- * otherwise.
- */
-int lookup_bdev(const char *pathname, dev_t *dev)
-{
-	struct inode *inode;
-	struct path path;
-	int error;
-
-	if (!pathname || !*pathname)
-		return -EINVAL;
-
-	error = kern_path(pathname, LOOKUP_FOLLOW, &path);
-	if (error)
-		return error;
-
-	inode = d_backing_inode(path.dentry);
-	error = -ENOTBLK;
-	if (!S_ISBLK(inode->i_mode))
-		goto out_path_put;
-	error = -EACCES;
-	if (!may_open_dev(&path))
-		goto out_path_put;
-
-	*dev = inode->i_rdev;
-	error = 0;
-out_path_put:
-	path_put(&path);
-	return error;
-}
-EXPORT_SYMBOL(lookup_bdev);
-
-int __invalidate_device(struct block_device *bdev, bool kill_dirty)
-{
-	struct super_block *sb = get_super(bdev);
-	int res = 0;
-
-	if (sb) {
-		/*
-		 * no need to lock the super, get_super holds the
-		 * read mutex so the filesystem cannot go away
-		 * under us (->put_super runs with the write lock
-		 * hold).
-		 */
-		shrink_dcache_sb(sb);
-		res = invalidate_inodes(sb, kill_dirty);
-		drop_super(sb);
-	}
-	invalidate_bdev(bdev);
-	return res;
-}
-EXPORT_SYMBOL(__invalidate_device);
-
-void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
-{
-	struct inode *inode, *old_inode = NULL;
-
-	spin_lock(&blockdev_superblock->s_inode_list_lock);
-	list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
-		struct address_space *mapping = inode->i_mapping;
-		struct block_device *bdev;
-
-		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
-		    mapping->nrpages == 0) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
-		__iget(inode);
-		spin_unlock(&inode->i_lock);
-		spin_unlock(&blockdev_superblock->s_inode_list_lock);
-		/*
-		 * We hold a reference to 'inode' so it couldn't have been
-		 * removed from s_inodes list while we dropped the
-		 * s_inode_list_lock  We cannot iput the inode now as we can
-		 * be holding the last reference and we cannot iput it under
-		 * s_inode_list_lock. So we keep the reference and iput it
-		 * later.
-		 */
-		iput(old_inode);
-		old_inode = inode;
-		bdev = I_BDEV(inode);
-
-		mutex_lock(&bdev->bd_disk->open_mutex);
-		if (bdev->bd_openers)
-			func(bdev, arg);
-		mutex_unlock(&bdev->bd_disk->open_mutex);
-
-		spin_lock(&blockdev_superblock->s_inode_list_lock);
-	}
-	spin_unlock(&blockdev_superblock->s_inode_list_lock);
-	iput(old_inode);
-}