Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 923 insertions, 0 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
new file mode 100644
index 000000000000..d19d07c49ad3
--- /dev/null
+++ b/fs/block_dev.c
@@ -0,0 +1,923 @@
+/*
+ *  linux/fs/block_dev.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *  Copyright (C) 2001  Andrea Arcangeli <andrea@suse.de> SuSE
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/major.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/smp_lock.h>
+#include <linux/highmem.h>
+#include <linux/blkdev.h>
+#include <linux/module.h>
+#include <linux/blkpg.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/mount.h>
+#include <linux/uio.h>
+#include <linux/namei.h>
+#include <asm/uaccess.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);
+}
+
+inline struct block_device *I_BDEV(struct inode *inode)
+{
+	return &BDEV_I(inode)->bdev;
+}
+
+EXPORT_SYMBOL(I_BDEV);
+
+static sector_t max_block(struct block_device *bdev)
+{
+	sector_t retval = ~((sector_t)0);
+	loff_t sz = i_size_read(bdev->bd_inode);
+
+	if (sz) {
+		unsigned int size = block_size(bdev);
+		unsigned int sizebits = blksize_bits(size);
+		retval = (sz >> sizebits);
+	}
+	return retval;
+}
+
+/* Kill _all_ buffers, dirty or not.. */
+static void kill_bdev(struct block_device *bdev)
+{
+	invalidate_bdev(bdev, 1);
+	truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
+}	
+
+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 || (size & (size-1)))
+		return -EINVAL;
+
+	/* Size cannot be smaller than the size supported by the device */
+	if (size < bdev_hardsect_size(bdev))
+		return -EINVAL;
+
+	/* Don't change the size if it is same as current */
+	if (bdev->bd_block_size != size) {
+		sync_blockdev(bdev);
+		bdev->bd_block_size = size;
+		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)
+{
+	int bits = 9; /* 2^9 = 512 */
+
+	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;
+	for (size >>= 10; size; size >>= 1)
+		++bits;
+	sb->s_blocksize_bits = bits;
+	return sb->s_blocksize;
+}
+
+EXPORT_SYMBOL(sb_set_blocksize);
+
+int sb_min_blocksize(struct super_block *sb, int size)
+{
+	int minsize = bdev_hardsect_size(sb->s_bdev);
+	if (size < minsize)
+		size = minsize;
+	return sb_set_blocksize(sb, size);
+}
+
+EXPORT_SYMBOL(sb_min_blocksize);
+
+static int
+blkdev_get_block(struct inode *inode, sector_t iblock,
+		struct buffer_head *bh, int create)
+{
+	if (iblock >= max_block(I_BDEV(inode))) {
+		if (create)
+			return -EIO;
+
+		/*
+		 * for reads, we're just trying to fill a partial page.
+		 * return a hole, they will have to call get_block again
+		 * before they can fill it, and they will get -EIO at that
+		 * time
+		 */
+		return 0;
+	}
+	bh->b_bdev = I_BDEV(inode);
+	bh->b_blocknr = iblock;
+	set_buffer_mapped(bh);
+	return 0;
+}
+
+static int
+blkdev_get_blocks(struct inode *inode, sector_t iblock,
+		unsigned long max_blocks, struct buffer_head *bh, int create)
+{
+	sector_t end_block = max_block(I_BDEV(inode));
+
+	if ((iblock + max_blocks) > end_block) {
+		max_blocks = end_block - iblock;
+		if ((long)max_blocks <= 0) {
+			if (create)
+				return -EIO;	/* write fully beyond EOF */
+			/*
+			 * It is a read which is fully beyond EOF.  We return
+			 * a !buffer_mapped buffer
+			 */
+			max_blocks = 0;
+		}
+	}
+
+	bh->b_bdev = I_BDEV(inode);
+	bh->b_blocknr = iblock;
+	bh->b_size = max_blocks << inode->i_blkbits;
+	if (max_blocks)
+		set_buffer_mapped(bh);
+	return 0;
+}
+
+static ssize_t
+blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
+			loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+
+	return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
+				iov, offset, nr_segs, blkdev_get_blocks, NULL);
+}
+
+static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
+{
+	return block_write_full_page(page, blkdev_get_block, wbc);
+}
+
+static int blkdev_readpage(struct file * file, struct page * page)
+{
+	return block_read_full_page(page, blkdev_get_block);
+}
+
+static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
+{
+	return block_prepare_write(page, from, to, blkdev_get_block);
+}
+
+static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to)
+{
+	return block_commit_write(page, from, to);
+}
+
+/*
+ * private llseek:
+ * for a block special file file->f_dentry->d_inode->i_size is zero
+ * so we compute the size by hand (just as in block_read/write above)
+ */
+static loff_t block_llseek(struct file *file, loff_t offset, int origin)
+{
+	struct inode *bd_inode = file->f_mapping->host;
+	loff_t size;
+	loff_t retval;
+
+	down(&bd_inode->i_sem);
+	size = i_size_read(bd_inode);
+
+	switch (origin) {
+		case 2:
+			offset += size;
+			break;
+		case 1:
+			offset += file->f_pos;
+	}
+	retval = -EINVAL;
+	if (offset >= 0 && offset <= size) {
+		if (offset != file->f_pos) {
+			file->f_pos = offset;
+		}
+		retval = offset;
+	}
+	up(&bd_inode->i_sem);
+	return retval;
+}
+	
+/*
+ *	Filp is never NULL; the only case when ->fsync() is called with
+ *	NULL first argument is nfsd_sync_dir() and that's not a directory.
+ */
+ 
+static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
+{
+	return sync_blockdev(I_BDEV(filp->f_mapping->host));
+}
+
+/*
+ * pseudo-fs
+ */
+
+static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
+static kmem_cache_t * bdev_cachep;
+
+static struct inode *bdev_alloc_inode(struct super_block *sb)
+{
+	struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL);
+	if (!ei)
+		return NULL;
+	return &ei->vfs_inode;
+}
+
+static void bdev_destroy_inode(struct inode *inode)
+{
+	struct bdev_inode *bdi = BDEV_I(inode);
+
+	bdi->bdev.bd_inode_backing_dev_info = NULL;
+	kmem_cache_free(bdev_cachep, bdi);
+}
+
+static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
+{
+	struct bdev_inode *ei = (struct bdev_inode *) foo;
+	struct block_device *bdev = &ei->bdev;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR)
+	{
+		memset(bdev, 0, sizeof(*bdev));
+		sema_init(&bdev->bd_sem, 1);
+		sema_init(&bdev->bd_mount_sem, 1);
+		INIT_LIST_HEAD(&bdev->bd_inodes);
+		INIT_LIST_HEAD(&bdev->bd_list);
+		inode_init_once(&ei->vfs_inode);
+	}
+}
+
+static inline void __bd_forget(struct inode *inode)
+{
+	list_del_init(&inode->i_devices);
+	inode->i_bdev = NULL;
+	inode->i_mapping = &inode->i_data;
+}
+
+static void bdev_clear_inode(struct inode *inode)
+{
+	struct block_device *bdev = &BDEV_I(inode)->bdev;
+	struct list_head *p;
+	spin_lock(&bdev_lock);
+	while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
+		__bd_forget(list_entry(p, struct inode, i_devices));
+	}
+	list_del_init(&bdev->bd_list);
+	spin_unlock(&bdev_lock);
+}
+
+static struct super_operations bdev_sops = {
+	.statfs = simple_statfs,
+	.alloc_inode = bdev_alloc_inode,
+	.destroy_inode = bdev_destroy_inode,
+	.drop_inode = generic_delete_inode,
+	.clear_inode = bdev_clear_inode,
+};
+
+static struct super_block *bd_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576);
+}
+
+static struct file_system_type bd_type = {
+	.name		= "bdev",
+	.get_sb		= bd_get_sb,
+	.kill_sb	= kill_anon_super,
+};
+
+static struct vfsmount *bd_mnt;
+struct super_block *blockdev_superblock;
+
+void __init bdev_cache_init(void)
+{
+	int err;
+	bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
+			0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
+			init_once, NULL);
+	err = register_filesystem(&bd_type);
+	if (err)
+		panic("Cannot register bdev pseudo-fs");
+	bd_mnt = kern_mount(&bd_type);
+	err = PTR_ERR(bd_mnt);
+	if (IS_ERR(bd_mnt))
+		panic("Cannot create bdev pseudo-fs");
+	blockdev_superblock = bd_mnt->mnt_sb;	/* For writeback */
+}
+
+/*
+ * Most likely _very_ bad one - but then it's hardly critical for small
+ * /dev and can be fixed when somebody will need really large one.
+ * Keep in mind that it will be fed through icache hash function too.
+ */
+static inline unsigned long hash(dev_t dev)
+{
+	return MAJOR(dev)+MINOR(dev);
+}
+
+static int bdev_test(struct inode *inode, void *data)
+{
+	return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
+}
+
+static int bdev_set(struct inode *inode, void *data)
+{
+	BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
+	return 0;
+}
+
+static LIST_HEAD(all_bdevs);
+
+struct block_device *bdget(dev_t dev)
+{
+	struct block_device *bdev;
+	struct inode *inode;
+
+	inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
+			bdev_test, bdev_set, &dev);
+
+	if (!inode)
+		return NULL;
+
+	bdev = &BDEV_I(inode)->bdev;
+
+	if (inode->i_state & I_NEW) {
+		bdev->bd_contains = NULL;
+		bdev->bd_inode = inode;
+		bdev->bd_block_size = (1 << inode->i_blkbits);
+		bdev->bd_part_count = 0;
+		bdev->bd_invalidated = 0;
+		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);
+		inode->i_data.backing_dev_info = &default_backing_dev_info;
+		spin_lock(&bdev_lock);
+		list_add(&bdev->bd_list, &all_bdevs);
+		spin_unlock(&bdev_lock);
+		unlock_new_inode(inode);
+	}
+	return bdev;
+}
+
+EXPORT_SYMBOL(bdget);
+
+long nr_blockdev_pages(void)
+{
+	struct list_head *p;
+	long ret = 0;
+	spin_lock(&bdev_lock);
+	list_for_each(p, &all_bdevs) {
+		struct block_device *bdev;
+		bdev = list_entry(p, struct block_device, bd_list);
+		ret += bdev->bd_inode->i_mapping->nrpages;
+	}
+	spin_unlock(&bdev_lock);
+	return ret;
+}
+
+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 && igrab(bdev->bd_inode)) {
+		spin_unlock(&bdev_lock);
+		return bdev;
+	}
+	spin_unlock(&bdev_lock);
+	bdev = bdget(inode->i_rdev);
+	if (bdev) {
+		spin_lock(&bdev_lock);
+		if (inode->i_bdev)
+			__bd_forget(inode);
+		inode->i_bdev = bdev;
+		inode->i_mapping = bdev->bd_inode->i_mapping;
+		list_add(&inode->i_devices, &bdev->bd_inodes);
+		spin_unlock(&bdev_lock);
+	}
+	return bdev;
+}
+
+/* Call when you free inode */
+
+void bd_forget(struct inode *inode)
+{
+	spin_lock(&bdev_lock);
+	if (inode->i_bdev)
+		__bd_forget(inode);
+	spin_unlock(&bdev_lock);
+}
+
+int bd_claim(struct block_device *bdev, void *holder)
+{
+	int res;
+	spin_lock(&bdev_lock);
+
+	/* first decide result */
+	if (bdev->bd_holder == holder)
+		res = 0;	 /* already a holder */
+	else if (bdev->bd_holder != NULL)
+		res = -EBUSY; 	 /* held by someone else */
+	else if (bdev->bd_contains == bdev)
+		res = 0;  	 /* is a whole device which isn't held */
+
+	else if (bdev->bd_contains->bd_holder == bd_claim)
+		res = 0; 	 /* is a partition of a device that is being partitioned */
+	else if (bdev->bd_contains->bd_holder != NULL)
+		res = -EBUSY;	 /* is a partition of a held device */
+	else
+		res = 0;	 /* is a partition of an un-held device */
+
+	/* now impose change */
+	if (res==0) {
+		/* note that for a whole device bd_holders
+		 * will be incremented twice, and bd_holder will
+		 * be set to bd_claim before being set to holder
+		 */
+		bdev->bd_contains->bd_holders ++;
+		bdev->bd_contains->bd_holder = bd_claim;
+		bdev->bd_holders++;
+		bdev->bd_holder = holder;
+	}
+	spin_unlock(&bdev_lock);
+	return res;
+}
+
+EXPORT_SYMBOL(bd_claim);
+
+void bd_release(struct block_device *bdev)
+{
+	spin_lock(&bdev_lock);
+	if (!--bdev->bd_contains->bd_holders)
+		bdev->bd_contains->bd_holder = NULL;
+	if (!--bdev->bd_holders)
+		bdev->bd_holder = NULL;
+	spin_unlock(&bdev_lock);
+}
+
+EXPORT_SYMBOL(bd_release);
+
+/*
+ * Tries to open block device by device number.  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.
+ */
+struct block_device *open_by_devnum(dev_t dev, unsigned mode)
+{
+	struct block_device *bdev = bdget(dev);
+	int err = -ENOMEM;
+	int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;
+	if (bdev)
+		err = blkdev_get(bdev, mode, flags);
+	return err ? ERR_PTR(err) : bdev;
+}
+
+EXPORT_SYMBOL(open_by_devnum);
+
+/*
+ * This routine checks whether a removable media has been changed,
+ * and invalidates all buffer-cache-entries in that case. This
+ * is a relatively slow routine, so we have to try to minimize using
+ * it. Thus it is called only upon a 'mount' or 'open'. This
+ * is the best way of combining speed and utility, I think.
+ * People changing diskettes in the middle of an operation deserve
+ * to lose :-)
+ */
+int check_disk_change(struct block_device *bdev)
+{
+	struct gendisk *disk = bdev->bd_disk;
+	struct block_device_operations * bdops = disk->fops;
+
+	if (!bdops->media_changed)
+		return 0;
+	if (!bdops->media_changed(bdev->bd_disk))
+		return 0;
+
+	if (__invalidate_device(bdev, 0))
+		printk("VFS: busy inodes on changed media.\n");
+
+	if (bdops->revalidate_disk)
+		bdops->revalidate_disk(bdev->bd_disk);
+	if (bdev->bd_disk->minors > 1)
+		bdev->bd_invalidated = 1;
+	return 1;
+}
+
+EXPORT_SYMBOL(check_disk_change);
+
+void bd_set_size(struct block_device *bdev, loff_t size)
+{
+	unsigned bsize = bdev_hardsect_size(bdev);
+
+	bdev->bd_inode->i_size = size;
+	while (bsize < PAGE_CACHE_SIZE) {
+		if (size & bsize)
+			break;
+		bsize <<= 1;
+	}
+	bdev->bd_block_size = bsize;
+	bdev->bd_inode->i_blkbits = blksize_bits(bsize);
+}
+EXPORT_SYMBOL(bd_set_size);
+
+static int do_open(struct block_device *bdev, struct file *file)
+{
+	struct module *owner = NULL;
+	struct gendisk *disk;
+	int ret = -ENXIO;
+	int part;
+
+	file->f_mapping = bdev->bd_inode->i_mapping;
+	lock_kernel();
+	disk = get_gendisk(bdev->bd_dev, &part);
+	if (!disk) {
+		unlock_kernel();
+		bdput(bdev);
+		return ret;
+	}
+	owner = disk->fops->owner;
+
+	down(&bdev->bd_sem);
+	if (!bdev->bd_openers) {
+		bdev->bd_disk = disk;
+		bdev->bd_contains = bdev;
+		if (!part) {
+			struct backing_dev_info *bdi;
+			if (disk->fops->open) {
+				ret = disk->fops->open(bdev->bd_inode, file);
+				if (ret)
+					goto out_first;
+			}
+			if (!bdev->bd_openers) {
+				bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
+				bdi = blk_get_backing_dev_info(bdev);
+				if (bdi == NULL)
+					bdi = &default_backing_dev_info;
+				bdev->bd_inode->i_data.backing_dev_info = bdi;
+			}
+			if (bdev->bd_invalidated)
+				rescan_partitions(disk, bdev);
+		} else {
+			struct hd_struct *p;
+			struct block_device *whole;
+			whole = bdget_disk(disk, 0);
+			ret = -ENOMEM;
+			if (!whole)
+				goto out_first;
+			ret = blkdev_get(whole, file->f_mode, file->f_flags);
+			if (ret)
+				goto out_first;
+			bdev->bd_contains = whole;
+			down(&whole->bd_sem);
+			whole->bd_part_count++;
+			p = disk->part[part - 1];
+			bdev->bd_inode->i_data.backing_dev_info =
+			   whole->bd_inode->i_data.backing_dev_info;
+			if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) {
+				whole->bd_part_count--;
+				up(&whole->bd_sem);
+				ret = -ENXIO;
+				goto out_first;
+			}
+			kobject_get(&p->kobj);
+			bdev->bd_part = p;
+			bd_set_size(bdev, (loff_t) p->nr_sects << 9);
+			up(&whole->bd_sem);
+		}
+	} else {
+		put_disk(disk);
+		module_put(owner);
+		if (bdev->bd_contains == bdev) {
+			if (bdev->bd_disk->fops->open) {
+				ret = bdev->bd_disk->fops->open(bdev->bd_inode, file);
+				if (ret)
+					goto out;
+			}
+			if (bdev->bd_invalidated)
+				rescan_partitions(bdev->bd_disk, bdev);
+		} else {
+			down(&bdev->bd_contains->bd_sem);
+			bdev->bd_contains->bd_part_count++;
+			up(&bdev->bd_contains->bd_sem);
+		}
+	}
+	bdev->bd_openers++;
+	up(&bdev->bd_sem);
+	unlock_kernel();
+	return 0;
+
+out_first:
+	bdev->bd_disk = NULL;
+	bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
+	if (bdev != bdev->bd_contains)
+		blkdev_put(bdev->bd_contains);
+	bdev->bd_contains = NULL;
+	put_disk(disk);
+	module_put(owner);
+out:
+	up(&bdev->bd_sem);
+	unlock_kernel();
+	if (ret)
+		bdput(bdev);
+	return ret;
+}
+
+int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
+{
+	/*
+	 * This crockload is due to bad choice of ->open() type.
+	 * It will go away.
+	 * For now, block device ->open() routine must _not_
+	 * examine anything in 'inode' argument except ->i_rdev.
+	 */
+	struct file fake_file = {};
+	struct dentry fake_dentry = {};
+	fake_file.f_mode = mode;
+	fake_file.f_flags = flags;
+	fake_file.f_dentry = &fake_dentry;
+	fake_dentry.d_inode = bdev->bd_inode;
+
+	return do_open(bdev, &fake_file);
+}
+
+EXPORT_SYMBOL(blkdev_get);
+
+static int blkdev_open(struct inode * inode, struct file * filp)
+{
+	struct block_device *bdev;
+	int res;
+
+	/*
+	 * Preserve backwards compatibility and allow large file access
+	 * even if userspace doesn't ask for it explicitly. Some mkfs
+	 * binary needs it. We might want to drop this workaround
+	 * during an unstable branch.
+	 */
+	filp->f_flags |= O_LARGEFILE;
+
+	bdev = bd_acquire(inode);
+
+	res = do_open(bdev, filp);
+	if (res)
+		return res;
+
+	if (!(filp->f_flags & O_EXCL) )
+		return 0;
+
+	if (!(res = bd_claim(bdev, filp)))
+		return 0;
+
+	blkdev_put(bdev);
+	return res;
+}
+
+int blkdev_put(struct block_device *bdev)
+{
+	int ret = 0;
+	struct inode *bd_inode = bdev->bd_inode;
+	struct gendisk *disk = bdev->bd_disk;
+
+	down(&bdev->bd_sem);
+	lock_kernel();
+	if (!--bdev->bd_openers) {
+		sync_blockdev(bdev);
+		kill_bdev(bdev);
+	}
+	if (bdev->bd_contains == bdev) {
+		if (disk->fops->release)
+			ret = disk->fops->release(bd_inode, NULL);
+	} else {
+		down(&bdev->bd_contains->bd_sem);
+		bdev->bd_contains->bd_part_count--;
+		up(&bdev->bd_contains->bd_sem);
+	}
+	if (!bdev->bd_openers) {
+		struct module *owner = disk->fops->owner;
+
+		put_disk(disk);
+		module_put(owner);
+
+		if (bdev->bd_contains != bdev) {
+			kobject_put(&bdev->bd_part->kobj);
+			bdev->bd_part = NULL;
+		}
+		bdev->bd_disk = NULL;
+		bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
+		if (bdev != bdev->bd_contains) {
+			blkdev_put(bdev->bd_contains);
+		}
+		bdev->bd_contains = NULL;
+	}
+	unlock_kernel();
+	up(&bdev->bd_sem);
+	bdput(bdev);
+	return ret;
+}
+
+EXPORT_SYMBOL(blkdev_put);
+
+static int blkdev_close(struct inode * inode, struct file * filp)
+{
+	struct block_device *bdev = I_BDEV(filp->f_mapping->host);
+	if (bdev->bd_holder == filp)
+		bd_release(bdev);
+	return blkdev_put(bdev);
+}
+
+static ssize_t blkdev_file_write(struct file *file, const char __user *buf,
+				   size_t count, loff_t *ppos)
+{
+	struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count };
+
+	return generic_file_write_nolock(file, &local_iov, 1, ppos);
+}
+
+static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf,
+				   size_t count, loff_t pos)
+{
+	struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count };
+
+	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
+}
+
+static int block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
+			unsigned long arg)
+{
+	return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
+}
+
+struct address_space_operations def_blk_aops = {
+	.readpage	= blkdev_readpage,
+	.writepage	= blkdev_writepage,
+	.sync_page	= block_sync_page,
+	.prepare_write	= blkdev_prepare_write,
+	.commit_write	= blkdev_commit_write,
+	.writepages	= generic_writepages,
+	.direct_IO	= blkdev_direct_IO,
+};
+
+struct file_operations def_blk_fops = {
+	.open		= blkdev_open,
+	.release	= blkdev_close,
+	.llseek		= block_llseek,
+	.read		= generic_file_read,
+	.write		= blkdev_file_write,
+  	.aio_read	= generic_file_aio_read,
+  	.aio_write	= blkdev_file_aio_write, 
+	.mmap		= generic_file_mmap,
+	.fsync		= block_fsync,
+	.ioctl		= block_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= compat_blkdev_ioctl,
+#endif
+	.readv		= generic_file_readv,
+	.writev		= generic_file_write_nolock,
+	.sendfile	= generic_file_sendfile,
+};
+
+int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
+{
+	int res;
+	mm_segment_t old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg);
+	set_fs(old_fs);
+	return res;
+}
+
+EXPORT_SYMBOL(ioctl_by_bdev);
+
+/**
+ * lookup_bdev  - lookup a struct block_device by name
+ *
+ * @path:	special file representing the block device
+ *
+ * Get a reference to the blockdevice at @path in the current
+ * namespace if possible and return it.  Return ERR_PTR(error)
+ * otherwise.
+ */
+struct block_device *lookup_bdev(const char *path)
+{
+	struct block_device *bdev;
+	struct inode *inode;
+	struct nameidata nd;
+	int error;
+
+	if (!path || !*path)
+		return ERR_PTR(-EINVAL);
+
+	error = path_lookup(path, LOOKUP_FOLLOW, &nd);
+	if (error)
+		return ERR_PTR(error);
+
+	inode = nd.dentry->d_inode;
+	error = -ENOTBLK;
+	if (!S_ISBLK(inode->i_mode))
+		goto fail;
+	error = -EACCES;
+	if (nd.mnt->mnt_flags & MNT_NODEV)
+		goto fail;
+	error = -ENOMEM;
+	bdev = bd_acquire(inode);
+	if (!bdev)
+		goto fail;
+out:
+	path_release(&nd);
+	return bdev;
+fail:
+	bdev = ERR_PTR(error);
+	goto out;
+}
+
+/**
+ * open_bdev_excl  -  open a block device by name and set it up for use
+ *
+ * @path:	special file representing the block device
+ * @flags:	%MS_RDONLY for opening read-only
+ * @holder:	owner for exclusion
+ *
+ * Open the blockdevice described by the special file at @path, claim it
+ * for the @holder.
+ */
+struct block_device *open_bdev_excl(const char *path, int flags, void *holder)
+{
+	struct block_device *bdev;
+	mode_t mode = FMODE_READ;
+	int error = 0;
+
+	bdev = lookup_bdev(path);
+	if (IS_ERR(bdev))
+		return bdev;
+
+	if (!(flags & MS_RDONLY))
+		mode |= FMODE_WRITE;
+	error = blkdev_get(bdev, mode, 0);
+	if (error)
+		return ERR_PTR(error);
+	error = -EACCES;
+	if (!(flags & MS_RDONLY) && bdev_read_only(bdev))
+		goto blkdev_put;
+	error = bd_claim(bdev, holder);
+	if (error)
+		goto blkdev_put;
+
+	return bdev;
+	
+blkdev_put:
+	blkdev_put(bdev);
+	return ERR_PTR(error);
+}
+
+EXPORT_SYMBOL(open_bdev_excl);
+
+/**
+ * close_bdev_excl  -  release a blockdevice openen by open_bdev_excl()
+ *
+ * @bdev:	blockdevice to close
+ *
+ * This is the counterpart to open_bdev_excl().
+ */
+void close_bdev_excl(struct block_device *bdev)
+{
+	bd_release(bdev);
+	blkdev_put(bdev);
+}
+
+EXPORT_SYMBOL(close_bdev_excl);