Linux-2.6.12-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!
diff --git a/fs/block_dev.c b/fs/block_dev.c
new file mode 100644
index 0000000..d19d07c
--- /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);