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block_dev.c
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/*
* 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)
{
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_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,
struct buffer_head *bh, int create)
{
sector_t end_block = max_block(I_BDEV(inode));
unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
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;
mutex_lock(&bd_inode->i_mutex);
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;
}
mutex_unlock(&bd_inode->i_mutex);
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 __read_mostly;
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));
mutex_init(&bdev->bd_mutex);
mutex_init(&bdev->bd_mount_mutex);
INIT_LIST_HEAD(&bdev->bd_inodes);
INIT_LIST_HEAD(&bdev->bd_list);
#ifdef CONFIG_SYSFS
INIT_LIST_HEAD(&bdev->bd_holder_list);
#endif
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 int bd_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
}
static struct file_system_type bd_type = {
.name = "bdev",
.get_sb = bd_get_sb,
.kill_sb = kill_anon_super,
};
static struct vfsmount *bd_mnt __read_mostly;
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_MEM_SPREAD|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) {
atomic_inc(&bdev->bd_inode->i_count);
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) {
/*
* We take an additional bd_inode->i_count for inode,
* and it's released in clear_inode() of inode.
* So, we can access it via ->i_mapping always
* without igrab().
*/
atomic_inc(&bdev->bd_inode->i_count);
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)
{
struct block_device *bdev = NULL;
spin_lock(&bdev_lock);
if (inode->i_bdev) {
if (inode->i_sb != blockdev_superblock)
bdev = inode->i_bdev;
__bd_forget(inode);
}
spin_unlock(&bdev_lock);
if (bdev)
iput(bdev->bd_inode);
}
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);
#ifdef CONFIG_SYSFS
/*
* Functions for bd_claim_by_kobject / bd_release_from_kobject
*
* If a kobject is passed to bd_claim_by_kobject()
* and the kobject has a parent directory,
* following symlinks are created:
* o from the kobject to the claimed bdev
* o from "holders" directory of the bdev to the parent of the kobject
* bd_release_from_kobject() removes these symlinks.
*
* Example:
* If /dev/dm-0 maps to /dev/sda, kobject corresponding to
* /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
* /sys/block/dm-0/slaves/sda --> /sys/block/sda
* /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
*/
static struct kobject *bdev_get_kobj(struct block_device *bdev)
{
if (bdev->bd_contains != bdev)
return kobject_get(&bdev->bd_part->kobj);
else
return kobject_get(&bdev->bd_disk->kobj);
}
static struct kobject *bdev_get_holder(struct block_device *bdev)
{
if (bdev->bd_contains != bdev)
return kobject_get(bdev->bd_part->holder_dir);
else
return kobject_get(bdev->bd_disk->holder_dir);
}
static void add_symlink(struct kobject *from, struct kobject *to)
{
if (!from || !to)
return;
sysfs_create_link(from, to, kobject_name(to));
}
static void del_symlink(struct kobject *from, struct kobject *to)
{
if (!from || !to)
return;
sysfs_remove_link(from, kobject_name(to));
}
/*
* 'struct bd_holder' contains pointers to kobjects symlinked by
* bd_claim_by_kobject.
* It's connected to bd_holder_list which is protected by bdev->bd_sem.
*/
struct bd_holder {
struct list_head list; /* chain of holders of the bdev */
int count; /* references from the holder */
struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
struct kobject *hdev; /* e.g. "/block/dm-0" */
struct kobject *hdir; /* e.g. "/block/sda/holders" */
struct kobject *sdev; /* e.g. "/block/sda" */
};
/*
* Get references of related kobjects at once.
* Returns 1 on success. 0 on failure.
*
* Should call bd_holder_release_dirs() after successful use.
*/
static int bd_holder_grab_dirs(struct block_device *bdev,
struct bd_holder *bo)
{
if (!bdev || !bo)
return 0;
bo->sdir = kobject_get(bo->sdir);
if (!bo->sdir)
return 0;
bo->hdev = kobject_get(bo->sdir->parent);
if (!bo->hdev)
goto fail_put_sdir;
bo->sdev = bdev_get_kobj(bdev);
if (!bo->sdev)
goto fail_put_hdev;
bo->hdir = bdev_get_holder(bdev);
if (!bo->hdir)
goto fail_put_sdev;
return 1;
fail_put_sdev:
kobject_put(bo->sdev);
fail_put_hdev:
kobject_put(bo->hdev);
fail_put_sdir:
kobject_put(bo->sdir);
return 0;
}
/* Put references of related kobjects at once. */
static void bd_holder_release_dirs(struct bd_holder *bo)
{
kobject_put(bo->hdir);
kobject_put(bo->sdev);
kobject_put(bo->hdev);
kobject_put(bo->sdir);
}
static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
{
struct bd_holder *bo;
bo = kzalloc(sizeof(*bo), GFP_KERNEL);
if (!bo)
return NULL;
bo->count = 1;
bo->sdir = kobj;
return bo;
}
static void free_bd_holder(struct bd_holder *bo)
{
kfree(bo);
}
/**
* add_bd_holder - create sysfs symlinks for bd_claim() relationship
*
* @bdev: block device to be bd_claimed
* @bo: preallocated and initialized by alloc_bd_holder()
*
* If there is no matching entry with @bo in @bdev->bd_holder_list,
* add @bo to the list, create symlinks.
*
* Returns 1 if @bo was added to the list.
* Returns 0 if @bo wasn't used by any reason and should be freed.
*/
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
{
struct bd_holder *tmp;
if (!bo)
return 0;
list_for_each_entry(tmp, &bdev->bd_holder_list, list) {
if (tmp->sdir == bo->sdir) {
tmp->count++;
return 0;
}
}
if (!bd_holder_grab_dirs(bdev, bo))
return 0;
add_symlink(bo->sdir, bo->sdev);
add_symlink(bo->hdir, bo->hdev);
list_add_tail(&bo->list, &bdev->bd_holder_list);
return 1;
}
/**
* del_bd_holder - delete sysfs symlinks for bd_claim() relationship
*
* @bdev: block device to be bd_claimed
* @kobj: holder's kobject
*
* If there is matching entry with @kobj in @bdev->bd_holder_list
* and no other bd_claim() from the same kobject,
* remove the struct bd_holder from the list, delete symlinks for it.
*
* Returns a pointer to the struct bd_holder when it's removed from the list
* and ready to be freed.
* Returns NULL if matching claim isn't found or there is other bd_claim()
* by the same kobject.
*/
static struct bd_holder *del_bd_holder(struct block_device *bdev,
struct kobject *kobj)
{
struct bd_holder *bo;
list_for_each_entry(bo, &bdev->bd_holder_list, list) {
if (bo->sdir == kobj) {
bo->count--;
BUG_ON(bo->count < 0);
if (!bo->count) {
list_del(&bo->list);
del_symlink(bo->sdir, bo->sdev);
del_symlink(bo->hdir, bo->hdev);
bd_holder_release_dirs(bo);
return bo;
}
break;
}
}
return NULL;
}
/**
* bd_claim_by_kobject - bd_claim() with additional kobject signature
*
* @bdev: block device to be claimed
* @holder: holder's signature
* @kobj: holder's kobject
*
* Do bd_claim() and if it succeeds, create sysfs symlinks between
* the bdev and the holder's kobject.
* Use bd_release_from_kobject() when relesing the claimed bdev.
*
* Returns 0 on success. (same as bd_claim())
* Returns errno on failure.
*/
static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
struct kobject *kobj)
{
int res;
struct bd_holder *bo;
if (!kobj)
return -EINVAL;
bo = alloc_bd_holder(kobj);
if (!bo)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
res = bd_claim(bdev, holder);
if (res || !add_bd_holder(bdev, bo))
free_bd_holder(bo);
mutex_unlock(&bdev->bd_mutex);
return res;
}
/**
* bd_release_from_kobject - bd_release() with additional kobject signature
*
* @bdev: block device to be released
* @kobj: holder's kobject
*
* Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
*/
static void bd_release_from_kobject(struct block_device *bdev,
struct kobject *kobj)
{
struct bd_holder *bo;
if (!kobj)
return;
mutex_lock(&bdev->bd_mutex);
bd_release(bdev);
if ((bo = del_bd_holder(bdev, kobj)))
free_bd_holder(bo);
mutex_unlock(&bdev->bd_mutex);
}
/**
* bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
*
* @bdev: block device to be claimed
* @holder: holder's signature
* @disk: holder's gendisk
*
* Call bd_claim_by_kobject() with getting @disk->slave_dir.
*/
int bd_claim_by_disk(struct block_device *bdev, void *holder,
struct gendisk *disk)
{
return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
}
EXPORT_SYMBOL_GPL(bd_claim_by_disk);
/**
* bd_release_from_disk - wrapper function for bd_release_from_kobject()
*
* @bdev: block device to be claimed
* @disk: holder's gendisk
*
* Call bd_release_from_kobject() and put @disk->slave_dir.
*/
void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
{
bd_release_from_kobject(bdev, disk->slave_dir);
kobject_put(disk->slave_dir);
}
EXPORT_SYMBOL_GPL(bd_release_from_disk);
#endif
/*
* 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))
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;
mutex_lock(&bdev->bd_mutex);
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;
mutex_lock(&whole->bd_mutex);
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--;
mutex_unlock(&whole->bd_mutex);
ret = -ENXIO;
goto out_first;
}
kobject_get(&p->kobj);
bdev->bd_part = p;
bd_set_size(bdev, (loff_t) p->nr_sects << 9);
mutex_unlock(&whole->bd_mutex);
}
} 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 {
mutex_lock(&bdev->bd_contains->bd_mutex);
bdev->bd_contains->bd_part_count++;
mutex_unlock(&bdev->bd_contains->bd_mutex);
}
}
bdev->bd_openers++;
mutex_unlock(&bdev->bd_mutex);
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:
mutex_unlock(&bdev->bd_mutex);
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;
/*