android_kernel_motorola_sm6225/fs/block_dev.c
Paul Mundt 20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00

1483 lines
35 KiB
C

/*
* linux/fs/block_dev.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
*/
#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/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/writeback.h>
#include <linux/mpage.h>
#include <linux/mount.h>
#include <linux/uio.h>
#include <linux/namei.h>
#include <linux/log2.h>
#include <asm/uaccess.h>
#include "internal.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 and pagecache , dirty or not.. */
static void kill_bdev(struct block_device *bdev)
{
if (bdev->bd_inode->i_mapping->nrpages == 0)
return;
invalidate_bh_lrus();
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 || !is_power_of_2(size))
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);
}
#if 0
static int blk_end_aio(struct bio *bio, unsigned int bytes_done, int error)
{
struct kiocb *iocb = bio->bi_private;
atomic_t *bio_count = &iocb->ki_bio_count;
if (bio_data_dir(bio) == READ)
bio_check_pages_dirty(bio);
else {
bio_release_pages(bio);
bio_put(bio);
}
/* iocb->ki_nbytes stores error code from LLDD */
if (error)
iocb->ki_nbytes = -EIO;
if (atomic_dec_and_test(bio_count)) {
if ((long)iocb->ki_nbytes < 0)
aio_complete(iocb, iocb->ki_nbytes, 0);
else
aio_complete(iocb, iocb->ki_left, 0);
}
return 0;
}
#define VEC_SIZE 16
struct pvec {
unsigned short nr;
unsigned short idx;
struct page *page[VEC_SIZE];
};
#define PAGES_SPANNED(addr, len) \
(DIV_ROUND_UP((addr) + (len), PAGE_SIZE) - (addr) / PAGE_SIZE);
/*
* get page pointer for user addr, we internally cache struct page array for
* (addr, count) range in pvec to avoid frequent call to get_user_pages. If
* internal page list is exhausted, a batch count of up to VEC_SIZE is used
* to get next set of page struct.
*/
static struct page *blk_get_page(unsigned long addr, size_t count, int rw,
struct pvec *pvec)
{
int ret, nr_pages;
if (pvec->idx == pvec->nr) {
nr_pages = PAGES_SPANNED(addr, count);
nr_pages = min(nr_pages, VEC_SIZE);
down_read(&current->mm->mmap_sem);
ret = get_user_pages(current, current->mm, addr, nr_pages,
rw == READ, 0, pvec->page, NULL);
up_read(&current->mm->mmap_sem);
if (ret < 0)
return ERR_PTR(ret);
pvec->nr = ret;
pvec->idx = 0;
}
return pvec->page[pvec->idx++];
}
/* return a page back to pvec array */
static void blk_unget_page(struct page *page, struct pvec *pvec)
{
pvec->page[--pvec->idx] = page;
}
static ssize_t
blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t pos, unsigned long nr_segs)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
unsigned blkbits = blksize_bits(bdev_hardsect_size(I_BDEV(inode)));
unsigned blocksize_mask = (1 << blkbits) - 1;
unsigned long seg = 0; /* iov segment iterator */
unsigned long nvec; /* number of bio vec needed */
unsigned long cur_off; /* offset into current page */
unsigned long cur_len; /* I/O len of current page, up to PAGE_SIZE */
unsigned long addr; /* user iovec address */
size_t count; /* user iovec len */
size_t nbytes = iocb->ki_nbytes = iocb->ki_left; /* total xfer size */
loff_t size; /* size of block device */
struct bio *bio;
atomic_t *bio_count = &iocb->ki_bio_count;
struct page *page;
struct pvec pvec;
pvec.nr = 0;
pvec.idx = 0;
if (pos & blocksize_mask)
return -EINVAL;
size = i_size_read(inode);
if (pos + nbytes > size) {
nbytes = size - pos;
iocb->ki_left = nbytes;
}
/*
* check first non-zero iov alignment, the remaining
* iov alignment is checked inside bio loop below.
*/
do {
addr = (unsigned long) iov[seg].iov_base;
count = min(iov[seg].iov_len, nbytes);
if (addr & blocksize_mask || count & blocksize_mask)
return -EINVAL;
} while (!count && ++seg < nr_segs);
atomic_set(bio_count, 1);
while (nbytes) {
/* roughly estimate number of bio vec needed */
nvec = (nbytes + PAGE_SIZE - 1) / PAGE_SIZE;
nvec = max(nvec, nr_segs - seg);
nvec = min(nvec, (unsigned long) BIO_MAX_PAGES);
/* bio_alloc should not fail with GFP_KERNEL flag */
bio = bio_alloc(GFP_KERNEL, nvec);
bio->bi_bdev = I_BDEV(inode);
bio->bi_end_io = blk_end_aio;
bio->bi_private = iocb;
bio->bi_sector = pos >> blkbits;
same_bio:
cur_off = addr & ~PAGE_MASK;
cur_len = PAGE_SIZE - cur_off;
if (count < cur_len)
cur_len = count;
page = blk_get_page(addr, count, rw, &pvec);
if (unlikely(IS_ERR(page)))
goto backout;
if (bio_add_page(bio, page, cur_len, cur_off)) {
pos += cur_len;
addr += cur_len;
count -= cur_len;
nbytes -= cur_len;
if (count)
goto same_bio;
while (++seg < nr_segs) {
addr = (unsigned long) iov[seg].iov_base;
count = iov[seg].iov_len;
if (!count)
continue;
if (unlikely(addr & blocksize_mask ||
count & blocksize_mask)) {
page = ERR_PTR(-EINVAL);
goto backout;
}
count = min(count, nbytes);
goto same_bio;
}
} else {
blk_unget_page(page, &pvec);
}
/* bio is ready, submit it */
if (rw == READ)
bio_set_pages_dirty(bio);
atomic_inc(bio_count);
submit_bio(rw, bio);
}
completion:
iocb->ki_left -= nbytes;
nbytes = iocb->ki_left;
iocb->ki_pos += nbytes;
blk_run_address_space(inode->i_mapping);
if (atomic_dec_and_test(bio_count))
aio_complete(iocb, nbytes, 0);
return -EIOCBQUEUED;
backout:
/*
* back out nbytes count constructed so far for this bio,
* we will throw away current bio.
*/
nbytes += bio->bi_size;
bio_release_pages(bio);
bio_put(bio);
/*
* if no bio was submmitted, return the error code.
* otherwise, proceed with pending I/O completion.
*/
if (atomic_read(bio_count) == 1)
return PTR_ERR(page);
goto completion;
}
#endif
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_path.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 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;
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, struct kmem_cache * cachep, unsigned long flags)
{
struct bdev_inode *ei = (struct bdev_inode *) foo;
struct block_device *bdev = &ei->bdev;
memset(bdev, 0, sizeof(*bdev));
mutex_init(&bdev->bd_mutex);
sema_init(&bdev->bd_mount_sem, 1);
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 const 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);
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 block_device *bdev;
long ret = 0;
spin_lock(&bdev_lock);
list_for_each_entry(bdev, &all_bdevs, 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 int add_symlink(struct kobject *from, struct kobject *to)
{
if (!from || !to)
return 0;
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);
}
/**
* find_bd_holder - find matching struct bd_holder from the block device
*
* @bdev: struct block device to be searched
* @bo: target struct bd_holder
*
* Returns matching entry with @bo in @bdev->bd_holder_list.
* If found, increment the reference count and return the pointer.
* If not found, returns NULL.
*/
static struct bd_holder *find_bd_holder(struct block_device *bdev,
struct bd_holder *bo)
{
struct bd_holder *tmp;
list_for_each_entry(tmp, &bdev->bd_holder_list, list)
if (tmp->sdir == bo->sdir) {
tmp->count++;
return tmp;
}
return NULL;
}
/**
* 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()
*
* Add @bo to @bdev->bd_holder_list, create symlinks.
*
* Returns 0 if symlinks are created.
* Returns -ve if something fails.
*/
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
{
int err;
if (!bo)
return -EINVAL;
if (!bd_holder_grab_dirs(bdev, bo))
return -EBUSY;
err = add_symlink(bo->sdir, bo->sdev);
if (err)
return err;
err = add_symlink(bo->hdir, bo->hdev);
if (err) {
del_symlink(bo->sdir, bo->sdev);
return err;
}
list_add_tail(&bo->list, &bdev->bd_holder_list);
return 0;
}
/**
* 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 err;
struct bd_holder *bo, *found;
if (!kobj)
return -EINVAL;
bo = alloc_bd_holder(kobj);
if (!bo)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
err = bd_claim(bdev, holder);
if (err)
goto fail;
found = find_bd_holder(bdev, bo);
if (found)
goto fail;
err = add_bd_holder(bdev, bo);
if (err)
bd_release(bdev);
else
bo = NULL;
fail:
mutex_unlock(&bdev->bd_mutex);
free_bd_holder(bo);
return err;
}
/**
* 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)
{
if (!kobj)
return;
mutex_lock(&bdev->bd_mutex);
bd_release(bdev);
free_bd_holder(del_bd_holder(bdev, kobj));
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 __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
int for_part);
static int __blkdev_put(struct block_device *bdev, int for_part);
/*
* bd_mutex locking:
*
* mutex_lock(part->bd_mutex)
* mutex_lock_nested(whole->bd_mutex, 1)
*/
static int do_open(struct block_device *bdev, struct file *file, int for_part)
{
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_nested(&bdev->bd_mutex, for_part);
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;
BUG_ON(for_part);
ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1);
if (ret)
goto out_first;
bdev->bd_contains = whole;
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) {
ret = -ENXIO;
goto out_first;
}
kobject_get(&p->kobj);
bdev->bd_part = p;
bd_set_size(bdev, (loff_t) p->nr_sects << 9);
}
} 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);
}
}
bdev->bd_openers++;
if (for_part)
bdev->bd_part_count++;
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, 1);
bdev->bd_contains = NULL;
put_disk(disk);
module_put(owner);
out:
mutex_unlock(&bdev->bd_mutex);
unlock_kernel();
if (ret)
bdput(bdev);
return ret;
}
static int __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
int for_part)
{
/*
* 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_path.dentry = &fake_dentry;
fake_dentry.d_inode = bdev->bd_inode;
return do_open(bdev, &fake_file, for_part);
}
int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
{
return __blkdev_get(bdev, mode, flags, 0);
}
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);
if (bdev == NULL)
return -ENOMEM;
res = do_open(bdev, filp, 0);
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;
}
static int __blkdev_put(struct block_device *bdev, int for_part)
{
int ret = 0;
struct inode *bd_inode = bdev->bd_inode;
struct gendisk *disk = bdev->bd_disk;
struct block_device *victim = NULL;
mutex_lock_nested(&bdev->bd_mutex, for_part);
lock_kernel();
if (for_part)
bdev->bd_part_count--;
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);
}
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)
victim = bdev->bd_contains;
bdev->bd_contains = NULL;
}
unlock_kernel();
mutex_unlock(&bdev->bd_mutex);
bdput(bdev);
if (victim)
__blkdev_put(victim, 1);
return ret;
}
int blkdev_put(struct block_device *bdev)
{
return __blkdev_put(bdev, 0);
}
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 long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
}
const 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,
};
const struct file_operations def_blk_fops = {
.open = blkdev_open,
.release = blkdev_close,
.llseek = block_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write_nolock,
.mmap = generic_file_mmap,
.fsync = block_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_blkdev_ioctl,
#endif
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
};
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);
int __invalidate_device(struct block_device *bdev)
{
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);
drop_super(sb);
}
invalidate_bdev(bdev);
return res;
}
EXPORT_SYMBOL(__invalidate_device);