1238 lines
29 KiB
C
1238 lines
29 KiB
C
/*
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* linux/fs/block_dev.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
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*/
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/fcntl.h>
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#include <linux/slab.h>
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#include <linux/kmod.h>
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#include <linux/major.h>
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#include <linux/devfs_fs_kernel.h>
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#include <linux/smp_lock.h>
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#include <linux/highmem.h>
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#include <linux/blkdev.h>
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#include <linux/module.h>
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#include <linux/blkpg.h>
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#include <linux/buffer_head.h>
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#include <linux/mpage.h>
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#include <linux/mount.h>
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#include <linux/uio.h>
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#include <linux/namei.h>
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#include <asm/uaccess.h>
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struct bdev_inode {
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struct block_device bdev;
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struct inode vfs_inode;
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};
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static inline struct bdev_inode *BDEV_I(struct inode *inode)
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{
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return container_of(inode, struct bdev_inode, vfs_inode);
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}
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inline struct block_device *I_BDEV(struct inode *inode)
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{
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return &BDEV_I(inode)->bdev;
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}
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EXPORT_SYMBOL(I_BDEV);
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static sector_t max_block(struct block_device *bdev)
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{
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sector_t retval = ~((sector_t)0);
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loff_t sz = i_size_read(bdev->bd_inode);
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if (sz) {
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unsigned int size = block_size(bdev);
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unsigned int sizebits = blksize_bits(size);
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retval = (sz >> sizebits);
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}
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return retval;
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}
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/* Kill _all_ buffers, dirty or not.. */
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static void kill_bdev(struct block_device *bdev)
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{
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invalidate_bdev(bdev, 1);
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truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
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}
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int set_blocksize(struct block_device *bdev, int size)
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{
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/* Size must be a power of two, and between 512 and PAGE_SIZE */
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if (size > PAGE_SIZE || size < 512 || (size & (size-1)))
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return -EINVAL;
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/* Size cannot be smaller than the size supported by the device */
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if (size < bdev_hardsect_size(bdev))
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return -EINVAL;
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/* Don't change the size if it is same as current */
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if (bdev->bd_block_size != size) {
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sync_blockdev(bdev);
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bdev->bd_block_size = size;
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bdev->bd_inode->i_blkbits = blksize_bits(size);
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kill_bdev(bdev);
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}
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return 0;
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}
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EXPORT_SYMBOL(set_blocksize);
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int sb_set_blocksize(struct super_block *sb, int size)
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{
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if (set_blocksize(sb->s_bdev, size))
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return 0;
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/* If we get here, we know size is power of two
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* and it's value is between 512 and PAGE_SIZE */
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sb->s_blocksize = size;
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sb->s_blocksize_bits = blksize_bits(size);
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return sb->s_blocksize;
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}
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EXPORT_SYMBOL(sb_set_blocksize);
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int sb_min_blocksize(struct super_block *sb, int size)
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{
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int minsize = bdev_hardsect_size(sb->s_bdev);
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if (size < minsize)
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size = minsize;
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return sb_set_blocksize(sb, size);
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}
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EXPORT_SYMBOL(sb_min_blocksize);
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static int
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blkdev_get_block(struct inode *inode, sector_t iblock,
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struct buffer_head *bh, int create)
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{
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if (iblock >= max_block(I_BDEV(inode))) {
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if (create)
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return -EIO;
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/*
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* for reads, we're just trying to fill a partial page.
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* return a hole, they will have to call get_block again
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* before they can fill it, and they will get -EIO at that
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* time
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*/
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return 0;
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}
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bh->b_bdev = I_BDEV(inode);
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bh->b_blocknr = iblock;
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set_buffer_mapped(bh);
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return 0;
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}
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static int
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blkdev_get_blocks(struct inode *inode, sector_t iblock,
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struct buffer_head *bh, int create)
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{
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sector_t end_block = max_block(I_BDEV(inode));
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unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
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if ((iblock + max_blocks) > end_block) {
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max_blocks = end_block - iblock;
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if ((long)max_blocks <= 0) {
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if (create)
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return -EIO; /* write fully beyond EOF */
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/*
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* It is a read which is fully beyond EOF. We return
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* a !buffer_mapped buffer
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*/
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max_blocks = 0;
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}
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}
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bh->b_bdev = I_BDEV(inode);
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bh->b_blocknr = iblock;
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bh->b_size = max_blocks << inode->i_blkbits;
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if (max_blocks)
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set_buffer_mapped(bh);
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return 0;
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}
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static ssize_t
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blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
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loff_t offset, unsigned long nr_segs)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_mapping->host;
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return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
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iov, offset, nr_segs, blkdev_get_blocks, NULL);
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}
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static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
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{
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return block_write_full_page(page, blkdev_get_block, wbc);
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}
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static int blkdev_readpage(struct file * file, struct page * page)
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{
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return block_read_full_page(page, blkdev_get_block);
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}
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static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
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{
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return block_prepare_write(page, from, to, blkdev_get_block);
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}
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static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to)
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{
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return block_commit_write(page, from, to);
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}
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/*
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* private llseek:
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* for a block special file file->f_dentry->d_inode->i_size is zero
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* so we compute the size by hand (just as in block_read/write above)
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*/
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static loff_t block_llseek(struct file *file, loff_t offset, int origin)
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{
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struct inode *bd_inode = file->f_mapping->host;
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loff_t size;
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loff_t retval;
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mutex_lock(&bd_inode->i_mutex);
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size = i_size_read(bd_inode);
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switch (origin) {
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case 2:
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offset += size;
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break;
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case 1:
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offset += file->f_pos;
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}
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retval = -EINVAL;
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if (offset >= 0 && offset <= size) {
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if (offset != file->f_pos) {
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file->f_pos = offset;
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}
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retval = offset;
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}
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mutex_unlock(&bd_inode->i_mutex);
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return retval;
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}
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/*
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* Filp is never NULL; the only case when ->fsync() is called with
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* NULL first argument is nfsd_sync_dir() and that's not a directory.
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*/
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static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
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{
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return sync_blockdev(I_BDEV(filp->f_mapping->host));
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}
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/*
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* pseudo-fs
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*/
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static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
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static kmem_cache_t * bdev_cachep __read_mostly;
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static struct inode *bdev_alloc_inode(struct super_block *sb)
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{
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struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL);
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if (!ei)
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return NULL;
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return &ei->vfs_inode;
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}
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static void bdev_destroy_inode(struct inode *inode)
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{
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struct bdev_inode *bdi = BDEV_I(inode);
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bdi->bdev.bd_inode_backing_dev_info = NULL;
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kmem_cache_free(bdev_cachep, bdi);
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}
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static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
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{
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struct bdev_inode *ei = (struct bdev_inode *) foo;
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struct block_device *bdev = &ei->bdev;
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if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
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SLAB_CTOR_CONSTRUCTOR)
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{
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memset(bdev, 0, sizeof(*bdev));
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mutex_init(&bdev->bd_mutex);
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mutex_init(&bdev->bd_mount_mutex);
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INIT_LIST_HEAD(&bdev->bd_inodes);
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INIT_LIST_HEAD(&bdev->bd_list);
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#ifdef CONFIG_SYSFS
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INIT_LIST_HEAD(&bdev->bd_holder_list);
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#endif
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inode_init_once(&ei->vfs_inode);
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}
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}
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static inline void __bd_forget(struct inode *inode)
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{
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list_del_init(&inode->i_devices);
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inode->i_bdev = NULL;
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inode->i_mapping = &inode->i_data;
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}
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static void bdev_clear_inode(struct inode *inode)
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{
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struct block_device *bdev = &BDEV_I(inode)->bdev;
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struct list_head *p;
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spin_lock(&bdev_lock);
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while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
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__bd_forget(list_entry(p, struct inode, i_devices));
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}
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list_del_init(&bdev->bd_list);
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spin_unlock(&bdev_lock);
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}
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static struct super_operations bdev_sops = {
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.statfs = simple_statfs,
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.alloc_inode = bdev_alloc_inode,
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.destroy_inode = bdev_destroy_inode,
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.drop_inode = generic_delete_inode,
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.clear_inode = bdev_clear_inode,
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};
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static struct super_block *bd_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576);
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}
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static struct file_system_type bd_type = {
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.name = "bdev",
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.get_sb = bd_get_sb,
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.kill_sb = kill_anon_super,
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};
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static struct vfsmount *bd_mnt __read_mostly;
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struct super_block *blockdev_superblock;
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void __init bdev_cache_init(void)
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{
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int err;
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bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
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0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD|SLAB_PANIC),
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init_once, NULL);
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err = register_filesystem(&bd_type);
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if (err)
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panic("Cannot register bdev pseudo-fs");
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bd_mnt = kern_mount(&bd_type);
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err = PTR_ERR(bd_mnt);
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if (IS_ERR(bd_mnt))
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panic("Cannot create bdev pseudo-fs");
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blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
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}
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/*
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* Most likely _very_ bad one - but then it's hardly critical for small
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* /dev and can be fixed when somebody will need really large one.
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* Keep in mind that it will be fed through icache hash function too.
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*/
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static inline unsigned long hash(dev_t dev)
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{
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return MAJOR(dev)+MINOR(dev);
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}
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static int bdev_test(struct inode *inode, void *data)
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{
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return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
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}
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static int bdev_set(struct inode *inode, void *data)
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{
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BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
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return 0;
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}
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static LIST_HEAD(all_bdevs);
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struct block_device *bdget(dev_t dev)
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{
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struct block_device *bdev;
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struct inode *inode;
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inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
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bdev_test, bdev_set, &dev);
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if (!inode)
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return NULL;
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bdev = &BDEV_I(inode)->bdev;
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if (inode->i_state & I_NEW) {
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bdev->bd_contains = NULL;
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bdev->bd_inode = inode;
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bdev->bd_block_size = (1 << inode->i_blkbits);
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bdev->bd_part_count = 0;
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bdev->bd_invalidated = 0;
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inode->i_mode = S_IFBLK;
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inode->i_rdev = dev;
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inode->i_bdev = bdev;
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inode->i_data.a_ops = &def_blk_aops;
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mapping_set_gfp_mask(&inode->i_data, GFP_USER);
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inode->i_data.backing_dev_info = &default_backing_dev_info;
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spin_lock(&bdev_lock);
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list_add(&bdev->bd_list, &all_bdevs);
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spin_unlock(&bdev_lock);
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unlock_new_inode(inode);
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}
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return bdev;
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}
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EXPORT_SYMBOL(bdget);
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long nr_blockdev_pages(void)
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{
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struct list_head *p;
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long ret = 0;
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spin_lock(&bdev_lock);
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list_for_each(p, &all_bdevs) {
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struct block_device *bdev;
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bdev = list_entry(p, struct block_device, bd_list);
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ret += bdev->bd_inode->i_mapping->nrpages;
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}
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spin_unlock(&bdev_lock);
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return ret;
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}
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void bdput(struct block_device *bdev)
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{
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iput(bdev->bd_inode);
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}
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EXPORT_SYMBOL(bdput);
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static struct block_device *bd_acquire(struct inode *inode)
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{
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struct block_device *bdev;
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spin_lock(&bdev_lock);
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bdev = inode->i_bdev;
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if (bdev) {
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atomic_inc(&bdev->bd_inode->i_count);
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spin_unlock(&bdev_lock);
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return bdev;
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}
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spin_unlock(&bdev_lock);
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bdev = bdget(inode->i_rdev);
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if (bdev) {
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spin_lock(&bdev_lock);
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if (!inode->i_bdev) {
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/*
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* We take an additional bd_inode->i_count for inode,
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* and it's released in clear_inode() of inode.
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* So, we can access it via ->i_mapping always
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* without igrab().
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*/
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atomic_inc(&bdev->bd_inode->i_count);
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inode->i_bdev = bdev;
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inode->i_mapping = bdev->bd_inode->i_mapping;
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list_add(&inode->i_devices, &bdev->bd_inodes);
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}
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spin_unlock(&bdev_lock);
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}
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return bdev;
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}
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/* Call when you free inode */
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void bd_forget(struct inode *inode)
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{
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struct block_device *bdev = NULL;
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spin_lock(&bdev_lock);
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if (inode->i_bdev) {
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if (inode->i_sb != blockdev_superblock)
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bdev = inode->i_bdev;
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__bd_forget(inode);
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}
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spin_unlock(&bdev_lock);
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if (bdev)
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iput(bdev->bd_inode);
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}
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int bd_claim(struct block_device *bdev, void *holder)
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{
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int res;
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spin_lock(&bdev_lock);
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/* first decide result */
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if (bdev->bd_holder == holder)
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res = 0; /* already a holder */
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else if (bdev->bd_holder != NULL)
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res = -EBUSY; /* held by someone else */
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else if (bdev->bd_contains == bdev)
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res = 0; /* is a whole device which isn't held */
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else if (bdev->bd_contains->bd_holder == bd_claim)
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res = 0; /* is a partition of a device that is being partitioned */
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else if (bdev->bd_contains->bd_holder != NULL)
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res = -EBUSY; /* is a partition of a held device */
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else
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res = 0; /* is a partition of an un-held device */
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/* now impose change */
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if (res==0) {
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/* note that for a whole device bd_holders
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* will be incremented twice, and bd_holder will
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* be set to bd_claim before being set to holder
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*/
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bdev->bd_contains->bd_holders ++;
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bdev->bd_contains->bd_holder = bd_claim;
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bdev->bd_holders++;
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bdev->bd_holder = holder;
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}
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spin_unlock(&bdev_lock);
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return res;
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}
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|
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EXPORT_SYMBOL(bd_claim);
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|
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void bd_release(struct block_device *bdev)
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{
|
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spin_lock(&bdev_lock);
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if (!--bdev->bd_contains->bd_holders)
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bdev->bd_contains->bd_holder = NULL;
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if (!--bdev->bd_holders)
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bdev->bd_holder = NULL;
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spin_unlock(&bdev_lock);
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}
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|
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EXPORT_SYMBOL(bd_release);
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|
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#ifdef CONFIG_SYSFS
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/*
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* Functions for bd_claim_by_kobject / bd_release_from_kobject
|
|
*
|
|
* If a kobject is passed to bd_claim_by_kobject()
|
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* 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;
|
|
|
|
/*
|
|
* 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;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
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 {
|
|
mutex_lock(&bdev->bd_contains->bd_mutex);
|
|
bdev->bd_contains->bd_part_count--;
|
|
mutex_unlock(&bdev->bd_contains->bd_mutex);
|
|
}
|
|
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();
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
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 long block_ioctl(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,
|
|
};
|
|
|
|
const 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,
|
|
.unlocked_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,
|
|
.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);
|