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![Muthu Kumar](/assets/img/avatar_default.png)
- Move open-coded filesystem magic numbers into magic.h - Rearrange magic.h so that the filesystem-related constants are grouped together. Signed-off-by: Muthukumar R <muthur@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1712 lines
42 KiB
C
1712 lines
42 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/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/device_cgroup.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/magic.h>
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#include <linux/buffer_head.h>
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#include <linux/swap.h>
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#include <linux/pagevec.h>
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#include <linux/writeback.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 <linux/log2.h>
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#include <linux/cleancache.h>
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#include <asm/uaccess.h>
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#include "internal.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 const struct address_space_operations def_blk_aops;
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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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/*
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* Move the inode from its current bdi to a new bdi. If the inode is dirty we
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* need to move it onto the dirty list of @dst so that the inode is always on
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* the right list.
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*/
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static void bdev_inode_switch_bdi(struct inode *inode,
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struct backing_dev_info *dst)
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{
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struct backing_dev_info *old = inode->i_data.backing_dev_info;
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if (unlikely(dst == old)) /* deadlock avoidance */
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return;
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bdi_lock_two(&old->wb, &dst->wb);
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spin_lock(&inode->i_lock);
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inode->i_data.backing_dev_info = dst;
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if (inode->i_state & I_DIRTY)
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list_move(&inode->i_wb_list, &dst->wb.b_dirty);
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spin_unlock(&inode->i_lock);
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spin_unlock(&old->wb.list_lock);
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spin_unlock(&dst->wb.list_lock);
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}
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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 and pagecache , dirty or not.. */
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void kill_bdev(struct block_device *bdev)
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{
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struct address_space *mapping = bdev->bd_inode->i_mapping;
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if (mapping->nrpages == 0)
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return;
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invalidate_bh_lrus();
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truncate_inode_pages(mapping, 0);
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}
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EXPORT_SYMBOL(kill_bdev);
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/* Invalidate clean unused buffers and pagecache. */
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void invalidate_bdev(struct block_device *bdev)
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{
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struct address_space *mapping = bdev->bd_inode->i_mapping;
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if (mapping->nrpages == 0)
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return;
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invalidate_bh_lrus();
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lru_add_drain_all(); /* make sure all lru add caches are flushed */
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invalidate_mapping_pages(mapping, 0, -1);
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/* 99% of the time, we don't need to flush the cleancache on the bdev.
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* But, for the strange corners, lets be cautious
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*/
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cleancache_invalidate_inode(mapping);
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}
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EXPORT_SYMBOL(invalidate_bdev);
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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 || !is_power_of_2(size))
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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_logical_block_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_logical_block_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(rw, iocb, inode, I_BDEV(inode), iov, offset,
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nr_segs, blkdev_get_blocks, NULL, NULL, 0);
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}
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int __sync_blockdev(struct block_device *bdev, int wait)
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{
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if (!bdev)
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return 0;
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if (!wait)
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return filemap_flush(bdev->bd_inode->i_mapping);
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return filemap_write_and_wait(bdev->bd_inode->i_mapping);
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}
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/*
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* Write out and wait upon all the dirty data associated with a block
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* device via its mapping. Does not take the superblock lock.
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*/
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int sync_blockdev(struct block_device *bdev)
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{
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return __sync_blockdev(bdev, 1);
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}
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EXPORT_SYMBOL(sync_blockdev);
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/*
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* Write out and wait upon all dirty data associated with this
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* device. Filesystem data as well as the underlying block
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* device. Takes the superblock lock.
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*/
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int fsync_bdev(struct block_device *bdev)
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{
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struct super_block *sb = get_super(bdev);
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if (sb) {
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int res = sync_filesystem(sb);
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drop_super(sb);
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return res;
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}
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return sync_blockdev(bdev);
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}
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EXPORT_SYMBOL(fsync_bdev);
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/**
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* freeze_bdev -- lock a filesystem and force it into a consistent state
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* @bdev: blockdevice to lock
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*
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* If a superblock is found on this device, we take the s_umount semaphore
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* on it to make sure nobody unmounts until the snapshot creation is done.
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* The reference counter (bd_fsfreeze_count) guarantees that only the last
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* unfreeze process can unfreeze the frozen filesystem actually when multiple
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* freeze requests arrive simultaneously. It counts up in freeze_bdev() and
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* count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
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* actually.
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*/
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struct super_block *freeze_bdev(struct block_device *bdev)
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{
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struct super_block *sb;
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int error = 0;
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mutex_lock(&bdev->bd_fsfreeze_mutex);
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if (++bdev->bd_fsfreeze_count > 1) {
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/*
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* We don't even need to grab a reference - the first call
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* to freeze_bdev grab an active reference and only the last
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* thaw_bdev drops it.
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*/
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sb = get_super(bdev);
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drop_super(sb);
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return sb;
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}
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sb = get_active_super(bdev);
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if (!sb)
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goto out;
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error = freeze_super(sb);
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if (error) {
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deactivate_super(sb);
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bdev->bd_fsfreeze_count--;
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return ERR_PTR(error);
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}
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deactivate_super(sb);
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out:
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sync_blockdev(bdev);
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return sb; /* thaw_bdev releases s->s_umount */
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}
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EXPORT_SYMBOL(freeze_bdev);
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/**
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* thaw_bdev -- unlock filesystem
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* @bdev: blockdevice to unlock
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* @sb: associated superblock
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*
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* Unlocks the filesystem and marks it writeable again after freeze_bdev().
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*/
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int thaw_bdev(struct block_device *bdev, struct super_block *sb)
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{
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int error = -EINVAL;
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mutex_lock(&bdev->bd_fsfreeze_mutex);
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if (!bdev->bd_fsfreeze_count)
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goto out;
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error = 0;
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if (--bdev->bd_fsfreeze_count > 0)
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goto out;
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if (!sb)
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goto out;
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error = thaw_super(sb);
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if (error) {
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bdev->bd_fsfreeze_count++;
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return error;
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}
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out:
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return 0;
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}
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EXPORT_SYMBOL(thaw_bdev);
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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_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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return block_write_begin(mapping, pos, len, flags, pagep,
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blkdev_get_block);
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}
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static int blkdev_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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int ret;
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ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
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unlock_page(page);
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page_cache_release(page);
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return ret;
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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_path.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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retval = -EINVAL;
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switch (origin) {
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case SEEK_END:
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offset += size;
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break;
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case SEEK_CUR:
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offset += file->f_pos;
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case SEEK_SET:
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break;
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default:
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goto out;
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}
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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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out:
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mutex_unlock(&bd_inode->i_mutex);
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return retval;
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}
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int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
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{
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struct inode *bd_inode = filp->f_mapping->host;
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struct block_device *bdev = I_BDEV(bd_inode);
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int error;
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error = filemap_write_and_wait_range(filp->f_mapping, start, end);
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if (error)
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return error;
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|
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/*
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* There is no need to serialise calls to blkdev_issue_flush with
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* i_mutex and doing so causes performance issues with concurrent
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* O_SYNC writers to a block device.
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*/
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error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL);
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if (error == -EOPNOTSUPP)
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error = 0;
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return error;
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}
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EXPORT_SYMBOL(blkdev_fsync);
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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 struct kmem_cache * bdev_cachep __read_mostly;
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|
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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, GFP_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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|
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static void bdev_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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struct bdev_inode *bdi = BDEV_I(inode);
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|
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kmem_cache_free(bdev_cachep, bdi);
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}
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|
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static void bdev_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, bdev_i_callback);
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}
|
|
|
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static void init_once(void *foo)
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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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memset(bdev, 0, sizeof(*bdev));
|
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mutex_init(&bdev->bd_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_disks);
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#endif
|
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inode_init_once(&ei->vfs_inode);
|
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/* Initialize mutex for freeze. */
|
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mutex_init(&bdev->bd_fsfreeze_mutex);
|
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}
|
|
|
|
static inline void __bd_forget(struct inode *inode)
|
|
{
|
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list_del_init(&inode->i_devices);
|
|
inode->i_bdev = NULL;
|
|
inode->i_mapping = &inode->i_data;
|
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}
|
|
|
|
static void bdev_evict_inode(struct inode *inode)
|
|
{
|
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struct block_device *bdev = &BDEV_I(inode)->bdev;
|
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struct list_head *p;
|
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truncate_inode_pages(&inode->i_data, 0);
|
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invalidate_inode_buffers(inode); /* is it needed here? */
|
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end_writeback(inode);
|
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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 const struct super_operations bdev_sops = {
|
|
.statfs = simple_statfs,
|
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.alloc_inode = bdev_alloc_inode,
|
|
.destroy_inode = bdev_destroy_inode,
|
|
.drop_inode = generic_delete_inode,
|
|
.evict_inode = bdev_evict_inode,
|
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};
|
|
|
|
static struct dentry *bd_mount(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC);
|
|
}
|
|
|
|
static struct file_system_type bd_type = {
|
|
.name = "bdev",
|
|
.mount = bd_mount,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
|
|
static struct super_block *blockdev_superblock __read_mostly;
|
|
|
|
void __init bdev_cache_init(void)
|
|
{
|
|
int err;
|
|
static struct vfsmount *bd_mnt;
|
|
|
|
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);
|
|
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(blockdev_superblock, 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_super = 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);
|
|
|
|
/**
|
|
* bdgrab -- Grab a reference to an already referenced block device
|
|
* @bdev: Block device to grab a reference to.
|
|
*/
|
|
struct block_device *bdgrab(struct block_device *bdev)
|
|
{
|
|
ihold(bdev->bd_inode);
|
|
return bdev;
|
|
}
|
|
|
|
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) {
|
|
ihold(bdev->bd_inode);
|
|
spin_unlock(&bdev_lock);
|
|
return bdev;
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
|
|
bdev = bdget(inode->i_rdev);
|
|
if (bdev) {
|
|
spin_lock(&bdev_lock);
|
|
if (!inode->i_bdev) {
|
|
/*
|
|
* We take an additional reference to bd_inode,
|
|
* and it's released in clear_inode() of inode.
|
|
* So, we can access it via ->i_mapping always
|
|
* without igrab().
|
|
*/
|
|
ihold(bdev->bd_inode);
|
|
inode->i_bdev = bdev;
|
|
inode->i_mapping = bdev->bd_inode->i_mapping;
|
|
list_add(&inode->i_devices, &bdev->bd_inodes);
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
}
|
|
return bdev;
|
|
}
|
|
|
|
static inline int sb_is_blkdev_sb(struct super_block *sb)
|
|
{
|
|
return sb == blockdev_superblock;
|
|
}
|
|
|
|
/* 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 (!sb_is_blkdev_sb(inode->i_sb))
|
|
bdev = inode->i_bdev;
|
|
__bd_forget(inode);
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
|
|
if (bdev)
|
|
iput(bdev->bd_inode);
|
|
}
|
|
|
|
/**
|
|
* bd_may_claim - test whether a block device can be claimed
|
|
* @bdev: block device of interest
|
|
* @whole: whole block device containing @bdev, may equal @bdev
|
|
* @holder: holder trying to claim @bdev
|
|
*
|
|
* Test whether @bdev can be claimed by @holder.
|
|
*
|
|
* CONTEXT:
|
|
* spin_lock(&bdev_lock).
|
|
*
|
|
* RETURNS:
|
|
* %true if @bdev can be claimed, %false otherwise.
|
|
*/
|
|
static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
|
|
void *holder)
|
|
{
|
|
if (bdev->bd_holder == holder)
|
|
return true; /* already a holder */
|
|
else if (bdev->bd_holder != NULL)
|
|
return false; /* held by someone else */
|
|
else if (bdev->bd_contains == bdev)
|
|
return true; /* is a whole device which isn't held */
|
|
|
|
else if (whole->bd_holder == bd_may_claim)
|
|
return true; /* is a partition of a device that is being partitioned */
|
|
else if (whole->bd_holder != NULL)
|
|
return false; /* is a partition of a held device */
|
|
else
|
|
return true; /* is a partition of an un-held device */
|
|
}
|
|
|
|
/**
|
|
* bd_prepare_to_claim - prepare to claim a block device
|
|
* @bdev: block device of interest
|
|
* @whole: the whole device containing @bdev, may equal @bdev
|
|
* @holder: holder trying to claim @bdev
|
|
*
|
|
* Prepare to claim @bdev. This function fails if @bdev is already
|
|
* claimed by another holder and waits if another claiming is in
|
|
* progress. This function doesn't actually claim. On successful
|
|
* return, the caller has ownership of bd_claiming and bd_holder[s].
|
|
*
|
|
* CONTEXT:
|
|
* spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
|
|
* it multiple times.
|
|
*
|
|
* RETURNS:
|
|
* 0 if @bdev can be claimed, -EBUSY otherwise.
|
|
*/
|
|
static int bd_prepare_to_claim(struct block_device *bdev,
|
|
struct block_device *whole, void *holder)
|
|
{
|
|
retry:
|
|
/* if someone else claimed, fail */
|
|
if (!bd_may_claim(bdev, whole, holder))
|
|
return -EBUSY;
|
|
|
|
/* if claiming is already in progress, wait for it to finish */
|
|
if (whole->bd_claiming) {
|
|
wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
|
|
DEFINE_WAIT(wait);
|
|
|
|
prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
|
|
spin_unlock(&bdev_lock);
|
|
schedule();
|
|
finish_wait(wq, &wait);
|
|
spin_lock(&bdev_lock);
|
|
goto retry;
|
|
}
|
|
|
|
/* yay, all mine */
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bd_start_claiming - start claiming a block device
|
|
* @bdev: block device of interest
|
|
* @holder: holder trying to claim @bdev
|
|
*
|
|
* @bdev is about to be opened exclusively. Check @bdev can be opened
|
|
* exclusively and mark that an exclusive open is in progress. Each
|
|
* successful call to this function must be matched with a call to
|
|
* either bd_finish_claiming() or bd_abort_claiming() (which do not
|
|
* fail).
|
|
*
|
|
* This function is used to gain exclusive access to the block device
|
|
* without actually causing other exclusive open attempts to fail. It
|
|
* should be used when the open sequence itself requires exclusive
|
|
* access but may subsequently fail.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to the block device containing @bdev on success, ERR_PTR()
|
|
* value on failure.
|
|
*/
|
|
static struct block_device *bd_start_claiming(struct block_device *bdev,
|
|
void *holder)
|
|
{
|
|
struct gendisk *disk;
|
|
struct block_device *whole;
|
|
int partno, err;
|
|
|
|
might_sleep();
|
|
|
|
/*
|
|
* @bdev might not have been initialized properly yet, look up
|
|
* and grab the outer block device the hard way.
|
|
*/
|
|
disk = get_gendisk(bdev->bd_dev, &partno);
|
|
if (!disk)
|
|
return ERR_PTR(-ENXIO);
|
|
|
|
/*
|
|
* Normally, @bdev should equal what's returned from bdget_disk()
|
|
* if partno is 0; however, some drivers (floppy) use multiple
|
|
* bdev's for the same physical device and @bdev may be one of the
|
|
* aliases. Keep @bdev if partno is 0. This means claimer
|
|
* tracking is broken for those devices but it has always been that
|
|
* way.
|
|
*/
|
|
if (partno)
|
|
whole = bdget_disk(disk, 0);
|
|
else
|
|
whole = bdgrab(bdev);
|
|
|
|
module_put(disk->fops->owner);
|
|
put_disk(disk);
|
|
if (!whole)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/* prepare to claim, if successful, mark claiming in progress */
|
|
spin_lock(&bdev_lock);
|
|
|
|
err = bd_prepare_to_claim(bdev, whole, holder);
|
|
if (err == 0) {
|
|
whole->bd_claiming = holder;
|
|
spin_unlock(&bdev_lock);
|
|
return whole;
|
|
} else {
|
|
spin_unlock(&bdev_lock);
|
|
bdput(whole);
|
|
return ERR_PTR(err);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
struct bd_holder_disk {
|
|
struct list_head list;
|
|
struct gendisk *disk;
|
|
int refcnt;
|
|
};
|
|
|
|
static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
|
|
struct gendisk *disk)
|
|
{
|
|
struct bd_holder_disk *holder;
|
|
|
|
list_for_each_entry(holder, &bdev->bd_holder_disks, list)
|
|
if (holder->disk == disk)
|
|
return holder;
|
|
return NULL;
|
|
}
|
|
|
|
static int add_symlink(struct kobject *from, struct kobject *to)
|
|
{
|
|
return sysfs_create_link(from, to, kobject_name(to));
|
|
}
|
|
|
|
static void del_symlink(struct kobject *from, struct kobject *to)
|
|
{
|
|
sysfs_remove_link(from, kobject_name(to));
|
|
}
|
|
|
|
/**
|
|
* bd_link_disk_holder - create symlinks between holding disk and slave bdev
|
|
* @bdev: the claimed slave bdev
|
|
* @disk: the holding disk
|
|
*
|
|
* DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
|
|
*
|
|
* This functions creates the following sysfs symlinks.
|
|
*
|
|
* - from "slaves" directory of the holder @disk to the claimed @bdev
|
|
* - from "holders" directory of the @bdev to the holder @disk
|
|
*
|
|
* For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
|
|
* passed to bd_link_disk_holder(), then:
|
|
*
|
|
* /sys/block/dm-0/slaves/sda --> /sys/block/sda
|
|
* /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
|
|
*
|
|
* The caller must have claimed @bdev before calling this function and
|
|
* ensure that both @bdev and @disk are valid during the creation and
|
|
* lifetime of these symlinks.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
|
|
{
|
|
struct bd_holder_disk *holder;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
|
|
WARN_ON_ONCE(!bdev->bd_holder);
|
|
|
|
/* FIXME: remove the following once add_disk() handles errors */
|
|
if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
|
|
goto out_unlock;
|
|
|
|
holder = bd_find_holder_disk(bdev, disk);
|
|
if (holder) {
|
|
holder->refcnt++;
|
|
goto out_unlock;
|
|
}
|
|
|
|
holder = kzalloc(sizeof(*holder), GFP_KERNEL);
|
|
if (!holder) {
|
|
ret = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&holder->list);
|
|
holder->disk = disk;
|
|
holder->refcnt = 1;
|
|
|
|
ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
|
|
if (ret)
|
|
goto out_free;
|
|
|
|
ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
|
|
if (ret)
|
|
goto out_del;
|
|
/*
|
|
* bdev could be deleted beneath us which would implicitly destroy
|
|
* the holder directory. Hold on to it.
|
|
*/
|
|
kobject_get(bdev->bd_part->holder_dir);
|
|
|
|
list_add(&holder->list, &bdev->bd_holder_disks);
|
|
goto out_unlock;
|
|
|
|
out_del:
|
|
del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
|
|
out_free:
|
|
kfree(holder);
|
|
out_unlock:
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_link_disk_holder);
|
|
|
|
/**
|
|
* bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
|
|
* @bdev: the calimed slave bdev
|
|
* @disk: the holding disk
|
|
*
|
|
* DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*/
|
|
void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
|
|
{
|
|
struct bd_holder_disk *holder;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
|
|
holder = bd_find_holder_disk(bdev, disk);
|
|
|
|
if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
|
|
del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
|
|
del_symlink(bdev->bd_part->holder_dir,
|
|
&disk_to_dev(disk)->kobj);
|
|
kobject_put(bdev->bd_part->holder_dir);
|
|
list_del_init(&holder->list);
|
|
kfree(holder);
|
|
}
|
|
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
|
|
#endif
|
|
|
|
/**
|
|
* flush_disk - invalidates all buffer-cache entries on a disk
|
|
*
|
|
* @bdev: struct block device to be flushed
|
|
* @kill_dirty: flag to guide handling of dirty inodes
|
|
*
|
|
* Invalidates all buffer-cache entries on a disk. It should be called
|
|
* when a disk has been changed -- either by a media change or online
|
|
* resize.
|
|
*/
|
|
static void flush_disk(struct block_device *bdev, bool kill_dirty)
|
|
{
|
|
if (__invalidate_device(bdev, kill_dirty)) {
|
|
char name[BDEVNAME_SIZE] = "";
|
|
|
|
if (bdev->bd_disk)
|
|
disk_name(bdev->bd_disk, 0, name);
|
|
printk(KERN_WARNING "VFS: busy inodes on changed media or "
|
|
"resized disk %s\n", name);
|
|
}
|
|
|
|
if (!bdev->bd_disk)
|
|
return;
|
|
if (disk_part_scan_enabled(bdev->bd_disk))
|
|
bdev->bd_invalidated = 1;
|
|
}
|
|
|
|
/**
|
|
* check_disk_size_change - checks for disk size change and adjusts bdev size.
|
|
* @disk: struct gendisk to check
|
|
* @bdev: struct bdev to adjust.
|
|
*
|
|
* This routine checks to see if the bdev size does not match the disk size
|
|
* and adjusts it if it differs.
|
|
*/
|
|
void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
|
|
{
|
|
loff_t disk_size, bdev_size;
|
|
|
|
disk_size = (loff_t)get_capacity(disk) << 9;
|
|
bdev_size = i_size_read(bdev->bd_inode);
|
|
if (disk_size != bdev_size) {
|
|
char name[BDEVNAME_SIZE];
|
|
|
|
disk_name(disk, 0, name);
|
|
printk(KERN_INFO
|
|
"%s: detected capacity change from %lld to %lld\n",
|
|
name, bdev_size, disk_size);
|
|
i_size_write(bdev->bd_inode, disk_size);
|
|
flush_disk(bdev, false);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(check_disk_size_change);
|
|
|
|
/**
|
|
* revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
|
|
* @disk: struct gendisk to be revalidated
|
|
*
|
|
* This routine is a wrapper for lower-level driver's revalidate_disk
|
|
* call-backs. It is used to do common pre and post operations needed
|
|
* for all revalidate_disk operations.
|
|
*/
|
|
int revalidate_disk(struct gendisk *disk)
|
|
{
|
|
struct block_device *bdev;
|
|
int ret = 0;
|
|
|
|
if (disk->fops->revalidate_disk)
|
|
ret = disk->fops->revalidate_disk(disk);
|
|
|
|
bdev = bdget_disk(disk, 0);
|
|
if (!bdev)
|
|
return ret;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
check_disk_size_change(disk, bdev);
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(bdev);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(revalidate_disk);
|
|
|
|
/*
|
|
* 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;
|
|
const struct block_device_operations *bdops = disk->fops;
|
|
unsigned int events;
|
|
|
|
events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
|
|
DISK_EVENT_EJECT_REQUEST);
|
|
if (!(events & DISK_EVENT_MEDIA_CHANGE))
|
|
return 0;
|
|
|
|
flush_disk(bdev, true);
|
|
if (bdops->revalidate_disk)
|
|
bdops->revalidate_disk(bdev->bd_disk);
|
|
return 1;
|
|
}
|
|
|
|
EXPORT_SYMBOL(check_disk_change);
|
|
|
|
void bd_set_size(struct block_device *bdev, loff_t size)
|
|
{
|
|
unsigned bsize = bdev_logical_block_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_put(struct block_device *bdev, fmode_t mode, int for_part);
|
|
|
|
/*
|
|
* bd_mutex locking:
|
|
*
|
|
* mutex_lock(part->bd_mutex)
|
|
* mutex_lock_nested(whole->bd_mutex, 1)
|
|
*/
|
|
|
|
static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
|
|
{
|
|
struct gendisk *disk;
|
|
struct module *owner;
|
|
int ret;
|
|
int partno;
|
|
int perm = 0;
|
|
|
|
if (mode & FMODE_READ)
|
|
perm |= MAY_READ;
|
|
if (mode & FMODE_WRITE)
|
|
perm |= MAY_WRITE;
|
|
/*
|
|
* hooks: /n/, see "layering violations".
|
|
*/
|
|
if (!for_part) {
|
|
ret = devcgroup_inode_permission(bdev->bd_inode, perm);
|
|
if (ret != 0) {
|
|
bdput(bdev);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
restart:
|
|
|
|
ret = -ENXIO;
|
|
disk = get_gendisk(bdev->bd_dev, &partno);
|
|
if (!disk)
|
|
goto out;
|
|
owner = disk->fops->owner;
|
|
|
|
disk_block_events(disk);
|
|
mutex_lock_nested(&bdev->bd_mutex, for_part);
|
|
if (!bdev->bd_openers) {
|
|
bdev->bd_disk = disk;
|
|
bdev->bd_queue = disk->queue;
|
|
bdev->bd_contains = bdev;
|
|
if (!partno) {
|
|
struct backing_dev_info *bdi;
|
|
|
|
ret = -ENXIO;
|
|
bdev->bd_part = disk_get_part(disk, partno);
|
|
if (!bdev->bd_part)
|
|
goto out_clear;
|
|
|
|
ret = 0;
|
|
if (disk->fops->open) {
|
|
ret = disk->fops->open(bdev, mode);
|
|
if (ret == -ERESTARTSYS) {
|
|
/* Lost a race with 'disk' being
|
|
* deleted, try again.
|
|
* See md.c
|
|
*/
|
|
disk_put_part(bdev->bd_part);
|
|
bdev->bd_part = NULL;
|
|
bdev->bd_disk = NULL;
|
|
bdev->bd_queue = NULL;
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
disk_unblock_events(disk);
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
goto restart;
|
|
}
|
|
}
|
|
|
|
if (!ret && !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_inode_switch_bdi(bdev->bd_inode, bdi);
|
|
}
|
|
|
|
/*
|
|
* If the device is invalidated, rescan partition
|
|
* if open succeeded or failed with -ENOMEDIUM.
|
|
* The latter is necessary to prevent ghost
|
|
* partitions on a removed medium.
|
|
*/
|
|
if (bdev->bd_invalidated) {
|
|
if (!ret)
|
|
rescan_partitions(disk, bdev);
|
|
else if (ret == -ENOMEDIUM)
|
|
invalidate_partitions(disk, bdev);
|
|
}
|
|
if (ret)
|
|
goto out_clear;
|
|
} else {
|
|
struct block_device *whole;
|
|
whole = bdget_disk(disk, 0);
|
|
ret = -ENOMEM;
|
|
if (!whole)
|
|
goto out_clear;
|
|
BUG_ON(for_part);
|
|
ret = __blkdev_get(whole, mode, 1);
|
|
if (ret)
|
|
goto out_clear;
|
|
bdev->bd_contains = whole;
|
|
bdev_inode_switch_bdi(bdev->bd_inode,
|
|
whole->bd_inode->i_data.backing_dev_info);
|
|
bdev->bd_part = disk_get_part(disk, partno);
|
|
if (!(disk->flags & GENHD_FL_UP) ||
|
|
!bdev->bd_part || !bdev->bd_part->nr_sects) {
|
|
ret = -ENXIO;
|
|
goto out_clear;
|
|
}
|
|
bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
|
|
}
|
|
} else {
|
|
if (bdev->bd_contains == bdev) {
|
|
ret = 0;
|
|
if (bdev->bd_disk->fops->open)
|
|
ret = bdev->bd_disk->fops->open(bdev, mode);
|
|
/* the same as first opener case, read comment there */
|
|
if (bdev->bd_invalidated) {
|
|
if (!ret)
|
|
rescan_partitions(bdev->bd_disk, bdev);
|
|
else if (ret == -ENOMEDIUM)
|
|
invalidate_partitions(bdev->bd_disk, bdev);
|
|
}
|
|
if (ret)
|
|
goto out_unlock_bdev;
|
|
}
|
|
/* only one opener holds refs to the module and disk */
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
}
|
|
bdev->bd_openers++;
|
|
if (for_part)
|
|
bdev->bd_part_count++;
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
disk_unblock_events(disk);
|
|
return 0;
|
|
|
|
out_clear:
|
|
disk_put_part(bdev->bd_part);
|
|
bdev->bd_disk = NULL;
|
|
bdev->bd_part = NULL;
|
|
bdev->bd_queue = NULL;
|
|
bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
|
|
if (bdev != bdev->bd_contains)
|
|
__blkdev_put(bdev->bd_contains, mode, 1);
|
|
bdev->bd_contains = NULL;
|
|
out_unlock_bdev:
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
disk_unblock_events(disk);
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
out:
|
|
bdput(bdev);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* blkdev_get - open a block device
|
|
* @bdev: block_device to open
|
|
* @mode: FMODE_* mask
|
|
* @holder: exclusive holder identifier
|
|
*
|
|
* Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
|
|
* open with exclusive access. Specifying %FMODE_EXCL with %NULL
|
|
* @holder is invalid. Exclusive opens may nest for the same @holder.
|
|
*
|
|
* On success, the reference count of @bdev is unchanged. On failure,
|
|
* @bdev is put.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
|
|
{
|
|
struct block_device *whole = NULL;
|
|
int res;
|
|
|
|
WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
|
|
|
|
if ((mode & FMODE_EXCL) && holder) {
|
|
whole = bd_start_claiming(bdev, holder);
|
|
if (IS_ERR(whole)) {
|
|
bdput(bdev);
|
|
return PTR_ERR(whole);
|
|
}
|
|
}
|
|
|
|
res = __blkdev_get(bdev, mode, 0);
|
|
|
|
if (whole) {
|
|
struct gendisk *disk = whole->bd_disk;
|
|
|
|
/* finish claiming */
|
|
mutex_lock(&bdev->bd_mutex);
|
|
spin_lock(&bdev_lock);
|
|
|
|
if (!res) {
|
|
BUG_ON(!bd_may_claim(bdev, whole, holder));
|
|
/*
|
|
* Note that for a whole device bd_holders
|
|
* will be incremented twice, and bd_holder
|
|
* will be set to bd_may_claim before being
|
|
* set to holder
|
|
*/
|
|
whole->bd_holders++;
|
|
whole->bd_holder = bd_may_claim;
|
|
bdev->bd_holders++;
|
|
bdev->bd_holder = holder;
|
|
}
|
|
|
|
/* tell others that we're done */
|
|
BUG_ON(whole->bd_claiming != holder);
|
|
whole->bd_claiming = NULL;
|
|
wake_up_bit(&whole->bd_claiming, 0);
|
|
|
|
spin_unlock(&bdev_lock);
|
|
|
|
/*
|
|
* Block event polling for write claims if requested. Any
|
|
* write holder makes the write_holder state stick until
|
|
* all are released. This is good enough and tracking
|
|
* individual writeable reference is too fragile given the
|
|
* way @mode is used in blkdev_get/put().
|
|
*/
|
|
if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
|
|
(disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
|
|
bdev->bd_write_holder = true;
|
|
disk_block_events(disk);
|
|
}
|
|
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(whole);
|
|
}
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get);
|
|
|
|
/**
|
|
* blkdev_get_by_path - open a block device by name
|
|
* @path: path to the block device to open
|
|
* @mode: FMODE_* mask
|
|
* @holder: exclusive holder identifier
|
|
*
|
|
* Open the blockdevice described by the device file at @path. @mode
|
|
* and @holder are identical to blkdev_get().
|
|
*
|
|
* On success, the returned block_device has reference count of one.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to block_device on success, ERR_PTR(-errno) on failure.
|
|
*/
|
|
struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
|
|
void *holder)
|
|
{
|
|
struct block_device *bdev;
|
|
int err;
|
|
|
|
bdev = lookup_bdev(path);
|
|
if (IS_ERR(bdev))
|
|
return bdev;
|
|
|
|
err = blkdev_get(bdev, mode, holder);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
|
|
blkdev_put(bdev, mode);
|
|
return ERR_PTR(-EACCES);
|
|
}
|
|
|
|
return bdev;
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get_by_path);
|
|
|
|
/**
|
|
* blkdev_get_by_dev - open a block device by device number
|
|
* @dev: device number of block device to open
|
|
* @mode: FMODE_* mask
|
|
* @holder: exclusive holder identifier
|
|
*
|
|
* Open the blockdevice described by device number @dev. @mode and
|
|
* @holder are identical to blkdev_get().
|
|
*
|
|
* 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.
|
|
*
|
|
* On success, the returned block_device has reference count of one.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to block_device on success, ERR_PTR(-errno) on failure.
|
|
*/
|
|
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
|
|
{
|
|
struct block_device *bdev;
|
|
int err;
|
|
|
|
bdev = bdget(dev);
|
|
if (!bdev)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
err = blkdev_get(bdev, mode, holder);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
return bdev;
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get_by_dev);
|
|
|
|
static int blkdev_open(struct inode * inode, struct file * filp)
|
|
{
|
|
struct block_device *bdev;
|
|
|
|
/*
|
|
* 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;
|
|
|
|
if (filp->f_flags & O_NDELAY)
|
|
filp->f_mode |= FMODE_NDELAY;
|
|
if (filp->f_flags & O_EXCL)
|
|
filp->f_mode |= FMODE_EXCL;
|
|
if ((filp->f_flags & O_ACCMODE) == 3)
|
|
filp->f_mode |= FMODE_WRITE_IOCTL;
|
|
|
|
bdev = bd_acquire(inode);
|
|
if (bdev == NULL)
|
|
return -ENOMEM;
|
|
|
|
filp->f_mapping = bdev->bd_inode->i_mapping;
|
|
|
|
return blkdev_get(bdev, filp->f_mode, filp);
|
|
}
|
|
|
|
static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
|
|
{
|
|
int ret = 0;
|
|
struct gendisk *disk = bdev->bd_disk;
|
|
struct block_device *victim = NULL;
|
|
|
|
mutex_lock_nested(&bdev->bd_mutex, for_part);
|
|
if (for_part)
|
|
bdev->bd_part_count--;
|
|
|
|
if (!--bdev->bd_openers) {
|
|
WARN_ON_ONCE(bdev->bd_holders);
|
|
sync_blockdev(bdev);
|
|
kill_bdev(bdev);
|
|
/* ->release can cause the old bdi to disappear,
|
|
* so must switch it out first
|
|
*/
|
|
bdev_inode_switch_bdi(bdev->bd_inode,
|
|
&default_backing_dev_info);
|
|
}
|
|
if (bdev->bd_contains == bdev) {
|
|
if (disk->fops->release)
|
|
ret = disk->fops->release(disk, mode);
|
|
}
|
|
if (!bdev->bd_openers) {
|
|
struct module *owner = disk->fops->owner;
|
|
|
|
disk_put_part(bdev->bd_part);
|
|
bdev->bd_part = NULL;
|
|
bdev->bd_disk = NULL;
|
|
if (bdev != bdev->bd_contains)
|
|
victim = bdev->bd_contains;
|
|
bdev->bd_contains = NULL;
|
|
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
}
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(bdev);
|
|
if (victim)
|
|
__blkdev_put(victim, mode, 1);
|
|
return ret;
|
|
}
|
|
|
|
int blkdev_put(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
mutex_lock(&bdev->bd_mutex);
|
|
|
|
if (mode & FMODE_EXCL) {
|
|
bool bdev_free;
|
|
|
|
/*
|
|
* Release a claim on the device. The holder fields
|
|
* are protected with bdev_lock. bd_mutex is to
|
|
* synchronize disk_holder unlinking.
|
|
*/
|
|
spin_lock(&bdev_lock);
|
|
|
|
WARN_ON_ONCE(--bdev->bd_holders < 0);
|
|
WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
|
|
|
|
/* bd_contains might point to self, check in a separate step */
|
|
if ((bdev_free = !bdev->bd_holders))
|
|
bdev->bd_holder = NULL;
|
|
if (!bdev->bd_contains->bd_holders)
|
|
bdev->bd_contains->bd_holder = NULL;
|
|
|
|
spin_unlock(&bdev_lock);
|
|
|
|
/*
|
|
* If this was the last claim, remove holder link and
|
|
* unblock evpoll if it was a write holder.
|
|
*/
|
|
if (bdev_free && bdev->bd_write_holder) {
|
|
disk_unblock_events(bdev->bd_disk);
|
|
bdev->bd_write_holder = false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Trigger event checking and tell drivers to flush MEDIA_CHANGE
|
|
* event. This is to ensure detection of media removal commanded
|
|
* from userland - e.g. eject(1).
|
|
*/
|
|
disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
|
|
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
|
|
return __blkdev_put(bdev, mode, 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);
|
|
|
|
return blkdev_put(bdev, filp->f_mode);
|
|
}
|
|
|
|
static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
|
|
{
|
|
struct block_device *bdev = I_BDEV(file->f_mapping->host);
|
|
fmode_t mode = file->f_mode;
|
|
|
|
/*
|
|
* O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
|
|
* to updated it before every ioctl.
|
|
*/
|
|
if (file->f_flags & O_NDELAY)
|
|
mode |= FMODE_NDELAY;
|
|
else
|
|
mode &= ~FMODE_NDELAY;
|
|
|
|
return blkdev_ioctl(bdev, mode, cmd, arg);
|
|
}
|
|
|
|
/*
|
|
* Write data to the block device. Only intended for the block device itself
|
|
* and the raw driver which basically is a fake block device.
|
|
*
|
|
* Does not take i_mutex for the write and thus is not for general purpose
|
|
* use.
|
|
*/
|
|
ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
ssize_t ret;
|
|
|
|
BUG_ON(iocb->ki_pos != pos);
|
|
|
|
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
|
|
if (ret > 0 || ret == -EIOCBQUEUED) {
|
|
ssize_t err;
|
|
|
|
err = generic_write_sync(file, pos, ret);
|
|
if (err < 0 && ret > 0)
|
|
ret = err;
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkdev_aio_write);
|
|
|
|
/*
|
|
* Try to release a page associated with block device when the system
|
|
* is under memory pressure.
|
|
*/
|
|
static int blkdev_releasepage(struct page *page, gfp_t wait)
|
|
{
|
|
struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
|
|
|
|
if (super && super->s_op->bdev_try_to_free_page)
|
|
return super->s_op->bdev_try_to_free_page(super, page, wait);
|
|
|
|
return try_to_free_buffers(page);
|
|
}
|
|
|
|
static const struct address_space_operations def_blk_aops = {
|
|
.readpage = blkdev_readpage,
|
|
.writepage = blkdev_writepage,
|
|
.write_begin = blkdev_write_begin,
|
|
.write_end = blkdev_write_end,
|
|
.writepages = generic_writepages,
|
|
.releasepage = blkdev_releasepage,
|
|
.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 = blkdev_aio_write,
|
|
.mmap = generic_file_mmap,
|
|
.fsync = blkdev_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, 0, cmd, arg);
|
|
set_fs(old_fs);
|
|
return res;
|
|
}
|
|
|
|
EXPORT_SYMBOL(ioctl_by_bdev);
|
|
|
|
/**
|
|
* lookup_bdev - lookup a struct block_device by name
|
|
* @pathname: special file representing the block device
|
|
*
|
|
* Get a reference to the blockdevice at @pathname in the current
|
|
* namespace if possible and return it. Return ERR_PTR(error)
|
|
* otherwise.
|
|
*/
|
|
struct block_device *lookup_bdev(const char *pathname)
|
|
{
|
|
struct block_device *bdev;
|
|
struct inode *inode;
|
|
struct path path;
|
|
int error;
|
|
|
|
if (!pathname || !*pathname)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
error = kern_path(pathname, LOOKUP_FOLLOW, &path);
|
|
if (error)
|
|
return ERR_PTR(error);
|
|
|
|
inode = path.dentry->d_inode;
|
|
error = -ENOTBLK;
|
|
if (!S_ISBLK(inode->i_mode))
|
|
goto fail;
|
|
error = -EACCES;
|
|
if (path.mnt->mnt_flags & MNT_NODEV)
|
|
goto fail;
|
|
error = -ENOMEM;
|
|
bdev = bd_acquire(inode);
|
|
if (!bdev)
|
|
goto fail;
|
|
out:
|
|
path_put(&path);
|
|
return bdev;
|
|
fail:
|
|
bdev = ERR_PTR(error);
|
|
goto out;
|
|
}
|
|
EXPORT_SYMBOL(lookup_bdev);
|
|
|
|
int __invalidate_device(struct block_device *bdev, bool kill_dirty)
|
|
{
|
|
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, kill_dirty);
|
|
drop_super(sb);
|
|
}
|
|
invalidate_bdev(bdev);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(__invalidate_device);
|