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1809 lines
44 KiB
1809 lines
44 KiB
/* |
|
* linux/fs/block_dev.c |
|
* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
|
* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
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*/ |
|
|
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#include <linux/init.h> |
|
#include <linux/mm.h> |
|
#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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|
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static const struct address_space_operations def_blk_aops; |
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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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|
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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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/* |
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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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sector_t blkdev_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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|
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if (mapping->nrpages == 0) |
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return; |
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|
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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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|
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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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|
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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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cleancache_invalidate_inode(mapping); |
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} |
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EXPORT_SYMBOL(invalidate_bdev); |
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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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struct address_space *mapping; |
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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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/* Prevent starting I/O or mapping the device */ |
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down_write(&bdev->bd_block_size_semaphore); |
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|
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/* Check that the block device is not memory mapped */ |
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mapping = bdev->bd_inode->i_mapping; |
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mutex_lock(&mapping->i_mmap_mutex); |
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if (!prio_tree_empty(&mapping->i_mmap) || |
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!list_empty(&mapping->i_mmap_nonlinear)) { |
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mutex_unlock(&mapping->i_mmap_mutex); |
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up_write(&bdev->bd_block_size_semaphore); |
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return -EBUSY; |
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} |
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mutex_unlock(&mapping->i_mmap_mutex); |
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|
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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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|
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up_write(&bdev->bd_block_size_semaphore); |
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|
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return 0; |
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} |
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|
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EXPORT_SYMBOL(set_blocksize); |
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|
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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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|
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EXPORT_SYMBOL(sb_set_blocksize); |
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|
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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 >= blkdev_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. |
|
* return a hole, they will have to call get_block again |
|
* 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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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 = blkdev_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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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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int __sync_blockdev(struct block_device *bdev, int wait) |
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{ |
|
if (!bdev) |
|
return 0; |
|
if (!wait) |
|
return filemap_flush(bdev->bd_inode->i_mapping); |
|
return filemap_write_and_wait(bdev->bd_inode->i_mapping); |
|
} |
|
|
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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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return __sync_blockdev(bdev, 1); |
|
} |
|
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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int fsync_bdev(struct block_device *bdev) |
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{ |
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struct super_block *sb = get_super(bdev); |
|
if (sb) { |
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int res = sync_filesystem(sb); |
|
drop_super(sb); |
|
return res; |
|
} |
|
return sync_blockdev(bdev); |
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} |
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EXPORT_SYMBOL(fsync_bdev); |
|
|
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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 |
|
* on it to make sure nobody unmounts until the snapshot creation is done. |
|
* 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 |
|
* 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 |
|
* to freeze_bdev grab an active reference and only the last |
|
* thaw_bdev drops it. |
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*/ |
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sb = get_super(bdev); |
|
drop_super(sb); |
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mutex_unlock(&bdev->bd_fsfreeze_mutex); |
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return sb; |
|
} |
|
|
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sb = get_active_super(bdev); |
|
if (!sb) |
|
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 |
|
* @bdev: blockdevice to unlock |
|
* @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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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) |
|
goto out; |
|
|
|
if (!sb) |
|
goto out; |
|
|
|
error = thaw_super(sb); |
|
if (error) { |
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bdev->bd_fsfreeze_count++; |
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mutex_unlock(&bdev->bd_fsfreeze_mutex); |
|
return error; |
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} |
|
out: |
|
mutex_unlock(&bdev->bd_fsfreeze_mutex); |
|
return 0; |
|
} |
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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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return block_write_full_page(page, blkdev_get_block, wbc); |
|
} |
|
|
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static int blkdev_readpage(struct file * file, struct page * page) |
|
{ |
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return block_read_full_page(page, blkdev_get_block); |
|
} |
|
|
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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, |
|
blkdev_get_block); |
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} |
|
|
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static int blkdev_write_end(struct file *file, struct address_space *mapping, |
|
loff_t pos, unsigned len, unsigned copied, |
|
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); |
|
|
|
unlock_page(page); |
|
page_cache_release(page); |
|
|
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return ret; |
|
} |
|
|
|
/* |
|
* private llseek: |
|
* for a block special file file->f_path.dentry->d_inode->i_size is zero |
|
* so we compute the size by hand (just as in block_read/write above) |
|
*/ |
|
static loff_t block_llseek(struct file *file, loff_t offset, int origin) |
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{ |
|
struct inode *bd_inode = file->f_mapping->host; |
|
loff_t size; |
|
loff_t retval; |
|
|
|
mutex_lock(&bd_inode->i_mutex); |
|
size = i_size_read(bd_inode); |
|
|
|
retval = -EINVAL; |
|
switch (origin) { |
|
case SEEK_END: |
|
offset += size; |
|
break; |
|
case SEEK_CUR: |
|
offset += file->f_pos; |
|
case SEEK_SET: |
|
break; |
|
default: |
|
goto out; |
|
} |
|
if (offset >= 0 && offset <= size) { |
|
if (offset != file->f_pos) { |
|
file->f_pos = offset; |
|
} |
|
retval = offset; |
|
} |
|
out: |
|
mutex_unlock(&bd_inode->i_mutex); |
|
return retval; |
|
} |
|
|
|
int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
|
{ |
|
struct inode *bd_inode = filp->f_mapping->host; |
|
struct block_device *bdev = I_BDEV(bd_inode); |
|
int error; |
|
|
|
error = filemap_write_and_wait_range(filp->f_mapping, start, end); |
|
if (error) |
|
return error; |
|
|
|
/* |
|
* There is no need to serialise calls to blkdev_issue_flush with |
|
* i_mutex and doing so causes performance issues with concurrent |
|
* O_SYNC writers to a block device. |
|
*/ |
|
error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
|
if (error == -EOPNOTSUPP) |
|
error = 0; |
|
|
|
return error; |
|
} |
|
EXPORT_SYMBOL(blkdev_fsync); |
|
|
|
/* |
|
* pseudo-fs |
|
*/ |
|
|
|
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
|
static struct kmem_cache * bdev_cachep __read_mostly; |
|
|
|
static struct inode *bdev_alloc_inode(struct super_block *sb) |
|
{ |
|
struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
|
if (!ei) |
|
return NULL; |
|
return &ei->vfs_inode; |
|
} |
|
|
|
static void bdev_i_callback(struct rcu_head *head) |
|
{ |
|
struct inode *inode = container_of(head, struct inode, i_rcu); |
|
struct bdev_inode *bdi = BDEV_I(inode); |
|
|
|
kmem_cache_free(bdev_cachep, bdi); |
|
} |
|
|
|
static void bdev_destroy_inode(struct inode *inode) |
|
{ |
|
call_rcu(&inode->i_rcu, bdev_i_callback); |
|
} |
|
|
|
static void init_once(void *foo) |
|
{ |
|
struct bdev_inode *ei = (struct bdev_inode *) foo; |
|
struct block_device *bdev = &ei->bdev; |
|
|
|
memset(bdev, 0, sizeof(*bdev)); |
|
mutex_init(&bdev->bd_mutex); |
|
INIT_LIST_HEAD(&bdev->bd_inodes); |
|
INIT_LIST_HEAD(&bdev->bd_list); |
|
#ifdef CONFIG_SYSFS |
|
INIT_LIST_HEAD(&bdev->bd_holder_disks); |
|
#endif |
|
inode_init_once(&ei->vfs_inode); |
|
/* Initialize mutex for freeze. */ |
|
mutex_init(&bdev->bd_fsfreeze_mutex); |
|
init_rwsem(&bdev->bd_block_size_semaphore); |
|
} |
|
|
|
static inline void __bd_forget(struct inode *inode) |
|
{ |
|
list_del_init(&inode->i_devices); |
|
inode->i_bdev = NULL; |
|
inode->i_mapping = &inode->i_data; |
|
} |
|
|
|
static void bdev_evict_inode(struct inode *inode) |
|
{ |
|
struct block_device *bdev = &BDEV_I(inode)->bdev; |
|
struct list_head *p; |
|
truncate_inode_pages(&inode->i_data, 0); |
|
invalidate_inode_buffers(inode); /* is it needed here? */ |
|
clear_inode(inode); |
|
spin_lock(&bdev_lock); |
|
while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { |
|
__bd_forget(list_entry(p, struct inode, i_devices)); |
|
} |
|
list_del_init(&bdev->bd_list); |
|
spin_unlock(&bdev_lock); |
|
} |
|
|
|
static const struct super_operations bdev_sops = { |
|
.statfs = simple_statfs, |
|
.alloc_inode = bdev_alloc_inode, |
|
.destroy_inode = bdev_destroy_inode, |
|
.drop_inode = generic_delete_inode, |
|
.evict_inode = bdev_evict_inode, |
|
}; |
|
|
|
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); |
|
} |
|
|
|
ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov, |
|
unsigned long nr_segs, loff_t pos) |
|
{ |
|
ssize_t ret; |
|
struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); |
|
|
|
down_read(&bdev->bd_block_size_semaphore); |
|
|
|
ret = generic_file_aio_read(iocb, iov, nr_segs, pos); |
|
|
|
up_read(&bdev->bd_block_size_semaphore); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(blkdev_aio_read); |
|
|
|
/* |
|
* 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; |
|
struct block_device *bdev = I_BDEV(file->f_mapping->host); |
|
struct blk_plug plug; |
|
ssize_t ret; |
|
|
|
BUG_ON(iocb->ki_pos != pos); |
|
|
|
blk_start_plug(&plug); |
|
|
|
down_read(&bdev->bd_block_size_semaphore); |
|
|
|
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; |
|
} |
|
|
|
up_read(&bdev->bd_block_size_semaphore); |
|
|
|
blk_finish_plug(&plug); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(blkdev_aio_write); |
|
|
|
int blkdev_mmap(struct file *file, struct vm_area_struct *vma) |
|
{ |
|
int ret; |
|
struct block_device *bdev = I_BDEV(file->f_mapping->host); |
|
|
|
down_read(&bdev->bd_block_size_semaphore); |
|
|
|
ret = generic_file_mmap(file, vma); |
|
|
|
up_read(&bdev->bd_block_size_semaphore); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* 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 = blkdev_aio_read, |
|
.aio_write = blkdev_aio_write, |
|
.mmap = blkdev_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); |
|
|
|
void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) |
|
{ |
|
struct inode *inode, *old_inode = NULL; |
|
|
|
spin_lock(&inode_sb_list_lock); |
|
list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { |
|
struct address_space *mapping = inode->i_mapping; |
|
|
|
spin_lock(&inode->i_lock); |
|
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || |
|
mapping->nrpages == 0) { |
|
spin_unlock(&inode->i_lock); |
|
continue; |
|
} |
|
__iget(inode); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(&inode_sb_list_lock); |
|
/* |
|
* We hold a reference to 'inode' so it couldn't have been |
|
* removed from s_inodes list while we dropped the |
|
* inode_sb_list_lock. We cannot iput the inode now as we can |
|
* be holding the last reference and we cannot iput it under |
|
* inode_sb_list_lock. So we keep the reference and iput it |
|
* later. |
|
*/ |
|
iput(old_inode); |
|
old_inode = inode; |
|
|
|
func(I_BDEV(inode), arg); |
|
|
|
spin_lock(&inode_sb_list_lock); |
|
} |
|
spin_unlock(&inode_sb_list_lock); |
|
iput(old_inode); |
|
}
|
|
|