![Jun'ichi Nomura](/assets/img/avatar_default.png)
Thanks Thomas and Christoph for testing and review. I removed 'smp_wmb()' before up_write from the previous patch, since up_write() should have necessary ordering constraints. (I.e. the change of s_frozen is visible to others after up_write) I'm quite sure the change is harmless but if you are uncomfortable with Tested-by/Reviewed-by on the modified patch, please remove them. If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of deactivate_locked_super(). Also, keep sb->s_frozen consistent so that remount can check the frozen state. Otherwise a crash reported here can happen: http://lkml.org/lkml/2010/1/16/37 http://lkml.org/lkml/2010/1/28/53 This patch should be applied for 2.6.32 stable series, too. Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Thomas Backlund <tmb@mandriva.org> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: stable@kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1621 lines
38 KiB
C
1621 lines
38 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/smp_lock.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/buffer_head.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/kmemleak.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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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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static void kill_bdev(struct block_device *bdev)
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{
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if (bdev->bd_inode->i_mapping->nrpages == 0)
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return;
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invalidate_bh_lrus();
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truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
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}
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int set_blocksize(struct block_device *bdev, int size)
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{
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/* Size must be a power of two, and between 512 and PAGE_SIZE */
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if (size > PAGE_SIZE || size < 512 || !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_no_locking(rw, iocb, inode, I_BDEV(inode),
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iov, offset, nr_segs, blkdev_get_blocks, NULL);
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}
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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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if (sb->s_flags & MS_RDONLY) {
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sb->s_frozen = SB_FREEZE_TRANS;
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up_write(&sb->s_umount);
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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->s_frozen = SB_FREEZE_WRITE;
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smp_wmb();
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sync_filesystem(sb);
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sb->s_frozen = SB_FREEZE_TRANS;
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smp_wmb();
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sync_blockdev(sb->s_bdev);
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if (sb->s_op->freeze_fs) {
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error = sb->s_op->freeze_fs(sb);
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if (error) {
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printk(KERN_ERR
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"VFS:Filesystem freeze failed\n");
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sb->s_frozen = SB_UNFROZEN;
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deactivate_locked_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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}
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up_write(&sb->s_umount);
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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_unlock;
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error = 0;
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if (--bdev->bd_fsfreeze_count > 0)
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goto out_unlock;
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if (!sb)
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goto out_unlock;
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BUG_ON(sb->s_bdev != bdev);
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down_write(&sb->s_umount);
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if (sb->s_flags & MS_RDONLY)
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goto out_unfrozen;
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if (sb->s_op->unfreeze_fs) {
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error = sb->s_op->unfreeze_fs(sb);
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if (error) {
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printk(KERN_ERR
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"VFS:Filesystem thaw failed\n");
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sb->s_frozen = SB_FREEZE_TRANS;
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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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}
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out_unfrozen:
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sb->s_frozen = SB_UNFROZEN;
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smp_wmb();
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wake_up(&sb->s_wait_unfrozen);
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if (sb)
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deactivate_locked_super(sb);
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out_unlock:
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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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*pagep = NULL;
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return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
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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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switch (origin) {
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case 2:
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offset += size;
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break;
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case 1:
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offset += file->f_pos;
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}
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retval = -EINVAL;
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if (offset >= 0 && offset <= size) {
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if (offset != file->f_pos) {
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file->f_pos = offset;
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}
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retval = offset;
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}
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mutex_unlock(&bd_inode->i_mutex);
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return retval;
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}
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/*
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* Filp is never NULL; the only case when ->fsync() is called with
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* NULL first argument is nfsd_sync_dir() and that's not a directory.
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*/
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static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
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{
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struct block_device *bdev = I_BDEV(filp->f_mapping->host);
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int error;
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error = sync_blockdev(bdev);
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if (error)
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return error;
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error = blkdev_issue_flush(bdev, 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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|
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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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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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static void bdev_destroy_inode(struct inode *inode)
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{
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struct bdev_inode *bdi = BDEV_I(inode);
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kmem_cache_free(bdev_cachep, bdi);
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}
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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_list);
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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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}
|
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|
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static inline void __bd_forget(struct inode *inode)
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{
|
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list_del_init(&inode->i_devices);
|
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inode->i_bdev = NULL;
|
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inode->i_mapping = &inode->i_data;
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}
|
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|
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static void bdev_clear_inode(struct inode *inode)
|
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{
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struct block_device *bdev = &BDEV_I(inode)->bdev;
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struct list_head *p;
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spin_lock(&bdev_lock);
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while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
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__bd_forget(list_entry(p, struct inode, i_devices));
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}
|
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list_del_init(&bdev->bd_list);
|
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spin_unlock(&bdev_lock);
|
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}
|
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|
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static const struct super_operations bdev_sops = {
|
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.statfs = simple_statfs,
|
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.alloc_inode = bdev_alloc_inode,
|
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.destroy_inode = bdev_destroy_inode,
|
|
.drop_inode = generic_delete_inode,
|
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.clear_inode = bdev_clear_inode,
|
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};
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|
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static int bd_get_sb(struct file_system_type *fs_type,
|
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int flags, const char *dev_name, void *data, struct vfsmount *mnt)
|
|
{
|
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return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
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}
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|
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static struct file_system_type bd_type = {
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.name = "bdev",
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.get_sb = bd_get_sb,
|
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.kill_sb = kill_anon_super,
|
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};
|
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|
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struct super_block *blockdev_superblock __read_mostly;
|
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|
|
void __init bdev_cache_init(void)
|
|
{
|
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int err;
|
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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");
|
|
/*
|
|
* This vfsmount structure is only used to obtain the
|
|
* blockdev_superblock, so tell kmemleak not to report it.
|
|
*/
|
|
kmemleak_not_leak(bd_mnt);
|
|
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_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)
|
|
{
|
|
atomic_inc(&bdev->bd_inode->i_count);
|
|
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) {
|
|
atomic_inc(&bdev->bd_inode->i_count);
|
|
spin_unlock(&bdev_lock);
|
|
return bdev;
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
|
|
bdev = bdget(inode->i_rdev);
|
|
if (bdev) {
|
|
spin_lock(&bdev_lock);
|
|
if (!inode->i_bdev) {
|
|
/*
|
|
* We take an additional bd_inode->i_count for inode,
|
|
* and it's released in clear_inode() of inode.
|
|
* So, we can access it via ->i_mapping always
|
|
* without igrab().
|
|
*/
|
|
atomic_inc(&bdev->bd_inode->i_count);
|
|
inode->i_bdev = bdev;
|
|
inode->i_mapping = bdev->bd_inode->i_mapping;
|
|
list_add(&inode->i_devices, &bdev->bd_inodes);
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
}
|
|
return bdev;
|
|
}
|
|
|
|
/* Call when you free inode */
|
|
|
|
void bd_forget(struct inode *inode)
|
|
{
|
|
struct block_device *bdev = NULL;
|
|
|
|
spin_lock(&bdev_lock);
|
|
if (inode->i_bdev) {
|
|
if (!sb_is_blkdev_sb(inode->i_sb))
|
|
bdev = inode->i_bdev;
|
|
__bd_forget(inode);
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
|
|
if (bdev)
|
|
iput(bdev->bd_inode);
|
|
}
|
|
|
|
int bd_claim(struct block_device *bdev, void *holder)
|
|
{
|
|
int res;
|
|
spin_lock(&bdev_lock);
|
|
|
|
/* first decide result */
|
|
if (bdev->bd_holder == holder)
|
|
res = 0; /* already a holder */
|
|
else if (bdev->bd_holder != NULL)
|
|
res = -EBUSY; /* held by someone else */
|
|
else if (bdev->bd_contains == bdev)
|
|
res = 0; /* is a whole device which isn't held */
|
|
|
|
else if (bdev->bd_contains->bd_holder == bd_claim)
|
|
res = 0; /* is a partition of a device that is being partitioned */
|
|
else if (bdev->bd_contains->bd_holder != NULL)
|
|
res = -EBUSY; /* is a partition of a held device */
|
|
else
|
|
res = 0; /* is a partition of an un-held device */
|
|
|
|
/* now impose change */
|
|
if (res==0) {
|
|
/* note that for a whole device bd_holders
|
|
* will be incremented twice, and bd_holder will
|
|
* be set to bd_claim before being set to holder
|
|
*/
|
|
bdev->bd_contains->bd_holders ++;
|
|
bdev->bd_contains->bd_holder = bd_claim;
|
|
bdev->bd_holders++;
|
|
bdev->bd_holder = holder;
|
|
}
|
|
spin_unlock(&bdev_lock);
|
|
return res;
|
|
}
|
|
|
|
EXPORT_SYMBOL(bd_claim);
|
|
|
|
void bd_release(struct block_device *bdev)
|
|
{
|
|
spin_lock(&bdev_lock);
|
|
if (!--bdev->bd_contains->bd_holders)
|
|
bdev->bd_contains->bd_holder = NULL;
|
|
if (!--bdev->bd_holders)
|
|
bdev->bd_holder = NULL;
|
|
spin_unlock(&bdev_lock);
|
|
}
|
|
|
|
EXPORT_SYMBOL(bd_release);
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
/*
|
|
* Functions for bd_claim_by_kobject / bd_release_from_kobject
|
|
*
|
|
* If a kobject is passed to bd_claim_by_kobject()
|
|
* and the kobject has a parent directory,
|
|
* following symlinks are created:
|
|
* o from the kobject to the claimed bdev
|
|
* o from "holders" directory of the bdev to the parent of the kobject
|
|
* bd_release_from_kobject() removes these symlinks.
|
|
*
|
|
* Example:
|
|
* If /dev/dm-0 maps to /dev/sda, kobject corresponding to
|
|
* /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
|
|
* /sys/block/dm-0/slaves/sda --> /sys/block/sda
|
|
* /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
|
|
*/
|
|
|
|
static int add_symlink(struct kobject *from, struct kobject *to)
|
|
{
|
|
if (!from || !to)
|
|
return 0;
|
|
return sysfs_create_link(from, to, kobject_name(to));
|
|
}
|
|
|
|
static void del_symlink(struct kobject *from, struct kobject *to)
|
|
{
|
|
if (!from || !to)
|
|
return;
|
|
sysfs_remove_link(from, kobject_name(to));
|
|
}
|
|
|
|
/*
|
|
* 'struct bd_holder' contains pointers to kobjects symlinked by
|
|
* bd_claim_by_kobject.
|
|
* It's connected to bd_holder_list which is protected by bdev->bd_sem.
|
|
*/
|
|
struct bd_holder {
|
|
struct list_head list; /* chain of holders of the bdev */
|
|
int count; /* references from the holder */
|
|
struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
|
|
struct kobject *hdev; /* e.g. "/block/dm-0" */
|
|
struct kobject *hdir; /* e.g. "/block/sda/holders" */
|
|
struct kobject *sdev; /* e.g. "/block/sda" */
|
|
};
|
|
|
|
/*
|
|
* Get references of related kobjects at once.
|
|
* Returns 1 on success. 0 on failure.
|
|
*
|
|
* Should call bd_holder_release_dirs() after successful use.
|
|
*/
|
|
static int bd_holder_grab_dirs(struct block_device *bdev,
|
|
struct bd_holder *bo)
|
|
{
|
|
if (!bdev || !bo)
|
|
return 0;
|
|
|
|
bo->sdir = kobject_get(bo->sdir);
|
|
if (!bo->sdir)
|
|
return 0;
|
|
|
|
bo->hdev = kobject_get(bo->sdir->parent);
|
|
if (!bo->hdev)
|
|
goto fail_put_sdir;
|
|
|
|
bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
|
|
if (!bo->sdev)
|
|
goto fail_put_hdev;
|
|
|
|
bo->hdir = kobject_get(bdev->bd_part->holder_dir);
|
|
if (!bo->hdir)
|
|
goto fail_put_sdev;
|
|
|
|
return 1;
|
|
|
|
fail_put_sdev:
|
|
kobject_put(bo->sdev);
|
|
fail_put_hdev:
|
|
kobject_put(bo->hdev);
|
|
fail_put_sdir:
|
|
kobject_put(bo->sdir);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Put references of related kobjects at once. */
|
|
static void bd_holder_release_dirs(struct bd_holder *bo)
|
|
{
|
|
kobject_put(bo->hdir);
|
|
kobject_put(bo->sdev);
|
|
kobject_put(bo->hdev);
|
|
kobject_put(bo->sdir);
|
|
}
|
|
|
|
static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
|
|
{
|
|
struct bd_holder *bo;
|
|
|
|
bo = kzalloc(sizeof(*bo), GFP_KERNEL);
|
|
if (!bo)
|
|
return NULL;
|
|
|
|
bo->count = 1;
|
|
bo->sdir = kobj;
|
|
|
|
return bo;
|
|
}
|
|
|
|
static void free_bd_holder(struct bd_holder *bo)
|
|
{
|
|
kfree(bo);
|
|
}
|
|
|
|
/**
|
|
* find_bd_holder - find matching struct bd_holder from the block device
|
|
*
|
|
* @bdev: struct block device to be searched
|
|
* @bo: target struct bd_holder
|
|
*
|
|
* Returns matching entry with @bo in @bdev->bd_holder_list.
|
|
* If found, increment the reference count and return the pointer.
|
|
* If not found, returns NULL.
|
|
*/
|
|
static struct bd_holder *find_bd_holder(struct block_device *bdev,
|
|
struct bd_holder *bo)
|
|
{
|
|
struct bd_holder *tmp;
|
|
|
|
list_for_each_entry(tmp, &bdev->bd_holder_list, list)
|
|
if (tmp->sdir == bo->sdir) {
|
|
tmp->count++;
|
|
return tmp;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* add_bd_holder - create sysfs symlinks for bd_claim() relationship
|
|
*
|
|
* @bdev: block device to be bd_claimed
|
|
* @bo: preallocated and initialized by alloc_bd_holder()
|
|
*
|
|
* Add @bo to @bdev->bd_holder_list, create symlinks.
|
|
*
|
|
* Returns 0 if symlinks are created.
|
|
* Returns -ve if something fails.
|
|
*/
|
|
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
|
|
{
|
|
int err;
|
|
|
|
if (!bo)
|
|
return -EINVAL;
|
|
|
|
if (!bd_holder_grab_dirs(bdev, bo))
|
|
return -EBUSY;
|
|
|
|
err = add_symlink(bo->sdir, bo->sdev);
|
|
if (err)
|
|
return err;
|
|
|
|
err = add_symlink(bo->hdir, bo->hdev);
|
|
if (err) {
|
|
del_symlink(bo->sdir, bo->sdev);
|
|
return err;
|
|
}
|
|
|
|
list_add_tail(&bo->list, &bdev->bd_holder_list);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* del_bd_holder - delete sysfs symlinks for bd_claim() relationship
|
|
*
|
|
* @bdev: block device to be bd_claimed
|
|
* @kobj: holder's kobject
|
|
*
|
|
* If there is matching entry with @kobj in @bdev->bd_holder_list
|
|
* and no other bd_claim() from the same kobject,
|
|
* remove the struct bd_holder from the list, delete symlinks for it.
|
|
*
|
|
* Returns a pointer to the struct bd_holder when it's removed from the list
|
|
* and ready to be freed.
|
|
* Returns NULL if matching claim isn't found or there is other bd_claim()
|
|
* by the same kobject.
|
|
*/
|
|
static struct bd_holder *del_bd_holder(struct block_device *bdev,
|
|
struct kobject *kobj)
|
|
{
|
|
struct bd_holder *bo;
|
|
|
|
list_for_each_entry(bo, &bdev->bd_holder_list, list) {
|
|
if (bo->sdir == kobj) {
|
|
bo->count--;
|
|
BUG_ON(bo->count < 0);
|
|
if (!bo->count) {
|
|
list_del(&bo->list);
|
|
del_symlink(bo->sdir, bo->sdev);
|
|
del_symlink(bo->hdir, bo->hdev);
|
|
bd_holder_release_dirs(bo);
|
|
return bo;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* bd_claim_by_kobject - bd_claim() with additional kobject signature
|
|
*
|
|
* @bdev: block device to be claimed
|
|
* @holder: holder's signature
|
|
* @kobj: holder's kobject
|
|
*
|
|
* Do bd_claim() and if it succeeds, create sysfs symlinks between
|
|
* the bdev and the holder's kobject.
|
|
* Use bd_release_from_kobject() when relesing the claimed bdev.
|
|
*
|
|
* Returns 0 on success. (same as bd_claim())
|
|
* Returns errno on failure.
|
|
*/
|
|
static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
|
|
struct kobject *kobj)
|
|
{
|
|
int err;
|
|
struct bd_holder *bo, *found;
|
|
|
|
if (!kobj)
|
|
return -EINVAL;
|
|
|
|
bo = alloc_bd_holder(kobj);
|
|
if (!bo)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
|
|
err = bd_claim(bdev, holder);
|
|
if (err)
|
|
goto fail;
|
|
|
|
found = find_bd_holder(bdev, bo);
|
|
if (found)
|
|
goto fail;
|
|
|
|
err = add_bd_holder(bdev, bo);
|
|
if (err)
|
|
bd_release(bdev);
|
|
else
|
|
bo = NULL;
|
|
fail:
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
free_bd_holder(bo);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* bd_release_from_kobject - bd_release() with additional kobject signature
|
|
*
|
|
* @bdev: block device to be released
|
|
* @kobj: holder's kobject
|
|
*
|
|
* Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
|
|
*/
|
|
static void bd_release_from_kobject(struct block_device *bdev,
|
|
struct kobject *kobj)
|
|
{
|
|
if (!kobj)
|
|
return;
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
bd_release(bdev);
|
|
free_bd_holder(del_bd_holder(bdev, kobj));
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
}
|
|
|
|
/**
|
|
* bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
|
|
*
|
|
* @bdev: block device to be claimed
|
|
* @holder: holder's signature
|
|
* @disk: holder's gendisk
|
|
*
|
|
* Call bd_claim_by_kobject() with getting @disk->slave_dir.
|
|
*/
|
|
int bd_claim_by_disk(struct block_device *bdev, void *holder,
|
|
struct gendisk *disk)
|
|
{
|
|
return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_claim_by_disk);
|
|
|
|
/**
|
|
* bd_release_from_disk - wrapper function for bd_release_from_kobject()
|
|
*
|
|
* @bdev: block device to be claimed
|
|
* @disk: holder's gendisk
|
|
*
|
|
* Call bd_release_from_kobject() and put @disk->slave_dir.
|
|
*/
|
|
void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
|
|
{
|
|
bd_release_from_kobject(bdev, disk->slave_dir);
|
|
kobject_put(disk->slave_dir);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_release_from_disk);
|
|
#endif
|
|
|
|
/*
|
|
* Tries to open block device by device number. Use it ONLY if you
|
|
* really do not have anything better - i.e. when you are behind a
|
|
* truly sucky interface and all you are given is a device number. _Never_
|
|
* to be used for internal purposes. If you ever need it - reconsider
|
|
* your API.
|
|
*/
|
|
struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
|
|
{
|
|
struct block_device *bdev = bdget(dev);
|
|
int err = -ENOMEM;
|
|
if (bdev)
|
|
err = blkdev_get(bdev, mode);
|
|
return err ? ERR_PTR(err) : bdev;
|
|
}
|
|
|
|
EXPORT_SYMBOL(open_by_devnum);
|
|
|
|
/**
|
|
* flush_disk - invalidates all buffer-cache entries on a disk
|
|
*
|
|
* @bdev: struct block device to be flushed
|
|
*
|
|
* 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)
|
|
{
|
|
if (__invalidate_device(bdev)) {
|
|
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_partitionable(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);
|
|
}
|
|
}
|
|
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;
|
|
|
|
if (!bdops->media_changed)
|
|
return 0;
|
|
if (!bdops->media_changed(bdev->bd_disk))
|
|
return 0;
|
|
|
|
flush_disk(bdev);
|
|
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;
|
|
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".
|
|
*/
|
|
ret = devcgroup_inode_permission(bdev->bd_inode, perm);
|
|
if (ret != 0) {
|
|
bdput(bdev);
|
|
return ret;
|
|
}
|
|
|
|
lock_kernel();
|
|
restart:
|
|
|
|
ret = -ENXIO;
|
|
disk = get_gendisk(bdev->bd_dev, &partno);
|
|
if (!disk)
|
|
goto out_unlock_kernel;
|
|
|
|
mutex_lock_nested(&bdev->bd_mutex, for_part);
|
|
if (!bdev->bd_openers) {
|
|
bdev->bd_disk = disk;
|
|
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;
|
|
|
|
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;
|
|
module_put(disk->fops->owner);
|
|
put_disk(disk);
|
|
bdev->bd_disk = NULL;
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
goto restart;
|
|
}
|
|
if (ret)
|
|
goto out_clear;
|
|
}
|
|
if (!bdev->bd_openers) {
|
|
bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
|
|
bdi = blk_get_backing_dev_info(bdev);
|
|
if (bdi == NULL)
|
|
bdi = &default_backing_dev_info;
|
|
bdev->bd_inode->i_data.backing_dev_info = bdi;
|
|
}
|
|
if (bdev->bd_invalidated)
|
|
rescan_partitions(disk, bdev);
|
|
} else {
|
|
struct 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->bd_inode->i_data.backing_dev_info =
|
|
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 {
|
|
module_put(disk->fops->owner);
|
|
put_disk(disk);
|
|
disk = NULL;
|
|
if (bdev->bd_contains == bdev) {
|
|
if (bdev->bd_disk->fops->open) {
|
|
ret = bdev->bd_disk->fops->open(bdev, mode);
|
|
if (ret)
|
|
goto out_unlock_bdev;
|
|
}
|
|
if (bdev->bd_invalidated)
|
|
rescan_partitions(bdev->bd_disk, bdev);
|
|
}
|
|
}
|
|
bdev->bd_openers++;
|
|
if (for_part)
|
|
bdev->bd_part_count++;
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
unlock_kernel();
|
|
return 0;
|
|
|
|
out_clear:
|
|
disk_put_part(bdev->bd_part);
|
|
bdev->bd_disk = NULL;
|
|
bdev->bd_part = NULL;
|
|
bdev->bd_inode->i_data.backing_dev_info = &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);
|
|
out_unlock_kernel:
|
|
unlock_kernel();
|
|
|
|
if (disk)
|
|
module_put(disk->fops->owner);
|
|
put_disk(disk);
|
|
bdput(bdev);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int blkdev_get(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
return __blkdev_get(bdev, mode, 0);
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get);
|
|
|
|
static int blkdev_open(struct inode * inode, struct file * filp)
|
|
{
|
|
struct block_device *bdev;
|
|
int res;
|
|
|
|
/*
|
|
* Preserve backwards compatibility and allow large file access
|
|
* even if userspace doesn't ask for it explicitly. Some mkfs
|
|
* binary needs it. We might want to drop this workaround
|
|
* during an unstable branch.
|
|
*/
|
|
filp->f_flags |= O_LARGEFILE;
|
|
|
|
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;
|
|
|
|
res = blkdev_get(bdev, filp->f_mode);
|
|
if (res)
|
|
return res;
|
|
|
|
if (filp->f_mode & FMODE_EXCL) {
|
|
res = bd_claim(bdev, filp);
|
|
if (res)
|
|
goto out_blkdev_put;
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_blkdev_put:
|
|
blkdev_put(bdev, filp->f_mode);
|
|
return res;
|
|
}
|
|
|
|
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);
|
|
lock_kernel();
|
|
if (for_part)
|
|
bdev->bd_part_count--;
|
|
|
|
if (!--bdev->bd_openers) {
|
|
sync_blockdev(bdev);
|
|
kill_bdev(bdev);
|
|
}
|
|
if (bdev->bd_contains == bdev) {
|
|
if (disk->fops->release)
|
|
ret = disk->fops->release(disk, mode);
|
|
}
|
|
if (!bdev->bd_openers) {
|
|
struct module *owner = disk->fops->owner;
|
|
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
disk_put_part(bdev->bd_part);
|
|
bdev->bd_part = NULL;
|
|
bdev->bd_disk = NULL;
|
|
bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
|
|
if (bdev != bdev->bd_contains)
|
|
victim = bdev->bd_contains;
|
|
bdev->bd_contains = NULL;
|
|
}
|
|
unlock_kernel();
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(bdev);
|
|
if (victim)
|
|
__blkdev_put(victim, mode, 1);
|
|
return ret;
|
|
}
|
|
|
|
int blkdev_put(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
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);
|
|
if (bdev->bd_holder == filp)
|
|
bd_release(bdev);
|
|
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,
|
|
.sync_page = block_sync_page,
|
|
.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 = block_fsync,
|
|
.unlocked_ioctl = block_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = compat_blkdev_ioctl,
|
|
#endif
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = generic_file_splice_write,
|
|
};
|
|
|
|
int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
|
|
{
|
|
int res;
|
|
mm_segment_t old_fs = get_fs();
|
|
set_fs(KERNEL_DS);
|
|
res = blkdev_ioctl(bdev, 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);
|
|
|
|
/**
|
|
* open_bdev_exclusive - open a block device by name and set it up for use
|
|
*
|
|
* @path: special file representing the block device
|
|
* @mode: FMODE_... combination to pass be used
|
|
* @holder: owner for exclusion
|
|
*
|
|
* Open the blockdevice described by the special file at @path, claim it
|
|
* for the @holder.
|
|
*/
|
|
struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
|
|
{
|
|
struct block_device *bdev;
|
|
int error = 0;
|
|
|
|
bdev = lookup_bdev(path);
|
|
if (IS_ERR(bdev))
|
|
return bdev;
|
|
|
|
error = blkdev_get(bdev, mode);
|
|
if (error)
|
|
return ERR_PTR(error);
|
|
error = -EACCES;
|
|
if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
|
|
goto blkdev_put;
|
|
error = bd_claim(bdev, holder);
|
|
if (error)
|
|
goto blkdev_put;
|
|
|
|
return bdev;
|
|
|
|
blkdev_put:
|
|
blkdev_put(bdev, mode);
|
|
return ERR_PTR(error);
|
|
}
|
|
|
|
EXPORT_SYMBOL(open_bdev_exclusive);
|
|
|
|
/**
|
|
* close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
|
|
*
|
|
* @bdev: blockdevice to close
|
|
* @mode: mode, must match that used to open.
|
|
*
|
|
* This is the counterpart to open_bdev_exclusive().
|
|
*/
|
|
void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
bd_release(bdev);
|
|
blkdev_put(bdev, mode);
|
|
}
|
|
|
|
EXPORT_SYMBOL(close_bdev_exclusive);
|
|
|
|
int __invalidate_device(struct block_device *bdev)
|
|
{
|
|
struct super_block *sb = get_super(bdev);
|
|
int res = 0;
|
|
|
|
if (sb) {
|
|
/*
|
|
* no need to lock the super, get_super holds the
|
|
* read mutex so the filesystem cannot go away
|
|
* under us (->put_super runs with the write lock
|
|
* hold).
|
|
*/
|
|
shrink_dcache_sb(sb);
|
|
res = invalidate_inodes(sb);
|
|
drop_super(sb);
|
|
}
|
|
invalidate_bdev(bdev);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(__invalidate_device);
|