1054 lines
27 KiB
C
1054 lines
27 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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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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* Copyright (C) 2016 - 2020 Christoph Hellwig
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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/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/blkdev.h>
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#include <linux/blk-integrity.h>
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#include <linux/backing-dev.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/writeback.h>
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#include <linux/mount.h>
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#include <linux/pseudo_fs.h>
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#include <linux/uio.h>
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#include <linux/namei.h>
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#include <linux/part_stat.h>
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#include <linux/uaccess.h>
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#include <linux/stat.h>
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#include "../fs/internal.h"
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#include "blk.h"
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struct bdev_inode {
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struct block_device bdev;
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struct inode vfs_inode;
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};
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static inline struct bdev_inode *BDEV_I(struct inode *inode)
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{
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return container_of(inode, struct bdev_inode, vfs_inode);
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}
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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 void bdev_write_inode(struct block_device *bdev)
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{
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struct inode *inode = bdev->bd_inode;
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int ret;
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spin_lock(&inode->i_lock);
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while (inode->i_state & I_DIRTY) {
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spin_unlock(&inode->i_lock);
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ret = write_inode_now(inode, true);
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if (ret)
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pr_warn_ratelimited(
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"VFS: Dirty inode writeback failed for block device %pg (err=%d).\n",
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bdev, ret);
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spin_lock(&inode->i_lock);
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}
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spin_unlock(&inode->i_lock);
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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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struct address_space *mapping = bdev->bd_inode->i_mapping;
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if (mapping_empty(mapping))
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return;
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invalidate_bh_lrus();
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truncate_inode_pages(mapping, 0);
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}
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/* Invalidate clean unused buffers and pagecache. */
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void invalidate_bdev(struct block_device *bdev)
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{
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struct address_space *mapping = bdev->bd_inode->i_mapping;
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if (mapping->nrpages) {
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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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}
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}
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EXPORT_SYMBOL(invalidate_bdev);
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/*
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* Drop all buffers & page cache for given bdev range. This function bails
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* with error if bdev has other exclusive owner (such as filesystem).
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*/
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int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode,
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loff_t lstart, loff_t lend)
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{
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/*
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* If we don't hold exclusive handle for the device, upgrade to it
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* while we discard the buffer cache to avoid discarding buffers
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* under live filesystem.
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*/
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if (!(mode & BLK_OPEN_EXCL)) {
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int err = bd_prepare_to_claim(bdev, truncate_bdev_range, NULL);
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if (err)
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goto invalidate;
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}
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truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
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if (!(mode & BLK_OPEN_EXCL))
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bd_abort_claiming(bdev, truncate_bdev_range);
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return 0;
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invalidate:
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/*
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* Someone else has handle exclusively open. Try invalidating instead.
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* The 'end' argument is inclusive so the rounding is safe.
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*/
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return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
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lstart >> PAGE_SHIFT,
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lend >> PAGE_SHIFT);
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}
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static void set_init_blocksize(struct block_device *bdev)
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{
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unsigned int bsize = bdev_logical_block_size(bdev);
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loff_t size = i_size_read(bdev->bd_inode);
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while (bsize < PAGE_SIZE) {
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if (size & bsize)
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break;
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bsize <<= 1;
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}
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bdev->bd_inode->i_blkbits = blksize_bits(bsize);
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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_inode->i_blkbits != blksize_bits(size)) {
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sync_blockdev(bdev);
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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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int sync_blockdev_nowait(struct block_device *bdev)
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{
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if (!bdev)
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return 0;
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return filemap_flush(bdev->bd_inode->i_mapping);
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}
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EXPORT_SYMBOL_GPL(sync_blockdev_nowait);
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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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if (!bdev)
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return 0;
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return filemap_write_and_wait(bdev->bd_inode->i_mapping);
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}
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EXPORT_SYMBOL(sync_blockdev);
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int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend)
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{
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return filemap_write_and_wait_range(bdev->bd_inode->i_mapping,
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lstart, lend);
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}
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EXPORT_SYMBOL(sync_blockdev_range);
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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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int 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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goto done;
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sb = get_active_super(bdev);
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if (!sb)
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goto sync;
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if (sb->s_op->freeze_super)
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error = sb->s_op->freeze_super(sb, FREEZE_HOLDER_USERSPACE);
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else
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error = freeze_super(sb, FREEZE_HOLDER_USERSPACE);
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deactivate_super(sb);
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if (error) {
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bdev->bd_fsfreeze_count--;
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goto done;
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}
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bdev->bd_fsfreeze_sb = sb;
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sync:
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sync_blockdev(bdev);
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done:
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return error;
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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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*
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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)
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{
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struct super_block *sb;
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int error = -EINVAL;
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mutex_lock(&bdev->bd_fsfreeze_mutex);
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if (!bdev->bd_fsfreeze_count)
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goto out;
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error = 0;
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if (--bdev->bd_fsfreeze_count > 0)
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goto out;
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sb = bdev->bd_fsfreeze_sb;
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if (!sb)
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goto out;
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if (sb->s_op->thaw_super)
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error = sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE);
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else
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error = thaw_super(sb, FREEZE_HOLDER_USERSPACE);
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if (error)
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bdev->bd_fsfreeze_count++;
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else
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bdev->bd_fsfreeze_sb = NULL;
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out:
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mutex_unlock(&bdev->bd_fsfreeze_mutex);
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return error;
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}
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EXPORT_SYMBOL(thaw_bdev);
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/*
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* pseudo-fs
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*/
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static __cacheline_aligned_in_smp DEFINE_MUTEX(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 = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL);
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if (!ei)
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return NULL;
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memset(&ei->bdev, 0, sizeof(ei->bdev));
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return &ei->vfs_inode;
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}
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static void bdev_free_inode(struct inode *inode)
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{
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struct block_device *bdev = I_BDEV(inode);
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free_percpu(bdev->bd_stats);
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kfree(bdev->bd_meta_info);
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if (!bdev_is_partition(bdev)) {
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if (bdev->bd_disk && bdev->bd_disk->bdi)
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bdi_put(bdev->bd_disk->bdi);
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kfree(bdev->bd_disk);
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}
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if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
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blk_free_ext_minor(MINOR(bdev->bd_dev));
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kmem_cache_free(bdev_cachep, BDEV_I(inode));
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}
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static void init_once(void *data)
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{
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struct bdev_inode *ei = data;
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inode_init_once(&ei->vfs_inode);
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}
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static void bdev_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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invalidate_inode_buffers(inode); /* is it needed here? */
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clear_inode(inode);
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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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.free_inode = bdev_free_inode,
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.drop_inode = generic_delete_inode,
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.evict_inode = bdev_evict_inode,
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};
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static int bd_init_fs_context(struct fs_context *fc)
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{
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struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
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if (!ctx)
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return -ENOMEM;
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fc->s_iflags |= SB_I_CGROUPWB;
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ctx->ops = &bdev_sops;
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return 0;
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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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.init_fs_context = bd_init_fs_context,
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.kill_sb = kill_anon_super,
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};
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struct super_block *blockdev_superblock __read_mostly;
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EXPORT_SYMBOL_GPL(blockdev_superblock);
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void __init bdev_cache_init(void)
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{
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int err;
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static struct vfsmount *bd_mnt;
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bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
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0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC),
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init_once);
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err = register_filesystem(&bd_type);
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if (err)
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panic("Cannot register bdev pseudo-fs");
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bd_mnt = kern_mount(&bd_type);
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if (IS_ERR(bd_mnt))
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panic("Cannot create bdev pseudo-fs");
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blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
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}
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struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
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{
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struct block_device *bdev;
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struct inode *inode;
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inode = new_inode(blockdev_superblock);
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if (!inode)
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return NULL;
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inode->i_mode = S_IFBLK;
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inode->i_rdev = 0;
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inode->i_data.a_ops = &def_blk_aops;
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mapping_set_gfp_mask(&inode->i_data, GFP_USER);
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bdev = I_BDEV(inode);
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mutex_init(&bdev->bd_fsfreeze_mutex);
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spin_lock_init(&bdev->bd_size_lock);
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mutex_init(&bdev->bd_holder_lock);
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bdev->bd_partno = partno;
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bdev->bd_inode = inode;
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bdev->bd_queue = disk->queue;
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if (partno)
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bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio;
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else
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bdev->bd_has_submit_bio = false;
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bdev->bd_stats = alloc_percpu(struct disk_stats);
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if (!bdev->bd_stats) {
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iput(inode);
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return NULL;
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}
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bdev->bd_disk = disk;
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return bdev;
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}
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void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
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{
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spin_lock(&bdev->bd_size_lock);
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i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
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bdev->bd_nr_sectors = sectors;
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spin_unlock(&bdev->bd_size_lock);
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}
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void bdev_add(struct block_device *bdev, dev_t dev)
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{
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if (bdev_stable_writes(bdev))
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mapping_set_stable_writes(bdev->bd_inode->i_mapping);
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bdev->bd_dev = dev;
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bdev->bd_inode->i_rdev = dev;
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bdev->bd_inode->i_ino = dev;
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insert_inode_hash(bdev->bd_inode);
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}
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long nr_blockdev_pages(void)
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{
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struct inode *inode;
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long ret = 0;
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spin_lock(&blockdev_superblock->s_inode_list_lock);
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list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
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ret += inode->i_mapping->nrpages;
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spin_unlock(&blockdev_superblock->s_inode_list_lock);
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return ret;
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}
|
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|
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/**
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* bd_may_claim - test whether a block device can be claimed
|
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* @bdev: block device of interest
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* @holder: holder trying to claim @bdev
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* @hops: holder ops
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*
|
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* Test whether @bdev can be claimed by @holder.
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*
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* RETURNS:
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* %true if @bdev can be claimed, %false otherwise.
|
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*/
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static bool bd_may_claim(struct block_device *bdev, void *holder,
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const struct blk_holder_ops *hops)
|
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{
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struct block_device *whole = bdev_whole(bdev);
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|
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lockdep_assert_held(&bdev_lock);
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|
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if (bdev->bd_holder) {
|
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/*
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* The same holder can always re-claim.
|
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*/
|
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if (bdev->bd_holder == holder) {
|
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if (WARN_ON_ONCE(bdev->bd_holder_ops != hops))
|
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return false;
|
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return true;
|
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}
|
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return false;
|
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}
|
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|
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/*
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* If the whole devices holder is set to bd_may_claim, a partition on
|
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* the device is claimed, but not the whole device.
|
|
*/
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if (whole != bdev &&
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whole->bd_holder && whole->bd_holder != bd_may_claim)
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return false;
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return true;
|
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}
|
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|
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/**
|
|
* bd_prepare_to_claim - claim a block device
|
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* @bdev: block device of interest
|
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* @holder: holder trying to claim @bdev
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* @hops: holder ops.
|
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*
|
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* Claim @bdev. This function fails if @bdev is already claimed by another
|
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* holder and waits if another claiming is in progress. return, the caller
|
|
* has ownership of bd_claiming and bd_holder[s].
|
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*
|
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* RETURNS:
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* 0 if @bdev can be claimed, -EBUSY otherwise.
|
|
*/
|
|
int bd_prepare_to_claim(struct block_device *bdev, void *holder,
|
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const struct blk_holder_ops *hops)
|
|
{
|
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struct block_device *whole = bdev_whole(bdev);
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|
|
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if (WARN_ON_ONCE(!holder))
|
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return -EINVAL;
|
|
retry:
|
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mutex_lock(&bdev_lock);
|
|
/* if someone else claimed, fail */
|
|
if (!bd_may_claim(bdev, holder, hops)) {
|
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mutex_unlock(&bdev_lock);
|
|
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);
|
|
mutex_unlock(&bdev_lock);
|
|
schedule();
|
|
finish_wait(wq, &wait);
|
|
goto retry;
|
|
}
|
|
|
|
/* yay, all mine */
|
|
whole->bd_claiming = holder;
|
|
mutex_unlock(&bdev_lock);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
|
|
|
|
static void bd_clear_claiming(struct block_device *whole, void *holder)
|
|
{
|
|
lockdep_assert_held(&bdev_lock);
|
|
/* tell others that we're done */
|
|
BUG_ON(whole->bd_claiming != holder);
|
|
whole->bd_claiming = NULL;
|
|
wake_up_bit(&whole->bd_claiming, 0);
|
|
}
|
|
|
|
/**
|
|
* bd_finish_claiming - finish claiming of a block device
|
|
* @bdev: block device of interest
|
|
* @holder: holder that has claimed @bdev
|
|
* @hops: block device holder operations
|
|
*
|
|
* Finish exclusive open of a block device. Mark the device as exlusively
|
|
* open by the holder and wake up all waiters for exclusive open to finish.
|
|
*/
|
|
static void bd_finish_claiming(struct block_device *bdev, void *holder,
|
|
const struct blk_holder_ops *hops)
|
|
{
|
|
struct block_device *whole = bdev_whole(bdev);
|
|
|
|
mutex_lock(&bdev_lock);
|
|
BUG_ON(!bd_may_claim(bdev, holder, hops));
|
|
/*
|
|
* 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++;
|
|
mutex_lock(&bdev->bd_holder_lock);
|
|
bdev->bd_holder = holder;
|
|
bdev->bd_holder_ops = hops;
|
|
mutex_unlock(&bdev->bd_holder_lock);
|
|
bd_clear_claiming(whole, holder);
|
|
mutex_unlock(&bdev_lock);
|
|
}
|
|
|
|
/**
|
|
* bd_abort_claiming - abort claiming of a block device
|
|
* @bdev: block device of interest
|
|
* @holder: holder that has claimed @bdev
|
|
*
|
|
* Abort claiming of a block device when the exclusive open failed. This can be
|
|
* also used when exclusive open is not actually desired and we just needed
|
|
* to block other exclusive openers for a while.
|
|
*/
|
|
void bd_abort_claiming(struct block_device *bdev, void *holder)
|
|
{
|
|
mutex_lock(&bdev_lock);
|
|
bd_clear_claiming(bdev_whole(bdev), holder);
|
|
mutex_unlock(&bdev_lock);
|
|
}
|
|
EXPORT_SYMBOL(bd_abort_claiming);
|
|
|
|
static void bd_end_claim(struct block_device *bdev, void *holder)
|
|
{
|
|
struct block_device *whole = bdev_whole(bdev);
|
|
bool unblock = false;
|
|
|
|
/*
|
|
* Release a claim on the device. The holder fields are protected with
|
|
* bdev_lock. open_mutex is used to synchronize disk_holder unlinking.
|
|
*/
|
|
mutex_lock(&bdev_lock);
|
|
WARN_ON_ONCE(bdev->bd_holder != holder);
|
|
WARN_ON_ONCE(--bdev->bd_holders < 0);
|
|
WARN_ON_ONCE(--whole->bd_holders < 0);
|
|
if (!bdev->bd_holders) {
|
|
mutex_lock(&bdev->bd_holder_lock);
|
|
bdev->bd_holder = NULL;
|
|
bdev->bd_holder_ops = NULL;
|
|
mutex_unlock(&bdev->bd_holder_lock);
|
|
if (bdev->bd_write_holder)
|
|
unblock = true;
|
|
}
|
|
if (!whole->bd_holders)
|
|
whole->bd_holder = NULL;
|
|
mutex_unlock(&bdev_lock);
|
|
|
|
/*
|
|
* If this was the last claim, remove holder link and unblock evpoll if
|
|
* it was a write holder.
|
|
*/
|
|
if (unblock) {
|
|
disk_unblock_events(bdev->bd_disk);
|
|
bdev->bd_write_holder = false;
|
|
}
|
|
}
|
|
|
|
static void blkdev_flush_mapping(struct block_device *bdev)
|
|
{
|
|
WARN_ON_ONCE(bdev->bd_holders);
|
|
sync_blockdev(bdev);
|
|
kill_bdev(bdev);
|
|
bdev_write_inode(bdev);
|
|
}
|
|
|
|
static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
|
|
{
|
|
struct gendisk *disk = bdev->bd_disk;
|
|
int ret;
|
|
|
|
if (disk->fops->open) {
|
|
ret = disk->fops->open(disk, mode);
|
|
if (ret) {
|
|
/* avoid ghost partitions on a removed medium */
|
|
if (ret == -ENOMEDIUM &&
|
|
test_bit(GD_NEED_PART_SCAN, &disk->state))
|
|
bdev_disk_changed(disk, true);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
if (!atomic_read(&bdev->bd_openers))
|
|
set_init_blocksize(bdev);
|
|
if (test_bit(GD_NEED_PART_SCAN, &disk->state))
|
|
bdev_disk_changed(disk, false);
|
|
atomic_inc(&bdev->bd_openers);
|
|
return 0;
|
|
}
|
|
|
|
static void blkdev_put_whole(struct block_device *bdev)
|
|
{
|
|
if (atomic_dec_and_test(&bdev->bd_openers))
|
|
blkdev_flush_mapping(bdev);
|
|
if (bdev->bd_disk->fops->release)
|
|
bdev->bd_disk->fops->release(bdev->bd_disk);
|
|
}
|
|
|
|
static int blkdev_get_part(struct block_device *part, blk_mode_t mode)
|
|
{
|
|
struct gendisk *disk = part->bd_disk;
|
|
int ret;
|
|
|
|
ret = blkdev_get_whole(bdev_whole(part), mode);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = -ENXIO;
|
|
if (!bdev_nr_sectors(part))
|
|
goto out_blkdev_put;
|
|
|
|
if (!atomic_read(&part->bd_openers)) {
|
|
disk->open_partitions++;
|
|
set_init_blocksize(part);
|
|
}
|
|
atomic_inc(&part->bd_openers);
|
|
return 0;
|
|
|
|
out_blkdev_put:
|
|
blkdev_put_whole(bdev_whole(part));
|
|
return ret;
|
|
}
|
|
|
|
static void blkdev_put_part(struct block_device *part)
|
|
{
|
|
struct block_device *whole = bdev_whole(part);
|
|
|
|
if (atomic_dec_and_test(&part->bd_openers)) {
|
|
blkdev_flush_mapping(part);
|
|
whole->bd_disk->open_partitions--;
|
|
}
|
|
blkdev_put_whole(whole);
|
|
}
|
|
|
|
struct block_device *blkdev_get_no_open(dev_t dev)
|
|
{
|
|
struct block_device *bdev;
|
|
struct inode *inode;
|
|
|
|
inode = ilookup(blockdev_superblock, dev);
|
|
if (!inode && IS_ENABLED(CONFIG_BLOCK_LEGACY_AUTOLOAD)) {
|
|
blk_request_module(dev);
|
|
inode = ilookup(blockdev_superblock, dev);
|
|
if (inode)
|
|
pr_warn_ratelimited(
|
|
"block device autoloading is deprecated and will be removed.\n");
|
|
}
|
|
if (!inode)
|
|
return NULL;
|
|
|
|
/* switch from the inode reference to a device mode one: */
|
|
bdev = &BDEV_I(inode)->bdev;
|
|
if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
|
|
bdev = NULL;
|
|
iput(inode);
|
|
return bdev;
|
|
}
|
|
|
|
void blkdev_put_no_open(struct block_device *bdev)
|
|
{
|
|
put_device(&bdev->bd_device);
|
|
}
|
|
|
|
/**
|
|
* blkdev_get_by_dev - open a block device by device number
|
|
* @dev: device number of block device to open
|
|
* @mode: open mode (BLK_OPEN_*)
|
|
* @holder: exclusive holder identifier
|
|
* @hops: holder operations
|
|
*
|
|
* Open the block device described by device number @dev. If @holder is not
|
|
* %NULL, the block device is opened with exclusive access. Exclusive opens may
|
|
* nest for the same @holder.
|
|
*
|
|
* Use this interface 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. Everything else should use blkdev_get_by_path().
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* Reference to the block_device on success, ERR_PTR(-errno) on failure.
|
|
*/
|
|
struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,
|
|
const struct blk_holder_ops *hops)
|
|
{
|
|
bool unblock_events = true;
|
|
struct block_device *bdev;
|
|
struct gendisk *disk;
|
|
int ret;
|
|
|
|
ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
|
|
MAJOR(dev), MINOR(dev),
|
|
((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) |
|
|
((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0));
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
bdev = blkdev_get_no_open(dev);
|
|
if (!bdev)
|
|
return ERR_PTR(-ENXIO);
|
|
disk = bdev->bd_disk;
|
|
|
|
if (holder) {
|
|
mode |= BLK_OPEN_EXCL;
|
|
ret = bd_prepare_to_claim(bdev, holder, hops);
|
|
if (ret)
|
|
goto put_blkdev;
|
|
} else {
|
|
if (WARN_ON_ONCE(mode & BLK_OPEN_EXCL)) {
|
|
ret = -EIO;
|
|
goto put_blkdev;
|
|
}
|
|
}
|
|
|
|
disk_block_events(disk);
|
|
|
|
mutex_lock(&disk->open_mutex);
|
|
ret = -ENXIO;
|
|
if (!disk_live(disk))
|
|
goto abort_claiming;
|
|
if (!try_module_get(disk->fops->owner))
|
|
goto abort_claiming;
|
|
if (bdev_is_partition(bdev))
|
|
ret = blkdev_get_part(bdev, mode);
|
|
else
|
|
ret = blkdev_get_whole(bdev, mode);
|
|
if (ret)
|
|
goto put_module;
|
|
if (holder) {
|
|
bd_finish_claiming(bdev, holder, hops);
|
|
|
|
/*
|
|
* 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 ((mode & BLK_OPEN_WRITE) && !bdev->bd_write_holder &&
|
|
(disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
|
|
bdev->bd_write_holder = true;
|
|
unblock_events = false;
|
|
}
|
|
}
|
|
mutex_unlock(&disk->open_mutex);
|
|
|
|
if (unblock_events)
|
|
disk_unblock_events(disk);
|
|
return bdev;
|
|
put_module:
|
|
module_put(disk->fops->owner);
|
|
abort_claiming:
|
|
if (holder)
|
|
bd_abort_claiming(bdev, holder);
|
|
mutex_unlock(&disk->open_mutex);
|
|
disk_unblock_events(disk);
|
|
put_blkdev:
|
|
blkdev_put_no_open(bdev);
|
|
return ERR_PTR(ret);
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get_by_dev);
|
|
|
|
/**
|
|
* blkdev_get_by_path - open a block device by name
|
|
* @path: path to the block device to open
|
|
* @mode: open mode (BLK_OPEN_*)
|
|
* @holder: exclusive holder identifier
|
|
* @hops: holder operations
|
|
*
|
|
* Open the block device described by the device file at @path. If @holder is
|
|
* not %NULL, the block device is opened with exclusive access. Exclusive opens
|
|
* may nest for the same @holder.
|
|
*
|
|
* CONTEXT:
|
|
* Might sleep.
|
|
*
|
|
* RETURNS:
|
|
* Reference to the block_device on success, ERR_PTR(-errno) on failure.
|
|
*/
|
|
struct block_device *blkdev_get_by_path(const char *path, blk_mode_t mode,
|
|
void *holder, const struct blk_holder_ops *hops)
|
|
{
|
|
struct block_device *bdev;
|
|
dev_t dev;
|
|
int error;
|
|
|
|
error = lookup_bdev(path, &dev);
|
|
if (error)
|
|
return ERR_PTR(error);
|
|
|
|
bdev = blkdev_get_by_dev(dev, mode, holder, hops);
|
|
if (!IS_ERR(bdev) && (mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
|
|
blkdev_put(bdev, holder);
|
|
return ERR_PTR(-EACCES);
|
|
}
|
|
|
|
return bdev;
|
|
}
|
|
EXPORT_SYMBOL(blkdev_get_by_path);
|
|
|
|
void blkdev_put(struct block_device *bdev, void *holder)
|
|
{
|
|
struct gendisk *disk = bdev->bd_disk;
|
|
|
|
/*
|
|
* Sync early if it looks like we're the last one. If someone else
|
|
* opens the block device between now and the decrement of bd_openers
|
|
* then we did a sync that we didn't need to, but that's not the end
|
|
* of the world and we want to avoid long (could be several minute)
|
|
* syncs while holding the mutex.
|
|
*/
|
|
if (atomic_read(&bdev->bd_openers) == 1)
|
|
sync_blockdev(bdev);
|
|
|
|
mutex_lock(&disk->open_mutex);
|
|
if (holder)
|
|
bd_end_claim(bdev, holder);
|
|
|
|
/*
|
|
* 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(disk, DISK_EVENT_MEDIA_CHANGE);
|
|
|
|
if (bdev_is_partition(bdev))
|
|
blkdev_put_part(bdev);
|
|
else
|
|
blkdev_put_whole(bdev);
|
|
mutex_unlock(&disk->open_mutex);
|
|
|
|
module_put(disk->fops->owner);
|
|
blkdev_put_no_open(bdev);
|
|
}
|
|
EXPORT_SYMBOL(blkdev_put);
|
|
|
|
/**
|
|
* lookup_bdev() - Look up a struct block_device by name.
|
|
* @pathname: Name of the block device in the filesystem.
|
|
* @dev: Pointer to the block device's dev_t, if found.
|
|
*
|
|
* Lookup the block device's dev_t at @pathname in the current
|
|
* namespace if possible and return it in @dev.
|
|
*
|
|
* Context: May sleep.
|
|
* Return: 0 if succeeded, negative errno otherwise.
|
|
*/
|
|
int lookup_bdev(const char *pathname, dev_t *dev)
|
|
{
|
|
struct inode *inode;
|
|
struct path path;
|
|
int error;
|
|
|
|
if (!pathname || !*pathname)
|
|
return -EINVAL;
|
|
|
|
error = kern_path(pathname, LOOKUP_FOLLOW, &path);
|
|
if (error)
|
|
return error;
|
|
|
|
inode = d_backing_inode(path.dentry);
|
|
error = -ENOTBLK;
|
|
if (!S_ISBLK(inode->i_mode))
|
|
goto out_path_put;
|
|
error = -EACCES;
|
|
if (!may_open_dev(&path))
|
|
goto out_path_put;
|
|
|
|
*dev = inode->i_rdev;
|
|
error = 0;
|
|
out_path_put:
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL(lookup_bdev);
|
|
|
|
/**
|
|
* bdev_mark_dead - mark a block device as dead
|
|
* @bdev: block device to operate on
|
|
* @surprise: indicate a surprise removal
|
|
*
|
|
* Tell the file system that this devices or media is dead. If @surprise is set
|
|
* to %true the device or media is already gone, if not we are preparing for an
|
|
* orderly removal.
|
|
*
|
|
* This calls into the file system, which then typicall syncs out all dirty data
|
|
* and writes back inodes and then invalidates any cached data in the inodes on
|
|
* the file system. In addition we also invalidate the block device mapping.
|
|
*/
|
|
void bdev_mark_dead(struct block_device *bdev, bool surprise)
|
|
{
|
|
mutex_lock(&bdev->bd_holder_lock);
|
|
if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead)
|
|
bdev->bd_holder_ops->mark_dead(bdev, surprise);
|
|
else
|
|
sync_blockdev(bdev);
|
|
mutex_unlock(&bdev->bd_holder_lock);
|
|
|
|
invalidate_bdev(bdev);
|
|
}
|
|
#ifdef CONFIG_DASD_MODULE
|
|
/*
|
|
* Drivers should not use this directly, but the DASD driver has historically
|
|
* had a shutdown to offline mode that doesn't actually remove the gendisk
|
|
* that otherwise looks a lot like a safe device removal.
|
|
*/
|
|
EXPORT_SYMBOL_GPL(bdev_mark_dead);
|
|
#endif
|
|
|
|
void sync_bdevs(bool wait)
|
|
{
|
|
struct inode *inode, *old_inode = NULL;
|
|
|
|
spin_lock(&blockdev_superblock->s_inode_list_lock);
|
|
list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct block_device *bdev;
|
|
|
|
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(&blockdev_superblock->s_inode_list_lock);
|
|
/*
|
|
* We hold a reference to 'inode' so it couldn't have been
|
|
* removed from s_inodes list while we dropped the
|
|
* s_inode_list_lock We cannot iput the inode now as we can
|
|
* be holding the last reference and we cannot iput it under
|
|
* s_inode_list_lock. So we keep the reference and iput it
|
|
* later.
|
|
*/
|
|
iput(old_inode);
|
|
old_inode = inode;
|
|
bdev = I_BDEV(inode);
|
|
|
|
mutex_lock(&bdev->bd_disk->open_mutex);
|
|
if (!atomic_read(&bdev->bd_openers)) {
|
|
; /* skip */
|
|
} else if (wait) {
|
|
/*
|
|
* We keep the error status of individual mapping so
|
|
* that applications can catch the writeback error using
|
|
* fsync(2). See filemap_fdatawait_keep_errors() for
|
|
* details.
|
|
*/
|
|
filemap_fdatawait_keep_errors(inode->i_mapping);
|
|
} else {
|
|
filemap_fdatawrite(inode->i_mapping);
|
|
}
|
|
mutex_unlock(&bdev->bd_disk->open_mutex);
|
|
|
|
spin_lock(&blockdev_superblock->s_inode_list_lock);
|
|
}
|
|
spin_unlock(&blockdev_superblock->s_inode_list_lock);
|
|
iput(old_inode);
|
|
}
|
|
|
|
/*
|
|
* Handle STATX_DIOALIGN for block devices.
|
|
*
|
|
* Note that the inode passed to this is the inode of a block device node file,
|
|
* not the block device's internal inode. Therefore it is *not* valid to use
|
|
* I_BDEV() here; the block device has to be looked up by i_rdev instead.
|
|
*/
|
|
void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
|
|
{
|
|
struct block_device *bdev;
|
|
|
|
bdev = blkdev_get_no_open(inode->i_rdev);
|
|
if (!bdev)
|
|
return;
|
|
|
|
stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
|
|
stat->dio_offset_align = bdev_logical_block_size(bdev);
|
|
stat->result_mask |= STATX_DIOALIGN;
|
|
|
|
blkdev_put_no_open(bdev);
|
|
}
|