| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
| * Copyright (C) 2016 - 2020 Christoph Hellwig |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/kmod.h> |
| #include <linux/major.h> |
| #include <linux/device_cgroup.h> |
| #include <linux/blkdev.h> |
| #include <linux/blk-integrity.h> |
| #include <linux/backing-dev.h> |
| #include <linux/module.h> |
| #include <linux/blkpg.h> |
| #include <linux/magic.h> |
| #include <linux/buffer_head.h> |
| #include <linux/swap.h> |
| #include <linux/writeback.h> |
| #include <linux/mount.h> |
| #include <linux/pseudo_fs.h> |
| #include <linux/uio.h> |
| #include <linux/namei.h> |
| #include <linux/part_stat.h> |
| #include <linux/uaccess.h> |
| #include <linux/stat.h> |
| #include "../fs/internal.h" |
| #include "blk.h" |
| |
| struct bdev_inode { |
| struct block_device bdev; |
| struct inode vfs_inode; |
| }; |
| |
| static inline struct bdev_inode *BDEV_I(struct inode *inode) |
| { |
| return container_of(inode, struct bdev_inode, vfs_inode); |
| } |
| |
| struct block_device *I_BDEV(struct inode *inode) |
| { |
| return &BDEV_I(inode)->bdev; |
| } |
| EXPORT_SYMBOL(I_BDEV); |
| |
| static void bdev_write_inode(struct block_device *bdev) |
| { |
| struct inode *inode = bdev->bd_inode; |
| int ret; |
| |
| spin_lock(&inode->i_lock); |
| while (inode->i_state & I_DIRTY) { |
| spin_unlock(&inode->i_lock); |
| ret = write_inode_now(inode, true); |
| if (ret) |
| pr_warn_ratelimited( |
| "VFS: Dirty inode writeback failed for block device %pg (err=%d).\n", |
| bdev, ret); |
| spin_lock(&inode->i_lock); |
| } |
| spin_unlock(&inode->i_lock); |
| } |
| |
| /* Kill _all_ buffers and pagecache , dirty or not.. */ |
| static void kill_bdev(struct block_device *bdev) |
| { |
| struct address_space *mapping = bdev->bd_inode->i_mapping; |
| |
| if (mapping_empty(mapping)) |
| return; |
| |
| invalidate_bh_lrus(); |
| truncate_inode_pages(mapping, 0); |
| } |
| |
| /* Invalidate clean unused buffers and pagecache. */ |
| void invalidate_bdev(struct block_device *bdev) |
| { |
| struct address_space *mapping = bdev->bd_inode->i_mapping; |
| |
| if (mapping->nrpages) { |
| invalidate_bh_lrus(); |
| lru_add_drain_all(); /* make sure all lru add caches are flushed */ |
| invalidate_mapping_pages(mapping, 0, -1); |
| } |
| } |
| EXPORT_SYMBOL(invalidate_bdev); |
| |
| /* |
| * Drop all buffers & page cache for given bdev range. This function bails |
| * with error if bdev has other exclusive owner (such as filesystem). |
| */ |
| int truncate_bdev_range(struct block_device *bdev, fmode_t mode, |
| loff_t lstart, loff_t lend) |
| { |
| /* |
| * If we don't hold exclusive handle for the device, upgrade to it |
| * while we discard the buffer cache to avoid discarding buffers |
| * under live filesystem. |
| */ |
| if (!(mode & FMODE_EXCL)) { |
| int err = bd_prepare_to_claim(bdev, truncate_bdev_range); |
| if (err) |
| goto invalidate; |
| } |
| |
| truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); |
| if (!(mode & FMODE_EXCL)) |
| bd_abort_claiming(bdev, truncate_bdev_range); |
| return 0; |
| |
| invalidate: |
| /* |
| * Someone else has handle exclusively open. Try invalidating instead. |
| * The 'end' argument is inclusive so the rounding is safe. |
| */ |
| return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, |
| lstart >> PAGE_SHIFT, |
| lend >> PAGE_SHIFT); |
| } |
| |
| static void set_init_blocksize(struct block_device *bdev) |
| { |
| unsigned int bsize = bdev_logical_block_size(bdev); |
| loff_t size = i_size_read(bdev->bd_inode); |
| |
| while (bsize < PAGE_SIZE) { |
| if (size & bsize) |
| break; |
| bsize <<= 1; |
| } |
| bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
| } |
| |
| int set_blocksize(struct block_device *bdev, int size) |
| { |
| /* Size must be a power of two, and between 512 and PAGE_SIZE */ |
| if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
| return -EINVAL; |
| |
| /* Size cannot be smaller than the size supported by the device */ |
| if (size < bdev_logical_block_size(bdev)) |
| return -EINVAL; |
| |
| /* Don't change the size if it is same as current */ |
| if (bdev->bd_inode->i_blkbits != blksize_bits(size)) { |
| sync_blockdev(bdev); |
| bdev->bd_inode->i_blkbits = blksize_bits(size); |
| kill_bdev(bdev); |
| } |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(set_blocksize); |
| |
| int sb_set_blocksize(struct super_block *sb, int size) |
| { |
| if (set_blocksize(sb->s_bdev, size)) |
| return 0; |
| /* If we get here, we know size is power of two |
| * and it's value is between 512 and PAGE_SIZE */ |
| sb->s_blocksize = size; |
| sb->s_blocksize_bits = blksize_bits(size); |
| return sb->s_blocksize; |
| } |
| |
| EXPORT_SYMBOL(sb_set_blocksize); |
| |
| int sb_min_blocksize(struct super_block *sb, int size) |
| { |
| int minsize = bdev_logical_block_size(sb->s_bdev); |
| if (size < minsize) |
| size = minsize; |
| return sb_set_blocksize(sb, size); |
| } |
| |
| EXPORT_SYMBOL(sb_min_blocksize); |
| |
| int sync_blockdev_nowait(struct block_device *bdev) |
| { |
| if (!bdev) |
| return 0; |
| return filemap_flush(bdev->bd_inode->i_mapping); |
| } |
| EXPORT_SYMBOL_GPL(sync_blockdev_nowait); |
| |
| /* |
| * Write out and wait upon all the dirty data associated with a block |
| * device via its mapping. Does not take the superblock lock. |
| */ |
| int sync_blockdev(struct block_device *bdev) |
| { |
| if (!bdev) |
| return 0; |
| return filemap_write_and_wait(bdev->bd_inode->i_mapping); |
| } |
| EXPORT_SYMBOL(sync_blockdev); |
| |
| int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend) |
| { |
| return filemap_write_and_wait_range(bdev->bd_inode->i_mapping, |
| lstart, lend); |
| } |
| EXPORT_SYMBOL(sync_blockdev_range); |
| |
| /* |
| * Write out and wait upon all dirty data associated with this |
| * device. Filesystem data as well as the underlying block |
| * device. Takes the superblock lock. |
| */ |
| int fsync_bdev(struct block_device *bdev) |
| { |
| struct super_block *sb = get_super(bdev); |
| if (sb) { |
| int res = sync_filesystem(sb); |
| drop_super(sb); |
| return res; |
| } |
| return sync_blockdev(bdev); |
| } |
| EXPORT_SYMBOL(fsync_bdev); |
| |
| /** |
| * freeze_bdev -- lock a filesystem and force it into a consistent state |
| * @bdev: blockdevice to lock |
| * |
| * If a superblock is found on this device, we take the s_umount semaphore |
| * on it to make sure nobody unmounts until the snapshot creation is done. |
| * The reference counter (bd_fsfreeze_count) guarantees that only the last |
| * unfreeze process can unfreeze the frozen filesystem actually when multiple |
| * freeze requests arrive simultaneously. It counts up in freeze_bdev() and |
| * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze |
| * actually. |
| */ |
| int freeze_bdev(struct block_device *bdev) |
| { |
| struct super_block *sb; |
| int error = 0; |
| |
| mutex_lock(&bdev->bd_fsfreeze_mutex); |
| if (++bdev->bd_fsfreeze_count > 1) |
| goto done; |
| |
| sb = get_active_super(bdev); |
| if (!sb) |
| goto sync; |
| if (sb->s_op->freeze_super) |
| error = sb->s_op->freeze_super(sb); |
| else |
| error = freeze_super(sb); |
| deactivate_super(sb); |
| |
| if (error) { |
| bdev->bd_fsfreeze_count--; |
| goto done; |
| } |
| bdev->bd_fsfreeze_sb = sb; |
| |
| sync: |
| sync_blockdev(bdev); |
| done: |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL(freeze_bdev); |
| |
| /** |
| * thaw_bdev -- unlock filesystem |
| * @bdev: blockdevice to unlock |
| * |
| * Unlocks the filesystem and marks it writeable again after freeze_bdev(). |
| */ |
| int thaw_bdev(struct block_device *bdev) |
| { |
| struct super_block *sb; |
| int error = -EINVAL; |
| |
| mutex_lock(&bdev->bd_fsfreeze_mutex); |
| if (!bdev->bd_fsfreeze_count) |
| goto out; |
| |
| error = 0; |
| if (--bdev->bd_fsfreeze_count > 0) |
| goto out; |
| |
| sb = bdev->bd_fsfreeze_sb; |
| if (!sb) |
| goto out; |
| |
| if (sb->s_op->thaw_super) |
| error = sb->s_op->thaw_super(sb); |
| else |
| error = thaw_super(sb); |
| if (error) |
| bdev->bd_fsfreeze_count++; |
| else |
| bdev->bd_fsfreeze_sb = NULL; |
| out: |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL(thaw_bdev); |
| |
| /** |
| * bdev_read_page() - Start reading a page from a block device |
| * @bdev: The device to read the page from |
| * @sector: The offset on the device to read the page to (need not be aligned) |
| * @page: The page to read |
| * |
| * On entry, the page should be locked. It will be unlocked when the page |
| * has been read. If the block driver implements rw_page synchronously, |
| * that will be true on exit from this function, but it need not be. |
| * |
| * Errors returned by this function are usually "soft", eg out of memory, or |
| * queue full; callers should try a different route to read this page rather |
| * than propagate an error back up the stack. |
| * |
| * Return: negative errno if an error occurs, 0 if submission was successful. |
| */ |
| int bdev_read_page(struct block_device *bdev, sector_t sector, |
| struct page *page) |
| { |
| const struct block_device_operations *ops = bdev->bd_disk->fops; |
| int result = -EOPNOTSUPP; |
| |
| if (!ops->rw_page || bdev_get_integrity(bdev)) |
| return result; |
| |
| result = blk_queue_enter(bdev_get_queue(bdev), 0); |
| if (result) |
| return result; |
| result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, |
| REQ_OP_READ); |
| blk_queue_exit(bdev_get_queue(bdev)); |
| return result; |
| } |
| |
| /** |
| * bdev_write_page() - Start writing a page to a block device |
| * @bdev: The device to write the page to |
| * @sector: The offset on the device to write the page to (need not be aligned) |
| * @page: The page to write |
| * @wbc: The writeback_control for the write |
| * |
| * On entry, the page should be locked and not currently under writeback. |
| * On exit, if the write started successfully, the page will be unlocked and |
| * under writeback. If the write failed already (eg the driver failed to |
| * queue the page to the device), the page will still be locked. If the |
| * caller is a ->writepage implementation, it will need to unlock the page. |
| * |
| * Errors returned by this function are usually "soft", eg out of memory, or |
| * queue full; callers should try a different route to write this page rather |
| * than propagate an error back up the stack. |
| * |
| * Return: negative errno if an error occurs, 0 if submission was successful. |
| */ |
| int bdev_write_page(struct block_device *bdev, sector_t sector, |
| struct page *page, struct writeback_control *wbc) |
| { |
| int result; |
| const struct block_device_operations *ops = bdev->bd_disk->fops; |
| |
| if (!ops->rw_page || bdev_get_integrity(bdev)) |
| return -EOPNOTSUPP; |
| result = blk_queue_enter(bdev_get_queue(bdev), 0); |
| if (result) |
| return result; |
| |
| set_page_writeback(page); |
| result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, |
| REQ_OP_WRITE); |
| if (result) { |
| end_page_writeback(page); |
| } else { |
| clean_page_buffers(page); |
| unlock_page(page); |
| } |
| blk_queue_exit(bdev_get_queue(bdev)); |
| return result; |
| } |
| |
| /* |
| * pseudo-fs |
| */ |
| |
| static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
| static struct kmem_cache * bdev_cachep __read_mostly; |
| |
| static struct inode *bdev_alloc_inode(struct super_block *sb) |
| { |
| struct bdev_inode *ei = alloc_inode_sb(sb, bdev_cachep, GFP_KERNEL); |
| |
| if (!ei) |
| return NULL; |
| memset(&ei->bdev, 0, sizeof(ei->bdev)); |
| return &ei->vfs_inode; |
| } |
| |
| static void bdev_free_inode(struct inode *inode) |
| { |
| struct block_device *bdev = I_BDEV(inode); |
| |
| free_percpu(bdev->bd_stats); |
| kfree(bdev->bd_meta_info); |
| |
| if (!bdev_is_partition(bdev)) { |
| if (bdev->bd_disk && bdev->bd_disk->bdi) |
| bdi_put(bdev->bd_disk->bdi); |
| kfree(bdev->bd_disk); |
| } |
| |
| if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR) |
| blk_free_ext_minor(MINOR(bdev->bd_dev)); |
| |
| kmem_cache_free(bdev_cachep, BDEV_I(inode)); |
| } |
| |
| static void init_once(void *data) |
| { |
| struct bdev_inode *ei = data; |
| |
| inode_init_once(&ei->vfs_inode); |
| } |
| |
| static void bdev_evict_inode(struct inode *inode) |
| { |
| truncate_inode_pages_final(&inode->i_data); |
| invalidate_inode_buffers(inode); /* is it needed here? */ |
| clear_inode(inode); |
| } |
| |
| static const struct super_operations bdev_sops = { |
| .statfs = simple_statfs, |
| .alloc_inode = bdev_alloc_inode, |
| .free_inode = bdev_free_inode, |
| .drop_inode = generic_delete_inode, |
| .evict_inode = bdev_evict_inode, |
| }; |
| |
| static int bd_init_fs_context(struct fs_context *fc) |
| { |
| struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); |
| if (!ctx) |
| return -ENOMEM; |
| fc->s_iflags |= SB_I_CGROUPWB; |
| ctx->ops = &bdev_sops; |
| return 0; |
| } |
| |
| static struct file_system_type bd_type = { |
| .name = "bdev", |
| .init_fs_context = bd_init_fs_context, |
| .kill_sb = kill_anon_super, |
| }; |
| |
| struct super_block *blockdev_superblock __read_mostly; |
| EXPORT_SYMBOL_GPL(blockdev_superblock); |
| |
| void __init bdev_cache_init(void) |
| { |
| int err; |
| static struct vfsmount *bd_mnt; |
| |
| bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
| 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
| SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), |
| init_once); |
| err = register_filesystem(&bd_type); |
| if (err) |
| panic("Cannot register bdev pseudo-fs"); |
| bd_mnt = kern_mount(&bd_type); |
| if (IS_ERR(bd_mnt)) |
| panic("Cannot create bdev pseudo-fs"); |
| blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
| } |
| |
| struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) |
| { |
| struct block_device *bdev; |
| struct inode *inode; |
| |
| inode = new_inode(blockdev_superblock); |
| if (!inode) |
| return NULL; |
| inode->i_mode = S_IFBLK; |
| inode->i_rdev = 0; |
| inode->i_data.a_ops = &def_blk_aops; |
| mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
| |
| bdev = I_BDEV(inode); |
| mutex_init(&bdev->bd_fsfreeze_mutex); |
| spin_lock_init(&bdev->bd_size_lock); |
| bdev->bd_partno = partno; |
| bdev->bd_inode = inode; |
| bdev->bd_queue = disk->queue; |
| bdev->bd_stats = alloc_percpu(struct disk_stats); |
| if (!bdev->bd_stats) { |
| iput(inode); |
| return NULL; |
| } |
| bdev->bd_disk = disk; |
| return bdev; |
| } |
| |
| void bdev_add(struct block_device *bdev, dev_t dev) |
| { |
| bdev->bd_dev = dev; |
| bdev->bd_inode->i_rdev = dev; |
| bdev->bd_inode->i_ino = dev; |
| insert_inode_hash(bdev->bd_inode); |
| } |
| |
| long nr_blockdev_pages(void) |
| { |
| struct inode *inode; |
| long ret = 0; |
| |
| spin_lock(&blockdev_superblock->s_inode_list_lock); |
| list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) |
| ret += inode->i_mapping->nrpages; |
| spin_unlock(&blockdev_superblock->s_inode_list_lock); |
| |
| return ret; |
| } |
| |
| /** |
| * bd_may_claim - test whether a block device can be claimed |
| * @bdev: block device of interest |
| * @whole: whole block device containing @bdev, may equal @bdev |
| * @holder: holder trying to claim @bdev |
| * |
| * Test whether @bdev can be claimed by @holder. |
| * |
| * CONTEXT: |
| * spin_lock(&bdev_lock). |
| * |
| * RETURNS: |
| * %true if @bdev can be claimed, %false otherwise. |
| */ |
| static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, |
| void *holder) |
| { |
| if (bdev->bd_holder == holder) |
| return true; /* already a holder */ |
| else if (bdev->bd_holder != NULL) |
| return false; /* held by someone else */ |
| else if (whole == bdev) |
| return true; /* is a whole device which isn't held */ |
| |
| else if (whole->bd_holder == bd_may_claim) |
| return true; /* is a partition of a device that is being partitioned */ |
| else if (whole->bd_holder != NULL) |
| return false; /* is a partition of a held device */ |
| else |
| return true; /* is a partition of an un-held device */ |
| } |
| |
| /** |
| * bd_prepare_to_claim - claim a block device |
| * @bdev: block device of interest |
| * @holder: holder trying to claim @bdev |
| * |
| * Claim @bdev. This function fails if @bdev is already claimed by another |
| * holder and waits if another claiming is in progress. return, the caller |
| * has ownership of bd_claiming and bd_holder[s]. |
| * |
| * RETURNS: |
| * 0 if @bdev can be claimed, -EBUSY otherwise. |
| */ |
| int bd_prepare_to_claim(struct block_device *bdev, void *holder) |
| { |
| struct block_device *whole = bdev_whole(bdev); |
| |
| if (WARN_ON_ONCE(!holder)) |
| return -EINVAL; |
| retry: |
| spin_lock(&bdev_lock); |
| /* if someone else claimed, fail */ |
| if (!bd_may_claim(bdev, whole, holder)) { |
| spin_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); |
| spin_unlock(&bdev_lock); |
| schedule(); |
| finish_wait(wq, &wait); |
| goto retry; |
| } |
| |
| /* yay, all mine */ |
| whole->bd_claiming = holder; |
| spin_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 |
| * |
| * 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) |
| { |
| struct block_device *whole = bdev_whole(bdev); |
| |
| spin_lock(&bdev_lock); |
| BUG_ON(!bd_may_claim(bdev, whole, holder)); |
| /* |
| * Note that for a whole device bd_holders will be incremented twice, |
| * and bd_holder will be set to bd_may_claim before being set to holder |
| */ |
| whole->bd_holders++; |
| whole->bd_holder = bd_may_claim; |
| bdev->bd_holders++; |
| bdev->bd_holder = holder; |
| bd_clear_claiming(whole, holder); |
| spin_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) |
| { |
| spin_lock(&bdev_lock); |
| bd_clear_claiming(bdev_whole(bdev), holder); |
| spin_unlock(&bdev_lock); |
| } |
| EXPORT_SYMBOL(bd_abort_claiming); |
| |
| 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, fmode_t mode) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| int ret; |
| |
| if (disk->fops->open) { |
| ret = disk->fops->open(bdev, 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, fmode_t mode) |
| { |
| 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, mode); |
| } |
| |
| static int blkdev_get_part(struct block_device *part, fmode_t mode) |
| { |
| struct gendisk *disk = part->bd_disk; |
| int ret; |
| |
| if (atomic_read(&part->bd_openers)) |
| goto done; |
| |
| ret = blkdev_get_whole(bdev_whole(part), mode); |
| if (ret) |
| return ret; |
| |
| ret = -ENXIO; |
| if (!bdev_nr_sectors(part)) |
| goto out_blkdev_put; |
| |
| disk->open_partitions++; |
| set_init_blocksize(part); |
| done: |
| atomic_inc(&part->bd_openers); |
| return 0; |
| |
| out_blkdev_put: |
| blkdev_put_whole(bdev_whole(part), mode); |
| return ret; |
| } |
| |
| static void blkdev_put_part(struct block_device *part, fmode_t mode) |
| { |
| struct block_device *whole = bdev_whole(part); |
| |
| if (!atomic_dec_and_test(&part->bd_openers)) |
| return; |
| blkdev_flush_mapping(part); |
| whole->bd_disk->open_partitions--; |
| blkdev_put_whole(whole, mode); |
| } |
| |
| 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: FMODE_* mask |
| * @holder: exclusive holder identifier |
| * |
| * Open the block device described by device number @dev. If @mode includes |
| * %FMODE_EXCL, the block device is opened with exclusive access. Specifying |
| * %FMODE_EXCL with a %NULL @holder is invalid. 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, fmode_t mode, void *holder) |
| { |
| 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 & FMODE_READ) ? DEVCG_ACC_READ : 0) | |
| ((mode & FMODE_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 (mode & FMODE_EXCL) { |
| ret = bd_prepare_to_claim(bdev, holder); |
| if (ret) |
| 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 (mode & FMODE_EXCL) { |
| bd_finish_claiming(bdev, holder); |
| |
| /* |
| * 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 & FMODE_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 (mode & FMODE_EXCL) |
| 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: FMODE_* mask |
| * @holder: exclusive holder identifier |
| * |
| * Open the block device described by the device file at @path. If @mode |
| * includes %FMODE_EXCL, the block device is opened with exclusive access. |
| * Specifying %FMODE_EXCL with a %NULL @holder is invalid. 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, fmode_t mode, |
| void *holder) |
| { |
| 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); |
| if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
| blkdev_put(bdev, mode); |
| return ERR_PTR(-EACCES); |
| } |
| |
| return bdev; |
| } |
| EXPORT_SYMBOL(blkdev_get_by_path); |
| |
| void blkdev_put(struct block_device *bdev, fmode_t mode) |
| { |
| 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 (mode & FMODE_EXCL) { |
| struct block_device *whole = bdev_whole(bdev); |
| bool bdev_free; |
| |
| /* |
| * Release a claim on the device. The holder fields |
| * are protected with bdev_lock. open_mutex is to |
| * synchronize disk_holder unlinking. |
| */ |
| spin_lock(&bdev_lock); |
| |
| WARN_ON_ONCE(--bdev->bd_holders < 0); |
| WARN_ON_ONCE(--whole->bd_holders < 0); |
| |
| if ((bdev_free = !bdev->bd_holders)) |
| bdev->bd_holder = NULL; |
| if (!whole->bd_holders) |
| whole->bd_holder = NULL; |
| |
| spin_unlock(&bdev_lock); |
| |
| /* |
| * If this was the last claim, remove holder link and |
| * unblock evpoll if it was a write holder. |
| */ |
| if (bdev_free && bdev->bd_write_holder) { |
| disk_unblock_events(disk); |
| bdev->bd_write_holder = false; |
| } |
| } |
| |
| /* |
| * Trigger event checking and tell drivers to flush MEDIA_CHANGE |
| * event. This is to ensure detection of media removal commanded |
| * from userland - e.g. eject(1). |
| */ |
| disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); |
| |
| if (bdev_is_partition(bdev)) |
| blkdev_put_part(bdev, mode); |
| else |
| blkdev_put_whole(bdev, mode); |
| 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); |
| |
| int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
| { |
| struct super_block *sb = get_super(bdev); |
| int res = 0; |
| |
| if (sb) { |
| /* |
| * no need to lock the super, get_super holds the |
| * read mutex so the filesystem cannot go away |
| * under us (->put_super runs with the write lock |
| * hold). |
| */ |
| shrink_dcache_sb(sb); |
| res = invalidate_inodes(sb, kill_dirty); |
| drop_super(sb); |
| } |
| invalidate_bdev(bdev); |
| return res; |
| } |
| EXPORT_SYMBOL(__invalidate_device); |
| |
| void 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); |
| } |