| /* |
| * linux/fs/block_dev.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/fcntl.h> |
| #include <linux/slab.h> |
| #include <linux/kmod.h> |
| #include <linux/major.h> |
| #include <linux/device_cgroup.h> |
| #include <linux/highmem.h> |
| #include <linux/blkdev.h> |
| #include <linux/module.h> |
| #include <linux/blkpg.h> |
| #include <linux/buffer_head.h> |
| #include <linux/pagevec.h> |
| #include <linux/writeback.h> |
| #include <linux/mpage.h> |
| #include <linux/mount.h> |
| #include <linux/uio.h> |
| #include <linux/namei.h> |
| #include <linux/log2.h> |
| #include <linux/kmemleak.h> |
| #include <asm/uaccess.h> |
| #include "internal.h" |
| |
| struct bdev_inode { |
| struct block_device bdev; |
| struct inode vfs_inode; |
| }; |
| |
| static const struct address_space_operations def_blk_aops; |
| |
| static inline struct bdev_inode *BDEV_I(struct inode *inode) |
| { |
| return container_of(inode, struct bdev_inode, vfs_inode); |
| } |
| |
| inline struct block_device *I_BDEV(struct inode *inode) |
| { |
| return &BDEV_I(inode)->bdev; |
| } |
| EXPORT_SYMBOL(I_BDEV); |
| |
| /* |
| * Move the inode from its current bdi to a new bdi. If the inode is dirty we |
| * need to move it onto the dirty list of @dst so that the inode is always on |
| * the right list. |
| */ |
| static void bdev_inode_switch_bdi(struct inode *inode, |
| struct backing_dev_info *dst) |
| { |
| struct backing_dev_info *old = inode->i_data.backing_dev_info; |
| |
| if (unlikely(dst == old)) /* deadlock avoidance */ |
| return; |
| bdi_lock_two(&old->wb, &dst->wb); |
| spin_lock(&inode->i_lock); |
| inode->i_data.backing_dev_info = dst; |
| if (inode->i_state & I_DIRTY) |
| list_move(&inode->i_wb_list, &dst->wb.b_dirty); |
| spin_unlock(&inode->i_lock); |
| spin_unlock(&old->wb.list_lock); |
| spin_unlock(&dst->wb.list_lock); |
| } |
| |
| static sector_t max_block(struct block_device *bdev) |
| { |
| sector_t retval = ~((sector_t)0); |
| loff_t sz = i_size_read(bdev->bd_inode); |
| |
| if (sz) { |
| unsigned int size = block_size(bdev); |
| unsigned int sizebits = blksize_bits(size); |
| retval = (sz >> sizebits); |
| } |
| return retval; |
| } |
| |
| /* Kill _all_ buffers and pagecache , dirty or not.. */ |
| static void kill_bdev(struct block_device *bdev) |
| { |
| if (bdev->bd_inode->i_mapping->nrpages == 0) |
| return; |
| invalidate_bh_lrus(); |
| truncate_inode_pages(bdev->bd_inode->i_mapping, 0); |
| } |
| |
| 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_block_size != size) { |
| sync_blockdev(bdev); |
| bdev->bd_block_size = size; |
| 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); |
| |
| static int |
| blkdev_get_block(struct inode *inode, sector_t iblock, |
| struct buffer_head *bh, int create) |
| { |
| if (iblock >= max_block(I_BDEV(inode))) { |
| if (create) |
| return -EIO; |
| |
| /* |
| * for reads, we're just trying to fill a partial page. |
| * return a hole, they will have to call get_block again |
| * before they can fill it, and they will get -EIO at that |
| * time |
| */ |
| return 0; |
| } |
| bh->b_bdev = I_BDEV(inode); |
| bh->b_blocknr = iblock; |
| set_buffer_mapped(bh); |
| return 0; |
| } |
| |
| static int |
| blkdev_get_blocks(struct inode *inode, sector_t iblock, |
| struct buffer_head *bh, int create) |
| { |
| sector_t end_block = max_block(I_BDEV(inode)); |
| unsigned long max_blocks = bh->b_size >> inode->i_blkbits; |
| |
| if ((iblock + max_blocks) > end_block) { |
| max_blocks = end_block - iblock; |
| if ((long)max_blocks <= 0) { |
| if (create) |
| return -EIO; /* write fully beyond EOF */ |
| /* |
| * It is a read which is fully beyond EOF. We return |
| * a !buffer_mapped buffer |
| */ |
| max_blocks = 0; |
| } |
| } |
| |
| bh->b_bdev = I_BDEV(inode); |
| bh->b_blocknr = iblock; |
| bh->b_size = max_blocks << inode->i_blkbits; |
| if (max_blocks) |
| set_buffer_mapped(bh); |
| return 0; |
| } |
| |
| static ssize_t |
| blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, |
| loff_t offset, unsigned long nr_segs) |
| { |
| struct file *file = iocb->ki_filp; |
| struct inode *inode = file->f_mapping->host; |
| |
| return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset, |
| nr_segs, blkdev_get_blocks, NULL, NULL, 0); |
| } |
| |
| int __sync_blockdev(struct block_device *bdev, int wait) |
| { |
| if (!bdev) |
| return 0; |
| if (!wait) |
| return filemap_flush(bdev->bd_inode->i_mapping); |
| return filemap_write_and_wait(bdev->bd_inode->i_mapping); |
| } |
| |
| /* |
| * 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) |
| { |
| return __sync_blockdev(bdev, 1); |
| } |
| EXPORT_SYMBOL(sync_blockdev); |
| |
| /* |
| * 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. |
| */ |
| struct super_block *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) { |
| /* |
| * We don't even need to grab a reference - the first call |
| * to freeze_bdev grab an active reference and only the last |
| * thaw_bdev drops it. |
| */ |
| sb = get_super(bdev); |
| drop_super(sb); |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return sb; |
| } |
| |
| sb = get_active_super(bdev); |
| if (!sb) |
| goto out; |
| error = freeze_super(sb); |
| if (error) { |
| deactivate_super(sb); |
| bdev->bd_fsfreeze_count--; |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return ERR_PTR(error); |
| } |
| deactivate_super(sb); |
| out: |
| sync_blockdev(bdev); |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return sb; /* thaw_bdev releases s->s_umount */ |
| } |
| EXPORT_SYMBOL(freeze_bdev); |
| |
| /** |
| * thaw_bdev -- unlock filesystem |
| * @bdev: blockdevice to unlock |
| * @sb: associated superblock |
| * |
| * 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; |
| |
| if (!sb) |
| goto out; |
| |
| error = thaw_super(sb); |
| if (error) { |
| bdev->bd_fsfreeze_count++; |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return error; |
| } |
| out: |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return 0; |
| } |
| EXPORT_SYMBOL(thaw_bdev); |
| |
| static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| return block_write_full_page(page, blkdev_get_block, wbc); |
| } |
| |
| static int blkdev_readpage(struct file * file, struct page * page) |
| { |
| return block_read_full_page(page, blkdev_get_block); |
| } |
| |
| static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| return block_write_begin(mapping, pos, len, flags, pagep, |
| blkdev_get_block); |
| } |
| |
| static int blkdev_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| int ret; |
| ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); |
| |
| unlock_page(page); |
| page_cache_release(page); |
| |
| return ret; |
| } |
| |
| /* |
| * private llseek: |
| * for a block special file file->f_path.dentry->d_inode->i_size is zero |
| * so we compute the size by hand (just as in block_read/write above) |
| */ |
| static loff_t block_llseek(struct file *file, loff_t offset, int origin) |
| { |
| struct inode *bd_inode = file->f_mapping->host; |
| loff_t size; |
| loff_t retval; |
| |
| mutex_lock(&bd_inode->i_mutex); |
| size = i_size_read(bd_inode); |
| |
| switch (origin) { |
| case 2: |
| offset += size; |
| break; |
| case 1: |
| offset += file->f_pos; |
| } |
| retval = -EINVAL; |
| if (offset >= 0 && offset <= size) { |
| if (offset != file->f_pos) { |
| file->f_pos = offset; |
| } |
| retval = offset; |
| } |
| mutex_unlock(&bd_inode->i_mutex); |
| return retval; |
| } |
| |
| int blkdev_fsync(struct file *filp, int datasync) |
| { |
| struct inode *bd_inode = filp->f_mapping->host; |
| struct block_device *bdev = I_BDEV(bd_inode); |
| int error; |
| |
| /* |
| * There is no need to serialise calls to blkdev_issue_flush with |
| * i_mutex and doing so causes performance issues with concurrent |
| * O_SYNC writers to a block device. |
| */ |
| mutex_unlock(&bd_inode->i_mutex); |
| |
| error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
| if (error == -EOPNOTSUPP) |
| error = 0; |
| |
| mutex_lock(&bd_inode->i_mutex); |
| |
| return error; |
| } |
| EXPORT_SYMBOL(blkdev_fsync); |
| |
| /* |
| * pseudo-fs |
| */ |
| |
| static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
| static struct kmem_cache * bdev_cachep __read_mostly; |
| |
| static struct inode *bdev_alloc_inode(struct super_block *sb) |
| { |
| struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
| if (!ei) |
| return NULL; |
| return &ei->vfs_inode; |
| } |
| |
| static void bdev_i_callback(struct rcu_head *head) |
| { |
| struct inode *inode = container_of(head, struct inode, i_rcu); |
| struct bdev_inode *bdi = BDEV_I(inode); |
| |
| INIT_LIST_HEAD(&inode->i_dentry); |
| kmem_cache_free(bdev_cachep, bdi); |
| } |
| |
| static void bdev_destroy_inode(struct inode *inode) |
| { |
| call_rcu(&inode->i_rcu, bdev_i_callback); |
| } |
| |
| static void init_once(void *foo) |
| { |
| struct bdev_inode *ei = (struct bdev_inode *) foo; |
| struct block_device *bdev = &ei->bdev; |
| |
| memset(bdev, 0, sizeof(*bdev)); |
| mutex_init(&bdev->bd_mutex); |
| INIT_LIST_HEAD(&bdev->bd_inodes); |
| INIT_LIST_HEAD(&bdev->bd_list); |
| #ifdef CONFIG_SYSFS |
| INIT_LIST_HEAD(&bdev->bd_holder_disks); |
| #endif |
| inode_init_once(&ei->vfs_inode); |
| /* Initialize mutex for freeze. */ |
| mutex_init(&bdev->bd_fsfreeze_mutex); |
| } |
| |
| static inline void __bd_forget(struct inode *inode) |
| { |
| list_del_init(&inode->i_devices); |
| inode->i_bdev = NULL; |
| inode->i_mapping = &inode->i_data; |
| } |
| |
| static void bdev_evict_inode(struct inode *inode) |
| { |
| struct block_device *bdev = &BDEV_I(inode)->bdev; |
| struct list_head *p; |
| truncate_inode_pages(&inode->i_data, 0); |
| invalidate_inode_buffers(inode); /* is it needed here? */ |
| end_writeback(inode); |
| spin_lock(&bdev_lock); |
| while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { |
| __bd_forget(list_entry(p, struct inode, i_devices)); |
| } |
| list_del_init(&bdev->bd_list); |
| spin_unlock(&bdev_lock); |
| } |
| |
| static const struct super_operations bdev_sops = { |
| .statfs = simple_statfs, |
| .alloc_inode = bdev_alloc_inode, |
| .destroy_inode = bdev_destroy_inode, |
| .drop_inode = generic_delete_inode, |
| .evict_inode = bdev_evict_inode, |
| }; |
| |
| static struct dentry *bd_mount(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data) |
| { |
| return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, 0x62646576); |
| } |
| |
| static struct file_system_type bd_type = { |
| .name = "bdev", |
| .mount = bd_mount, |
| .kill_sb = kill_anon_super, |
| }; |
| |
| struct super_block *blockdev_superblock __read_mostly; |
| |
| void __init bdev_cache_init(void) |
| { |
| int err; |
| 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) |
| { |
| ihold(bdev->bd_inode); |
| return bdev; |
| } |
| |
| long nr_blockdev_pages(void) |
| { |
| struct block_device *bdev; |
| long ret = 0; |
| spin_lock(&bdev_lock); |
| list_for_each_entry(bdev, &all_bdevs, bd_list) { |
| ret += bdev->bd_inode->i_mapping->nrpages; |
| } |
| spin_unlock(&bdev_lock); |
| return ret; |
| } |
| |
| void bdput(struct block_device *bdev) |
| { |
| iput(bdev->bd_inode); |
| } |
| |
| EXPORT_SYMBOL(bdput); |
| |
| static struct block_device *bd_acquire(struct inode *inode) |
| { |
| struct block_device *bdev; |
| |
| spin_lock(&bdev_lock); |
| bdev = inode->i_bdev; |
| if (bdev) { |
| ihold(bdev->bd_inode); |
| spin_unlock(&bdev_lock); |
| return bdev; |
| } |
| spin_unlock(&bdev_lock); |
| |
| bdev = bdget(inode->i_rdev); |
| if (bdev) { |
| spin_lock(&bdev_lock); |
| if (!inode->i_bdev) { |
| /* |
| * We take an additional reference to bd_inode, |
| * and it's released in clear_inode() of inode. |
| * So, we can access it via ->i_mapping always |
| * without igrab(). |
| */ |
| ihold(bdev->bd_inode); |
| inode->i_bdev = bdev; |
| inode->i_mapping = bdev->bd_inode->i_mapping; |
| list_add(&inode->i_devices, &bdev->bd_inodes); |
| } |
| spin_unlock(&bdev_lock); |
| } |
| return bdev; |
| } |
| |
| /* Call when you free inode */ |
| |
| void bd_forget(struct inode *inode) |
| { |
| struct block_device *bdev = NULL; |
| |
| spin_lock(&bdev_lock); |
| if (inode->i_bdev) { |
| if (!sb_is_blkdev_sb(inode->i_sb)) |
| bdev = inode->i_bdev; |
| __bd_forget(inode); |
| } |
| spin_unlock(&bdev_lock); |
| |
| if (bdev) |
| iput(bdev->bd_inode); |
| } |
| |
| /** |
| * bd_may_claim - test whether a block device can be claimed |
| * @bdev: block device of interest |
| * @whole: whole block device containing @bdev, may equal @bdev |
| * @holder: holder trying to claim @bdev |
| * |
| * Test whether @bdev can be claimed by @holder. |
| * |
| * CONTEXT: |
| * spin_lock(&bdev_lock). |
| * |
| * RETURNS: |
| * %true if @bdev can be claimed, %false otherwise. |
| */ |
| static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, |
| void *holder) |
| { |
| if (bdev->bd_holder == holder) |
| return true; /* already a holder */ |
| else if (bdev->bd_holder != NULL) |
| return false; /* held by someone else */ |
| else if (bdev->bd_contains == bdev) |
| return true; /* is a whole device which isn't held */ |
| |
| else if (whole->bd_holder == bd_may_claim) |
| return true; /* is a partition of a device that is being partitioned */ |
| else if (whole->bd_holder != NULL) |
| return false; /* is a partition of a held device */ |
| else |
| return true; /* is a partition of an un-held device */ |
| } |
| |
| /** |
| * bd_prepare_to_claim - prepare to claim a block device |
| * @bdev: block device of interest |
| * @whole: the whole device containing @bdev, may equal @bdev |
| * @holder: holder trying to claim @bdev |
| * |
| * Prepare to claim @bdev. This function fails if @bdev is already |
| * claimed by another holder and waits if another claiming is in |
| * progress. This function doesn't actually claim. On successful |
| * return, the caller has ownership of bd_claiming and bd_holder[s]. |
| * |
| * CONTEXT: |
| * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab |
| * it multiple times. |
| * |
| * RETURNS: |
| * 0 if @bdev can be claimed, -EBUSY otherwise. |
| */ |
| static int bd_prepare_to_claim(struct block_device *bdev, |
| struct block_device *whole, void *holder) |
| { |
| retry: |
| /* if someone else claimed, fail */ |
| if (!bd_may_claim(bdev, whole, holder)) |
| return -EBUSY; |
| |
| /* if claiming is already in progress, wait for it to finish */ |
| if (whole->bd_claiming) { |
| wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
| DEFINE_WAIT(wait); |
| |
| prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); |
| spin_unlock(&bdev_lock); |
| schedule(); |
| finish_wait(wq, &wait); |
| spin_lock(&bdev_lock); |
| goto retry; |
| } |
| |
| /* yay, all mine */ |
| return 0; |
| } |
| |
| /** |
| * bd_start_claiming - start claiming a block device |
| * @bdev: block device of interest |
| * @holder: holder trying to claim @bdev |
| * |
| * @bdev is about to be opened exclusively. Check @bdev can be opened |
| * exclusively and mark that an exclusive open is in progress. Each |
| * successful call to this function must be matched with a call to |
| * either bd_finish_claiming() or bd_abort_claiming() (which do not |
| * fail). |
| * |
| * This function is used to gain exclusive access to the block device |
| * without actually causing other exclusive open attempts to fail. It |
| * should be used when the open sequence itself requires exclusive |
| * access but may subsequently fail. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * Pointer to the block device containing @bdev on success, ERR_PTR() |
| * value on failure. |
| */ |
| static struct block_device *bd_start_claiming(struct block_device *bdev, |
| void *holder) |
| { |
| struct gendisk *disk; |
| struct block_device *whole; |
| int partno, err; |
| |
| might_sleep(); |
| |
| /* |
| * @bdev might not have been initialized properly yet, look up |
| * and grab the outer block device the hard way. |
| */ |
| disk = get_gendisk(bdev->bd_dev, &partno); |
| if (!disk) |
| return ERR_PTR(-ENXIO); |
| |
| whole = bdget_disk(disk, 0); |
| module_put(disk->fops->owner); |
| put_disk(disk); |
| if (!whole) |
| return ERR_PTR(-ENOMEM); |
| |
| /* prepare to claim, if successful, mark claiming in progress */ |
| spin_lock(&bdev_lock); |
| |
| err = bd_prepare_to_claim(bdev, whole, holder); |
| if (err == 0) { |
| whole->bd_claiming = holder; |
| spin_unlock(&bdev_lock); |
| return whole; |
| } else { |
| spin_unlock(&bdev_lock); |
| bdput(whole); |
| return ERR_PTR(err); |
| } |
| } |
| |
| #ifdef CONFIG_SYSFS |
| struct bd_holder_disk { |
| struct list_head list; |
| struct gendisk *disk; |
| int refcnt; |
| }; |
| |
| static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, |
| struct gendisk *disk) |
| { |
| struct bd_holder_disk *holder; |
| |
| list_for_each_entry(holder, &bdev->bd_holder_disks, list) |
| if (holder->disk == disk) |
| return holder; |
| return NULL; |
| } |
| |
| static int add_symlink(struct kobject *from, struct kobject *to) |
| { |
| return sysfs_create_link(from, to, kobject_name(to)); |
| } |
| |
| static void del_symlink(struct kobject *from, struct kobject *to) |
| { |
| sysfs_remove_link(from, kobject_name(to)); |
| } |
| |
| /** |
| * bd_link_disk_holder - create symlinks between holding disk and slave bdev |
| * @bdev: the claimed slave bdev |
| * @disk: the holding disk |
| * |
| * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
| * |
| * This functions creates the following sysfs symlinks. |
| * |
| * - from "slaves" directory of the holder @disk to the claimed @bdev |
| * - from "holders" directory of the @bdev to the holder @disk |
| * |
| * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is |
| * passed to bd_link_disk_holder(), then: |
| * |
| * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
| * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 |
| * |
| * The caller must have claimed @bdev before calling this function and |
| * ensure that both @bdev and @disk are valid during the creation and |
| * lifetime of these symlinks. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) |
| { |
| struct bd_holder_disk *holder; |
| int ret = 0; |
| |
| mutex_lock(&bdev->bd_mutex); |
| |
| WARN_ON_ONCE(!bdev->bd_holder); |
| |
| /* FIXME: remove the following once add_disk() handles errors */ |
| if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) |
| goto out_unlock; |
| |
| holder = bd_find_holder_disk(bdev, disk); |
| if (holder) { |
| holder->refcnt++; |
| goto out_unlock; |
| } |
| |
| holder = kzalloc(sizeof(*holder), GFP_KERNEL); |
| if (!holder) { |
| ret = -ENOMEM; |
| goto out_unlock; |
| } |
| |
| INIT_LIST_HEAD(&holder->list); |
| holder->disk = disk; |
| holder->refcnt = 1; |
| |
| ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| if (ret) |
| goto out_free; |
| |
| ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); |
| if (ret) |
| goto out_del; |
| /* |
| * bdev could be deleted beneath us which would implicitly destroy |
| * the holder directory. Hold on to it. |
| */ |
| kobject_get(bdev->bd_part->holder_dir); |
| |
| list_add(&holder->list, &bdev->bd_holder_disks); |
| goto out_unlock; |
| |
| out_del: |
| del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| out_free: |
| kfree(holder); |
| out_unlock: |
| mutex_unlock(&bdev->bd_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(bd_link_disk_holder); |
| |
| /** |
| * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() |
| * @bdev: the calimed slave bdev |
| * @disk: the holding disk |
| * |
| * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
| * |
| * CONTEXT: |
| * Might sleep. |
| */ |
| void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) |
| { |
| struct bd_holder_disk *holder; |
| |
| mutex_lock(&bdev->bd_mutex); |
| |
| holder = bd_find_holder_disk(bdev, disk); |
| |
| if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { |
| del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| del_symlink(bdev->bd_part->holder_dir, |
| &disk_to_dev(disk)->kobj); |
| kobject_put(bdev->bd_part->holder_dir); |
| list_del_init(&holder->list); |
| kfree(holder); |
| } |
| |
| mutex_unlock(&bdev->bd_mutex); |
| } |
| EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
| #endif |
| |
| /** |
| * flush_disk - invalidates all buffer-cache entries on a disk |
| * |
| * @bdev: struct block device to be flushed |
| * @kill_dirty: flag to guide handling of dirty inodes |
| * |
| * Invalidates all buffer-cache entries on a disk. It should be called |
| * when a disk has been changed -- either by a media change or online |
| * resize. |
| */ |
| static void flush_disk(struct block_device *bdev, bool kill_dirty) |
| { |
| if (__invalidate_device(bdev, kill_dirty)) { |
| char name[BDEVNAME_SIZE] = ""; |
| |
| if (bdev->bd_disk) |
| disk_name(bdev->bd_disk, 0, name); |
| printk(KERN_WARNING "VFS: busy inodes on changed media or " |
| "resized disk %s\n", name); |
| } |
| |
| if (!bdev->bd_disk) |
| return; |
| if (disk_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, false); |
| } |
| } |
| EXPORT_SYMBOL(check_disk_size_change); |
| |
| /** |
| * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
| * @disk: struct gendisk to be revalidated |
| * |
| * This routine is a wrapper for lower-level driver's revalidate_disk |
| * call-backs. It is used to do common pre and post operations needed |
| * for all revalidate_disk operations. |
| */ |
| int revalidate_disk(struct gendisk *disk) |
| { |
| struct block_device *bdev; |
| int ret = 0; |
| |
| if (disk->fops->revalidate_disk) |
| ret = disk->fops->revalidate_disk(disk); |
| |
| bdev = bdget_disk(disk, 0); |
| if (!bdev) |
| return ret; |
| |
| mutex_lock(&bdev->bd_mutex); |
| check_disk_size_change(disk, bdev); |
| mutex_unlock(&bdev->bd_mutex); |
| bdput(bdev); |
| return ret; |
| } |
| EXPORT_SYMBOL(revalidate_disk); |
| |
| /* |
| * This routine checks whether a removable media has been changed, |
| * and invalidates all buffer-cache-entries in that case. This |
| * is a relatively slow routine, so we have to try to minimize using |
| * it. Thus it is called only upon a 'mount' or 'open'. This |
| * is the best way of combining speed and utility, I think. |
| * People changing diskettes in the middle of an operation deserve |
| * to lose :-) |
| */ |
| int check_disk_change(struct block_device *bdev) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| const struct block_device_operations *bdops = disk->fops; |
| unsigned int events; |
| |
| events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | |
| DISK_EVENT_EJECT_REQUEST); |
| if (!(events & DISK_EVENT_MEDIA_CHANGE)) |
| return 0; |
| |
| flush_disk(bdev, true); |
| if (bdops->revalidate_disk) |
| bdops->revalidate_disk(bdev->bd_disk); |
| return 1; |
| } |
| |
| EXPORT_SYMBOL(check_disk_change); |
| |
| void bd_set_size(struct block_device *bdev, loff_t size) |
| { |
| unsigned bsize = bdev_logical_block_size(bdev); |
| |
| bdev->bd_inode->i_size = size; |
| while (bsize < PAGE_CACHE_SIZE) { |
| if (size & bsize) |
| break; |
| bsize <<= 1; |
| } |
| bdev->bd_block_size = bsize; |
| bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
| } |
| EXPORT_SYMBOL(bd_set_size); |
| |
| static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
| |
| /* |
| * bd_mutex locking: |
| * |
| * mutex_lock(part->bd_mutex) |
| * mutex_lock_nested(whole->bd_mutex, 1) |
| */ |
| |
| static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
| { |
| struct gendisk *disk; |
| int ret; |
| int partno; |
| int perm = 0; |
| |
| if (mode & FMODE_READ) |
| perm |= MAY_READ; |
| if (mode & FMODE_WRITE) |
| perm |= MAY_WRITE; |
| /* |
| * hooks: /n/, see "layering violations". |
| */ |
| if (!for_part) { |
| ret = devcgroup_inode_permission(bdev->bd_inode, perm); |
| if (ret != 0) { |
| bdput(bdev); |
| return ret; |
| } |
| } |
| |
| restart: |
| |
| ret = -ENXIO; |
| disk = get_gendisk(bdev->bd_dev, &partno); |
| if (!disk) |
| goto out; |
| |
| disk_block_events(disk); |
| 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; |
| |
| ret = 0; |
| if (disk->fops->open) { |
| ret = disk->fops->open(bdev, mode); |
| if (ret == -ERESTARTSYS) { |
| /* Lost a race with 'disk' being |
| * deleted, try again. |
| * See md.c |
| */ |
| disk_put_part(bdev->bd_part); |
| bdev->bd_part = NULL; |
| bdev->bd_disk = NULL; |
| mutex_unlock(&bdev->bd_mutex); |
| disk_unblock_events(disk); |
| module_put(disk->fops->owner); |
| put_disk(disk); |
| goto restart; |
| } |
| } |
| |
| if (!ret && !bdev->bd_openers) { |
| bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
| bdi = blk_get_backing_dev_info(bdev); |
| if (bdi == NULL) |
| bdi = &default_backing_dev_info; |
| bdev_inode_switch_bdi(bdev->bd_inode, bdi); |
| } |
| |
| /* |
| * If the device is invalidated, rescan partition |
| * if open succeeded or failed with -ENOMEDIUM. |
| * The latter is necessary to prevent ghost |
| * partitions on a removed medium. |
| */ |
| if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM)) |
| rescan_partitions(disk, bdev); |
| if (ret) |
| goto out_clear; |
| } else { |
| struct block_device *whole; |
| whole = bdget_disk(disk, 0); |
| ret = -ENOMEM; |
| if (!whole) |
| goto out_clear; |
| BUG_ON(for_part); |
| ret = __blkdev_get(whole, mode, 1); |
| if (ret) |
| goto out_clear; |
| bdev->bd_contains = whole; |
| bdev_inode_switch_bdi(bdev->bd_inode, |
| whole->bd_inode->i_data.backing_dev_info); |
| bdev->bd_part = disk_get_part(disk, partno); |
| if (!(disk->flags & GENHD_FL_UP) || |
| !bdev->bd_part || !bdev->bd_part->nr_sects) { |
| ret = -ENXIO; |
| goto out_clear; |
| } |
| bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
| } |
| } else { |
| if (bdev->bd_contains == bdev) { |
| ret = 0; |
| if (bdev->bd_disk->fops->open) |
| ret = bdev->bd_disk->fops->open(bdev, mode); |
| /* the same as first opener case, read comment there */ |
| if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM)) |
| rescan_partitions(bdev->bd_disk, bdev); |
| if (ret) |
| goto out_unlock_bdev; |
| } |
| /* only one opener holds refs to the module and disk */ |
| module_put(disk->fops->owner); |
| put_disk(disk); |
| } |
| bdev->bd_openers++; |
| if (for_part) |
| bdev->bd_part_count++; |
| mutex_unlock(&bdev->bd_mutex); |
| disk_unblock_events(disk); |
| return 0; |
| |
| out_clear: |
| disk_put_part(bdev->bd_part); |
| bdev->bd_disk = NULL; |
| bdev->bd_part = NULL; |
| bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info); |
| if (bdev != bdev->bd_contains) |
| __blkdev_put(bdev->bd_contains, mode, 1); |
| bdev->bd_contains = NULL; |
| out_unlock_bdev: |
| mutex_unlock(&bdev->bd_mutex); |
| disk_unblock_events(disk); |
| module_put(disk->fops->owner); |
| put_disk(disk); |
| out: |
| bdput(bdev); |
| |
| return ret; |
| } |
| |
| /** |
| * blkdev_get - open a block device |
| * @bdev: block_device to open |
| * @mode: FMODE_* mask |
| * @holder: exclusive holder identifier |
| * |
| * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is |
| * open with exclusive access. Specifying %FMODE_EXCL with %NULL |
| * @holder is invalid. Exclusive opens may nest for the same @holder. |
| * |
| * On success, the reference count of @bdev is unchanged. On failure, |
| * @bdev is put. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) |
| { |
| struct block_device *whole = NULL; |
| int res; |
| |
| WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); |
| |
| if ((mode & FMODE_EXCL) && holder) { |
| whole = bd_start_claiming(bdev, holder); |
| if (IS_ERR(whole)) { |
| bdput(bdev); |
| return PTR_ERR(whole); |
| } |
| } |
| |
| res = __blkdev_get(bdev, mode, 0); |
| |
| if (whole) { |
| struct gendisk *disk = whole->bd_disk; |
| |
| /* finish claiming */ |
| mutex_lock(&bdev->bd_mutex); |
| spin_lock(&bdev_lock); |
| |
| if (!res) { |
| BUG_ON(!bd_may_claim(bdev, whole, holder)); |
| /* |
| * Note that for a whole device bd_holders |
| * will be incremented twice, and bd_holder |
| * will be set to bd_may_claim before being |
| * set to holder |
| */ |
| whole->bd_holders++; |
| whole->bd_holder = bd_may_claim; |
| bdev->bd_holders++; |
| bdev->bd_holder = holder; |
| } |
| |
| /* tell others that we're done */ |
| BUG_ON(whole->bd_claiming != holder); |
| whole->bd_claiming = NULL; |
| wake_up_bit(&whole->bd_claiming, 0); |
| |
| spin_unlock(&bdev_lock); |
| |
| /* |
| * Block event polling for write claims if requested. Any |
| * write holder makes the write_holder state stick until |
| * all are released. This is good enough and tracking |
| * individual writeable reference is too fragile given the |
| * way @mode is used in blkdev_get/put(). |
| */ |
| if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && |
| (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { |
| bdev->bd_write_holder = true; |
| disk_block_events(disk); |
| } |
| |
| mutex_unlock(&bdev->bd_mutex); |
| bdput(whole); |
| } |
| |
| return res; |
| } |
| EXPORT_SYMBOL(blkdev_get); |
| |
| /** |
| * blkdev_get_by_path - open a block device by name |
| * @path: path to the block device to open |
| * @mode: FMODE_* mask |
| * @holder: exclusive holder identifier |
| * |
| * Open the blockdevice described by the device file at @path. @mode |
| * and @holder are identical to blkdev_get(). |
| * |
| * On success, the returned block_device has reference count of one. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * Pointer to block_device on success, ERR_PTR(-errno) on failure. |
| */ |
| struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, |
| void *holder) |
| { |
| struct block_device *bdev; |
| int err; |
| |
| bdev = lookup_bdev(path); |
| if (IS_ERR(bdev)) |
| return bdev; |
| |
| err = blkdev_get(bdev, mode, holder); |
| if (err) |
| return ERR_PTR(err); |
| |
| if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
| blkdev_put(bdev, mode); |
| return ERR_PTR(-EACCES); |
| } |
| |
| return bdev; |
| } |
| EXPORT_SYMBOL(blkdev_get_by_path); |
| |
| /** |
| * blkdev_get_by_dev - open a block device by device number |
| * @dev: device number of block device to open |
| * @mode: FMODE_* mask |
| * @holder: exclusive holder identifier |
| * |
| * Open the blockdevice described by device number @dev. @mode and |
| * @holder are identical to blkdev_get(). |
| * |
| * Use it ONLY if you really do not have anything better - i.e. when |
| * you are behind a truly sucky interface and all you are given is a |
| * device number. _Never_ to be used for internal purposes. If you |
| * ever need it - reconsider your API. |
| * |
| * On success, the returned block_device has reference count of one. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * Pointer to block_device on success, ERR_PTR(-errno) on failure. |
| */ |
| struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) |
| { |
| struct block_device *bdev; |
| int err; |
| |
| bdev = bdget(dev); |
| if (!bdev) |
| return ERR_PTR(-ENOMEM); |
| |
| err = blkdev_get(bdev, mode, holder); |
| if (err) |
| return ERR_PTR(err); |
| |
| return bdev; |
| } |
| EXPORT_SYMBOL(blkdev_get_by_dev); |
| |
| static int blkdev_open(struct inode * inode, struct file * filp) |
| { |
| struct block_device *bdev; |
| |
| /* |
| * Preserve backwards compatibility and allow large file access |
| * even if userspace doesn't ask for it explicitly. Some mkfs |
| * binary needs it. We might want to drop this workaround |
| * during an unstable branch. |
| */ |
| filp->f_flags |= O_LARGEFILE; |
| |
| if (filp->f_flags & O_NDELAY) |
| filp->f_mode |= FMODE_NDELAY; |
| if (filp->f_flags & O_EXCL) |
| filp->f_mode |= FMODE_EXCL; |
| if ((filp->f_flags & O_ACCMODE) == 3) |
| filp->f_mode |= FMODE_WRITE_IOCTL; |
| |
| bdev = bd_acquire(inode); |
| if (bdev == NULL) |
| return -ENOMEM; |
| |
| filp->f_mapping = bdev->bd_inode->i_mapping; |
| |
| return blkdev_get(bdev, filp->f_mode, filp); |
| } |
| |
| static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
| { |
| int ret = 0; |
| struct gendisk *disk = bdev->bd_disk; |
| struct block_device *victim = NULL; |
| |
| mutex_lock_nested(&bdev->bd_mutex, for_part); |
| if (for_part) |
| bdev->bd_part_count--; |
| |
| if (!--bdev->bd_openers) { |
| WARN_ON_ONCE(bdev->bd_holders); |
| sync_blockdev(bdev); |
| kill_bdev(bdev); |
| } |
| 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_inode_switch_bdi(bdev->bd_inode, |
| &default_backing_dev_info); |
| if (bdev != bdev->bd_contains) |
| victim = bdev->bd_contains; |
| bdev->bd_contains = NULL; |
| } |
| 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) |
| { |
| if (mode & FMODE_EXCL) { |
| bool bdev_free; |
| |
| /* |
| * Release a claim on the device. The holder fields |
| * are protected with bdev_lock. bd_mutex is to |
| * synchronize disk_holder unlinking. |
| */ |
| mutex_lock(&bdev->bd_mutex); |
| spin_lock(&bdev_lock); |
| |
| WARN_ON_ONCE(--bdev->bd_holders < 0); |
| WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); |
| |
| /* bd_contains might point to self, check in a separate step */ |
| if ((bdev_free = !bdev->bd_holders)) |
| bdev->bd_holder = NULL; |
| if (!bdev->bd_contains->bd_holders) |
| bdev->bd_contains->bd_holder = NULL; |
| |
| spin_unlock(&bdev_lock); |
| |
| /* |
| * If this was the last claim, remove holder link and |
| * unblock evpoll if it was a write holder. |
| */ |
| if (bdev_free) { |
| if (bdev->bd_write_holder) { |
| disk_unblock_events(bdev->bd_disk); |
| disk_check_events(bdev->bd_disk); |
| bdev->bd_write_holder = false; |
| } |
| } |
| |
| mutex_unlock(&bdev->bd_mutex); |
| } |
| |
| return __blkdev_put(bdev, mode, 0); |
| } |
| EXPORT_SYMBOL(blkdev_put); |
| |
| static int blkdev_close(struct inode * inode, struct file * filp) |
| { |
| struct block_device *bdev = I_BDEV(filp->f_mapping->host); |
| |
| return blkdev_put(bdev, filp->f_mode); |
| } |
| |
| static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
| { |
| struct block_device *bdev = I_BDEV(file->f_mapping->host); |
| fmode_t mode = file->f_mode; |
| |
| /* |
| * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have |
| * to updated it before every ioctl. |
| */ |
| if (file->f_flags & O_NDELAY) |
| mode |= FMODE_NDELAY; |
| else |
| mode &= ~FMODE_NDELAY; |
| |
| return blkdev_ioctl(bdev, mode, cmd, arg); |
| } |
| |
| /* |
| * Write data to the block device. Only intended for the block device itself |
| * and the raw driver which basically is a fake block device. |
| * |
| * Does not take i_mutex for the write and thus is not for general purpose |
| * use. |
| */ |
| ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov, |
| unsigned long nr_segs, loff_t pos) |
| { |
| struct file *file = iocb->ki_filp; |
| ssize_t ret; |
| |
| BUG_ON(iocb->ki_pos != pos); |
| |
| ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); |
| if (ret > 0 || ret == -EIOCBQUEUED) { |
| ssize_t err; |
| |
| err = generic_write_sync(file, pos, ret); |
| if (err < 0 && ret > 0) |
| ret = err; |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(blkdev_aio_write); |
| |
| /* |
| * Try to release a page associated with block device when the system |
| * is under memory pressure. |
| */ |
| static int blkdev_releasepage(struct page *page, gfp_t wait) |
| { |
| struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; |
| |
| if (super && super->s_op->bdev_try_to_free_page) |
| return super->s_op->bdev_try_to_free_page(super, page, wait); |
| |
| return try_to_free_buffers(page); |
| } |
| |
| static const struct address_space_operations def_blk_aops = { |
| .readpage = blkdev_readpage, |
| .writepage = blkdev_writepage, |
| .write_begin = blkdev_write_begin, |
| .write_end = blkdev_write_end, |
| .writepages = generic_writepages, |
| .releasepage = blkdev_releasepage, |
| .direct_IO = blkdev_direct_IO, |
| }; |
| |
| const struct file_operations def_blk_fops = { |
| .open = blkdev_open, |
| .release = blkdev_close, |
| .llseek = block_llseek, |
| .read = do_sync_read, |
| .write = do_sync_write, |
| .aio_read = generic_file_aio_read, |
| .aio_write = blkdev_aio_write, |
| .mmap = generic_file_mmap, |
| .fsync = blkdev_fsync, |
| .unlocked_ioctl = block_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = compat_blkdev_ioctl, |
| #endif |
| .splice_read = generic_file_splice_read, |
| .splice_write = generic_file_splice_write, |
| }; |
| |
| int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) |
| { |
| int res; |
| mm_segment_t old_fs = get_fs(); |
| set_fs(KERNEL_DS); |
| res = blkdev_ioctl(bdev, 0, cmd, arg); |
| set_fs(old_fs); |
| return res; |
| } |
| |
| EXPORT_SYMBOL(ioctl_by_bdev); |
| |
| /** |
| * lookup_bdev - lookup a struct block_device by name |
| * @pathname: special file representing the block device |
| * |
| * Get a reference to the blockdevice at @pathname in the current |
| * namespace if possible and return it. Return ERR_PTR(error) |
| * otherwise. |
| */ |
| struct block_device *lookup_bdev(const char *pathname) |
| { |
| struct block_device *bdev; |
| struct inode *inode; |
| struct path path; |
| int error; |
| |
| if (!pathname || !*pathname) |
| return ERR_PTR(-EINVAL); |
| |
| error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
| if (error) |
| return ERR_PTR(error); |
| |
| inode = path.dentry->d_inode; |
| error = -ENOTBLK; |
| if (!S_ISBLK(inode->i_mode)) |
| goto fail; |
| error = -EACCES; |
| if (path.mnt->mnt_flags & MNT_NODEV) |
| goto fail; |
| error = -ENOMEM; |
| bdev = bd_acquire(inode); |
| if (!bdev) |
| goto fail; |
| out: |
| path_put(&path); |
| return bdev; |
| fail: |
| bdev = ERR_PTR(error); |
| goto out; |
| } |
| EXPORT_SYMBOL(lookup_bdev); |
| |
| int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
| { |
| struct super_block *sb = get_super(bdev); |
| int res = 0; |
| |
| if (sb) { |
| /* |
| * no need to lock the super, get_super holds the |
| * read mutex so the filesystem cannot go away |
| * under us (->put_super runs with the write lock |
| * hold). |
| */ |
| shrink_dcache_sb(sb); |
| res = invalidate_inodes(sb, kill_dirty); |
| drop_super(sb); |
| } |
| invalidate_bdev(bdev); |
| return res; |
| } |
| EXPORT_SYMBOL(__invalidate_device); |