| /* |
| * 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/smp_lock.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/writeback.h> |
| #include <linux/mpage.h> |
| #include <linux/mount.h> |
| #include <linux/uio.h> |
| #include <linux/namei.h> |
| #include <linux/log2.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); |
| |
| 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_hardsect_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_hardsect_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_no_locking(rw, iocb, inode, I_BDEV(inode), |
| iov, offset, nr_segs, blkdev_get_blocks, NULL); |
| } |
| |
| 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) |
| { |
| *pagep = NULL; |
| return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, |
| 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; |
| } |
| |
| /* |
| * Filp is never NULL; the only case when ->fsync() is called with |
| * NULL first argument is nfsd_sync_dir() and that's not a directory. |
| */ |
| |
| static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) |
| { |
| return sync_blockdev(I_BDEV(filp->f_mapping->host)); |
| } |
| |
| /* |
| * 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_destroy_inode(struct inode *inode) |
| { |
| struct bdev_inode *bdi = BDEV_I(inode); |
| |
| bdi->bdev.bd_inode_backing_dev_info = NULL; |
| kmem_cache_free(bdev_cachep, bdi); |
| } |
| |
| 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); |
| sema_init(&bdev->bd_mount_sem, 1); |
| INIT_LIST_HEAD(&bdev->bd_inodes); |
| INIT_LIST_HEAD(&bdev->bd_list); |
| #ifdef CONFIG_SYSFS |
| INIT_LIST_HEAD(&bdev->bd_holder_list); |
| #endif |
| inode_init_once(&ei->vfs_inode); |
| } |
| |
| 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_clear_inode(struct inode *inode) |
| { |
| struct block_device *bdev = &BDEV_I(inode)->bdev; |
| struct list_head *p; |
| 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, |
| .clear_inode = bdev_clear_inode, |
| }; |
| |
| static int bd_get_sb(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data, struct vfsmount *mnt) |
| { |
| return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt); |
| } |
| |
| static struct file_system_type bd_type = { |
| .name = "bdev", |
| .get_sb = bd_get_sb, |
| .kill_sb = kill_anon_super, |
| }; |
| |
| static struct vfsmount *bd_mnt __read_mostly; |
| struct super_block *blockdev_superblock; |
| |
| void __init bdev_cache_init(void) |
| { |
| int err; |
| bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
| 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
| SLAB_MEM_SPREAD|SLAB_PANIC), |
| init_once); |
| err = register_filesystem(&bd_type); |
| if (err) |
| panic("Cannot register bdev pseudo-fs"); |
| bd_mnt = kern_mount(&bd_type); |
| if (IS_ERR(bd_mnt)) |
| panic("Cannot create bdev pseudo-fs"); |
| blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
| } |
| |
| /* |
| * Most likely _very_ bad one - but then it's hardly critical for small |
| * /dev and can be fixed when somebody will need really large one. |
| * Keep in mind that it will be fed through icache hash function too. |
| */ |
| static inline unsigned long hash(dev_t dev) |
| { |
| return MAJOR(dev)+MINOR(dev); |
| } |
| |
| static int bdev_test(struct inode *inode, void *data) |
| { |
| return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; |
| } |
| |
| static int bdev_set(struct inode *inode, void *data) |
| { |
| BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; |
| return 0; |
| } |
| |
| static LIST_HEAD(all_bdevs); |
| |
| struct block_device *bdget(dev_t dev) |
| { |
| struct block_device *bdev; |
| struct inode *inode; |
| |
| inode = iget5_locked(bd_mnt->mnt_sb, 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); |
| |
| long nr_blockdev_pages(void) |
| { |
| struct block_device *bdev; |
| long ret = 0; |
| spin_lock(&bdev_lock); |
| list_for_each_entry(bdev, &all_bdevs, bd_list) { |
| ret += bdev->bd_inode->i_mapping->nrpages; |
| } |
| spin_unlock(&bdev_lock); |
| return ret; |
| } |
| |
| void bdput(struct block_device *bdev) |
| { |
| iput(bdev->bd_inode); |
| } |
| |
| EXPORT_SYMBOL(bdput); |
| |
| static struct block_device *bd_acquire(struct inode *inode) |
| { |
| struct block_device *bdev; |
| |
| spin_lock(&bdev_lock); |
| bdev = inode->i_bdev; |
| if (bdev) { |
| atomic_inc(&bdev->bd_inode->i_count); |
| spin_unlock(&bdev_lock); |
| return bdev; |
| } |
| spin_unlock(&bdev_lock); |
| |
| bdev = bdget(inode->i_rdev); |
| if (bdev) { |
| spin_lock(&bdev_lock); |
| if (!inode->i_bdev) { |
| /* |
| * We take an additional bd_inode->i_count for inode, |
| * and it's released in clear_inode() of inode. |
| * So, we can access it via ->i_mapping always |
| * without igrab(). |
| */ |
| atomic_inc(&bdev->bd_inode->i_count); |
| inode->i_bdev = bdev; |
| inode->i_mapping = bdev->bd_inode->i_mapping; |
| list_add(&inode->i_devices, &bdev->bd_inodes); |
| } |
| spin_unlock(&bdev_lock); |
| } |
| return bdev; |
| } |
| |
| /* Call when you free inode */ |
| |
| void bd_forget(struct inode *inode) |
| { |
| struct block_device *bdev = NULL; |
| |
| spin_lock(&bdev_lock); |
| if (inode->i_bdev) { |
| if (inode->i_sb != blockdev_superblock) |
| bdev = inode->i_bdev; |
| __bd_forget(inode); |
| } |
| spin_unlock(&bdev_lock); |
| |
| if (bdev) |
| iput(bdev->bd_inode); |
| } |
| |
| int bd_claim(struct block_device *bdev, void *holder) |
| { |
| int res; |
| spin_lock(&bdev_lock); |
| |
| /* first decide result */ |
| if (bdev->bd_holder == holder) |
| res = 0; /* already a holder */ |
| else if (bdev->bd_holder != NULL) |
| res = -EBUSY; /* held by someone else */ |
| else if (bdev->bd_contains == bdev) |
| res = 0; /* is a whole device which isn't held */ |
| |
| else if (bdev->bd_contains->bd_holder == bd_claim) |
| res = 0; /* is a partition of a device that is being partitioned */ |
| else if (bdev->bd_contains->bd_holder != NULL) |
| res = -EBUSY; /* is a partition of a held device */ |
| else |
| res = 0; /* is a partition of an un-held device */ |
| |
| /* now impose change */ |
| if (res==0) { |
| /* note that for a whole device bd_holders |
| * will be incremented twice, and bd_holder will |
| * be set to bd_claim before being set to holder |
| */ |
| bdev->bd_contains->bd_holders ++; |
| bdev->bd_contains->bd_holder = bd_claim; |
| bdev->bd_holders++; |
| bdev->bd_holder = holder; |
| } |
| spin_unlock(&bdev_lock); |
| return res; |
| } |
| |
| EXPORT_SYMBOL(bd_claim); |
| |
| void bd_release(struct block_device *bdev) |
| { |
| spin_lock(&bdev_lock); |
| if (!--bdev->bd_contains->bd_holders) |
| bdev->bd_contains->bd_holder = NULL; |
| if (!--bdev->bd_holders) |
| bdev->bd_holder = NULL; |
| spin_unlock(&bdev_lock); |
| } |
| |
| EXPORT_SYMBOL(bd_release); |
| |
| #ifdef CONFIG_SYSFS |
| /* |
| * Functions for bd_claim_by_kobject / bd_release_from_kobject |
| * |
| * If a kobject is passed to bd_claim_by_kobject() |
| * and the kobject has a parent directory, |
| * following symlinks are created: |
| * o from the kobject to the claimed bdev |
| * o from "holders" directory of the bdev to the parent of the kobject |
| * bd_release_from_kobject() removes these symlinks. |
| * |
| * Example: |
| * If /dev/dm-0 maps to /dev/sda, kobject corresponding to |
| * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: |
| * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
| * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 |
| */ |
| |
| static int add_symlink(struct kobject *from, struct kobject *to) |
| { |
| if (!from || !to) |
| return 0; |
| return sysfs_create_link(from, to, kobject_name(to)); |
| } |
| |
| static void del_symlink(struct kobject *from, struct kobject *to) |
| { |
| if (!from || !to) |
| return; |
| sysfs_remove_link(from, kobject_name(to)); |
| } |
| |
| /* |
| * 'struct bd_holder' contains pointers to kobjects symlinked by |
| * bd_claim_by_kobject. |
| * It's connected to bd_holder_list which is protected by bdev->bd_sem. |
| */ |
| struct bd_holder { |
| struct list_head list; /* chain of holders of the bdev */ |
| int count; /* references from the holder */ |
| struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ |
| struct kobject *hdev; /* e.g. "/block/dm-0" */ |
| struct kobject *hdir; /* e.g. "/block/sda/holders" */ |
| struct kobject *sdev; /* e.g. "/block/sda" */ |
| }; |
| |
| /* |
| * Get references of related kobjects at once. |
| * Returns 1 on success. 0 on failure. |
| * |
| * Should call bd_holder_release_dirs() after successful use. |
| */ |
| static int bd_holder_grab_dirs(struct block_device *bdev, |
| struct bd_holder *bo) |
| { |
| if (!bdev || !bo) |
| return 0; |
| |
| bo->sdir = kobject_get(bo->sdir); |
| if (!bo->sdir) |
| return 0; |
| |
| bo->hdev = kobject_get(bo->sdir->parent); |
| if (!bo->hdev) |
| goto fail_put_sdir; |
| |
| bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); |
| if (!bo->sdev) |
| goto fail_put_hdev; |
| |
| bo->hdir = kobject_get(bdev->bd_part->holder_dir); |
| if (!bo->hdir) |
| goto fail_put_sdev; |
| |
| return 1; |
| |
| fail_put_sdev: |
| kobject_put(bo->sdev); |
| fail_put_hdev: |
| kobject_put(bo->hdev); |
| fail_put_sdir: |
| kobject_put(bo->sdir); |
| |
| return 0; |
| } |
| |
| /* Put references of related kobjects at once. */ |
| static void bd_holder_release_dirs(struct bd_holder *bo) |
| { |
| kobject_put(bo->hdir); |
| kobject_put(bo->sdev); |
| kobject_put(bo->hdev); |
| kobject_put(bo->sdir); |
| } |
| |
| static struct bd_holder *alloc_bd_holder(struct kobject *kobj) |
| { |
| struct bd_holder *bo; |
| |
| bo = kzalloc(sizeof(*bo), GFP_KERNEL); |
| if (!bo) |
| return NULL; |
| |
| bo->count = 1; |
| bo->sdir = kobj; |
| |
| return bo; |
| } |
| |
| static void free_bd_holder(struct bd_holder *bo) |
| { |
| kfree(bo); |
| } |
| |
| /** |
| * find_bd_holder - find matching struct bd_holder from the block device |
| * |
| * @bdev: struct block device to be searched |
| * @bo: target struct bd_holder |
| * |
| * Returns matching entry with @bo in @bdev->bd_holder_list. |
| * If found, increment the reference count and return the pointer. |
| * If not found, returns NULL. |
| */ |
| static struct bd_holder *find_bd_holder(struct block_device *bdev, |
| struct bd_holder *bo) |
| { |
| struct bd_holder *tmp; |
| |
| list_for_each_entry(tmp, &bdev->bd_holder_list, list) |
| if (tmp->sdir == bo->sdir) { |
| tmp->count++; |
| return tmp; |
| } |
| |
| return NULL; |
| } |
| |
| /** |
| * add_bd_holder - create sysfs symlinks for bd_claim() relationship |
| * |
| * @bdev: block device to be bd_claimed |
| * @bo: preallocated and initialized by alloc_bd_holder() |
| * |
| * Add @bo to @bdev->bd_holder_list, create symlinks. |
| * |
| * Returns 0 if symlinks are created. |
| * Returns -ve if something fails. |
| */ |
| static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) |
| { |
| int err; |
| |
| if (!bo) |
| return -EINVAL; |
| |
| if (!bd_holder_grab_dirs(bdev, bo)) |
| return -EBUSY; |
| |
| err = add_symlink(bo->sdir, bo->sdev); |
| if (err) |
| return err; |
| |
| err = add_symlink(bo->hdir, bo->hdev); |
| if (err) { |
| del_symlink(bo->sdir, bo->sdev); |
| return err; |
| } |
| |
| list_add_tail(&bo->list, &bdev->bd_holder_list); |
| return 0; |
| } |
| |
| /** |
| * del_bd_holder - delete sysfs symlinks for bd_claim() relationship |
| * |
| * @bdev: block device to be bd_claimed |
| * @kobj: holder's kobject |
| * |
| * If there is matching entry with @kobj in @bdev->bd_holder_list |
| * and no other bd_claim() from the same kobject, |
| * remove the struct bd_holder from the list, delete symlinks for it. |
| * |
| * Returns a pointer to the struct bd_holder when it's removed from the list |
| * and ready to be freed. |
| * Returns NULL if matching claim isn't found or there is other bd_claim() |
| * by the same kobject. |
| */ |
| static struct bd_holder *del_bd_holder(struct block_device *bdev, |
| struct kobject *kobj) |
| { |
| struct bd_holder *bo; |
| |
| list_for_each_entry(bo, &bdev->bd_holder_list, list) { |
| if (bo->sdir == kobj) { |
| bo->count--; |
| BUG_ON(bo->count < 0); |
| if (!bo->count) { |
| list_del(&bo->list); |
| del_symlink(bo->sdir, bo->sdev); |
| del_symlink(bo->hdir, bo->hdev); |
| bd_holder_release_dirs(bo); |
| return bo; |
| } |
| break; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /** |
| * bd_claim_by_kobject - bd_claim() with additional kobject signature |
| * |
| * @bdev: block device to be claimed |
| * @holder: holder's signature |
| * @kobj: holder's kobject |
| * |
| * Do bd_claim() and if it succeeds, create sysfs symlinks between |
| * the bdev and the holder's kobject. |
| * Use bd_release_from_kobject() when relesing the claimed bdev. |
| * |
| * Returns 0 on success. (same as bd_claim()) |
| * Returns errno on failure. |
| */ |
| static int bd_claim_by_kobject(struct block_device *bdev, void *holder, |
| struct kobject *kobj) |
| { |
| int err; |
| struct bd_holder *bo, *found; |
| |
| if (!kobj) |
| return -EINVAL; |
| |
| bo = alloc_bd_holder(kobj); |
| if (!bo) |
| return -ENOMEM; |
| |
| mutex_lock(&bdev->bd_mutex); |
| |
| err = bd_claim(bdev, holder); |
| if (err) |
| goto fail; |
| |
| found = find_bd_holder(bdev, bo); |
| if (found) |
| goto fail; |
| |
| err = add_bd_holder(bdev, bo); |
| if (err) |
| bd_release(bdev); |
| else |
| bo = NULL; |
| fail: |
| mutex_unlock(&bdev->bd_mutex); |
| free_bd_holder(bo); |
| return err; |
| } |
| |
| /** |
| * bd_release_from_kobject - bd_release() with additional kobject signature |
| * |
| * @bdev: block device to be released |
| * @kobj: holder's kobject |
| * |
| * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). |
| */ |
| static void bd_release_from_kobject(struct block_device *bdev, |
| struct kobject *kobj) |
| { |
| if (!kobj) |
| return; |
| |
| mutex_lock(&bdev->bd_mutex); |
| bd_release(bdev); |
| free_bd_holder(del_bd_holder(bdev, kobj)); |
| mutex_unlock(&bdev->bd_mutex); |
| } |
| |
| /** |
| * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() |
| * |
| * @bdev: block device to be claimed |
| * @holder: holder's signature |
| * @disk: holder's gendisk |
| * |
| * Call bd_claim_by_kobject() with getting @disk->slave_dir. |
| */ |
| int bd_claim_by_disk(struct block_device *bdev, void *holder, |
| struct gendisk *disk) |
| { |
| return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); |
| } |
| EXPORT_SYMBOL_GPL(bd_claim_by_disk); |
| |
| /** |
| * bd_release_from_disk - wrapper function for bd_release_from_kobject() |
| * |
| * @bdev: block device to be claimed |
| * @disk: holder's gendisk |
| * |
| * Call bd_release_from_kobject() and put @disk->slave_dir. |
| */ |
| void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) |
| { |
| bd_release_from_kobject(bdev, disk->slave_dir); |
| kobject_put(disk->slave_dir); |
| } |
| EXPORT_SYMBOL_GPL(bd_release_from_disk); |
| #endif |
| |
| /* |
| * Tries to open block device by device number. Use it ONLY if you |
| * really do not have anything better - i.e. when you are behind a |
| * truly sucky interface and all you are given is a device number. _Never_ |
| * to be used for internal purposes. If you ever need it - reconsider |
| * your API. |
| */ |
| struct block_device *open_by_devnum(dev_t dev, fmode_t mode) |
| { |
| struct block_device *bdev = bdget(dev); |
| int err = -ENOMEM; |
| int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY; |
| if (bdev) |
| err = blkdev_get(bdev, mode, flags); |
| return err ? ERR_PTR(err) : bdev; |
| } |
| |
| EXPORT_SYMBOL(open_by_devnum); |
| |
| /** |
| * flush_disk - invalidates all buffer-cache entries on a disk |
| * |
| * @bdev: struct block device to be flushed |
| * |
| * Invalidates all buffer-cache entries on a disk. It should be called |
| * when a disk has been changed -- either by a media change or online |
| * resize. |
| */ |
| static void flush_disk(struct block_device *bdev) |
| { |
| if (__invalidate_device(bdev)) { |
| char name[BDEVNAME_SIZE] = ""; |
| |
| if (bdev->bd_disk) |
| disk_name(bdev->bd_disk, 0, name); |
| printk(KERN_WARNING "VFS: busy inodes on changed media or " |
| "resized disk %s\n", name); |
| } |
| |
| if (!bdev->bd_disk) |
| return; |
| if (disk_partitionable(bdev->bd_disk)) |
| bdev->bd_invalidated = 1; |
| } |
| |
| /** |
| * check_disk_size_change - checks for disk size change and adjusts bdev size. |
| * @disk: struct gendisk to check |
| * @bdev: struct bdev to adjust. |
| * |
| * This routine checks to see if the bdev size does not match the disk size |
| * and adjusts it if it differs. |
| */ |
| void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) |
| { |
| loff_t disk_size, bdev_size; |
| |
| disk_size = (loff_t)get_capacity(disk) << 9; |
| bdev_size = i_size_read(bdev->bd_inode); |
| if (disk_size != bdev_size) { |
| char name[BDEVNAME_SIZE]; |
| |
| disk_name(disk, 0, name); |
| printk(KERN_INFO |
| "%s: detected capacity change from %lld to %lld\n", |
| name, bdev_size, disk_size); |
| i_size_write(bdev->bd_inode, disk_size); |
| flush_disk(bdev); |
| } |
| } |
| EXPORT_SYMBOL(check_disk_size_change); |
| |
| /** |
| * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
| * @disk: struct gendisk to be revalidated |
| * |
| * This routine is a wrapper for lower-level driver's revalidate_disk |
| * call-backs. It is used to do common pre and post operations needed |
| * for all revalidate_disk operations. |
| */ |
| int revalidate_disk(struct gendisk *disk) |
| { |
| struct block_device *bdev; |
| int ret = 0; |
| |
| if (disk->fops->revalidate_disk) |
| ret = disk->fops->revalidate_disk(disk); |
| |
| bdev = bdget_disk(disk, 0); |
| if (!bdev) |
| return ret; |
| |
| mutex_lock(&bdev->bd_mutex); |
| check_disk_size_change(disk, bdev); |
| mutex_unlock(&bdev->bd_mutex); |
| bdput(bdev); |
| return ret; |
| } |
| EXPORT_SYMBOL(revalidate_disk); |
| |
| /* |
| * This routine checks whether a removable media has been changed, |
| * and invalidates all buffer-cache-entries in that case. This |
| * is a relatively slow routine, so we have to try to minimize using |
| * it. Thus it is called only upon a 'mount' or 'open'. This |
| * is the best way of combining speed and utility, I think. |
| * People changing diskettes in the middle of an operation deserve |
| * to lose :-) |
| */ |
| int check_disk_change(struct block_device *bdev) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| struct block_device_operations * bdops = disk->fops; |
| |
| if (!bdops->media_changed) |
| return 0; |
| if (!bdops->media_changed(bdev->bd_disk)) |
| return 0; |
| |
| flush_disk(bdev); |
| if (bdops->revalidate_disk) |
| bdops->revalidate_disk(bdev->bd_disk); |
| return 1; |
| } |
| |
| EXPORT_SYMBOL(check_disk_change); |
| |
| void bd_set_size(struct block_device *bdev, loff_t size) |
| { |
| unsigned bsize = bdev_hardsect_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_get(struct block_device *bdev, fmode_t mode, unsigned flags, |
| int for_part); |
| 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 do_open(struct block_device *bdev, struct file *file, int for_part) |
| { |
| struct gendisk *disk; |
| struct hd_struct *part = NULL; |
| int ret; |
| int partno; |
| int perm = 0; |
| |
| if (file->f_mode & FMODE_READ) |
| perm |= MAY_READ; |
| if (file->f_mode & FMODE_WRITE) |
| perm |= MAY_WRITE; |
| /* |
| * hooks: /n/, see "layering violations". |
| */ |
| ret = devcgroup_inode_permission(bdev->bd_inode, perm); |
| if (ret != 0) { |
| bdput(bdev); |
| return ret; |
| } |
| |
| if (file->f_flags & O_NDELAY) |
| file->f_mode |= FMODE_NDELAY; |
| if (file->f_flags & O_EXCL) |
| file->f_mode |= FMODE_EXCL; |
| if ((file->f_flags & O_ACCMODE) == 3) |
| file->f_mode |= FMODE_WRITE_IOCTL; |
| |
| ret = -ENXIO; |
| file->f_mapping = bdev->bd_inode->i_mapping; |
| |
| lock_kernel(); |
| |
| disk = get_gendisk(bdev->bd_dev, &partno); |
| if (!disk) |
| goto out_unlock_kernel; |
| part = disk_get_part(disk, partno); |
| if (!part) |
| goto out_unlock_kernel; |
| |
| mutex_lock_nested(&bdev->bd_mutex, for_part); |
| if (!bdev->bd_openers) { |
| bdev->bd_disk = disk; |
| bdev->bd_part = part; |
| bdev->bd_contains = bdev; |
| if (!partno) { |
| struct backing_dev_info *bdi; |
| if (disk->fops->open) { |
| ret = disk->fops->open(bdev, file->f_mode); |
| if (ret) |
| goto out_clear; |
| } |
| if (!bdev->bd_openers) { |
| bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
| bdi = blk_get_backing_dev_info(bdev); |
| if (bdi == NULL) |
| bdi = &default_backing_dev_info; |
| bdev->bd_inode->i_data.backing_dev_info = bdi; |
| } |
| if (bdev->bd_invalidated) |
| rescan_partitions(disk, bdev); |
| } else { |
| struct block_device *whole; |
| whole = bdget_disk(disk, 0); |
| ret = -ENOMEM; |
| if (!whole) |
| goto out_clear; |
| BUG_ON(for_part); |
| ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1); |
| if (ret) |
| goto out_clear; |
| bdev->bd_contains = whole; |
| bdev->bd_inode->i_data.backing_dev_info = |
| whole->bd_inode->i_data.backing_dev_info; |
| if (!(disk->flags & GENHD_FL_UP) || |
| !part || !part->nr_sects) { |
| ret = -ENXIO; |
| goto out_clear; |
| } |
| bd_set_size(bdev, (loff_t)part->nr_sects << 9); |
| } |
| } else { |
| disk_put_part(part); |
| put_disk(disk); |
| module_put(disk->fops->owner); |
| part = NULL; |
| disk = NULL; |
| if (bdev->bd_contains == bdev) { |
| if (bdev->bd_disk->fops->open) { |
| ret = bdev->bd_disk->fops->open(bdev, file->f_mode); |
| if (ret) |
| goto out_unlock_bdev; |
| } |
| if (bdev->bd_invalidated) |
| rescan_partitions(bdev->bd_disk, bdev); |
| } |
| } |
| bdev->bd_openers++; |
| if (for_part) |
| bdev->bd_part_count++; |
| mutex_unlock(&bdev->bd_mutex); |
| unlock_kernel(); |
| return 0; |
| |
| out_clear: |
| bdev->bd_disk = NULL; |
| bdev->bd_part = NULL; |
| bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
| if (bdev != bdev->bd_contains) |
| __blkdev_put(bdev->bd_contains, file->f_mode, 1); |
| bdev->bd_contains = NULL; |
| out_unlock_bdev: |
| mutex_unlock(&bdev->bd_mutex); |
| out_unlock_kernel: |
| unlock_kernel(); |
| |
| disk_put_part(part); |
| if (disk) |
| module_put(disk->fops->owner); |
| put_disk(disk); |
| bdput(bdev); |
| |
| return ret; |
| } |
| |
| static int __blkdev_get(struct block_device *bdev, fmode_t mode, unsigned flags, |
| int for_part) |
| { |
| /* |
| * This crockload is due to bad choice of ->open() type. |
| * It will go away. |
| * For now, block device ->open() routine must _not_ |
| * examine anything in 'inode' argument except ->i_rdev. |
| */ |
| struct file fake_file = {}; |
| struct dentry fake_dentry = {}; |
| fake_file.f_mode = mode; |
| fake_file.f_flags = flags; |
| fake_file.f_path.dentry = &fake_dentry; |
| fake_dentry.d_inode = bdev->bd_inode; |
| |
| return do_open(bdev, &fake_file, for_part); |
| } |
| |
| int blkdev_get(struct block_device *bdev, fmode_t mode, unsigned flags) |
| { |
| return __blkdev_get(bdev, mode, flags, 0); |
| } |
| EXPORT_SYMBOL(blkdev_get); |
| |
| static int blkdev_open(struct inode * inode, struct file * filp) |
| { |
| struct block_device *bdev; |
| int res; |
| |
| /* |
| * Preserve backwards compatibility and allow large file access |
| * even if userspace doesn't ask for it explicitly. Some mkfs |
| * binary needs it. We might want to drop this workaround |
| * during an unstable branch. |
| */ |
| filp->f_flags |= O_LARGEFILE; |
| |
| bdev = bd_acquire(inode); |
| if (bdev == NULL) |
| return -ENOMEM; |
| |
| res = do_open(bdev, filp, 0); |
| if (res) |
| return res; |
| |
| if (!(filp->f_flags & O_EXCL) ) |
| return 0; |
| |
| if (!(res = bd_claim(bdev, filp))) |
| return 0; |
| |
| blkdev_put(bdev, filp->f_mode); |
| return res; |
| } |
| |
| static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
| { |
| int ret = 0; |
| struct gendisk *disk = bdev->bd_disk; |
| struct block_device *victim = NULL; |
| |
| mutex_lock_nested(&bdev->bd_mutex, for_part); |
| lock_kernel(); |
| if (for_part) |
| bdev->bd_part_count--; |
| |
| if (!--bdev->bd_openers) { |
| sync_blockdev(bdev); |
| kill_bdev(bdev); |
| } |
| if (bdev->bd_contains == bdev) { |
| if (disk->fops->release) |
| ret = disk->fops->release(disk, mode); |
| } |
| if (!bdev->bd_openers) { |
| struct module *owner = disk->fops->owner; |
| |
| put_disk(disk); |
| module_put(owner); |
| disk_put_part(bdev->bd_part); |
| bdev->bd_part = NULL; |
| bdev->bd_disk = NULL; |
| bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
| if (bdev != bdev->bd_contains) |
| victim = bdev->bd_contains; |
| bdev->bd_contains = NULL; |
| } |
| unlock_kernel(); |
| mutex_unlock(&bdev->bd_mutex); |
| bdput(bdev); |
| if (victim) |
| __blkdev_put(victim, mode, 1); |
| return ret; |
| } |
| |
| int blkdev_put(struct block_device *bdev, fmode_t mode) |
| { |
| return __blkdev_put(bdev, mode, 0); |
| } |
| EXPORT_SYMBOL(blkdev_put); |
| |
| static int blkdev_close(struct inode * inode, struct file * filp) |
| { |
| struct block_device *bdev = I_BDEV(filp->f_mapping->host); |
| if (bdev->bd_holder == filp) |
| bd_release(bdev); |
| return blkdev_put(bdev, filp->f_mode); |
| } |
| |
| static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
| { |
| return blkdev_ioctl(file->f_mapping->host, file, cmd, arg); |
| } |
| |
| static const struct address_space_operations def_blk_aops = { |
| .readpage = blkdev_readpage, |
| .writepage = blkdev_writepage, |
| .sync_page = block_sync_page, |
| .write_begin = blkdev_write_begin, |
| .write_end = blkdev_write_end, |
| .writepages = generic_writepages, |
| .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 = generic_file_aio_write_nolock, |
| .mmap = generic_file_mmap, |
| .fsync = block_fsync, |
| .unlocked_ioctl = block_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = compat_blkdev_ioctl, |
| #endif |
| .splice_read = generic_file_splice_read, |
| .splice_write = generic_file_splice_write, |
| }; |
| |
| int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) |
| { |
| int res; |
| mm_segment_t old_fs = get_fs(); |
| set_fs(KERNEL_DS); |
| res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg); |
| set_fs(old_fs); |
| return res; |
| } |
| |
| EXPORT_SYMBOL(ioctl_by_bdev); |
| |
| /** |
| * lookup_bdev - lookup a struct block_device by name |
| * @path: 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 *path) |
| { |
| struct block_device *bdev; |
| struct inode *inode; |
| struct nameidata nd; |
| int error; |
| |
| if (!path || !*path) |
| return ERR_PTR(-EINVAL); |
| |
| error = path_lookup(path, LOOKUP_FOLLOW, &nd); |
| if (error) |
| return ERR_PTR(error); |
| |
| inode = nd.path.dentry->d_inode; |
| error = -ENOTBLK; |
| if (!S_ISBLK(inode->i_mode)) |
| goto fail; |
| error = -EACCES; |
| if (nd.path.mnt->mnt_flags & MNT_NODEV) |
| goto fail; |
| error = -ENOMEM; |
| bdev = bd_acquire(inode); |
| if (!bdev) |
| goto fail; |
| out: |
| path_put(&nd.path); |
| return bdev; |
| fail: |
| bdev = ERR_PTR(error); |
| goto out; |
| } |
| EXPORT_SYMBOL(lookup_bdev); |
| |
| /** |
| * open_bdev_excl - open a block device by name and set it up for use |
| * |
| * @path: special file representing the block device |
| * @flags: %MS_RDONLY for opening read-only |
| * @holder: owner for exclusion |
| * |
| * Open the blockdevice described by the special file at @path, claim it |
| * for the @holder. |
| */ |
| struct block_device *open_bdev_excl(const char *path, int flags, void *holder) |
| { |
| struct block_device *bdev; |
| fmode_t mode = FMODE_READ; |
| int error = 0; |
| |
| bdev = lookup_bdev(path); |
| if (IS_ERR(bdev)) |
| return bdev; |
| |
| if (!(flags & MS_RDONLY)) |
| mode |= FMODE_WRITE; |
| error = blkdev_get(bdev, mode, 0); |
| if (error) |
| return ERR_PTR(error); |
| error = -EACCES; |
| if (!(flags & MS_RDONLY) && bdev_read_only(bdev)) |
| goto blkdev_put; |
| error = bd_claim(bdev, holder); |
| if (error) |
| goto blkdev_put; |
| |
| return bdev; |
| |
| blkdev_put: |
| blkdev_put(bdev, mode); |
| return ERR_PTR(error); |
| } |
| |
| EXPORT_SYMBOL(open_bdev_excl); |
| |
| /** |
| * close_bdev_excl - release a blockdevice openen by open_bdev_excl() |
| * |
| * @bdev: blockdevice to close |
| * |
| * This is the counterpart to open_bdev_excl(). |
| */ |
| void close_bdev_excl(struct block_device *bdev) |
| { |
| bd_release(bdev); |
| blkdev_put(bdev, 0); /* move up in the next patches */ |
| } |
| |
| EXPORT_SYMBOL(close_bdev_excl); |
| |
| int __invalidate_device(struct block_device *bdev) |
| { |
| struct super_block *sb = get_super(bdev); |
| int res = 0; |
| |
| if (sb) { |
| /* |
| * no need to lock the super, get_super holds the |
| * read mutex so the filesystem cannot go away |
| * under us (->put_super runs with the write lock |
| * hold). |
| */ |
| shrink_dcache_sb(sb); |
| res = invalidate_inodes(sb); |
| drop_super(sb); |
| } |
| invalidate_bdev(bdev); |
| return res; |
| } |
| EXPORT_SYMBOL(__invalidate_device); |