/* * 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/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 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); } #if 0 static int blk_end_aio(struct bio *bio, unsigned int bytes_done, int error) { struct kiocb *iocb = bio->bi_private; atomic_t *bio_count = &iocb->ki_bio_count; if (bio_data_dir(bio) == READ) bio_check_pages_dirty(bio); else { bio_release_pages(bio); bio_put(bio); } /* iocb->ki_nbytes stores error code from LLDD */ if (error) iocb->ki_nbytes = -EIO; if (atomic_dec_and_test(bio_count)) { if ((long)iocb->ki_nbytes < 0) aio_complete(iocb, iocb->ki_nbytes, 0); else aio_complete(iocb, iocb->ki_left, 0); } return 0; } #define VEC_SIZE 16 struct pvec { unsigned short nr; unsigned short idx; struct page *page[VEC_SIZE]; }; #define PAGES_SPANNED(addr, len) \ (DIV_ROUND_UP((addr) + (len), PAGE_SIZE) - (addr) / PAGE_SIZE); /* * get page pointer for user addr, we internally cache struct page array for * (addr, count) range in pvec to avoid frequent call to get_user_pages. If * internal page list is exhausted, a batch count of up to VEC_SIZE is used * to get next set of page struct. */ static struct page *blk_get_page(unsigned long addr, size_t count, int rw, struct pvec *pvec) { int ret, nr_pages; if (pvec->idx == pvec->nr) { nr_pages = PAGES_SPANNED(addr, count); nr_pages = min(nr_pages, VEC_SIZE); down_read(¤t->mm->mmap_sem); ret = get_user_pages(current, current->mm, addr, nr_pages, rw == READ, 0, pvec->page, NULL); up_read(¤t->mm->mmap_sem); if (ret < 0) return ERR_PTR(ret); pvec->nr = ret; pvec->idx = 0; } return pvec->page[pvec->idx++]; } /* return a page back to pvec array */ static void blk_unget_page(struct page *page, struct pvec *pvec) { pvec->page[--pvec->idx] = page; } static ssize_t blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs) { struct inode *inode = iocb->ki_filp->f_mapping->host; unsigned blkbits = blksize_bits(bdev_hardsect_size(I_BDEV(inode))); unsigned blocksize_mask = (1 << blkbits) - 1; unsigned long seg = 0; /* iov segment iterator */ unsigned long nvec; /* number of bio vec needed */ unsigned long cur_off; /* offset into current page */ unsigned long cur_len; /* I/O len of current page, up to PAGE_SIZE */ unsigned long addr; /* user iovec address */ size_t count; /* user iovec len */ size_t nbytes = iocb->ki_nbytes = iocb->ki_left; /* total xfer size */ loff_t size; /* size of block device */ struct bio *bio; atomic_t *bio_count = &iocb->ki_bio_count; struct page *page; struct pvec pvec; pvec.nr = 0; pvec.idx = 0; if (pos & blocksize_mask) return -EINVAL; size = i_size_read(inode); if (pos + nbytes > size) { nbytes = size - pos; iocb->ki_left = nbytes; } /* * check first non-zero iov alignment, the remaining * iov alignment is checked inside bio loop below. */ do { addr = (unsigned long) iov[seg].iov_base; count = min(iov[seg].iov_len, nbytes); if (addr & blocksize_mask || count & blocksize_mask) return -EINVAL; } while (!count && ++seg < nr_segs); atomic_set(bio_count, 1); while (nbytes) { /* roughly estimate number of bio vec needed */ nvec = (nbytes + PAGE_SIZE - 1) / PAGE_SIZE; nvec = max(nvec, nr_segs - seg); nvec = min(nvec, (unsigned long) BIO_MAX_PAGES); /* bio_alloc should not fail with GFP_KERNEL flag */ bio = bio_alloc(GFP_KERNEL, nvec); bio->bi_bdev = I_BDEV(inode); bio->bi_end_io = blk_end_aio; bio->bi_private = iocb; bio->bi_sector = pos >> blkbits; same_bio: cur_off = addr & ~PAGE_MASK; cur_len = PAGE_SIZE - cur_off; if (count < cur_len) cur_len = count; page = blk_get_page(addr, count, rw, &pvec); if (unlikely(IS_ERR(page))) goto backout; if (bio_add_page(bio, page, cur_len, cur_off)) { pos += cur_len; addr += cur_len; count -= cur_len; nbytes -= cur_len; if (count) goto same_bio; while (++seg < nr_segs) { addr = (unsigned long) iov[seg].iov_base; count = iov[seg].iov_len; if (!count) continue; if (unlikely(addr & blocksize_mask || count & blocksize_mask)) { page = ERR_PTR(-EINVAL); goto backout; } count = min(count, nbytes); goto same_bio; } } else { blk_unget_page(page, &pvec); } /* bio is ready, submit it */ if (rw == READ) bio_set_pages_dirty(bio); atomic_inc(bio_count); submit_bio(rw, bio); } completion: iocb->ki_left -= nbytes; nbytes = iocb->ki_left; iocb->ki_pos += nbytes; blk_run_address_space(inode->i_mapping); if (atomic_dec_and_test(bio_count)) aio_complete(iocb, nbytes, 0); return -EIOCBQUEUED; backout: /* * back out nbytes count constructed so far for this bio, * we will throw away current bio. */ nbytes += bio->bi_size; bio_release_pages(bio); bio_put(bio); /* * if no bio was submmitted, return the error code. * otherwise, proceed with pending I/O completion. */ if (atomic_read(bio_count) == 1) return PTR_ERR(page); goto completion; } #endif 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_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) { return block_prepare_write(page, from, to, blkdev_get_block); } static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) { return block_commit_write(page, from, to); } /* * 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 kmem_cache * cachep, unsigned long flags) { 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, NULL); err = register_filesystem(&bd_type); if (err) panic("Cannot register bdev pseudo-fs"); bd_mnt = kern_mount(&bd_type); err = PTR_ERR(bd_mnt); 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 list_head *p; long ret = 0; spin_lock(&bdev_lock); list_for_each(p, &all_bdevs) { struct block_device *bdev; bdev = list_entry(p, struct block_device, 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 struct kobject *bdev_get_kobj(struct block_device *bdev) { if (bdev->bd_contains != bdev) return kobject_get(&bdev->bd_part->kobj); else return kobject_get(&bdev->bd_disk->kobj); } static struct kobject *bdev_get_holder(struct block_device *bdev) { if (bdev->bd_contains != bdev) return kobject_get(bdev->bd_part->holder_dir); else return kobject_get(bdev->bd_disk->holder_dir); } 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 = bdev_get_kobj(bdev); if (!bo->sdev) goto fail_put_hdev; bo->hdir = bdev_get_holder(bdev); 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 ret; if (!bo) return -EINVAL; if (!bd_holder_grab_dirs(bdev, bo)) return -EBUSY; ret = add_symlink(bo->sdir, bo->sdev); if (ret == 0) { ret = add_symlink(bo->hdir, bo->hdev); if (ret) del_symlink(bo->sdir, bo->sdev); } if (ret == 0) list_add_tail(&bo->list, &bdev->bd_holder_list); return ret; } /** * 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 res; struct bd_holder *bo, *found; if (!kobj) return -EINVAL; bo = alloc_bd_holder(kobj); if (!bo) return -ENOMEM; mutex_lock(&bdev->bd_mutex); res = bd_claim(bdev, holder); if (res == 0) { found = find_bd_holder(bdev, bo); if (found == NULL) { res = add_bd_holder(bdev, bo); if (res) bd_release(bdev); } } if (res || found) free_bd_holder(bo); mutex_unlock(&bdev->bd_mutex); return res; } /** * 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) { struct bd_holder *bo; if (!kobj) return; mutex_lock(&bdev->bd_mutex); bd_release(bdev); if ((bo = del_bd_holder(bdev, kobj))) free_bd_holder(bo); 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, unsigned 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); /* * 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; if (__invalidate_device(bdev)) printk("VFS: busy inodes on changed media.\n"); if (bdops->revalidate_disk) bdops->revalidate_disk(bdev->bd_disk); if (bdev->bd_disk->minors > 1) bdev->bd_invalidated = 1; 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, mode_t mode, unsigned flags, int for_part); static int __blkdev_put(struct block_device *bdev, 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 module *owner = NULL; struct gendisk *disk; int ret = -ENXIO; int part; file->f_mapping = bdev->bd_inode->i_mapping; lock_kernel(); disk = get_gendisk(bdev->bd_dev, &part); if (!disk) { unlock_kernel(); bdput(bdev); return ret; } owner = disk->fops->owner; mutex_lock_nested(&bdev->bd_mutex, for_part); if (!bdev->bd_openers) { bdev->bd_disk = disk; bdev->bd_contains = bdev; if (!part) { struct backing_dev_info *bdi; if (disk->fops->open) { ret = disk->fops->open(bdev->bd_inode, file); if (ret) goto out_first; } 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 hd_struct *p; struct block_device *whole; whole = bdget_disk(disk, 0); ret = -ENOMEM; if (!whole) goto out_first; BUG_ON(for_part); ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1); if (ret) goto out_first; bdev->bd_contains = whole; p = disk->part[part - 1]; bdev->bd_inode->i_data.backing_dev_info = whole->bd_inode->i_data.backing_dev_info; if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { ret = -ENXIO; goto out_first; } kobject_get(&p->kobj); bdev->bd_part = p; bd_set_size(bdev, (loff_t) p->nr_sects << 9); } } else { put_disk(disk); module_put(owner); if (bdev->bd_contains == bdev) { if (bdev->bd_disk->fops->open) { ret = bdev->bd_disk->fops->open(bdev->bd_inode, file); if (ret) goto out; } 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_first: bdev->bd_disk = NULL; bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; if (bdev != bdev->bd_contains) __blkdev_put(bdev->bd_contains, 1); bdev->bd_contains = NULL; put_disk(disk); module_put(owner); out: mutex_unlock(&bdev->bd_mutex); unlock_kernel(); if (ret) bdput(bdev); return ret; } static int __blkdev_get(struct block_device *bdev, mode_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, mode_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); return res; } static int __blkdev_put(struct block_device *bdev, int for_part) { int ret = 0; struct inode *bd_inode = bdev->bd_inode; 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(bd_inode, NULL); } if (!bdev->bd_openers) { struct module *owner = disk->fops->owner; put_disk(disk); module_put(owner); if (bdev->bd_contains != bdev) { kobject_put(&bdev->bd_part->kobj); 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, 1); return ret; } int blkdev_put(struct block_device *bdev) { return __blkdev_put(bdev, 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); } static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) { return blkdev_ioctl(file->f_mapping->host, file, cmd, arg); } const struct address_space_operations def_blk_aops = { .readpage = blkdev_readpage, .writepage = blkdev_writepage, .sync_page = block_sync_page, .prepare_write = blkdev_prepare_write, .commit_write = blkdev_commit_write, .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 @path 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.dentry->d_inode; error = -ENOTBLK; if (!S_ISBLK(inode->i_mode)) goto fail; error = -EACCES; if (nd.mnt->mnt_flags & MNT_NODEV) goto fail; error = -ENOMEM; bdev = bd_acquire(inode); if (!bdev) goto fail; out: path_release(&nd); return bdev; fail: bdev = ERR_PTR(error); goto out; } /** * 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; mode_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); 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); } 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);