/* * 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/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 <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 intblkdev_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 intblkdev_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_tblkdev_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);} /* * 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){ int ret = 0; if (bdev) ret = filemap_write_and_wait(bdev->bd_inode->i_mapping); return ret;}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 = fsync_super(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 * * This takes the block device bd_mount_sem to make sure no new mounts * happen on bdev until thaw_bdev() is called. * 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 > 0) { bdev->bd_fsfreeze_count++; sb = get_super(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); return sb; } bdev->bd_fsfreeze_count++; down(&bdev->bd_mount_sem); sb = get_super(bdev); if (sb && !(sb->s_flags & MS_RDONLY)) { sb->s_frozen = SB_FREEZE_WRITE; smp_wmb(); __fsync_super(sb); sb->s_frozen = SB_FREEZE_TRANS; smp_wmb(); sync_blockdev(sb->s_bdev); if (sb->s_op->freeze_fs) { error = sb->s_op->freeze_fs(sb); if (error) { printk(KERN_ERR "VFS:Filesystem freeze failed\n"); sb->s_frozen = SB_UNFROZEN; drop_super(sb); up(&bdev->bd_mount_sem); bdev->bd_fsfreeze_count--; mutex_unlock(&bdev->bd_fsfreeze_mutex); return ERR_PTR(error); } } } sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */}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 = 0; mutex_lock(&bdev->bd_fsfreeze_mutex); if (!bdev->bd_fsfreeze_count) { mutex_unlock(&bdev->bd_fsfreeze_mutex); return -EINVAL; } bdev->bd_fsfreeze_count--; if (bdev->bd_fsfreeze_count > 0) { if (sb) drop_super(sb); mutex_unlock(&bdev->bd_fsfreeze_mutex); return 0; } if (sb) { BUG_ON(sb->s_bdev != bdev); if (!(sb->s_flags & MS_RDONLY)) { if (sb->s_op->unfreeze_fs) { error = sb->s_op->unfreeze_fs(sb); if (error) { printk(KERN_ERR "VFS:Filesystem thaw failed\n"); sb->s_frozen = SB_FREEZE_TRANS; bdev->bd_fsfreeze_count++; mutex_unlock(&bdev->bd_fsfreeze_mutex); return error; } } sb->s_frozen = SB_UNFROZEN; smp_wmb(); wake_up(&sb->s_wait_unfrozen); } drop_super(sb); } up(&bdev->bd_mount_sem); 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){ *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); /* 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_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,}; 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"); 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.Lines 1–500 of 1556. 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/* * 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/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 <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); } /* * 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) { int ret = 0; if (bdev) ret = filemap_write_and_wait(bdev->bd_inode->i_mapping); return ret; } 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 = fsync_super(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 * * This takes the block device bd_mount_sem to make sure no new mounts * happen on bdev until thaw_bdev() is called. * 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 > 0) { bdev->bd_fsfreeze_count++; sb = get_super(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); return sb; } bdev->bd_fsfreeze_count++; down(&bdev->bd_mount_sem); sb = get_super(bdev); if (sb && !(sb->s_flags & MS_RDONLY)) { sb->s_frozen = SB_FREEZE_WRITE; smp_wmb(); __fsync_super(sb); sb->s_frozen = SB_FREEZE_TRANS; smp_wmb(); sync_blockdev(sb->s_bdev); if (sb->s_op->freeze_fs) { error = sb->s_op->freeze_fs(sb); if (error) { printk(KERN_ERR "VFS:Filesystem freeze failed\n"); sb->s_frozen = SB_UNFROZEN; drop_super(sb); up(&bdev->bd_mount_sem); bdev->bd_fsfreeze_count--; mutex_unlock(&bdev->bd_fsfreeze_mutex); return ERR_PTR(error); } } } sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ } 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 = 0; mutex_lock(&bdev->bd_fsfreeze_mutex); if (!bdev->bd_fsfreeze_count) { mutex_unlock(&bdev->bd_fsfreeze_mutex); return -EINVAL; } bdev->bd_fsfreeze_count--; if (bdev->bd_fsfreeze_count > 0) { if (sb) drop_super(sb); mutex_unlock(&bdev->bd_fsfreeze_mutex); return 0; } if (sb) { BUG_ON(sb->s_bdev != bdev); if (!(sb->s_flags & MS_RDONLY)) { if (sb->s_op->unfreeze_fs) { error = sb->s_op->unfreeze_fs(sb); if (error) { printk(KERN_ERR "VFS:Filesystem thaw failed\n"); sb->s_frozen = SB_FREEZE_TRANS; bdev->bd_fsfreeze_count++; mutex_unlock(&bdev->bd_fsfreeze_mutex); return error; } } sb->s_frozen = SB_UNFROZEN; smp_wmb(); wake_up(&sb->s_wait_unfrozen); } drop_super(sb); } up(&bdev->bd_mount_sem); 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) { *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); /* 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_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, }; 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"); 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.