diff options
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | fs/block_dev.c | 2277 |
1 files changed, 0 insertions, 2277 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c deleted file mode 100644 index 69bf2fb6f7cd..000000000000 --- a/fs/block_dev.c +++ /dev/null @@ -1,2277 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * linux/fs/block_dev.c - * - * Copyright (C) 1991, 1992 Linus Torvalds - * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE - */ - -#include <linux/init.h> -#include <linux/mm.h> -#include <linux/fcntl.h> -#include <linux/slab.h> -#include <linux/kmod.h> -#include <linux/major.h> -#include <linux/device_cgroup.h> -#include <linux/highmem.h> -#include <linux/blkdev.h> -#include <linux/backing-dev.h> -#include <linux/module.h> -#include <linux/blkpg.h> -#include <linux/magic.h> -#include <linux/dax.h> -#include <linux/buffer_head.h> -#include <linux/swap.h> -#include <linux/pagevec.h> -#include <linux/writeback.h> -#include <linux/mpage.h> -#include <linux/mount.h> -#include <linux/pseudo_fs.h> -#include <linux/uio.h> -#include <linux/namei.h> -#include <linux/log2.h> -#include <linux/cleancache.h> -#include <linux/task_io_accounting_ops.h> -#include <linux/falloc.h> -#include <linux/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); -} - -struct block_device *I_BDEV(struct inode *inode) -{ - return &BDEV_I(inode)->bdev; -} -EXPORT_SYMBOL(I_BDEV); - -static void bdev_write_inode(struct block_device *bdev) -{ - struct inode *inode = bdev->bd_inode; - int ret; - - spin_lock(&inode->i_lock); - while (inode->i_state & I_DIRTY) { - spin_unlock(&inode->i_lock); - ret = write_inode_now(inode, true); - if (ret) { - char name[BDEVNAME_SIZE]; - pr_warn_ratelimited("VFS: Dirty inode writeback failed " - "for block device %s (err=%d).\n", - bdevname(bdev, name), ret); - } - spin_lock(&inode->i_lock); - } - spin_unlock(&inode->i_lock); -} - -/* Kill _all_ buffers and pagecache , dirty or not.. */ -void kill_bdev(struct block_device *bdev) -{ - struct address_space *mapping = bdev->bd_inode->i_mapping; - - if (mapping->nrpages == 0 && mapping->nrexceptional == 0) - return; - - invalidate_bh_lrus(); - truncate_inode_pages(mapping, 0); -} -EXPORT_SYMBOL(kill_bdev); - -/* Invalidate clean unused buffers and pagecache. */ -void invalidate_bdev(struct block_device *bdev) -{ - struct address_space *mapping = bdev->bd_inode->i_mapping; - - if (mapping->nrpages) { - invalidate_bh_lrus(); - lru_add_drain_all(); /* make sure all lru add caches are flushed */ - invalidate_mapping_pages(mapping, 0, -1); - } - /* 99% of the time, we don't need to flush the cleancache on the bdev. - * But, for the strange corners, lets be cautious - */ - cleancache_invalidate_inode(mapping); -} -EXPORT_SYMBOL(invalidate_bdev); - -static void set_init_blocksize(struct block_device *bdev) -{ - unsigned bsize = bdev_logical_block_size(bdev); - loff_t size = i_size_read(bdev->bd_inode); - - while (bsize < PAGE_SIZE) { - if (size & bsize) - break; - bsize <<= 1; - } - bdev->bd_block_size = bsize; - bdev->bd_inode->i_blkbits = blksize_bits(bsize); -} - -int set_blocksize(struct block_device *bdev, int size) -{ - /* Size must be a power of two, and between 512 and PAGE_SIZE */ - if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) - return -EINVAL; - - /* Size cannot be smaller than the size supported by the device */ - if (size < bdev_logical_block_size(bdev)) - return -EINVAL; - - /* Don't change the size if it is same as current */ - if (bdev->bd_block_size != size) { - sync_blockdev(bdev); - bdev->bd_block_size = size; - bdev->bd_inode->i_blkbits = blksize_bits(size); - kill_bdev(bdev); - } - return 0; -} - -EXPORT_SYMBOL(set_blocksize); - -int sb_set_blocksize(struct super_block *sb, int size) -{ - if (set_blocksize(sb->s_bdev, size)) - return 0; - /* If we get here, we know size is power of two - * and it's value is between 512 and PAGE_SIZE */ - sb->s_blocksize = size; - sb->s_blocksize_bits = blksize_bits(size); - return sb->s_blocksize; -} - -EXPORT_SYMBOL(sb_set_blocksize); - -int sb_min_blocksize(struct super_block *sb, int size) -{ - int minsize = bdev_logical_block_size(sb->s_bdev); - if (size < minsize) - size = minsize; - return sb_set_blocksize(sb, size); -} - -EXPORT_SYMBOL(sb_min_blocksize); - -static int -blkdev_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh, int create) -{ - bh->b_bdev = I_BDEV(inode); - bh->b_blocknr = iblock; - set_buffer_mapped(bh); - return 0; -} - -static struct inode *bdev_file_inode(struct file *file) -{ - return file->f_mapping->host; -} - -static unsigned int dio_bio_write_op(struct kiocb *iocb) -{ - unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; - - /* avoid the need for a I/O completion work item */ - if (iocb->ki_flags & IOCB_DSYNC) - op |= REQ_FUA; - return op; -} - -#define DIO_INLINE_BIO_VECS 4 - -static void blkdev_bio_end_io_simple(struct bio *bio) -{ - struct task_struct *waiter = bio->bi_private; - - WRITE_ONCE(bio->bi_private, NULL); - blk_wake_io_task(waiter); -} - -static ssize_t -__blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, - int nr_pages) -{ - struct file *file = iocb->ki_filp; - struct block_device *bdev = I_BDEV(bdev_file_inode(file)); - struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; - loff_t pos = iocb->ki_pos; - bool should_dirty = false; - struct bio bio; - ssize_t ret; - blk_qc_t qc; - - if ((pos | iov_iter_alignment(iter)) & - (bdev_logical_block_size(bdev) - 1)) - return -EINVAL; - - if (nr_pages <= DIO_INLINE_BIO_VECS) - vecs = inline_vecs; - else { - vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), - GFP_KERNEL); - if (!vecs) - return -ENOMEM; - } - - bio_init(&bio, vecs, nr_pages); - bio_set_dev(&bio, bdev); - bio.bi_iter.bi_sector = pos >> 9; - bio.bi_write_hint = iocb->ki_hint; - bio.bi_private = current; - bio.bi_end_io = blkdev_bio_end_io_simple; - bio.bi_ioprio = iocb->ki_ioprio; - - ret = bio_iov_iter_get_pages(&bio, iter); - if (unlikely(ret)) - goto out; - ret = bio.bi_iter.bi_size; - - if (iov_iter_rw(iter) == READ) { - bio.bi_opf = REQ_OP_READ; - if (iter_is_iovec(iter)) - should_dirty = true; - } else { - bio.bi_opf = dio_bio_write_op(iocb); - task_io_account_write(ret); - } - if (iocb->ki_flags & IOCB_HIPRI) - bio_set_polled(&bio, iocb); - - qc = submit_bio(&bio); - for (;;) { - set_current_state(TASK_UNINTERRUPTIBLE); - if (!READ_ONCE(bio.bi_private)) - break; - if (!(iocb->ki_flags & IOCB_HIPRI) || - !blk_poll(bdev_get_queue(bdev), qc, true)) - io_schedule(); - } - __set_current_state(TASK_RUNNING); - - bio_release_pages(&bio, should_dirty); - if (unlikely(bio.bi_status)) - ret = blk_status_to_errno(bio.bi_status); - -out: - if (vecs != inline_vecs) - kfree(vecs); - - bio_uninit(&bio); - - return ret; -} - -struct blkdev_dio { - union { - struct kiocb *iocb; - struct task_struct *waiter; - }; - size_t size; - atomic_t ref; - bool multi_bio : 1; - bool should_dirty : 1; - bool is_sync : 1; - struct bio bio; -}; - -static struct bio_set blkdev_dio_pool; - -static int blkdev_iopoll(struct kiocb *kiocb, bool wait) -{ - struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host); - struct request_queue *q = bdev_get_queue(bdev); - - return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait); -} - -static void blkdev_bio_end_io(struct bio *bio) -{ - struct blkdev_dio *dio = bio->bi_private; - bool should_dirty = dio->should_dirty; - - if (bio->bi_status && !dio->bio.bi_status) - dio->bio.bi_status = bio->bi_status; - - if (!dio->multi_bio || atomic_dec_and_test(&dio->ref)) { - if (!dio->is_sync) { - struct kiocb *iocb = dio->iocb; - ssize_t ret; - - if (likely(!dio->bio.bi_status)) { - ret = dio->size; - iocb->ki_pos += ret; - } else { - ret = blk_status_to_errno(dio->bio.bi_status); - } - - dio->iocb->ki_complete(iocb, ret, 0); - if (dio->multi_bio) - bio_put(&dio->bio); - } else { - struct task_struct *waiter = dio->waiter; - - WRITE_ONCE(dio->waiter, NULL); - blk_wake_io_task(waiter); - } - } - - if (should_dirty) { - bio_check_pages_dirty(bio); - } else { - bio_release_pages(bio, false); - bio_put(bio); - } -} - -static ssize_t -__blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) -{ - struct file *file = iocb->ki_filp; - struct inode *inode = bdev_file_inode(file); - struct block_device *bdev = I_BDEV(inode); - struct blk_plug plug; - struct blkdev_dio *dio; - struct bio *bio; - bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0; - bool is_read = (iov_iter_rw(iter) == READ), is_sync; - loff_t pos = iocb->ki_pos; - blk_qc_t qc = BLK_QC_T_NONE; - int ret = 0; - - if ((pos | iov_iter_alignment(iter)) & - (bdev_logical_block_size(bdev) - 1)) - return -EINVAL; - - bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool); - - dio = container_of(bio, struct blkdev_dio, bio); - dio->is_sync = is_sync = is_sync_kiocb(iocb); - if (dio->is_sync) { - dio->waiter = current; - bio_get(bio); - } else { - dio->iocb = iocb; - } - - dio->size = 0; - dio->multi_bio = false; - dio->should_dirty = is_read && iter_is_iovec(iter); - - /* - * Don't plug for HIPRI/polled IO, as those should go straight - * to issue - */ - if (!is_poll) - blk_start_plug(&plug); - - for (;;) { - bio_set_dev(bio, bdev); - bio->bi_iter.bi_sector = pos >> 9; - bio->bi_write_hint = iocb->ki_hint; - bio->bi_private = dio; - bio->bi_end_io = blkdev_bio_end_io; - bio->bi_ioprio = iocb->ki_ioprio; - - ret = bio_iov_iter_get_pages(bio, iter); - if (unlikely(ret)) { - bio->bi_status = BLK_STS_IOERR; - bio_endio(bio); - break; - } - - if (is_read) { - bio->bi_opf = REQ_OP_READ; - if (dio->should_dirty) - bio_set_pages_dirty(bio); - } else { - bio->bi_opf = dio_bio_write_op(iocb); - task_io_account_write(bio->bi_iter.bi_size); - } - - dio->size += bio->bi_iter.bi_size; - pos += bio->bi_iter.bi_size; - - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); - if (!nr_pages) { - bool polled = false; - - if (iocb->ki_flags & IOCB_HIPRI) { - bio_set_polled(bio, iocb); - polled = true; - } - - qc = submit_bio(bio); - - if (polled) - WRITE_ONCE(iocb->ki_cookie, qc); - break; - } - - if (!dio->multi_bio) { - /* - * AIO needs an extra reference to ensure the dio - * structure which is embedded into the first bio - * stays around. - */ - if (!is_sync) - bio_get(bio); - dio->multi_bio = true; - atomic_set(&dio->ref, 2); - } else { - atomic_inc(&dio->ref); - } - - submit_bio(bio); - bio = bio_alloc(GFP_KERNEL, nr_pages); - } - - if (!is_poll) - blk_finish_plug(&plug); - - if (!is_sync) - return -EIOCBQUEUED; - - for (;;) { - set_current_state(TASK_UNINTERRUPTIBLE); - if (!READ_ONCE(dio->waiter)) - break; - - if (!(iocb->ki_flags & IOCB_HIPRI) || - !blk_poll(bdev_get_queue(bdev), qc, true)) - io_schedule(); - } - __set_current_state(TASK_RUNNING); - - if (!ret) - ret = blk_status_to_errno(dio->bio.bi_status); - if (likely(!ret)) - ret = dio->size; - - bio_put(&dio->bio); - return ret; -} - -static ssize_t -blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) -{ - int nr_pages; - - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES + 1); - if (!nr_pages) - return 0; - if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_PAGES) - return __blkdev_direct_IO_simple(iocb, iter, nr_pages); - - return __blkdev_direct_IO(iocb, iter, min(nr_pages, BIO_MAX_PAGES)); -} - -static __init int blkdev_init(void) -{ - return bioset_init(&blkdev_dio_pool, 4, offsetof(struct blkdev_dio, bio), BIOSET_NEED_BVECS); -} -module_init(blkdev_init); - -int __sync_blockdev(struct block_device *bdev, int wait) -{ - if (!bdev) - return 0; - if (!wait) - return filemap_flush(bdev->bd_inode->i_mapping); - return filemap_write_and_wait(bdev->bd_inode->i_mapping); -} - -/* - * Write out and wait upon all the dirty data associated with a block - * device via its mapping. Does not take the superblock lock. - */ -int sync_blockdev(struct block_device *bdev) -{ - return __sync_blockdev(bdev, 1); -} -EXPORT_SYMBOL(sync_blockdev); - -/* - * Write out and wait upon all dirty data associated with this - * device. Filesystem data as well as the underlying block - * device. Takes the superblock lock. - */ -int fsync_bdev(struct block_device *bdev) -{ - struct super_block *sb = get_super(bdev); - if (sb) { - int res = sync_filesystem(sb); - drop_super(sb); - return res; - } - return sync_blockdev(bdev); -} -EXPORT_SYMBOL(fsync_bdev); - -/** - * freeze_bdev -- lock a filesystem and force it into a consistent state - * @bdev: blockdevice to lock - * - * If a superblock is found on this device, we take the s_umount semaphore - * on it to make sure nobody unmounts until the snapshot creation is done. - * The reference counter (bd_fsfreeze_count) guarantees that only the last - * unfreeze process can unfreeze the frozen filesystem actually when multiple - * freeze requests arrive simultaneously. It counts up in freeze_bdev() and - * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze - * actually. - */ -struct super_block *freeze_bdev(struct block_device *bdev) -{ - struct super_block *sb; - int error = 0; - - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (++bdev->bd_fsfreeze_count > 1) { - /* - * We don't even need to grab a reference - the first call - * to freeze_bdev grab an active reference and only the last - * thaw_bdev drops it. - */ - sb = get_super(bdev); - if (sb) - drop_super(sb); - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return sb; - } - - sb = get_active_super(bdev); - if (!sb) - goto out; - if (sb->s_op->freeze_super) - error = sb->s_op->freeze_super(sb); - else - error = freeze_super(sb); - if (error) { - deactivate_super(sb); - bdev->bd_fsfreeze_count--; - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return ERR_PTR(error); - } - deactivate_super(sb); - out: - sync_blockdev(bdev); - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return sb; /* thaw_bdev releases s->s_umount */ -} -EXPORT_SYMBOL(freeze_bdev); - -/** - * thaw_bdev -- unlock filesystem - * @bdev: blockdevice to unlock - * @sb: associated superblock - * - * Unlocks the filesystem and marks it writeable again after freeze_bdev(). - */ -int thaw_bdev(struct block_device *bdev, struct super_block *sb) -{ - int error = -EINVAL; - - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (!bdev->bd_fsfreeze_count) - goto out; - - error = 0; - if (--bdev->bd_fsfreeze_count > 0) - goto out; - - if (!sb) - goto out; - - if (sb->s_op->thaw_super) - error = sb->s_op->thaw_super(sb); - else - error = thaw_super(sb); - if (error) - bdev->bd_fsfreeze_count++; -out: - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return error; -} -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_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) -{ - return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); -} - -static int blkdev_write_begin(struct file *file, struct address_space *mapping, - loff_t pos, unsigned len, unsigned flags, - struct page **pagep, void **fsdata) -{ - return block_write_begin(mapping, pos, len, flags, pagep, - blkdev_get_block); -} - -static int blkdev_write_end(struct file *file, struct address_space *mapping, - loff_t pos, unsigned len, unsigned copied, - struct page *page, void *fsdata) -{ - int ret; - ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); - - unlock_page(page); - put_page(page); - - return ret; -} - -/* - * private llseek: - * for a block special file file_inode(file)->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 whence) -{ - struct inode *bd_inode = bdev_file_inode(file); - loff_t retval; - - inode_lock(bd_inode); - retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); - inode_unlock(bd_inode); - return retval; -} - -int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) -{ - struct inode *bd_inode = bdev_file_inode(filp); - struct block_device *bdev = I_BDEV(bd_inode); - int error; - - error = file_write_and_wait_range(filp, start, end); - if (error) - return error; - - /* - * There is no need to serialise calls to blkdev_issue_flush with - * i_mutex and doing so causes performance issues with concurrent - * O_SYNC writers to a block device. - */ - error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); - if (error == -EOPNOTSUPP) - error = 0; - - return error; -} -EXPORT_SYMBOL(blkdev_fsync); - -/** - * bdev_read_page() - Start reading a page from a block device - * @bdev: The device to read the page from - * @sector: The offset on the device to read the page to (need not be aligned) - * @page: The page to read - * - * On entry, the page should be locked. It will be unlocked when the page - * has been read. If the block driver implements rw_page synchronously, - * that will be true on exit from this function, but it need not be. - * - * Errors returned by this function are usually "soft", eg out of memory, or - * queue full; callers should try a different route to read this page rather - * than propagate an error back up the stack. - * - * Return: negative errno if an error occurs, 0 if submission was successful. - */ -int bdev_read_page(struct block_device *bdev, sector_t sector, - struct page *page) -{ - const struct block_device_operations *ops = bdev->bd_disk->fops; - int result = -EOPNOTSUPP; - - if (!ops->rw_page || bdev_get_integrity(bdev)) - return result; - - result = blk_queue_enter(bdev->bd_queue, 0); - if (result) - return result; - result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, - REQ_OP_READ); - blk_queue_exit(bdev->bd_queue); - return result; -} -EXPORT_SYMBOL_GPL(bdev_read_page); - -/** - * bdev_write_page() - Start writing a page to a block device - * @bdev: The device to write the page to - * @sector: The offset on the device to write the page to (need not be aligned) - * @page: The page to write - * @wbc: The writeback_control for the write - * - * On entry, the page should be locked and not currently under writeback. - * On exit, if the write started successfully, the page will be unlocked and - * under writeback. If the write failed already (eg the driver failed to - * queue the page to the device), the page will still be locked. If the - * caller is a ->writepage implementation, it will need to unlock the page. - * - * Errors returned by this function are usually "soft", eg out of memory, or - * queue full; callers should try a different route to write this page rather - * than propagate an error back up the stack. - * - * Return: negative errno if an error occurs, 0 if submission was successful. - */ -int bdev_write_page(struct block_device *bdev, sector_t sector, - struct page *page, struct writeback_control *wbc) -{ - int result; - const struct block_device_operations *ops = bdev->bd_disk->fops; - - if (!ops->rw_page || bdev_get_integrity(bdev)) - return -EOPNOTSUPP; - result = blk_queue_enter(bdev->bd_queue, 0); - if (result) - return result; - - set_page_writeback(page); - result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, - REQ_OP_WRITE); - if (result) { - end_page_writeback(page); - } else { - clean_page_buffers(page); - unlock_page(page); - } - blk_queue_exit(bdev->bd_queue); - return result; -} -EXPORT_SYMBOL_GPL(bdev_write_page); - -/* - * 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_free_inode(struct inode *inode) -{ - kmem_cache_free(bdev_cachep, BDEV_I(inode)); -} - -static void init_once(void *foo) -{ - struct bdev_inode *ei = (struct bdev_inode *) foo; - struct block_device *bdev = &ei->bdev; - - memset(bdev, 0, sizeof(*bdev)); - mutex_init(&bdev->bd_mutex); - INIT_LIST_HEAD(&bdev->bd_list); -#ifdef CONFIG_SYSFS - INIT_LIST_HEAD(&bdev->bd_holder_disks); -#endif - bdev->bd_bdi = &noop_backing_dev_info; - inode_init_once(&ei->vfs_inode); - /* Initialize mutex for freeze. */ - mutex_init(&bdev->bd_fsfreeze_mutex); -} - -static void bdev_evict_inode(struct inode *inode) -{ - struct block_device *bdev = &BDEV_I(inode)->bdev; - truncate_inode_pages_final(&inode->i_data); - invalidate_inode_buffers(inode); /* is it needed here? */ - clear_inode(inode); - spin_lock(&bdev_lock); - list_del_init(&bdev->bd_list); - spin_unlock(&bdev_lock); - /* Detach inode from wb early as bdi_put() may free bdi->wb */ - inode_detach_wb(inode); - if (bdev->bd_bdi != &noop_backing_dev_info) { - bdi_put(bdev->bd_bdi); - bdev->bd_bdi = &noop_backing_dev_info; - } -} - -static const struct super_operations bdev_sops = { - .statfs = simple_statfs, - .alloc_inode = bdev_alloc_inode, - .free_inode = bdev_free_inode, - .drop_inode = generic_delete_inode, - .evict_inode = bdev_evict_inode, -}; - -static int bd_init_fs_context(struct fs_context *fc) -{ - struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); - if (!ctx) - return -ENOMEM; - fc->s_iflags |= SB_I_CGROUPWB; - ctx->ops = &bdev_sops; - return 0; -} - -static struct file_system_type bd_type = { - .name = "bdev", - .init_fs_context = bd_init_fs_context, - .kill_sb = kill_anon_super, -}; - -struct super_block *blockdev_superblock __read_mostly; -EXPORT_SYMBOL_GPL(blockdev_superblock); - -void __init bdev_cache_init(void) -{ - int err; - static struct vfsmount *bd_mnt; - - bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), - 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), - init_once); - err = register_filesystem(&bd_type); - if (err) - panic("Cannot register bdev pseudo-fs"); - bd_mnt = kern_mount(&bd_type); - if (IS_ERR(bd_mnt)) - panic("Cannot create bdev pseudo-fs"); - blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ -} - -/* - * 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); - -/* - * If there is a bdev inode for this device, unhash it so that it gets evicted - * as soon as last inode reference is dropped. - */ -void bdev_unhash_inode(dev_t dev) -{ - struct inode *inode; - - inode = ilookup5(blockdev_superblock, hash(dev), bdev_test, &dev); - if (inode) { - remove_inode_hash(inode); - iput(inode); - } -} - -struct block_device *bdget(dev_t dev) -{ - struct block_device *bdev; - struct inode *inode; - - inode = iget5_locked(blockdev_superblock, hash(dev), - bdev_test, bdev_set, &dev); - - if (!inode) - return NULL; - - bdev = &BDEV_I(inode)->bdev; - - if (inode->i_state & I_NEW) { - bdev->bd_contains = NULL; - bdev->bd_super = NULL; - bdev->bd_inode = inode; - bdev->bd_block_size = i_blocksize(inode); - 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); - spin_lock(&bdev_lock); - list_add(&bdev->bd_list, &all_bdevs); - spin_unlock(&bdev_lock); - unlock_new_inode(inode); - } - return bdev; -} - -EXPORT_SYMBOL(bdget); - -/** - * bdgrab -- Grab a reference to an already referenced block device - * @bdev: Block device to grab a reference to. - */ -struct block_device *bdgrab(struct block_device *bdev) -{ - ihold(bdev->bd_inode); - return bdev; -} -EXPORT_SYMBOL(bdgrab); - -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 && !inode_unhashed(bdev->bd_inode)) { - bdgrab(bdev); - spin_unlock(&bdev_lock); - return bdev; - } - spin_unlock(&bdev_lock); - - /* - * i_bdev references block device inode that was already shut down - * (corresponding device got removed). Remove the reference and look - * up block device inode again just in case new device got - * reestablished under the same device number. - */ - if (bdev) - bd_forget(inode); - - bdev = bdget(inode->i_rdev); - if (bdev) { - spin_lock(&bdev_lock); - if (!inode->i_bdev) { - /* - * We take an additional reference to bd_inode, - * and it's released in clear_inode() of inode. - * So, we can access it via ->i_mapping always - * without igrab(). - */ - bdgrab(bdev); - inode->i_bdev = bdev; - inode->i_mapping = bdev->bd_inode->i_mapping; - } - 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 (!sb_is_blkdev_sb(inode->i_sb)) - bdev = inode->i_bdev; - inode->i_bdev = NULL; - inode->i_mapping = &inode->i_data; - spin_unlock(&bdev_lock); - - if (bdev) - bdput(bdev); -} - -/** - * bd_may_claim - test whether a block device can be claimed - * @bdev: block device of interest - * @whole: whole block device containing @bdev, may equal @bdev - * @holder: holder trying to claim @bdev - * - * Test whether @bdev can be claimed by @holder. - * - * CONTEXT: - * spin_lock(&bdev_lock). - * - * RETURNS: - * %true if @bdev can be claimed, %false otherwise. - */ -static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, - void *holder) -{ - if (bdev->bd_holder == holder) - return true; /* already a holder */ - else if (bdev->bd_holder != NULL) - return false; /* held by someone else */ - else if (whole == bdev) - return true; /* is a whole device which isn't held */ - - else if (whole->bd_holder == bd_may_claim) - return true; /* is a partition of a device that is being partitioned */ - else if (whole->bd_holder != NULL) - return false; /* is a partition of a held device */ - else - return true; /* is a partition of an un-held device */ -} - -/** - * bd_prepare_to_claim - prepare to claim a block device - * @bdev: block device of interest - * @whole: the whole device containing @bdev, may equal @bdev - * @holder: holder trying to claim @bdev - * - * Prepare to claim @bdev. This function fails if @bdev is already - * claimed by another holder and waits if another claiming is in - * progress. This function doesn't actually claim. On successful - * return, the caller has ownership of bd_claiming and bd_holder[s]. - * - * CONTEXT: - * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab - * it multiple times. - * - * RETURNS: - * 0 if @bdev can be claimed, -EBUSY otherwise. - */ -static int bd_prepare_to_claim(struct block_device *bdev, - struct block_device *whole, void *holder) -{ -retry: - /* if someone else claimed, fail */ - if (!bd_may_claim(bdev, whole, holder)) - return -EBUSY; - - /* if claiming is already in progress, wait for it to finish */ - if (whole->bd_claiming) { - wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); - DEFINE_WAIT(wait); - - prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); - spin_unlock(&bdev_lock); - schedule(); - finish_wait(wq, &wait); - spin_lock(&bdev_lock); - goto retry; - } - - /* yay, all mine */ - return 0; -} - -static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno) -{ - struct gendisk *disk = get_gendisk(bdev->bd_dev, partno); - - if (!disk) - return NULL; - /* - * Now that we hold gendisk reference we make sure bdev we looked up is - * not stale. If it is, it means device got removed and created before - * we looked up gendisk and we fail open in such case. Associating - * unhashed bdev with newly created gendisk could lead to two bdevs - * (and thus two independent caches) being associated with one device - * which is bad. - */ - if (inode_unhashed(bdev->bd_inode)) { - put_disk_and_module(disk); - return NULL; - } - return disk; -} - -/** - * bd_start_claiming - start claiming a block device - * @bdev: block device of interest - * @holder: holder trying to claim @bdev - * - * @bdev is about to be opened exclusively. Check @bdev can be opened - * exclusively and mark that an exclusive open is in progress. Each - * successful call to this function must be matched with a call to - * either bd_finish_claiming() or bd_abort_claiming() (which do not - * fail). - * - * This function is used to gain exclusive access to the block device - * without actually causing other exclusive open attempts to fail. It - * should be used when the open sequence itself requires exclusive - * access but may subsequently fail. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Pointer to the block device containing @bdev on success, ERR_PTR() - * value on failure. - */ -struct block_device *bd_start_claiming(struct block_device *bdev, void *holder) -{ - struct gendisk *disk; - struct block_device *whole; - int partno, err; - - might_sleep(); - - /* - * @bdev might not have been initialized properly yet, look up - * and grab the outer block device the hard way. - */ - disk = bdev_get_gendisk(bdev, &partno); - if (!disk) - return ERR_PTR(-ENXIO); - - /* - * Normally, @bdev should equal what's returned from bdget_disk() - * if partno is 0; however, some drivers (floppy) use multiple - * bdev's for the same physical device and @bdev may be one of the - * aliases. Keep @bdev if partno is 0. This means claimer - * tracking is broken for those devices but it has always been that - * way. - */ - if (partno) - whole = bdget_disk(disk, 0); - else - whole = bdgrab(bdev); - - put_disk_and_module(disk); - if (!whole) - return ERR_PTR(-ENOMEM); - - /* prepare to claim, if successful, mark claiming in progress */ - spin_lock(&bdev_lock); - - err = bd_prepare_to_claim(bdev, whole, holder); - if (err == 0) { - whole->bd_claiming = holder; - spin_unlock(&bdev_lock); - return whole; - } else { - spin_unlock(&bdev_lock); - bdput(whole); - return ERR_PTR(err); - } -} -EXPORT_SYMBOL(bd_start_claiming); - -static void bd_clear_claiming(struct block_device *whole, void *holder) -{ - lockdep_assert_held(&bdev_lock); - /* tell others that we're done */ - BUG_ON(whole->bd_claiming != holder); - whole->bd_claiming = NULL; - wake_up_bit(&whole->bd_claiming, 0); -} - -/** - * bd_finish_claiming - finish claiming of a block device - * @bdev: block device of interest - * @whole: whole block device (returned from bd_start_claiming()) - * @holder: holder that has claimed @bdev - * - * Finish exclusive open of a block device. Mark the device as exlusively - * open by the holder and wake up all waiters for exclusive open to finish. - */ -void bd_finish_claiming(struct block_device *bdev, struct block_device *whole, - void *holder) -{ - spin_lock(&bdev_lock); - BUG_ON(!bd_may_claim(bdev, whole, holder)); - /* - * Note that for a whole device bd_holders will be incremented twice, - * and bd_holder will be set to bd_may_claim before being set to holder - */ - whole->bd_holders++; - whole->bd_holder = bd_may_claim; - bdev->bd_holders++; - bdev->bd_holder = holder; - bd_clear_claiming(whole, holder); - spin_unlock(&bdev_lock); -} -EXPORT_SYMBOL(bd_finish_claiming); - -/** - * bd_abort_claiming - abort claiming of a block device - * @bdev: block device of interest - * @whole: whole block device (returned from bd_start_claiming()) - * @holder: holder that has claimed @bdev - * - * Abort claiming of a block device when the exclusive open failed. This can be - * also used when exclusive open is not actually desired and we just needed - * to block other exclusive openers for a while. - */ -void bd_abort_claiming(struct block_device *bdev, struct block_device *whole, - void *holder) -{ - spin_lock(&bdev_lock); - bd_clear_claiming(whole, holder); - spin_unlock(&bdev_lock); -} -EXPORT_SYMBOL(bd_abort_claiming); - -#ifdef CONFIG_SYSFS -struct bd_holder_disk { - struct list_head list; - struct gendisk *disk; - int refcnt; -}; - -static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, - struct gendisk *disk) -{ - struct bd_holder_disk *holder; - - list_for_each_entry(holder, &bdev->bd_holder_disks, list) - if (holder->disk == disk) - return holder; - return NULL; -} - -static int add_symlink(struct kobject *from, struct kobject *to) -{ - return sysfs_create_link(from, to, kobject_name(to)); -} - -static void del_symlink(struct kobject *from, struct kobject *to) -{ - sysfs_remove_link(from, kobject_name(to)); -} - -/** - * bd_link_disk_holder - create symlinks between holding disk and slave bdev - * @bdev: the claimed slave bdev - * @disk: the holding disk - * - * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. - * - * This functions creates the following sysfs symlinks. - * - * - from "slaves" directory of the holder @disk to the claimed @bdev - * - from "holders" directory of the @bdev to the holder @disk - * - * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is - * passed to bd_link_disk_holder(), then: - * - * /sys/block/dm-0/slaves/sda --> /sys/block/sda - * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 - * - * The caller must have claimed @bdev before calling this function and - * ensure that both @bdev and @disk are valid during the creation and - * lifetime of these symlinks. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * 0 on success, -errno on failure. - */ -int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) -{ - struct bd_holder_disk *holder; - int ret = 0; - - mutex_lock(&bdev->bd_mutex); - - WARN_ON_ONCE(!bdev->bd_holder); - - /* FIXME: remove the following once add_disk() handles errors */ - if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) - goto out_unlock; - - holder = bd_find_holder_disk(bdev, disk); - if (holder) { - holder->refcnt++; - goto out_unlock; - } - - holder = kzalloc(sizeof(*holder), GFP_KERNEL); - if (!holder) { - ret = -ENOMEM; - goto out_unlock; - } - - INIT_LIST_HEAD(&holder->list); - holder->disk = disk; - holder->refcnt = 1; - - ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); - if (ret) - goto out_free; - - ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); - if (ret) - goto out_del; - /* - * bdev could be deleted beneath us which would implicitly destroy - * the holder directory. Hold on to it. - */ - kobject_get(bdev->bd_part->holder_dir); - - list_add(&holder->list, &bdev->bd_holder_disks); - goto out_unlock; - -out_del: - del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); -out_free: - kfree(holder); -out_unlock: - mutex_unlock(&bdev->bd_mutex); - return ret; -} -EXPORT_SYMBOL_GPL(bd_link_disk_holder); - -/** - * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() - * @bdev: the calimed slave bdev - * @disk: the holding disk - * - * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. - * - * CONTEXT: - * Might sleep. - */ -void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) -{ - struct bd_holder_disk *holder; - - mutex_lock(&bdev->bd_mutex); - - holder = bd_find_holder_disk(bdev, disk); - - if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { - del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); - del_symlink(bdev->bd_part->holder_dir, - &disk_to_dev(disk)->kobj); - kobject_put(bdev->bd_part->holder_dir); - list_del_init(&holder->list); - kfree(holder); - } - - mutex_unlock(&bdev->bd_mutex); -} -EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); -#endif - -/** - * flush_disk - invalidates all buffer-cache entries on a disk - * - * @bdev: struct block device to be flushed - * @kill_dirty: flag to guide handling of dirty inodes - * - * Invalidates all buffer-cache entries on a disk. It should be called - * when a disk has been changed -- either by a media change or online - * resize. - */ -static void flush_disk(struct block_device *bdev, bool kill_dirty) -{ - if (__invalidate_device(bdev, kill_dirty)) { - printk(KERN_WARNING "VFS: busy inodes on changed media or " - "resized disk %s\n", - bdev->bd_disk ? bdev->bd_disk->disk_name : ""); - } - 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. - * @verbose: if %true log a message about a size change if there is any - * - * This routine checks to see if the bdev size does not match the disk size - * and adjusts it if it differs. When shrinking the bdev size, its all caches - * are freed. - */ -static void check_disk_size_change(struct gendisk *disk, - struct block_device *bdev, bool verbose) -{ - 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) { - if (verbose) { - printk(KERN_INFO - "%s: detected capacity change from %lld to %lld\n", - disk->disk_name, bdev_size, disk_size); - } - i_size_write(bdev->bd_inode, disk_size); - if (bdev_size > disk_size) - flush_disk(bdev, false); - } - bdev->bd_invalidated = 0; -} - -/** - * 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) -{ - int ret = 0; - - if (disk->fops->revalidate_disk) - ret = disk->fops->revalidate_disk(disk); - - /* - * Hidden disks don't have associated bdev so there's no point in - * revalidating it. - */ - if (!(disk->flags & GENHD_FL_HIDDEN)) { - struct block_device *bdev = bdget_disk(disk, 0); - - if (!bdev) - return ret; - - mutex_lock(&bdev->bd_mutex); - check_disk_size_change(disk, bdev, ret == 0); - mutex_unlock(&bdev->bd_mutex); - bdput(bdev); - } - return ret; -} -EXPORT_SYMBOL(revalidate_disk); - -/* - * This routine checks whether a removable media has been changed, - * and invalidates all buffer-cache-entries in that case. This - * is a relatively slow routine, so we have to try to minimize using - * it. Thus it is called only upon a 'mount' or 'open'. This - * is the best way of combining speed and utility, I think. - * People changing diskettes in the middle of an operation deserve - * to lose :-) - */ -int check_disk_change(struct block_device *bdev) -{ - struct gendisk *disk = bdev->bd_disk; - const struct block_device_operations *bdops = disk->fops; - unsigned int events; - - events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | - DISK_EVENT_EJECT_REQUEST); - if (!(events & DISK_EVENT_MEDIA_CHANGE)) - return 0; - - flush_disk(bdev, true); - if (bdops->revalidate_disk) - bdops->revalidate_disk(bdev->bd_disk); - return 1; -} - -EXPORT_SYMBOL(check_disk_change); - -void bd_set_size(struct block_device *bdev, loff_t size) -{ - inode_lock(bdev->bd_inode); - i_size_write(bdev->bd_inode, size); - inode_unlock(bdev->bd_inode); -} -EXPORT_SYMBOL(bd_set_size); - -static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); - -int bdev_disk_changed(struct block_device *bdev, bool invalidate) -{ - struct gendisk *disk = bdev->bd_disk; - int ret; - - lockdep_assert_held(&bdev->bd_mutex); - -rescan: - ret = blk_drop_partitions(disk, bdev); - if (ret) - return ret; - - if (invalidate) - set_capacity(disk, 0); - else if (disk->fops->revalidate_disk) - disk->fops->revalidate_disk(disk); - - check_disk_size_change(disk, bdev, !invalidate); - - if (get_capacity(disk)) { - ret = blk_add_partitions(disk, bdev); - if (ret == -EAGAIN) - goto rescan; - } else if (invalidate) { - /* - * Tell userspace that the media / partition table may have - * changed. - */ - kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE); - } - - return ret; -} -/* - * Only exported for for loop and dasd for historic reasons. Don't use in new - * code! - */ -EXPORT_SYMBOL_GPL(bdev_disk_changed); - -/* - * bd_mutex locking: - * - * mutex_lock(part->bd_mutex) - * mutex_lock_nested(whole->bd_mutex, 1) - */ - -static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) -{ - struct gendisk *disk; - int ret; - int partno; - int perm = 0; - bool first_open = false; - - if (mode & FMODE_READ) - perm |= MAY_READ; - if (mode & FMODE_WRITE) - perm |= MAY_WRITE; - /* - * hooks: /n/, see "layering violations". - */ - if (!for_part) { - ret = devcgroup_inode_permission(bdev->bd_inode, perm); - if (ret != 0) { - bdput(bdev); - return ret; - } - } - - restart: - - ret = -ENXIO; - disk = bdev_get_gendisk(bdev, &partno); - if (!disk) - goto out; - - disk_block_events(disk); - mutex_lock_nested(&bdev->bd_mutex, for_part); - if (!bdev->bd_openers) { - first_open = true; - bdev->bd_disk = disk; - bdev->bd_queue = disk->queue; - bdev->bd_contains = bdev; - bdev->bd_partno = partno; - - if (!partno) { - ret = -ENXIO; - bdev->bd_part = disk_get_part(disk, partno); - if (!bdev->bd_part) - goto out_clear; - - ret = 0; - if (disk->fops->open) { - ret = disk->fops->open(bdev, mode); - if (ret == -ERESTARTSYS) { - /* Lost a race with 'disk' being - * deleted, try again. - * See md.c - */ - disk_put_part(bdev->bd_part); - bdev->bd_part = NULL; - bdev->bd_disk = NULL; - bdev->bd_queue = NULL; - mutex_unlock(&bdev->bd_mutex); - disk_unblock_events(disk); - put_disk_and_module(disk); - goto restart; - } - } - - if (!ret) { - bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); - set_init_blocksize(bdev); - } - - /* - * If the device is invalidated, rescan partition - * if open succeeded or failed with -ENOMEDIUM. - * The latter is necessary to prevent ghost - * partitions on a removed medium. - */ - if (bdev->bd_invalidated && - (!ret || ret == -ENOMEDIUM)) - bdev_disk_changed(bdev, ret == -ENOMEDIUM); - - if (ret) - goto out_clear; - } else { - struct block_device *whole; - whole = bdget_disk(disk, 0); - ret = -ENOMEM; - if (!whole) - goto out_clear; - BUG_ON(for_part); - ret = __blkdev_get(whole, mode, 1); - if (ret) - goto out_clear; - bdev->bd_contains = whole; - bdev->bd_part = disk_get_part(disk, partno); - if (!(disk->flags & GENHD_FL_UP) || - !bdev->bd_part || !bdev->bd_part->nr_sects) { - ret = -ENXIO; - goto out_clear; - } - bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); - set_init_blocksize(bdev); - } - - if (bdev->bd_bdi == &noop_backing_dev_info) - bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info); - } else { - if (bdev->bd_contains == bdev) { - ret = 0; - if (bdev->bd_disk->fops->open) - ret = bdev->bd_disk->fops->open(bdev, mode); - /* the same as first opener case, read comment there */ - if (bdev->bd_invalidated && - (!ret || ret == -ENOMEDIUM)) - bdev_disk_changed(bdev, ret == -ENOMEDIUM); - if (ret) - goto out_unlock_bdev; - } - } - bdev->bd_openers++; - if (for_part) - bdev->bd_part_count++; - mutex_unlock(&bdev->bd_mutex); - disk_unblock_events(disk); - /* only one opener holds refs to the module and disk */ - if (!first_open) - put_disk_and_module(disk); - return 0; - - out_clear: - disk_put_part(bdev->bd_part); - bdev->bd_disk = NULL; - bdev->bd_part = NULL; - bdev->bd_queue = NULL; - if (bdev != bdev->bd_contains) - __blkdev_put(bdev->bd_contains, mode, 1); - bdev->bd_contains = NULL; - out_unlock_bdev: - mutex_unlock(&bdev->bd_mutex); - disk_unblock_events(disk); - put_disk_and_module(disk); - out: - bdput(bdev); - - return ret; -} - -/** - * blkdev_get - open a block device - * @bdev: block_device to open - * @mode: FMODE_* mask - * @holder: exclusive holder identifier - * - * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is - * open with exclusive access. Specifying %FMODE_EXCL with %NULL - * @holder is invalid. Exclusive opens may nest for the same @holder. - * - * On success, the reference count of @bdev is unchanged. On failure, - * @bdev is put. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * 0 on success, -errno on failure. - */ -int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) -{ - struct block_device *whole = NULL; - int res; - - WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); - - if ((mode & FMODE_EXCL) && holder) { - whole = bd_start_claiming(bdev, holder); - if (IS_ERR(whole)) { - bdput(bdev); - return PTR_ERR(whole); - } - } - - res = __blkdev_get(bdev, mode, 0); - - if (whole) { - struct gendisk *disk = whole->bd_disk; - - /* finish claiming */ - mutex_lock(&bdev->bd_mutex); - if (!res) - bd_finish_claiming(bdev, whole, holder); - else - bd_abort_claiming(bdev, whole, holder); - /* - * Block event polling for write claims if requested. Any - * write holder makes the write_holder state stick until - * all are released. This is good enough and tracking - * individual writeable reference is too fragile given the - * way @mode is used in blkdev_get/put(). - */ - if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && - (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { - bdev->bd_write_holder = true; - disk_block_events(disk); - } - - mutex_unlock(&bdev->bd_mutex); - bdput(whole); - } - - return res; -} -EXPORT_SYMBOL(blkdev_get); - -/** - * blkdev_get_by_path - open a block device by name - * @path: path to the block device to open - * @mode: FMODE_* mask - * @holder: exclusive holder identifier - * - * Open the blockdevice described by the device file at @path. @mode - * and @holder are identical to blkdev_get(). - * - * On success, the returned block_device has reference count of one. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Pointer to block_device on success, ERR_PTR(-errno) on failure. - */ -struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, - void *holder) -{ - struct block_device *bdev; - int err; - - bdev = lookup_bdev(path); - if (IS_ERR(bdev)) - return bdev; - - err = blkdev_get(bdev, mode, holder); - if (err) - return ERR_PTR(err); - - if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { - blkdev_put(bdev, mode); - return ERR_PTR(-EACCES); - } - - return bdev; -} -EXPORT_SYMBOL(blkdev_get_by_path); - -/** - * blkdev_get_by_dev - open a block device by device number - * @dev: device number of block device to open - * @mode: FMODE_* mask - * @holder: exclusive holder identifier - * - * Open the blockdevice described by device number @dev. @mode and - * @holder are identical to blkdev_get(). - * - * Use it ONLY if you really do not have anything better - i.e. when - * you are behind a truly sucky interface and all you are given is a - * device number. _Never_ to be used for internal purposes. If you - * ever need it - reconsider your API. - * - * On success, the returned block_device has reference count of one. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Pointer to block_device on success, ERR_PTR(-errno) on failure. - */ -struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) -{ - struct block_device *bdev; - int err; - - bdev = bdget(dev); - if (!bdev) - return ERR_PTR(-ENOMEM); - - err = blkdev_get(bdev, mode, holder); - if (err) - return ERR_PTR(err); - - return bdev; -} -EXPORT_SYMBOL(blkdev_get_by_dev); - -static int blkdev_open(struct inode * inode, struct file * filp) -{ - struct block_device *bdev; - - /* - * Preserve backwards compatibility and allow large file access - * even if userspace doesn't ask for it explicitly. Some mkfs - * binary needs it. We might want to drop this workaround - * during an unstable branch. - */ - filp->f_flags |= O_LARGEFILE; - - filp->f_mode |= FMODE_NOWAIT; - - if (filp->f_flags & O_NDELAY) - filp->f_mode |= FMODE_NDELAY; - if (filp->f_flags & O_EXCL) - filp->f_mode |= FMODE_EXCL; - if ((filp->f_flags & O_ACCMODE) == 3) - filp->f_mode |= FMODE_WRITE_IOCTL; - - bdev = bd_acquire(inode); - if (bdev == NULL) - return -ENOMEM; - - filp->f_mapping = bdev->bd_inode->i_mapping; - filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); - - return blkdev_get(bdev, filp->f_mode, filp); -} - -static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) -{ - struct gendisk *disk = bdev->bd_disk; - struct block_device *victim = NULL; - - mutex_lock_nested(&bdev->bd_mutex, for_part); - if (for_part) - bdev->bd_part_count--; - - if (!--bdev->bd_openers) { - WARN_ON_ONCE(bdev->bd_holders); - sync_blockdev(bdev); - kill_bdev(bdev); - - bdev_write_inode(bdev); - } - if (bdev->bd_contains == bdev) { - if (disk->fops->release) - disk->fops->release(disk, mode); - } - if (!bdev->bd_openers) { - disk_put_part(bdev->bd_part); - bdev->bd_part = NULL; - bdev->bd_disk = NULL; - if (bdev != bdev->bd_contains) - victim = bdev->bd_contains; - bdev->bd_contains = NULL; - - put_disk_and_module(disk); - } - mutex_unlock(&bdev->bd_mutex); - bdput(bdev); - if (victim) - __blkdev_put(victim, mode, 1); -} - -void blkdev_put(struct block_device *bdev, fmode_t mode) -{ - mutex_lock(&bdev->bd_mutex); - - if (mode & FMODE_EXCL) { - bool bdev_free; - - /* - * Release a claim on the device. The holder fields - * are protected with bdev_lock. bd_mutex is to - * synchronize disk_holder unlinking. - */ - spin_lock(&bdev_lock); - - WARN_ON_ONCE(--bdev->bd_holders < 0); - WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); - - /* bd_contains might point to self, check in a separate step */ - if ((bdev_free = !bdev->bd_holders)) - bdev->bd_holder = NULL; - if (!bdev->bd_contains->bd_holders) - bdev->bd_contains->bd_holder = NULL; - - spin_unlock(&bdev_lock); - - /* - * If this was the last claim, remove holder link and - * unblock evpoll if it was a write holder. - */ - if (bdev_free && bdev->bd_write_holder) { - disk_unblock_events(bdev->bd_disk); - bdev->bd_write_holder = false; - } - } - - /* - * Trigger event checking and tell drivers to flush MEDIA_CHANGE - * event. This is to ensure detection of media removal commanded - * from userland - e.g. eject(1). - */ - disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); - - mutex_unlock(&bdev->bd_mutex); - - __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(bdev_file_inode(filp)); - blkdev_put(bdev, filp->f_mode); - return 0; -} - -static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) -{ - struct block_device *bdev = I_BDEV(bdev_file_inode(file)); - fmode_t mode = file->f_mode; - - /* - * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have - * to updated it before every ioctl. - */ - if (file->f_flags & O_NDELAY) - mode |= FMODE_NDELAY; - else - mode &= ~FMODE_NDELAY; - - return blkdev_ioctl(bdev, mode, cmd, arg); -} - -/* - * Write data to the block device. Only intended for the block device itself - * and the raw driver which basically is a fake block device. - * - * Does not take i_mutex for the write and thus is not for general purpose - * use. - */ -ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) -{ - struct file *file = iocb->ki_filp; - struct inode *bd_inode = bdev_file_inode(file); - loff_t size = i_size_read(bd_inode); - struct blk_plug plug; - ssize_t ret; - - if (bdev_read_only(I_BDEV(bd_inode))) - return -EPERM; - - if (IS_SWAPFILE(bd_inode)) - return -ETXTBSY; - - if (!iov_iter_count(from)) - return 0; - - if (iocb->ki_pos >= size) - return -ENOSPC; - - if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) - return -EOPNOTSUPP; - - iov_iter_truncate(from, size - iocb->ki_pos); - - blk_start_plug(&plug); - ret = __generic_file_write_iter(iocb, from); - if (ret > 0) - ret = generic_write_sync(iocb, ret); - blk_finish_plug(&plug); - return ret; -} -EXPORT_SYMBOL_GPL(blkdev_write_iter); - -ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) -{ - struct file *file = iocb->ki_filp; - struct inode *bd_inode = bdev_file_inode(file); - loff_t size = i_size_read(bd_inode); - loff_t pos = iocb->ki_pos; - - if (pos >= size) - return 0; - - size -= pos; - iov_iter_truncate(to, size); - return generic_file_read_iter(iocb, to); -} -EXPORT_SYMBOL_GPL(blkdev_read_iter); - -/* - * Try to release a page associated with block device when the system - * is under memory pressure. - */ -static int blkdev_releasepage(struct page *page, gfp_t wait) -{ - struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; - - if (super && super->s_op->bdev_try_to_free_page) - return super->s_op->bdev_try_to_free_page(super, page, wait); - - return try_to_free_buffers(page); -} - -static int blkdev_writepages(struct address_space *mapping, - struct writeback_control *wbc) -{ - return generic_writepages(mapping, wbc); -} - -static const struct address_space_operations def_blk_aops = { - .readpage = blkdev_readpage, - .readpages = blkdev_readpages, - .writepage = blkdev_writepage, - .write_begin = blkdev_write_begin, - .write_end = blkdev_write_end, - .writepages = blkdev_writepages, - .releasepage = blkdev_releasepage, - .direct_IO = blkdev_direct_IO, - .migratepage = buffer_migrate_page_norefs, - .is_dirty_writeback = buffer_check_dirty_writeback, -}; - -#define BLKDEV_FALLOC_FL_SUPPORTED \ - (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ - FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) - -static long blkdev_fallocate(struct file *file, int mode, loff_t start, - loff_t len) -{ - struct block_device *bdev = I_BDEV(bdev_file_inode(file)); - struct address_space *mapping; - loff_t end = start + len - 1; - loff_t isize; - int error; - - /* Fail if we don't recognize the flags. */ - if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) - return -EOPNOTSUPP; - - /* Don't go off the end of the device. */ - isize = i_size_read(bdev->bd_inode); - if (start >= isize) - return -EINVAL; - if (end >= isize) { - if (mode & FALLOC_FL_KEEP_SIZE) { - len = isize - start; - end = start + len - 1; - } else - return -EINVAL; - } - - /* - * Don't allow IO that isn't aligned to logical block size. - */ - if ((start | len) & (bdev_logical_block_size(bdev) - 1)) - return -EINVAL; - - /* Invalidate the page cache, including dirty pages. */ - mapping = bdev->bd_inode->i_mapping; - truncate_inode_pages_range(mapping, start, end); - - switch (mode) { - case FALLOC_FL_ZERO_RANGE: - case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: - error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, - GFP_KERNEL, BLKDEV_ZERO_NOUNMAP); - break; - case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: - error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, - GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK); - break; - case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: - error = blkdev_issue_discard(bdev, start >> 9, len >> 9, - GFP_KERNEL, 0); - break; - default: - return -EOPNOTSUPP; - } - if (error) - return error; - - /* - * Invalidate again; if someone wandered in and dirtied a page, - * the caller will be given -EBUSY. The third argument is - * inclusive, so the rounding here is safe. - */ - return invalidate_inode_pages2_range(mapping, - start >> PAGE_SHIFT, - end >> PAGE_SHIFT); -} - -const struct file_operations def_blk_fops = { - .open = blkdev_open, - .release = blkdev_close, - .llseek = block_llseek, - .read_iter = blkdev_read_iter, - .write_iter = blkdev_write_iter, - .iopoll = blkdev_iopoll, - .mmap = generic_file_mmap, - .fsync = blkdev_fsync, - .unlocked_ioctl = block_ioctl, -#ifdef CONFIG_COMPAT - .compat_ioctl = compat_blkdev_ioctl, -#endif - .splice_read = generic_file_splice_read, - .splice_write = iter_file_splice_write, - .fallocate = blkdev_fallocate, -}; - -int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) -{ - int res; - mm_segment_t old_fs = get_fs(); - set_fs(KERNEL_DS); - res = blkdev_ioctl(bdev, 0, cmd, arg); - set_fs(old_fs); - return res; -} - -EXPORT_SYMBOL(ioctl_by_bdev); - -/** - * lookup_bdev - lookup a struct block_device by name - * @pathname: special file representing the block device - * - * Get a reference to the blockdevice at @pathname in the current - * namespace if possible and return it. Return ERR_PTR(error) - * otherwise. - */ -struct block_device *lookup_bdev(const char *pathname) -{ - struct block_device *bdev; - struct inode *inode; - struct path path; - int error; - - if (!pathname || !*pathname) - return ERR_PTR(-EINVAL); - - error = kern_path(pathname, LOOKUP_FOLLOW, &path); - if (error) - return ERR_PTR(error); - - inode = d_backing_inode(path.dentry); - error = -ENOTBLK; - if (!S_ISBLK(inode->i_mode)) - goto fail; - error = -EACCES; - if (!may_open_dev(&path)) - goto fail; - error = -ENOMEM; - bdev = bd_acquire(inode); - if (!bdev) - goto fail; -out: - path_put(&path); - return bdev; -fail: - bdev = ERR_PTR(error); - goto out; -} -EXPORT_SYMBOL(lookup_bdev); - -int __invalidate_device(struct block_device *bdev, bool kill_dirty) -{ - struct super_block *sb = get_super(bdev); - int res = 0; - - if (sb) { - /* - * no need to lock the super, get_super holds the - * read mutex so the filesystem cannot go away - * under us (->put_super runs with the write lock - * hold). - */ - shrink_dcache_sb(sb); - res = invalidate_inodes(sb, kill_dirty); - drop_super(sb); - } - invalidate_bdev(bdev); - return res; -} -EXPORT_SYMBOL(__invalidate_device); - -void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) -{ - struct inode *inode, *old_inode = NULL; - - spin_lock(&blockdev_superblock->s_inode_list_lock); - list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { - struct address_space *mapping = inode->i_mapping; - struct block_device *bdev; - - spin_lock(&inode->i_lock); - if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || - mapping->nrpages == 0) { - spin_unlock(&inode->i_lock); - continue; - } - __iget(inode); - spin_unlock(&inode->i_lock); - spin_unlock(&blockdev_superblock->s_inode_list_lock); - /* - * We hold a reference to 'inode' so it couldn't have been - * removed from s_inodes list while we dropped the - * s_inode_list_lock We cannot iput the inode now as we can - * be holding the last reference and we cannot iput it under - * s_inode_list_lock. So we keep the reference and iput it - * later. - */ - iput(old_inode); - old_inode = inode; - bdev = I_BDEV(inode); - - mutex_lock(&bdev->bd_mutex); - if (bdev->bd_openers) - func(bdev, arg); - mutex_unlock(&bdev->bd_mutex); - - spin_lock(&blockdev_superblock->s_inode_list_lock); - } - spin_unlock(&blockdev_superblock->s_inode_list_lock); - iput(old_inode); -} |