| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
| * Copyright (C) 2016 - 2020 Christoph Hellwig |
| */ |
| |
| #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/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/part_stat.h> |
| #include <linux/uaccess.h> |
| #include <linux/suspend.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.. */ |
| static 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); |
| } |
| |
| /* 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); |
| |
| /* |
| * Drop all buffers & page cache for given bdev range. This function bails |
| * with error if bdev has other exclusive owner (such as filesystem). |
| */ |
| int truncate_bdev_range(struct block_device *bdev, fmode_t mode, |
| loff_t lstart, loff_t lend) |
| { |
| /* |
| * If we don't hold exclusive handle for the device, upgrade to it |
| * while we discard the buffer cache to avoid discarding buffers |
| * under live filesystem. |
| */ |
| if (!(mode & FMODE_EXCL)) { |
| int err = bd_prepare_to_claim(bdev, truncate_bdev_range); |
| if (err) |
| goto invalidate; |
| } |
| |
| truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); |
| if (!(mode & FMODE_EXCL)) |
| bd_abort_claiming(bdev, truncate_bdev_range); |
| return 0; |
| |
| invalidate: |
| /* |
| * Someone else has handle exclusively open. Try invalidating instead. |
| * The 'end' argument is inclusive so the rounding is safe. |
| */ |
| return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, |
| lstart >> PAGE_SHIFT, |
| lend >> PAGE_SHIFT); |
| } |
| |
| static void set_init_blocksize(struct block_device *bdev) |
| { |
| unsigned int 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_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_inode->i_blkbits != blksize_bits(size)) { |
| sync_blockdev(bdev); |
| 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, |
| unsigned 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)) |
| blk_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, |
| unsigned 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 = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); |
| 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)) |
| blk_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) |
| { |
| unsigned int nr_pages; |
| |
| if (!iov_iter_count(iter)) |
| return 0; |
| |
| nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); |
| if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_VECS) |
| return __blkdev_direct_IO_simple(iocb, iter, nr_pages); |
| |
| return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_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. |
| */ |
| int 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) |
| goto done; |
| |
| sb = get_active_super(bdev); |
| if (!sb) |
| goto sync; |
| if (sb->s_op->freeze_super) |
| error = sb->s_op->freeze_super(sb); |
| else |
| error = freeze_super(sb); |
| deactivate_super(sb); |
| |
| if (error) { |
| bdev->bd_fsfreeze_count--; |
| goto done; |
| } |
| bdev->bd_fsfreeze_sb = sb; |
| |
| sync: |
| sync_blockdev(bdev); |
| done: |
| mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL(freeze_bdev); |
| |
| /** |
| * thaw_bdev -- unlock filesystem |
| * @bdev: blockdevice to unlock |
| * |
| * 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; |
| |
| sb = bdev->bd_fsfreeze_sb; |
| 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++; |
| else |
| bdev->bd_fsfreeze_sb = NULL; |
| 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 void blkdev_readahead(struct readahead_control *rac) |
| { |
| mpage_readahead(rac, 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); |
| 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_disk->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_disk->queue); |
| return result; |
| } |
| |
| /** |
| * 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_disk->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_disk->queue); |
| return result; |
| } |
| |
| /* |
| * 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; |
| memset(&ei->bdev, 0, sizeof(ei->bdev)); |
| ei->bdev.bd_bdi = &noop_backing_dev_info; |
| return &ei->vfs_inode; |
| } |
| |
| static void bdev_free_inode(struct inode *inode) |
| { |
| struct block_device *bdev = I_BDEV(inode); |
| |
| free_percpu(bdev->bd_stats); |
| kfree(bdev->bd_meta_info); |
| |
| kmem_cache_free(bdev_cachep, BDEV_I(inode)); |
| } |
| |
| static void init_once(void *data) |
| { |
| struct bdev_inode *ei = data; |
| |
| inode_init_once(&ei->vfs_inode); |
| } |
| |
| 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); |
| /* 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 */ |
| } |
| |
| struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) |
| { |
| struct block_device *bdev; |
| struct inode *inode; |
| |
| inode = new_inode(blockdev_superblock); |
| if (!inode) |
| return NULL; |
| inode->i_mode = S_IFBLK; |
| inode->i_rdev = 0; |
| inode->i_data.a_ops = &def_blk_aops; |
| mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
| |
| bdev = I_BDEV(inode); |
| mutex_init(&bdev->bd_mutex); |
| mutex_init(&bdev->bd_fsfreeze_mutex); |
| spin_lock_init(&bdev->bd_size_lock); |
| bdev->bd_disk = disk; |
| bdev->bd_partno = partno; |
| bdev->bd_inode = inode; |
| #ifdef CONFIG_SYSFS |
| INIT_LIST_HEAD(&bdev->bd_holder_disks); |
| #endif |
| bdev->bd_stats = alloc_percpu(struct disk_stats); |
| if (!bdev->bd_stats) { |
| iput(inode); |
| return NULL; |
| } |
| return bdev; |
| } |
| |
| void bdev_add(struct block_device *bdev, dev_t dev) |
| { |
| bdev->bd_dev = dev; |
| bdev->bd_inode->i_rdev = dev; |
| bdev->bd_inode->i_ino = dev; |
| insert_inode_hash(bdev->bd_inode); |
| } |
| |
| static struct block_device *bdget(dev_t dev) |
| { |
| struct inode *inode; |
| |
| inode = ilookup(blockdev_superblock, dev); |
| if (!inode) |
| return NULL; |
| return &BDEV_I(inode)->bdev; |
| } |
| |
| /** |
| * bdgrab -- Grab a reference to an already referenced block device |
| * @bdev: Block device to grab a reference to. |
| * |
| * Returns the block_device with an additional reference when successful, |
| * or NULL if the inode is already beeing freed. |
| */ |
| struct block_device *bdgrab(struct block_device *bdev) |
| { |
| if (!igrab(bdev->bd_inode)) |
| return NULL; |
| return bdev; |
| } |
| EXPORT_SYMBOL(bdgrab); |
| |
| long nr_blockdev_pages(void) |
| { |
| struct inode *inode; |
| long ret = 0; |
| |
| spin_lock(&blockdev_superblock->s_inode_list_lock); |
| list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) |
| ret += inode->i_mapping->nrpages; |
| spin_unlock(&blockdev_superblock->s_inode_list_lock); |
| |
| return ret; |
| } |
| |
| void bdput(struct block_device *bdev) |
| { |
| iput(bdev->bd_inode); |
| } |
| EXPORT_SYMBOL(bdput); |
| |
| /** |
| * 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 - claim a block device |
| * @bdev: block device of interest |
| * @holder: holder trying to claim @bdev |
| * |
| * Claim @bdev. This function fails if @bdev is already claimed by another |
| * holder and waits if another claiming is in progress. return, the caller |
| * has ownership of bd_claiming and bd_holder[s]. |
| * |
| * RETURNS: |
| * 0 if @bdev can be claimed, -EBUSY otherwise. |
| */ |
| int bd_prepare_to_claim(struct block_device *bdev, void *holder) |
| { |
| struct block_device *whole = bdev_whole(bdev); |
| |
| if (WARN_ON_ONCE(!holder)) |
| return -EINVAL; |
| retry: |
| spin_lock(&bdev_lock); |
| /* if someone else claimed, fail */ |
| if (!bd_may_claim(bdev, whole, holder)) { |
| spin_unlock(&bdev_lock); |
| 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); |
| goto retry; |
| } |
| |
| /* yay, all mine */ |
| whole->bd_claiming = holder; |
| spin_unlock(&bdev_lock); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ |
| |
| 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 |
| * @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. |
| */ |
| static void bd_finish_claiming(struct block_device *bdev, void *holder) |
| { |
| struct block_device *whole = bdev_whole(bdev); |
| |
| 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); |
| } |
| |
| /** |
| * bd_abort_claiming - abort claiming of a block device |
| * @bdev: block device of interest |
| * @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, void *holder) |
| { |
| spin_lock(&bdev_lock); |
| bd_clear_claiming(bdev_whole(bdev), 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_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, bdev_kobj(bdev)); |
| if (ret) |
| goto out_free; |
| |
| ret = add_symlink(bdev->bd_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_holder_dir); |
| |
| list_add(&holder->list, &bdev->bd_holder_disks); |
| goto out_unlock; |
| |
| out_del: |
| del_symlink(disk->slave_dir, bdev_kobj(bdev)); |
| 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, bdev_kobj(bdev)); |
| del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj); |
| kobject_put(bdev->bd_holder_dir); |
| list_del_init(&holder->list); |
| kfree(holder); |
| } |
| |
| mutex_unlock(&bdev->bd_mutex); |
| } |
| EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
| #endif |
| |
| 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(bdev); |
| if (ret) |
| return ret; |
| |
| clear_bit(GD_NEED_PART_SCAN, &disk->state); |
| |
| /* |
| * Historically we only set the capacity to zero for devices that |
| * support partitions (independ of actually having partitions created). |
| * Doing that is rather inconsistent, but changing it broke legacy |
| * udisks polling for legacy ide-cdrom devices. Use the crude check |
| * below to get the sane behavior for most device while not breaking |
| * userspace for this particular setup. |
| */ |
| if (invalidate) { |
| if (disk_part_scan_enabled(disk) || |
| !(disk->flags & GENHD_FL_REMOVABLE)) |
| set_capacity(disk, 0); |
| } else { |
| if (disk->fops->revalidate_disk) |
| disk->fops->revalidate_disk(disk); |
| } |
| |
| 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 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) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| int ret = 0; |
| |
| if (!bdev->bd_openers) { |
| if (!bdev_is_partition(bdev)) { |
| ret = 0; |
| if (disk->fops->open) |
| ret = disk->fops->open(bdev, mode); |
| |
| if (!ret) |
| 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 (test_bit(GD_NEED_PART_SCAN, &disk->state) && |
| (!ret || ret == -ENOMEDIUM)) |
| bdev_disk_changed(bdev, ret == -ENOMEDIUM); |
| |
| if (ret) |
| return ret; |
| } else { |
| struct block_device *whole = bdgrab(disk->part0); |
| |
| mutex_lock_nested(&whole->bd_mutex, 1); |
| ret = __blkdev_get(whole, mode); |
| if (ret) { |
| mutex_unlock(&whole->bd_mutex); |
| bdput(whole); |
| return ret; |
| } |
| whole->bd_part_count++; |
| mutex_unlock(&whole->bd_mutex); |
| |
| if (!(disk->flags & GENHD_FL_UP) || |
| !bdev_nr_sectors(bdev)) { |
| __blkdev_put(whole, mode, 1); |
| bdput(whole); |
| return -ENXIO; |
| } |
| 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_is_partition(bdev)) { |
| if (bdev->bd_disk->fops->open) |
| ret = bdev->bd_disk->fops->open(bdev, mode); |
| /* the same as first opener case, read comment there */ |
| if (test_bit(GD_NEED_PART_SCAN, &disk->state) && |
| (!ret || ret == -ENOMEDIUM)) |
| bdev_disk_changed(bdev, ret == -ENOMEDIUM); |
| if (ret) |
| return ret; |
| } |
| } |
| bdev->bd_openers++; |
| return 0; |
| } |
| |
| struct block_device *blkdev_get_no_open(dev_t dev) |
| { |
| struct block_device *bdev; |
| struct gendisk *disk; |
| |
| down_read(&bdev_lookup_sem); |
| bdev = bdget(dev); |
| if (!bdev) { |
| up_read(&bdev_lookup_sem); |
| blk_request_module(dev); |
| down_read(&bdev_lookup_sem); |
| |
| bdev = bdget(dev); |
| if (!bdev) |
| goto unlock; |
| } |
| |
| disk = bdev->bd_disk; |
| if (!kobject_get_unless_zero(&disk_to_dev(disk)->kobj)) |
| goto bdput; |
| if ((disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) |
| goto put_disk; |
| if (!try_module_get(bdev->bd_disk->fops->owner)) |
| goto put_disk; |
| up_read(&bdev_lookup_sem); |
| return bdev; |
| put_disk: |
| put_disk(disk); |
| bdput: |
| bdput(bdev); |
| unlock: |
| up_read(&bdev_lookup_sem); |
| return NULL; |
| } |
| |
| void blkdev_put_no_open(struct block_device *bdev) |
| { |
| module_put(bdev->bd_disk->fops->owner); |
| put_disk(bdev->bd_disk); |
| bdput(bdev); |
| } |
| |
| /** |
| * 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 block device described by device number @dev. If @mode includes |
| * %FMODE_EXCL, the block device is opened with exclusive access. Specifying |
| * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for |
| * the same @holder. |
| * |
| * Use this interface 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. Everything else should use blkdev_get_by_path(). |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * Reference to the block_device on success, ERR_PTR(-errno) on failure. |
| */ |
| struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) |
| { |
| bool unblock_events = true; |
| struct block_device *bdev; |
| struct gendisk *disk; |
| int ret; |
| |
| ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, |
| MAJOR(dev), MINOR(dev), |
| ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) | |
| ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0)); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| /* |
| * If we lost a race with 'disk' being deleted, try again. See md.c. |
| */ |
| retry: |
| bdev = blkdev_get_no_open(dev); |
| if (!bdev) |
| return ERR_PTR(-ENXIO); |
| disk = bdev->bd_disk; |
| |
| if (mode & FMODE_EXCL) { |
| ret = bd_prepare_to_claim(bdev, holder); |
| if (ret) |
| goto put_blkdev; |
| } |
| |
| disk_block_events(disk); |
| |
| mutex_lock(&bdev->bd_mutex); |
| ret =__blkdev_get(bdev, mode); |
| if (ret) |
| goto abort_claiming; |
| if (mode & FMODE_EXCL) { |
| bd_finish_claiming(bdev, 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 ((mode & FMODE_WRITE) && !bdev->bd_write_holder && |
| (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { |
| bdev->bd_write_holder = true; |
| unblock_events = false; |
| } |
| } |
| mutex_unlock(&bdev->bd_mutex); |
| |
| if (unblock_events) |
| disk_unblock_events(disk); |
| return bdev; |
| |
| abort_claiming: |
| if (mode & FMODE_EXCL) |
| bd_abort_claiming(bdev, holder); |
| mutex_unlock(&bdev->bd_mutex); |
| disk_unblock_events(disk); |
| put_blkdev: |
| blkdev_put_no_open(bdev); |
| if (ret == -ERESTARTSYS) |
| goto retry; |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL(blkdev_get_by_dev); |
| |
| /** |
| * 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 block device described by the device file at @path. If @mode |
| * includes %FMODE_EXCL, the block device is opened with exclusive access. |
| * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may |
| * nest for the same @holder. |
| * |
| * CONTEXT: |
| * Might sleep. |
| * |
| * RETURNS: |
| * Reference to the 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; |
| dev_t dev; |
| int error; |
| |
| error = lookup_bdev(path, &dev); |
| if (error) |
| return ERR_PTR(error); |
| |
| bdev = blkdev_get_by_dev(dev, mode, holder); |
| if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
| blkdev_put(bdev, mode); |
| return ERR_PTR(-EACCES); |
| } |
| |
| return bdev; |
| } |
| EXPORT_SYMBOL(blkdev_get_by_path); |
| |
| 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 | FMODE_BUF_RASYNC; |
| |
| 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 = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); |
| if (IS_ERR(bdev)) |
| return PTR_ERR(bdev); |
| filp->f_mapping = bdev->bd_inode->i_mapping; |
| filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); |
| return 0; |
| } |
| |
| 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; |
| |
| /* |
| * Sync early if it looks like we're the last one. If someone else |
| * opens the block device between now and the decrement of bd_openers |
| * then we did a sync that we didn't need to, but that's not the end |
| * of the world and we want to avoid long (could be several minute) |
| * syncs while holding the mutex. |
| */ |
| if (bdev->bd_openers == 1) |
| sync_blockdev(bdev); |
| |
| 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_is_partition(bdev)) |
| victim = bdev_whole(bdev); |
| } |
| |
| if (!bdev_is_partition(bdev) && disk->fops->release) |
| disk->fops->release(disk, mode); |
| mutex_unlock(&bdev->bd_mutex); |
| if (victim) { |
| __blkdev_put(victim, mode, 1); |
| bdput(victim); |
| } |
| } |
| |
| void blkdev_put(struct block_device *bdev, fmode_t mode) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| |
| mutex_lock(&bdev->bd_mutex); |
| |
| if (mode & FMODE_EXCL) { |
| struct block_device *whole = bdev_whole(bdev); |
| 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(--whole->bd_holders < 0); |
| |
| if ((bdev_free = !bdev->bd_holders)) |
| bdev->bd_holder = NULL; |
| if (!whole->bd_holders) |
| whole->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(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(disk, DISK_EVENT_MEDIA_CHANGE); |
| mutex_unlock(&bdev->bd_mutex); |
| |
| __blkdev_put(bdev, mode, 0); |
| blkdev_put_no_open(bdev); |
| } |
| 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) && !is_hibernate_resume_dev(bd_inode->i_rdev)) |
| 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, |
| .readahead = blkdev_readahead, |
| .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)); |
| 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. */ |
| error = truncate_bdev_range(bdev, file->f_mode, start, end); |
| if (error) |
| return error; |
| |
| 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 the page cache again; if someone wandered in and dirtied |
| * a page, we just discard it - userspace has no way of knowing whether |
| * the write happened before or after discard completing... |
| */ |
| return truncate_bdev_range(bdev, file->f_mode, start, end); |
| } |
| |
| 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, |
| }; |
| |
| /** |
| * lookup_bdev - lookup a struct block_device by name |
| * @pathname: special file representing the block device |
| * @dev: return value of the block device's dev_t |
| * |
| * Get a reference to the blockdevice at @pathname in the current |
| * namespace if possible and return it. Return ERR_PTR(error) |
| * otherwise. |
| */ |
| int lookup_bdev(const char *pathname, dev_t *dev) |
| { |
| struct inode *inode; |
| struct path path; |
| int error; |
| |
| if (!pathname || !*pathname) |
| return -EINVAL; |
| |
| error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
| if (error) |
| return error; |
| |
| inode = d_backing_inode(path.dentry); |
| error = -ENOTBLK; |
| if (!S_ISBLK(inode->i_mode)) |
| goto out_path_put; |
| error = -EACCES; |
| if (!may_open_dev(&path)) |
| goto out_path_put; |
| |
| *dev = inode->i_rdev; |
| error = 0; |
| out_path_put: |
| path_put(&path); |
| return error; |
| } |
| 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); |
| } |