--- /dev/null
+// 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/blkdev.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/uio.h>
+#include <linux/namei.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/falloc.h>
+#include <linux/suspend.h>
+#include "blk.h"
+
+static struct inode *bdev_file_inode(struct file *file)
+{
+ return file->f_mapping->host;
+}
+
+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 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_NOWAIT)
+ bio.bi_opf |= REQ_NOWAIT;
+ 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_kiocb(iocb, 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);
+ }
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ bio->bi_opf |= REQ_NOWAIT;
+
+ 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 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;
+}
+
+static int blkdev_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ return generic_writepages(mapping, wbc);
+}
+
+const struct address_space_operations def_blk_aops = {
+ .set_page_dirty = __set_page_dirty_buffers,
+ .readpage = blkdev_readpage,
+ .readahead = blkdev_readahead,
+ .writepage = blkdev_writepage,
+ .write_begin = blkdev_write_begin,
+ .write_end = blkdev_write_end,
+ .writepages = blkdev_writepages,
+ .direct_IO = blkdev_direct_IO,
+ .migratepage = buffer_migrate_page_norefs,
+ .is_dirty_writeback = buffer_check_dirty_writeback,
+};
+
+/*
+ * 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 blkdev_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;
+}
+
+static 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;
+}
+
+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 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.
+ */
+static 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;
+ size_t shorted = 0;
+ 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;
+
+ size -= iocb->ki_pos;
+ if (iov_iter_count(from) > size) {
+ shorted = iov_iter_count(from) - size;
+ iov_iter_truncate(from, size);
+ }
+
+ blk_start_plug(&plug);
+ ret = __generic_file_write_iter(iocb, from);
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+ iov_iter_reexpand(from, iov_iter_count(from) + shorted);
+ blk_finish_plug(&plug);
+ return ret;
+}
+
+static 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;
+ size_t shorted = 0;
+ ssize_t ret;
+
+ if (pos >= size)
+ return 0;
+
+ size -= pos;
+ if (iov_iter_count(to) > size) {
+ shorted = iov_iter_count(to) - size;
+ iov_iter_truncate(to, size);
+ }
+
+ ret = generic_file_read_iter(iocb, to);
+ iov_iter_reexpand(to, iov_iter_count(to) + shorted);
+ return ret;
+}
+
+#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 = blkdev_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,
+};
+
+static __init int blkdev_init(void)
+{
+ return bioset_init(&blkdev_dio_pool, 4,
+ offsetof(struct blkdev_dio, bio),
+ BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
+}
+module_init(blkdev_init);
git.samba.org / sfrench / cifs-2.6.git / blobdiff