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-rw-r--r--block/fops.c850
1 files changed, 850 insertions, 0 deletions
diff --git a/block/fops.c b/block/fops.c
new file mode 100644
index 0000000000..73e4274254
--- /dev/null
+++ b/block/fops.c
@@ -0,0 +1,850 @@
+// 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 <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/module.h>
+#include "blk.h"
+
+static inline struct inode *bdev_file_inode(struct file *file)
+{
+ return file->f_mapping->host;
+}
+
+static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
+{
+ blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
+
+ /* avoid the need for a I/O completion work item */
+ if (iocb_is_dsync(iocb))
+ opf |= REQ_FUA;
+ return opf;
+}
+
+static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos,
+ struct iov_iter *iter)
+{
+ return pos & (bdev_logical_block_size(bdev) - 1) ||
+ !bdev_iter_is_aligned(bdev, iter);
+}
+
+#define DIO_INLINE_BIO_VECS 4
+
+static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
+ struct iov_iter *iter, unsigned int nr_pages)
+{
+ struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+ 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;
+
+ if (blkdev_dio_unaligned(bdev, pos, iter))
+ 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;
+ }
+
+ if (iov_iter_rw(iter) == READ) {
+ bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
+ if (user_backed_iter(iter))
+ should_dirty = true;
+ } else {
+ bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
+ }
+ bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
+ 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) == WRITE)
+ task_io_account_write(ret);
+
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ bio.bi_opf |= REQ_NOWAIT;
+
+ submit_bio_wait(&bio);
+
+ 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;
+}
+
+enum {
+ DIO_SHOULD_DIRTY = 1,
+ DIO_IS_SYNC = 2,
+};
+
+struct blkdev_dio {
+ union {
+ struct kiocb *iocb;
+ struct task_struct *waiter;
+ };
+ size_t size;
+ atomic_t ref;
+ unsigned int flags;
+ struct bio bio ____cacheline_aligned_in_smp;
+};
+
+static struct bio_set blkdev_dio_pool;
+
+static void blkdev_bio_end_io(struct bio *bio)
+{
+ struct blkdev_dio *dio = bio->bi_private;
+ bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
+
+ if (bio->bi_status && !dio->bio.bi_status)
+ dio->bio.bi_status = bio->bi_status;
+
+ if (atomic_dec_and_test(&dio->ref)) {
+ if (!(dio->flags & DIO_IS_SYNC)) {
+ struct kiocb *iocb = dio->iocb;
+ ssize_t ret;
+
+ WRITE_ONCE(iocb->private, NULL);
+
+ 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);
+ 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 block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+ struct blk_plug plug;
+ struct blkdev_dio *dio;
+ struct bio *bio;
+ bool is_read = (iov_iter_rw(iter) == READ), is_sync;
+ blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
+ loff_t pos = iocb->ki_pos;
+ int ret = 0;
+
+ if (blkdev_dio_unaligned(bdev, pos, iter))
+ return -EINVAL;
+
+ if (iocb->ki_flags & IOCB_ALLOC_CACHE)
+ opf |= REQ_ALLOC_CACHE;
+ bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
+ &blkdev_dio_pool);
+ dio = container_of(bio, struct blkdev_dio, bio);
+ atomic_set(&dio->ref, 1);
+ /*
+ * Grab an extra reference to ensure the dio structure which is embedded
+ * into the first bio stays around.
+ */
+ bio_get(bio);
+
+ is_sync = is_sync_kiocb(iocb);
+ if (is_sync) {
+ dio->flags = DIO_IS_SYNC;
+ dio->waiter = current;
+ } else {
+ dio->flags = 0;
+ dio->iocb = iocb;
+ }
+
+ dio->size = 0;
+ if (is_read && user_backed_iter(iter))
+ dio->flags |= DIO_SHOULD_DIRTY;
+
+ blk_start_plug(&plug);
+
+ for (;;) {
+ bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
+ 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 (iocb->ki_flags & IOCB_NOWAIT) {
+ /*
+ * This is nonblocking IO, and we need to allocate
+ * another bio if we have data left to map. As we
+ * cannot guarantee that one of the sub bios will not
+ * fail getting issued FOR NOWAIT and as error results
+ * are coalesced across all of them, be safe and ask for
+ * a retry of this from blocking context.
+ */
+ if (unlikely(iov_iter_count(iter))) {
+ bio_release_pages(bio, false);
+ bio_clear_flag(bio, BIO_REFFED);
+ bio_put(bio);
+ blk_finish_plug(&plug);
+ return -EAGAIN;
+ }
+ bio->bi_opf |= REQ_NOWAIT;
+ }
+
+ if (is_read) {
+ if (dio->flags & DIO_SHOULD_DIRTY)
+ bio_set_pages_dirty(bio);
+ } else {
+ 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) {
+ submit_bio(bio);
+ break;
+ }
+ atomic_inc(&dio->ref);
+ submit_bio(bio);
+ bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
+ }
+
+ blk_finish_plug(&plug);
+
+ if (!is_sync)
+ return -EIOCBQUEUED;
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!READ_ONCE(dio->waiter))
+ break;
+ 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 void blkdev_bio_end_io_async(struct bio *bio)
+{
+ struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
+ struct kiocb *iocb = dio->iocb;
+ ssize_t ret;
+
+ WRITE_ONCE(iocb->private, NULL);
+
+ if (likely(!bio->bi_status)) {
+ ret = dio->size;
+ iocb->ki_pos += ret;
+ } else {
+ ret = blk_status_to_errno(bio->bi_status);
+ }
+
+ iocb->ki_complete(iocb, ret);
+
+ if (dio->flags & DIO_SHOULD_DIRTY) {
+ bio_check_pages_dirty(bio);
+ } else {
+ bio_release_pages(bio, false);
+ bio_put(bio);
+ }
+}
+
+static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
+ struct iov_iter *iter,
+ unsigned int nr_pages)
+{
+ struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+ bool is_read = iov_iter_rw(iter) == READ;
+ blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
+ struct blkdev_dio *dio;
+ struct bio *bio;
+ loff_t pos = iocb->ki_pos;
+ int ret = 0;
+
+ if (blkdev_dio_unaligned(bdev, pos, iter))
+ return -EINVAL;
+
+ if (iocb->ki_flags & IOCB_ALLOC_CACHE)
+ opf |= REQ_ALLOC_CACHE;
+ bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
+ &blkdev_dio_pool);
+ dio = container_of(bio, struct blkdev_dio, bio);
+ dio->flags = 0;
+ dio->iocb = iocb;
+ bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
+ bio->bi_end_io = blkdev_bio_end_io_async;
+ bio->bi_ioprio = iocb->ki_ioprio;
+
+ if (iov_iter_is_bvec(iter)) {
+ /*
+ * Users don't rely on the iterator being in any particular
+ * state for async I/O returning -EIOCBQUEUED, hence we can
+ * avoid expensive iov_iter_advance(). Bypass
+ * bio_iov_iter_get_pages() and set the bvec directly.
+ */
+ bio_iov_bvec_set(bio, iter);
+ } else {
+ ret = bio_iov_iter_get_pages(bio, iter);
+ if (unlikely(ret)) {
+ bio_put(bio);
+ return ret;
+ }
+ }
+ dio->size = bio->bi_iter.bi_size;
+
+ if (is_read) {
+ if (user_backed_iter(iter)) {
+ dio->flags |= DIO_SHOULD_DIRTY;
+ bio_set_pages_dirty(bio);
+ }
+ } else {
+ task_io_account_write(bio->bi_iter.bi_size);
+ }
+
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ bio->bi_opf |= REQ_NOWAIT;
+
+ if (iocb->ki_flags & IOCB_HIPRI) {
+ bio->bi_opf |= REQ_POLLED;
+ submit_bio(bio);
+ WRITE_ONCE(iocb->private, bio);
+ } else {
+ submit_bio(bio);
+ }
+ return -EIOCBQUEUED;
+}
+
+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 (likely(nr_pages <= BIO_MAX_VECS)) {
+ if (is_sync_kiocb(iocb))
+ return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
+ return __blkdev_direct_IO_async(iocb, iter, nr_pages);
+ }
+ return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
+}
+
+static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+ unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
+{
+ struct block_device *bdev = I_BDEV(inode);
+ loff_t isize = i_size_read(inode);
+
+ iomap->bdev = bdev;
+ iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
+ if (iomap->offset >= isize)
+ return -EIO;
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = iomap->offset;
+ iomap->length = isize - iomap->offset;
+ iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
+ return 0;
+}
+
+static const struct iomap_ops blkdev_iomap_ops = {
+ .iomap_begin = blkdev_iomap_begin,
+};
+
+#ifdef CONFIG_BUFFER_HEAD
+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 int blkdev_writepage(struct page *page, struct writeback_control *wbc)
+{
+ return block_write_full_page(page, blkdev_get_block, wbc);
+}
+
+static int blkdev_read_folio(struct file *file, struct folio *folio)
+{
+ return block_read_full_folio(folio, 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, struct page **pagep, void **fsdata)
+{
+ return block_write_begin(mapping, pos, len, 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;
+}
+
+const struct address_space_operations def_blk_aops = {
+ .dirty_folio = block_dirty_folio,
+ .invalidate_folio = block_invalidate_folio,
+ .read_folio = blkdev_read_folio,
+ .readahead = blkdev_readahead,
+ .writepage = blkdev_writepage,
+ .write_begin = blkdev_write_begin,
+ .write_end = blkdev_write_end,
+ .migrate_folio = buffer_migrate_folio_norefs,
+ .is_dirty_writeback = buffer_check_dirty_writeback,
+};
+#else /* CONFIG_BUFFER_HEAD */
+static int blkdev_read_folio(struct file *file, struct folio *folio)
+{
+ return iomap_read_folio(folio, &blkdev_iomap_ops);
+}
+
+static void blkdev_readahead(struct readahead_control *rac)
+{
+ iomap_readahead(rac, &blkdev_iomap_ops);
+}
+
+static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,
+ struct inode *inode, loff_t offset)
+{
+ loff_t isize = i_size_read(inode);
+
+ if (WARN_ON_ONCE(offset >= isize))
+ return -EIO;
+ if (offset >= wpc->iomap.offset &&
+ offset < wpc->iomap.offset + wpc->iomap.length)
+ return 0;
+ return blkdev_iomap_begin(inode, offset, isize - offset,
+ IOMAP_WRITE, &wpc->iomap, NULL);
+}
+
+static const struct iomap_writeback_ops blkdev_writeback_ops = {
+ .map_blocks = blkdev_map_blocks,
+};
+
+static int blkdev_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct iomap_writepage_ctx wpc = { };
+
+ return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
+}
+
+const struct address_space_operations def_blk_aops = {
+ .dirty_folio = filemap_dirty_folio,
+ .release_folio = iomap_release_folio,
+ .invalidate_folio = iomap_invalidate_folio,
+ .read_folio = blkdev_read_folio,
+ .readahead = blkdev_readahead,
+ .writepages = blkdev_writepages,
+ .is_partially_uptodate = iomap_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+ .migrate_folio = filemap_migrate_folio,
+};
+#endif /* CONFIG_BUFFER_HEAD */
+
+/*
+ * 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 block_device *bdev = I_BDEV(filp->f_mapping->host);
+ 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;
+}
+
+blk_mode_t file_to_blk_mode(struct file *file)
+{
+ blk_mode_t mode = 0;
+
+ if (file->f_mode & FMODE_READ)
+ mode |= BLK_OPEN_READ;
+ if (file->f_mode & FMODE_WRITE)
+ mode |= BLK_OPEN_WRITE;
+ if (file->private_data)
+ mode |= BLK_OPEN_EXCL;
+ if (file->f_flags & O_NDELAY)
+ mode |= BLK_OPEN_NDELAY;
+
+ /*
+ * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
+ * driver has historically allowed ioctls as if the file was opened for
+ * writing, but does not allow and actual reads or writes.
+ */
+ if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
+ mode |= BLK_OPEN_WRITE_IOCTL;
+
+ return mode;
+}
+
+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_BUF_RASYNC | FMODE_CAN_ODIRECT;
+
+ /*
+ * Use the file private data to store the holder for exclusive openes.
+ * file_to_blk_mode relies on it being present to set BLK_OPEN_EXCL.
+ */
+ if (filp->f_flags & O_EXCL)
+ filp->private_data = filp;
+
+ bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp),
+ filp->private_data, NULL);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+
+ if (bdev_nowait(bdev))
+ filp->f_mode |= FMODE_NOWAIT;
+
+ filp->f_mapping = bdev->bd_inode->i_mapping;
+ filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
+ return 0;
+}
+
+static int blkdev_release(struct inode *inode, struct file *filp)
+{
+ blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data);
+ return 0;
+}
+
+static ssize_t
+blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ size_t count = iov_iter_count(from);
+ ssize_t written;
+
+ written = kiocb_invalidate_pages(iocb, count);
+ if (written) {
+ if (written == -EBUSY)
+ return 0;
+ return written;
+ }
+
+ written = blkdev_direct_IO(iocb, from);
+ if (written > 0) {
+ kiocb_invalidate_post_direct_write(iocb, count);
+ iocb->ki_pos += written;
+ count -= written;
+ }
+ if (written != -EIOCBQUEUED)
+ iov_iter_revert(from, count - iov_iter_count(from));
+ return written;
+}
+
+static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops);
+}
+
+/*
+ * 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 block_device *bdev = I_BDEV(file->f_mapping->host);
+ struct inode *bd_inode = bdev->bd_inode;
+ loff_t size = bdev_nr_bytes(bdev);
+ size_t shorted = 0;
+ ssize_t ret;
+
+ if (bdev_read_only(bdev))
+ 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);
+ }
+
+ ret = file_update_time(file);
+ if (ret)
+ return ret;
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ ret = blkdev_direct_write(iocb, from);
+ if (ret >= 0 && iov_iter_count(from))
+ ret = direct_write_fallback(iocb, from, ret,
+ blkdev_buffered_write(iocb, from));
+ } else {
+ ret = blkdev_buffered_write(iocb, from);
+ }
+
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+ iov_iter_reexpand(from, iov_iter_count(from) + shorted);
+ return ret;
+}
+
+static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+ loff_t size = bdev_nr_bytes(bdev);
+ loff_t pos = iocb->ki_pos;
+ size_t shorted = 0;
+ ssize_t ret = 0;
+ size_t count;
+
+ if (unlikely(pos + iov_iter_count(to) > size)) {
+ if (pos >= size)
+ return 0;
+ size -= pos;
+ shorted = iov_iter_count(to) - size;
+ iov_iter_truncate(to, size);
+ }
+
+ count = iov_iter_count(to);
+ if (!count)
+ goto reexpand; /* skip atime */
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ ret = kiocb_write_and_wait(iocb, count);
+ if (ret < 0)
+ goto reexpand;
+ file_accessed(iocb->ki_filp);
+
+ ret = blkdev_direct_IO(iocb, to);
+ if (ret >= 0) {
+ iocb->ki_pos += ret;
+ count -= ret;
+ }
+ iov_iter_revert(to, count - iov_iter_count(to));
+ if (ret < 0 || !count)
+ goto reexpand;
+ }
+
+ ret = filemap_read(iocb, to, ret);
+
+reexpand:
+ if (unlikely(shorted))
+ 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 inode *inode = bdev_file_inode(file);
+ struct block_device *bdev = I_BDEV(inode);
+ 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 = bdev_nr_bytes(bdev);
+ 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;
+
+ filemap_invalidate_lock(inode->i_mapping);
+
+ /*
+ * Invalidate the page cache, including dirty pages, for valid
+ * de-allocate mode calls to fallocate().
+ */
+ switch (mode) {
+ case FALLOC_FL_ZERO_RANGE:
+ case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
+ error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
+ if (error)
+ goto fail;
+
+ error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
+ len >> SECTOR_SHIFT, GFP_KERNEL,
+ BLKDEV_ZERO_NOUNMAP);
+ break;
+ case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
+ error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
+ if (error)
+ goto fail;
+
+ error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
+ len >> SECTOR_SHIFT, GFP_KERNEL,
+ BLKDEV_ZERO_NOFALLBACK);
+ break;
+ case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
+ error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
+ if (error)
+ goto fail;
+
+ error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
+ len >> SECTOR_SHIFT, GFP_KERNEL);
+ break;
+ default:
+ error = -EOPNOTSUPP;
+ }
+
+ fail:
+ filemap_invalidate_unlock(inode->i_mapping);
+ return error;
+}
+
+static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct inode *bd_inode = bdev_file_inode(file);
+
+ if (bdev_read_only(I_BDEV(bd_inode)))
+ return generic_file_readonly_mmap(file, vma);
+
+ return generic_file_mmap(file, vma);
+}
+
+const struct file_operations def_blk_fops = {
+ .open = blkdev_open,
+ .release = blkdev_release,
+ .llseek = blkdev_llseek,
+ .read_iter = blkdev_read_iter,
+ .write_iter = blkdev_write_iter,
+ .iopoll = iocb_bio_iopoll,
+ .mmap = blkdev_mmap,
+ .fsync = blkdev_fsync,
+ .unlocked_ioctl = blkdev_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = compat_blkdev_ioctl,
+#endif
+ .splice_read = filemap_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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 05:16:52 +0000