#include <linux/uio.h>
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
+#include <linux/task_io_accounting_ops.h>
#include <linux/dax.h>
#include "internal.h"
return 0;
}
EXPORT_SYMBOL_GPL(iomap_fiemap);
+
+/*
+ * Private flags for iomap_dio, must not overlap with the public ones in
+ * iomap.h:
+ */
+#define IOMAP_DIO_WRITE (1 << 30)
+#define IOMAP_DIO_DIRTY (1 << 31)
+
+struct iomap_dio {
+ struct kiocb *iocb;
+ iomap_dio_end_io_t *end_io;
+ loff_t i_size;
+ loff_t size;
+ atomic_t ref;
+ unsigned flags;
+ int error;
+
+ union {
+ /* used during submission and for synchronous completion: */
+ struct {
+ struct iov_iter *iter;
+ struct task_struct *waiter;
+ struct request_queue *last_queue;
+ blk_qc_t cookie;
+ } submit;
+
+ /* used for aio completion: */
+ struct {
+ struct work_struct work;
+ } aio;
+ };
+};
+
+static ssize_t iomap_dio_complete(struct iomap_dio *dio)
+{
+ struct kiocb *iocb = dio->iocb;
+ ssize_t ret;
+
+ if (dio->end_io) {
+ ret = dio->end_io(iocb,
+ dio->error ? dio->error : dio->size,
+ dio->flags);
+ } else {
+ ret = dio->error;
+ }
+
+ if (likely(!ret)) {
+ ret = dio->size;
+ /* check for short read */
+ if (iocb->ki_pos + ret > dio->i_size &&
+ !(dio->flags & IOMAP_DIO_WRITE))
+ ret = dio->i_size - iocb->ki_pos;
+ iocb->ki_pos += ret;
+ }
+
+ inode_dio_end(file_inode(iocb->ki_filp));
+ kfree(dio);
+
+ return ret;
+}
+
+static void iomap_dio_complete_work(struct work_struct *work)
+{
+ struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work);
+ struct kiocb *iocb = dio->iocb;
+ bool is_write = (dio->flags & IOMAP_DIO_WRITE);
+ ssize_t ret;
+
+ ret = iomap_dio_complete(dio);
+ if (is_write && ret > 0)
+ ret = generic_write_sync(iocb, ret);
+ iocb->ki_complete(iocb, ret, 0);
+}
+
+/*
+ * Set an error in the dio if none is set yet. We have to use cmpxchg
+ * as the submission context and the completion context(s) can race to
+ * update the error.
+ */
+static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret)
+{
+ cmpxchg(&dio->error, 0, ret);
+}
+
+static void iomap_dio_bio_end_io(struct bio *bio)
+{
+ struct iomap_dio *dio = bio->bi_private;
+ bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
+
+ if (bio->bi_error)
+ iomap_dio_set_error(dio, bio->bi_error);
+
+ if (atomic_dec_and_test(&dio->ref)) {
+ if (is_sync_kiocb(dio->iocb)) {
+ struct task_struct *waiter = dio->submit.waiter;
+
+ WRITE_ONCE(dio->submit.waiter, NULL);
+ wake_up_process(waiter);
+ } else if (dio->flags & IOMAP_DIO_WRITE) {
+ struct inode *inode = file_inode(dio->iocb->ki_filp);
+
+ INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
+ queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
+ } else {
+ iomap_dio_complete_work(&dio->aio.work);
+ }
+ }
+
+ if (should_dirty) {
+ bio_check_pages_dirty(bio);
+ } else {
+ struct bio_vec *bvec;
+ int i;
+
+ bio_for_each_segment_all(bvec, bio, i)
+ put_page(bvec->bv_page);
+ bio_put(bio);
+ }
+}
+
+static blk_qc_t
+iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
+ unsigned len)
+{
+ struct page *page = ZERO_PAGE(0);
+ struct bio *bio;
+
+ bio = bio_alloc(GFP_KERNEL, 1);
+ bio->bi_bdev = iomap->bdev;
+ bio->bi_iter.bi_sector =
+ iomap->blkno + ((pos - iomap->offset) >> 9);
+ bio->bi_private = dio;
+ bio->bi_end_io = iomap_dio_bio_end_io;
+
+ get_page(page);
+ if (bio_add_page(bio, page, len, 0) != len)
+ BUG();
+ bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_ODIRECT);
+
+ atomic_inc(&dio->ref);
+ return submit_bio(bio);
+}
+
+static loff_t
+iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
+ void *data, struct iomap *iomap)
+{
+ struct iomap_dio *dio = data;
+ unsigned blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
+ unsigned fs_block_size = (1 << inode->i_blkbits), pad;
+ unsigned align = iov_iter_alignment(dio->submit.iter);
+ struct iov_iter iter;
+ struct bio *bio;
+ bool need_zeroout = false;
+ int nr_pages, ret;
+
+ if ((pos | length | align) & ((1 << blkbits) - 1))
+ return -EINVAL;
+
+ switch (iomap->type) {
+ case IOMAP_HOLE:
+ if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
+ return -EIO;
+ /*FALLTHRU*/
+ case IOMAP_UNWRITTEN:
+ if (!(dio->flags & IOMAP_DIO_WRITE)) {
+ iov_iter_zero(length, dio->submit.iter);
+ dio->size += length;
+ return length;
+ }
+ dio->flags |= IOMAP_DIO_UNWRITTEN;
+ need_zeroout = true;
+ break;
+ case IOMAP_MAPPED:
+ if (iomap->flags & IOMAP_F_SHARED)
+ dio->flags |= IOMAP_DIO_COW;
+ if (iomap->flags & IOMAP_F_NEW)
+ need_zeroout = true;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EIO;
+ }
+
+ /*
+ * Operate on a partial iter trimmed to the extent we were called for.
+ * We'll update the iter in the dio once we're done with this extent.
+ */
+ iter = *dio->submit.iter;
+ iov_iter_truncate(&iter, length);
+
+ nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
+ if (nr_pages <= 0)
+ return nr_pages;
+
+ if (need_zeroout) {
+ /* zero out from the start of the block to the write offset */
+ pad = pos & (fs_block_size - 1);
+ if (pad)
+ iomap_dio_zero(dio, iomap, pos - pad, pad);
+ }
+
+ do {
+ if (dio->error)
+ return 0;
+
+ bio = bio_alloc(GFP_KERNEL, nr_pages);
+ bio->bi_bdev = iomap->bdev;
+ bio->bi_iter.bi_sector =
+ iomap->blkno + ((pos - iomap->offset) >> 9);
+ bio->bi_private = dio;
+ bio->bi_end_io = iomap_dio_bio_end_io;
+
+ ret = bio_iov_iter_get_pages(bio, &iter);
+ if (unlikely(ret)) {
+ bio_put(bio);
+ return ret;
+ }
+
+ if (dio->flags & IOMAP_DIO_WRITE) {
+ bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_ODIRECT);
+ task_io_account_write(bio->bi_iter.bi_size);
+ } else {
+ bio_set_op_attrs(bio, REQ_OP_READ, 0);
+ if (dio->flags & IOMAP_DIO_DIRTY)
+ bio_set_pages_dirty(bio);
+ }
+
+ dio->size += bio->bi_iter.bi_size;
+ pos += bio->bi_iter.bi_size;
+
+ nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
+
+ atomic_inc(&dio->ref);
+
+ dio->submit.last_queue = bdev_get_queue(iomap->bdev);
+ dio->submit.cookie = submit_bio(bio);
+ } while (nr_pages);
+
+ if (need_zeroout) {
+ /* zero out from the end of the write to the end of the block */
+ pad = pos & (fs_block_size - 1);
+ if (pad)
+ iomap_dio_zero(dio, iomap, pos, fs_block_size - pad);
+ }
+
+ iov_iter_advance(dio->submit.iter, length);
+ return length;
+}
+
+ssize_t
+iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops,
+ iomap_dio_end_io_t end_io)
+{
+ struct address_space *mapping = iocb->ki_filp->f_mapping;
+ struct inode *inode = file_inode(iocb->ki_filp);
+ size_t count = iov_iter_count(iter);
+ loff_t pos = iocb->ki_pos, end = iocb->ki_pos + count - 1, ret = 0;
+ unsigned int flags = IOMAP_DIRECT;
+ struct blk_plug plug;
+ struct iomap_dio *dio;
+
+ lockdep_assert_held(&inode->i_rwsem);
+
+ if (!count)
+ return 0;
+
+ dio = kmalloc(sizeof(*dio), GFP_KERNEL);
+ if (!dio)
+ return -ENOMEM;
+
+ dio->iocb = iocb;
+ atomic_set(&dio->ref, 1);
+ dio->size = 0;
+ dio->i_size = i_size_read(inode);
+ dio->end_io = end_io;
+ dio->error = 0;
+ dio->flags = 0;
+
+ dio->submit.iter = iter;
+ if (is_sync_kiocb(iocb)) {
+ dio->submit.waiter = current;
+ dio->submit.cookie = BLK_QC_T_NONE;
+ dio->submit.last_queue = NULL;
+ }
+
+ if (iov_iter_rw(iter) == READ) {
+ if (pos >= dio->i_size)
+ goto out_free_dio;
+
+ if (iter->type == ITER_IOVEC)
+ dio->flags |= IOMAP_DIO_DIRTY;
+ } else {
+ dio->flags |= IOMAP_DIO_WRITE;
+ flags |= IOMAP_WRITE;
+ }
+
+ if (mapping->nrpages) {
+ ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);
+ if (ret)
+ goto out_free_dio;
+
+ ret = invalidate_inode_pages2_range(mapping,
+ iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
+ WARN_ON_ONCE(ret);
+ ret = 0;
+ }
+
+ inode_dio_begin(inode);
+
+ blk_start_plug(&plug);
+ do {
+ ret = iomap_apply(inode, pos, count, flags, ops, dio,
+ iomap_dio_actor);
+ if (ret <= 0) {
+ /* magic error code to fall back to buffered I/O */
+ if (ret == -ENOTBLK)
+ ret = 0;
+ break;
+ }
+ pos += ret;
+ } while ((count = iov_iter_count(iter)) > 0);
+ blk_finish_plug(&plug);
+
+ if (ret < 0)
+ iomap_dio_set_error(dio, ret);
+
+ if (ret >= 0 && iov_iter_rw(iter) == WRITE && !is_sync_kiocb(iocb) &&
+ !inode->i_sb->s_dio_done_wq) {
+ ret = sb_init_dio_done_wq(inode->i_sb);
+ if (ret < 0)
+ iomap_dio_set_error(dio, ret);
+ }
+
+ if (!atomic_dec_and_test(&dio->ref)) {
+ if (!is_sync_kiocb(iocb))
+ return -EIOCBQUEUED;
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!READ_ONCE(dio->submit.waiter))
+ break;
+
+ if (!(iocb->ki_flags & IOCB_HIPRI) ||
+ !dio->submit.last_queue ||
+ !blk_poll(dio->submit.last_queue,
+ dio->submit.cookie))
+ io_schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+ }
+
+ /*
+ * Try again to invalidate clean pages which might have been cached by
+ * non-direct readahead, or faulted in by get_user_pages() if the source
+ * of the write was an mmap'ed region of the file we're writing. Either
+ * one is a pretty crazy thing to do, so we don't support it 100%. If
+ * this invalidation fails, tough, the write still worked...
+ */
+ if (iov_iter_rw(iter) == WRITE && mapping->nrpages) {
+ ret = invalidate_inode_pages2_range(mapping,
+ iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
+ WARN_ON_ONCE(ret);
+ }
+
+ return iomap_dio_complete(dio);
+
+out_free_dio:
+ kfree(dio);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iomap_dio_rw);
projects / kernel.git / commitdiff