iomap: move the direct IO code into a separate file
Move the direct IO code into a separate file so that we can group related functions in a single file instead of having a single enormous source file. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong
parent
56a178981d
commit
db074436f4
554
fs/iomap.c
554
fs/iomap.c
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@ -90,12 +90,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
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return written ? written : ret;
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}
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static sector_t
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iomap_sector(struct iomap *iomap, loff_t pos)
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{
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return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
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}
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static struct iomap_page *
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iomap_page_create(struct inode *inode, struct page *page)
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{
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@ -1148,551 +1142,3 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
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return block_page_mkwrite_return(ret);
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}
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EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
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/*
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* Private flags for iomap_dio, must not overlap with the public ones in
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* iomap.h:
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*/
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#define IOMAP_DIO_WRITE_FUA (1 << 28)
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#define IOMAP_DIO_NEED_SYNC (1 << 29)
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#define IOMAP_DIO_WRITE (1 << 30)
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#define IOMAP_DIO_DIRTY (1 << 31)
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struct iomap_dio {
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struct kiocb *iocb;
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iomap_dio_end_io_t *end_io;
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loff_t i_size;
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loff_t size;
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atomic_t ref;
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unsigned flags;
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int error;
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bool wait_for_completion;
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union {
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/* used during submission and for synchronous completion: */
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struct {
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struct iov_iter *iter;
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struct task_struct *waiter;
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struct request_queue *last_queue;
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blk_qc_t cookie;
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} submit;
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/* used for aio completion: */
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struct {
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struct work_struct work;
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} aio;
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};
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};
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int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
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{
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struct request_queue *q = READ_ONCE(kiocb->private);
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if (!q)
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return 0;
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return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin);
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}
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EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
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static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
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struct bio *bio)
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{
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atomic_inc(&dio->ref);
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if (dio->iocb->ki_flags & IOCB_HIPRI)
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bio_set_polled(bio, dio->iocb);
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dio->submit.last_queue = bdev_get_queue(iomap->bdev);
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dio->submit.cookie = submit_bio(bio);
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}
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static ssize_t iomap_dio_complete(struct iomap_dio *dio)
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{
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struct kiocb *iocb = dio->iocb;
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struct inode *inode = file_inode(iocb->ki_filp);
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loff_t offset = iocb->ki_pos;
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ssize_t ret;
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if (dio->end_io) {
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ret = dio->end_io(iocb,
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dio->error ? dio->error : dio->size,
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dio->flags);
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} else {
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ret = dio->error;
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}
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if (likely(!ret)) {
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ret = dio->size;
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/* check for short read */
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if (offset + ret > dio->i_size &&
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!(dio->flags & IOMAP_DIO_WRITE))
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ret = dio->i_size - offset;
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iocb->ki_pos += ret;
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}
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/*
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* Try again to invalidate clean pages which might have been cached by
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* non-direct readahead, or faulted in by get_user_pages() if the source
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* of the write was an mmap'ed region of the file we're writing. Either
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* one is a pretty crazy thing to do, so we don't support it 100%. If
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* this invalidation fails, tough, the write still worked...
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*
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* And this page cache invalidation has to be after dio->end_io(), as
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* some filesystems convert unwritten extents to real allocations in
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* end_io() when necessary, otherwise a racing buffer read would cache
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* zeros from unwritten extents.
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*/
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if (!dio->error &&
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(dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) {
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int err;
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err = invalidate_inode_pages2_range(inode->i_mapping,
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offset >> PAGE_SHIFT,
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(offset + dio->size - 1) >> PAGE_SHIFT);
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if (err)
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dio_warn_stale_pagecache(iocb->ki_filp);
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}
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/*
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* If this is a DSYNC write, make sure we push it to stable storage now
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* that we've written data.
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*/
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if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC))
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ret = generic_write_sync(iocb, ret);
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inode_dio_end(file_inode(iocb->ki_filp));
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kfree(dio);
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return ret;
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}
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static void iomap_dio_complete_work(struct work_struct *work)
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{
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struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work);
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struct kiocb *iocb = dio->iocb;
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iocb->ki_complete(iocb, iomap_dio_complete(dio), 0);
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}
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/*
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* Set an error in the dio if none is set yet. We have to use cmpxchg
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* as the submission context and the completion context(s) can race to
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* update the error.
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*/
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static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret)
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{
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cmpxchg(&dio->error, 0, ret);
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}
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static void iomap_dio_bio_end_io(struct bio *bio)
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{
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struct iomap_dio *dio = bio->bi_private;
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bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
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if (bio->bi_status)
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iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status));
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if (atomic_dec_and_test(&dio->ref)) {
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if (dio->wait_for_completion) {
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struct task_struct *waiter = dio->submit.waiter;
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WRITE_ONCE(dio->submit.waiter, NULL);
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blk_wake_io_task(waiter);
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} else if (dio->flags & IOMAP_DIO_WRITE) {
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struct inode *inode = file_inode(dio->iocb->ki_filp);
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INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
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queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
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} else {
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iomap_dio_complete_work(&dio->aio.work);
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}
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}
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if (should_dirty) {
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bio_check_pages_dirty(bio);
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} else {
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bio_release_pages(bio, false);
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bio_put(bio);
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}
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}
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static void
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iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
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unsigned len)
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{
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struct page *page = ZERO_PAGE(0);
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int flags = REQ_SYNC | REQ_IDLE;
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struct bio *bio;
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bio = bio_alloc(GFP_KERNEL, 1);
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bio_set_dev(bio, iomap->bdev);
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bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
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bio->bi_private = dio;
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bio->bi_end_io = iomap_dio_bio_end_io;
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get_page(page);
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__bio_add_page(bio, page, len, 0);
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bio_set_op_attrs(bio, REQ_OP_WRITE, flags);
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iomap_dio_submit_bio(dio, iomap, bio);
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}
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static loff_t
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iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
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struct iomap_dio *dio, struct iomap *iomap)
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{
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unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
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unsigned int fs_block_size = i_blocksize(inode), pad;
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unsigned int align = iov_iter_alignment(dio->submit.iter);
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struct iov_iter iter;
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struct bio *bio;
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bool need_zeroout = false;
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bool use_fua = false;
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int nr_pages, ret = 0;
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size_t copied = 0;
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if ((pos | length | align) & ((1 << blkbits) - 1))
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return -EINVAL;
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if (iomap->type == IOMAP_UNWRITTEN) {
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dio->flags |= IOMAP_DIO_UNWRITTEN;
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need_zeroout = true;
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}
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if (iomap->flags & IOMAP_F_SHARED)
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dio->flags |= IOMAP_DIO_COW;
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if (iomap->flags & IOMAP_F_NEW) {
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need_zeroout = true;
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} else if (iomap->type == IOMAP_MAPPED) {
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/*
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* Use a FUA write if we need datasync semantics, this is a pure
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* data IO that doesn't require any metadata updates (including
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* after IO completion such as unwritten extent conversion) and
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* the underlying device supports FUA. This allows us to avoid
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* cache flushes on IO completion.
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*/
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if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) &&
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(dio->flags & IOMAP_DIO_WRITE_FUA) &&
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blk_queue_fua(bdev_get_queue(iomap->bdev)))
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use_fua = true;
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}
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/*
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* Operate on a partial iter trimmed to the extent we were called for.
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* We'll update the iter in the dio once we're done with this extent.
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*/
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iter = *dio->submit.iter;
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iov_iter_truncate(&iter, length);
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nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
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if (nr_pages <= 0)
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return nr_pages;
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if (need_zeroout) {
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/* zero out from the start of the block to the write offset */
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pad = pos & (fs_block_size - 1);
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if (pad)
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iomap_dio_zero(dio, iomap, pos - pad, pad);
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}
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do {
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size_t n;
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if (dio->error) {
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iov_iter_revert(dio->submit.iter, copied);
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return 0;
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}
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bio = bio_alloc(GFP_KERNEL, nr_pages);
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bio_set_dev(bio, iomap->bdev);
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bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
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bio->bi_write_hint = dio->iocb->ki_hint;
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bio->bi_ioprio = dio->iocb->ki_ioprio;
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bio->bi_private = dio;
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bio->bi_end_io = iomap_dio_bio_end_io;
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ret = bio_iov_iter_get_pages(bio, &iter);
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if (unlikely(ret)) {
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/*
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* We have to stop part way through an IO. We must fall
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* through to the sub-block tail zeroing here, otherwise
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* this short IO may expose stale data in the tail of
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* the block we haven't written data to.
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*/
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bio_put(bio);
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goto zero_tail;
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}
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n = bio->bi_iter.bi_size;
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if (dio->flags & IOMAP_DIO_WRITE) {
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bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
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if (use_fua)
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bio->bi_opf |= REQ_FUA;
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else
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dio->flags &= ~IOMAP_DIO_WRITE_FUA;
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task_io_account_write(n);
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} else {
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bio->bi_opf = REQ_OP_READ;
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if (dio->flags & IOMAP_DIO_DIRTY)
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bio_set_pages_dirty(bio);
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}
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iov_iter_advance(dio->submit.iter, n);
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dio->size += n;
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pos += n;
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copied += n;
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nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
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iomap_dio_submit_bio(dio, iomap, bio);
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} while (nr_pages);
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/*
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* We need to zeroout the tail of a sub-block write if the extent type
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* requires zeroing or the write extends beyond EOF. If we don't zero
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* the block tail in the latter case, we can expose stale data via mmap
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* reads of the EOF block.
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*/
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zero_tail:
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if (need_zeroout ||
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((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) {
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/* zero out from the end of the write to the end of the block */
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pad = pos & (fs_block_size - 1);
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if (pad)
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iomap_dio_zero(dio, iomap, pos, fs_block_size - pad);
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}
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return copied ? copied : ret;
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}
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static loff_t
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iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
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{
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length = iov_iter_zero(length, dio->submit.iter);
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dio->size += length;
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return length;
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}
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static loff_t
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iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
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struct iomap_dio *dio, struct iomap *iomap)
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{
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struct iov_iter *iter = dio->submit.iter;
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size_t copied;
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BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
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if (dio->flags & IOMAP_DIO_WRITE) {
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loff_t size = inode->i_size;
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if (pos > size)
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memset(iomap->inline_data + size, 0, pos - size);
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copied = copy_from_iter(iomap->inline_data + pos, length, iter);
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if (copied) {
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if (pos + copied > size)
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i_size_write(inode, pos + copied);
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mark_inode_dirty(inode);
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}
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} else {
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copied = copy_to_iter(iomap->inline_data + pos, length, iter);
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}
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dio->size += copied;
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return copied;
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}
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static loff_t
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iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
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void *data, struct iomap *iomap)
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{
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struct iomap_dio *dio = data;
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switch (iomap->type) {
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case IOMAP_HOLE:
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if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
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return -EIO;
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return iomap_dio_hole_actor(length, dio);
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case IOMAP_UNWRITTEN:
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if (!(dio->flags & IOMAP_DIO_WRITE))
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return iomap_dio_hole_actor(length, dio);
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return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
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case IOMAP_MAPPED:
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return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
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case IOMAP_INLINE:
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return iomap_dio_inline_actor(inode, pos, length, dio, iomap);
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default:
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WARN_ON_ONCE(1);
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return -EIO;
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}
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}
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/*
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* iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO
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* is being issued as AIO or not. This allows us to optimise pure data writes
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* to use REQ_FUA rather than requiring generic_write_sync() to issue a
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* REQ_FLUSH post write. This is slightly tricky because a single request here
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* can be mapped into multiple disjoint IOs and only a subset of the IOs issued
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* may be pure data writes. In that case, we still need to do a full data sync
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* completion.
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*/
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ssize_t
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iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
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const struct iomap_ops *ops, iomap_dio_end_io_t end_io)
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{
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struct address_space *mapping = iocb->ki_filp->f_mapping;
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struct inode *inode = file_inode(iocb->ki_filp);
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size_t count = iov_iter_count(iter);
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loff_t pos = iocb->ki_pos, start = pos;
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loff_t end = iocb->ki_pos + count - 1, ret = 0;
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unsigned int flags = IOMAP_DIRECT;
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bool wait_for_completion = is_sync_kiocb(iocb);
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struct blk_plug plug;
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struct iomap_dio *dio;
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lockdep_assert_held(&inode->i_rwsem);
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if (!count)
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return 0;
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dio = kmalloc(sizeof(*dio), GFP_KERNEL);
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if (!dio)
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return -ENOMEM;
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dio->iocb = iocb;
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atomic_set(&dio->ref, 1);
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dio->size = 0;
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dio->i_size = i_size_read(inode);
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dio->end_io = end_io;
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dio->error = 0;
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dio->flags = 0;
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dio->submit.iter = iter;
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dio->submit.waiter = current;
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dio->submit.cookie = BLK_QC_T_NONE;
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dio->submit.last_queue = NULL;
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if (iov_iter_rw(iter) == READ) {
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if (pos >= dio->i_size)
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goto out_free_dio;
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|
||||
if (iter_is_iovec(iter) && iov_iter_rw(iter) == READ)
|
||||
dio->flags |= IOMAP_DIO_DIRTY;
|
||||
} else {
|
||||
flags |= IOMAP_WRITE;
|
||||
dio->flags |= IOMAP_DIO_WRITE;
|
||||
|
||||
/* for data sync or sync, we need sync completion processing */
|
||||
if (iocb->ki_flags & IOCB_DSYNC)
|
||||
dio->flags |= IOMAP_DIO_NEED_SYNC;
|
||||
|
||||
/*
|
||||
* For datasync only writes, we optimistically try using FUA for
|
||||
* this IO. Any non-FUA write that occurs will clear this flag,
|
||||
* hence we know before completion whether a cache flush is
|
||||
* necessary.
|
||||
*/
|
||||
if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC)
|
||||
dio->flags |= IOMAP_DIO_WRITE_FUA;
|
||||
}
|
||||
|
||||
if (iocb->ki_flags & IOCB_NOWAIT) {
|
||||
if (filemap_range_has_page(mapping, start, end)) {
|
||||
ret = -EAGAIN;
|
||||
goto out_free_dio;
|
||||
}
|
||||
flags |= IOMAP_NOWAIT;
|
||||
}
|
||||
|
||||
ret = filemap_write_and_wait_range(mapping, start, end);
|
||||
if (ret)
|
||||
goto out_free_dio;
|
||||
|
||||
/*
|
||||
* Try to invalidate cache pages for the range we're direct
|
||||
* writing. If this invalidation fails, tough, the write will
|
||||
* still work, but racing two incompatible write paths is a
|
||||
* pretty crazy thing to do, so we don't support it 100%.
|
||||
*/
|
||||
ret = invalidate_inode_pages2_range(mapping,
|
||||
start >> PAGE_SHIFT, end >> PAGE_SHIFT);
|
||||
if (ret)
|
||||
dio_warn_stale_pagecache(iocb->ki_filp);
|
||||
ret = 0;
|
||||
|
||||
if (iov_iter_rw(iter) == WRITE && !wait_for_completion &&
|
||||
!inode->i_sb->s_dio_done_wq) {
|
||||
ret = sb_init_dio_done_wq(inode->i_sb);
|
||||
if (ret < 0)
|
||||
goto out_free_dio;
|
||||
}
|
||||
|
||||
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) {
|
||||
wait_for_completion = true;
|
||||
ret = 0;
|
||||
}
|
||||
break;
|
||||
}
|
||||
pos += ret;
|
||||
|
||||
if (iov_iter_rw(iter) == READ && pos >= dio->i_size)
|
||||
break;
|
||||
} while ((count = iov_iter_count(iter)) > 0);
|
||||
blk_finish_plug(&plug);
|
||||
|
||||
if (ret < 0)
|
||||
iomap_dio_set_error(dio, ret);
|
||||
|
||||
/*
|
||||
* If all the writes we issued were FUA, we don't need to flush the
|
||||
* cache on IO completion. Clear the sync flag for this case.
|
||||
*/
|
||||
if (dio->flags & IOMAP_DIO_WRITE_FUA)
|
||||
dio->flags &= ~IOMAP_DIO_NEED_SYNC;
|
||||
|
||||
WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie);
|
||||
WRITE_ONCE(iocb->private, dio->submit.last_queue);
|
||||
|
||||
/*
|
||||
* We are about to drop our additional submission reference, which
|
||||
* might be the last reference to the dio. There are three three
|
||||
* different ways we can progress here:
|
||||
*
|
||||
* (a) If this is the last reference we will always complete and free
|
||||
* the dio ourselves.
|
||||
* (b) If this is not the last reference, and we serve an asynchronous
|
||||
* iocb, we must never touch the dio after the decrement, the
|
||||
* I/O completion handler will complete and free it.
|
||||
* (c) If this is not the last reference, but we serve a synchronous
|
||||
* iocb, the I/O completion handler will wake us up on the drop
|
||||
* of the final reference, and we will complete and free it here
|
||||
* after we got woken by the I/O completion handler.
|
||||
*/
|
||||
dio->wait_for_completion = wait_for_completion;
|
||||
if (!atomic_dec_and_test(&dio->ref)) {
|
||||
if (!wait_for_completion)
|
||||
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, true))
|
||||
io_schedule();
|
||||
}
|
||||
__set_current_state(TASK_RUNNING);
|
||||
}
|
||||
|
||||
return iomap_dio_complete(dio);
|
||||
|
||||
out_free_dio:
|
||||
kfree(dio);
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(iomap_dio_rw);
|
||||
|
|
|
|||
|
|
@ -6,6 +6,7 @@
|
|||
obj-$(CONFIG_FS_IOMAP) += iomap.o
|
||||
|
||||
iomap-y += \
|
||||
direct-io.o \
|
||||
fiemap.o \
|
||||
seek.o
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,562 @@
|
|||
// SPDX-License-Identifier: GPL-2.0
|
||||
/*
|
||||
* Copyright (C) 2010 Red Hat, Inc.
|
||||
* Copyright (c) 2016-2018 Christoph Hellwig.
|
||||
*/
|
||||
#include <linux/module.h>
|
||||
#include <linux/compiler.h>
|
||||
#include <linux/fs.h>
|
||||
#include <linux/iomap.h>
|
||||
#include <linux/backing-dev.h>
|
||||
#include <linux/uio.h>
|
||||
#include <linux/task_io_accounting_ops.h>
|
||||
|
||||
#include "../internal.h"
|
||||
|
||||
/*
|
||||
* Private flags for iomap_dio, must not overlap with the public ones in
|
||||
* iomap.h:
|
||||
*/
|
||||
#define IOMAP_DIO_WRITE_FUA (1 << 28)
|
||||
#define IOMAP_DIO_NEED_SYNC (1 << 29)
|
||||
#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;
|
||||
bool wait_for_completion;
|
||||
|
||||
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;
|
||||
};
|
||||
};
|
||||
|
||||
int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
|
||||
{
|
||||
struct request_queue *q = READ_ONCE(kiocb->private);
|
||||
|
||||
if (!q)
|
||||
return 0;
|
||||
return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
|
||||
|
||||
static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
|
||||
struct bio *bio)
|
||||
{
|
||||
atomic_inc(&dio->ref);
|
||||
|
||||
if (dio->iocb->ki_flags & IOCB_HIPRI)
|
||||
bio_set_polled(bio, dio->iocb);
|
||||
|
||||
dio->submit.last_queue = bdev_get_queue(iomap->bdev);
|
||||
dio->submit.cookie = submit_bio(bio);
|
||||
}
|
||||
|
||||
static ssize_t iomap_dio_complete(struct iomap_dio *dio)
|
||||
{
|
||||
struct kiocb *iocb = dio->iocb;
|
||||
struct inode *inode = file_inode(iocb->ki_filp);
|
||||
loff_t offset = iocb->ki_pos;
|
||||
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 (offset + ret > dio->i_size &&
|
||||
!(dio->flags & IOMAP_DIO_WRITE))
|
||||
ret = dio->i_size - offset;
|
||||
iocb->ki_pos += ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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...
|
||||
*
|
||||
* And this page cache invalidation has to be after dio->end_io(), as
|
||||
* some filesystems convert unwritten extents to real allocations in
|
||||
* end_io() when necessary, otherwise a racing buffer read would cache
|
||||
* zeros from unwritten extents.
|
||||
*/
|
||||
if (!dio->error &&
|
||||
(dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) {
|
||||
int err;
|
||||
err = invalidate_inode_pages2_range(inode->i_mapping,
|
||||
offset >> PAGE_SHIFT,
|
||||
(offset + dio->size - 1) >> PAGE_SHIFT);
|
||||
if (err)
|
||||
dio_warn_stale_pagecache(iocb->ki_filp);
|
||||
}
|
||||
|
||||
/*
|
||||
* If this is a DSYNC write, make sure we push it to stable storage now
|
||||
* that we've written data.
|
||||
*/
|
||||
if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC))
|
||||
ret = generic_write_sync(iocb, 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;
|
||||
|
||||
iocb->ki_complete(iocb, iomap_dio_complete(dio), 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_status)
|
||||
iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status));
|
||||
|
||||
if (atomic_dec_and_test(&dio->ref)) {
|
||||
if (dio->wait_for_completion) {
|
||||
struct task_struct *waiter = dio->submit.waiter;
|
||||
WRITE_ONCE(dio->submit.waiter, NULL);
|
||||
blk_wake_io_task(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 {
|
||||
bio_release_pages(bio, false);
|
||||
bio_put(bio);
|
||||
}
|
||||
}
|
||||
|
||||
static void
|
||||
iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
|
||||
unsigned len)
|
||||
{
|
||||
struct page *page = ZERO_PAGE(0);
|
||||
int flags = REQ_SYNC | REQ_IDLE;
|
||||
struct bio *bio;
|
||||
|
||||
bio = bio_alloc(GFP_KERNEL, 1);
|
||||
bio_set_dev(bio, iomap->bdev);
|
||||
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
|
||||
bio->bi_private = dio;
|
||||
bio->bi_end_io = iomap_dio_bio_end_io;
|
||||
|
||||
get_page(page);
|
||||
__bio_add_page(bio, page, len, 0);
|
||||
bio_set_op_attrs(bio, REQ_OP_WRITE, flags);
|
||||
iomap_dio_submit_bio(dio, iomap, bio);
|
||||
}
|
||||
|
||||
static loff_t
|
||||
iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
|
||||
struct iomap_dio *dio, struct iomap *iomap)
|
||||
{
|
||||
unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
|
||||
unsigned int fs_block_size = i_blocksize(inode), pad;
|
||||
unsigned int align = iov_iter_alignment(dio->submit.iter);
|
||||
struct iov_iter iter;
|
||||
struct bio *bio;
|
||||
bool need_zeroout = false;
|
||||
bool use_fua = false;
|
||||
int nr_pages, ret = 0;
|
||||
size_t copied = 0;
|
||||
|
||||
if ((pos | length | align) & ((1 << blkbits) - 1))
|
||||
return -EINVAL;
|
||||
|
||||
if (iomap->type == IOMAP_UNWRITTEN) {
|
||||
dio->flags |= IOMAP_DIO_UNWRITTEN;
|
||||
need_zeroout = true;
|
||||
}
|
||||
|
||||
if (iomap->flags & IOMAP_F_SHARED)
|
||||
dio->flags |= IOMAP_DIO_COW;
|
||||
|
||||
if (iomap->flags & IOMAP_F_NEW) {
|
||||
need_zeroout = true;
|
||||
} else if (iomap->type == IOMAP_MAPPED) {
|
||||
/*
|
||||
* Use a FUA write if we need datasync semantics, this is a pure
|
||||
* data IO that doesn't require any metadata updates (including
|
||||
* after IO completion such as unwritten extent conversion) and
|
||||
* the underlying device supports FUA. This allows us to avoid
|
||||
* cache flushes on IO completion.
|
||||
*/
|
||||
if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) &&
|
||||
(dio->flags & IOMAP_DIO_WRITE_FUA) &&
|
||||
blk_queue_fua(bdev_get_queue(iomap->bdev)))
|
||||
use_fua = true;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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 {
|
||||
size_t n;
|
||||
if (dio->error) {
|
||||
iov_iter_revert(dio->submit.iter, copied);
|
||||
return 0;
|
||||
}
|
||||
|
||||
bio = bio_alloc(GFP_KERNEL, nr_pages);
|
||||
bio_set_dev(bio, iomap->bdev);
|
||||
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
|
||||
bio->bi_write_hint = dio->iocb->ki_hint;
|
||||
bio->bi_ioprio = dio->iocb->ki_ioprio;
|
||||
bio->bi_private = dio;
|
||||
bio->bi_end_io = iomap_dio_bio_end_io;
|
||||
|
||||
ret = bio_iov_iter_get_pages(bio, &iter);
|
||||
if (unlikely(ret)) {
|
||||
/*
|
||||
* We have to stop part way through an IO. We must fall
|
||||
* through to the sub-block tail zeroing here, otherwise
|
||||
* this short IO may expose stale data in the tail of
|
||||
* the block we haven't written data to.
|
||||
*/
|
||||
bio_put(bio);
|
||||
goto zero_tail;
|
||||
}
|
||||
|
||||
n = bio->bi_iter.bi_size;
|
||||
if (dio->flags & IOMAP_DIO_WRITE) {
|
||||
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
|
||||
if (use_fua)
|
||||
bio->bi_opf |= REQ_FUA;
|
||||
else
|
||||
dio->flags &= ~IOMAP_DIO_WRITE_FUA;
|
||||
task_io_account_write(n);
|
||||
} else {
|
||||
bio->bi_opf = REQ_OP_READ;
|
||||
if (dio->flags & IOMAP_DIO_DIRTY)
|
||||
bio_set_pages_dirty(bio);
|
||||
}
|
||||
|
||||
iov_iter_advance(dio->submit.iter, n);
|
||||
|
||||
dio->size += n;
|
||||
pos += n;
|
||||
copied += n;
|
||||
|
||||
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
|
||||
iomap_dio_submit_bio(dio, iomap, bio);
|
||||
} while (nr_pages);
|
||||
|
||||
/*
|
||||
* We need to zeroout the tail of a sub-block write if the extent type
|
||||
* requires zeroing or the write extends beyond EOF. If we don't zero
|
||||
* the block tail in the latter case, we can expose stale data via mmap
|
||||
* reads of the EOF block.
|
||||
*/
|
||||
zero_tail:
|
||||
if (need_zeroout ||
|
||||
((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) {
|
||||
/* 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);
|
||||
}
|
||||
return copied ? copied : ret;
|
||||
}
|
||||
|
||||
static loff_t
|
||||
iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
|
||||
{
|
||||
length = iov_iter_zero(length, dio->submit.iter);
|
||||
dio->size += length;
|
||||
return length;
|
||||
}
|
||||
|
||||
static loff_t
|
||||
iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
|
||||
struct iomap_dio *dio, struct iomap *iomap)
|
||||
{
|
||||
struct iov_iter *iter = dio->submit.iter;
|
||||
size_t copied;
|
||||
|
||||
BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
|
||||
|
||||
if (dio->flags & IOMAP_DIO_WRITE) {
|
||||
loff_t size = inode->i_size;
|
||||
|
||||
if (pos > size)
|
||||
memset(iomap->inline_data + size, 0, pos - size);
|
||||
copied = copy_from_iter(iomap->inline_data + pos, length, iter);
|
||||
if (copied) {
|
||||
if (pos + copied > size)
|
||||
i_size_write(inode, pos + copied);
|
||||
mark_inode_dirty(inode);
|
||||
}
|
||||
} else {
|
||||
copied = copy_to_iter(iomap->inline_data + pos, length, iter);
|
||||
}
|
||||
dio->size += copied;
|
||||
return copied;
|
||||
}
|
||||
|
||||
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;
|
||||
|
||||
switch (iomap->type) {
|
||||
case IOMAP_HOLE:
|
||||
if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
|
||||
return -EIO;
|
||||
return iomap_dio_hole_actor(length, dio);
|
||||
case IOMAP_UNWRITTEN:
|
||||
if (!(dio->flags & IOMAP_DIO_WRITE))
|
||||
return iomap_dio_hole_actor(length, dio);
|
||||
return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
|
||||
case IOMAP_MAPPED:
|
||||
return iomap_dio_bio_actor(inode, pos, length, dio, iomap);
|
||||
case IOMAP_INLINE:
|
||||
return iomap_dio_inline_actor(inode, pos, length, dio, iomap);
|
||||
default:
|
||||
WARN_ON_ONCE(1);
|
||||
return -EIO;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO
|
||||
* is being issued as AIO or not. This allows us to optimise pure data writes
|
||||
* to use REQ_FUA rather than requiring generic_write_sync() to issue a
|
||||
* REQ_FLUSH post write. This is slightly tricky because a single request here
|
||||
* can be mapped into multiple disjoint IOs and only a subset of the IOs issued
|
||||
* may be pure data writes. In that case, we still need to do a full data sync
|
||||
* completion.
|
||||
*/
|
||||
ssize_t
|
||||
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
|
||||
const 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, start = pos;
|
||||
loff_t end = iocb->ki_pos + count - 1, ret = 0;
|
||||
unsigned int flags = IOMAP_DIRECT;
|
||||
bool wait_for_completion = is_sync_kiocb(iocb);
|
||||
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;
|
||||
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_is_iovec(iter) && iov_iter_rw(iter) == READ)
|
||||
dio->flags |= IOMAP_DIO_DIRTY;
|
||||
} else {
|
||||
flags |= IOMAP_WRITE;
|
||||
dio->flags |= IOMAP_DIO_WRITE;
|
||||
|
||||
/* for data sync or sync, we need sync completion processing */
|
||||
if (iocb->ki_flags & IOCB_DSYNC)
|
||||
dio->flags |= IOMAP_DIO_NEED_SYNC;
|
||||
|
||||
/*
|
||||
* For datasync only writes, we optimistically try using FUA for
|
||||
* this IO. Any non-FUA write that occurs will clear this flag,
|
||||
* hence we know before completion whether a cache flush is
|
||||
* necessary.
|
||||
*/
|
||||
if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC)
|
||||
dio->flags |= IOMAP_DIO_WRITE_FUA;
|
||||
}
|
||||
|
||||
if (iocb->ki_flags & IOCB_NOWAIT) {
|
||||
if (filemap_range_has_page(mapping, start, end)) {
|
||||
ret = -EAGAIN;
|
||||
goto out_free_dio;
|
||||
}
|
||||
flags |= IOMAP_NOWAIT;
|
||||
}
|
||||
|
||||
ret = filemap_write_and_wait_range(mapping, start, end);
|
||||
if (ret)
|
||||
goto out_free_dio;
|
||||
|
||||
/*
|
||||
* Try to invalidate cache pages for the range we're direct
|
||||
* writing. If this invalidation fails, tough, the write will
|
||||
* still work, but racing two incompatible write paths is a
|
||||
* pretty crazy thing to do, so we don't support it 100%.
|
||||
*/
|
||||
ret = invalidate_inode_pages2_range(mapping,
|
||||
start >> PAGE_SHIFT, end >> PAGE_SHIFT);
|
||||
if (ret)
|
||||
dio_warn_stale_pagecache(iocb->ki_filp);
|
||||
ret = 0;
|
||||
|
||||
if (iov_iter_rw(iter) == WRITE && !wait_for_completion &&
|
||||
!inode->i_sb->s_dio_done_wq) {
|
||||
ret = sb_init_dio_done_wq(inode->i_sb);
|
||||
if (ret < 0)
|
||||
goto out_free_dio;
|
||||
}
|
||||
|
||||
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) {
|
||||
wait_for_completion = true;
|
||||
ret = 0;
|
||||
}
|
||||
break;
|
||||
}
|
||||
pos += ret;
|
||||
|
||||
if (iov_iter_rw(iter) == READ && pos >= dio->i_size)
|
||||
break;
|
||||
} while ((count = iov_iter_count(iter)) > 0);
|
||||
blk_finish_plug(&plug);
|
||||
|
||||
if (ret < 0)
|
||||
iomap_dio_set_error(dio, ret);
|
||||
|
||||
/*
|
||||
* If all the writes we issued were FUA, we don't need to flush the
|
||||
* cache on IO completion. Clear the sync flag for this case.
|
||||
*/
|
||||
if (dio->flags & IOMAP_DIO_WRITE_FUA)
|
||||
dio->flags &= ~IOMAP_DIO_NEED_SYNC;
|
||||
|
||||
WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie);
|
||||
WRITE_ONCE(iocb->private, dio->submit.last_queue);
|
||||
|
||||
/*
|
||||
* We are about to drop our additional submission reference, which
|
||||
* might be the last reference to the dio. There are three three
|
||||
* different ways we can progress here:
|
||||
*
|
||||
* (a) If this is the last reference we will always complete and free
|
||||
* the dio ourselves.
|
||||
* (b) If this is not the last reference, and we serve an asynchronous
|
||||
* iocb, we must never touch the dio after the decrement, the
|
||||
* I/O completion handler will complete and free it.
|
||||
* (c) If this is not the last reference, but we serve a synchronous
|
||||
* iocb, the I/O completion handler will wake us up on the drop
|
||||
* of the final reference, and we will complete and free it here
|
||||
* after we got woken by the I/O completion handler.
|
||||
*/
|
||||
dio->wait_for_completion = wait_for_completion;
|
||||
if (!atomic_dec_and_test(&dio->ref)) {
|
||||
if (!wait_for_completion)
|
||||
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, true))
|
||||
io_schedule();
|
||||
}
|
||||
__set_current_state(TASK_RUNNING);
|
||||
}
|
||||
|
||||
return iomap_dio_complete(dio);
|
||||
|
||||
out_free_dio:
|
||||
kfree(dio);
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(iomap_dio_rw);
|
||||
|
|
@ -7,6 +7,7 @@
|
|||
#include <linux/mm.h>
|
||||
#include <linux/types.h>
|
||||
#include <linux/mm_types.h>
|
||||
#include <linux/blkdev.h>
|
||||
|
||||
struct address_space;
|
||||
struct fiemap_extent_info;
|
||||
|
|
@ -69,6 +70,12 @@ struct iomap {
|
|||
const struct iomap_page_ops *page_ops;
|
||||
};
|
||||
|
||||
static inline sector_t
|
||||
iomap_sector(struct iomap *iomap, loff_t pos)
|
||||
{
|
||||
return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
|
||||
}
|
||||
|
||||
/*
|
||||
* When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
|
||||
* and page_done will be called for each page written to. This only applies to
|
||||
|
|
|
|||
Loading…
Reference in New Issue