On 2020/04/27 20:32, Johannes Thumshirn wrote:
> Synchronous direct I/O to a sequential write only zone can be issued using
> the new REQ_OP_ZONE_APPEND request operation. As dispatching multiple
> BIOs can potentially result in reordering, we cannot support asynchronous
> IO via this interface.
>
> We also can only dispatch up to queue_max_zone_append_sectors() via the
> new zone-append method and have to return a short write back to user-space
> in case an IO larger than queue_max_zone_append_sectors() has been issued.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
> ---
> fs/zonefs/super.c | 80 ++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 72 insertions(+), 8 deletions(-)
>
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index 3ce9829a6936..0bf7009f50a2 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -20,6 +20,7 @@
> #include <linux/mman.h>
> #include <linux/sched/mm.h>
> #include <linux/crc32.h>
> +#include <linux/task_io_accounting_ops.h>
>
> #include "zonefs.h"
>
> @@ -596,6 +597,61 @@ static const struct iomap_dio_ops zonefs_write_dio_ops = {
> .end_io = zonefs_file_write_dio_end_io,
> };
>
> +static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
> +{
> + struct inode *inode = file_inode(iocb->ki_filp);
> + struct zonefs_inode_info *zi = ZONEFS_I(inode);
> + struct block_device *bdev = inode->i_sb->s_bdev;
> + unsigned int max;
> + struct bio *bio;
> + ssize_t size;
> + int nr_pages;
> + ssize_t ret;
> +
> + nr_pages = iov_iter_npages(from, BIO_MAX_PAGES);
> + if (!nr_pages)
> + return 0;
> +
> + max = queue_max_zone_append_sectors(bdev_get_queue(bdev));
> + max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
> + iov_iter_truncate(from, max);
> +
> + bio = bio_alloc_bioset(GFP_NOFS, nr_pages, &fs_bio_set);
> + if (!bio)
> + return -ENOMEM;
> +
> + bio_set_dev(bio, bdev);
> + bio->bi_iter.bi_sector = zi->i_zsector;
> + bio->bi_write_hint = iocb->ki_hint;
> + bio->bi_ioprio = iocb->ki_ioprio;
> + bio->bi_opf = REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE;
> + if (iocb->ki_flags & IOCB_DSYNC)
> + bio->bi_opf |= REQ_FUA;
> +
> + ret = bio_iov_iter_get_pages(bio, from);
> + if (unlikely(ret)) {
> + bio_io_error(bio);
> + return ret;
> + }
> + size = bio->bi_iter.bi_size;
> + task_io_account_write(ret);
> +
> + if (iocb->ki_flags & IOCB_HIPRI)
> + bio_set_polled(bio, iocb);
> +
> + ret = submit_bio_wait(bio);
> +
> + bio_put(bio);
> +
> + zonefs_file_write_dio_end_io(iocb, size, ret, 0);
> + if (ret >= 0) {
> + iocb->ki_pos += size;
> + return size;
> + }
> +
> + return ret;
> +}
> +
> /*
> * Handle direct writes. For sequential zone files, this is the only possible
> * write path. For these files, check that the user is issuing writes
> @@ -611,6 +667,8 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> struct inode *inode = file_inode(iocb->ki_filp);
> struct zonefs_inode_info *zi = ZONEFS_I(inode);
> struct super_block *sb = inode->i_sb;
> + bool sync = is_sync_kiocb(iocb);
> + bool append = false;
> size_t count;
> ssize_t ret;
>
> @@ -619,7 +677,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> * as this can cause write reordering (e.g. the first aio gets EAGAIN
> * on the inode lock but the second goes through but is now unaligned).
> */
> - if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb) &&
> + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !sync &&
> (iocb->ki_flags & IOCB_NOWAIT))
> return -EOPNOTSUPP;
>
> @@ -643,16 +701,22 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> }
>
> /* Enforce sequential writes (append only) in sequential zones */
> - mutex_lock(&zi->i_truncate_mutex);
> - if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && iocb->ki_pos != zi->i_wpoffset) {
> + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ) {
> + mutex_lock(&zi->i_truncate_mutex);
> + if (iocb->ki_pos != zi->i_wpoffset) {
> + mutex_unlock(&zi->i_truncate_mutex);
> + ret = -EINVAL;
> + goto inode_unlock;
> + }
> mutex_unlock(&zi->i_truncate_mutex);
> - ret = -EINVAL;
> - goto inode_unlock;
> + append = sync;
> }
> - mutex_unlock(&zi->i_truncate_mutex);
>
> - ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
> - &zonefs_write_dio_ops, is_sync_kiocb(iocb));
> + if (append)
> + ret = zonefs_file_dio_append(iocb, from);
> + else
> + ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
> + &zonefs_write_dio_ops, sync);
> if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
> (ret > 0 || ret == -EIOCBQUEUED)) {
> if (ret > 0)
>
Acked-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
