> On Jun 1, 2023, at 5:56 AM, Damien Le Moal <dlemoal@xxxxxxxxxx> wrote:
>
> Remove the function zonefs_file_dio_append() that is used to manually
> issue REQ_OP_ZONE_APPEND BIOs for processing synchronous direct writes
> and use iomap instead.
>
> To preserve the use of zone append operations for synchronous writes,
> different struct iomap_dio_ops are defined. For synchronous direct
> writes using zone append, zonefs_zone_append_dio_ops is introduced.
> The submit_bio operation of this structure is defined as the function
> zonefs_file_zone_append_dio_submit_io() which is used to change the BIO
> opreation for synchronous direct IO writes to REQ_OP_ZONE_APPEND.
>
> In order to preserve the write location check on completion of zone
> append BIOs, the end_io operation is also defined using the function
> zonefs_file_zone_append_dio_bio_end_io(). This check now relies on the
> zonefs_zone_append_bio structure, allocated together with zone append
> BIOs with a dedicated BIO set. This structure include the target inode
> of a zone append BIO as well as the target append offset location for
> the zone append operation. This is used to perform a check against
> bio->bi_iter.bi_sector when the BIO completes, without needing to use
> the zone information z_wpoffset field, thus removing the need for
> taking the inode truncate mutex.
>
> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
>
> Changes from v1:
> * Renamed a few things (iomap operations, zonefs bio set, ...)
> * Restrict the use of the bio set to zone append synchronous writes
>
> fs/zonefs/file.c | 206 ++++++++++++++++++++++++---------------------
> fs/zonefs/super.c | 9 +-
> fs/zonefs/zonefs.h | 2 +
> 3 files changed, 120 insertions(+), 97 deletions(-)
>
> diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
> index 132f01d3461f..c34ec5b54053 100644
> --- a/fs/zonefs/file.c
> +++ b/fs/zonefs/file.c
> @@ -342,6 +342,77 @@ static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
> return generic_file_llseek_size(file, offset, whence, isize, isize);
> }
>
> +struct zonefs_zone_append_bio {
> + /* The target inode of the BIO */
> + struct inode *inode;
> +
> + /* For sync writes, the target append write offset */
> + u64 append_offset;
> +
> + /*
> + * This member must come last, bio_alloc_bioset will allocate enough
> + * bytes for entire zonefs_bio but relies on bio being last.
> + */
> + struct bio bio;
> +};
> +
> +static inline struct zonefs_zone_append_bio *
> +zonefs_zone_append_bio(struct bio *bio)
> +{
> + return container_of(bio, struct zonefs_zone_append_bio, bio);
> +}
> +
> +static void zonefs_file_zone_append_dio_bio_end_io(struct bio *bio)
> +{
> + struct zonefs_zone_append_bio *za_bio = zonefs_zone_append_bio(bio);
> + struct zonefs_zone *z = zonefs_inode_zone(za_bio->inode);
> + sector_t za_sector;
> +
> + if (bio->bi_status != BLK_STS_OK)
> + goto bio_end;
> +
> + /*
> + * If the file zone was written underneath the file system, the zone
> + * append operation can still succedd (if the zone is not full) but
> + * the write append location will not be where we expect it to be.
> + * Check that we wrote where we intended to, that is, at z->z_wpoffset.
> + */
> + za_sector = z->z_sector + (za_bio->append_offset >> SECTOR_SHIFT);
> + if (bio->bi_iter.bi_sector != za_sector) {
> + zonefs_warn(za_bio->inode->i_sb,
> + "Invalid write sector %llu for zone at %llu\n",
> + bio->bi_iter.bi_sector, z->z_sector);
> + bio->bi_status = BLK_STS_IOERR;
> + }
> +
> +bio_end:
> + iomap_dio_bio_end_io(bio);
> +}
> +
> +static void zonefs_file_zone_append_dio_submit_io(const struct iomap_iter *iter,
> + struct bio *bio,
> + loff_t file_offset)
> +{
> + struct zonefs_zone_append_bio *za_bio = zonefs_zone_append_bio(bio);
> + struct inode *inode = iter->inode;
> + struct zonefs_zone *z = zonefs_inode_zone(inode);
> +
> + /*
> + * Issue a zone append BIO to process sync dio writes. The append
> + * file offset is saved to check the zone append write location
> + * on completion of the BIO.
> + */
> + za_bio->inode = inode;
> + za_bio->append_offset = file_offset;
> +
> + bio->bi_opf &= ~REQ_OP_WRITE;
> + bio->bi_opf |= REQ_OP_ZONE_APPEND;
> + bio->bi_iter.bi_sector = z->z_sector;
> + bio->bi_end_io = zonefs_file_zone_append_dio_bio_end_io;
> +
> + submit_bio(bio);
> +}
> +
> static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
> int error, unsigned int flags)
> {
> @@ -372,93 +443,17 @@ static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
> return 0;
> }
>
> -static const struct iomap_dio_ops zonefs_write_dio_ops = {
> - .end_io = zonefs_file_write_dio_end_io,
> -};
> +static struct bio_set zonefs_zone_append_bio_set;
>
> -static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
> -{
> - struct inode *inode = file_inode(iocb->ki_filp);
> - struct zonefs_zone *z = zonefs_inode_zone(inode);
> - struct block_device *bdev = inode->i_sb->s_bdev;
> - unsigned int max = bdev_max_zone_append_sectors(bdev);
> - pgoff_t start, end;
> - struct bio *bio;
> - ssize_t size = 0;
> - int nr_pages;
> - ssize_t ret;
> -
> - max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
> - iov_iter_truncate(from, max);
> -
> - /*
> - * If the inode block size (zone write granularity) is smaller than the
> - * page size, we may be appending data belonging to the last page of the
> - * inode straddling inode->i_size, with that page already cached due to
> - * a buffered read or readahead. So make sure to invalidate that page.
> - * This will always be a no-op for the case where the block size is
> - * equal to the page size.
> - */
> - start = iocb->ki_pos >> PAGE_SHIFT;
> - end = (iocb->ki_pos + iov_iter_count(from) - 1) >> PAGE_SHIFT;
> - if (invalidate_inode_pages2_range(inode->i_mapping, start, end))
> - return -EBUSY;
> -
> - nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
> - if (!nr_pages)
> - return 0;
> -
> - bio = bio_alloc(bdev, nr_pages,
> - REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE, GFP_NOFS);
> - bio->bi_iter.bi_sector = z->z_sector;
> - bio->bi_ioprio = iocb->ki_ioprio;
> - if (iocb_is_dsync(iocb))
> - bio->bi_opf |= REQ_FUA;
> -
> - ret = bio_iov_iter_get_pages(bio, from);
> - if (unlikely(ret))
> - goto out_release;
> -
> - size = bio->bi_iter.bi_size;
> - task_io_account_write(size);
> -
> - if (iocb->ki_flags & IOCB_HIPRI)
> - bio_set_polled(bio, iocb);
> -
> - ret = submit_bio_wait(bio);
> -
> - /*
> - * If the file zone was written underneath the file system, the zone
> - * write pointer may not be where we expect it to be, but the zone
> - * append write can still succeed. So check manually that we wrote where
> - * we intended to, that is, at zi->i_wpoffset.
> - */
> - if (!ret) {
> - sector_t wpsector =
> - z->z_sector + (z->z_wpoffset >> SECTOR_SHIFT);
> -
> - if (bio->bi_iter.bi_sector != wpsector) {
> - zonefs_warn(inode->i_sb,
> - "Corrupted write pointer %llu for zone at %llu\n",
> - bio->bi_iter.bi_sector, z->z_sector);
> - ret = -EIO;
> - }
> - }
> -
> - zonefs_file_write_dio_end_io(iocb, size, ret, 0);
> - trace_zonefs_file_dio_append(inode, size, ret);
> -
> -out_release:
> - bio_release_pages(bio, false);
> - bio_put(bio);
> -
> - if (ret >= 0) {
> - iocb->ki_pos += size;
> - return size;
> - }
> +static const struct iomap_dio_ops zonefs_zone_append_dio_ops = {
> + .submit_io = zonefs_file_zone_append_dio_submit_io,
> + .end_io = zonefs_file_write_dio_end_io,
> + .bio_set = &zonefs_zone_append_bio_set,
> +};
>
> - return ret;
> -}
> +static const struct iomap_dio_ops zonefs_write_dio_ops = {
> + .end_io = zonefs_file_write_dio_end_io,
> +};
>
> /*
> * Do not exceed the LFS limits nor the file zone size. If pos is under the
> @@ -539,6 +534,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> struct zonefs_inode_info *zi = ZONEFS_I(inode);
> struct zonefs_zone *z = zonefs_inode_zone(inode);
> struct super_block *sb = inode->i_sb;
> + const struct iomap_dio_ops *dio_ops;
> bool sync = is_sync_kiocb(iocb);
> bool append = false;
> ssize_t ret, count;
> @@ -582,20 +578,26 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> }
>
> if (append) {
> - ret = zonefs_file_dio_append(iocb, from);
> + unsigned int max = bdev_max_zone_append_sectors(sb->s_bdev);
> +
> + max = ALIGN_DOWN(max << SECTOR_SHIFT, sb->s_blocksize);
> + iov_iter_truncate(from, max);
> +
> + dio_ops = &zonefs_zone_append_dio_ops;
> } else {
> - /*
> - * iomap_dio_rw() may return ENOTBLK if there was an issue with
> - * page invalidation. Overwrite that error code with EBUSY to
> - * be consistent with zonefs_file_dio_append() return value for
> - * similar issues.
> - */
> - ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
> - &zonefs_write_dio_ops, 0, NULL, 0);
> - if (ret == -ENOTBLK)
> - ret = -EBUSY;
> + dio_ops = &zonefs_write_dio_ops;
> }
>
> + /*
> + * iomap_dio_rw() may return ENOTBLK if there was an issue with
> + * page invalidation. Overwrite that error code with EBUSY so that
> + * the user can make sense of the error.
> + */
> + ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
> + dio_ops, 0, NULL, 0);
> + if (ret == -ENOTBLK)
> + ret = -EBUSY;
> +
> if (zonefs_zone_is_seq(z) &&
> (ret > 0 || ret == -EIOCBQUEUED)) {
> if (ret > 0)
> @@ -900,3 +902,15 @@ const struct file_operations zonefs_file_operations = {
> .splice_write = iter_file_splice_write,
> .iopoll = iocb_bio_iopoll,
> };
> +
> +int zonefs_file_bioset_init(void)
> +{
> + return bioset_init(&zonefs_zone_append_bio_set, BIO_POOL_SIZE,
> + offsetof(struct zonefs_zone_append_bio, bio),
> + BIOSET_NEED_BVECS);
> +}
> +
> +void zonefs_file_bioset_exit(void)
> +{
> + bioset_exit(&zonefs_zone_append_bio_set);
> +}
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index 23b8b299c64e..56c00111966a 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -1412,10 +1412,14 @@ static int __init zonefs_init(void)
>
> BUILD_BUG_ON(sizeof(struct zonefs_super) != ZONEFS_SUPER_SIZE);
>
> - ret = zonefs_init_inodecache();
> + ret = zonefs_file_bioset_init();
> if (ret)
> return ret;
>
> + ret = zonefs_init_inodecache();
> + if (ret)
> + goto destroy_bioset;
> +
> ret = zonefs_sysfs_init();
> if (ret)
> goto destroy_inodecache;
> @@ -1430,6 +1434,8 @@ static int __init zonefs_init(void)
> zonefs_sysfs_exit();
> destroy_inodecache:
> zonefs_destroy_inodecache();
> +destroy_bioset:
> + zonefs_file_bioset_exit();
>
> return ret;
> }
> @@ -1439,6 +1445,7 @@ static void __exit zonefs_exit(void)
> unregister_filesystem(&zonefs_type);
> zonefs_sysfs_exit();
> zonefs_destroy_inodecache();
> + zonefs_file_bioset_exit();
> }
>
> MODULE_AUTHOR("Damien Le Moal");
> diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h
> index 8175652241b5..f663b8ebc2cb 100644
> --- a/fs/zonefs/zonefs.h
> +++ b/fs/zonefs/zonefs.h
> @@ -279,6 +279,8 @@ extern const struct file_operations zonefs_dir_operations;
> extern const struct address_space_operations zonefs_file_aops;
> extern const struct file_operations zonefs_file_operations;
> int zonefs_file_truncate(struct inode *inode, loff_t isize);
> +int zonefs_file_bioset_init(void);
> +void zonefs_file_bioset_exit(void);
>
> /* In sysfs.c */
> int zonefs_sysfs_register(struct super_block *sb);
> --
> 2.40.1
>
Looks Good.
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
--
Himanshu Madhani Oracle Linux Engineering
