On Fri, Feb 26, 2021 at 08:20:27AM +0800, Shiyang Ruan wrote:
> Some operations, such as comparing a range of data in two files under
> fsdax mode, requires nested iomap_open()/iomap_end() on two file. Thus,
> we introduce iomap_apply2() to accept arguments from two files and
> iomap_actor2_t for actions on two files.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
> ---
> fs/iomap/apply.c | 51 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/iomap.h | 7 +++++-
> 2 files changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
> index 26ab6563181f..fd2f8bde5791 100644
> --- a/fs/iomap/apply.c
> +++ b/fs/iomap/apply.c
> @@ -97,3 +97,54 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
>
> return written ? written : ret;
> }
> +
> +loff_t
> +iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2, loff_t pos2,
> + loff_t length, unsigned int flags, const struct iomap_ops *ops,
> + void *data, iomap_actor2_t actor)
> +{
> + struct iomap smap = { .type = IOMAP_HOLE };
> + struct iomap dmap = { .type = IOMAP_HOLE };
> + loff_t written = 0, ret;
> +
> + ret = ops->iomap_begin(ino1, pos1, length, 0, &smap, NULL);
> + if (ret)
> + goto out_src;
> + if (WARN_ON(smap.offset > pos1)) {
> + written = -EIO;
> + goto out_src;
> + }
> + if (WARN_ON(smap.length == 0)) {
> + written = -EIO;
> + goto out_src;
> + }
> +
> + ret = ops->iomap_begin(ino2, pos2, length, 0, &dmap, NULL);
> + if (ret)
> + goto out_dest;
> + if (WARN_ON(dmap.offset > pos2)) {
> + written = -EIO;
> + goto out_dest;
> + }
> + if (WARN_ON(dmap.length == 0)) {
> + written = -EIO;
> + goto out_dest;
> + }
> +
> + /* make sure extent length of two file is equal */
> + if (WARN_ON(smap.length != dmap.length)) {
Why not set smap.length and dmap.length to min(smap.length, dmap.length) ?
--D
> + written = -EIO;
> + goto out_dest;
> + }
> +
> + written = actor(ino1, pos1, ino2, pos2, length, data, &smap, &dmap);
> +
> +out_dest:
> + if (ops->iomap_end)
> + ret = ops->iomap_end(ino2, pos2, length, 0, 0, &dmap);
> +out_src:
> + if (ops->iomap_end)
> + ret = ops->iomap_end(ino1, pos1, length, 0, 0, &smap);
> +
> + return ret;
> +}
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 5bd3cac4df9c..913f98897a77 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -148,10 +148,15 @@ struct iomap_ops {
> */
> typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
> void *data, struct iomap *iomap, struct iomap *srcmap);
> -
> +typedef loff_t (*iomap_actor2_t)(struct inode *ino1, loff_t pos1,
> + struct inode *ino2, loff_t pos2, loff_t len, void *data,
> + struct iomap *smap, struct iomap *dmap);
> loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
> unsigned flags, const struct iomap_ops *ops, void *data,
> iomap_actor_t actor);
> +loff_t iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2,
> + loff_t pos2, loff_t length, unsigned int flags,
> + const struct iomap_ops *ops, void *data, iomap_actor2_t actor);
>
> ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
> const struct iomap_ops *ops);
> --
> 2.30.1
>
>
>
