On Fri, Aug 29, 2025 at 04:56:25PM -0700, Joanne Koong wrote:
> Read folio data into the page cache using iomap. This gives us granular
> uptodate tracking for large folios, which optimizes how much data needs
> to be read in. If some portions of the folio are already uptodate (eg
> through a prior write), we only need to read in the non-uptodate
> portions.
>
> Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
Looks fine to me,
Reviewed-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
--D
> ---
> fs/fuse/file.c | 72 ++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 49 insertions(+), 23 deletions(-)
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 5525a4520b0f..bdfb13cdee4b 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -828,22 +828,62 @@ static int fuse_do_readfolio(struct file *file, struct folio *folio,
> return 0;
> }
>
> +static int fuse_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> + unsigned int flags, struct iomap *iomap,
> + struct iomap *srcmap)
> +{
> + iomap->type = IOMAP_MAPPED;
> + iomap->length = length;
> + iomap->offset = offset;
> + return 0;
> +}
> +
> +static const struct iomap_ops fuse_iomap_ops = {
> + .iomap_begin = fuse_iomap_begin,
> +};
> +
> +struct fuse_fill_read_data {
> + struct file *file;
> +};
> +
> +static int fuse_iomap_read_folio_range_async(const struct iomap_iter *iter,
> + struct folio *folio, loff_t pos,
> + size_t len)
> +{
> + struct fuse_fill_read_data *data = iter->private;
> + struct file *file = data->file;
> + size_t off = offset_in_folio(folio, pos);
> + int ret;
> +
> + /*
> + * for non-readahead read requests, do reads synchronously since
> + * it's not guaranteed that the server can handle out-of-order reads
> + */
> + iomap_start_folio_read(folio, len);
> + ret = fuse_do_readfolio(file, folio, off, len);
> + iomap_finish_folio_read(folio, off, len, ret);
> + return ret;
> +}
> +
> +static const struct iomap_read_ops fuse_iomap_read_ops = {
> + .read_folio_range = fuse_iomap_read_folio_range_async,
> +};
> +
> static int fuse_read_folio(struct file *file, struct folio *folio)
> {
> struct inode *inode = folio->mapping->host;
> + struct fuse_fill_read_data data = {
> + .file = file,
> + };
> int err;
>
> - err = -EIO;
> - if (fuse_is_bad(inode))
> - goto out;
> -
> - err = fuse_do_readfolio(file, folio, 0, folio_size(folio));
> - if (!err)
> - folio_mark_uptodate(folio);
> + if (fuse_is_bad(inode)) {
> + folio_unlock(folio);
> + return -EIO;
> + }
>
> + err = iomap_read_folio(folio, &fuse_iomap_ops, &fuse_iomap_read_ops, &data);
> fuse_invalidate_atime(inode);
> - out:
> - folio_unlock(folio);
> return err;
> }
>
> @@ -1394,20 +1434,6 @@ static const struct iomap_write_ops fuse_iomap_write_ops = {
> .read_folio_range = fuse_iomap_read_folio_range,
> };
>
> -static int fuse_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> - unsigned int flags, struct iomap *iomap,
> - struct iomap *srcmap)
> -{
> - iomap->type = IOMAP_MAPPED;
> - iomap->length = length;
> - iomap->offset = offset;
> - return 0;
> -}
> -
> -static const struct iomap_ops fuse_iomap_ops = {
> - .iomap_begin = fuse_iomap_begin,
> -};
> -
> static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
> {
> struct file *file = iocb->ki_filp;
> --
> 2.47.3
>
>
