@@ -157,6 +157,18 @@ static void __netfs_put_subrequest(struct netfs_read_subrequest *subreq,
netfs_put_read_request(rreq, was_async);
}
+static void netfs_init_iov_iter_bvec(struct netfs_read_subrequest *subreq,
+ struct iov_iter *iter)
+{
+ struct bio_vec *bvec = &subreq->bvec;
+
+ bvec->bv_page = folio_page(subreq->rreq->folio, 0);
+ bvec->bv_offset = subreq->start + subreq->transferred;
+ bvec->bv_len = subreq->len - subreq->transferred;
+
+ iov_iter_bvec(iter, READ, bvec, 1, bvec->bv_len);
+}
+
/*
* Clear the unread part of an I/O request.
*/
@@ -164,9 +176,14 @@ static void netfs_clear_unread(struct netfs_read_subrequest *subreq)
{
struct iov_iter iter;
- iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
+ if (subreq->rreq->type == NETFS_TYPE_CACHE) {
+ iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
+ subreq->start + subreq->transferred,
+ subreq->len - subreq->transferred);
+ } else { /* type == NETFS_TYPE_DEMAND */
+ netfs_init_iov_iter_bvec(subreq, &iter);
+ }
+
iov_iter_zero(iov_iter_count(&iter), &iter);
}
@@ -190,9 +207,13 @@ static void netfs_read_from_cache(struct netfs_read_request *rreq,
struct iov_iter iter;
netfs_stat(&netfs_n_rh_read);
- iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
+ if (subreq->rreq->type == NETFS_TYPE_CACHE) {
+ iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
+ subreq->start + subreq->transferred,
+ subreq->len - subreq->transferred);
+ } else { /* type == NETFS_TYPE_DEMAND */
+ netfs_init_iov_iter_bvec(subreq, &iter);
+ }
cres->ops->read(cres, subreq->start, &iter, read_hole,
netfs_cache_read_terminated, subreq);
@@ -17,6 +17,7 @@
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
+#include <linux/bvec.h>
/*
* Overload PG_private_2 to give us PG_fscache - this is used to indicate that
@@ -146,6 +147,7 @@ struct netfs_read_subrequest {
#define NETFS_SREQ_SHORT_READ 2 /* Set if there was a short read from the cache */
#define NETFS_SREQ_SEEK_DATA_READ 3 /* Set if ->read() should SEEK_DATA first */
#define NETFS_SREQ_NO_PROGRESS 4 /* Set if we didn't manage to read any data */
+ struct bio_vec bvec;
};
enum netfs_read_request_type {
In demand-read case, the input folio of netfs API is may not the page cache inside the address space of the netfs file. Instead it may be just a temporary page used to contain the data. In this case, use bvec based iov_iter. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- fs/netfs/read_helper.c | 33 +++++++++++++++++++++++++++------ include/linux/netfs.h | 2 ++ 2 files changed, 29 insertions(+), 6 deletions(-)