[RFC,v10,46/48] ceph: add fscrypt decryption support to ceph_netfs_issue_op

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index b3d9459c9bbd..dbc587a41fea 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -18,6 +18,7 @@ 
 #include "mds_client.h"
 #include "cache.h"
 #include "metric.h"
+#include "crypto.h"
 #include <linux/ceph/osd_client.h>
 #include <linux/ceph/striper.h>
 
@@ -200,7 +201,7 @@  static void ceph_netfs_expand_readahead(struct netfs_read_request *rreq)
 	rreq->len = roundup(rreq->len, lo->stripe_unit);
 }
 
-static bool ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
+static size_t __ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
 {
 	struct inode *inode = subreq->rreq->mapping->host;
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
@@ -211,13 +212,18 @@  static bool ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
 	/* Truncate the extent at the end of the current block */
 	ceph_calc_file_object_mapping(&ci->i_layout, subreq->start, subreq->len,
 				      &objno, &objoff, &xlen);
-	subreq->len = min(xlen, fsc->mount_options->rsize);
-	return true;
+	return min(xlen, fsc->mount_options->rsize);
 }
 
+static bool ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
+{
+	subreq->len = __ceph_netfs_clamp_length(subreq);
+	return true;
+}
 static void finish_netfs_read(struct ceph_osd_request *req)
 {
-	struct ceph_fs_client *fsc = ceph_inode_to_client(req->r_inode);
+	struct inode *inode = req->r_inode;
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 	struct ceph_osd_data *osd_data = osd_req_op_extent_osd_data(req, 0);
 	struct netfs_read_subrequest *subreq = req->r_priv;
 	int num_pages;
@@ -235,8 +241,16 @@  static void finish_netfs_read(struct ceph_osd_request *req)
 	else if (err == -EBLOCKLISTED)
 		fsc->blocklisted = true;
 
-	if (err >= 0 && err < subreq->len)
-		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+	if (err >= 0) {
+		if (err < subreq->len)
+			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+		if (IS_ENCRYPTED(inode)) {
+			err = ceph_fscrypt_decrypt_pages(inode, osd_data->pages,
+							 subreq->start, err);
+			if (err > subreq->len)
+				err = subreq->len;
+		}
+	}
 
 	netfs_subreq_terminated(subreq, err, true);
 
@@ -258,8 +272,11 @@  static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
 	size_t page_off;
 	int err = 0;
 	u64 len = subreq->len;
+	u64 off = subreq->start;
+
+	fscrypt_adjust_off_and_len(inode, &off, &len);
 
-	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, subreq->start, &len,
+	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, off, &len,
 			0, 1, CEPH_OSD_OP_READ,
 			CEPH_OSD_FLAG_READ | fsc->client->osdc.client->options->read_from_replica,
 			NULL, ci->i_truncate_seq, ci->i_truncate_size, false);
@@ -270,7 +287,7 @@  static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
 	}
 
 	dout("%s: pos=%llu orig_len=%zu len=%llu\n", __func__, subreq->start, subreq->len, len);
-	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
+	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, off, len);
 	err = iov_iter_get_pages_alloc(&iter, &pages, len, &page_off);
 	if (err < 0) {
 		dout("%s: iov_ter_get_pages_alloc returned %d\n", __func__, err);