[PATCH v16 57/68] ceph: add fscrypt decryption support to ceph_netfs_issue_op

[xiubli@redhat.com]

From: Jeff Layton <jlayton@kernel.org>

Force the use of sparse reads when the inode is encrypted, and add the
appropriate code to decrypt the extent map after receiving.

Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/addr.c | 64 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 9 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 13d1c24d2f53..8ee7e5451d5f 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>
 
@@ -216,7 +217,8 @@ static bool ceph_netfs_clamp_length(struct netfs_io_subrequest *subreq)
 
 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_io_subrequest *subreq = req->r_priv;
 	struct ceph_osd_req_op *op = &req->r_ops[0];
@@ -230,16 +232,30 @@ static void finish_netfs_read(struct ceph_osd_request *req)
 	     subreq->len, i_size_read(req->r_inode));
 
 	/* no object means success but no data */
-	if (sparse && err >= 0)
-		err = ceph_sparse_ext_map_end(op);
-	else if (err == -ENOENT)
+	if (err == -ENOENT)
 		err = 0;
 	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 (sparse && err > 0)
+			err = ceph_sparse_ext_map_end(op);
+		if (err < subreq->len)
+			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+		if (IS_ENCRYPTED(inode) && err > 0) {
+			err = ceph_fscrypt_decrypt_extents(inode, osd_data->pages,
+					subreq->start, op->extent.sparse_ext,
+					op->extent.sparse_ext_cnt);
+			if (err > subreq->len)
+				err = subreq->len;
+		}
+	}
 
+	if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGES) {
+		ceph_put_page_vector(osd_data->pages,
+				     calc_pages_for(osd_data->alignment,
+					osd_data->length), false);
+	}
 	netfs_subreq_terminated(subreq, err, false);
 	iput(req->r_inode);
 }
@@ -310,7 +326,8 @@ static void ceph_netfs_issue_read(struct netfs_io_subrequest *subreq)
 	struct iov_iter iter;
 	int err = 0;
 	u64 len = subreq->len;
-	bool sparse = ceph_test_mount_opt(fsc, SPARSEREAD);
+	bool sparse = IS_ENCRYPTED(inode) || ceph_test_mount_opt(fsc, SPARSEREAD);
+	u64 off = subreq->start;
 
 	if (ceph_inode_is_shutdown(inode)) {
 		err = -EIO;
@@ -320,7 +337,9 @@ static void ceph_netfs_issue_read(struct netfs_io_subrequest *subreq)
 	if (ceph_has_inline_data(ci) && ceph_netfs_issue_op_inline(subreq))
 		return;
 
-	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, subreq->start, &len,
+	ceph_fscrypt_adjust_off_and_len(inode, &off, &len);
+
+	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, off, &len,
 			0, 1, sparse ? CEPH_OSD_OP_SPARSE_READ : 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);
@@ -337,8 +356,35 @@ static void ceph_netfs_issue_read(struct netfs_io_subrequest *subreq)
 	}
 
 	dout("%s: pos=%llu orig_len=%zu len=%llu\n", __func__, subreq->start, subreq->len, len);
+
 	iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, subreq->start, len);
-	osd_req_op_extent_osd_iter(req, 0, &iter);
+
+	/*
+	 * FIXME: For now, use CEPH_OSD_DATA_TYPE_PAGES instead of _ITER for
+	 * encrypted inodes. We'd need infrastructure that handles an iov_iter
+	 * instead of page arrays, and we don't have that as of yet. Once the
+	 * dust settles on the write helpers and encrypt/decrypt routines for
+	 * netfs, we should be able to rework this.
+	 */
+	if (IS_ENCRYPTED(inode)) {
+		struct page **pages;
+		size_t page_off;
+
+		err = iov_iter_get_pages_alloc2(&iter, &pages, len, &page_off);
+		if (err < 0) {
+			dout("%s: iov_ter_get_pages_alloc returned %d\n", __func__, err);
+			goto out;
+		}
+
+		/* should always give us a page-aligned read */
+		WARN_ON_ONCE(page_off);
+		len = err;
+		err = 0;
+
+		osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
+	} else {
+		osd_req_op_extent_osd_iter(req, 0, &iter);
+	}
 	req->r_callback = finish_netfs_read;
 	req->r_priv = subreq;
 	req->r_inode = inode;
-- 
2.31.1