[RFC PATCH v11 50/51] ceph: add encryption support to writepage

[Jeff Layton <jlayton@kernel.org>]

Allow writepage to issue encrypted writes. Extend out the requested size
and offset to cover complete blocks, and then encrypt and write them to
the OSDs.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/addr.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 13a37a568a1d..403e7a960a4e 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -594,10 +594,12 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	loff_t page_off = page_offset(page);
 	int err;
 	loff_t len = thp_size(page);
+	loff_t wlen;
 	struct ceph_writeback_ctl ceph_wbc;
 	struct ceph_osd_client *osdc = &fsc->client->osdc;
 	struct ceph_osd_request *req;
 	bool caching = ceph_is_cache_enabled(inode);
+	struct page *bounce_page = NULL;
 
 	dout("writepage %p idx %lu\n", page, page->index);
 
@@ -628,6 +630,8 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 
 	if (ceph_wbc.i_size < page_off + len)
 		len = ceph_wbc.i_size - page_off;
+	if (IS_ENCRYPTED(inode))
+		wlen = round_up(len, CEPH_FSCRYPT_BLOCK_SIZE);
 
 	dout("writepage %p page %p index %lu on %llu~%llu snapc %p seq %lld\n",
 	     inode, page, page->index, page_off, len, snapc, snapc->seq);
@@ -636,22 +640,37 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 
-	req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1,
-				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc,
-				    ceph_wbc.truncate_seq, ceph_wbc.truncate_size,
-				    true);
+	req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode),
+				    page_off, &wlen, 0, 1, CEPH_OSD_OP_WRITE,
+				    CEPH_OSD_FLAG_WRITE, snapc,
+				    ceph_wbc.truncate_seq,
+				    ceph_wbc.truncate_size, true);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
+	if (wlen < len)
+		len = wlen;
+
 	set_page_writeback(page);
 	if (caching)
 		ceph_set_page_fscache(page);
 	ceph_fscache_write_to_cache(inode, page_off, len, caching);
 
+	if (IS_ENCRYPTED(inode)) {
+		bounce_page = fscrypt_encrypt_pagecache_blocks(page, CEPH_FSCRYPT_BLOCK_SIZE,
+								0, GFP_NOFS);
+		if (IS_ERR(bounce_page)) {
+			err = PTR_ERR(bounce_page);
+			goto out;
+		}
+	}
 	/* it may be a short write due to an object boundary */
 	WARN_ON_ONCE(len > thp_size(page));
-	osd_req_op_extent_osd_data_pages(req, 0, &page, len, 0, false, false);
-	dout("writepage %llu~%llu (%llu bytes)\n", page_off, len, len);
+	osd_req_op_extent_osd_data_pages(req, 0,
+			bounce_page ? &bounce_page : &page, wlen, 0,
+			false, false);
+	dout("writepage %llu~%llu (%llu bytes, %sencrypted)\n",
+	     page_off, len, wlen, IS_ENCRYPTED(inode) ? "" : "not ");
 
 	req->r_mtime = inode->i_mtime;
 	err = ceph_osdc_start_request(osdc, req, true);
@@ -660,7 +679,8 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 
 	ceph_update_write_metrics(&fsc->mdsc->metric, req->r_start_latency,
 				  req->r_end_latency, len, err);
-
+	fscrypt_free_bounce_page(bounce_page);
+out:
 	ceph_osdc_put_request(req);
 	if (err == 0)
 		err = len;
-- 
2.35.1