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

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Message-Id: <20220322141316.41325-51-jlayton@kernel.org>
Date:   Tue, 22 Mar 2022 10:13:15 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     idryomov@...il.com, xiubli@...hat.com
Cc:     ceph-devel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-fscrypt@...r.kernel.org, linux-kernel@...r.kernel.org,
        lhenriques@...e.de
Subject: [RFC PATCH v11 50/51] ceph: add encryption support to writepage

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@...nel.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