[PATCH v2] ceph: invalidate pages when doing DIO in encrypted inodes

["Luís Henriques" <lhenriques@suse.de>]

When doing DIO on an encrypted node, we need to invalidate the page cache in
the range being written to, otherwise the cache will include invalid data.

Signed-off-by: Luís Henriques <lhenriques@suse.de>
---
 fs/ceph/file.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Changes since v1:
- Replaced truncate_inode_pages_range() by invalidate_inode_pages2_range
- Call fscache_invalidate with FSCACHE_INVAL_DIO_WRITE if we're doing DIO

Note: I'm not really sure this last change is required, it doesn't really
affect generic/647 result, but seems to be the most correct.

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 5072570c2203..b2743c342305 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1605,7 +1605,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 	if (ret < 0)
 		return ret;
 
-	ceph_fscache_invalidate(inode, false);
+	ceph_fscache_invalidate(inode, (iocb->ki_flags & IOCB_DIRECT));
 	ret = invalidate_inode_pages2_range(inode->i_mapping,
 					    pos >> PAGE_SHIFT,
 					    (pos + count - 1) >> PAGE_SHIFT);
@@ -1895,6 +1895,15 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 		req->r_inode = inode;
 		req->r_mtime = mtime;
 
+		if (IS_ENCRYPTED(inode) && (iocb->ki_flags & IOCB_DIRECT)) {
+			ret = invalidate_inode_pages2_range(
+				inode->i_mapping,
+				write_pos >> PAGE_SHIFT,
+				(write_pos + write_len - 1) >> PAGE_SHIFT);
+			if (ret < 0)
+				dout("invalidate_inode_pages2_range returned %d\n", ret);
+		}
+
 		/* Set up the assertion */
 		if (rmw) {
 			/*