[PATCH v5 3/7] iomap: support direct I/O with fscrypt using blk-crypto

[Satya Tangirala <satyat@google.com>]

From: Eric Biggers <ebiggers@google.com>

Set bio crypt contexts on bios by calling into fscrypt when required.
No DUN contiguity checks are done - callers are expected to set up the
iomap correctly to ensure that each bio submitted by iomap will not have
blocks with incontiguous DUNs by calling fscrypt_limit_io_blocks()
appropriately.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
---
 fs/iomap/direct-io.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index ec7b78e6feca..a8785bffdc7c 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/compiler.h>
 #include <linux/fs.h>
+#include <linux/fscrypt.h>
 #include <linux/iomap.h>
 #include <linux/backing-dev.h>
 #include <linux/uio.h>
@@ -183,11 +184,14 @@ static void
 iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
 		unsigned len)
 {
+	struct inode *inode = file_inode(dio->iocb->ki_filp);
 	struct page *page = ZERO_PAGE(0);
 	int flags = REQ_SYNC | REQ_IDLE;
 	struct bio *bio;
 
 	bio = bio_alloc(GFP_KERNEL, 1);
+	fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
+				  GFP_KERNEL);
 	bio_set_dev(bio, iomap->bdev);
 	bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
 	bio->bi_private = dio;
@@ -270,6 +274,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 		}
 
 		bio = bio_alloc(GFP_KERNEL, nr_pages);
+		fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
+					  GFP_KERNEL);
 		bio_set_dev(bio, iomap->bdev);
 		bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
 		bio->bi_write_hint = dio->iocb->ki_hint;
-- 
2.28.0.rc0.142.g3c755180ce-goog