[PATCH v11 2/5] iomap: support direct I/O with fscrypt using blk-crypto
From: Eric Biggers <ebiggers@kernel.org>
Date: 2022-01-28 23:40:14
Also in:
linux-f2fs-devel, linux-fscrypt, linux-fsdevel, linux-xfs
Subsystem:
filesystems (vfs and infrastructure), filesystems [iomap], the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Eric Biggers <redacted> Encrypted files traditionally haven't supported DIO, due to the need to encrypt/decrypt the data. However, when the encryption is implemented using inline encryption (blk-crypto) instead of the traditional filesystem-layer encryption, it is straightforward to support DIO. Add support for this to the iomap DIO implementation by calling fscrypt_set_bio_crypt_ctx() to set encryption contexts on the bios. Don't check for the rare case where a DUN (crypto data unit number) discontiguity creates a boundary that bios must not cross. Instead, filesystems are expected to handle this in ->iomap_begin() by limiting the length of the mapping so that iomap doesn't have to worry about it. Co-developed-by: Satya Tangirala <redacted> Signed-off-by: Satya Tangirala <redacted> Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Eric Biggers <redacted> --- 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 03ea367df19a4..20325b3926fa3 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/pagemap.h> #include <linux/iomap.h> #include <linux/backing-dev.h>
@@ -179,11 +180,14 @@ static void iomap_dio_bio_end_io(struct bio *bio) static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, 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, iter->iomap.bdev); bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos); bio->bi_private = dio;
@@ -310,6 +314,8 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, } 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;
--
2.35.0