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Date: Mon, 20 Jul 2020 23:37:35 +0000 From: Satya Tangirala <satyat@...gle.com> To: linux-fscrypt@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net, linux-ext4@...r.kernel.org Cc: linux-xfs@...r.kernel.org, Eric Biggers <ebiggers@...gle.com>, Satya Tangirala <satyat@...gle.com> Subject: [PATCH v4 3/7] iomap: support direct I/O with fscrypt using blk-crypto From: Eric Biggers <ebiggers@...gle.com> Wire up iomap direct I/O with the fscrypt additions for direct I/O. This allows ext4 to support direct I/O on encrypted files when inline encryption is enabled. This change consists of two parts: - Set a bio_crypt_ctx on bios for encrypted files, so that the file contents get encrypted (or decrypted). - Ensure that encryption data unit numbers (DUNs) are contiguous within each bio. Use the new function fscrypt_limit_io_pages() for this, since the iomap code works directly with logical ranges and thus doesn't have a chance to call fscrypt_mergeable_bio() on each page. Note that fscrypt_limit_io_pages() is normally a no-op, as normally the DUNs simply increment along with the logical blocks. But it's needed to handle an edge case in one of the fscrypt IV generation methods. Signed-off-by: Eric Biggers <ebiggers@...gle.com> Co-developed-by: Satya Tangirala <satyat@...gle.com> Signed-off-by: Satya Tangirala <satyat@...gle.com> --- fs/iomap/direct-io.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index ec7b78e6feca..12064daa3e3d 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 +184,16 @@ 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); + + /* encrypted direct I/O is guaranteed to be fs-block aligned */ + WARN_ON_ONCE(fscrypt_needs_contents_encryption(inode)); + bio_set_dev(bio, iomap->bdev); bio->bi_iter.bi_sector = iomap_sector(iomap, pos); bio->bi_private = dio; @@ -253,6 +259,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, ret = nr_pages; goto out; } + nr_pages = fscrypt_limit_io_pages(inode, pos, nr_pages); if (need_zeroout) { /* zero out from the start of the block to the write offset */ @@ -270,6 +277,8 @@ 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; @@ -306,9 +315,10 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, dio->size += n; copied += n; - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); iomap_dio_submit_bio(dio, iomap, bio, pos); pos += n; + nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); + nr_pages = fscrypt_limit_io_pages(inode, pos, nr_pages); } while (nr_pages); /* -- 2.28.0.rc0.105.gf9edc3c819-goog
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