diff mbox series

[V2,05/13] fs/mpage.c: Integrate read callbacks

Message ID 20190428043121.30925-6-chandan@linux.ibm.com (mailing list archive)
State Superseded
Headers show
Series Consolidate FS read I/O callbacks code | expand

Commit Message

Chandan Rajendra April 28, 2019, 4:31 a.m. UTC
This commit adds code to make do_mpage_readpage() to be "read
callbacks" aware i.e. for files requiring decryption/verification,
do_mpage_readpage() now allocates a context structure and assigns the
corresponding pointer to bio->bi_private. At endio time, a non-zero
bio->bi_private indicates that after the read operation is performed, the
bio's payload needs to be processed further before handing over the data
to user space.

The context structure is used for tracking the state machine associated
with post read processing.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/mpage.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/fs/mpage.c b/fs/mpage.c
index 3f19da75178b..e342b859ee44 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -30,6 +30,10 @@ 
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
 #include <linux/cleancache.h>
+#include <linux/fsverity.h>
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+#include <linux/read_callbacks.h>
+#endif
 #include "internal.h"
 
 /*
@@ -50,6 +54,20 @@  static void mpage_end_io(struct bio *bio)
 	int i;
 	struct bvec_iter_all iter_all;
 
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+	if (!bio->bi_status && bio->bi_private) {
+		struct read_callbacks_ctx *ctx;
+
+		ctx = bio->bi_private;
+
+		read_callbacks(ctx);
+		return;
+	}
+
+	if (bio->bi_private)
+		put_read_callbacks_ctx((struct read_callbacks_ctx *)(bio->bi_private));
+#endif
+
 	bio_for_each_segment_all(bv, bio, i, iter_all) {
 		struct page *page = bv->bv_page;
 		page_endio(page, bio_op(bio),
@@ -189,7 +207,13 @@  static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 
 	block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
 	last_block = block_in_file + args->nr_pages * blocks_per_page;
-	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
+#ifdef CONFIG_FS_VERITY
+	if (IS_VERITY(inode) && inode->i_sb->s_vop->readpage_limit)
+		last_block_in_file = inode->i_sb->s_vop->readpage_limit(inode);
+	else
+#endif
+		last_block_in_file = (i_size_read(inode) + blocksize - 1)
+			>> blkbits;
 	if (last_block > last_block_in_file)
 		last_block = last_block_in_file;
 	page_block = 0;
@@ -277,6 +301,14 @@  static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	if (first_hole != blocks_per_page) {
 		zero_user_segment(page, first_hole << blkbits, PAGE_SIZE);
 		if (first_hole == 0) {
+#ifdef CONFIG_FS_VERITY
+			if (IS_VERITY(inode)) {
+				if (!fsverity_check_hole(inode, page)) {
+					SetPageError(page);
+					goto confused;
+				}
+			}
+#endif
 			SetPageUptodate(page);
 			unlock_page(page);
 			goto out;
@@ -299,7 +331,11 @@  static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 
 alloc_new:
 	if (args->bio == NULL) {
-		if (first_hole == blocks_per_page) {
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+		struct read_callbacks_ctx *ctx;
+#endif
+		if (first_hole == blocks_per_page
+			&& !(IS_ENCRYPTED(inode) || IS_VERITY(inode))) {
 			if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
 								page))
 				goto out;
@@ -310,6 +346,15 @@  static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 					gfp);
 		if (args->bio == NULL)
 			goto confused;
+
+#if defined(CONFIG_FS_ENCRYPTION) || defined(CONFIG_FS_VERITY)
+		ctx = get_read_callbacks_ctx(inode, args->bio, page->index);
+		if (IS_ERR(ctx)) {
+			bio_put(args->bio);
+			args->bio = NULL;
+			goto confused;
+		}
+#endif
 	}
 
 	length = first_hole << blkbits;
@@ -331,7 +376,7 @@  static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 confused:
 	if (args->bio)
 		args->bio = mpage_bio_submit(REQ_OP_READ, op_flags, args->bio);
-	if (!PageUptodate(page))
+	if (!PageUptodate(page) && !PageError(page))
 		block_read_full_page(page, args->get_block);
 	else
 		unlock_page(page);