From: David Sterba <dsterba@suse.com>
Date: Thu, 13 Jul 2017 16:10:07 +0000 (+0200)
Subject: btrfs: cloned bios must not be iterated by bio_for_each_segment_all
X-Git-Tag: v4.13-rc1~12^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c09abff87f90c81d74b6483837a665f97448a475;p=platform%2Fkernel%2Flinux-exynos.git

btrfs: cloned bios must not be iterated by bio_for_each_segment_all

We've started using cloned bios more in 4.13, there are some specifics
regarding the iteration.  Filipe found [1] that the raid56 iterated a
cloned bio using bio_for_each_segment_all, which is incorrect. The
cloned bios have wrong bi_vcnt and this could lead to silent
corruptions.  This patch adds assertions to all remaining
bio_for_each_segment_all cases.

[1] https://patchwork.kernel.org/patch/9838535/

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index fcd323e..8ba1b86 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -152,6 +152,7 @@ csum_failed:
 		 * we have verified the checksum already, set page
 		 * checked so the end_io handlers know about it
 		 */
+		ASSERT(!bio_flagged(bio, BIO_CLONED));
 		bio_for_each_segment_all(bvec, cb->orig_bio, i)
 			SetPageChecked(bvec->bv_page);
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b675889..075beed 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -964,6 +964,7 @@ static int btree_csum_one_bio(struct bio *bio)
 	struct btrfs_root *root;
 	int i, ret = 0;
 
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i) {
 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 		ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2e6f699..a3122fb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2452,6 +2452,7 @@ static void end_bio_extent_writepage(struct bio *bio)
 	u64 end;
 	int i;
 
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
 		struct inode *inode = page->mapping->host;
@@ -2522,6 +2523,7 @@ static void end_bio_extent_readpage(struct bio *bio)
 	int ret;
 	int i;
 
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
 		struct inode *inode = page->mapping->host;
@@ -3675,6 +3677,7 @@ static void end_bio_extent_buffer_writepage(struct bio *bio)
 	struct extent_buffer *eb;
 	int i, done;
 
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5d3c6ac..529437c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8060,6 +8060,7 @@ static void btrfs_retry_endio_nocsum(struct bio *bio)
 	ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode));
 
 	done->uptodate = 1;
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i)
 		clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
 				 io_tree, done->start, bvec->bv_page,
@@ -8151,6 +8152,7 @@ static void btrfs_retry_endio(struct bio *bio)
 	io_tree = &BTRFS_I(inode)->io_tree;
 	failure_tree = &BTRFS_I(inode)->io_failure_tree;
 
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, i) {
 		ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
 					     bvec->bv_offset, done->start,