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>

4 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index fcd323eceb5b..8ba1b86c9b72 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 b6758892874f..075beedb4352 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 2e6f69908303..a3122fba54e8 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 5d3c6ac960fd..529437c337b4 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,