[PATCH 28/42] btrfs: add extra assert for submit_extent_page()

[Qu Wenruo]

There are already bugs exposed in __extent_writepage_io() where due to
wrong alignment and lack of support for subpage, we can pass insane
pg_offset into submit_extent_page().

Add basic size check to ensure the combination of @size and @pg_offset
is sane.

Signed-off-by: Qu Wenruo <w...@suse.com>
---
 fs/btrfs/extent_io.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index be825b73ee43..ae6357a6749e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3261,6 +3261,8 @@ static int submit_extent_page(unsigned int opf,
 
        ASSERT(bio_ret);
 
+       ASSERT(pg_offset < PAGE_SIZE && size <= PAGE_SIZE &&
+              pg_offset + size <= PAGE_SIZE);
        if (*bio_ret) {
                bio = *bio_ret;
                if (force_bio_submit ||
-- 
2.31.1