Btrfs: Do metadata checksums for reads via a workqueue
Before, metadata checksumming was done by the callers of read_tree_block,
which would set EXTENT_CSUM bits in the extent tree to show that a given
range of pages was already checksummed and didn't need to be verified
again.
But, those bits could go away via try_to_releasepage, and the end
result was bogus checksum failures on pages that never left the cache.
The new code validates checksums when the page is read. It is a little
tricky because metadata blocks can span pages and a single read may
end up going via multiple bios.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index d9f5bc4..9d2991d 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -13,7 +13,6 @@
#define EXTENT_DEFRAG (1 << 6)
#define EXTENT_DEFRAG_DONE (1 << 7)
#define EXTENT_BUFFER_FILLED (1 << 8)
-#define EXTENT_CSUM (1 << 9)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
/*
@@ -218,4 +217,7 @@
void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km);
int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
unsigned long len);
+int release_extent_buffer_tail_pages(struct extent_buffer *eb);
+int extent_range_uptodate(struct extent_io_tree *tree,
+ u64 start, u64 end);
#endif
