Commit c0347550 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: stop checking for NULL return from btrfs_get_extent() 



At extent_io.c, in the read page and write page code paths, we are testing
if the return value from btrfs_get_extent() can be NULL. However that is
not possible, as btrfs_get_extent() always returns either an error pointer
or a (non-NULL) pointer to an extent map structure.

Everywhere else outside extent_io.c we never check for NULL, we always
treat any returned value as a non-NULL pointer if it does not encode an
error.

So check only for the IS_ERR() case at extent_io.c.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e1f53ed8

fs/btrfs/extent_io.c

+3 −3
Original line number Diff line number Diff line
@@ -3534,7 +3534,7 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset, 
	}



	em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, start, len);

	if (em_cached && !IS_ERR_OR_NULL(em)) {

	if (em_cached && !IS_ERR(em)) {

		BUG_ON(*em_cached);

		refcount_inc(&em->refs);

		*em_cached = em;
@@ -3608,7 +3608,7 @@ int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, 
		}

		em = __get_extent_map(inode, page, pg_offset, cur,

				      end - cur + 1, em_cached);

		if (IS_ERR_OR_NULL(em)) {

		if (IS_ERR(em)) {

			unlock_extent(tree, cur, end);

			end_page_read(page, false, cur, end + 1 - cur);

			break;
@@ -3951,7 +3951,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode, 
		}



		em = btrfs_get_extent(inode, NULL, 0, cur, end - cur + 1);

		if (IS_ERR_OR_NULL(em)) {

		if (IS_ERR(em)) {

			btrfs_page_set_error(fs_info, page, cur, end - cur + 1);

			ret = PTR_ERR_OR_ZERO(em);

			break;