Use negative_errno() to assert errno is positive after a few system calls

This is not particularly intrusive because it happens in simple
utility functions. It helps gcc understand that error codes
are negative.

This gets a rid of most of the remaining warnings.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/basic/btrfs-util.c b/src/basic/btrfs-util.c
index acd48f6954..d07d1df5a8 100644
--- a/src/basic/btrfs-util.c
+++ b/src/basic/btrfs-util.c
@@ -2051,7 +2051,7 @@ int btrfs_subvol_get_parent(int fd, uint64_t subvol_id, uint64_t *ret) {
 
                 args.key.nr_items = 256;
                 if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
-                        return -errno;
+                        return negative_errno();
 
                 if (args.key.nr_items <= 0)
                         break;