btrfs-progs: check: enhance return values of walk_down_tree_v2

In lowmem mode, 'walk_down_tree_v2' returns negative values wheather
the error is fatal or not. It causes the loop where 'walk_down_tree_v2'
is to break even the error is tolerated and then subsequent nodes process
will be skipped.

Fix it by redefining meanings of values 'walk_down_tree_v2' returns.
Do a similar fix for 'process_one_leaf_v2'.

Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-check.c b/cmds-check.c
index c391453..5cc8469 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1868,6 +1868,11 @@ static int update_nodes_refs(struct btrfs_root *root, u64 bytenr,
 static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path,
                            unsigned int ext_ref);
 
+/*
+ * Returns >0  Found error, not fatal, should continue
+ * Returns <0  Fatal error, must exit the whole check
+ * Returns 0   No errors found
+ */
 static int process_one_leaf_v2(struct btrfs_root *root, struct btrfs_path *path,
                               struct node_refs *nrefs, int *level, int ext_ref)
 {
@@ -1937,13 +1942,8 @@ again:
        }
 out:
        err &= ~LAST_ITEM;
-       /*
-        * Convert any error bitmap to -EIO, as we should avoid
-        * mixing positive and negative return value to represent
-        * error
-        */
        if (err && !ret)
-               ret = -EIO;
+               ret = err;
        return ret;
 }
 
@@ -2212,6 +2212,11 @@ out:
 static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path,
                            unsigned int ext_ref);
 
+/*
+ * Returns >0  Found error, should continue
+ * Returns <0  Fatal error, must exit the whole check
+ * Returns 0   No errors found
+ */
 static int walk_down_tree_v2(struct btrfs_root *root, struct btrfs_path *path,
                             int *level, struct node_refs *nrefs, int ext_ref)
 {
@@ -5024,8 +5029,9 @@ static int check_fs_root_v2(struct btrfs_root *root, unsigned int ext_ref)
        struct btrfs_path path;
        struct node_refs nrefs;
        struct btrfs_root_item *root_item = &root->root_item;
-       int ret, wret;
+       int ret;
        int level;
+       int err = 0;
 
        /*
         * We need to manually check the first inode item(256)
@@ -5059,17 +5065,21 @@ static int check_fs_root_v2(struct btrfs_root *root, unsigned int ext_ref)
        }
 
        while (1) {
-               wret = walk_down_tree_v2(root, &path, &level, &nrefs, ext_ref);
-               if (wret < 0)
-                       ret = wret;
-               if (wret != 0)
+               ret = walk_down_tree_v2(root, &path, &level, &nrefs, ext_ref);
+               err |= !!ret;
+
+               /* if ret is negative, walk shall stop */
+               if (ret < 0) {
+                       ret = err;
                        break;
+               }
 
-               wret = walk_up_tree_v2(root, &path, &level);
-               if (wret < 0)
-                       ret = wret;
-               if (wret != 0)
+               ret = walk_up_tree_v2(root, &path, &level);
+               if (ret != 0) {
+                       /* Normal exit, reset ret to err */
+                       ret = err;
                        break;
+               }
        }
 
 out: