Btrfs-progs: fsck: handle case that we can not lookup extent info

Previously, --init-extent-tree works just because btrfs_lookup_extent_info()
blindly return 0, and this make it work if there are not any *FULL BACKREF*
mode in broken filesystem.

It is just a coincidence that --init-extent-tree option works, let's
do it in the right way firstly.

For now, we have not supported to rebuild extent tree if there are
any *FULL BACKREF* mode which means if there are snapshots with broken
filesystem, avoid using --init-extent-tree option now.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/cmds-check.c b/cmds-check.c
index ae611d1..d1cafe1 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -52,6 +52,7 @@ static LIST_HEAD(duplicate_extents);
 static LIST_HEAD(delete_items);
 static int repair = 0;
 static int no_holes = 0;
+static int init_extent_tree = 0;
 
 struct extent_backref {
        struct list_head list;
@@ -3915,11 +3916,19 @@ static int run_next_block(struct btrfs_trans_handle *trans,
 
        nritems = btrfs_header_nritems(buf);
 
-       ret = btrfs_lookup_extent_info(NULL, root, bytenr,
+       /*
+        * FIXME, this only works only if we don't have any full
+        * backref mode.
+        */
+       if (!init_extent_tree) {
+               ret = btrfs_lookup_extent_info(NULL, root, bytenr,
                                       btrfs_header_level(buf), 1, NULL,
                                       &flags);
-       if (ret < 0)
-               flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+               if (ret < 0)
+                       flags = 0;
+       } else {
+               flags = 0;
+       }
 
        if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
                parent = bytenr;
@@ -5102,12 +5111,20 @@ static int fixup_extent_refs(struct btrfs_trans_handle *trans,
        int allocated = 0;
        u64 flags = 0;
 
-       /* remember our flags for recreating the extent */
-       ret = btrfs_lookup_extent_info(NULL, info->extent_root, rec->start,
-                                      rec->max_size, rec->metadata, NULL,
-                                      &flags);
-       if (ret < 0)
-               flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+       /*
+        * remember our flags for recreating the extent.
+        * FIXME, if we have cleared extent tree, we can not
+        * lookup extent info in extent tree.
+        */
+       if (!init_extent_tree) {
+               ret = btrfs_lookup_extent_info(NULL, info->extent_root,
+                                       rec->start, rec->max_size,
+                                       rec->metadata, NULL, &flags);
+               if (ret < 0)
+                       flags = 0;
+       } else {
+               flags = 0;
+       }
 
        path = btrfs_alloc_path();
        if (!path)
@@ -6438,7 +6455,6 @@ int cmd_check(int argc, char **argv)
        u64 num;
        int option_index = 0;
        int init_csum_tree = 0;
-       int init_extent_tree = 0;
        enum btrfs_open_ctree_flags ctree_flags =
                OPEN_CTREE_PARTIAL | OPEN_CTREE_EXCLUSIVE;
 

diff --git a/extent-tree.c b/extent-tree.c
index 7860d1d..7979457 100644 (file)
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -1560,7 +1560,7 @@ again:
                *flags = extent_flags;
 out:
        btrfs_free_path(path);
-       return 0;
+       return ret;
 }
 
 int btrfs_set_block_flags(struct btrfs_trans_handle *trans,