Btrfs-progs: allow --init-extent-tree to work when extent tree is borked

Unfortunately you can't run --init-extent-tree if you can't actually read the
extent root.  Fix this by allowing partial starts with no extent root and then
have fsck only check to see if the extent root is uptodate _after_ the check to
see if we are init'ing the extent tree.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.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 dbf48c8..cdcc4ba 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -6008,7 +6008,7 @@ static int reinit_extent_tree(struct btrfs_fs_info *fs_info)
        }
 
        /* Ok we can allocate now, reinit the extent root */
-       ret = btrfs_fsck_reinit_root(trans, fs_info->extent_root, 1);
+       ret = btrfs_fsck_reinit_root(trans, fs_info->extent_root, 0);
        if (ret) {
                fprintf(stderr, "extent root initialization failed\n");
                /*
@@ -6194,20 +6194,23 @@ int cmd_check(int argc, char **argv)
 
        if (!extent_buffer_uptodate(info->tree_root->node) ||
            !extent_buffer_uptodate(info->dev_root->node) ||
-           !extent_buffer_uptodate(info->extent_root->node) ||
            !extent_buffer_uptodate(info->chunk_root->node)) {
                fprintf(stderr, "Critical roots corrupted, unable to fsck the FS\n");
                return -EIO;
        }
 
        root = info->fs_root;
-
        if (init_extent_tree) {
                printf("Creating a new extent tree\n");
                ret = reinit_extent_tree(info);
                if (ret)
                        return ret;
        }
+       if (!extent_buffer_uptodate(info->extent_root->node)) {
+               fprintf(stderr, "Critical roots corrupted, unable to fsck the FS\n");
+               return -EIO;
+       }
+
        fprintf(stderr, "checking extents\n");
        if (init_csum_tree) {
                struct btrfs_trans_handle *trans;

diff --git a/disk-io.c b/disk-io.c
index 0af3898..7ad2cc2 100644 (file)
--- a/disk-io.c
+++ b/disk-io.c
@@ -877,7 +877,17 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
                                  fs_info->extent_root);
        if (ret) {
                printk("Couldn't setup extent tree\n");
-               return -EIO;
+               if (!(flags & OPEN_CTREE_PARTIAL))
+                       return -EIO;
+               /* Need a blank node here just so we don't screw up in the
+                * million of places that assume a root has a valid ->node
+                */
+               fs_info->extent_root->node =
+                       btrfs_find_create_tree_block(fs_info->extent_root, 0,
+                                                    leafsize);
+               if (!fs_info->extent_root->node)
+                       return -ENOMEM;
+               clear_extent_buffer_uptodate(NULL, fs_info->extent_root->node);
        }
        fs_info->extent_root->track_dirty = 1;