btrfs-progs: convert: Fix a regression that ext2_save/image is not readonly

The new convert treats the convert image as a normal file, without any
special flags and permissions.

This is different from original code:
1) Permission changed from 0400 to 0600
2) Inode lacks READONLY flag

This makes we can read-write mount the ext2 image and cause rollback
failure.

Follow old code behavior, use 0400 permission and add back READONLY
flag to fix it.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/btrfs-convert.c b/btrfs-convert.c
index b18de59..a8852d6 100644 (file)
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -1527,8 +1527,12 @@ static int create_image(struct btrfs_root *root,
        struct cache_tree used_tmp;
        u64 cur;
        u64 ino;
+       u64 flags = BTRFS_INODE_READONLY;
        int ret;
 
+       if (!datacsum)
+               flags |= BTRFS_INODE_NODATASUM;
+
        trans = btrfs_start_transaction(root, 1);
        if (!trans)
                return -ENOMEM;
@@ -1539,7 +1543,10 @@ static int create_image(struct btrfs_root *root,
                                       &ino);
        if (ret < 0)
                goto out;
-       ret = btrfs_new_inode(trans, root, ino, 0600 | S_IFREG);
+       ret = btrfs_new_inode(trans, root, ino, 0400 | S_IFREG);
+       if (ret < 0)
+               goto out;
+       ret = btrfs_change_inode_flags(trans, root, ino, flags);
        if (ret < 0)
                goto out;
        ret = btrfs_add_link(trans, root, ino, BTRFS_FIRST_FREE_OBJECTID, name,

diff --git a/ctree.h b/ctree.h
index dda72d0..b9fb732 100644 (file)
--- a/ctree.h
+++ b/ctree.h
@@ -2578,6 +2578,8 @@ int check_dir_conflict(struct btrfs_root *root, char *name, int namelen,
                u64 dir, u64 index);
 int btrfs_new_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                u64 ino, u32 mode);
+int btrfs_change_inode_flags(struct btrfs_trans_handle *trans,
+                            struct btrfs_root *root, u64 ino, u64 flags);
 int btrfs_add_link(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   u64 ino, u64 parent_ino, char *name, int namelen,
                   u8 type, u64 *index, int add_backref);

diff --git a/inode.c b/inode.c
index ed6d529..991b8dd 100644 (file)
--- a/inode.c
+++ b/inode.c
@@ -472,6 +472,42 @@ int btrfs_new_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 }
 
 /*
+ * Change inode flags to given value
+ */
+int btrfs_change_inode_flags(struct btrfs_trans_handle *trans,
+                            struct btrfs_root *root, u64 ino, u64 flags)
+{
+       struct btrfs_inode_item *item;
+       struct btrfs_path *path;
+       struct btrfs_key key;
+       int ret;
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       key.objectid = ino;
+       key.type = BTRFS_INODE_ITEM_KEY;
+       key.offset = 0;
+
+       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       if (ret > 0) {
+               ret = -ENOENT;
+               goto out;
+       }
+       if (ret < 0)
+               goto out;
+
+       item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+                             struct btrfs_inode_item);
+       btrfs_set_inode_flags(path->nodes[0], item, flags);
+       btrfs_mark_buffer_dirty(path->nodes[0]);
+out:
+       btrfs_free_path(path);
+       return ret;
+}
+
+/*
  * Make a dir under the parent inode 'parent_ino' with 'name'
  * and 'mode', The owner will be root/root.
  */