btrfs: restore inode creation before xattr setting

According to the tree checker, "all xattrs with a given objectid follow
the inode with that objectid in the tree" is an invariant. This was
broken by the recent change "btrfs: move common inode creation code into
btrfs_create_new_inode()", which moved acl creation and property
inheritance (stored in xattrs) to before inode insertion into the tree.
As a result, under certain timings, the xattrs could be written to the
tree before the inode, causing the tree checker to report violation of
the invariant.

Move property inheritance and acl creation back to their old ordering
after the inode insertion.

Suggested-by: Omar Sandoval <osandov@osandov.com>
Reported-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dbf0599..31ccb82 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6207,43 +6207,6 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
                goto out;
        }
 
-       if (args->subvol) {
-               struct inode *parent;
-
-               /*
-                * Subvolumes inherit properties from their parent subvolume,
-                * not the directory they were created in.
-                */
-               parent = btrfs_iget(fs_info->sb, BTRFS_FIRST_FREE_OBJECTID,
-                                   BTRFS_I(dir)->root);
-               if (IS_ERR(parent)) {
-                       ret = PTR_ERR(parent);
-               } else {
-                       ret = btrfs_inode_inherit_props(trans, inode, parent);
-                       iput(parent);
-               }
-       } else {
-               ret = btrfs_inode_inherit_props(trans, inode, dir);
-       }
-       if (ret) {
-               btrfs_err(fs_info,
-                         "error inheriting props for ino %llu (root %llu): %d",
-                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid,
-                         ret);
-       }
-
-       /*
-        * Subvolumes don't inherit ACLs or get passed to the LSM. This is
-        * probably a bug.
-        */
-       if (!args->subvol) {
-               ret = btrfs_init_inode_security(trans, args);
-               if (ret) {
-                       btrfs_abort_transaction(trans, ret);
-                       goto discard;
-               }
-       }
-
        /*
         * We could have gotten an inode number from somebody who was fsynced
         * and then removed in this same transaction, so let's just set full
@@ -6321,6 +6284,43 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
        btrfs_mark_buffer_dirty(path->nodes[0]);
        btrfs_release_path(path);
 
+       if (args->subvol) {
+               struct inode *parent;
+
+               /*
+                * Subvolumes inherit properties from their parent subvolume,
+                * not the directory they were created in.
+                */
+               parent = btrfs_iget(fs_info->sb, BTRFS_FIRST_FREE_OBJECTID,
+                                   BTRFS_I(dir)->root);
+               if (IS_ERR(parent)) {
+                       ret = PTR_ERR(parent);
+               } else {
+                       ret = btrfs_inode_inherit_props(trans, inode, parent);
+                       iput(parent);
+               }
+       } else {
+               ret = btrfs_inode_inherit_props(trans, inode, dir);
+       }
+       if (ret) {
+               btrfs_err(fs_info,
+                         "error inheriting props for ino %llu (root %llu): %d",
+                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid,
+                         ret);
+       }
+
+       /*
+        * Subvolumes don't inherit ACLs or get passed to the LSM. This is
+        * probably a bug.
+        */
+       if (!args->subvol) {
+               ret = btrfs_init_inode_security(trans, args);
+               if (ret) {
+                       btrfs_abort_transaction(trans, ret);
+                       goto discard;
+               }
+       }
+
        inode_tree_add(inode);
 
        trace_btrfs_inode_new(inode);