Cleanup sb->s_fs_info when ovl_fill_super() fails before setting
sb->s_root. The logic is a bit convoluted but tl;dr: If sget_fc() has
succeeded fc->s_fs_info will have been transferred to sb->s_fs_info. So
by the time ->fill_super()/ovl_fill_super() is called fc->s_fs_info is
NULL consequently fs_context->free() won't call ovl_free_fs(). If we
fail before sb->s_root() is set then ->put_super() won't be called which
would call ovl_free_fs(). IOW, if we fail in ->fill_super() before
sb->s_root we have to clean it up.
Amir reported an issue when running xfstests overlay/037 which made me
investigate and detect this.
Fixes: fc0dc3a9b73b ("ovl: port to new mount api")
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
---
I would just fold this into ("ovl: port to new mount api"). The patch
here is mostly so we have a track record of the issue.
Passes both
sudo ./check -overlay overlay/*
sudo ./check -overlay -g overlay/union
I somehow must've missed the earlier failure of overlay/037.
---
fs/overlayfs/super.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index b73b14c52961..9eaff5433dc2 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1949,6 +1949,8 @@ static int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
out_free_oe:
ovl_free_entry(oe);
out_err:
+ ovl_free_fs(ofs);
+ sb->s_fs_info = NULL;
return err;
}
---
base-commit: 2543e5b405156bf506d22db5fc2b04eb7cf236da
change-id: 20230616-fs-overlayfs-mount_api-fix-b1caedfaf8ed
