nfsd: Fix error cleanup path in nfsd_rename()

Linux kernel 安全漏洞

nfsd: 修正nfsd_rename()函数中的错误清理路径

In the Linux kernel, the following vulnerability has been resolved: nfsd: Fix error cleanup path in nfsd_rename() Commit a8b0026847b8 ("rename(): avoid a deadlock in the case of parents having no common ancestor") added an error bail out path. However this path does not drop the remount protection that has been acquired. Fix the cleanup path to properly drop the remount protection.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于nfsd_rename函数错误清理路径。

在Linux内核中，已解决以下漏洞： nfsd：修复nfsd_rename()中的错误清理路径 提交a8b0026847b8（"rename()：避免在父级没有共同祖先的情况下出现死锁"）添加了一个错误退出路径。然而，这个路径并未释放已获取的重新挂载保护。修复清理路径以正确释放重新挂载保护。