vfs: fix freeze protection in mnt_want_write_file() for overlayfs (a6795a58) · Commits · 戴 / test

The underlying real file used by overlayfs still contains the overlay path. This results in mnt_want_write_file() calls by the filesystem getting freeze protection on the wrong inode (the overlayfs one instead of the real one). Fix by using file_inode(file)->i_sb instead of file->f_path.mnt->mnt_sb. Reported-by:

Amir Goldstein <amir73il@gmail.com> Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:

Christoph Hellwig <hch@lst.de>

fs/namespace.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -441,10 +441,10 @@ int mnt_want_write_file(struct file *file)
		{
		int ret;

		sb_start_write(file->f_path.mnt->mnt_sb);
		sb_start_write(file_inode(file)->i_sb);
		ret = __mnt_want_write_file(file);
		if (ret)
		sb_end_write(file->f_path.mnt->mnt_sb);
		sb_end_write(file_inode(file)->i_sb);
		return ret;
		}
		EXPORT_SYMBOL_GPL(mnt_want_write_file);
		@@ -486,7 +486,8 @@ void __mnt_drop_write_file(struct file *file)

		void mnt_drop_write_file(struct file *file)
		{
		mnt_drop_write(file->f_path.mnt);
		__mnt_drop_write_file(file);
		sb_end_write(file_inode(file)->i_sb);
		}
		EXPORT_SYMBOL(mnt_drop_write_file);

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