Re: [PATCH 1/7] fuse: check directory aliasing in mkdir

From: Trond Myklebust
Date: Mon Nov 28 2005 - 14:56:55 EST


On Mon, 2005-11-28 at 20:43 +0100, Miklos Szeredi wrote:
> Check the created directory inode for aliases in the mkdir() method.


Can't you use d_add_unique() here?

Cheers,
Trond

> Signed-off-by: Miklos Szeredi <miklos@xxxxxxxxxx>
>
> ---
> Index: linux/fs/fuse/dir.c
> ===================================================================
> --- linux.orig/fs/fuse/dir.c 2005-11-28 14:01:08.000000000 +0100
> +++ linux/fs/fuse/dir.c 2005-11-28 14:01:52.000000000 +0100
> @@ -74,6 +74,19 @@ static int fuse_dentry_revalidate(struct
> return 1;
> }
>
> +static int dir_alias(struct inode *inode)
> +{
> + if (S_ISDIR(inode->i_mode)) {
> + /* Don't allow creating an alias to a directory */
> + struct dentry *alias = d_find_alias(inode);
> + if (alias) {
> + dput(alias);
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> static struct dentry_operations fuse_dentry_operations = {
> .d_revalidate = fuse_dentry_revalidate,
> };
> @@ -263,7 +276,7 @@ static int create_new_entry(struct fuse_
> fuse_put_request(fc, req);
>
> /* Don't allow userspace to do really stupid things... */
> - if ((inode->i_mode ^ mode) & S_IFMT) {
> + if (((inode->i_mode ^ mode) & S_IFMT) || dir_alias(inode)) {
> iput(inode);
> return -EIO;
> }
> @@ -874,14 +887,9 @@ static struct dentry *fuse_lookup(struct
> err = fuse_lookup_iget(dir, entry, &inode);
> if (err)
> return ERR_PTR(err);
> - if (inode && S_ISDIR(inode->i_mode)) {
> - /* Don't allow creating an alias to a directory */
> - struct dentry *alias = d_find_alias(inode);
> - if (alias) {
> - dput(alias);
> - iput(inode);
> - return ERR_PTR(-EIO);
> - }
> + if (inode && dir_alias(inode)) {
> + iput(inode);
> + return ERR_PTR(-EIO);
> }
> d_add(entry, inode);
> return NULL;
> -
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