On Thu, Feb 06, 2025 at 04:42:56PM +1100, NeilBrown wrote:
> nfs_sillyrename(struct inode *dir, struct dentry *dentry)
> {
> static unsigned int sillycounter;
> @@ -447,7 +451,8 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
> struct dentry *sdentry;
> struct inode *inode = d_inode(dentry);
> struct rpc_task *task;
> - int error = -EBUSY;
> + struct dentry *base;
> + int error = -EBUSY;
>
> dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
> dentry, d_count(dentry));
> @@ -461,10 +466,11 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
>
> fileid = NFS_FILEID(d_inode(dentry));
>
> + base = d_find_alias(dir);
Huh? That would better be dentry->d_parent and all operations are in
that directory, so you don't even need to grab a reference...
> sdentry = NULL;
> do {
> int slen;
> - dput(sdentry);
> +
> sillycounter++;
> slen = scnprintf(silly, sizeof(silly),
> SILLYNAME_PREFIX "%0*llx%0*x",
> @@ -474,14 +480,19 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
> dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
> dentry, silly);
>
> - sdentry = lookup_one_len(silly, dentry->d_parent, slen);
> - /*
> - * N.B. Better to return EBUSY here ... it could be
> - * dangerous to delete the file while it's in use.
> - */
> - if (IS_ERR(sdentry))
> - goto out;
> - } while (d_inode(sdentry) != NULL); /* need negative lookup */
> + sdentry = lookup_and_lock_one(NULL, silly, slen,
> + base,
> + LOOKUP_CREATE | LOOKUP_EXCL
> + | LOOKUP_RENAME_TARGET
> + | LOOKUP_PARENT_LOCKED);
> + } while (PTR_ERR_OR_ZERO(sdentry) == -EEXIST); /* need negative lookup */
What's wrong with sdentry == ERR_PTR(-EEXIST)?
