Commit b0d236e3 authored Apr 25, 2023 by ruanmeisi Committed by Greg Kroah-Hartman Sep 23, 2023

fuse: nlookup missing decrement in fuse_direntplus_link

commit b8bd342d50cbf606666488488f9fea374aceb2d5 upstream.

During our debugging of glusterfs, we found an Assertion failed error:
inode_lookup >= nlookup, which was caused by the nlookup value in the
kernel being greater than that in the FUSE file system.

The issue was introduced by fuse_direntplus_link, where in the function,
fuse_iget increments nlookup, and if d_splice_alias returns failure,
fuse_direntplus_link returns failure without decrementing nlookup
https://github.com/gluster/glusterfs/pull/4081



Signed-off-by: ruanmeisi <ruan.meisi@zte.com.cn>
Fixes: 0b05b183 ("fuse: implement NFS-like readdirplus support")
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0e918d7c

fs/fuse/readdir.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -238,9 +238,17 @@ static int fuse_direntplus_link(struct file *file,
		dput(dentry);
		dentry = alias;
		}
		if (IS_ERR(dentry))
		if (IS_ERR(dentry)) {
		if (!IS_ERR(inode)) {
		struct fuse_inode *fi = get_fuse_inode(inode);

		spin_lock(&fi->lock);
		fi->nlookup--;
		spin_unlock(&fi->lock);
		}
		return PTR_ERR(dentry);
		}
		}
		if (fc->readdirplus_auto)
		set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
		fuse_change_entry_timeout(dentry, o);