Commit bc4866b6 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Don't SIGBUS if nfs_vm_page_mkwrite races with a cache invalidation 



In the case where we lock the page, and then find out that the page has
been thrown out of the page cache, we should just return VM_FAULT_NOPAGE.
This is what block_page_mkwrite() does in these situations.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
parent 955a857e

fs/nfs/file.c

+8 −9
Original line number Diff line number Diff line
@@ -551,7 +551,7 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 
	struct file *filp = vma->vm_file;

	struct dentry *dentry = filp->f_path.dentry;

	unsigned pagelen;

	int ret = -EINVAL;

	int ret = VM_FAULT_NOPAGE;

	struct address_space *mapping;



	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
@@ -567,21 +567,20 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 
	if (mapping != dentry->d_inode->i_mapping)

		goto out_unlock;



	ret = 0;

	pagelen = nfs_page_length(page);

	if (pagelen == 0)

		goto out_unlock;



	ret = nfs_flush_incompatible(filp, page);

	if (ret != 0)

		goto out_unlock;

	ret = VM_FAULT_LOCKED;

	if (nfs_flush_incompatible(filp, page) == 0 &&

	    nfs_updatepage(filp, page, 0, pagelen) == 0)

		goto out;



	ret = nfs_updatepage(filp, page, 0, pagelen);

	ret = VM_FAULT_SIGBUS;

out_unlock:

	if (!ret)

		return VM_FAULT_LOCKED;

	unlock_page(page);

	return VM_FAULT_SIGBUS;

out:

	return ret;

}



static const struct vm_operations_struct nfs_file_vm_ops = {