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: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 59cbe1b..39672b7 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -551,7 +551,7 @@
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 @@
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 = {