fuse: lock page in mkwrite
Lock the page in fuse_page_mkwrite() to protect against a race with
fuse_writepage() where the page is redirtied before the actual writeback
begins.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 944acc0..6fb9425 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1618,14 +1618,17 @@
static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *page = vmf->page;
- /*
- * Don't use page->mapping as it may become NULL from a
- * concurrent truncate.
- */
- struct inode *inode = vma->vm_file->f_mapping->host;
+ struct inode *inode = file_inode(vma->vm_file);
+
+ file_update_time(vma->vm_file);
+ lock_page(page);
+ if (page->mapping != inode->i_mapping) {
+ unlock_page(page);
+ return VM_FAULT_NOPAGE;
+ }
fuse_wait_on_page_writeback(inode, page->index);
- return 0;
+ return VM_FAULT_LOCKED;
}
static const struct vm_operations_struct fuse_file_vm_ops = {
