1 files changed, 59 insertions, 3 deletions

diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 7ddd42e24f77..8031086db8d5 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -73,10 +73,66 @@ nilfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         return ret;
 }
 
-static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-        if (!(vma->vm_flags & (VM_WRITE | VM_MAYWRITE)))
-                return -EPERM;
+        struct page *page = vmf->page;
+        struct inode *inode = vma->vm_file->f_dentry->d_inode;
+        struct nilfs_transaction_info ti;
+        int ret;
+
+        if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
+                return VM_FAULT_SIGBUS; /* -ENOSPC */
+
+        lock_page(page);
+        if (page->mapping != inode->i_mapping ||
+            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
+                unlock_page(page);
+                return VM_FAULT_NOPAGE; /* make the VM retry the fault */
+        }
+
+        /*
+         * check to see if the page is mapped already (no holes)
+         */
+        if (PageMappedToDisk(page)) {
+                unlock_page(page);
+                goto mapped;
+        }
+        if (page_has_buffers(page)) {
+                struct buffer_head *bh, *head;
+                int fully_mapped = 1;
+
+                bh = head = page_buffers(page);
+                do {
+                        if (!buffer_mapped(bh)) {
+                                fully_mapped = 0;
+                                break;
+                        }
+                } while (bh = bh->b_this_page, bh != head);
+
+                if (fully_mapped) {
+                        SetPageMappedToDisk(page);
+                        unlock_page(page);
+                        goto mapped;
+                }
+        }
+        unlock_page(page);
+
+        /*
+         * fill hole blocks
+         */
+        ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
+        /* never returns -ENOMEM, but may return -ENOSPC */
+        if (unlikely(ret))
+                return VM_FAULT_SIGBUS;
+
+        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
+        if (unlikely(ret)) {
+                nilfs_transaction_abort(inode->i_sb);
+                return ret;
+        }
+        nilfs_transaction_commit(inode->i_sb);
+
+ mapped:
         SetPageChecked(page);
         wait_on_page_writeback(page);
         return 0;