diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 35c83f65475b..8b0507f69c15 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1302,6 +1302,45 @@ ceph_find_incompatible(struct page *page)
 	return NULL;
 }
 
+/**
+ * prep_noread_page - prep a page for writing without reading first
+ * @page: page being prepared
+ * @pos: starting position for the write
+ * @len: length of write
+ *
+ * In some cases, write_begin doesn't need to read at all:
+ * - full page write
+ * - file is currently zero-length
+ * - write that lies in a page that is completely beyond EOF
+ * - write that covers the the page from start to EOF or beyond it
+ *
+ * If any of these criteria are met, then zero out the unwritten parts
+ * of the page and return true. Otherwise, return false.
+ */
+static bool skip_page_read(struct page *page, loff_t pos, size_t len)
+{
+	struct inode *inode = page->mapping->host;
+	loff_t i_size = i_size_read(inode);
+	size_t offset = offset_in_page(pos);
+
+	/* Full page write */
+	if (offset == 0 && len >= PAGE_SIZE)
+		return true;
+
+	/* pos beyond last page in the file */
+	if (pos - offset >= i_size)
+		goto zero_out;
+
+	/* write that covers the whole page from start to EOF or beyond it */
+	if (offset == 0 && (pos + len) >= i_size)
+		goto zero_out;
+
+	return false;
+zero_out:
+	zero_user_segments(page, 0, offset, offset + len, PAGE_SIZE);
+	return true;
+}
+
 /*
  * We are only allowed to write into/dirty the page if the page is
  * clean, or already dirty within the same snap context.
@@ -1315,7 +1354,6 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
 	struct ceph_snap_context *snapc;
 	struct page *page = NULL;
 	pgoff_t index = pos >> PAGE_SHIFT;
-	int pos_in_page = pos & ~PAGE_MASK;
 	int r = 0;
 
 	dout("write_begin file %p inode %p page %p %d~%d\n", file, inode, page, (int)pos, (int)len);
@@ -1350,19 +1388,9 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
 			break;
 		}
 
-		/*
-		 * In some cases we don't need to read at all:
-		 * - full page write
-		 * - write that lies completely beyond EOF
-		 * - write that covers the the page from start to EOF or beyond it
-		 */
-		if ((pos_in_page == 0 && len == PAGE_SIZE) ||
-		    (pos >= i_size_read(inode)) ||
-		    (pos_in_page == 0 && (pos + len) >= i_size_read(inode))) {
-			zero_user_segments(page, 0, pos_in_page,
-					   pos_in_page + len, PAGE_SIZE);
+		/* No need to read in some cases */
+		if (skip_page_read(page, pos, len))
 			break;
-		}
 
 		/*
 		 * We need to read it. If we get back -EINPROGRESS, then the page was