1 files changed, 24 insertions, 29 deletions

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 3e9393ca39eb..9cd41083e991 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -61,7 +61,7 @@ static int ocfs2_fault(struct vm_area_struct *area, struct vm_fault *vmf)
 static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
                                 struct page *page)
 {
-        int ret;
+        int ret = VM_FAULT_NOPAGE;
         struct inode *inode = file->f_path.dentry->d_inode;
         struct address_space *mapping = inode->i_mapping;
         loff_t pos = page_offset(page);
@@ -71,32 +71,25 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
         void *fsdata;
         loff_t size = i_size_read(inode);
 
-        /*
-         * Another node might have truncated while we were waiting on
-         * cluster locks.
-         * We don't check size == 0 before the shift. This is borrowed
-         * from do_generic_file_read.
-         */
         last_index = (size - 1) >> PAGE_CACHE_SHIFT;
-        if (unlikely(!size || page->index > last_index)) {
-                ret = -EINVAL;
-                goto out;
-        }
 
         /*
-         * The i_size check above doesn't catch the case where nodes
-         * truncated and then re-extended the file. We'll re-check the
-         * page mapping after taking the page lock inside of
-         * ocfs2_write_begin_nolock().
+         * There are cases that lead to the page no longer bebongs to the
+         * mapping.
+         * 1) pagecache truncates locally due to memory pressure.
+         * 2) pagecache truncates when another is taking EX lock against 
+         * inode lock. see ocfs2_data_convert_worker.
+         * 
+         * The i_size check doesn't catch the case where nodes truncated and
+         * then re-extended the file. We'll re-check the page mapping after
+         * taking the page lock inside of ocfs2_write_begin_nolock().
+         *
+         * Let VM retry with these cases.
          */
-        if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
-                /*
-                 * the page has been umapped in ocfs2_data_downconvert_worker.
-                 * So return 0 here and let VFS retry.
-                 */
-                ret = 0;
+        if ((page->mapping != inode->i_mapping) ||
+            (!PageUptodate(page)) ||
+            (page_offset(page) >= size))
                 goto out;
-        }
 
         /*
          * Call ocfs2_write_begin() and ocfs2_write_end() to take
@@ -116,17 +109,21 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
         if (ret) {
                 if (ret != -ENOSPC)
                         mlog_errno(ret);
+                if (ret == -ENOMEM)
+                        ret = VM_FAULT_OOM;
+                else
+                        ret = VM_FAULT_SIGBUS;
                 goto out;
         }
 
-        ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
-                                     fsdata);
-        if (ret < 0) {
-                mlog_errno(ret);
+        if (!locked_page) {
+                ret = VM_FAULT_NOPAGE;
                 goto out;
         }
+        ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
+                                     fsdata);
         BUG_ON(ret != len);
-        ret = 0;
+        ret = VM_FAULT_LOCKED;
 out:
         return ret;
 }
@@ -168,8 +165,6 @@ static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 out:
         ocfs2_unblock_signals(&oldset);
-        if (ret)
-                ret = VM_FAULT_SIGBUS;
         return ret;
 }