Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

[pandora-kernel.git] / fs / ocfs2 / mmap.c

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 3e9393c..9cd4108 100644 (file)
--- 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;
 }