NTFS: Add a set_page_dirty address space operation for ntfs_m[fs]t_aops.

      It is simply set to __set_page_dirty_nobuffers() to make sure that
      running set_page_dirty() on a page containing mft/ntfs records will
      not affect the dirty state of the page buffers.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

fs/ntfs/ChangeLog

@@ -79,6 +79,10 @@ ToDo/Notes:
 	- Load the quota file ($Quota) and check if quota tracking is enabled
 	  and if so, mark the quotas out of date.  This causes windows to
 	  rescan the volume on boot and update all quota entries.
+	- Add a set_page_dirty address space operation for ntfs_m[fs]t_aops.
+	  It is simply set to __set_page_dirty_nobuffers() to make sure that
+	  running set_page_dirty() on a page containing mft/ntfs records will
+	  not affect the dirty state of the page buffers.
 
 2.1.14 - Fix an NFSd caused deadlock reported by several users.
 

fs/ntfs/aops.c

@@ -1841,5 +1841,8 @@ struct address_space_operations ntfs_mst_aops = {
 						   disk request queue. */
 #ifdef NTFS_RW
 	.writepage	= ntfs_writepage,	/* Write dirty page to disk. */
+	.set_page_dirty	= __set_page_dirty_nobuffers,	/* Set the page dirty
+						   without touching the buffers
+						   belonging to the page. */
 #endif /* NTFS_RW */
 };

fs/ntfs/mft.c

@@ -122,6 +122,9 @@ struct address_space_operations ntfs_mft_aops = {
 #ifdef NTFS_RW
 	.writepage	= ntfs_mft_writepage,	/* Write out the dirty mft
 						   records in a page. */
+	.set_page_dirty	= __set_page_dirty_nobuffers,	/* Set the page dirty
+						   without touching the buffers
+						   belonging to the page. */
 #endif /* NTFS_RW */
 };
 
@@ -741,7 +744,6 @@ int write_mft_record_nolock(ntfs_inode *ni, MFT_RECORD *m, int sync)
 	ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
 	BUG_ON(NInoAttr(ni));
 	BUG_ON(!max_bhs);
-	BUG_ON(!page);
 	BUG_ON(!PageLocked(page));
 	/*
 	 * If the ntfs_inode is clean no need to do anything.  If it is dirty,
@@ -916,6 +918,7 @@ static int ntfs_mft_writepage(struct page *page, struct writeback_control *wbc)
 	BOOL is_dirty = FALSE;
 
 	BUG_ON(!PageLocked(page));
+	BUG_ON(PageWriteback(page));
 	BUG_ON(mft_vi != vol->mft_ino);
 	/* The first mft record number in the page. */
 	mft_no = page->index << (PAGE_CACHE_SHIFT - vol->mft_record_size_bits);