NTFS: - Fix creation of buffers in fs/ntfs/mft.c::ntfs_sync_mft_mirror().

        Cannot just call fs/ntfs/aops.c::mark_ntfs_record_dirty() since
        this also marks the page dirty so we create the buffers by hand
        and set them uptodate.
      - Revert the removal of the page uptodate check from
        fs/ntfs/aops.c::mark_ntfs_record_dirty() as it is no longer called
        from fs/ntfs/mft.c::ntfs_sync_mft_mirror().
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

fs/ntfs/ChangeLog

@@ -89,9 +89,6 @@ ToDo/Notes:
 	  and write_mft_record_nolock().  From now on we require that the
 	  complete runlist for the mft mirror is always mapped into memory.
 	- Add creation of buffers to fs/ntfs/mft.c::ntfs_sync_mft_mirror().
-	- Do not check for the page being uptodate in mark_ntfs_record_dirty()
-	  as we now call this after marking the page not uptodate during mft
-	  mirror synchronisation (fs/ntfs/mft.c::ntfs_sync_mft_mirror()).
 	- Improve error handling in fs/ntfs/aops.c::ntfs_{read,write}_block().
 
 2.1.21 - Fix some races and bugs, rewrite mft write code, add mft allocator.

fs/ntfs/aops.c

@@ -819,6 +819,12 @@ static int ntfs_write_mst_block(struct page *page,
 	BUG_ON(!NInoNonResident(ni));
 	BUG_ON(!NInoMstProtected(ni));
 	is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
+	/*
+	 * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
+	 * in its page cache were to be marked dirty.  However this should
+	 * never happen with the current driver and considering we do not
+	 * handle this case here we do want to BUG(), at least for now.
+	 */
 	BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
 			(NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
 	BUG_ON(!max_bhs);
@@ -2282,6 +2288,7 @@ void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
 	struct buffer_head *bh, *head, *buffers_to_free = NULL;
 	unsigned int end, bh_size, bh_ofs;
 
+	BUG_ON(!PageUptodate(page));
 	end = ofs + ni->itype.index.block_size;
 	bh_size = 1 << VFS_I(ni)->i_blkbits;
 	spin_lock(&mapping->private_lock);

fs/ntfs/mft.c

@@ -497,12 +497,20 @@ int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no,
 	kmirr = page_address(page) + page_ofs;
 	/* Copy the mst protected mft record to the mirror. */
 	memcpy(kmirr, m, vol->mft_record_size);
-	/*
-	 * Create buffers if not present and mark the ones belonging to the mft
-	 * mirror record dirty.
-	 */
-	mark_ntfs_record_dirty(page, page_ofs);
-	BUG_ON(!page_has_buffers(page));
+	/* Create uptodate buffers if not present. */
+	if (unlikely(!page_has_buffers(page))) {
+		struct buffer_head *tail;
+
+		bh = head = alloc_page_buffers(page, blocksize, 1);
+		do {
+			set_buffer_uptodate(bh);
+			tail = bh;
+			bh = bh->b_this_page;
+		} while (bh);
+		tail->b_this_page = head;
+		attach_page_buffers(page, head);
+		BUG_ON(!page_has_buffers(page));
+	}
 	bh = head = page_buffers(page);
 	BUG_ON(!bh);
 	rl = NULL;