On Thu 14-09-17 14:47:28, Andreas Grünbacher wrote:

2017-09-14 14:02 GMT+02:00 Jan Kara [off-list ref]:

quoted

On Thu 14-09-17 11:50:47, Andreas Gruenbacher wrote:

quoted

@@ -3422,9 +3422,38 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
      map.m_lblk = first_block;
      map.m_len = last_block - first_block + 1;

-     if (!(flags & IOMAP_WRITE)) {
+     if (flags & IOMAP_REPORT) {
              ret = ext4_map_blocks(NULL, inode, &map, 0);
-     } else {
+             if (ret < 0)
+                     return ret;
+
+             if (ret == 0) {
+                     ext4_lblk_t end = map.m_lblk + map.m_len - 1;
+                     struct extent_status es;
+
+                     ext4_es_find_delayed_extent_range(inode, map.m_lblk, end, &es);
+
+                     if (!es.es_len || es.es_lblk > end) {
+                             /* entire range is a hole */
+                     } else if (es.es_lblk > map.m_lblk) {
+                             /* range starts with a hole */
+                             map.m_len = es.es_lblk - map.m_lblk;
+                     } else {
+                             ext4_lblk_t offs = 0;
+
+                             if (es.es_lblk < map.m_lblk)
+                                     offs = map.m_lblk - es.es_lblk;
+                             map.m_lblk = es.es_lblk + offs;
+                             map.m_pblk = ext4_es_pblock(&es) + offs;
+                             map.m_len = es.es_len - offs;
+                             if (ext4_es_is_unwritten(&es))
+                                     map.m_flags |= EXT4_MAP_UNWRITTEN;

This is not possible. If there is unwritten extent at map->m_lblk, then
ext4_map_blocks() could not have possibly returned 0. So just delete this
condition and set map.m_pblk to 0 since delalloc extent has no physical
position.

quoted

+                             if (ext4_es_is_delayed(&es))
+                                     delalloc = true;

Also ext4_es_is_delayed(&es) is guaranteed to be true since you've looked
it up by ext4_es_find_delayed_extent_range(). So just set delalloc = true
unconditionally.

Since map.m_pblk is never used in the delalloc case, we can leave it
undefined above as well.

Yeah, that's fine by me as well.

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR