@@ -1262,26 +1262,46 @@ static s64 dax_unshare_iter(struct iomap_iter *iter)
{
struct iomap *iomap = &iter->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
- loff_t pos = iter->pos;
- loff_t length = iomap_length(iter);
+ loff_t copy_pos = iter->pos;
+ u64 copy_len = iomap_length(iter);
+ u32 mod;
int id = 0;
s64 ret = 0;
void *daddr = NULL, *saddr = NULL;
if (!iomap_want_unshare_iter(iter))
- return length;
+ return iomap_length(iter);
+
+ /*
+ * Extend the file range to be aligned to fsblock/pagesize, because
+ * we need to copy entire blocks, not just the byte range specified.
+ * Invalidate the mapping because we're about to CoW.
+ */
+ mod = offset_in_page(copy_pos);
+ if (mod) {
+ copy_len += mod;
+ copy_pos -= mod;
+ }
+
+ mod = offset_in_page(copy_pos + copy_len);
+ if (mod)
+ copy_len += PAGE_SIZE - mod;
+
+ invalidate_inode_pages2_range(iter->inode->i_mapping,
+ copy_pos >> PAGE_SHIFT,
+ (copy_pos + copy_len - 1) >> PAGE_SHIFT);
id = dax_read_lock();
- ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL);
+ ret = dax_iomap_direct_access(iomap, copy_pos, copy_len, &daddr, NULL);
if (ret < 0)
goto out_unlock;
- ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL);
+ ret = dax_iomap_direct_access(srcmap, copy_pos, copy_len, &saddr, NULL);
if (ret < 0)
goto out_unlock;
- if (copy_mc_to_kernel(daddr, saddr, length) == 0)
- ret = length;
+ if (copy_mc_to_kernel(daddr, saddr, copy_len) == 0)
+ ret = iomap_length(iter);
else
ret = -EIO;