[PATCHv1, RFC 28/33] ext4: handle huge pages in __ext4_block_zero_page_range()

[Kirill A. Shutemov]

As the function handles zeroing range only within one block, the
required changes are trivial, just remove assuption on page size.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 fs/ext4/inode.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 45822097d8c2..3df2cea763ce 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3679,7 +3679,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 		struct address_space *mapping, loff_t from, loff_t length)
 {
 	ext4_fsblk_t index = from >> PAGE_SHIFT;
-	unsigned offset = from & (PAGE_SIZE-1);
+	unsigned offset;
 	unsigned blocksize, pos;
 	ext4_lblk_t iblock;
 	struct inode *inode = mapping->host;
@@ -3692,6 +3692,9 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 	if (!page)
 		return -ENOMEM;
 
+	page = compound_head(page);
+	offset = from & ~hpage_mask(page);
+
 	blocksize = inode->i_sb->s_blocksize;
 
 	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
@@ -3746,7 +3749,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 		if (err)
 			goto unlock;
 	}
-	zero_user(page, offset, length);
+	zero_user(page + offset / PAGE_SIZE, offset % PAGE_SIZE, length);
 	BUFFER_TRACE(bh, "zeroed end of block");
 
 	if (ext4_should_journal_data(inode)) {
-- 
2.8.1