[PATCHv4 41/43] ext4: make fallocate() operations work with huge pages

[Kirill A. Shutemov]

__ext4_block_zero_page_range() adjusted to calculate starting iblock
correctry for huge pages.

ext4_{collapse,insert}_range() requires page cache invalidation. We need
the invalidation to be aligning to huge page border if huge pages are
possible in page cache.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 fs/ext4/extents.c | 10 ++++++++--
 fs/ext4/inode.c   |  3 +--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c930a0110fb4..16a6bdeac36f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -5511,7 +5511,10 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
 	 * Need to round down offset to be aligned with page size boundary
 	 * for page size > block size.
 	 */
-	ioffset = round_down(offset, PAGE_SIZE);
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+		ioffset = round_down(offset, HPAGE_PMD_SIZE);
+	else
+		ioffset = round_down(offset, PAGE_SIZE);
 	/*
 	 * Write tail of the last page before removed range since it will get
 	 * removed from the page cache below.
@@ -5660,7 +5663,10 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
 	 * Need to round down to align start offset to page size boundary
 	 * for page size > block size.
 	 */
-	ioffset = round_down(offset, PAGE_SIZE);
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+		ioffset = round_down(offset, HPAGE_PMD_SIZE);
+	else
+		ioffset = round_down(offset, PAGE_SIZE);
 	/* Write out all dirty pages */
 	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
 			LLONG_MAX);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d179467f82e7..95b64a7cee67 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3716,7 +3716,6 @@ void ext4_set_aops(struct inode *inode)
 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;
 	unsigned blocksize, pos;
 	ext4_lblk_t iblock;
@@ -3735,7 +3734,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 
 	blocksize = inode->i_sb->s_blocksize;
 
-	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
+	iblock = page->index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
 
 	if (!page_has_buffers(page))
 		create_empty_buffers(page, blocksize, 0);
-- 
2.9.3