[PATCHv5 28/36] ext4: make ext4_block_write_begin() aware about huge pages

Kirill A. Shutemov
2016-11-29T11:22:56Z

It simply matches changes to __block_write_begin_int().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
fs/ext4/inode.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d3143dfe9962..21662bcbbbcb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1094,9 +1094,8 @@ int do_journal_get_write_access(handle_t *handle,
static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
get_block_t *get_block)
{
- unsigned from = pos & (PAGE_SIZE - 1);
- unsigned to = from + len;
- struct inode *inode = page->mapping->host;
+ unsigned from, to;
+ struct inode *inode = page_mapping(page)->host;
unsigned block_start, block_end;
sector_t block;
int err = 0;
@@ -1104,10 +1103,14 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
unsigned bbits;
struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
bool decrypt = false;
+ bool uptodate = PageUptodate(page);

+ page = compound_head(page);
+ from = pos & ~hpage_mask(page);
+ to = from + len;
BUG_ON(!PageLocked(page));
- BUG_ON(from > PAGE_SIZE);
- BUG_ON(to > PAGE_SIZE);
+ BUG_ON(from > hpage_size(page));
+ BUG_ON(to > hpage_size(page));
BUG_ON(from > to);

if (!page_has_buffers(page))
@@ -1120,10 +1123,8 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
block++, block_start = block_end, bh = bh->b_this_page) {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
- if (PageUptodate(page)) {
- if (!buffer_uptodate(bh))
- set_buffer_uptodate(bh);
- }
+ if (uptodate && !buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
continue;
}
if (buffer_new(bh))
@@ -1135,19 +1136,25 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
break;
if (buffer_new(bh)) {
clean_bdev_bh_alias(bh);
- if (PageUptodate(page)) {
+ if (uptodate) {
clear_buffer_new(bh);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
continue;
}
- if (block_end > to || block_start < from)
- zero_user_segments(page, to, block_end,
- block_start, from);
+ if (block_end > to || block_start < from) {
+ BUG_ON(to - from > PAGE_SIZE);
+ zero_user_segments(page +
+ block_start / PAGE_SIZE,
+ to % PAGE_SIZE,
+ (block_start % PAGE_SIZE) + blocksize,
+ block_start % PAGE_SIZE,
+ from % PAGE_SIZE);
+ }
continue;
}
}
- if (PageUptodate(page)) {
+ if (uptodate) {
if (!buffer_uptodate(bh))
set_buffer_uptodate(bh);
continue;