[PATCHv6 19/37] fs: make block_page_mkwrite() aware about huge pages

Kirill A. Shutemov
2017-01-26T11:58:01Z

Adjust check on whether part of the page beyond file size and apply
compound_head() and page_mapping() where appropriate.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
fs/buffer.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index d05524f14846..17167b299d0f 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2544,7 +2544,7 @@ EXPORT_SYMBOL(block_commit_write);
int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
get_block_t get_block)
{
- struct page *page = vmf->page;
+ struct page *page = compound_head(vmf->page);
struct inode *inode = file_inode(vma->vm_file);
unsigned long end;
loff_t size;
@@ -2552,7 +2552,7 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,

lock_page(page);
size = i_size_read(inode);
- if ((page->mapping != inode->i_mapping) ||
+ if ((page_mapping(page) != inode->i_mapping) ||
(page_offset(page) > size)) {
/* We overload EFAULT to mean page got truncated */
ret = -EFAULT;
@@ -2560,10 +2560,10 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
}

/* page is wholly or partially inside EOF */
- if (((page->index + 1) << PAGE_SHIFT) > size)
- end = size & ~PAGE_MASK;
+ if (((page->index + hpage_nr_pages(page)) << PAGE_SHIFT) > size)
+ end = size & ~hpage_mask(page);
else
- end = PAGE_SIZE;
+ end = hpage_size(page);

ret = __block_write_begin(page, 0, end, get_block);
if (!ret)