[PATCH v5 10/39] fs: Make page_mkwrite_check_truncate thp-aware

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

If the page is compound, check the last index in the page and return
the appropriate size.  Change the return type to ssize_t in case we ever
support pages larger than 2GB.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 include/linux/pagemap.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 53a914105591..612f6f090d0f 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -828,22 +828,22 @@ static inline unsigned long dir_pages(struct inode *inode)
  * @page: the page to check
  * @inode: the inode to check the page against
  *
- * Returns the number of bytes in the page up to EOF,
+ * Return: The number of bytes in the page up to EOF,
  * or -EFAULT if the page was truncated.
  */
-static inline int page_mkwrite_check_truncate(struct page *page,
+static inline ssize_t page_mkwrite_check_truncate(struct page *page,
                                              struct inode *inode)
 {
        loff_t size = i_size_read(inode);
        pgoff_t index = size >> PAGE_SHIFT;
-       int offset = offset_in_page(size);
+       unsigned long offset = offset_in_thp(page, size);
 
        if (page->mapping != inode->i_mapping)
                return -EFAULT;
 
        /* page is wholly inside EOF */
-       if (page->index < index)
-               return PAGE_SIZE;
+       if (page->index + hpage_nr_pages(page) - 1 < index)
+               return thp_size(page);
        /* page is wholly past EOF */
        if (page->index > index || !offset)
                return -EFAULT;
-- 
2.26.2