Commit 9ea0e45b authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Theodore Ts'o
Browse files

ext4: Use a folio in ext4_page_mkwrite() 



Convert to the folio API, saving a few calls to compound_head().

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20230324180129.1220691-26-willy@infradead.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 86b38c27

fs/ext4/inode.c

+20 −22
Original line number Diff line number Diff line
@@ -6075,7 +6075,7 @@ static int ext4_bh_unmapped(handle_t *handle, struct inode *inode, 
vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)

{

	struct vm_area_struct *vma = vmf->vma;

	struct page *page = vmf->page;

	struct folio *folio = page_folio(vmf->page);

	loff_t size;

	unsigned long len;

	int err;
@@ -6119,19 +6119,18 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) 
		goto out_ret;

	}



	lock_page(page);

	folio_lock(folio);

	size = i_size_read(inode);

	/* Page got truncated from under us? */

	if (page->mapping != mapping || page_offset(page) > size) {

		unlock_page(page);

	if (folio->mapping != mapping || folio_pos(folio) > size) {

		folio_unlock(folio);

		ret = VM_FAULT_NOPAGE;

		goto out;

	}



	if (page->index == size >> PAGE_SHIFT)

		len = size & ~PAGE_MASK;

	else

		len = PAGE_SIZE;

	len = folio_size(folio);

	if (folio_pos(folio) + len > size)

		len = size - folio_pos(folio);

	/*

	 * Return if we have all the buffers mapped. This avoids the need to do

	 * journal_start/journal_stop which can block and take a long time
@@ -6139,17 +6138,17 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) 
	 * This cannot be done for data journalling, as we have to add the

	 * inode to the transaction's list to writeprotect pages on commit.

	 */

	if (page_has_buffers(page)) {

		if (!ext4_walk_page_buffers(NULL, inode, page_buffers(page),

	if (folio_buffers(folio)) {

		if (!ext4_walk_page_buffers(NULL, inode, folio_buffers(folio),

					    0, len, NULL,

					    ext4_bh_unmapped)) {

			/* Wait so that we don't change page under IO */

			wait_for_stable_page(page);

			folio_wait_stable(folio);

			ret = VM_FAULT_LOCKED;

			goto out;

		}

	}

	unlock_page(page);

	folio_unlock(folio);

	/* OK, we need to fill the hole... */

	if (ext4_should_dioread_nolock(inode))

		get_block = ext4_get_block_unwritten;
@@ -6170,26 +6169,25 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) 
	if (!ext4_should_journal_data(inode)) {

		err = block_page_mkwrite(vma, vmf, get_block);

	} else {

		lock_page(page);

		folio_lock(folio);

		size = i_size_read(inode);

		/* Page got truncated from under us? */

		if (page->mapping != mapping || page_offset(page) > size) {

		if (folio->mapping != mapping || folio_pos(folio) > size) {

			ret = VM_FAULT_NOPAGE;

			goto out_error;

		}



		if (page->index == size >> PAGE_SHIFT)

			len = size & ~PAGE_MASK;

		else

			len = PAGE_SIZE;

		len = folio_size(folio);

		if (folio_pos(folio) + len > size)

			len = size - folio_pos(folio);



		err = __block_write_begin(page, 0, len, ext4_get_block);

		err = __block_write_begin(&folio->page, 0, len, ext4_get_block);

		if (!err) {

			ret = VM_FAULT_SIGBUS;

			if (ext4_journal_page_buffers(handle, page, len))

			if (ext4_journal_page_buffers(handle, &folio->page, len))

				goto out_error;

		} else {

			unlock_page(page);

			folio_unlock(folio);

		}

	}

	ext4_journal_stop(handle);
@@ -6202,7 +6200,7 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) 
	sb_end_pagefault(inode->i_sb);

	return ret;

out_error:

	unlock_page(page);

	folio_unlock(folio);

	ext4_journal_stop(handle);

	goto out;

}