libfs: Convert simple_write_begin and simple_write_end to use a folio

Commit Message

Matthew Wilcox Aug. 21, 2023, 2:13 p.m. UTC

Remove a number of implicit calls to compound_head() and various calls
to compatibility functions.  This is not sufficient to enable support
for large folios; generic_perform_write() must be converted first.

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
---
 fs/libfs.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

Comments

Christian Brauner Aug. 21, 2023, 3:25 p.m. UTC | #1

On Mon, 21 Aug 2023 15:13:22 +0100, Matthew Wilcox (Oracle) wrote:
> Remove a number of implicit calls to compound_head() and various calls
> to compatibility functions.  This is not sufficient to enable support
> for large folios; generic_perform_write() must be converted first.
> 
> 

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] libfs: Convert simple_write_begin and simple_write_end to use a folio
      https://git.kernel.org/vfs/vfs/c/22697cef47b7

Patch

diff --git a/fs/libfs.c b/fs/libfs.c
index dcdcc292bf2b..da78eb64831e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -815,21 +815,20 @@  int simple_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len,
 			struct page **pagep, void **fsdata)
 {
-	struct page *page;
-	pgoff_t index;
+	struct folio *folio;
 
-	index = pos >> PAGE_SHIFT;
+	folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, FGP_WRITEBEGIN,
+			mapping_gfp_mask(mapping));
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
 
-	page = grab_cache_page_write_begin(mapping, index);
-	if (!page)
-		return -ENOMEM;
-
-	*pagep = page;
+	*pagep = &folio->page;
 
-	if (!PageUptodate(page) && (len != PAGE_SIZE)) {
-		unsigned from = pos & (PAGE_SIZE - 1);
+	if (!folio_test_uptodate(folio) && (len != folio_size(folio))) {
+		size_t from = offset_in_folio(folio, pos);
 
-		zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
+		folio_zero_segments(folio, 0, from,
+				from + len, folio_size(folio));
 	}
 	return 0;
 }
@@ -861,17 +860,18 @@  static int simple_write_end(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned copied,
 			struct page *page, void *fsdata)
 {
-	struct inode *inode = page->mapping->host;
+	struct folio *folio = page_folio(page);
+	struct inode *inode = folio->mapping->host;
 	loff_t last_pos = pos + copied;
 
-	/* zero the stale part of the page if we did a short copy */
-	if (!PageUptodate(page)) {
+	/* zero the stale part of the folio if we did a short copy */
+	if (!folio_test_uptodate(folio)) {
 		if (copied < len) {
-			unsigned from = pos & (PAGE_SIZE - 1);
+			size_t from = offset_in_folio(folio, pos);
 
-			zero_user(page, from + copied, len - copied);
+			folio_zero_range(folio, from + copied, len - copied);
 		}
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	}
 	/*
 	 * No need to use i_size_read() here, the i_size
@@ -880,9 +880,9 @@  static int simple_write_end(struct file *file, struct address_space *mapping,
 	if (last_pos > inode->i_size)
 		i_size_write(inode, last_pos);
 
-	set_page_dirty(page);
-	unlock_page(page);
-	put_page(page);
+	folio_mark_dirty(folio);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return copied;
 }