Merge tag 'iomap-6.3-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap updates from Darrick Wong:
 "This is mostly rearranging things to make life easier for gfs2,
  nothing all that mindblowing for this release.

   - Change when the iomap page_done function is called so that we still
     have a locked folio in the success case. This fixes a writeback
     race in gfs2

   - Change when the iomap page_prepare function is called so that gfs2
     can recover from OOM scenarios more gracefully

   - Rename the iomap page_ops to folio_ops, since they operate on
     folios now"

* tag 'iomap-6.3-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: Rename page_ops to folio_ops
  iomap: Rename page_prepare handler to get_folio
  iomap: Add __iomap_get_folio helper
  iomap/gfs2: Get page in page_prepare handler
  iomap: Add iomap_get_folio helper
  iomap: Rename page_done handler to put_folio
  iomap/gfs2: Unlock and put folio in page_done handler
  iomap: Add __iomap_put_folio helper

1 files changed, 60 insertions, 31 deletions

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 356193e44cf0..d3c300563eb8 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -457,6 +457,33 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
 }
 EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
 
+/**
+ * iomap_get_folio - get a folio reference for writing
+ * @iter: iteration structure
+ * @pos: start offset of write
+ *
+ * Returns a locked reference to the folio at @pos, or an error pointer if the
+ * folio could not be obtained.
+ */
+struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos)
+{
+	unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
+	struct folio *folio;
+
+	if (iter->flags & IOMAP_NOWAIT)
+		fgp |= FGP_NOWAIT;
+
+	folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
+			fgp, mapping_gfp_mask(iter->inode->i_mapping));
+	if (folio)
+		return folio;
+
+	if (iter->flags & IOMAP_NOWAIT)
+		return ERR_PTR(-EAGAIN);
+	return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(iomap_get_folio);
+
 bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags)
 {
 	trace_iomap_release_folio(folio->mapping->host, folio_pos(folio),
@@ -575,6 +602,30 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
 	return 0;
 }
 
+static struct folio *__iomap_get_folio(struct iomap_iter *iter, loff_t pos,
+		size_t len)
+{
+	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
+
+	if (folio_ops && folio_ops->get_folio)
+		return folio_ops->get_folio(iter, pos, len);
+	else
+		return iomap_get_folio(iter, pos);
+}
+
+static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret,
+		struct folio *folio)
+{
+	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
+
+	if (folio_ops && folio_ops->put_folio) {
+		folio_ops->put_folio(iter->inode, pos, ret, folio);
+	} else {
+		folio_unlock(folio);
+		folio_put(folio);
+	}
+}
+
 static int iomap_write_begin_inline(const struct iomap_iter *iter,
 		struct folio *folio)
 {
@@ -587,15 +638,11 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter,
 static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 		size_t len, struct folio **foliop)
 {
-	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
+	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
 	const struct iomap *srcmap = iomap_iter_srcmap(iter);
 	struct folio *folio;
-	unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
 	int status = 0;
 
-	if (iter->flags & IOMAP_NOWAIT)
-		fgp |= FGP_NOWAIT;
-
 	BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
 	if (srcmap != &iter->iomap)
 		BUG_ON(pos + len > srcmap->offset + srcmap->length);
@@ -606,18 +653,9 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 	if (!mapping_large_folio_support(iter->inode->i_mapping))
 		len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
 
-	if (page_ops && page_ops->page_prepare) {
-		status = page_ops->page_prepare(iter->inode, pos, len);
-		if (status)
-			return status;
-	}
-
-	folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
-			fgp, mapping_gfp_mask(iter->inode->i_mapping));
-	if (!folio) {
-		status = (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM;
-		goto out_no_page;
-	}
+	folio = __iomap_get_folio(iter, pos, len);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
 
 	/*
 	 * Now we have a locked folio, before we do anything with it we need to
@@ -629,9 +667,9 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 	 * could do the wrong thing here (zero a page range incorrectly or fail
 	 * to zero) and corrupt data.
 	 */
-	if (page_ops && page_ops->iomap_valid) {
-		bool iomap_valid = page_ops->iomap_valid(iter->inode,
-							&iter->iomap);
+	if (folio_ops && folio_ops->iomap_valid) {
+		bool iomap_valid = folio_ops->iomap_valid(iter->inode,
+							 &iter->iomap);
 		if (!iomap_valid) {
 			iter->iomap.flags |= IOMAP_F_STALE;
 			status = 0;
@@ -656,13 +694,9 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
 	return 0;
 
 out_unlock:
-	folio_unlock(folio);
-	folio_put(folio);
+	__iomap_put_folio(iter, pos, 0, folio);
 	iomap_write_failed(iter->inode, pos, len);
 
-out_no_page:
-	if (page_ops && page_ops->page_done)
-		page_ops->page_done(iter->inode, pos, 0, NULL);
 	return status;
 }
 
@@ -712,7 +746,6 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter,
 static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
 		size_t copied, struct folio *folio)
 {
-	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
 	const struct iomap *srcmap = iomap_iter_srcmap(iter);
 	loff_t old_size = iter->inode->i_size;
 	size_t ret;
@@ -735,14 +768,10 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
 		i_size_write(iter->inode, pos + ret);
 		iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
 	}
-	folio_unlock(folio);
+	__iomap_put_folio(iter, pos, ret, folio);
 
 	if (old_size < pos)
 		pagecache_isize_extended(iter->inode, old_size, pos);
-	if (page_ops && page_ops->page_done)
-		page_ops->page_done(iter->inode, pos, ret, &folio->page);
-	folio_put(folio);
-
 	if (ret < len)
 		iomap_write_failed(iter->inode, pos + ret, len - ret);
 	return ret;