[PATCH 0/5] Convert ext4's mballoc to use folios

[PATCH 0/5] Convert ext4's mballoc to use folios

[Matthew Wilcox (Oracle)]

These pages are stored in the page cache, so they're really folios.
Convert the whole file from pages to folios.

Matthew Wilcox (Oracle) (5):
  ext4: Convert bd_bitmap_page to bd_bitmap_folio
  ext4: Convert bd_buddy_page to bd_buddy_folio
  ext4: Convert ext4_mb_init_cache() to take a folio
  ext4: Convert ac_bitmap_page to ac_bitmap_folio
  ext4: Convert ac_buddy_page to ac_buddy_folio

 fs/ext4/mballoc.c | 230 +++++++++++++++++++++++-----------------------
 fs/ext4/mballoc.h |   8 +-
 2 files changed, 121 insertions(+), 117 deletions(-)

-- 
2.43.0

[PATCH 1/5] ext4: Convert bd_bitmap_page to bd_bitmap_folio

[Matthew Wilcox (Oracle)]

There is no need to make this a multi-page folio, so leave all the
infrastructure around it in pages.  But since we're locking it, playing
with its refcount and checking whether it's uptodate, it needs to move
to the folio API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ext4/mballoc.c | 98 ++++++++++++++++++++++++-----------------------
 fs/ext4/mballoc.h |  2 +-
 2 files changed, 52 insertions(+), 48 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 12b3f196010b..91c015fda370 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1448,9 +1448,10 @@ static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 	int block, pnum, poff;
 	int blocks_per_page;
 	struct page *page;
+	struct folio *folio;
 
 	e4b->bd_buddy_page = NULL;
-	e4b->bd_bitmap_page = NULL;
+	e4b->bd_bitmap_folio = NULL;
 
 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
 	/*
@@ -1461,12 +1462,13 @@ static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 	block = group * 2;
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
-	page = find_or_create_page(inode->i_mapping, pnum, gfp);
-	if (!page)
-		return -ENOMEM;
-	BUG_ON(page->mapping != inode->i_mapping);
-	e4b->bd_bitmap_page = page;
-	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+	folio = __filemap_get_folio(inode->i_mapping, pnum,
+			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	BUG_ON(folio->mapping != inode->i_mapping);
+	e4b->bd_bitmap_folio = folio;
+	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
 
 	if (blocks_per_page >= 2) {
 		/* buddy and bitmap are on the same page */
@@ -1484,9 +1486,9 @@ static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 
 static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
 {
-	if (e4b->bd_bitmap_page) {
-		unlock_page(e4b->bd_bitmap_page);
-		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_bitmap_folio) {
+		folio_unlock(e4b->bd_bitmap_folio);
+		folio_put(e4b->bd_bitmap_folio);
 	}
 	if (e4b->bd_buddy_page) {
 		unlock_page(e4b->bd_buddy_page);
@@ -1506,6 +1508,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 	struct ext4_group_info *this_grp;
 	struct ext4_buddy e4b;
 	struct page *page;
+	struct folio *folio;
 	int ret = 0;
 
 	might_sleep();
@@ -1532,11 +1535,11 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 		goto err;
 	}
 
-	page = e4b.bd_bitmap_page;
-	ret = ext4_mb_init_cache(page, NULL, gfp);
+	folio = e4b.bd_bitmap_folio;
+	ret = ext4_mb_init_cache(&folio->page, NULL, gfp);
 	if (ret)
 		goto err;
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
@@ -1578,6 +1581,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	int pnum;
 	int poff;
 	struct page *page;
+	struct folio *folio;
 	int ret;
 	struct ext4_group_info *grp;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -1596,7 +1600,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	e4b->bd_sb = sb;
 	e4b->bd_group = group;
 	e4b->bd_buddy_page = NULL;
-	e4b->bd_bitmap_page = NULL;
+	e4b->bd_bitmap_folio = NULL;
 
 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
 		/*
@@ -1617,53 +1621,53 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
 
-	/* we could use find_or_create_page(), but it locks page
-	 * what we'd like to avoid in fast path ... */
-	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
-	if (page == NULL || !PageUptodate(page)) {
-		if (page)
+	/* Avoid locking the folio in the fast path ... */
+	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+		if (!IS_ERR(folio))
 			/*
-			 * drop the page reference and try
-			 * to get the page with lock. If we
+			 * drop the folio reference and try
+			 * to get the folio with lock. If we
 			 * are not uptodate that implies
-			 * somebody just created the page but
-			 * is yet to initialize the same. So
+			 * somebody just created the folio but
+			 * is yet to initialize it. So
 			 * wait for it to initialize.
 			 */
-			put_page(page);
-		page = find_or_create_page(inode->i_mapping, pnum, gfp);
-		if (page) {
-			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
-	"ext4: bitmap's paging->mapping != inode->i_mapping\n")) {
+			folio_put(folio);
+		folio = __filemap_get_folio(inode->i_mapping, pnum,
+				FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+		if (!IS_ERR(folio)) {
+			if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+	"ext4: bitmap's mapping != inode->i_mapping\n")) {
 				/* should never happen */
-				unlock_page(page);
+				folio_unlock(folio);
 				ret = -EINVAL;
 				goto err;
 			}
-			if (!PageUptodate(page)) {
-				ret = ext4_mb_init_cache(page, NULL, gfp);
+			if (!folio_test_uptodate(folio)) {
+				ret = ext4_mb_init_cache(&folio->page, NULL, gfp);
 				if (ret) {
-					unlock_page(page);
+					folio_unlock(folio);
 					goto err;
 				}
-				mb_cmp_bitmaps(e4b, page_address(page) +
+				mb_cmp_bitmaps(e4b, folio_address(folio) +
 					       (poff * sb->s_blocksize));
 			}
-			unlock_page(page);
+			folio_unlock(folio);
 		}
 	}
-	if (page == NULL) {
-		ret = -ENOMEM;
+	if (IS_ERR(folio)) {
+		ret = PTR_ERR(folio);
 		goto err;
 	}
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
 
 	/* Pages marked accessed already */
-	e4b->bd_bitmap_page = page;
-	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+	e4b->bd_bitmap_folio = folio;
+	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
 
 	block++;
 	pnum = block / blocks_per_page;
@@ -1711,8 +1715,8 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 err:
 	if (page)
 		put_page(page);
-	if (e4b->bd_bitmap_page)
-		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_bitmap_folio)
+		folio_put(e4b->bd_bitmap_folio);
 
 	e4b->bd_buddy = NULL;
 	e4b->bd_bitmap = NULL;
@@ -1727,8 +1731,8 @@ static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
 
 static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
 {
-	if (e4b->bd_bitmap_page)
-		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_bitmap_folio)
+		folio_put(e4b->bd_bitmap_folio);
 	if (e4b->bd_buddy_page)
 		put_page(e4b->bd_buddy_page);
 }
@@ -2149,7 +2153,7 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
 	 * double allocate blocks. The reference is dropped
 	 * in ext4_mb_release_context
 	 */
-	ac->ac_bitmap_page = e4b->bd_bitmap_page;
+	ac->ac_bitmap_page = &e4b->bd_bitmap_folio->page;
 	get_page(ac->ac_bitmap_page);
 	ac->ac_buddy_page = e4b->bd_buddy_page;
 	get_page(ac->ac_buddy_page);
@@ -3885,7 +3889,7 @@ static void ext4_free_data_in_buddy(struct super_block *sb,
 		 * balance refcounts from ext4_mb_free_metadata()
 		 */
 		put_page(e4b.bd_buddy_page);
-		put_page(e4b.bd_bitmap_page);
+		folio_put(e4b.bd_bitmap_folio);
 	}
 	ext4_unlock_group(sb, entry->efd_group);
 	ext4_mb_unload_buddy(&e4b);
@@ -6307,7 +6311,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
 	struct rb_node *parent = NULL, *new_node;
 
 	BUG_ON(!ext4_handle_valid(handle));
-	BUG_ON(e4b->bd_bitmap_page == NULL);
+	BUG_ON(e4b->bd_bitmap_folio == NULL);
 	BUG_ON(e4b->bd_buddy_page == NULL);
 
 	new_node = &new_entry->efd_node;
@@ -6320,7 +6324,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
 		 * on-disk bitmap and lose not-yet-available
 		 * blocks */
 		get_page(e4b->bd_buddy_page);
-		get_page(e4b->bd_bitmap_page);
+		folio_get(e4b->bd_bitmap_folio);
 	}
 	while (*n) {
 		parent = *n;
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 56938532b4ce..4725e5c9e482 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -217,7 +217,7 @@ struct ext4_allocation_context {
 struct ext4_buddy {
 	struct page *bd_buddy_page;
 	void *bd_buddy;
-	struct page *bd_bitmap_page;
+	struct folio *bd_bitmap_folio;
 	void *bd_bitmap;
 	struct ext4_group_info *bd_info;
 	struct super_block *bd_sb;
-- 
2.43.0

[PATCH 2/5] ext4: Convert bd_buddy_page to bd_buddy_folio

[Matthew Wilcox (Oracle)]

There is no need to make this a multi-page folio, so leave all the
infrastructure around it in pages.  But since we're locking it, playing
with its refcount and checking whether it's uptodate, it needs to move
to the folio API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ext4/mballoc.c | 91 +++++++++++++++++++++++------------------------
 fs/ext4/mballoc.h |  2 +-
 2 files changed, 46 insertions(+), 47 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 91c015fda370..761d8d15b205 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1439,7 +1439,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
  * Lock the buddy and bitmap pages. This make sure other parallel init_group
  * on the same buddy page doesn't happen whild holding the buddy page lock.
  * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
- * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
+ * are on the same page e4b->bd_buddy_folio is NULL and return value is 0.
  */
 static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 		ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
@@ -1447,10 +1447,9 @@ static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
 	int block, pnum, poff;
 	int blocks_per_page;
-	struct page *page;
 	struct folio *folio;
 
-	e4b->bd_buddy_page = NULL;
+	e4b->bd_buddy_folio = NULL;
 	e4b->bd_bitmap_folio = NULL;
 
 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
@@ -1476,11 +1475,12 @@ static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 	}
 
 	/* blocks_per_page == 1, hence we need another page for the buddy */
-	page = find_or_create_page(inode->i_mapping, block + 1, gfp);
-	if (!page)
-		return -ENOMEM;
-	BUG_ON(page->mapping != inode->i_mapping);
-	e4b->bd_buddy_page = page;
+	folio = __filemap_get_folio(inode->i_mapping, block + 1,
+			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	BUG_ON(folio->mapping != inode->i_mapping);
+	e4b->bd_buddy_folio = folio;
 	return 0;
 }
 
@@ -1490,9 +1490,9 @@ static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
 		folio_unlock(e4b->bd_bitmap_folio);
 		folio_put(e4b->bd_bitmap_folio);
 	}
-	if (e4b->bd_buddy_page) {
-		unlock_page(e4b->bd_buddy_page);
-		put_page(e4b->bd_buddy_page);
+	if (e4b->bd_buddy_folio) {
+		folio_unlock(e4b->bd_buddy_folio);
+		folio_put(e4b->bd_buddy_folio);
 	}
 }
 
@@ -1507,7 +1507,6 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 
 	struct ext4_group_info *this_grp;
 	struct ext4_buddy e4b;
-	struct page *page;
 	struct folio *folio;
 	int ret = 0;
 
@@ -1544,7 +1543,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 		goto err;
 	}
 
-	if (e4b.bd_buddy_page == NULL) {
+	if (e4b.bd_buddy_folio == NULL) {
 		/*
 		 * If both the bitmap and buddy are in
 		 * the same page we don't need to force
@@ -1554,11 +1553,11 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 		goto err;
 	}
 	/* init buddy cache */
-	page = e4b.bd_buddy_page;
-	ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
+	folio = e4b.bd_buddy_folio;
+	ret = ext4_mb_init_cache(&folio->page, e4b.bd_bitmap, gfp);
 	if (ret)
 		goto err;
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
@@ -1580,7 +1579,6 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	int block;
 	int pnum;
 	int poff;
-	struct page *page;
 	struct folio *folio;
 	int ret;
 	struct ext4_group_info *grp;
@@ -1599,7 +1597,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	e4b->bd_info = grp;
 	e4b->bd_sb = sb;
 	e4b->bd_group = group;
-	e4b->bd_buddy_page = NULL;
+	e4b->bd_buddy_folio = NULL;
 	e4b->bd_bitmap_folio = NULL;
 
 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
@@ -1665,7 +1663,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 		goto err;
 	}
 
-	/* Pages marked accessed already */
+	/* Folios marked accessed already */
 	e4b->bd_bitmap_folio = folio;
 	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
 
@@ -1673,48 +1671,49 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
 
-	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
-	if (page == NULL || !PageUptodate(page)) {
-		if (page)
-			put_page(page);
-		page = find_or_create_page(inode->i_mapping, pnum, gfp);
-		if (page) {
-			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
-	"ext4: buddy bitmap's page->mapping != inode->i_mapping\n")) {
+	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+		if (!IS_ERR(folio))
+			folio_put(folio);
+		folio = __filemap_get_folio(inode->i_mapping, pnum,
+				FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+		if (!IS_ERR(folio)) {
+			if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+	"ext4: buddy bitmap's mapping != inode->i_mapping\n")) {
 				/* should never happen */
-				unlock_page(page);
+				folio_unlock(folio);
 				ret = -EINVAL;
 				goto err;
 			}
-			if (!PageUptodate(page)) {
-				ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
+			if (!folio_test_uptodate(folio)) {
+				ret = ext4_mb_init_cache(&folio->page, e4b->bd_bitmap,
 							 gfp);
 				if (ret) {
-					unlock_page(page);
+					folio_unlock(folio);
 					goto err;
 				}
 			}
-			unlock_page(page);
+			folio_unlock(folio);
 		}
 	}
-	if (page == NULL) {
-		ret = -ENOMEM;
+	if (IS_ERR(folio)) {
+		ret = PTR_ERR(folio);
 		goto err;
 	}
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
 
-	/* Pages marked accessed already */
-	e4b->bd_buddy_page = page;
-	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
+	/* Folios marked accessed already */
+	e4b->bd_buddy_folio = folio;
+	e4b->bd_buddy = folio_address(folio) + (poff * sb->s_blocksize);
 
 	return 0;
 
 err:
-	if (page)
-		put_page(page);
+	if (folio)
+		folio_put(folio);
 	if (e4b->bd_bitmap_folio)
 		folio_put(e4b->bd_bitmap_folio);
 
@@ -1733,8 +1732,8 @@ static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
 {
 	if (e4b->bd_bitmap_folio)
 		folio_put(e4b->bd_bitmap_folio);
-	if (e4b->bd_buddy_page)
-		put_page(e4b->bd_buddy_page);
+	if (e4b->bd_buddy_folio)
+		folio_put(e4b->bd_buddy_folio);
 }
 
 
@@ -2155,7 +2154,7 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
 	 */
 	ac->ac_bitmap_page = &e4b->bd_bitmap_folio->page;
 	get_page(ac->ac_bitmap_page);
-	ac->ac_buddy_page = e4b->bd_buddy_page;
+	ac->ac_buddy_page = &e4b->bd_buddy_folio->page;
 	get_page(ac->ac_buddy_page);
 	/* store last allocated for subsequent stream allocation */
 	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
@@ -3888,7 +3887,7 @@ static void ext4_free_data_in_buddy(struct super_block *sb,
 		/* No more items in the per group rb tree
 		 * balance refcounts from ext4_mb_free_metadata()
 		 */
-		put_page(e4b.bd_buddy_page);
+		folio_put(e4b.bd_buddy_folio);
 		folio_put(e4b.bd_bitmap_folio);
 	}
 	ext4_unlock_group(sb, entry->efd_group);
@@ -6312,7 +6311,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
 
 	BUG_ON(!ext4_handle_valid(handle));
 	BUG_ON(e4b->bd_bitmap_folio == NULL);
-	BUG_ON(e4b->bd_buddy_page == NULL);
+	BUG_ON(e4b->bd_buddy_folio == NULL);
 
 	new_node = &new_entry->efd_node;
 	cluster = new_entry->efd_start_cluster;
@@ -6323,7 +6322,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
 		 * otherwise we'll refresh it from
 		 * on-disk bitmap and lose not-yet-available
 		 * blocks */
-		get_page(e4b->bd_buddy_page);
+		folio_get(e4b->bd_buddy_folio);
 		folio_get(e4b->bd_bitmap_folio);
 	}
 	while (*n) {
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 4725e5c9e482..720fb277abd2 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -215,7 +215,7 @@ struct ext4_allocation_context {
 #define AC_STATUS_BREAK		3
 
 struct ext4_buddy {
-	struct page *bd_buddy_page;
+	struct folio *bd_buddy_folio;
 	void *bd_buddy;
 	struct folio *bd_bitmap_folio;
 	void *bd_bitmap;
-- 
2.43.0

[PATCH 3/5] ext4: Convert ext4_mb_init_cache() to take a folio

[Matthew Wilcox (Oracle)]

All callers now have a folio, so convert this function from operating on
a page to operating on a folio.  The folio is assumed to be a single page.

Signe-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ext4/mballoc.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 761d8d15b205..50bdf3646d45 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1270,7 +1270,7 @@ static void mb_regenerate_buddy(struct ext4_buddy *e4b)
  * for this page; do not hold this lock when calling this routine!
  */
 
-static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
+static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 {
 	ext4_group_t ngroups;
 	unsigned int blocksize;
@@ -1288,13 +1288,13 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 	char *bitmap;
 	struct ext4_group_info *grinfo;
 
-	inode = page->mapping->host;
+	inode = folio->mapping->host;
 	sb = inode->i_sb;
 	ngroups = ext4_get_groups_count(sb);
 	blocksize = i_blocksize(inode);
 	blocks_per_page = PAGE_SIZE / blocksize;
 
-	mb_debug(sb, "init page %lu\n", page->index);
+	mb_debug(sb, "init folio %lu\n", folio->index);
 
 	groups_per_page = blocks_per_page >> 1;
 	if (groups_per_page == 0)
@@ -1309,9 +1309,9 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 	} else
 		bh = &bhs;
 
-	first_group = page->index * blocks_per_page / 2;
+	first_group = folio->index * blocks_per_page / 2;
 
-	/* read all groups the page covers into the cache */
+	/* read all groups the folio covers into the cache */
 	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
 		if (group >= ngroups)
 			break;
@@ -1322,10 +1322,11 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 		/*
 		 * If page is uptodate then we came here after online resize
 		 * which added some new uninitialized group info structs, so
-		 * we must skip all initialized uptodate buddies on the page,
+		 * we must skip all initialized uptodate buddies on the folio,
 		 * which may be currently in use by an allocating task.
 		 */
-		if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
+		if (folio_test_uptodate(folio) &&
+				!EXT4_MB_GRP_NEED_INIT(grinfo)) {
 			bh[i] = NULL;
 			continue;
 		}
@@ -1349,7 +1350,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 			err = err2;
 	}
 
-	first_block = page->index * blocks_per_page;
+	first_block = folio->index * blocks_per_page;
 	for (i = 0; i < blocks_per_page; i++) {
 		group = (first_block + i) >> 1;
 		if (group >= ngroups)
@@ -1370,7 +1371,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 		 * above
 		 *
 		 */
-		data = page_address(page) + (i * blocksize);
+		data = folio_address(folio) + (i * blocksize);
 		bitmap = bh[group - first_group]->b_data;
 
 		/*
@@ -1385,8 +1386,8 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 		if ((first_block + i) & 1) {
 			/* this is block of buddy */
 			BUG_ON(incore == NULL);
-			mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
-				group, page->index, i * blocksize);
+			mb_debug(sb, "put buddy for group %u in folio %lu/%x\n",
+				group, folio->index, i * blocksize);
 			trace_ext4_mb_buddy_bitmap_load(sb, group);
 			grinfo->bb_fragments = 0;
 			memset(grinfo->bb_counters, 0,
@@ -1404,8 +1405,8 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 		} else {
 			/* this is block of bitmap */
 			BUG_ON(incore != NULL);
-			mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
-				group, page->index, i * blocksize);
+			mb_debug(sb, "put bitmap for group %u in folio %lu/%x\n",
+				group, folio->index, i * blocksize);
 			trace_ext4_mb_bitmap_load(sb, group);
 
 			/* see comments in ext4_mb_put_pa() */
@@ -1423,7 +1424,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 			incore = data;
 		}
 	}
-	SetPageUptodate(page);
+	folio_mark_uptodate(folio);
 
 out:
 	if (bh) {
@@ -1535,7 +1536,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 	}
 
 	folio = e4b.bd_bitmap_folio;
-	ret = ext4_mb_init_cache(&folio->page, NULL, gfp);
+	ret = ext4_mb_init_cache(folio, NULL, gfp);
 	if (ret)
 		goto err;
 	if (!folio_test_uptodate(folio)) {
@@ -1554,7 +1555,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 	}
 	/* init buddy cache */
 	folio = e4b.bd_buddy_folio;
-	ret = ext4_mb_init_cache(&folio->page, e4b.bd_bitmap, gfp);
+	ret = ext4_mb_init_cache(folio, e4b.bd_bitmap, gfp);
 	if (ret)
 		goto err;
 	if (!folio_test_uptodate(folio)) {
@@ -1643,7 +1644,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 				goto err;
 			}
 			if (!folio_test_uptodate(folio)) {
-				ret = ext4_mb_init_cache(&folio->page, NULL, gfp);
+				ret = ext4_mb_init_cache(folio, NULL, gfp);
 				if (ret) {
 					folio_unlock(folio);
 					goto err;
@@ -1686,7 +1687,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 				goto err;
 			}
 			if (!folio_test_uptodate(folio)) {
-				ret = ext4_mb_init_cache(&folio->page, e4b->bd_bitmap,
+				ret = ext4_mb_init_cache(folio, e4b->bd_bitmap,
 							 gfp);
 				if (ret) {
 					folio_unlock(folio);
-- 
2.43.0

[PATCH 4/5] ext4: Convert ac_bitmap_page to ac_bitmap_folio

[Matthew Wilcox (Oracle)]

This just carries around the bd_bitmap_folio so should also be a folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ext4/mballoc.c | 8 ++++----
 fs/ext4/mballoc.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 50bdf3646d45..b2ea016f259d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2153,8 +2153,8 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
 	 * double allocate blocks. The reference is dropped
 	 * in ext4_mb_release_context
 	 */
-	ac->ac_bitmap_page = &e4b->bd_bitmap_folio->page;
-	get_page(ac->ac_bitmap_page);
+	ac->ac_bitmap_folio = e4b->bd_bitmap_folio;
+	folio_get(ac->ac_bitmap_folio);
 	ac->ac_buddy_page = &e4b->bd_buddy_folio->page;
 	get_page(ac->ac_buddy_page);
 	/* store last allocated for subsequent stream allocation */
@@ -5993,8 +5993,8 @@ static void ext4_mb_release_context(struct ext4_allocation_context *ac)
 
 		ext4_mb_put_pa(ac, ac->ac_sb, pa);
 	}
-	if (ac->ac_bitmap_page)
-		put_page(ac->ac_bitmap_page);
+	if (ac->ac_bitmap_folio)
+		folio_put(ac->ac_bitmap_folio);
 	if (ac->ac_buddy_page)
 		put_page(ac->ac_buddy_page);
 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 720fb277abd2..ec1348fe1c04 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -204,7 +204,7 @@ struct ext4_allocation_context {
 	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
 				 * N > 0, the field stores N, otherwise 0 */
 	__u8 ac_op;		/* operation, for history only */
-	struct page *ac_bitmap_page;
+	struct folio *ac_bitmap_folio;
 	struct page *ac_buddy_page;
 	struct ext4_prealloc_space *ac_pa;
 	struct ext4_locality_group *ac_lg;
-- 
2.43.0

[PATCH 5/5] ext4: Convert ac_buddy_page to ac_buddy_folio

[Matthew Wilcox (Oracle)]

This just carries around the bd_buddy_folio so should also be a folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ext4/mballoc.c | 8 ++++----
 fs/ext4/mballoc.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index b2ea016f259d..e63f7365ede3 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2155,8 +2155,8 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
 	 */
 	ac->ac_bitmap_folio = e4b->bd_bitmap_folio;
 	folio_get(ac->ac_bitmap_folio);
-	ac->ac_buddy_page = &e4b->bd_buddy_folio->page;
-	get_page(ac->ac_buddy_page);
+	ac->ac_buddy_folio = e4b->bd_buddy_folio;
+	folio_get(ac->ac_buddy_folio);
 	/* store last allocated for subsequent stream allocation */
 	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
 		spin_lock(&sbi->s_md_lock);
@@ -5995,8 +5995,8 @@ static void ext4_mb_release_context(struct ext4_allocation_context *ac)
 	}
 	if (ac->ac_bitmap_folio)
 		folio_put(ac->ac_bitmap_folio);
-	if (ac->ac_buddy_page)
-		put_page(ac->ac_buddy_page);
+	if (ac->ac_buddy_folio)
+		folio_put(ac->ac_buddy_folio);
 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
 		mutex_unlock(&ac->ac_lg->lg_mutex);
 	ext4_mb_collect_stats(ac);
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index ec1348fe1c04..728b2d77b03f 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -205,7 +205,7 @@ struct ext4_allocation_context {
 				 * N > 0, the field stores N, otherwise 0 */
 	__u8 ac_op;		/* operation, for history only */
 	struct folio *ac_bitmap_folio;
-	struct page *ac_buddy_page;
+	struct folio *ac_buddy_folio;
 	struct ext4_prealloc_space *ac_pa;
 	struct ext4_locality_group *ac_lg;
 };
-- 
2.43.0

Re: [PATCH 0/5] Convert ext4's mballoc to use folios

[Theodore Ts'o]

On Tue, 16 Apr 2024 18:28:53 +0100, Matthew Wilcox (Oracle) wrote:
> These pages are stored in the page cache, so they're really folios.
> Convert the whole file from pages to folios.
> 
> Matthew Wilcox (Oracle) (5):
>   ext4: Convert bd_bitmap_page to bd_bitmap_folio
>   ext4: Convert bd_buddy_page to bd_buddy_folio
>   ext4: Convert ext4_mb_init_cache() to take a folio
>   ext4: Convert ac_bitmap_page to ac_bitmap_folio
>   ext4: Convert ac_buddy_page to ac_buddy_folio
> 
> [...]

Applied, thanks!

[1/5] ext4: Convert bd_bitmap_page to bd_bitmap_folio
      commit: 99b150d84e4939735cfce245e32e3d29312c68ec
[2/5] ext4: Convert bd_buddy_page to bd_buddy_folio
      commit: 5eea586b47f05b5f5518cf8f9dd9283a01a8066d
[3/5] ext4: Convert ext4_mb_init_cache() to take a folio
      commit: e1622a0d558200b0ccdfbf69ee29b9ac1f5c2442
[4/5] ext4: Convert ac_bitmap_page to ac_bitmap_folio
      commit: ccedf35b5daa429c0e731eac6fb32b0208302c6b
[5/5] ext4: Convert ac_buddy_page to ac_buddy_folio
      commit: c84f1510fba9fb181e6a1aa7b5fcfc67381b39c9

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>

Re: [PATCH 0/5] Convert ext4's mballoc to use folios

[Matthew Wilcox]

On Tue, May 07, 2024 at 07:03:53PM -0400, Theodore Ts'o wrote:
> 
> On Tue, 16 Apr 2024 18:28:53 +0100, Matthew Wilcox (Oracle) wrote:
> > These pages are stored in the page cache, so they're really folios.
> > Convert the whole file from pages to folios.
> > 
> > Matthew Wilcox (Oracle) (5):
> >   ext4: Convert bd_bitmap_page to bd_bitmap_folio
> >   ext4: Convert bd_buddy_page to bd_buddy_folio
> >   ext4: Convert ext4_mb_init_cache() to take a folio
> >   ext4: Convert ac_bitmap_page to ac_bitmap_folio
> >   ext4: Convert ac_buddy_page to ac_buddy_folio
> > 
> > [...]
> 
> Applied, thanks!

Thanks!  Can you also add 20240420025029.2166544-11-willy@infradead.org

Re: [PATCH 0/5] Convert ext4's mballoc to use folios

[Theodore Ts'o]

On Wed, May 08, 2024 at 04:20:19PM +0100, Matthew Wilcox wrote:
> 
> Thanks!  Can you also add 20240420025029.2166544-11-willy@infradead.org

Thanks, done.

						- Ted