[PATCH v2 00/13] JFS folio conversion

[PATCH v2 00/13] JFS folio conversion

[Matthew Wilcox (Oracle)]

This patchset removes uses of struct page from the I/O paths of JFS.
write_begin and write_end are still passed a struct page, but they convert
to a folio as their first thing.  The logmgr still uses a struct page,
but I think that's one we actually don't want to convert since it's
never inserted into the page cache.

I've included the removal of i_blocks_per_page() in this series as JFS
is the last user.

Tested with xfstests; some failures observed, but they don't seem to be
related to these patches.  I haven't tried with PAGE_SIZE > 4kB, so the
MPS_PER_PAGE > 1 paths are untested.

v2:
 - Fix build errors on machines with PAGE_SIZE > 4096

Matthew Wilcox (Oracle) (13):
  jfs: Convert metapage_read_folio to use folio APIs
  jfs: Convert metapage_writepage to metapage_write_folio
  jfs: Convert __get_metapage to use a folio
  jfs: Convert insert_metapage() to take a folio
  jfs; Convert release_metapage to use a folio
  jfs: Convert drop_metapage and remove_metapage to take a folio
  jfs: Convert dec_io to take a folio
  jfs; Convert __invalidate_metapages to use a folio
  jfs: Convert page_to_mp to folio_to_mp
  jfs: Convert inc_io to take a folio
  jfs: Convert force_metapage to use a folio
  jfs: Change metapage->page to metapage->folio
  fs: Remove i_blocks_per_page

 fs/jfs/jfs_logmgr.c     |   2 +-
 fs/jfs/jfs_metapage.c   | 299 ++++++++++++++++++++--------------------
 fs/jfs/jfs_metapage.h   |  16 +--
 include/linux/pagemap.h |   6 -
 4 files changed, 156 insertions(+), 167 deletions(-)

-- 
2.43.0

[PATCH v2 01/13] jfs: Convert metapage_read_folio to use folio APIs

[Matthew Wilcox (Oracle)]

Use bio_add_folio_nofail() as we just allocated the bio and know
it cannot fail.  Other than that, this is a 1:1 conversion from
page APIs to folio APIs.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 35 +++++++++++++----------------------
 1 file changed, 13 insertions(+), 22 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 961569c11159..8266c43ec728 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -266,14 +266,14 @@ static void last_read_complete(struct page *page)
 
 static void metapage_read_end_io(struct bio *bio)
 {
-	struct page *page = bio->bi_private;
+	struct folio *folio = bio->bi_private;
 
 	if (bio->bi_status) {
 		printk(KERN_ERR "metapage_read_end_io: I/O error\n");
-		SetPageError(page);
+		folio_set_error(folio);
 	}
 
-	dec_io(page, last_read_complete);
+	dec_io(&folio->page, last_read_complete);
 	bio_put(bio);
 }
 
@@ -469,20 +469,18 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 
 static int metapage_read_folio(struct file *fp, struct folio *folio)
 {
-	struct page *page = &folio->page;
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	struct bio *bio = NULL;
 	int block_offset;
-	int blocks_per_page = i_blocks_per_page(inode, page);
+	int blocks_per_page = i_blocks_per_folio(inode, folio);
 	sector_t page_start;	/* address of page in fs blocks */
 	sector_t pblock;
 	int xlen;
 	unsigned int len;
 	int offset;
 
-	BUG_ON(!PageLocked(page));
-	page_start = (sector_t)page->index <<
-		     (PAGE_SHIFT - inode->i_blkbits);
+	BUG_ON(!folio_test_locked(folio));
+	page_start = folio_pos(folio) >> inode->i_blkbits;
 
 	block_offset = 0;
 	while (block_offset < blocks_per_page) {
@@ -490,9 +488,9 @@ static int metapage_read_folio(struct file *fp, struct folio *folio)
 		pblock = metapage_get_blocks(inode, page_start + block_offset,
 					     &xlen);
 		if (pblock) {
-			if (!PagePrivate(page))
-				insert_metapage(page, NULL);
-			inc_io(page);
+			if (!folio->private)
+				insert_metapage(&folio->page, NULL);
+			inc_io(&folio->page);
 			if (bio)
 				submit_bio(bio);
 
@@ -501,11 +499,10 @@ static int metapage_read_folio(struct file *fp, struct folio *folio)
 			bio->bi_iter.bi_sector =
 				pblock << (inode->i_blkbits - 9);
 			bio->bi_end_io = metapage_read_end_io;
-			bio->bi_private = page;
+			bio->bi_private = folio;
 			len = xlen << inode->i_blkbits;
 			offset = block_offset << inode->i_blkbits;
-			if (bio_add_page(bio, page, len, offset) < len)
-				goto add_failed;
+			bio_add_folio_nofail(bio, folio, len, offset);
 			block_offset += xlen;
 		} else
 			block_offset++;
@@ -513,15 +510,9 @@ static int metapage_read_folio(struct file *fp, struct folio *folio)
 	if (bio)
 		submit_bio(bio);
 	else
-		unlock_page(page);
+		folio_unlock(folio);
 
 	return 0;
-
-add_failed:
-	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
-	bio_put(bio);
-	dec_io(page, last_read_complete);
-	return -EIO;
 }
 
 static bool metapage_release_folio(struct folio *folio, gfp_t gfp_mask)
-- 
2.43.0

[PATCH v2 02/13] jfs: Convert metapage_writepage to metapage_write_folio

[Matthew Wilcox (Oracle)]

Implement writepages rather than writepage by using write_cache_pages()
to call metapage_write_folio().  Use bio_add_folio_nofail() as we know
we just allocated the bio.  Replace the call to SetPageError (which
is never checked) with a call to mapping_set_error (which ... might be
checked somewhere?)

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 75 +++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 34 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 8266c43ec728..beecc9ad656e 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -4,6 +4,7 @@
  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
  */
 
+#include <linux/blkdev.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/module.h>
@@ -321,23 +322,25 @@ static void last_write_complete(struct page *page)
 
 static void metapage_write_end_io(struct bio *bio)
 {
-	struct page *page = bio->bi_private;
+	struct folio *folio = bio->bi_private;
 
-	BUG_ON(!PagePrivate(page));
+	BUG_ON(!folio->private);
 
 	if (bio->bi_status) {
+		int err = blk_status_to_errno(bio->bi_status);
 		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
-		SetPageError(page);
+		mapping_set_error(folio->mapping, err);
 	}
-	dec_io(page, last_write_complete);
+	dec_io(&folio->page, last_write_complete);
 	bio_put(bio);
 }
 
-static int metapage_writepage(struct page *page, struct writeback_control *wbc)
+static int metapage_write_folio(struct folio *folio,
+		struct writeback_control *wbc, void *unused)
 {
 	struct bio *bio = NULL;
 	int block_offset;	/* block offset of mp within page */
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
 	int len;
 	int xlen;
@@ -353,14 +356,13 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 	int offset;
 	int bad_blocks = 0;
 
-	page_start = (sector_t)page->index <<
-		     (PAGE_SHIFT - inode->i_blkbits);
-	BUG_ON(!PageLocked(page));
-	BUG_ON(PageWriteback(page));
-	set_page_writeback(page);
+	page_start = folio_pos(folio) >> inode->i_blkbits;
+	BUG_ON(!folio_test_locked(folio));
+	BUG_ON(folio_test_writeback(folio));
+	folio_start_writeback(folio);
 
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-		mp = page_to_mp(page, offset);
+		mp = page_to_mp(&folio->page, offset);
 
 		if (!mp || !test_bit(META_dirty, &mp->flag))
 			continue;
@@ -389,22 +391,20 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 				continue;
 			}
 			/* Not contiguous */
-			if (bio_add_page(bio, page, bio_bytes, bio_offset) <
-			    bio_bytes)
-				goto add_failed;
+			bio_add_folio_nofail(bio, folio, bio_bytes, bio_offset);
 			/*
 			 * Increment counter before submitting i/o to keep
 			 * count from hitting zero before we're through
 			 */
-			inc_io(page);
+			inc_io(&folio->page);
 			if (!bio->bi_iter.bi_size)
 				goto dump_bio;
 			submit_bio(bio);
 			nr_underway++;
 			bio = NULL;
 		} else
-			inc_io(page);
-		xlen = (PAGE_SIZE - offset) >> inode->i_blkbits;
+			inc_io(&folio->page);
+		xlen = (folio_size(folio) - offset) >> inode->i_blkbits;
 		pblock = metapage_get_blocks(inode, lblock, &xlen);
 		if (!pblock) {
 			printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
@@ -420,7 +420,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 		bio = bio_alloc(inode->i_sb->s_bdev, 1, REQ_OP_WRITE, GFP_NOFS);
 		bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9);
 		bio->bi_end_io = metapage_write_end_io;
-		bio->bi_private = page;
+		bio->bi_private = folio;
 
 		/* Don't call bio_add_page yet, we may add to this vec */
 		bio_offset = offset;
@@ -430,8 +430,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 		next_block = lblock + len;
 	}
 	if (bio) {
-		if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
-				goto add_failed;
+		bio_add_folio_nofail(bio, folio, bio_bytes, bio_offset);
 		if (!bio->bi_iter.bi_size)
 			goto dump_bio;
 
@@ -439,34 +438,42 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 		nr_underway++;
 	}
 	if (redirty)
-		redirty_page_for_writepage(wbc, page);
+		folio_redirty_for_writepage(wbc, folio);
 
-	unlock_page(page);
+	folio_unlock(folio);
 
 	if (bad_blocks)
 		goto err_out;
 
 	if (nr_underway == 0)
-		end_page_writeback(page);
+		folio_end_writeback(folio);
 
 	return 0;
-add_failed:
-	/* We should never reach here, since we're only adding one vec */
-	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
-	goto skip;
 dump_bio:
 	print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
 		       4, bio, sizeof(*bio), 0);
-skip:
 	bio_put(bio);
-	unlock_page(page);
-	dec_io(page, last_write_complete);
+	folio_unlock(folio);
+	dec_io(&folio->page, last_write_complete);
 err_out:
 	while (bad_blocks--)
-		dec_io(page, last_write_complete);
+		dec_io(&folio->page, last_write_complete);
 	return -EIO;
 }
 
+static int metapage_writepages(struct address_space *mapping,
+		struct writeback_control *wbc)
+{
+	struct blk_plug plug;
+	int err;
+
+	blk_start_plug(&plug);
+	err = write_cache_pages(mapping, wbc, metapage_write_folio, NULL);
+	blk_finish_plug(&plug);
+
+	return err;
+}
+
 static int metapage_read_folio(struct file *fp, struct folio *folio)
 {
 	struct inode *inode = folio->mapping->host;
@@ -556,7 +563,7 @@ static void metapage_invalidate_folio(struct folio *folio, size_t offset,
 
 const struct address_space_operations jfs_metapage_aops = {
 	.read_folio	= metapage_read_folio,
-	.writepage	= metapage_writepage,
+	.writepages	= metapage_writepages,
 	.release_folio	= metapage_release_folio,
 	.invalidate_folio = metapage_invalidate_folio,
 	.dirty_folio	= filemap_dirty_folio,
@@ -698,7 +705,7 @@ static int metapage_write_one(struct page *page)
 
 	if (folio_clear_dirty_for_io(folio)) {
 		folio_get(folio);
-		ret = metapage_writepage(page, &wbc);
+		ret = metapage_write_folio(folio, &wbc, NULL);
 		if (ret == 0)
 			folio_wait_writeback(folio);
 		folio_put(folio);
-- 
2.43.0

[PATCH v2 03/13] jfs: Convert __get_metapage to use a folio

[Matthew Wilcox (Oracle)]

Remove four hidden calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index beecc9ad656e..4ef85e264f51 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -577,7 +577,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 	int l2bsize;
 	struct address_space *mapping;
 	struct metapage *mp = NULL;
-	struct page *page;
+	struct folio *folio;
 	unsigned long page_index;
 	unsigned long page_offset;
 
@@ -608,22 +608,22 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 	}
 
 	if (new && (PSIZE == PAGE_SIZE)) {
-		page = grab_cache_page(mapping, page_index);
-		if (!page) {
-			jfs_err("grab_cache_page failed!");
+		folio = filemap_grab_folio(mapping, page_index);
+		if (IS_ERR(folio)) {
+			jfs_err("filemap_grab_folio failed!");
 			return NULL;
 		}
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	} else {
-		page = read_mapping_page(mapping, page_index, NULL);
-		if (IS_ERR(page)) {
+		folio = read_mapping_folio(mapping, page_index, NULL);
+		if (IS_ERR(folio)) {
 			jfs_err("read_mapping_page failed!");
 			return NULL;
 		}
-		lock_page(page);
+		folio_lock(folio);
 	}
 
-	mp = page_to_mp(page, page_offset);
+	mp = page_to_mp(&folio->page, page_offset);
 	if (mp) {
 		if (mp->logical_size != size) {
 			jfs_error(inode->i_sb,
@@ -649,16 +649,16 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		mp = alloc_metapage(GFP_NOFS);
 		if (!mp)
 			goto unlock;
-		mp->page = page;
+		mp->page = &folio->page;
 		mp->sb = inode->i_sb;
 		mp->flag = 0;
 		mp->xflag = COMMIT_PAGE;
 		mp->count = 1;
 		mp->nohomeok = 0;
 		mp->logical_size = size;
-		mp->data = page_address(page) + page_offset;
+		mp->data = folio_address(folio) + page_offset;
 		mp->index = lblock;
-		if (unlikely(insert_metapage(page, mp))) {
+		if (unlikely(insert_metapage(&folio->page, mp))) {
 			free_metapage(mp);
 			goto unlock;
 		}
@@ -670,12 +670,12 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		memset(mp->data, 0, PSIZE);
 	}
 
-	unlock_page(page);
+	folio_unlock(folio);
 	jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
 	return mp;
 
 unlock:
-	unlock_page(page);
+	folio_unlock(folio);
 	return NULL;
 }
 
-- 
2.43.0

[PATCH v2 04/13] jfs: Convert insert_metapage() to take a folio

[Matthew Wilcox (Oracle)]

Both of its callers now have a folio, so convert this function.
Use folio_attach_private() instead of manually setting folio->private.
This also gets the expected refcount of the folio correct.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 4ef85e264f51..6fa7023f5bc9 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -87,25 +87,23 @@ static inline struct metapage *page_to_mp(struct page *page, int offset)
 	return mp_anchor(page)->mp[offset >> L2PSIZE];
 }
 
-static inline int insert_metapage(struct page *page, struct metapage *mp)
+static inline int insert_metapage(struct folio *folio, struct metapage *mp)
 {
 	struct meta_anchor *a;
 	int index;
 	int l2mp_blocks;	/* log2 blocks per metapage */
 
-	if (PagePrivate(page))
-		a = mp_anchor(page);
-	else {
+	a = folio->private;
+	if (!a) {
 		a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
 		if (!a)
 			return -ENOMEM;
-		set_page_private(page, (unsigned long)a);
-		SetPagePrivate(page);
-		kmap(page);
+		folio_attach_private(folio, a);
+		kmap(&folio->page);
 	}
 
 	if (mp) {
-		l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
+		l2mp_blocks = L2PSIZE - folio->mapping->host->i_blkbits;
 		index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 		a->mp_count++;
 		a->mp[index] = mp;
@@ -127,8 +125,7 @@ static inline void remove_metapage(struct page *page, struct metapage *mp)
 	a->mp[index] = NULL;
 	if (--a->mp_count == 0) {
 		kfree(a);
-		set_page_private(page, 0);
-		ClearPagePrivate(page);
+		detach_page_private(page);
 		kunmap(page);
 	}
 }
@@ -150,20 +147,18 @@ static inline struct metapage *page_to_mp(struct page *page, int offset)
 	return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
 }
 
-static inline int insert_metapage(struct page *page, struct metapage *mp)
+static inline int insert_metapage(struct folio *folio, struct metapage *mp)
 {
 	if (mp) {
-		set_page_private(page, (unsigned long)mp);
-		SetPagePrivate(page);
-		kmap(page);
+		folio_attach_private(folio, mp);
+		kmap(&folio->page);
 	}
 	return 0;
 }
 
 static inline void remove_metapage(struct page *page, struct metapage *mp)
 {
-	set_page_private(page, 0);
-	ClearPagePrivate(page);
+	detach_page_private(page);
 	kunmap(page);
 }
 
@@ -496,7 +491,7 @@ static int metapage_read_folio(struct file *fp, struct folio *folio)
 					     &xlen);
 		if (pblock) {
 			if (!folio->private)
-				insert_metapage(&folio->page, NULL);
+				insert_metapage(folio, NULL);
 			inc_io(&folio->page);
 			if (bio)
 				submit_bio(bio);
@@ -658,7 +653,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		mp->logical_size = size;
 		mp->data = folio_address(folio) + page_offset;
 		mp->index = lblock;
-		if (unlikely(insert_metapage(&folio->page, mp))) {
+		if (unlikely(insert_metapage(folio, mp))) {
 			free_metapage(mp);
 			goto unlock;
 		}
-- 
2.43.0

[PATCH v2 05/13] jfs; Convert release_metapage to use a folio

[Matthew Wilcox (Oracle)]

Convert mp->page to a folio and remove 7 hidden calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 6fa7023f5bc9..4515dc1ac40e 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -749,37 +749,35 @@ void put_metapage(struct metapage *mp)
 
 void release_metapage(struct metapage * mp)
 {
-	struct page *page = mp->page;
+	struct folio *folio = page_folio(mp->page);
 	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 
-	BUG_ON(!page);
-
-	lock_page(page);
+	folio_lock(folio);
 	unlock_metapage(mp);
 
 	assert(mp->count);
 	if (--mp->count || mp->nohomeok) {
-		unlock_page(page);
-		put_page(page);
+		folio_unlock(folio);
+		folio_put(folio);
 		return;
 	}
 
 	if (test_bit(META_dirty, &mp->flag)) {
-		set_page_dirty(page);
+		folio_mark_dirty(folio);
 		if (test_bit(META_sync, &mp->flag)) {
 			clear_bit(META_sync, &mp->flag);
-			if (metapage_write_one(page))
+			if (metapage_write_one(&folio->page))
 				jfs_error(mp->sb, "metapage_write_one() failed\n");
-			lock_page(page);
+			folio_lock(folio);
 		}
 	} else if (mp->lsn)	/* discard_metapage doesn't remove it */
 		remove_from_logsync(mp);
 
 	/* Try to keep metapages from using up too much memory */
-	drop_metapage(page, mp);
+	drop_metapage(&folio->page, mp);
 
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 }
 
 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
-- 
2.43.0

[PATCH v2 06/13] jfs: Convert drop_metapage and remove_metapage to take a folio

[Matthew Wilcox (Oracle)]

All callers now have a folio, so pass it in instead of the page.
Removes a couple of calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 4515dc1ac40e..9fc52c27b0ce 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -112,10 +112,10 @@ static inline int insert_metapage(struct folio *folio, struct metapage *mp)
 	return 0;
 }
 
-static inline void remove_metapage(struct page *page, struct metapage *mp)
+static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 {
-	struct meta_anchor *a = mp_anchor(page);
-	int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
+	struct meta_anchor *a = folio->private;
+	int l2mp_blocks = L2PSIZE - folio->mapping->host->i_blkbits;
 	int index;
 
 	index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
@@ -125,8 +125,8 @@ static inline void remove_metapage(struct page *page, struct metapage *mp)
 	a->mp[index] = NULL;
 	if (--a->mp_count == 0) {
 		kfree(a);
-		detach_page_private(page);
-		kunmap(page);
+		folio_detach_private(folio);
+		kunmap(&folio->page);
 	}
 }
 
@@ -156,10 +156,10 @@ static inline int insert_metapage(struct folio *folio, struct metapage *mp)
 	return 0;
 }
 
-static inline void remove_metapage(struct page *page, struct metapage *mp)
+static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 {
-	detach_page_private(page);
-	kunmap(page);
+	folio_detach_private(folio);
+	kunmap(&folio->page);
 }
 
 #define inc_io(page) do {} while(0)
@@ -214,12 +214,12 @@ void metapage_exit(void)
 	kmem_cache_destroy(metapage_cache);
 }
 
-static inline void drop_metapage(struct page *page, struct metapage *mp)
+static inline void drop_metapage(struct folio *folio, struct metapage *mp)
 {
 	if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
 	    test_bit(META_io, &mp->flag))
 		return;
-	remove_metapage(page, mp);
+	remove_metapage(folio, mp);
 	INCREMENT(mpStat.pagefree);
 	free_metapage(mp);
 }
@@ -539,7 +539,7 @@ static bool metapage_release_folio(struct folio *folio, gfp_t gfp_mask)
 		}
 		if (mp->lsn)
 			remove_from_logsync(mp);
-		remove_metapage(&folio->page, mp);
+		remove_metapage(folio, mp);
 		INCREMENT(mpStat.pagefree);
 		free_metapage(mp);
 	}
@@ -774,7 +774,7 @@ void release_metapage(struct metapage * mp)
 		remove_from_logsync(mp);
 
 	/* Try to keep metapages from using up too much memory */
-	drop_metapage(&folio->page, mp);
+	drop_metapage(folio, mp);
 
 	folio_unlock(folio);
 	folio_put(folio);
-- 
2.43.0

[PATCH v2 07/13] jfs: Convert dec_io to take a folio

[Matthew Wilcox (Oracle)]

This means also converting the two handlers to take a folio.
Saves four calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 9fc52c27b0ce..dd540df0a617 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -135,10 +135,12 @@ static inline void inc_io(struct page *page)
 	atomic_inc(&mp_anchor(page)->io_count);
 }
 
-static inline void dec_io(struct page *page, void (*handler) (struct page *))
+static inline void dec_io(struct folio *folio, void (*handler) (struct folio *))
 {
-	if (atomic_dec_and_test(&mp_anchor(page)->io_count))
-		handler(page);
+	struct meta_anchor *anchor = folio->private;
+
+	if (atomic_dec_and_test(&anchor->io_count))
+		handler(folio);
 }
 
 #else
@@ -163,7 +165,7 @@ static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 }
 
 #define inc_io(page) do {} while(0)
-#define dec_io(page, handler) handler(page)
+#define dec_io(folio, handler) handler(folio)
 
 #endif
 
@@ -253,11 +255,11 @@ static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
 	return lblock;
 }
 
-static void last_read_complete(struct page *page)
+static void last_read_complete(struct folio *folio)
 {
-	if (!PageError(page))
-		SetPageUptodate(page);
-	unlock_page(page);
+	if (!folio_test_error(folio))
+		folio_mark_uptodate(folio);
+	folio_unlock(folio);
 }
 
 static void metapage_read_end_io(struct bio *bio)
@@ -269,7 +271,7 @@ static void metapage_read_end_io(struct bio *bio)
 		folio_set_error(folio);
 	}
 
-	dec_io(&folio->page, last_read_complete);
+	dec_io(folio, last_read_complete);
 	bio_put(bio);
 }
 
@@ -295,13 +297,13 @@ static void remove_from_logsync(struct metapage *mp)
 	LOGSYNC_UNLOCK(log, flags);
 }
 
-static void last_write_complete(struct page *page)
+static void last_write_complete(struct folio *folio)
 {
 	struct metapage *mp;
 	unsigned int offset;
 
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-		mp = page_to_mp(page, offset);
+		mp = page_to_mp(&folio->page, offset);
 		if (mp && test_bit(META_io, &mp->flag)) {
 			if (mp->lsn)
 				remove_from_logsync(mp);
@@ -312,7 +314,7 @@ static void last_write_complete(struct page *page)
 		 * safe unless I have the page locked
 		 */
 	}
-	end_page_writeback(page);
+	folio_end_writeback(folio);
 }
 
 static void metapage_write_end_io(struct bio *bio)
@@ -326,7 +328,7 @@ static void metapage_write_end_io(struct bio *bio)
 		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
 		mapping_set_error(folio->mapping, err);
 	}
-	dec_io(&folio->page, last_write_complete);
+	dec_io(folio, last_write_complete);
 	bio_put(bio);
 }
 
@@ -449,10 +451,10 @@ static int metapage_write_folio(struct folio *folio,
 		       4, bio, sizeof(*bio), 0);
 	bio_put(bio);
 	folio_unlock(folio);
-	dec_io(&folio->page, last_write_complete);
+	dec_io(folio, last_write_complete);
 err_out:
 	while (bad_blocks--)
-		dec_io(&folio->page, last_write_complete);
+		dec_io(folio, last_write_complete);
 	return -EIO;
 }
 
-- 
2.43.0

[PATCH v2 08/13] jfs; Convert __invalidate_metapages to use a folio

[Matthew Wilcox (Oracle)]

Retrieve a folio from the page cache instead of a page.  Saves a
couple of calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index dd540df0a617..90a284d3bef7 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -791,7 +791,6 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 	struct address_space *mapping =
 		JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
 	struct metapage *mp;
-	struct page *page;
 	unsigned int offset;
 
 	/*
@@ -800,11 +799,12 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 	 */
 	for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
 	     lblock += BlocksPerPage) {
-		page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
-		if (!page)
+		struct folio *folio = filemap_lock_folio(mapping,
+				lblock >> l2BlocksPerPage);
+		if (IS_ERR(folio))
 			continue;
 		for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-			mp = page_to_mp(page, offset);
+			mp = page_to_mp(&folio->page, offset);
 			if (!mp)
 				continue;
 			if (mp->index < addr)
@@ -817,8 +817,8 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 			if (mp->lsn)
 				remove_from_logsync(mp);
 		}
-		unlock_page(page);
-		put_page(page);
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 }
 
-- 
2.43.0

[PATCH v2 09/13] jfs: Convert page_to_mp to folio_to_mp

[Matthew Wilcox (Oracle)]

Access folio->private directly instead of testing the page private flag.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 90a284d3bef7..67d5d417fe01 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -80,11 +80,13 @@ struct meta_anchor {
 };
 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
 
-static inline struct metapage *page_to_mp(struct page *page, int offset)
+static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
 {
-	if (!PagePrivate(page))
+	struct meta_anchor *anchor = folio->private;
+
+	if (!anchor)
 		return NULL;
-	return mp_anchor(page)->mp[offset >> L2PSIZE];
+	return anchor->mp[offset >> L2PSIZE];
 }
 
 static inline int insert_metapage(struct folio *folio, struct metapage *mp)
@@ -144,9 +146,9 @@ static inline void dec_io(struct folio *folio, void (*handler) (struct folio *))
 }
 
 #else
-static inline struct metapage *page_to_mp(struct page *page, int offset)
+static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
 {
-	return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
+	return folio->private;
 }
 
 static inline int insert_metapage(struct folio *folio, struct metapage *mp)
@@ -303,7 +305,7 @@ static void last_write_complete(struct folio *folio)
 	unsigned int offset;
 
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-		mp = page_to_mp(&folio->page, offset);
+		mp = folio_to_mp(folio, offset);
 		if (mp && test_bit(META_io, &mp->flag)) {
 			if (mp->lsn)
 				remove_from_logsync(mp);
@@ -359,7 +361,7 @@ static int metapage_write_folio(struct folio *folio,
 	folio_start_writeback(folio);
 
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-		mp = page_to_mp(&folio->page, offset);
+		mp = folio_to_mp(folio, offset);
 
 		if (!mp || !test_bit(META_dirty, &mp->flag))
 			continue;
@@ -526,7 +528,7 @@ static bool metapage_release_folio(struct folio *folio, gfp_t gfp_mask)
 	int offset;
 
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-		mp = page_to_mp(&folio->page, offset);
+		mp = folio_to_mp(folio, offset);
 
 		if (!mp)
 			continue;
@@ -620,7 +622,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		folio_lock(folio);
 	}
 
-	mp = page_to_mp(&folio->page, page_offset);
+	mp = folio_to_mp(folio, page_offset);
 	if (mp) {
 		if (mp->logical_size != size) {
 			jfs_error(inode->i_sb,
@@ -804,7 +806,7 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 		if (IS_ERR(folio))
 			continue;
 		for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
-			mp = page_to_mp(&folio->page, offset);
+			mp = folio_to_mp(folio, offset);
 			if (!mp)
 				continue;
 			if (mp->index < addr)
-- 
2.43.0

[PATCH v2 10/13] jfs: Convert inc_io to take a folio

[Matthew Wilcox (Oracle)]

All their callers now have a folio, so pass it in.  Remove mp_anchor()
as inc_io() was the last user.  No savings here, just cleaning up some
remnants.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 67d5d417fe01..f03e217ec1cb 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -78,7 +78,6 @@ struct meta_anchor {
 	atomic_t io_count;
 	struct metapage *mp[MPS_PER_PAGE];
 };
-#define mp_anchor(page) ((struct meta_anchor *)page_private(page))
 
 static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
 {
@@ -132,9 +131,11 @@ static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 	}
 }
 
-static inline void inc_io(struct page *page)
+static inline void inc_io(struct folio *folio)
 {
-	atomic_inc(&mp_anchor(page)->io_count);
+	struct meta_anchor *anchor = folio->private;
+
+	atomic_inc(&anchor->io_count);
 }
 
 static inline void dec_io(struct folio *folio, void (*handler) (struct folio *))
@@ -166,7 +167,7 @@ static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 	kunmap(&folio->page);
 }
 
-#define inc_io(page) do {} while(0)
+#define inc_io(folio) do {} while(0)
 #define dec_io(folio, handler) handler(folio)
 
 #endif
@@ -395,14 +396,14 @@ static int metapage_write_folio(struct folio *folio,
 			 * Increment counter before submitting i/o to keep
 			 * count from hitting zero before we're through
 			 */
-			inc_io(&folio->page);
+			inc_io(folio);
 			if (!bio->bi_iter.bi_size)
 				goto dump_bio;
 			submit_bio(bio);
 			nr_underway++;
 			bio = NULL;
 		} else
-			inc_io(&folio->page);
+			inc_io(folio);
 		xlen = (folio_size(folio) - offset) >> inode->i_blkbits;
 		pblock = metapage_get_blocks(inode, lblock, &xlen);
 		if (!pblock) {
@@ -496,7 +497,7 @@ static int metapage_read_folio(struct file *fp, struct folio *folio)
 		if (pblock) {
 			if (!folio->private)
 				insert_metapage(folio, NULL);
-			inc_io(&folio->page);
+			inc_io(folio);
 			if (bio)
 				submit_bio(bio);
 
-- 
2.43.0

[PATCH v2 11/13] jfs: Convert force_metapage to use a folio

[Matthew Wilcox (Oracle)]

Convert the mp->page to a folio and operate on it.  That lets us
convert metapage_write_one() to take a folio.  Replaces five calls to
compound_head() with one.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_metapage.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index f03e217ec1cb..c88a7bc3f736 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -689,9 +689,8 @@ void grab_metapage(struct metapage * mp)
 	unlock_page(mp->page);
 }
 
-static int metapage_write_one(struct page *page)
+static int metapage_write_one(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	struct address_space *mapping = folio->mapping;
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_ALL,
@@ -720,17 +719,17 @@ static int metapage_write_one(struct page *page)
 
 void force_metapage(struct metapage *mp)
 {
-	struct page *page = mp->page;
+	struct folio *folio = page_folio(mp->page);
 	jfs_info("force_metapage: mp = 0x%p", mp);
 	set_bit(META_forcewrite, &mp->flag);
 	clear_bit(META_sync, &mp->flag);
-	get_page(page);
-	lock_page(page);
-	set_page_dirty(page);
-	if (metapage_write_one(page))
+	folio_get(folio);
+	folio_lock(folio);
+	folio_mark_dirty(folio);
+	if (metapage_write_one(folio))
 		jfs_error(mp->sb, "metapage_write_one() failed\n");
 	clear_bit(META_forcewrite, &mp->flag);
-	put_page(page);
+	folio_put(folio);
 }
 
 void hold_metapage(struct metapage *mp)
@@ -771,7 +770,7 @@ void release_metapage(struct metapage * mp)
 		folio_mark_dirty(folio);
 		if (test_bit(META_sync, &mp->flag)) {
 			clear_bit(META_sync, &mp->flag);
-			if (metapage_write_one(&folio->page))
+			if (metapage_write_one(folio))
 				jfs_error(mp->sb, "metapage_write_one() failed\n");
 			folio_lock(folio);
 		}
-- 
2.43.0

[PATCH v2 12/13] jfs: Change metapage->page to metapage->folio

[Matthew Wilcox (Oracle)]

Convert all the users to operate on a folio.  Saves sixteen calls to
compound_head().  We still use sizeof(struct page) in print_hex_dump,
otherwise it will go into the second and third pages of the folio which
won't exist for jfs folios (since they are not large).  This needs a
better solution, but finding it can be postponed.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/jfs/jfs_logmgr.c   |  2 +-
 fs/jfs/jfs_metapage.c | 26 +++++++++++++-------------
 fs/jfs/jfs_metapage.h | 16 ++++++++--------
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 9609349e92e5..270808b6219b 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1600,7 +1600,7 @@ void jfs_flush_journal(struct jfs_log *log, int wait)
 					       mp, sizeof(struct metapage), 0);
 				print_hex_dump(KERN_ERR, "page: ",
 					       DUMP_PREFIX_ADDRESS, 16,
-					       sizeof(long), mp->page,
+					       sizeof(long), mp->folio,
 					       sizeof(struct page), 0);
 			} else
 				print_hex_dump(KERN_ERR, "tblock:",
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index c88a7bc3f736..19854bd8dfea 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -47,9 +47,9 @@ static inline void __lock_metapage(struct metapage *mp)
 	do {
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		if (metapage_locked(mp)) {
-			unlock_page(mp->page);
+			folio_unlock(mp->folio);
 			io_schedule();
-			lock_page(mp->page);
+			folio_lock(mp->folio);
 		}
 	} while (trylock_metapage(mp));
 	__set_current_state(TASK_RUNNING);
@@ -57,7 +57,7 @@ static inline void __lock_metapage(struct metapage *mp)
 }
 
 /*
- * Must have mp->page locked
+ * Must have mp->folio locked
  */
 static inline void lock_metapage(struct metapage *mp)
 {
@@ -649,7 +649,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		mp = alloc_metapage(GFP_NOFS);
 		if (!mp)
 			goto unlock;
-		mp->page = &folio->page;
+		mp->folio = folio;
 		mp->sb = inode->i_sb;
 		mp->flag = 0;
 		mp->xflag = COMMIT_PAGE;
@@ -682,11 +682,11 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 void grab_metapage(struct metapage * mp)
 {
 	jfs_info("grab_metapage: mp = 0x%p", mp);
-	get_page(mp->page);
-	lock_page(mp->page);
+	folio_get(mp->folio);
+	folio_lock(mp->folio);
 	mp->count++;
 	lock_metapage(mp);
-	unlock_page(mp->page);
+	folio_unlock(mp->folio);
 }
 
 static int metapage_write_one(struct folio *folio)
@@ -719,7 +719,7 @@ static int metapage_write_one(struct folio *folio)
 
 void force_metapage(struct metapage *mp)
 {
-	struct folio *folio = page_folio(mp->page);
+	struct folio *folio = mp->folio;
 	jfs_info("force_metapage: mp = 0x%p", mp);
 	set_bit(META_forcewrite, &mp->flag);
 	clear_bit(META_sync, &mp->flag);
@@ -734,26 +734,26 @@ void force_metapage(struct metapage *mp)
 
 void hold_metapage(struct metapage *mp)
 {
-	lock_page(mp->page);
+	folio_lock(mp->folio);
 }
 
 void put_metapage(struct metapage *mp)
 {
 	if (mp->count || mp->nohomeok) {
 		/* Someone else will release this */
-		unlock_page(mp->page);
+		folio_unlock(mp->folio);
 		return;
 	}
-	get_page(mp->page);
+	folio_get(mp->folio);
 	mp->count++;
 	lock_metapage(mp);
-	unlock_page(mp->page);
+	folio_unlock(mp->folio);
 	release_metapage(mp);
 }
 
 void release_metapage(struct metapage * mp)
 {
-	struct folio *folio = page_folio(mp->page);
+	struct folio *folio = mp->folio;
 	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 
 	folio_lock(folio);
diff --git a/fs/jfs/jfs_metapage.h b/fs/jfs/jfs_metapage.h
index 4179f9df4deb..2e5015c2705b 100644
--- a/fs/jfs/jfs_metapage.h
+++ b/fs/jfs/jfs_metapage.h
@@ -24,7 +24,7 @@ struct metapage {
 	wait_queue_head_t wait;
 
 	/* implementation */
-	struct page *page;
+	struct folio *folio;
 	struct super_block *sb;
 	unsigned int logical_size;
 
@@ -90,14 +90,14 @@ static inline void discard_metapage(struct metapage *mp)
 
 static inline void metapage_nohomeok(struct metapage *mp)
 {
-	struct page *page = mp->page;
-	lock_page(page);
+	struct folio *folio = mp->folio;
+	folio_lock(folio);
 	if (!mp->nohomeok++) {
 		mark_metapage_dirty(mp);
-		get_page(page);
-		wait_on_page_writeback(page);
+		folio_get(folio);
+		folio_wait_writeback(folio);
 	}
-	unlock_page(page);
+	folio_unlock(folio);
 }
 
 /*
@@ -107,7 +107,7 @@ static inline void metapage_nohomeok(struct metapage *mp)
 static inline void metapage_wait_for_io(struct metapage *mp)
 {
 	if (test_bit(META_io, &mp->flag))
-		wait_on_page_writeback(mp->page);
+		folio_wait_writeback(mp->folio);
 }
 
 /*
@@ -116,7 +116,7 @@ static inline void metapage_wait_for_io(struct metapage *mp)
 static inline void _metapage_homeok(struct metapage *mp)
 {
 	if (!--mp->nohomeok)
-		put_page(mp->page);
+		folio_put(mp->folio);
 }
 
 static inline void metapage_homeok(struct metapage *mp)
-- 
2.43.0

[PATCH v2 13/13] fs: Remove i_blocks_per_page

[Matthew Wilcox (Oracle)]

The last caller has been converted to i_blocks_per_folio() so we
can remove this wrapper.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/pagemap.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e7222433a537..6b2bdaf27bbc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1540,10 +1540,4 @@ unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
 {
 	return folio_size(folio) >> inode->i_blkbits;
 }
-
-static inline
-unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
-{
-	return i_blocks_per_folio(inode, page_folio(page));
-}
 #endif /* _LINUX_PAGEMAP_H */
-- 
2.43.0

[PATCH v2 14/13] jfs: Stop using PG_error

[Matthew Wilcox]

Jan pointed out that I'm really close to being able to remove PG_error
entirely with just jfs and btrfs still testing the flag.  So here's an
attempt to remove use of the PG_error from JFS.  We only need to
remember the 'status' if we have multiple metapage blocks per host page,
so I keep it in the meta_anchor.

What do you think?

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 19854bd8dfea..df575a873ec6 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -76,6 +76,7 @@ static mempool_t *metapage_mempool;
 struct meta_anchor {
 	int mp_count;
 	atomic_t io_count;
+	blk_status_t status;
 	struct metapage *mp[MPS_PER_PAGE];
 };
 
@@ -138,12 +139,16 @@ static inline void inc_io(struct folio *folio)
 	atomic_inc(&anchor->io_count);
 }
 
-static inline void dec_io(struct folio *folio, void (*handler) (struct folio *))
+static inline void dec_io(struct folio *folio, blk_status_t status,
+		void (*handler)(struct folio *, blk_status_t))
 {
 	struct meta_anchor *anchor = folio->private;
 
+	if (anchor->status == BLK_STS_OK)
+		anchor->status = status;
+
 	if (atomic_dec_and_test(&anchor->io_count))
-		handler(folio);
+		handler(folio, anchor->status);
 }
 
 #else
@@ -168,7 +173,7 @@ static inline void remove_metapage(struct folio *folio, struct metapage *mp)
 }
 
 #define inc_io(folio) do {} while(0)
-#define dec_io(folio, handler) handler(folio)
+#define dec_io(folio, status, handler) handler(folio, status)
 
 #endif
 
@@ -258,23 +263,20 @@ static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
 	return lblock;
 }
 
-static void last_read_complete(struct folio *folio)
+static void last_read_complete(struct folio *folio, blk_status_t status)
 {
-	if (!folio_test_error(folio))
-		folio_mark_uptodate(folio);
-	folio_unlock(folio);
+	if (status)
+		printk(KERN_ERR "Read error %d at %#llx\n", status,
+				folio_pos(folio));
+
+	folio_end_read(folio, status == 0);
 }
 
 static void metapage_read_end_io(struct bio *bio)
 {
 	struct folio *folio = bio->bi_private;
 
-	if (bio->bi_status) {
-		printk(KERN_ERR "metapage_read_end_io: I/O error\n");
-		folio_set_error(folio);
-	}
-
-	dec_io(folio, last_read_complete);
+	dec_io(folio, bio->bi_status, last_read_complete);
 	bio_put(bio);
 }
 
@@ -300,11 +302,17 @@ static void remove_from_logsync(struct metapage *mp)
 	LOGSYNC_UNLOCK(log, flags);
 }
 
-static void last_write_complete(struct folio *folio)
+static void last_write_complete(struct folio *folio, blk_status_t status)
 {
 	struct metapage *mp;
 	unsigned int offset;
 
+	if (status) {
+		int err = blk_status_to_errno(status);
+		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
+		mapping_set_error(folio->mapping, err);
+	}
+
 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
 		mp = folio_to_mp(folio, offset);
 		if (mp && test_bit(META_io, &mp->flag)) {
@@ -326,12 +334,7 @@ static void metapage_write_end_io(struct bio *bio)
 
 	BUG_ON(!folio->private);
 
-	if (bio->bi_status) {
-		int err = blk_status_to_errno(bio->bi_status);
-		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
-		mapping_set_error(folio->mapping, err);
-	}
-	dec_io(folio, last_write_complete);
+	dec_io(folio, bio->bi_status, last_write_complete);
 	bio_put(bio);
 }
 
@@ -454,10 +457,10 @@ static int metapage_write_folio(struct folio *folio,
 		       4, bio, sizeof(*bio), 0);
 	bio_put(bio);
 	folio_unlock(folio);
-	dec_io(folio, last_write_complete);
+	dec_io(folio, BLK_STS_OK, last_write_complete);
 err_out:
 	while (bad_blocks--)
-		dec_io(folio, last_write_complete);
+		dec_io(folio, BLK_STS_OK, last_write_complete);
 	return -EIO;
 }
 

Re: [PATCH v2 00/13] JFS folio conversion

[Dave Kleikamp]

On 4/17/24 12:56PM, Matthew Wilcox (Oracle) wrote:
> This patchset removes uses of struct page from the I/O paths of JFS.
> write_begin and write_end are still passed a struct page, but they convert
> to a folio as their first thing.  The logmgr still uses a struct page,
> but I think that's one we actually don't want to convert since it's
> never inserted into the page cache.
> 
> I've included the removal of i_blocks_per_page() in this series as JFS
> is the last user.
> 
> Tested with xfstests; some failures observed, but they don't seem to be
> related to these patches.  I haven't tried with PAGE_SIZE > 4kB, so the
> MPS_PER_PAGE > 1 paths are untested.

These patches look good to me. I'm pushing to linux-next. I'm sorry I 
didn't get them reviewed in time for the 6.10 merge window, but I'll 
target 6.11.

Shaggy

> 
> v2:
>   - Fix build errors on machines with PAGE_SIZE > 4096
> 
> Matthew Wilcox (Oracle) (13):
>    jfs: Convert metapage_read_folio to use folio APIs
>    jfs: Convert metapage_writepage to metapage_write_folio
>    jfs: Convert __get_metapage to use a folio
>    jfs: Convert insert_metapage() to take a folio
>    jfs; Convert release_metapage to use a folio
>    jfs: Convert drop_metapage and remove_metapage to take a folio
>    jfs: Convert dec_io to take a folio
>    jfs; Convert __invalidate_metapages to use a folio
>    jfs: Convert page_to_mp to folio_to_mp
>    jfs: Convert inc_io to take a folio
>    jfs: Convert force_metapage to use a folio
>    jfs: Change metapage->page to metapage->folio
>    fs: Remove i_blocks_per_page
> 
>   fs/jfs/jfs_logmgr.c     |   2 +-
>   fs/jfs/jfs_metapage.c   | 299 ++++++++++++++++++++--------------------
>   fs/jfs/jfs_metapage.h   |  16 +--
>   include/linux/pagemap.h |   6 -
>   4 files changed, 156 insertions(+), 167 deletions(-)
>