FAILED: patch "[PATCH] f2fs: remove mappedtodisk flag usage in mmap write path" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] f2fs: remove mappedtodisk flag usage in mmap write path" failed to apply to 6.6-stable tree

[Sasha Levin]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x b3c9843589257631bac18f30655e82d88970688a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053437-failed-6.6-b3c984358925@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From b3c9843589257631bac18f30655e82d88970688a Mon Sep 17 00:00:00 2001
From: Nanzhe Zhao <zhaonanzhe@xiaomi.com>
Date: Mon, 12 Oct 2026 11:03:15 +0800
Subject: [PATCH] f2fs: remove mappedtodisk flag usage in mmap write path

PG_mappedtodisk was inherited from the nobh/buffer-head era.  However,
f2fs has no buffer heads and the flag is no longer meaningful.  The only
user of the flag is the "no holes" shortcut in f2fs_vm_page_mkwrite(),
which makes mmap write faults skip marking the folio dirty.  Moreover,
it causes the following race condition with filesystem freezing:

 CPU0 (write fault)     CPU1 (freeze_super)
 ----                   ----
 f2fs_vm_page_mkwrite()
 sb_start_pagefault()
 /* shortcut: no dirty */
 sb_end_pagefault()

                        sb_wait_write(SB_FREEZE_PAGEFAULT)
                        /* no waiter, passes */
                        sync_filesystem()
                        /* folio not dirty, skipped */

 finish_fault()
 /* PTE writable */
 fault_dirty_shared_page()
 folio_mark_dirty()
 /* dirty folio on a frozen fs */

It will also skip APP_MAPPED_IO iostat/REQ_TIME updates and post-EOF
folio zeroing.

Remove this shortcut in f2fs_vm_page_mkwrite() and stop setting it in
f2fs_read_single_page().

Reported-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/linux-f2fs-devel/496b913c-eb81-4fa8-be72-c6a06a10aba2@kernel.org/
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Fixes: fbfa2cc58d53 ("f2fs: add file operations")
Cc: stable@vger.kernel.org
Signed-off-by: Nanzhe Zhao <zhaonanzhe@xiaomi.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/data.c | 1 -
 fs/f2fs/file.c | 6 ------
 2 files changed, 7 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 2613e8821af6d..348ddc8b748c5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2494,7 +2494,6 @@ static int f2fs_read_single_page(struct inode *inode, struct fsverity_info *vi,
 got_it:
 	if ((map->m_flags & F2FS_MAP_MAPPED)) {
 		block_nr = map->m_pblk + block_in_file - map->m_lblk;
-		folio_set_mappedtodisk(folio);
 
 		if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr,
 						DATA_GENERIC_ENHANCE_READ)) {
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index ef4d218e694bd..4363e28056e6b 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -218,12 +218,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 	/* wait for GCed page writeback via generic cache */
 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 
-	/*
-	 * check to see if the page is mapped already (no holes)
-	 */
-	if (folio_test_mappedtodisk(folio))
-		goto out_sem;
-
 	/* page is wholly or partially inside EOF */
 	if (((loff_t)(folio->index + 1) << PAGE_SHIFT) >
 						i_size_read(inode)) {
-- 
2.53.0

[PATCH 6.6.y 1/3] f2fs: convert f2fs_mpage_readpages() to use folio

[Sasha Levin]

From: Chao Yu <chao@kernel.org>

[ Upstream commit db92e6c729d87e6f5b0f467f01a96dbf1e452106 ]

Convert f2fs_mpage_readpages() to use folio and related
functionality.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Stable-dep-of: b3c984358925 ("f2fs: remove mappedtodisk flag usage in mmap write path")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/data.c | 80 +++++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 40 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b0c633c5deb75..3cb822e799be8 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2375,7 +2375,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
  * Major change was from block_size == page_size in f2fs by default.
  */
 static int f2fs_mpage_readpages(struct inode *inode,
-		struct readahead_control *rac, struct page *page)
+		struct readahead_control *rac, struct folio *folio)
 {
 	struct bio *bio = NULL;
 	sector_t last_block_in_bio = 0;
@@ -2395,6 +2395,7 @@ static int f2fs_mpage_readpages(struct inode *inode,
 #endif
 	unsigned nr_pages = rac ? readahead_count(rac) : 1;
 	unsigned max_nr_pages = nr_pages;
+	pgoff_t index;
 	int ret = 0;
 
 	map.m_pblk = 0;
@@ -2408,64 +2409,63 @@ static int f2fs_mpage_readpages(struct inode *inode,
 
 	for (; nr_pages; nr_pages--) {
 		if (rac) {
-			page = readahead_page(rac);
-			prefetchw(&page->flags);
+			folio = readahead_folio(rac);
+			prefetchw(&folio->flags);
 		}
 
-#ifdef CONFIG_F2FS_FS_COMPRESSION
-		if (f2fs_compressed_file(inode)) {
-			/* there are remained compressed pages, submit them */
-			if (!f2fs_cluster_can_merge_page(&cc, page->index)) {
-				ret = f2fs_read_multi_pages(&cc, &bio,
-							max_nr_pages,
-							&last_block_in_bio,
-							rac != NULL, false);
-				f2fs_destroy_compress_ctx(&cc, false);
-				if (ret)
-					goto set_error_page;
-			}
-			if (cc.cluster_idx == NULL_CLUSTER) {
-				if (nc_cluster_idx ==
-					page->index >> cc.log_cluster_size) {
-					goto read_single_page;
-				}
-
-				ret = f2fs_is_compressed_cluster(inode, page->index);
-				if (ret < 0)
-					goto set_error_page;
-				else if (!ret) {
-					nc_cluster_idx =
-						page->index >> cc.log_cluster_size;
-					goto read_single_page;
-				}
+		index = folio_index(folio);
 
-				nc_cluster_idx = NULL_CLUSTER;
-			}
-			ret = f2fs_init_compress_ctx(&cc);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+		if (!f2fs_compressed_file(inode))
+			goto read_single_page;
+
+		/* there are remained compressed pages, submit them */
+		if (!f2fs_cluster_can_merge_page(&cc, index)) {
+			ret = f2fs_read_multi_pages(&cc, &bio,
+						max_nr_pages,
+						&last_block_in_bio,
+						rac != NULL, false);
+			f2fs_destroy_compress_ctx(&cc, false);
 			if (ret)
 				goto set_error_page;
+		}
+		if (cc.cluster_idx == NULL_CLUSTER) {
+			if (nc_cluster_idx == index >> cc.log_cluster_size)
+				goto read_single_page;
 
-			f2fs_compress_ctx_add_page(&cc, page);
+			ret = f2fs_is_compressed_cluster(inode, index);
+			if (ret < 0)
+				goto set_error_page;
+			else if (!ret) {
+				nc_cluster_idx =
+					index >> cc.log_cluster_size;
+				goto read_single_page;
+			}
 
-			goto next_page;
+			nc_cluster_idx = NULL_CLUSTER;
 		}
+		ret = f2fs_init_compress_ctx(&cc);
+		if (ret)
+			goto set_error_page;
+
+		f2fs_compress_ctx_add_page(&cc, &folio->page);
+
+		goto next_page;
 read_single_page:
 #endif
 
-		ret = f2fs_read_single_page(inode, page, max_nr_pages, &map,
+		ret = f2fs_read_single_page(inode, &folio->page, max_nr_pages, &map,
 					&bio, &last_block_in_bio, rac);
 		if (ret) {
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 set_error_page:
 #endif
-			zero_user_segment(page, 0, PAGE_SIZE);
-			unlock_page(page);
+			folio_zero_segment(folio, 0, folio_size(folio));
+			folio_unlock(folio);
 		}
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 next_page:
 #endif
-		if (rac)
-			put_page(page);
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 		if (f2fs_compressed_file(inode)) {
@@ -2502,7 +2502,7 @@ static int f2fs_read_data_folio(struct file *file, struct folio *folio)
 	if (f2fs_has_inline_data(inode))
 		ret = f2fs_read_inline_data(inode, page);
 	if (ret == -EAGAIN)
-		ret = f2fs_mpage_readpages(inode, NULL, page);
+		ret = f2fs_mpage_readpages(inode, NULL, folio);
 	return ret;
 }
 
-- 
2.53.0

[PATCH 6.6.y 2/3] f2fs: convert f2fs_read_single_page() to use folio

[Sasha Levin]

From: Chao Yu <chao@kernel.org>

[ Upstream commit ed54eed355675f79d9322c07d92f38037fc6b514 ]

Convert f2fs_read_single_page() to use folio and related
functionality.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Stable-dep-of: b3c984358925 ("f2fs: remove mappedtodisk flag usage in mmap write path")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/data.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3cb822e799be8..e1c66f64aff38 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2089,7 +2089,7 @@ static inline loff_t f2fs_readpage_limit(struct inode *inode)
 	return i_size_read(inode);
 }
 
-static int f2fs_read_single_page(struct inode *inode, struct page *page,
+static int f2fs_read_single_page(struct inode *inode, struct folio *folio,
 					unsigned nr_pages,
 					struct f2fs_map_blocks *map,
 					struct bio **bio_ret,
@@ -2102,9 +2102,10 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 	sector_t last_block;
 	sector_t last_block_in_file;
 	sector_t block_nr;
+	pgoff_t index = folio_index(folio);
 	int ret = 0;
 
-	block_in_file = (sector_t)page_index(page);
+	block_in_file = (sector_t)index;
 	last_block = block_in_file + nr_pages;
 	last_block_in_file = bytes_to_blks(inode,
 			f2fs_readpage_limit(inode) + blocksize - 1);
@@ -2135,7 +2136,7 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 got_it:
 	if ((map->m_flags & F2FS_MAP_MAPPED)) {
 		block_nr = map->m_pblk + block_in_file - map->m_lblk;
-		SetPageMappedToDisk(page);
+		folio_set_mappedtodisk(folio);
 
 		if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr,
 						DATA_GENERIC_ENHANCE_READ)) {
@@ -2146,15 +2147,15 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 		}
 	} else {
 zero_out:
-		zero_user_segment(page, 0, PAGE_SIZE);
-		if (f2fs_need_verity(inode, page->index) &&
-		    !fsverity_verify_page(page)) {
+		folio_zero_segment(folio, 0, folio_size(folio));
+		if (f2fs_need_verity(inode, index) &&
+		    !fsverity_verify_folio(folio)) {
 			ret = -EIO;
 			goto out;
 		}
-		if (!PageUptodate(page))
-			SetPageUptodate(page);
-		unlock_page(page);
+		if (!folio_test_uptodate(folio))
+			folio_mark_uptodate(folio);
+		folio_unlock(folio);
 		goto out;
 	}
 
@@ -2164,14 +2165,14 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 	 */
 	if (bio && (!page_is_mergeable(F2FS_I_SB(inode), bio,
 				       *last_block_in_bio, block_nr) ||
-		    !f2fs_crypt_mergeable_bio(bio, inode, page->index, NULL))) {
+		    !f2fs_crypt_mergeable_bio(bio, inode, index, NULL))) {
 submit_and_realloc:
 		f2fs_submit_read_bio(F2FS_I_SB(inode), bio, DATA);
 		bio = NULL;
 	}
 	if (bio == NULL) {
 		bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
-				is_readahead ? REQ_RAHEAD : 0, page->index,
+				is_readahead ? REQ_RAHEAD : 0, index,
 				false);
 		if (IS_ERR(bio)) {
 			ret = PTR_ERR(bio);
@@ -2186,7 +2187,7 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 	 */
 	f2fs_wait_on_block_writeback(inode, block_nr);
 
-	if (bio_add_page(bio, page, blocksize, 0) < blocksize)
+	if (!bio_add_folio(bio, folio, blocksize, 0))
 		goto submit_and_realloc;
 
 	inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
@@ -2454,7 +2455,7 @@ static int f2fs_mpage_readpages(struct inode *inode,
 read_single_page:
 #endif
 
-		ret = f2fs_read_single_page(inode, &folio->page, max_nr_pages, &map,
+		ret = f2fs_read_single_page(inode, folio, max_nr_pages, &map,
 					&bio, &last_block_in_bio, rac);
 		if (ret) {
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-- 
2.53.0

[PATCH 6.6.y 3/3] f2fs: remove mappedtodisk flag usage in mmap write path

[Sasha Levin]

From: Nanzhe Zhao <zhaonanzhe@xiaomi.com>

[ Upstream commit b3c9843589257631bac18f30655e82d88970688a ]

PG_mappedtodisk was inherited from the nobh/buffer-head era.  However,
f2fs has no buffer heads and the flag is no longer meaningful.  The only
user of the flag is the "no holes" shortcut in f2fs_vm_page_mkwrite(),
which makes mmap write faults skip marking the folio dirty.  Moreover,
it causes the following race condition with filesystem freezing:

 CPU0 (write fault)     CPU1 (freeze_super)
 ----                   ----
 f2fs_vm_page_mkwrite()
 sb_start_pagefault()
 /* shortcut: no dirty */
 sb_end_pagefault()

                        sb_wait_write(SB_FREEZE_PAGEFAULT)
                        /* no waiter, passes */
                        sync_filesystem()
                        /* folio not dirty, skipped */

 finish_fault()
 /* PTE writable */
 fault_dirty_shared_page()
 folio_mark_dirty()
 /* dirty folio on a frozen fs */

It will also skip APP_MAPPED_IO iostat/REQ_TIME updates and post-EOF
folio zeroing.

Remove this shortcut in f2fs_vm_page_mkwrite() and stop setting it in
f2fs_read_single_page().

Reported-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/linux-f2fs-devel/496b913c-eb81-4fa8-be72-c6a06a10aba2@kernel.org/
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Fixes: fbfa2cc58d53 ("f2fs: add file operations")
Cc: stable@vger.kernel.org
Signed-off-by: Nanzhe Zhao <zhaonanzhe@xiaomi.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/data.c | 1 -
 fs/f2fs/file.c | 6 ------
 2 files changed, 7 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e1c66f64aff38..288de302e83be 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2136,7 +2136,6 @@ static int f2fs_read_single_page(struct inode *inode, struct folio *folio,
 got_it:
 	if ((map->m_flags & F2FS_MAP_MAPPED)) {
 		block_nr = map->m_pblk + block_in_file - map->m_lblk;
-		folio_set_mappedtodisk(folio);
 
 		if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr,
 						DATA_GENERIC_ENHANCE_READ)) {
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7ec8d054bf1ee..f4863d7331802 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -215,12 +215,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 	/* wait for GCed page writeback via META_MAPPING */
 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 
-	/*
-	 * check to see if the page is mapped already (no holes)
-	 */
-	if (folio_test_mappedtodisk(folio))
-		goto out_sem;
-
 	/* page is wholly or partially inside EOF */
 	if (((loff_t)(folio->index + 1) << PAGE_SHIFT) > isize) {
 		loff_t offset;
-- 
2.53.0