[f2fs-dev] [RFC PATCH v2 01/10] f2fs: extend folio state for large folio write path
From: Nanzhe Zhao
Date: Mon Jun 22 2026 - 12:09:30 EST
Large folio write path needs a subpage status bitmap and write
pages pending counter, while keeping compatible with f2fs private
flags.
Move struct f2fs_folio_state to f2fs.h, add private_flags and
subpage state bitmap, and change PAGE_PRIVATE functions to be
compatible with f2fs_folio_state. Allocate f2fs_folio_state via kzalloc
instead of kmem_cache, since the state size depends on the folio order.
Note: Now if a path wants to use f2fs_folio_state, it must call
`folio_has_ffs` instead of `folio_test_large`` to make check.
Signed-off-by: Nanzhe Zhao <zhaonanzhe@xxxxxxxxxx>
---
fs/f2fs/compress.c | 2 ++
fs/f2fs/data.c | 46 ++++++++++++++++----------------
fs/f2fs/f2fs.h | 66 ++++++++++++++++++++++++++++++++++++++--------
3 files changed, 80 insertions(+), 34 deletions(-)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 91855d91bbdd..de1305fcc6c1 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -76,6 +76,8 @@ bool f2fs_is_compressed_page(struct folio *folio)
{
if (!folio->private)
return false;
+ if (folio_has_ffs(folio))
+ return false;
if (folio_test_f2fs_nonpointer(folio))
return false;
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index ac1cf4de3d62..23758c00758d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -32,20 +32,13 @@
static struct kmem_cache *bio_post_read_ctx_cache;
static struct kmem_cache *bio_entry_slab;
-static struct kmem_cache *ffs_entry_slab;
static mempool_t *bio_post_read_ctx_pool;
static struct bio_set f2fs_bioset;
-struct f2fs_folio_state {
- spinlock_t state_lock;
- unsigned int read_pages_pending;
-};
-
struct f2fs_bio {
struct work_struct work;
struct bio bio;
};
-
#define F2FS_BIO_POOL_SIZE NR_CURSEG_TYPE
int __init f2fs_init_bioset(void)
@@ -2514,15 +2507,30 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
static struct f2fs_folio_state *ffs_find_or_alloc(struct folio *folio)
{
- struct f2fs_folio_state *ffs = folio->private;
+ struct f2fs_folio_state *ffs;
+ unsigned int nr_subpages = folio_nr_pages(folio);
+ unsigned long private_flags = 0;
- if (ffs)
- return ffs;
+ f2fs_bug_on(F2FS_F_SB(folio), !folio_test_large(folio));
- ffs = f2fs_kmem_cache_alloc(ffs_entry_slab,
- GFP_NOIO | __GFP_ZERO, true, NULL);
+ if (folio_has_ffs(folio))
+ return (struct f2fs_folio_state *)folio->private;
+
+ if (folio_test_private(folio) && folio_test_f2fs_nonpointer(folio))
+ private_flags = (unsigned long)folio->private;
+
+ ffs = kzalloc(struct_size(ffs, state, BITS_TO_LONGS(2 * nr_subpages)),
+ GFP_NOIO | __GFP_NOFAIL);
spin_lock_init(&ffs->state_lock);
+ ffs->private_flags = private_flags;
+ if (folio_test_uptodate(folio))
+ bitmap_set(ffs->state, 0, nr_subpages);
+ if (folio_test_dirty(folio))
+ bitmap_set(ffs->state, nr_subpages, nr_subpages);
+
+ if (folio_test_private(folio))
+ folio_detach_private(folio);
folio_attach_private(folio, ffs);
return ffs;
}
@@ -2531,7 +2539,7 @@ static void ffs_detach_free(struct folio *folio)
{
struct f2fs_folio_state *ffs;
- if (!folio_test_large(folio)) {
+ if (!folio_has_ffs(folio)) {
folio_detach_private(folio);
return;
}
@@ -2541,7 +2549,8 @@ static void ffs_detach_free(struct folio *folio)
return;
WARN_ON_ONCE(ffs->read_pages_pending != 0);
- kmem_cache_free(ffs_entry_slab, ffs);
+ WARN_ON_ONCE(atomic_read(&ffs->write_pages_pending));
+ kfree(ffs);
}
static int f2fs_read_data_large_folio(struct inode *inode,
@@ -4571,21 +4580,12 @@ int __init f2fs_init_bio_entry_cache(void)
if (!bio_entry_slab)
return -ENOMEM;
- ffs_entry_slab = f2fs_kmem_cache_create("f2fs_ffs_slab",
- sizeof(struct f2fs_folio_state));
-
- if (!ffs_entry_slab) {
- kmem_cache_destroy(bio_entry_slab);
- return -ENOMEM;
- }
-
return 0;
}
void f2fs_destroy_bio_entry_cache(void)
{
kmem_cache_destroy(bio_entry_slab);
- kmem_cache_destroy(ffs_entry_slab);
}
static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f1774d4e18d2..e4778c17394e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1620,6 +1620,15 @@ static inline void f2fs_clear_bit(unsigned int nr, char *addr);
* Layout B: lowest bit should be 0
* page.private is a wrapped pointer.
*/
+
+struct f2fs_folio_state {
+ spinlock_t state_lock;
+ unsigned int read_pages_pending;
+ atomic_t write_pages_pending;
+ unsigned long private_flags;
+ unsigned long state[];
+};
+
enum {
PAGE_PRIVATE_NOT_POINTER, /* private contains non-pointer data */
PAGE_PRIVATE_ONGOING_MIGRATION, /* data page which is on-going migrating */
@@ -1629,6 +1638,14 @@ enum {
PAGE_PRIVATE_MAX
};
+static inline bool folio_has_ffs(const struct folio *folio)
+{
+ unsigned long private = (unsigned long)folio->private;
+
+ return folio_test_large(folio) && private &&
+ !(private & BIT(PAGE_PRIVATE_NOT_POINTER));
+}
+
/* For compression */
enum compress_algorithm_type {
COMPRESS_LZO,
@@ -2638,9 +2655,15 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
#define PAGE_PRIVATE_GET_FUNC(name, flagname) \
static inline bool folio_test_f2fs_##name(const struct folio *folio) \
{ \
- unsigned long priv = (unsigned long)folio->private; \
+ unsigned long priv; \
unsigned long v = (1UL << PAGE_PRIVATE_NOT_POINTER) | \
(1UL << PAGE_PRIVATE_##flagname); \
+ if (folio_has_ffs(folio)) { \
+ struct f2fs_folio_state *ffs = folio->private; \
+ priv = ffs->private_flags; \
+ } else { \
+ priv = (unsigned long)folio->private; \
+ } \
return (priv & v) == v; \
} \
static inline bool page_private_##name(struct page *page) \
@@ -2655,7 +2678,10 @@ static inline void folio_set_f2fs_##name(struct folio *folio) \
{ \
unsigned long v = (1UL << PAGE_PRIVATE_NOT_POINTER) | \
(1UL << PAGE_PRIVATE_##flagname); \
- if (!folio->private) \
+ if (folio_has_ffs(folio)) { \
+ struct f2fs_folio_state *ffs = folio->private; \
+ ffs->private_flags |= v; \
+ } else if (!folio->private) \
folio_attach_private(folio, (void *)v); \
else { \
v |= (unsigned long)folio->private; \
@@ -2673,13 +2699,18 @@ static inline void set_page_private_##name(struct page *page) \
#define PAGE_PRIVATE_CLEAR_FUNC(name, flagname) \
static inline void folio_clear_f2fs_##name(struct folio *folio) \
{ \
- unsigned long v = (unsigned long)folio->private; \
+ if (folio_has_ffs(folio)) { \
+ struct f2fs_folio_state *ffs = folio->private; \
+ ffs->private_flags &= ~(1UL << PAGE_PRIVATE_##flagname); \
+ } else { \
+ unsigned long v = (unsigned long)folio->private; \
\
- v &= ~(1UL << PAGE_PRIVATE_##flagname); \
- if (v == (1UL << PAGE_PRIVATE_NOT_POINTER)) \
- folio_detach_private(folio); \
- else \
- folio->private = (void *)v; \
+ v &= ~(1UL << PAGE_PRIVATE_##flagname); \
+ if (v == (1UL << PAGE_PRIVATE_NOT_POINTER)) \
+ folio_detach_private(folio); \
+ else \
+ folio->private = (void *)v; \
+ } \
} \
static inline void clear_page_private_##name(struct page *page) \
{ \
@@ -2705,7 +2736,15 @@ PAGE_PRIVATE_CLEAR_FUNC(atomic, ATOMIC_WRITE);
static inline unsigned long folio_get_f2fs_data(struct folio *folio)
{
- unsigned long data = (unsigned long)folio->private;
+ unsigned long data;
+
+ if (folio_has_ffs(folio)) {
+ struct f2fs_folio_state *ffs = folio->private;
+
+ data = ffs->private_flags;
+ } else {
+ data = (unsigned long)folio->private;
+ }
if (!test_bit(PAGE_PRIVATE_NOT_POINTER, &data))
return 0;
@@ -2716,10 +2755,15 @@ static inline void folio_set_f2fs_data(struct folio *folio, unsigned long data)
{
data = (1UL << PAGE_PRIVATE_NOT_POINTER) | (data << PAGE_PRIVATE_MAX);
- if (!folio_test_private(folio))
+ if (folio_has_ffs(folio)) {
+ struct f2fs_folio_state *ffs = folio->private;
+
+ ffs->private_flags |= data;
+ } else if (!folio_test_private(folio)) {
folio_attach_private(folio, (void *)data);
- else
+ } else {
folio->private = (void *)((unsigned long)folio->private | data);
+ }
}
static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,
--
2.34.1