[PATCH v2 01/14] f2fs: extend folio state for large folio write path
From: Nanzhe Zhao
Date: Tue Sep 15 2026 - 00:20:18 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/data.c | 72 ++++++++++++++++++++++++++++++++------------------
fs/f2fs/f2fs.h | 70 +++++++++++++++++++++++++++++++++++-------------
2 files changed, 98 insertions(+), 44 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index a3b02c067e89..b3303109a696 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -32,15 +32,9 @@
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;
@@ -125,6 +119,9 @@ struct bio_post_read_ctx {
block_t fs_blkaddr;
};
+static bool __ffs_mark_subrange_uptodate(struct folio *folio,
+ struct f2fs_folio_state *ffs, size_t offset, size_t len);
+
/*
* Update and unlock a bio's pages, and free the bio.
*
@@ -139,6 +136,23 @@ struct bio_post_read_ctx {
* called (i.e., I/O error or decryption error, but *not* verity error), and
* release the bio's reference to the decompress_io_ctx of the page's cluster.
*/
+/*
+ * Update read_pages_pending.
+ */
+static inline void f2fs_update_read_folio_pending(struct folio *folio, int nr)
+{
+ struct f2fs_folio_state *ffs;
+ unsigned long flags;
+
+ if (!f2fs_folio_has_ffs(folio))
+ return;
+
+ ffs = (struct f2fs_folio_state *)folio->private;
+ spin_lock_irqsave(&ffs->state_lock, flags);
+ ffs->read_pages_pending += nr;
+ spin_unlock_irqrestore(&ffs->state_lock, flags);
+}
+
static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
{
struct folio_iter fi;
@@ -147,7 +161,7 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
bio_for_each_folio_all(fi, bio) {
struct folio *folio = fi.folio;
- unsigned nr_pages = fi.length >> PAGE_SHIFT;
+ unsigned int nr_pages = fi.length >> PAGE_SHIFT;
bool finished = true;
if (!folio_test_large(folio) &&
@@ -2487,17 +2501,31 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
}
#endif
-static struct f2fs_folio_state *ffs_find_or_alloc(struct folio *folio)
+struct f2fs_folio_state *f2fs_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 = (unsigned long)folio->private;
+
+ f2fs_bug_on(F2FS_F_SB(folio), !folio_test_large(folio));
+ f2fs_bug_on(F2FS_F_SB(folio),
+ test_bit(PAGE_PRIVATE_NOT_POINTER, &private));
- if (ffs)
- return ffs;
+ if (f2fs_folio_has_ffs(folio))
+ return (struct f2fs_folio_state *)folio->private;
- ffs = f2fs_kmem_cache_alloc(ffs_entry_slab,
- GFP_NOIO | __GFP_ZERO, true, NULL);
+ ffs = f2fs_kmalloc(F2FS_F_SB(folio),
+ struct_size(ffs, state, BITS_TO_LONGS(2 * nr_subpages)),
+ GFP_NOFS | __GFP_ZERO);
+ if (!ffs)
+ return NULL;
spin_lock_init(&ffs->state_lock);
+ 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);
+
folio_attach_private(folio, ffs);
return ffs;
}
@@ -2506,7 +2534,7 @@ static void ffs_detach_free(struct folio *folio)
{
struct f2fs_folio_state *ffs;
- if (!folio_test_large(folio)) {
+ if (!f2fs_folio_has_ffs(folio)) {
folio_detach_private(folio);
return;
}
@@ -2516,7 +2544,8 @@ 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,
@@ -2529,7 +2558,7 @@ static int f2fs_read_data_large_folio(struct inode *inode,
pgoff_t index, offset, next_pgofs = 0;
unsigned max_nr_pages = rac ? readahead_count(rac) :
folio_nr_pages(folio);
- unsigned nrpages;
+ unsigned int nrpages;
struct f2fs_folio_state *ffs;
int ret = 0;
bool folio_in_bio = false;
@@ -2605,7 +2634,7 @@ static int f2fs_read_data_large_folio(struct inode *inode,
* to prevent from premature folio_end_read() call on folio
*/
if (folio_test_large(folio)) {
- ffs = ffs_find_or_alloc(folio);
+ ffs = f2fs_ffs_find_or_alloc(folio);
/* set the bitmap to wait */
spin_lock_irq(&ffs->state_lock);
@@ -4522,21 +4551,12 @@ 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 ebc621f302e1..9a2366a6c113 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1618,6 +1618,18 @@ 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;
+ /* state[0..nr_subpages - 1] tracks uptodate subpages.
+ * state[nr_subpages..2 * nr_subpages - 1] tracks dirty subpages.
+ */
+ unsigned long state[];
+};
+
enum {
PAGE_PRIVATE_NOT_POINTER, /* private contains non-pointer data */
PAGE_PRIVATE_ONGOING_MIGRATION, /* data page which is on-going migrating */
@@ -1627,6 +1639,13 @@ enum {
PAGE_PRIVATE_MAX
};
+static inline bool f2fs_folio_has_ffs(const struct folio *folio)
+{
+ unsigned long private = (unsigned long)folio->private;
+
+ return folio_test_large(folio) && private;
+}
+
/* For compression */
enum compress_algorithm_type {
COMPRESS_LZO,
@@ -2738,13 +2757,35 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
return -ENOSPC;
}
+static inline unsigned long f2fs_folio_get_private_flags(const struct folio *folio)
+{
+ unsigned long private = (unsigned long)folio->private;
+
+ if (f2fs_folio_has_ffs(folio)) {
+ struct f2fs_folio_state *ffs = (struct f2fs_folio_state *)private;
+
+ return READ_ONCE(ffs->private_flags);
+ }
+
+ if (test_bit(PAGE_PRIVATE_NOT_POINTER, &private))
+ return private;
+
+ return 0;
+}
+
+static inline unsigned long *f2fs_folio_flags_addr(struct folio *folio)
+{
+ if (f2fs_folio_has_ffs(folio))
+ return &((struct f2fs_folio_state *)folio->private)->private_flags;
+
+ return (unsigned long *)&folio->private;
+}
+
#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 v = (1UL << PAGE_PRIVATE_NOT_POINTER) | \
- (1UL << PAGE_PRIVATE_##flagname); \
- return (priv & v) == v; \
+ return f2fs_folio_get_private_flags(folio) & \
+ (1UL << PAGE_PRIVATE_##flagname); \
} \
static inline bool page_private_##name(struct page *page) \
{ \
@@ -2756,14 +2797,10 @@ static inline bool page_private_##name(struct page *page) \
#define PAGE_PRIVATE_SET_FUNC(name, flagname) \
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) \
- folio_attach_private(folio, (void *)v); \
- else { \
- v |= (unsigned long)folio->private; \
- folio->private = (void *)v; \
- } \
+ folio_attach_private(folio, \
+ (void *)BIT(PAGE_PRIVATE_NOT_POINTER)); \
+ set_bit(PAGE_PRIVATE_##flagname, f2fs_folio_flags_addr(folio)); \
} \
static inline void set_page_private_##name(struct page *page) \
{ \
@@ -2776,13 +2813,10 @@ 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; \
- \
- v &= ~(1UL << PAGE_PRIVATE_##flagname); \
- if (v == (1UL << PAGE_PRIVATE_NOT_POINTER)) \
+ clear_bit(PAGE_PRIVATE_##flagname, \
+ f2fs_folio_flags_addr(folio)); \
+ if (folio->private == (void *)BIT(PAGE_PRIVATE_NOT_POINTER)) \
folio_detach_private(folio); \
- else \
- folio->private = (void *)v; \
} \
static inline void clear_page_private_##name(struct page *page) \
{ \
@@ -2808,7 +2842,7 @@ 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 = f2fs_folio_get_private_flags(folio);
if (!test_bit(PAGE_PRIVATE_NOT_POINTER, &data))
return 0;
--
2.43.0