[PATCH v2 4/8] ext4/jbd2: convert jbd2_journal_blocks_per_page() to support large folio

Zhang Yi
2025-05-12T06:44:53Z

From: Zhang Yi <yi.zhang@huawei.com>

jbd2_journal_blocks_per_page() returns the number of blocks in a single
page. Rename it to jbd2_journal_blocks_per_folio() and make it returns
the number of blocks in the largest folio, preparing for the calculation
of journal credits blocks when allocating blocks within a large folio in
the writeback path.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/ext4_jbd2.h | 4 ++--
fs/ext4/inode.c | 6 +++---
fs/jbd2/journal.c | 7 ++++---
include/linux/jbd2.h | 2 +-
4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 3221714d9901..63d17c5201b5 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -319,10 +319,10 @@ static inline int ext4_journal_ensure_credits(handle_t *handle, int credits,
revoke_creds, 0);
}

-static inline int ext4_journal_blocks_per_page(struct inode *inode)
+static inline int ext4_journal_blocks_per_folio(struct inode *inode)
{
if (EXT4_JOURNAL(inode) != NULL)
- return jbd2_journal_blocks_per_page(inode);
+ return jbd2_journal_blocks_per_folio(inode);
return 0;
}

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 573ae0b3be1d..ffbf444b56d4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2361,7 +2361,7 @@ static int mpage_map_and_submit_extent(handle_t *handle,
*/
static int ext4_da_writepages_trans_blocks(struct inode *inode)
{
- int bpp = ext4_journal_blocks_per_page(inode);
+ int bpp = ext4_journal_blocks_per_folio(inode);

return ext4_meta_trans_blocks(inode,
MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
@@ -2439,7 +2439,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
ext4_lblk_t lblk;
struct buffer_head *head;
handle_t *handle = NULL;
- int bpp = ext4_journal_blocks_per_page(mpd->inode);
+ int bpp = ext4_journal_blocks_per_folio(mpd->inode);

if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
@@ -5831,7 +5831,7 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
*/
int ext4_writepage_trans_blocks(struct inode *inode)
{
- int bpp = ext4_journal_blocks_per_page(inode);
+ int bpp = ext4_journal_blocks_per_folio(inode);
int ret;

ret = ext4_meta_trans_blocks(inode, bpp, bpp);
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 743a1d7633cd..ecf31af7d2fb 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -83,7 +83,7 @@ EXPORT_SYMBOL(jbd2_log_wait_commit);
EXPORT_SYMBOL(jbd2_journal_start_commit);
EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
EXPORT_SYMBOL(jbd2_journal_wipe);
-EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
+EXPORT_SYMBOL(jbd2_journal_blocks_per_folio);
EXPORT_SYMBOL(jbd2_journal_invalidate_folio);
EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
EXPORT_SYMBOL(jbd2_journal_force_commit);
@@ -2657,9 +2657,10 @@ void jbd2_journal_ack_err(journal_t *journal)
write_unlock(&journal->j_state_lock);
}

-int jbd2_journal_blocks_per_page(struct inode *inode)
+int jbd2_journal_blocks_per_folio(struct inode *inode)
{
- return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
+ return 1 << (PAGE_SHIFT + mapping_max_folio_order(inode->i_mapping) -
+ inode->i_sb->s_blocksize_bits);
}

/*
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 023e8abdb99a..ebbcdab474d5 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1723,7 +1723,7 @@ static inline int tid_geq(tid_t x, tid_t y)
return (difference >= 0);
}

-extern int jbd2_journal_blocks_per_page(struct inode *inode);
+extern int jbd2_journal_blocks_per_folio(struct inode *inode);
extern size_t journal_tag_bytes(journal_t *journal);

static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
--
2.46.1