[PATCH v4 00/24] ext4: enable block size larger than page size

[PATCH v4 00/24] ext4: enable block size larger than page size

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Changes since v3:
 * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
    (Thank you for your review!)
 * Patch 21: Fix lock imbalance in ext4_change_inode_journal_flag.
    (Suggested by Dan Carpenter)

[v3]: https://lore.kernel.org/r/20251111142634.3301616-1-libaokun@huaweicloud.com

Changes since v2:
 * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
    (Thank you for your review!)
 * Patch 21: Before switching the inode journalling mode, drop all
    page cache of that inode and invoke filemap_write_and_wait()
    unconditionally. (Suggested by Jan Kara)
 * Patch 22: Extend fs-verity to support large folios in addition to
    large block size. (Suggested by Jan Kara)
 * Patch 24: Add a blocksize_gt_pagesize sysfs interface to help users
    (e.g., mke2fs) determine whether the current kernel supports bs > ps.
    In addition, remove the experimental tag. (Suggested by Theodore Ts'o)

[v2]: https://lore.kernel.org/r/20251107144249.435029-1-libaokun@huaweicloud.com

Changes since v1:
 * Collect RVB from Jan Kara and Zhang Yi. (Thanks for your review!)
 * Patch 4: Just use blocksize in the rounding.(Suggested by Jan Kara)
 * Patch 7: use kvmalloc() instead of allocating contiguous physical
    pages.(Suggested by Jan Kara)
 * Patch 12: Fix some typos.(Suggested by Jan Kara)
 * Use clearer naming: EXT4_LBLK_TO_PG() and EXT4_PG_TO_LBLK().
    (Suggested by Jan Kara)
 * Patch 21: removed. After rebasing on Ted’s latest dev branch, this
    patch is no longer needed.
 * Patch 22-23: removed. The issue was resolved by removing the WARN_ON
    in the MM code, so we now rely on patch [1].(Suggested by Matthew)
 * Add new Patch 21 to support data=journal under LBS. (Suggested by
    Jan Kara)
 * Add new Patch 22 to support fs verity under LBS.
 * New Patch 23: add the s_max_folio_order field instead of introducing
    the EXT4_MF_LARGE_FOLIO flag.
 * New Patch 24: rebase adaptation.

[v1]: https://lore.kernel.org/r/20251025032221.2905818-1-libaokun@huaweicloud.com

======

This series enables block size > page size (Large Block Size) in EXT4.

Since large folios are already supported for regular files, the required
changes are not substantial, but they are scattered across the code.
The changes primarily focus on cleaning up potential division-by-zero
errors, resolving negative left/right shifts, and correctly handling
mutually exclusive mount options.

One somewhat troublesome issue is that allocating page units greater than
order-1 with __GFP_NOFAIL in __alloc_pages_slowpath() can trigger an
unexpected WARN_ON. With LBS support, EXT4 and jbd2 may use __GFP_NOFAIL
to allocate large folios when reading metadata. The issue was resolved by
removing the WARN_ON in the MM code, so we now rely on patch [1].

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ee040cbd6e48

Patch series based on Ted’s latest dev branch.

`kvm-xfstests -c ext4/all -g auto` has been executed with no new failures.
`kvm-xfstests -c ext4/32k -g auto` has been executed with no new failures.
`kvm-xfstests -c ext4/64k -g auto` has been executed with no new failures,
but allocation failures for large folios may trigger warn_alloc() warnings,
tests with 32k or smaller block sizes have not exhibited any page allocation
failures.

Here are some performance test data for your reference:

Testing EXT4 filesystems with different block sizes, measuring
single-threaded dd bandwidth for BIO/DIO with varying bs values.

Before(PAGE_SIZE=4096):

      BIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
--------------|----------|----------|----------|----------|------------
 4k           | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
 8k (bigalloc)| 1.4 GB/s | 2.0 GB/s | 2.6 GB/s | 3.1 GB/s | 3.4 GB/s
 16k(bigalloc)| 1.5 GB/s | 2.0 GB/s | 2.6 GB/s | 3.2 GB/s | 3.6 GB/s
 32k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.7 GB/s | 3.3 GB/s | 3.7 GB/s
 64k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
              
      DIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
--------------|----------|----------|----------|----------|------------
 4k           | 194 MB/s | 366 MB/s | 626 MB/s | 1.0 GB/s | 1.4 GB/s
 8k (bigalloc)| 188 MB/s | 359 MB/s | 612 MB/s | 996 MB/s | 1.4 GB/s
 16k(bigalloc)| 208 MB/s | 378 MB/s | 642 MB/s | 1.0 GB/s | 1.4 GB/s
 32k(bigalloc)| 184 MB/s | 368 MB/s | 637 MB/s | 995 MB/s | 1.4 GB/s
 64k(bigalloc)| 208 MB/s | 389 MB/s | 634 MB/s | 1.0 GB/s | 1.4 GB/s

Patched(PAGE_SIZE=4096):

   BIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
---------|----------|----------|----------|----------|------------
 4k      | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
 8k (LBS)| 1.7 GB/s | 2.3 GB/s | 3.2 GB/s | 4.2 GB/s | 4.7 GB/s
 16k(LBS)| 2.0 GB/s | 2.7 GB/s | 3.6 GB/s | 4.7 GB/s | 5.4 GB/s
 32k(LBS)| 2.2 GB/s | 3.1 GB/s | 3.9 GB/s | 4.9 GB/s | 5.7 GB/s
 64k(LBS)| 2.4 GB/s | 3.3 GB/s | 4.2 GB/s | 5.1 GB/s | 6.0 GB/s

   DIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
---------|----------|----------|----------|----------|------------
 4k      | 204 MB/s | 355 MB/s | 627 MB/s | 1.0 GB/s | 1.4 GB/s
 8k (LBS)| 210 MB/s | 356 MB/s | 602 MB/s | 997 MB/s | 1.4 GB/s
 16k(LBS)| 191 MB/s | 361 MB/s | 589 MB/s | 981 MB/s | 1.4 GB/s
 32k(LBS)| 181 MB/s | 330 MB/s | 581 MB/s | 951 MB/s | 1.3 GB/s
 64k(LBS)| 148 MB/s | 272 MB/s | 499 MB/s | 840 MB/s | 1.3 GB/s


The results show:

 * The code changes have almost no impact on the original 4k write
   performance of ext4.
 * Compared with bigalloc, LBS improves BIO write performance by about 50%
   on average.
 * Compared with bigalloc, LBS shows degradation in DIO write performance,
   which increases as the filesystem block size grows and the test bs
   decreases, with a maximum degradation of about 30%.

The DIO regression is primarily due to the increased time spent in
crc32c_arch() within ext4_block_bitmap_csum_set() during block allocation,
as the block size grows larger. This indicates that larger filesystem block
sizes are not always better; please choose an appropriate block size based
on your I/O workload characteristics.

We are also planning further optimizations for block allocation under LBS
in the future.

Comments and questions are, as always, welcome.

Thanks,
Baokun


Baokun Li (21):
  ext4: remove page offset calculation in ext4_block_truncate_page()
  ext4: remove PAGE_SIZE checks for rec_len conversion
  ext4: make ext4_punch_hole() support large block size
  ext4: enable DIOREAD_NOLOCK by default for BS > PS as well
  ext4: introduce s_min_folio_order for future BS > PS support
  ext4: support large block size in ext4_calculate_overhead()
  ext4: support large block size in ext4_readdir()
  ext4: add EXT4_LBLK_TO_B macro for logical block to bytes conversion
  ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page
    conversion
  ext4: support large block size in ext4_mb_load_buddy_gfp()
  ext4: support large block size in ext4_mb_get_buddy_page_lock()
  ext4: support large block size in ext4_mb_init_cache()
  ext4: prepare buddy cache inode for BS > PS with large folios
  ext4: support large block size in ext4_mpage_readpages()
  ext4: support large block size in ext4_block_write_begin()
  ext4: support large block size in mpage_map_and_submit_buffers()
  ext4: support large block size in mpage_prepare_extent_to_map()
  ext4: make data=journal support large block size
  ext4: support verifying data from large folios with fs-verity
  ext4: add checks for large folio incompatibilities when BS > PS
  ext4: enable block size larger than page size

Zhihao Cheng (3):
  ext4: remove page offset calculation in ext4_block_zero_page_range()
  ext4: rename 'page' references to 'folio' in multi-block allocator
  ext4: support large block size in __ext4_block_zero_page_range()

 fs/ext4/dir.c       |   8 +--
 fs/ext4/ext4.h      |  26 ++++-----
 fs/ext4/ext4_jbd2.c |   3 +-
 fs/ext4/extents.c   |   2 +-
 fs/ext4/inode.c     | 112 +++++++++++++++---------------------
 fs/ext4/mballoc.c   | 137 +++++++++++++++++++++++---------------------
 fs/ext4/namei.c     |   8 +--
 fs/ext4/readpage.c  |   7 +--
 fs/ext4/super.c     |  61 ++++++++++++++++----
 fs/ext4/sysfs.c     |   6 ++
 fs/ext4/verity.c    |   2 +-
 11 files changed, 197 insertions(+), 175 deletions(-)

-- 
2.46.1

[PATCH v4 01/24] ext4: remove page offset calculation in ext4_block_zero_page_range()

[libaokun]

From: Zhihao Cheng <chengzhihao1@huawei.com>

For bs <= ps scenarios, calculating the offset within the block is
sufficient. For bs > ps, an initial page offset calculation can lead to
incorrect behavior. Thus this redundant calculation has been removed.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 32d9f0b36c33..dd8726a9046b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4165,9 +4165,8 @@ static int ext4_block_zero_page_range(handle_t *handle,
 		struct address_space *mapping, loff_t from, loff_t length)
 {
 	struct inode *inode = mapping->host;
-	unsigned offset = from & (PAGE_SIZE-1);
 	unsigned blocksize = inode->i_sb->s_blocksize;
-	unsigned max = blocksize - (offset & (blocksize - 1));
+	unsigned int max = blocksize - (from & (blocksize - 1));
 
 	/*
 	 * correct length if it does not fall between
-- 
2.46.1

[PATCH v4 02/24] ext4: remove page offset calculation in ext4_block_truncate_page()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

For bs <= ps scenarios, calculating the offset within the block is
sufficient. For bs > ps, an initial page offset calculation can lead to
incorrect behavior. Thus this redundant calculation has been removed.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index dd8726a9046b..c956aff677ac 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4191,7 +4191,6 @@ static int ext4_block_zero_page_range(handle_t *handle,
 static int ext4_block_truncate_page(handle_t *handle,
 		struct address_space *mapping, loff_t from)
 {
-	unsigned offset = from & (PAGE_SIZE-1);
 	unsigned length;
 	unsigned blocksize;
 	struct inode *inode = mapping->host;
@@ -4200,8 +4199,8 @@ static int ext4_block_truncate_page(handle_t *handle,
 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
 		return 0;
 
-	blocksize = inode->i_sb->s_blocksize;
-	length = blocksize - (offset & (blocksize - 1));
+	blocksize = i_blocksize(inode);
+	length = blocksize - (from & (blocksize - 1));
 
 	return ext4_block_zero_page_range(handle, mapping, from, length);
 }
-- 
2.46.1

[PATCH v4 03/24] ext4: remove PAGE_SIZE checks for rec_len conversion

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Previously, ext4_rec_len_(to|from)_disk only performed complex rec_len
conversions when PAGE_SIZE >= 65536 to reduce complexity.

However, we are soon to support file system block sizes greater than
page size, which makes these conditional checks unnecessary. Thus, these
checks are now removed.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ext4.h | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9f127aedbaee..3d18e6bf43cf 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2475,28 +2475,19 @@ static inline unsigned int ext4_dir_rec_len(__u8 name_len,
 	return (rec_len & ~EXT4_DIR_ROUND);
 }
 
-/*
- * If we ever get support for fs block sizes > page_size, we'll need
- * to remove the #if statements in the next two functions...
- */
 static inline unsigned int
 ext4_rec_len_from_disk(__le16 dlen, unsigned blocksize)
 {
 	unsigned len = le16_to_cpu(dlen);
 
-#if (PAGE_SIZE >= 65536)
 	if (len == EXT4_MAX_REC_LEN || len == 0)
 		return blocksize;
 	return (len & 65532) | ((len & 3) << 16);
-#else
-	return len;
-#endif
 }
 
 static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize)
 {
 	BUG_ON((len > blocksize) || (blocksize > (1 << 18)) || (len & 3));
-#if (PAGE_SIZE >= 65536)
 	if (len < 65536)
 		return cpu_to_le16(len);
 	if (len == blocksize) {
@@ -2506,9 +2497,6 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize)
 			return cpu_to_le16(0);
 	}
 	return cpu_to_le16((len & 65532) | ((len >> 16) & 3));
-#else
-	return cpu_to_le16(len);
-#endif
 }
 
 /*
-- 
2.46.1

[PATCH v4 04/24] ext4: make ext4_punch_hole() support large block size

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

When preparing for bs > ps support, clean up unnecessary PAGE_SIZE
references in ext4_punch_hole().

Previously, when a hole extended beyond i_size, we aligned the hole end
upwards to PAGE_SIZE to handle partial folio invalidation. Now that
truncate_inode_pages_range() already handles partial folio invalidation
correctly, this alignment is no longer required.

However, to save pointless tail block zeroing, we still keep rounding up
to the block size here.

In addition, as Honza pointed out, when the hole end equals i_size, it
should also be rounded up to the block size. This patch fixes that as well.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c956aff677ac..d11df0f4c546 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4406,10 +4406,10 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 
 	/*
 	 * If the hole extends beyond i_size, set the hole to end after
-	 * the page that contains i_size.
+	 * the block that contains i_size to save pointless tail block zeroing.
 	 */
-	if (end > inode->i_size)
-		end = round_up(inode->i_size, PAGE_SIZE);
+	if (end >= inode->i_size)
+		end = round_up(inode->i_size, sb->s_blocksize);
 	if (end > max_end)
 		end = max_end;
 	length = end - offset;
-- 
2.46.1

[PATCH v4 05/24] ext4: enable DIOREAD_NOLOCK by default for BS > PS as well

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

The dioread_nolock related processes already support large folio, so
dioread_nolock is enabled by default regardless of whether the blocksize
is less than, equal to, or greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/super.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 707f890d674e..f39679892e71 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4392,8 +4392,7 @@ static void ext4_set_def_opts(struct super_block *sb,
 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
 		set_opt(sb, DELALLOC);
 
-	if (sb->s_blocksize <= PAGE_SIZE)
-		set_opt(sb, DIOREAD_NOLOCK);
+	set_opt(sb, DIOREAD_NOLOCK);
 }
 
 static int ext4_handle_clustersize(struct super_block *sb)
-- 
2.46.1

[PATCH v4 06/24] ext4: introduce s_min_folio_order for future BS > PS support

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

This commit introduces the s_min_folio_order field to the ext4_sb_info
structure. This field will store the minimum folio order required by the
current filesystem, laying groundwork for future support of block sizes
greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/ext4/ext4.h  |  3 +++
 fs/ext4/inode.c |  3 ++-
 fs/ext4/super.c | 10 +++++-----
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3d18e6bf43cf..6fe8cc3bf9a5 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1688,6 +1688,9 @@ struct ext4_sb_info {
 	/* record the last minlen when FITRIM is called. */
 	unsigned long s_last_trim_minblks;
 
+	/* minimum folio order of a page cache allocation */
+	unsigned int s_min_folio_order;
+
 	/* Precomputed FS UUID checksum for seeding other checksums */
 	__u32 s_csum_seed;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d11df0f4c546..e8da685ede49 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5181,7 +5181,8 @@ void ext4_set_inode_mapping_order(struct inode *inode)
 	if (!ext4_should_enable_large_folio(inode))
 		return;
 
-	mapping_set_folio_order_range(inode->i_mapping, 0,
+	mapping_set_folio_order_range(inode->i_mapping,
+				      EXT4_SB(inode->i_sb)->s_min_folio_order,
 				      EXT4_MAX_PAGECACHE_ORDER(inode));
 }
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f39679892e71..2286cd1e3cb8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5109,11 +5109,8 @@ static int ext4_load_super(struct super_block *sb, ext4_fsblk_t *lsb,
 	 * If the default block size is not the same as the real block size,
 	 * we need to reload it.
 	 */
-	if (sb->s_blocksize == blocksize) {
-		*lsb = logical_sb_block;
-		sbi->s_sbh = bh;
-		return 0;
-	}
+	if (sb->s_blocksize == blocksize)
+		goto success;
 
 	/*
 	 * bh must be released before kill_bdev(), otherwise
@@ -5144,6 +5141,9 @@ static int ext4_load_super(struct super_block *sb, ext4_fsblk_t *lsb,
 		ext4_msg(sb, KERN_ERR, "Magic mismatch, very weird!");
 		goto out;
 	}
+
+success:
+	sbi->s_min_folio_order = get_order(blocksize);
 	*lsb = logical_sb_block;
 	sbi->s_sbh = bh;
 	return 0;
-- 
2.46.1

[PATCH v4 07/24] ext4: support large block size in ext4_calculate_overhead()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

ext4_calculate_overhead() used a single page for its bitmap buffer, which
worked fine when PAGE_SIZE >= block size. However, with block size greater
than page size (BS > PS) support, the bitmap can exceed a single page.

To address this, we now use kvmalloc() to allocate memory of the filesystem
block size, to properly support BS > PS.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/super.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2286cd1e3cb8..998ddce49093 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4191,7 +4191,7 @@ int ext4_calculate_overhead(struct super_block *sb)
 	unsigned int j_blocks, j_inum = le32_to_cpu(es->s_journal_inum);
 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
 	ext4_fsblk_t overhead = 0;
-	char *buf = (char *) get_zeroed_page(GFP_NOFS);
+	char *buf = kvmalloc(sb->s_blocksize, GFP_NOFS | __GFP_ZERO);
 
 	if (!buf)
 		return -ENOMEM;
@@ -4216,7 +4216,7 @@ int ext4_calculate_overhead(struct super_block *sb)
 		blks = count_overhead(sb, i, buf);
 		overhead += blks;
 		if (blks)
-			memset(buf, 0, PAGE_SIZE);
+			memset(buf, 0, sb->s_blocksize);
 		cond_resched();
 	}
 
@@ -4239,7 +4239,7 @@ int ext4_calculate_overhead(struct super_block *sb)
 	}
 	sbi->s_overhead = overhead;
 	smp_wmb();
-	free_page((unsigned long) buf);
+	kvfree(buf);
 	return 0;
 }
 
-- 
2.46.1

[PATCH v4 08/24] ext4: support large block size in ext4_readdir()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

In ext4_readdir(), page_cache_sync_readahead() is used to readahead mapped
physical blocks. With LBS support, this can lead to a negative right shift.

To fix this, the page index is now calculated by first converting the
physical block number (pblk) to a file position (pos) before converting
it to a page index. Also, the correct number of pages to readahead is now
passed.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/ext4/dir.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index d4164c507a90..256fe2c1d4c1 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -192,13 +192,13 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 			continue;
 		}
 		if (err > 0) {
-			pgoff_t index = map.m_pblk >>
-					(PAGE_SHIFT - inode->i_blkbits);
+			pgoff_t index = map.m_pblk << inode->i_blkbits >>
+					PAGE_SHIFT;
 			if (!ra_has_index(&file->f_ra, index))
 				page_cache_sync_readahead(
 					sb->s_bdev->bd_mapping,
-					&file->f_ra, file,
-					index, 1);
+					&file->f_ra, file, index,
+					1 << EXT4_SB(sb)->s_min_folio_order);
 			file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
 			bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 			if (IS_ERR(bh)) {
-- 
2.46.1

[PATCH v4 09/24] ext4: add EXT4_LBLK_TO_B macro for logical block to bytes conversion

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

No functional changes.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ext4.h    |  1 +
 fs/ext4/extents.c |  2 +-
 fs/ext4/inode.c   | 20 +++++++++-----------
 fs/ext4/namei.c   |  8 +++-----
 fs/ext4/verity.c  |  2 +-
 5 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6fe8cc3bf9a5..c00ce6db69f0 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -368,6 +368,7 @@ struct ext4_io_submit {
 								  blkbits))
 #define EXT4_B_TO_LBLK(inode, offset) \
 	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
+#define EXT4_LBLK_TO_B(inode, lblk) ((loff_t)(lblk) << (inode)->i_blkbits)
 
 /* Translate a block number to a cluster number */
 #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c7d219e6c6d8..13c3cfeb13bc 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4562,7 +4562,7 @@ static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
 		 * allow a full retry cycle for any remaining allocations
 		 */
 		retries = 0;
-		epos = (loff_t)(map.m_lblk + ret) << blkbits;
+		epos = EXT4_LBLK_TO_B(inode, map.m_lblk + ret);
 		inode_set_ctime_current(inode);
 		if (new_size) {
 			if (epos > new_size)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e8da685ede49..65a9c04bc691 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -831,9 +831,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
 		    !ext4_is_quota_file(inode) &&
 		    ext4_should_order_data(inode)) {
-			loff_t start_byte =
-				(loff_t)map->m_lblk << inode->i_blkbits;
-			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
+			loff_t start_byte = EXT4_LBLK_TO_B(inode, map->m_lblk);
+			loff_t length = EXT4_LBLK_TO_B(inode, map->m_len);
 
 			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
 				ret = ext4_jbd2_inode_add_wait(handle, inode,
@@ -2233,7 +2232,6 @@ static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
 	ext4_lblk_t lblk = *m_lblk;
 	ext4_fsblk_t pblock = *m_pblk;
 	int err = 0;
-	int blkbits = mpd->inode->i_blkbits;
 	ssize_t io_end_size = 0;
 	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
 
@@ -2259,7 +2257,8 @@ static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
 					err = PTR_ERR(io_end_vec);
 					goto out;
 				}
-				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
+				io_end_vec->offset = EXT4_LBLK_TO_B(mpd->inode,
+								mpd->map.m_lblk);
 			}
 			*map_bh = true;
 			goto out;
@@ -2269,7 +2268,7 @@ static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
 			bh->b_blocknr = pblock++;
 		}
 		clear_buffer_unwritten(bh);
-		io_end_size += (1 << blkbits);
+		io_end_size += i_blocksize(mpd->inode);
 	} while (lblk++, (bh = bh->b_this_page) != head);
 
 	io_end_vec->size += io_end_size;
@@ -2471,7 +2470,7 @@ static int mpage_map_and_submit_extent(handle_t *handle,
 	io_end_vec = ext4_alloc_io_end_vec(io_end);
 	if (IS_ERR(io_end_vec))
 		return PTR_ERR(io_end_vec);
-	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
+	io_end_vec->offset = EXT4_LBLK_TO_B(inode, map->m_lblk);
 	do {
 		err = mpage_map_one_extent(handle, mpd);
 		if (err < 0) {
@@ -3511,8 +3510,8 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
 		iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
 	else
 		iomap->bdev = inode->i_sb->s_bdev;
-	iomap->offset = (u64) map->m_lblk << blkbits;
-	iomap->length = (u64) map->m_len << blkbits;
+	iomap->offset = EXT4_LBLK_TO_B(inode, map->m_lblk);
+	iomap->length = EXT4_LBLK_TO_B(inode, map->m_len);
 
 	if ((map->m_flags & EXT4_MAP_MAPPED) &&
 	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
@@ -3686,7 +3685,6 @@ static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
 			    unsigned int flags)
 {
 	handle_t *handle;
-	u8 blkbits = inode->i_blkbits;
 	int ret, dio_credits, m_flags = 0, retries = 0;
 	bool force_commit = false;
 
@@ -3745,7 +3743,7 @@ static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
 	 * i_disksize out to i_size. This could be beyond where direct I/O is
 	 * happening and thus expose allocated blocks to direct I/O reads.
 	 */
-	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
+	else if (EXT4_LBLK_TO_B(inode, map->m_lblk) >= i_size_read(inode))
 		m_flags = EXT4_GET_BLOCKS_CREATE;
 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 045616033515..c4b5e252af0e 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1076,7 +1076,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 	for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
 		if (ext4_check_dir_entry(dir, NULL, de, bh,
 				bh->b_data, bh->b_size,
-				(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
+				EXT4_LBLK_TO_B(dir, block)
 					 + ((char *)de - bh->b_data))) {
 			/* silently ignore the rest of the block */
 			break;
@@ -1630,7 +1630,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir,
 		}
 		set_buffer_verified(bh);
 		i = search_dirblock(bh, dir, fname,
-			    block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
+				    EXT4_LBLK_TO_B(dir, block), res_dir);
 		if (i == 1) {
 			EXT4_I(dir)->i_dir_start_lookup = block;
 			ret = bh;
@@ -1710,7 +1710,6 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 			struct ext4_filename *fname,
 			struct ext4_dir_entry_2 **res_dir)
 {
-	struct super_block * sb = dir->i_sb;
 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
 	struct buffer_head *bh;
 	ext4_lblk_t block;
@@ -1729,8 +1728,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 			goto errout;
 
 		retval = search_dirblock(bh, dir, fname,
-					 block << EXT4_BLOCK_SIZE_BITS(sb),
-					 res_dir);
+					 EXT4_LBLK_TO_B(dir, block), res_dir);
 		if (retval == 1)
 			goto success;
 		brelse(bh);
diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
index b0acb0c50313..415d9c4d8a32 100644
--- a/fs/ext4/verity.c
+++ b/fs/ext4/verity.c
@@ -302,7 +302,7 @@ static int ext4_get_verity_descriptor_location(struct inode *inode,
 
 	end_lblk = le32_to_cpu(last_extent->ee_block) +
 		   ext4_ext_get_actual_len(last_extent);
-	desc_size_pos = (u64)end_lblk << inode->i_blkbits;
+	desc_size_pos = EXT4_LBLK_TO_B(inode, end_lblk);
 	ext4_free_ext_path(path);
 
 	if (desc_size_pos < sizeof(desc_size_disk))
-- 
2.46.1

[PATCH v4 10/24] ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page conversion

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

As BS > PS support is coming, all block number to page index (and
vice-versa) conversions must now go via bytes. Added EXT4_LBLK_TO_PG()
and EXT4_PG_TO_LBLK() macros to simplify these conversions and handle
both BS <= PS and BS > PS scenarios cleanly.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ext4.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c00ce6db69f0..4bc0b2b7288a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -370,6 +370,12 @@ struct ext4_io_submit {
 	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
 #define EXT4_LBLK_TO_B(inode, lblk) ((loff_t)(lblk) << (inode)->i_blkbits)
 
+/* Translate a block number to a page index */
+#define EXT4_LBLK_TO_PG(inode, lblk)	(EXT4_LBLK_TO_B((inode), (lblk)) >> \
+					 PAGE_SHIFT)
+/* Translate a page index to a block number */
+#define EXT4_PG_TO_LBLK(inode, pnum)	(((loff_t)(pnum) << PAGE_SHIFT) >> \
+					 (inode)->i_blkbits)
 /* Translate a block number to a cluster number */
 #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
 /* Translate a cluster number to a block number */
-- 
2.46.1

[PATCH v4 11/24] ext4: support large block size in ext4_mb_load_buddy_gfp()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Currently, ext4_mb_load_buddy_gfp() uses blocks_per_page to calculate the
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.

To support BS > PS, use bytes to compute folio index and offset within
folio to get rid of blocks_per_page.

Also, if buddy and bitmap land in the same folio, we get that folio’s ref
instead of looking it up again before updating the buddy.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9087183602e4..143d6ff1fdef 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1642,17 +1642,15 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 
 /*
  * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
- * block group lock of all groups for this page; do not hold the BG lock when
+ * block group lock of all groups for this folio; do not hold the BG lock when
  * calling this routine!
  */
 static noinline_for_stack int
 ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 		       struct ext4_buddy *e4b, gfp_t gfp)
 {
-	int blocks_per_page;
 	int block;
 	int pnum;
-	int poff;
 	struct folio *folio;
 	int ret;
 	struct ext4_group_info *grp;
@@ -1662,7 +1660,6 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	might_sleep();
 	mb_debug(sb, "load group %u\n", group);
 
-	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
 	grp = ext4_get_group_info(sb, group);
 	if (!grp)
 		return -EFSCORRUPTED;
@@ -1690,8 +1687,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	 * So for each group we need two blocks.
 	 */
 	block = group * 2;
-	pnum = block / blocks_per_page;
-	poff = block % blocks_per_page;
+	pnum = EXT4_LBLK_TO_PG(inode, block);
 
 	/* Avoid locking the folio in the fast path ... */
 	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
@@ -1723,7 +1719,8 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 					goto err;
 				}
 				mb_cmp_bitmaps(e4b, folio_address(folio) +
-					       (poff * sb->s_blocksize));
+					offset_in_folio(folio,
+						EXT4_LBLK_TO_B(inode, block)));
 			}
 			folio_unlock(folio);
 		}
@@ -1739,12 +1736,18 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 
 	/* Folios marked accessed already */
 	e4b->bd_bitmap_folio = folio;
-	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
+	e4b->bd_bitmap = folio_address(folio) +
+			 offset_in_folio(folio, EXT4_LBLK_TO_B(inode, block));
 
 	block++;
-	pnum = block / blocks_per_page;
-	poff = block % blocks_per_page;
+	pnum = EXT4_LBLK_TO_PG(inode, block);
+	/* buddy and bitmap are on the same folio? */
+	if (folio_contains(folio, pnum)) {
+		folio_get(folio);
+		goto update_buddy;
+	}
 
+	/* we need another folio for the buddy */
 	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
 	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
 		if (!IS_ERR(folio))
@@ -1779,9 +1782,11 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 		goto err;
 	}
 
+update_buddy:
 	/* Folios marked accessed already */
 	e4b->bd_buddy_folio = folio;
-	e4b->bd_buddy = folio_address(folio) + (poff * sb->s_blocksize);
+	e4b->bd_buddy = folio_address(folio) +
+			offset_in_folio(folio, EXT4_LBLK_TO_B(inode, block));
 
 	return 0;
 
-- 
2.46.1

[PATCH v4 12/24] ext4: support large block size in ext4_mb_get_buddy_page_lock()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Currently, ext4_mb_get_buddy_page_lock() uses blocks_per_page to calculate
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.

To support BS > PS, use bytes to compute folio index and offset within
folio to get rid of blocks_per_page.

Also, since ext4_mb_get_buddy_page_lock() already fully supports folio,
rename it to ext4_mb_get_buddy_folio_lock().

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 143d6ff1fdef..b454a41dd6c1 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1510,50 +1510,52 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 }
 
 /*
- * Lock the buddy and bitmap pages. This make sure other parallel init_group
- * on the same buddy page doesn't happen whild holding the buddy page lock.
- * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
- * are on the same page e4b->bd_buddy_folio is NULL and return value is 0.
+ * Lock the buddy and bitmap folios. This makes sure other parallel init_group
+ * on the same buddy folio doesn't happen while holding the buddy folio lock.
+ * Return locked buddy and bitmap folios on e4b struct. If buddy and bitmap
+ * are on the same folio e4b->bd_buddy_folio is NULL and return value is 0.
  */
-static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
+static int ext4_mb_get_buddy_folio_lock(struct super_block *sb,
 		ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
 {
 	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
-	int block, pnum, poff;
-	int blocks_per_page;
+	int block, pnum;
 	struct folio *folio;
 
 	e4b->bd_buddy_folio = NULL;
 	e4b->bd_bitmap_folio = NULL;
 
-	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
 	/*
 	 * the buddy cache inode stores the block bitmap
 	 * and buddy information in consecutive blocks.
 	 * So for each group we need two blocks.
 	 */
 	block = group * 2;
-	pnum = block / blocks_per_page;
-	poff = block % blocks_per_page;
+	pnum = EXT4_LBLK_TO_PG(inode, block);
 	folio = __filemap_get_folio(inode->i_mapping, pnum,
 			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
 	BUG_ON(folio->mapping != inode->i_mapping);
+	WARN_ON_ONCE(folio_size(folio) < sb->s_blocksize);
 	e4b->bd_bitmap_folio = folio;
-	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
+	e4b->bd_bitmap = folio_address(folio) +
+			 offset_in_folio(folio, EXT4_LBLK_TO_B(inode, block));
 
-	if (blocks_per_page >= 2) {
-		/* buddy and bitmap are on the same page */
+	block++;
+	pnum = EXT4_LBLK_TO_PG(inode, block);
+	if (folio_contains(folio, pnum)) {
+		/* buddy and bitmap are on the same folio */
 		return 0;
 	}
 
-	/* blocks_per_page == 1, hence we need another page for the buddy */
-	folio = __filemap_get_folio(inode->i_mapping, block + 1,
+	/* we need another folio for the buddy */
+	folio = __filemap_get_folio(inode->i_mapping, pnum,
 			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
 	BUG_ON(folio->mapping != inode->i_mapping);
+	WARN_ON_ONCE(folio_size(folio) < sb->s_blocksize);
 	e4b->bd_buddy_folio = folio;
 	return 0;
 }
@@ -1592,14 +1594,14 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 
 	/*
 	 * This ensures that we don't reinit the buddy cache
-	 * page which map to the group from which we are already
+	 * folio which map to the group from which we are already
 	 * allocating. If we are looking at the buddy cache we would
 	 * have taken a reference using ext4_mb_load_buddy and that
-	 * would have pinned buddy page to page cache.
-	 * The call to ext4_mb_get_buddy_page_lock will mark the
-	 * page accessed.
+	 * would have pinned buddy folio to page cache.
+	 * The call to ext4_mb_get_buddy_folio_lock will mark the
+	 * folio accessed.
 	 */
-	ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
+	ret = ext4_mb_get_buddy_folio_lock(sb, group, &e4b, gfp);
 	if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
 		/*
 		 * somebody initialized the group
-- 
2.46.1

[PATCH v4 13/24] ext4: support large block size in ext4_mb_init_cache()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Currently, ext4_mb_init_cache() uses blocks_per_page to calculate the
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.

Since we now have the folio, we know its exact size. This allows us to
convert {blocks, groups}_per_page to {blocks, groups}_per_folio, thus
supporting block sizes greater than page size.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index b454a41dd6c1..3f10c64ab2b1 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1329,26 +1329,25 @@ static void mb_regenerate_buddy(struct ext4_buddy *e4b)
  * block bitmap and buddy information. The information are
  * stored in the inode as
  *
- * {                        page                        }
+ * {                        folio                        }
  * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
  *
  *
  * one block each for bitmap and buddy information.
- * So for each group we take up 2 blocks. A page can
- * contain blocks_per_page (PAGE_SIZE / blocksize)  blocks.
- * So it can have information regarding groups_per_page which
- * is blocks_per_page/2
+ * So for each group we take up 2 blocks. A folio can
+ * contain blocks_per_folio (folio_size / blocksize)  blocks.
+ * So it can have information regarding groups_per_folio which
+ * is blocks_per_folio/2
  *
  * Locking note:  This routine takes the block group lock of all groups
- * for this page; do not hold this lock when calling this routine!
+ * for this folio; do not hold this lock when calling this routine!
  */
-
 static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 {
 	ext4_group_t ngroups;
 	unsigned int blocksize;
-	int blocks_per_page;
-	int groups_per_page;
+	int blocks_per_folio;
+	int groups_per_folio;
 	int err = 0;
 	int i;
 	ext4_group_t first_group, group;
@@ -1365,27 +1364,24 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 	sb = inode->i_sb;
 	ngroups = ext4_get_groups_count(sb);
 	blocksize = i_blocksize(inode);
-	blocks_per_page = PAGE_SIZE / blocksize;
+	blocks_per_folio = folio_size(folio) / blocksize;
+	WARN_ON_ONCE(!blocks_per_folio);
+	groups_per_folio = DIV_ROUND_UP(blocks_per_folio, 2);
 
 	mb_debug(sb, "init folio %lu\n", folio->index);
 
-	groups_per_page = blocks_per_page >> 1;
-	if (groups_per_page == 0)
-		groups_per_page = 1;
-
 	/* allocate buffer_heads to read bitmaps */
-	if (groups_per_page > 1) {
-		i = sizeof(struct buffer_head *) * groups_per_page;
+	if (groups_per_folio > 1) {
+		i = sizeof(struct buffer_head *) * groups_per_folio;
 		bh = kzalloc(i, gfp);
 		if (bh == NULL)
 			return -ENOMEM;
 	} else
 		bh = &bhs;
 
-	first_group = folio->index * blocks_per_page / 2;
-
 	/* read all groups the folio covers into the cache */
-	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+	first_group = EXT4_PG_TO_LBLK(inode, folio->index) / 2;
+	for (i = 0, group = first_group; i < groups_per_folio; i++, group++) {
 		if (group >= ngroups)
 			break;
 
@@ -1393,7 +1389,7 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 		if (!grinfo)
 			continue;
 		/*
-		 * If page is uptodate then we came here after online resize
+		 * If folio is uptodate then we came here after online resize
 		 * which added some new uninitialized group info structs, so
 		 * we must skip all initialized uptodate buddies on the folio,
 		 * which may be currently in use by an allocating task.
@@ -1413,7 +1409,7 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 	}
 
 	/* wait for I/O completion */
-	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+	for (i = 0, group = first_group; i < groups_per_folio; i++, group++) {
 		int err2;
 
 		if (!bh[i])
@@ -1423,8 +1419,8 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 			err = err2;
 	}
 
-	first_block = folio->index * blocks_per_page;
-	for (i = 0; i < blocks_per_page; i++) {
+	first_block = EXT4_PG_TO_LBLK(inode, folio->index);
+	for (i = 0; i < blocks_per_folio; i++) {
 		group = (first_block + i) >> 1;
 		if (group >= ngroups)
 			break;
@@ -1501,7 +1497,7 @@ static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 
 out:
 	if (bh) {
-		for (i = 0; i < groups_per_page; i++)
+		for (i = 0; i < groups_per_folio; i++)
 			brelse(bh[i]);
 		if (bh != &bhs)
 			kfree(bh);
-- 
2.46.1

[PATCH v4 14/24] ext4: prepare buddy cache inode for BS > PS with large folios

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

We use EXT4_BAD_INO for the buddy cache inode number. This inode is not
accessed via __ext4_new_inode() or __ext4_iget(), meaning
ext4_set_inode_mapping_order() is not called to set its folio order range.

However, future block size greater than page size support requires this
inode to support large folios, and the buddy cache code already handles
BS > PS. Therefore, ext4_set_inode_mapping_order() is now explicitly
called for this specific inode to set its folio order range.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 3f10c64ab2b1..102c6439eb11 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3493,6 +3493,8 @@ static int ext4_mb_init_backend(struct super_block *sb)
 	 * this will avoid confusion if it ever shows up during debugging. */
 	sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
 	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
+	ext4_set_inode_mapping_order(sbi->s_buddy_cache);
+
 	for (i = 0; i < ngroups; i++) {
 		cond_resched();
 		desc = ext4_get_group_desc(sb, i, NULL);
-- 
2.46.1

[PATCH v4 15/24] ext4: rename 'page' references to 'folio' in multi-block allocator

[libaokun]

From: Zhihao Cheng <chengzhihao1@huawei.com>

The ext4 multi-block allocator now fully supports folio objects. Update
all variable names, function names, and comments to replace legacy 'page'
terminology with 'folio', improving clarity and consistency.

No functional changes.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 102c6439eb11..0fbd4c5fffc0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -98,14 +98,14 @@
  * block bitmap and buddy information. The information are stored in the
  * inode as:
  *
- *  {                        page                        }
+ *  {                        folio                        }
  *  [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
  *
  *
  * one block each for bitmap and buddy information.  So for each group we
- * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
- * blocksize) blocks.  So it can have information regarding groups_per_page
- * which is blocks_per_page/2
+ * take up 2 blocks. A folio can contain blocks_per_folio (folio_size /
+ * blocksize) blocks.  So it can have information regarding groups_per_folio
+ * which is blocks_per_folio/2
  *
  * The buddy cache inode is not stored on disk. The inode is thrown
  * away when the filesystem is unmounted.
@@ -1556,7 +1556,7 @@ static int ext4_mb_get_buddy_folio_lock(struct super_block *sb,
 	return 0;
 }
 
-static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
+static void ext4_mb_put_buddy_folio_lock(struct ext4_buddy *e4b)
 {
 	if (e4b->bd_bitmap_folio) {
 		folio_unlock(e4b->bd_bitmap_folio);
@@ -1570,7 +1570,7 @@ static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
 
 /*
  * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
- * block group lock of all groups for this page; do not hold the BG lock when
+ * block group lock of all groups for this folio; do not hold the BG lock when
  * calling this routine!
  */
 static noinline_for_stack
@@ -1618,7 +1618,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 	if (e4b.bd_buddy_folio == NULL) {
 		/*
 		 * If both the bitmap and buddy are in
-		 * the same page we don't need to force
+		 * the same folio we don't need to force
 		 * init the buddy
 		 */
 		ret = 0;
@@ -1634,7 +1634,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
 		goto err;
 	}
 err:
-	ext4_mb_put_buddy_page_lock(&e4b);
+	ext4_mb_put_buddy_folio_lock(&e4b);
 	return ret;
 }
 
@@ -2227,7 +2227,7 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
 	ac->ac_buddy = ret >> 16;
 
 	/*
-	 * take the page reference. We want the page to be pinned
+	 * take the folio reference. We want the folio to be pinned
 	 * so that we don't get a ext4_mb_init_cache_call for this
 	 * group until we update the bitmap. That would mean we
 	 * double allocate blocks. The reference is dropped
@@ -2933,7 +2933,7 @@ static int ext4_mb_scan_group(struct ext4_allocation_context *ac,
 	if (cr < CR_ANY_FREE && spin_is_locked(ext4_group_lock_ptr(sb, group)))
 		return 0;
 
-	/* This now checks without needing the buddy page */
+	/* This now checks without needing the buddy folio */
 	ret = ext4_mb_good_group_nolock(ac, group, cr);
 	if (ret <= 0) {
 		if (!ac->ac_first_err)
@@ -4725,7 +4725,7 @@ static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
 				   "ext4: mb_load_buddy failed (%d)", err))
 			/*
 			 * This should never happen since we pin the
-			 * pages in the ext4_allocation_context so
+			 * folios in the ext4_allocation_context so
 			 * ext4_mb_load_buddy() should never fail.
 			 */
 			return;
-- 
2.46.1

[PATCH v4 16/24] ext4: support large block size in ext4_mpage_readpages()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Use the EXT4_PG_TO_LBLK() macro to convert folio indexes to blocks to avoid
negative left shifts after supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/readpage.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index f329daf6e5c7..e7f2350c725b 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -213,9 +213,7 @@ int ext4_mpage_readpages(struct inode *inode,
 {
 	struct bio *bio = NULL;
 	sector_t last_block_in_bio = 0;
-
 	const unsigned blkbits = inode->i_blkbits;
-	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
 	const unsigned blocksize = 1 << blkbits;
 	sector_t next_block;
 	sector_t block_in_file;
@@ -251,9 +249,8 @@ int ext4_mpage_readpages(struct inode *inode,
 
 		blocks_per_folio = folio_size(folio) >> blkbits;
 		first_hole = blocks_per_folio;
-		block_in_file = next_block =
-			(sector_t)folio->index << (PAGE_SHIFT - blkbits);
-		last_block = block_in_file + nr_pages * blocks_per_page;
+		block_in_file = next_block = EXT4_PG_TO_LBLK(inode, folio->index);
+		last_block = EXT4_PG_TO_LBLK(inode, folio->index + nr_pages);
 		last_block_in_file = (ext4_readpage_limit(inode) +
 				      blocksize - 1) >> blkbits;
 		if (last_block > last_block_in_file)
-- 
2.46.1

[PATCH v4 17/24] ext4: support large block size in ext4_block_write_begin()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Use the EXT4_PG_TO_LBLK() macro to convert folio indexes to blocks to avoid
negative left shifts after supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 65a9c04bc691..9259d08d4a59 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1168,8 +1168,7 @@ int ext4_block_write_begin(handle_t *handle, struct folio *folio,
 	unsigned block_start, block_end;
 	sector_t block;
 	int err = 0;
-	unsigned blocksize = inode->i_sb->s_blocksize;
-	unsigned bbits;
+	unsigned int blocksize = i_blocksize(inode);
 	struct buffer_head *bh, *head, *wait[2];
 	int nr_wait = 0;
 	int i;
@@ -1178,12 +1177,12 @@ int ext4_block_write_begin(handle_t *handle, struct folio *folio,
 	BUG_ON(!folio_test_locked(folio));
 	BUG_ON(to > folio_size(folio));
 	BUG_ON(from > to);
+	WARN_ON_ONCE(blocksize > folio_size(folio));
 
 	head = folio_buffers(folio);
 	if (!head)
 		head = create_empty_buffers(folio, blocksize, 0);
-	bbits = ilog2(blocksize);
-	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
+	block = EXT4_PG_TO_LBLK(inode, folio->index);
 
 	for (bh = head, block_start = 0; bh != head || !block_start;
 	    block++, block_start = block_end, bh = bh->b_this_page) {
-- 
2.46.1

[PATCH v4 18/24] ext4: support large block size in mpage_map_and_submit_buffers()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Use the EXT4_PG_TO_LBLK/EXT4_LBLK_TO_PG macros to complete the conversion
between folio indexes and blocks to avoid negative left/right shifts after
supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9259d08d4a59..f076477e2cf8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2297,15 +2297,14 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 	struct folio_batch fbatch;
 	unsigned nr, i;
 	struct inode *inode = mpd->inode;
-	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
 	pgoff_t start, end;
 	ext4_lblk_t lblk;
 	ext4_fsblk_t pblock;
 	int err;
 	bool map_bh = false;
 
-	start = mpd->map.m_lblk >> bpp_bits;
-	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
+	start = EXT4_LBLK_TO_PG(inode, mpd->map.m_lblk);
+	end = EXT4_LBLK_TO_PG(inode, mpd->map.m_lblk + mpd->map.m_len - 1);
 	pblock = mpd->map.m_pblk;
 
 	folio_batch_init(&fbatch);
@@ -2316,7 +2315,7 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 		for (i = 0; i < nr; i++) {
 			struct folio *folio = fbatch.folios[i];
 
-			lblk = folio->index << bpp_bits;
+			lblk = EXT4_PG_TO_LBLK(inode, folio->index);
 			err = mpage_process_folio(mpd, folio, &lblk, &pblock,
 						 &map_bh);
 			/*
-- 
2.46.1

[PATCH v4 19/24] ext4: support large block size in mpage_prepare_extent_to_map()

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Use the EXT4_PG_TO_LBLK/EXT4_LBLK_TO_PG macros to complete the conversion
between folio indexes and blocks to avoid negative left/right shifts after
supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f076477e2cf8..2a8a31a2b29e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2618,7 +2618,6 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 	pgoff_t end = mpd->end_pos >> PAGE_SHIFT;
 	xa_mark_t tag;
 	int i, err = 0;
-	int blkbits = mpd->inode->i_blkbits;
 	ext4_lblk_t lblk;
 	struct buffer_head *head;
 	handle_t *handle = NULL;
@@ -2657,7 +2656,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 			 */
 			if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
 			    mpd->wbc->nr_to_write <=
-			    mpd->map.m_len >> (PAGE_SHIFT - blkbits))
+			    EXT4_LBLK_TO_PG(mpd->inode, mpd->map.m_len))
 				goto out;
 
 			/* If we can't merge this page, we are done. */
@@ -2735,8 +2734,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 				mpage_folio_done(mpd, folio);
 			} else {
 				/* Add all dirty buffers to mpd */
-				lblk = ((ext4_lblk_t)folio->index) <<
-					(PAGE_SHIFT - blkbits);
+				lblk = EXT4_PG_TO_LBLK(mpd->inode, folio->index);
 				head = folio_buffers(folio);
 				err = mpage_process_page_bufs(mpd, head, head,
 						lblk);
-- 
2.46.1

[PATCH v4 20/24] ext4: support large block size in __ext4_block_zero_page_range()

[libaokun]

From: Zhihao Cheng <chengzhihao1@huawei.com>

Use the EXT4_PG_TO_LBLK() macro to convert folio indexes to blocks to avoid
negative left shifts after supporting blocksize greater than PAGE_SIZE.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2a8a31a2b29e..5499b2856f9e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4074,7 +4074,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 
 	blocksize = inode->i_sb->s_blocksize;
 
-	iblock = folio->index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
+	iblock = EXT4_PG_TO_LBLK(inode, folio->index);
 
 	bh = folio_buffers(folio);
 	if (!bh)
-- 
2.46.1

[PATCH v4 21/24] ext4: make data=journal support large block size

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Currently, ext4_set_inode_mapping_order() does not set max folio order
for files with the data journalling flag. For files that already have
large folios enabled, ext4_inode_journal_mode() ignores the data
journalling flag once max folio order is set.

This is not because data journalling cannot work with large folios, but
because credit estimates will go through the roof if there are too many
blocks per folio.

Since the real constraint is blocks-per-folio, to support data=journal
under LBS, we now set max folio order to be equal to min folio order for
files with the journalling flag. When LBS is disabled, the max folio order
remains unset as before.

Therefore, before ext4_change_inode_journal_flag() switches the journalling
mode, we call truncate_pagecache() to drop all page cache for that inode,
and filemap_write_and_wait() is called unconditionally.

After that, once the journalling mode has been switched, we can safely
reset the inode mapping order, and the mapping_large_folio_support() check
in ext4_inode_journal_mode() can be removed.

Suggested-by: Jan Kara <jack@suse.cz>
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ext4_jbd2.c |  3 +--
 fs/ext4/inode.c     | 33 +++++++++++++++++++--------------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index a0e66bc10093..05e5946ed9b3 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -16,8 +16,7 @@ int ext4_inode_journal_mode(struct inode *inode)
 	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) ||
 	    test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
 	    (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
-	    !test_opt(inode->i_sb, DELALLOC) &&
-	    !mapping_large_folio_support(inode->i_mapping))) {
+	    !test_opt(inode->i_sb, DELALLOC))) {
 		/* We do not support data journalling for encrypted data */
 		if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode))
 			return EXT4_INODE_ORDERED_DATA_MODE;  /* ordered */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5499b2856f9e..fff059bfeb52 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5152,9 +5152,6 @@ static bool ext4_should_enable_large_folio(struct inode *inode)
 
 	if (!S_ISREG(inode->i_mode))
 		return false;
-	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
-	    ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
-		return false;
 	if (ext4_has_feature_verity(sb))
 		return false;
 	if (ext4_has_feature_encrypt(sb))
@@ -5172,12 +5169,20 @@ static bool ext4_should_enable_large_folio(struct inode *inode)
 		umin(MAX_PAGECACHE_ORDER, (11 + (i)->i_blkbits - PAGE_SHIFT))
 void ext4_set_inode_mapping_order(struct inode *inode)
 {
+	u32 max_order;
+
 	if (!ext4_should_enable_large_folio(inode))
 		return;
 
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
+		max_order = EXT4_SB(inode->i_sb)->s_min_folio_order;
+	else
+		max_order = EXT4_MAX_PAGECACHE_ORDER(inode);
+
 	mapping_set_folio_order_range(inode->i_mapping,
 				      EXT4_SB(inode->i_sb)->s_min_folio_order,
-				      EXT4_MAX_PAGECACHE_ORDER(inode));
+				      max_order);
 }
 
 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
@@ -6552,14 +6557,14 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
 	 * dirty data which can be converted only after flushing the dirty
 	 * data (and journalled aops don't know how to handle these cases).
 	 */
-	if (val) {
-		filemap_invalidate_lock(inode->i_mapping);
-		err = filemap_write_and_wait(inode->i_mapping);
-		if (err < 0) {
-			filemap_invalidate_unlock(inode->i_mapping);
-			return err;
-		}
+	filemap_invalidate_lock(inode->i_mapping);
+	err = filemap_write_and_wait(inode->i_mapping);
+	if (err < 0) {
+		filemap_invalidate_unlock(inode->i_mapping);
+		return err;
 	}
+	/* Before switch the inode journalling mode evict all the page cache. */
+	truncate_pagecache(inode, 0);
 
 	alloc_ctx = ext4_writepages_down_write(inode->i_sb);
 	jbd2_journal_lock_updates(journal);
@@ -6579,17 +6584,17 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
 		if (err < 0) {
 			jbd2_journal_unlock_updates(journal);
 			ext4_writepages_up_write(inode->i_sb, alloc_ctx);
+			filemap_invalidate_unlock(inode->i_mapping);
 			return err;
 		}
 		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
 	}
 	ext4_set_aops(inode);
+	ext4_set_inode_mapping_order(inode);
 
 	jbd2_journal_unlock_updates(journal);
 	ext4_writepages_up_write(inode->i_sb, alloc_ctx);
-
-	if (val)
-		filemap_invalidate_unlock(inode->i_mapping);
+	filemap_invalidate_unlock(inode->i_mapping);
 
 	/* Finally we can mark the inode as dirty. */
 
-- 
2.46.1

[PATCH v4 22/24] ext4: support verifying data from large folios with fs-verity

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Eric Biggers already added support for verifying data from large folios
several years ago in commit 5d0f0e57ed90 ("fsverity: support verifying
data from large folios").

With ext4 now supporting large block sizes, the fs-verity tests
`kvm-xfstests -c ext4/64k -g verity -x encrypt` pass without issues.

Therefore, remove the restriction and allow large folios to be enabled
together with fs-verity.

Cc: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fff059bfeb52..d2fa3471f59a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5152,8 +5152,6 @@ static bool ext4_should_enable_large_folio(struct inode *inode)
 
 	if (!S_ISREG(inode->i_mode))
 		return false;
-	if (ext4_has_feature_verity(sb))
-		return false;
 	if (ext4_has_feature_encrypt(sb))
 		return false;
 
-- 
2.46.1

[PATCH v4 23/24] ext4: add checks for large folio incompatibilities when BS > PS

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Supporting a block size greater than the page size (BS > PS) requires
support for large folios. However, several features (e.g., encrypt)
do not yet support large folios.

To prevent conflicts, this patch adds checks at mount time to prohibit
these features from being used when BS > PS. Since these features cannot
be changed on remount, there is no need to check on remount.

This patch adds s_max_folio_order, initialized during mount according to
filesystem features and mount options. If s_max_folio_order is 0, large
folios are disabled.

With this in place, ext4_set_inode_mapping_order() can be simplified by
checking s_max_folio_order, avoiding redundant checks.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/ext4.h  |  4 +++-
 fs/ext4/inode.c | 38 ++++++++++----------------------------
 fs/ext4/super.c | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 29 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4bc0b2b7288a..79dc231d6e22 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1696,7 +1696,9 @@ struct ext4_sb_info {
 	unsigned long s_last_trim_minblks;
 
 	/* minimum folio order of a page cache allocation */
-	unsigned int s_min_folio_order;
+	u16 s_min_folio_order;
+	/* supported maximum folio order, 0 means not supported */
+	u16 s_max_folio_order;
 
 	/* Precomputed FS UUID checksum for seeding other checksums */
 	__u32 s_csum_seed;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d2fa3471f59a..61b803a79756 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5146,41 +5146,23 @@ static int check_igot_inode(struct inode *inode, ext4_iget_flags flags,
 	return -EFSCORRUPTED;
 }
 
-static bool ext4_should_enable_large_folio(struct inode *inode)
+void ext4_set_inode_mapping_order(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
+	u16 min_order, max_order;
 
-	if (!S_ISREG(inode->i_mode))
-		return false;
-	if (ext4_has_feature_encrypt(sb))
-		return false;
-
-	return true;
-}
-
-/*
- * Limit the maximum folio order to 2048 blocks to prevent overestimation
- * of reserve handle credits during the folio writeback in environments
- * where the PAGE_SIZE exceeds 4KB.
- */
-#define EXT4_MAX_PAGECACHE_ORDER(i)		\
-		umin(MAX_PAGECACHE_ORDER, (11 + (i)->i_blkbits - PAGE_SHIFT))
-void ext4_set_inode_mapping_order(struct inode *inode)
-{
-	u32 max_order;
+	max_order = EXT4_SB(sb)->s_max_folio_order;
+	if (!max_order)
+		return;
 
-	if (!ext4_should_enable_large_folio(inode))
+	min_order = EXT4_SB(sb)->s_min_folio_order;
+	if (!min_order && !S_ISREG(inode->i_mode))
 		return;
 
-	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
-	    ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
-		max_order = EXT4_SB(inode->i_sb)->s_min_folio_order;
-	else
-		max_order = EXT4_MAX_PAGECACHE_ORDER(inode);
+	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
+		max_order = min_order;
 
-	mapping_set_folio_order_range(inode->i_mapping,
-				      EXT4_SB(inode->i_sb)->s_min_folio_order,
-				      max_order);
+	mapping_set_folio_order_range(inode->i_mapping, min_order, max_order);
 }
 
 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 998ddce49093..3d03a6eb0ea0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5042,6 +5042,41 @@ static const char *ext4_has_journal_option(struct super_block *sb)
 	return NULL;
 }
 
+/*
+ * Limit the maximum folio order to 2048 blocks to prevent overestimation
+ * of reserve handle credits during the folio writeback in environments
+ * where the PAGE_SIZE exceeds 4KB.
+ */
+#define EXT4_MAX_PAGECACHE_ORDER(sb)		\
+		umin(MAX_PAGECACHE_ORDER, (11 + (sb)->s_blocksize_bits - PAGE_SHIFT))
+static void ext4_set_max_mapping_order(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+		sbi->s_max_folio_order = sbi->s_min_folio_order;
+	else
+		sbi->s_max_folio_order = EXT4_MAX_PAGECACHE_ORDER(sb);
+}
+
+static int ext4_check_large_folio(struct super_block *sb)
+{
+	const char *err_str = NULL;
+
+	if (ext4_has_feature_encrypt(sb))
+		err_str = "encrypt";
+
+	if (!err_str) {
+		ext4_set_max_mapping_order(sb);
+	} else if (sb->s_blocksize > PAGE_SIZE) {
+		ext4_msg(sb, KERN_ERR, "bs(%lu) > ps(%lu) unsupported for %s",
+			 sb->s_blocksize, PAGE_SIZE, err_str);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int ext4_load_super(struct super_block *sb, ext4_fsblk_t *lsb,
 			   int silent)
 {
@@ -5318,6 +5353,10 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 
 	ext4_apply_options(fc, sb);
 
+	err = ext4_check_large_folio(sb);
+	if (err < 0)
+		goto failed_mount;
+
 	err = ext4_encoding_init(sb, es);
 	if (err)
 		goto failed_mount;
-- 
2.46.1

[PATCH v4 24/24] ext4: enable block size larger than page size

[libaokun]

From: Baokun Li <libaokun1@huawei.com>

Since block device (See commit 3c20917120ce ("block/bdev: enable large
folio support for large logical block sizes")) and page cache (See commit
ab95d23bab220ef8 ("filemap: allocate mapping_min_order folios in the page
cache")) has the ability to have a minimum order when allocating folio,
and ext4 has supported large folio in commit 7ac67301e82f ("ext4: enable
large folio for regular file"), now add support for block_size > PAGE_SIZE
in ext4.

set_blocksize() -> bdev_validate_blocksize() already validates the block
size, so ext4_load_super() does not need to perform additional checks.
Here we only need to add the FS_LBS bit to fs_flags.

In addition, block sizes larger than the page size are currently supported
only when CONFIG_TRANSPARENT_HUGEPAGE is enabled. To make this explicit,
a blocksize_gt_pagesize entry has been added under /sys/fs/ext4/feature/,
indicating whether bs > ps is supported. This allows mke2fs to check the
interface and determine whether a warning should be issued when formatting
a filesystem with block size larger than the page size.

Suggested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/ext4/super.c | 3 ++-
 fs/ext4/sysfs.c | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3d03a6eb0ea0..87205660c5d0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -7453,7 +7453,8 @@ static struct file_system_type ext4_fs_type = {
 	.init_fs_context	= ext4_init_fs_context,
 	.parameters		= ext4_param_specs,
 	.kill_sb		= ext4_kill_sb,
-	.fs_flags		= FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME,
+	.fs_flags		= FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME |
+				  FS_LBS,
 };
 MODULE_ALIAS_FS("ext4");
 
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 987bd00f916a..0018e09b867e 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -332,6 +332,9 @@ EXT4_ATTR_FEATURE(fast_commit);
 #if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
 EXT4_ATTR_FEATURE(encrypted_casefold);
 #endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+EXT4_ATTR_FEATURE(blocksize_gt_pagesize);
+#endif
 
 static struct attribute *ext4_feat_attrs[] = {
 	ATTR_LIST(lazy_itable_init),
@@ -351,6 +354,9 @@ static struct attribute *ext4_feat_attrs[] = {
 	ATTR_LIST(fast_commit),
 #if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
 	ATTR_LIST(encrypted_casefold),
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	ATTR_LIST(blocksize_gt_pagesize),
 #endif
 	NULL,
 };
-- 
2.46.1

Re: [PATCH v4 00/24] ext4: enable block size larger than page size

[Ojaswin Mujoo]

On Fri, Nov 21, 2025 at 05:06:30PM +0800, libaokun@huaweicloud.com wrote:
> From: Baokun Li <libaokun1@huawei.com>
> 
> Changes since v3:
>  * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
>     (Thank you for your review!)
>  * Patch 21: Fix lock imbalance in ext4_change_inode_journal_flag.
>     (Suggested by Dan Carpenter)
> 
> [v3]: https://lore.kernel.org/r/20251111142634.3301616-1-libaokun@huaweicloud.com
> 
> Changes since v2:
>  * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
>     (Thank you for your review!)
>  * Patch 21: Before switching the inode journalling mode, drop all
>     page cache of that inode and invoke filemap_write_and_wait()
>     unconditionally. (Suggested by Jan Kara)
>  * Patch 22: Extend fs-verity to support large folios in addition to
>     large block size. (Suggested by Jan Kara)
>  * Patch 24: Add a blocksize_gt_pagesize sysfs interface to help users
>     (e.g., mke2fs) determine whether the current kernel supports bs > ps.
>     In addition, remove the experimental tag. (Suggested by Theodore Ts'o)
> 
> [v2]: https://lore.kernel.org/r/20251107144249.435029-1-libaokun@huaweicloud.com
> 
> Changes since v1:
>  * Collect RVB from Jan Kara and Zhang Yi. (Thanks for your review!)
>  * Patch 4: Just use blocksize in the rounding.(Suggested by Jan Kara)
>  * Patch 7: use kvmalloc() instead of allocating contiguous physical
>     pages.(Suggested by Jan Kara)
>  * Patch 12: Fix some typos.(Suggested by Jan Kara)
>  * Use clearer naming: EXT4_LBLK_TO_PG() and EXT4_PG_TO_LBLK().
>     (Suggested by Jan Kara)
>  * Patch 21: removed. After rebasing on Ted’s latest dev branch, this
>     patch is no longer needed.
>  * Patch 22-23: removed. The issue was resolved by removing the WARN_ON
>     in the MM code, so we now rely on patch [1].(Suggested by Matthew)
>  * Add new Patch 21 to support data=journal under LBS. (Suggested by
>     Jan Kara)
>  * Add new Patch 22 to support fs verity under LBS.
>  * New Patch 23: add the s_max_folio_order field instead of introducing
>     the EXT4_MF_LARGE_FOLIO flag.
>  * New Patch 24: rebase adaptation.
> 
> [v1]: https://lore.kernel.org/r/20251025032221.2905818-1-libaokun@huaweicloud.com
> 
> ======
> 
> This series enables block size > page size (Large Block Size) in EXT4.
> 
> Since large folios are already supported for regular files, the required
> changes are not substantial, but they are scattered across the code.
> The changes primarily focus on cleaning up potential division-by-zero
> errors, resolving negative left/right shifts, and correctly handling
> mutually exclusive mount options.
> 
> One somewhat troublesome issue is that allocating page units greater than
> order-1 with __GFP_NOFAIL in __alloc_pages_slowpath() can trigger an
> unexpected WARN_ON. With LBS support, EXT4 and jbd2 may use __GFP_NOFAIL
> to allocate large folios when reading metadata. The issue was resolved by
> removing the WARN_ON in the MM code, so we now rely on patch [1].
> 
> [1]: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ee040cbd6e48
> 
> Patch series based on Ted’s latest dev branch.
> 
> `kvm-xfstests -c ext4/all -g auto` has been executed with no new failures.
> `kvm-xfstests -c ext4/32k -g auto` has been executed with no new failures.
> `kvm-xfstests -c ext4/64k -g auto` has been executed with no new failures,
> but allocation failures for large folios may trigger warn_alloc() warnings,
> tests with 32k or smaller block sizes have not exhibited any page allocation
> failures.
> 
> Here are some performance test data for your reference:
> 
> Testing EXT4 filesystems with different block sizes, measuring
> single-threaded dd bandwidth for BIO/DIO with varying bs values.
> 
> Before(PAGE_SIZE=4096):
> 
>       BIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
> --------------|----------|----------|----------|----------|------------
>  4k           | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>  8k (bigalloc)| 1.4 GB/s | 2.0 GB/s | 2.6 GB/s | 3.1 GB/s | 3.4 GB/s
>  16k(bigalloc)| 1.5 GB/s | 2.0 GB/s | 2.6 GB/s | 3.2 GB/s | 3.6 GB/s
>  32k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.7 GB/s | 3.3 GB/s | 3.7 GB/s
>  64k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>               
>       DIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
> --------------|----------|----------|----------|----------|------------
>  4k           | 194 MB/s | 366 MB/s | 626 MB/s | 1.0 GB/s | 1.4 GB/s
>  8k (bigalloc)| 188 MB/s | 359 MB/s | 612 MB/s | 996 MB/s | 1.4 GB/s
>  16k(bigalloc)| 208 MB/s | 378 MB/s | 642 MB/s | 1.0 GB/s | 1.4 GB/s
>  32k(bigalloc)| 184 MB/s | 368 MB/s | 637 MB/s | 995 MB/s | 1.4 GB/s
>  64k(bigalloc)| 208 MB/s | 389 MB/s | 634 MB/s | 1.0 GB/s | 1.4 GB/s
> 
> Patched(PAGE_SIZE=4096):
> 
>    BIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
> ---------|----------|----------|----------|----------|------------
>  4k      | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>  8k (LBS)| 1.7 GB/s | 2.3 GB/s | 3.2 GB/s | 4.2 GB/s | 4.7 GB/s
>  16k(LBS)| 2.0 GB/s | 2.7 GB/s | 3.6 GB/s | 4.7 GB/s | 5.4 GB/s
>  32k(LBS)| 2.2 GB/s | 3.1 GB/s | 3.9 GB/s | 4.9 GB/s | 5.7 GB/s
>  64k(LBS)| 2.4 GB/s | 3.3 GB/s | 4.2 GB/s | 5.1 GB/s | 6.0 GB/s
> 
>    DIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
> ---------|----------|----------|----------|----------|------------
>  4k      | 204 MB/s | 355 MB/s | 627 MB/s | 1.0 GB/s | 1.4 GB/s
>  8k (LBS)| 210 MB/s | 356 MB/s | 602 MB/s | 997 MB/s | 1.4 GB/s
>  16k(LBS)| 191 MB/s | 361 MB/s | 589 MB/s | 981 MB/s | 1.4 GB/s
>  32k(LBS)| 181 MB/s | 330 MB/s | 581 MB/s | 951 MB/s | 1.3 GB/s
>  64k(LBS)| 148 MB/s | 272 MB/s | 499 MB/s | 840 MB/s | 1.3 GB/s
> 
> 
> The results show:
> 
>  * The code changes have almost no impact on the original 4k write
>    performance of ext4.
>  * Compared with bigalloc, LBS improves BIO write performance by about 50%
>    on average.
>  * Compared with bigalloc, LBS shows degradation in DIO write performance,
>    which increases as the filesystem block size grows and the test bs
>    decreases, with a maximum degradation of about 30%.
> 
> The DIO regression is primarily due to the increased time spent in
> crc32c_arch() within ext4_block_bitmap_csum_set() during block allocation,
> as the block size grows larger. This indicates that larger filesystem block
> sizes are not always better; please choose an appropriate block size based
> on your I/O workload characteristics.
> 
> We are also planning further optimizations for block allocation under LBS
> in the future.
> 
> Comments and questions are, as always, welcome.
> 
> Thanks,
> Baokun

Hi Baokun,

I've gone throught the series and the changes look mostly straight
forward to me. I've started running some regression tests on my PowerPC
machine. It's 64k pgsz so I can only test upto bs == ps, but everything
looks normal for now. I'll report here if there are any regressions.

Regardless, feel free to add:
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Thanks,
Ojaswin

> 
> 
> Baokun Li (21):
>   ext4: remove page offset calculation in ext4_block_truncate_page()
>   ext4: remove PAGE_SIZE checks for rec_len conversion
>   ext4: make ext4_punch_hole() support large block size
>   ext4: enable DIOREAD_NOLOCK by default for BS > PS as well
>   ext4: introduce s_min_folio_order for future BS > PS support
>   ext4: support large block size in ext4_calculate_overhead()
>   ext4: support large block size in ext4_readdir()
>   ext4: add EXT4_LBLK_TO_B macro for logical block to bytes conversion
>   ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page
>     conversion
>   ext4: support large block size in ext4_mb_load_buddy_gfp()
>   ext4: support large block size in ext4_mb_get_buddy_page_lock()
>   ext4: support large block size in ext4_mb_init_cache()
>   ext4: prepare buddy cache inode for BS > PS with large folios
>   ext4: support large block size in ext4_mpage_readpages()
>   ext4: support large block size in ext4_block_write_begin()
>   ext4: support large block size in mpage_map_and_submit_buffers()
>   ext4: support large block size in mpage_prepare_extent_to_map()
>   ext4: make data=journal support large block size
>   ext4: support verifying data from large folios with fs-verity
>   ext4: add checks for large folio incompatibilities when BS > PS
>   ext4: enable block size larger than page size
> 
> Zhihao Cheng (3):
>   ext4: remove page offset calculation in ext4_block_zero_page_range()
>   ext4: rename 'page' references to 'folio' in multi-block allocator
>   ext4: support large block size in __ext4_block_zero_page_range()
> 
>  fs/ext4/dir.c       |   8 +--
>  fs/ext4/ext4.h      |  26 ++++-----
>  fs/ext4/ext4_jbd2.c |   3 +-
>  fs/ext4/extents.c   |   2 +-
>  fs/ext4/inode.c     | 112 +++++++++++++++---------------------
>  fs/ext4/mballoc.c   | 137 +++++++++++++++++++++++---------------------
>  fs/ext4/namei.c     |   8 +--
>  fs/ext4/readpage.c  |   7 +--
>  fs/ext4/super.c     |  61 ++++++++++++++++----
>  fs/ext4/sysfs.c     |   6 ++
>  fs/ext4/verity.c    |   2 +-
>  11 files changed, 197 insertions(+), 175 deletions(-)
> 
> -- 
> 2.46.1
> 

Re: [PATCH v4 00/24] ext4: enable block size larger than page size

[Baokun Li]

On 2025-11-21 18:26, Ojaswin Mujoo wrote:
> On Fri, Nov 21, 2025 at 05:06:30PM +0800, libaokun@huaweicloud.com wrote:
>> From: Baokun Li <libaokun1@huawei.com>
>>
>> Changes since v3:
>>  * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
>>     (Thank you for your review!)
>>  * Patch 21: Fix lock imbalance in ext4_change_inode_journal_flag.
>>     (Suggested by Dan Carpenter)
>>
>> [v3]: https://lore.kernel.org/r/20251111142634.3301616-1-libaokun@huaweicloud.com
>>
>> Changes since v2:
>>  * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
>>     (Thank you for your review!)
>>  * Patch 21: Before switching the inode journalling mode, drop all
>>     page cache of that inode and invoke filemap_write_and_wait()
>>     unconditionally. (Suggested by Jan Kara)
>>  * Patch 22: Extend fs-verity to support large folios in addition to
>>     large block size. (Suggested by Jan Kara)
>>  * Patch 24: Add a blocksize_gt_pagesize sysfs interface to help users
>>     (e.g., mke2fs) determine whether the current kernel supports bs > ps.
>>     In addition, remove the experimental tag. (Suggested by Theodore Ts'o)
>>
>> [v2]: https://lore.kernel.org/r/20251107144249.435029-1-libaokun@huaweicloud.com
>>
>> Changes since v1:
>>  * Collect RVB from Jan Kara and Zhang Yi. (Thanks for your review!)
>>  * Patch 4: Just use blocksize in the rounding.(Suggested by Jan Kara)
>>  * Patch 7: use kvmalloc() instead of allocating contiguous physical
>>     pages.(Suggested by Jan Kara)
>>  * Patch 12: Fix some typos.(Suggested by Jan Kara)
>>  * Use clearer naming: EXT4_LBLK_TO_PG() and EXT4_PG_TO_LBLK().
>>     (Suggested by Jan Kara)
>>  * Patch 21: removed. After rebasing on Ted’s latest dev branch, this
>>     patch is no longer needed.
>>  * Patch 22-23: removed. The issue was resolved by removing the WARN_ON
>>     in the MM code, so we now rely on patch [1].(Suggested by Matthew)
>>  * Add new Patch 21 to support data=journal under LBS. (Suggested by
>>     Jan Kara)
>>  * Add new Patch 22 to support fs verity under LBS.
>>  * New Patch 23: add the s_max_folio_order field instead of introducing
>>     the EXT4_MF_LARGE_FOLIO flag.
>>  * New Patch 24: rebase adaptation.
>>
>> [v1]: https://lore.kernel.org/r/20251025032221.2905818-1-libaokun@huaweicloud.com
>>
>> ======
>>
>> This series enables block size > page size (Large Block Size) in EXT4.
>>
>> Since large folios are already supported for regular files, the required
>> changes are not substantial, but they are scattered across the code.
>> The changes primarily focus on cleaning up potential division-by-zero
>> errors, resolving negative left/right shifts, and correctly handling
>> mutually exclusive mount options.
>>
>> One somewhat troublesome issue is that allocating page units greater than
>> order-1 with __GFP_NOFAIL in __alloc_pages_slowpath() can trigger an
>> unexpected WARN_ON. With LBS support, EXT4 and jbd2 may use __GFP_NOFAIL
>> to allocate large folios when reading metadata. The issue was resolved by
>> removing the WARN_ON in the MM code, so we now rely on patch [1].
>>
>> [1]: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ee040cbd6e48
>>
>> Patch series based on Ted’s latest dev branch.
>>
>> `kvm-xfstests -c ext4/all -g auto` has been executed with no new failures.
>> `kvm-xfstests -c ext4/32k -g auto` has been executed with no new failures.
>> `kvm-xfstests -c ext4/64k -g auto` has been executed with no new failures,
>> but allocation failures for large folios may trigger warn_alloc() warnings,
>> tests with 32k or smaller block sizes have not exhibited any page allocation
>> failures.
>>
>> Here are some performance test data for your reference:
>>
>> Testing EXT4 filesystems with different block sizes, measuring
>> single-threaded dd bandwidth for BIO/DIO with varying bs values.
>>
>> Before(PAGE_SIZE=4096):
>>
>>       BIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
>> --------------|----------|----------|----------|----------|------------
>>  4k           | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>>  8k (bigalloc)| 1.4 GB/s | 2.0 GB/s | 2.6 GB/s | 3.1 GB/s | 3.4 GB/s
>>  16k(bigalloc)| 1.5 GB/s | 2.0 GB/s | 2.6 GB/s | 3.2 GB/s | 3.6 GB/s
>>  32k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.7 GB/s | 3.3 GB/s | 3.7 GB/s
>>  64k(bigalloc)| 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>>               
>>       DIO     | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
>> --------------|----------|----------|----------|----------|------------
>>  4k           | 194 MB/s | 366 MB/s | 626 MB/s | 1.0 GB/s | 1.4 GB/s
>>  8k (bigalloc)| 188 MB/s | 359 MB/s | 612 MB/s | 996 MB/s | 1.4 GB/s
>>  16k(bigalloc)| 208 MB/s | 378 MB/s | 642 MB/s | 1.0 GB/s | 1.4 GB/s
>>  32k(bigalloc)| 184 MB/s | 368 MB/s | 637 MB/s | 995 MB/s | 1.4 GB/s
>>  64k(bigalloc)| 208 MB/s | 389 MB/s | 634 MB/s | 1.0 GB/s | 1.4 GB/s
>>
>> Patched(PAGE_SIZE=4096):
>>
>>    BIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
>> ---------|----------|----------|----------|----------|------------
>>  4k      | 1.5 GB/s | 2.1 GB/s | 2.8 GB/s | 3.4 GB/s | 3.8 GB/s
>>  8k (LBS)| 1.7 GB/s | 2.3 GB/s | 3.2 GB/s | 4.2 GB/s | 4.7 GB/s
>>  16k(LBS)| 2.0 GB/s | 2.7 GB/s | 3.6 GB/s | 4.7 GB/s | 5.4 GB/s
>>  32k(LBS)| 2.2 GB/s | 3.1 GB/s | 3.9 GB/s | 4.9 GB/s | 5.7 GB/s
>>  64k(LBS)| 2.4 GB/s | 3.3 GB/s | 4.2 GB/s | 5.1 GB/s | 6.0 GB/s
>>
>>    DIO   | bs=4k    | bs=8k    | bs=16k   | bs=32k   | bs=64k
>> ---------|----------|----------|----------|----------|------------
>>  4k      | 204 MB/s | 355 MB/s | 627 MB/s | 1.0 GB/s | 1.4 GB/s
>>  8k (LBS)| 210 MB/s | 356 MB/s | 602 MB/s | 997 MB/s | 1.4 GB/s
>>  16k(LBS)| 191 MB/s | 361 MB/s | 589 MB/s | 981 MB/s | 1.4 GB/s
>>  32k(LBS)| 181 MB/s | 330 MB/s | 581 MB/s | 951 MB/s | 1.3 GB/s
>>  64k(LBS)| 148 MB/s | 272 MB/s | 499 MB/s | 840 MB/s | 1.3 GB/s
>>
>>
>> The results show:
>>
>>  * The code changes have almost no impact on the original 4k write
>>    performance of ext4.
>>  * Compared with bigalloc, LBS improves BIO write performance by about 50%
>>    on average.
>>  * Compared with bigalloc, LBS shows degradation in DIO write performance,
>>    which increases as the filesystem block size grows and the test bs
>>    decreases, with a maximum degradation of about 30%.
>>
>> The DIO regression is primarily due to the increased time spent in
>> crc32c_arch() within ext4_block_bitmap_csum_set() during block allocation,
>> as the block size grows larger. This indicates that larger filesystem block
>> sizes are not always better; please choose an appropriate block size based
>> on your I/O workload characteristics.
>>
>> We are also planning further optimizations for block allocation under LBS
>> in the future.
>>
>> Comments and questions are, as always, welcome.
>>
>> Thanks,
>> Baokun
> Hi Baokun,
>
> I've gone throught the series and the changes look mostly straight
> forward to me. I've started running some regression tests on my PowerPC
> machine. It's 64k pgsz so I can only test upto bs == ps, but everything
> looks normal for now. I'll report here if there are any regressions.
>
> Regardless, feel free to add:
> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Thank you for your review and testing!


Cheers,
Baokun

Re: [PATCH v4 00/24] ext4: enable block size larger than page size

[Theodore Ts'o]

On Fri, 21 Nov 2025 17:06:30 +0800, libaokun@huaweicloud.com wrote:
> Changes since v3:
>  * Collect RVB from Jan Kara, Zhang Yi and Pankaj Raghav.
>     (Thank you for your review!)
>  * Patch 21: Fix lock imbalance in ext4_change_inode_journal_flag.
>     (Suggested by Dan Carpenter)
> 
> [v3]: https://lore.kernel.org/r/20251111142634.3301616-1-libaokun@huaweicloud.com
> 
> [...]

Applied, thanks!

[01/24] ext4: remove page offset calculation in ext4_block_zero_page_range()
        commit: 5835b1339e33549d9e7342fae56243b4fcd758c9
[02/24] ext4: remove page offset calculation in ext4_block_truncate_page()
        commit: b73f45a32420a8393e92fb2dec3b7d109e565127
[03/24] ext4: remove PAGE_SIZE checks for rec_len conversion
        commit: afa6d5a16bf2e354e183a4fcbcdb8578798e9942
[04/24] ext4: make ext4_punch_hole() support large block size
        commit: d37a7ddd3a384bd34f985273d6e776d3d50b0edd
[05/24] ext4: enable DIOREAD_NOLOCK by default for BS > PS as well
        commit: 58297412edf077870eedce2481db5755b4e98474
[06/24] ext4: introduce s_min_folio_order for future BS > PS support
        commit: 8611e608a8fa01e8b82c9008b4dac9f24531ae0f
[07/24] ext4: support large block size in ext4_calculate_overhead()
        commit: 6a28b5c9908d6e7ea13eae7a5872e8e081a397c4
[08/24] ext4: support large block size in ext4_readdir()
        commit: 609c5e0081b432caaa557ffcf1318aefe1187c4e
[09/24] ext4: add EXT4_LBLK_TO_B macro for logical block to bytes conversion
        commit: 125d1f6a5a77ed6a1af3eb0957240f54e4124af2
[10/24] ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page conversion
        commit: 2a8de76b2b0f84333a2778db04ce51811c260d9d
[11/24] ext4: support large block size in ext4_mb_load_buddy_gfp()
        commit: 6117f1806a7328e8d316eeeac66b2ba4e4539ba5
[12/24] ext4: support large block size in ext4_mb_get_buddy_page_lock()
        commit: 3938fc29f89fff132929b2fea2fe00b0f43617ca
[13/24] ext4: support large block size in ext4_mb_init_cache()
        commit: 0ad55fa104a2aa5980c12f88546fab328d34644b
[14/24] ext4: prepare buddy cache inode for BS > PS with large folios
        commit: 31daa8261c54404513cf7ac81d1f79ff1cdbc36e
[15/24] ext4: rename 'page' references to 'folio' in multi-block allocator
        commit: 65c39954bb92b3f2ab5fb179225b8c8788c79afd
[16/24] ext4: support large block size in ext4_mpage_readpages()
        commit: a6d73242b8b5caa9f9a529eab49cc1e85ace9890
[17/24] ext4: support large block size in ext4_block_write_begin()
        commit: bff6235d623a022260b8af5559ced3534fb7fc2e
[18/24] ext4: support large block size in mpage_map_and_submit_buffers()
        commit: b967ab748765bf2cf9512efaa8aa987ab4482c7d
[19/24] ext4: support large block size in mpage_prepare_extent_to_map()
        commit: 8e50e23b769ace4885fc132e6fca2b4343c27fb1
[20/24] ext4: support large block size in __ext4_block_zero_page_range()
        commit: c00a6292d0616c304cb712d823370f1a82f899b2
[21/24] ext4: make data=journal support large block size
        commit: 58fd191f99f3791c6687e98041c89a6477d9f64d
[22/24] ext4: support verifying data from large folios with fs-verity
        commit: 1a3e9e8aa4f72440b00ef6171b4198f82822d679
[23/24] ext4: add checks for large folio incompatibilities when BS > PS
        commit: 709f0f1f1bf5ca62a000084e5446ca6b57c8678c
[24/24] ext4: enable block size larger than page size
        commit: cab8cbcb923a89cb583c9088fa50431eb2feded5

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>