[f2fs-dev] [PATCH] f2fs: get rid of buffer_head use

[f2fs-dev] [PATCH] f2fs: get rid of buffer_head use

[Chao Yu]

For later folio conversion.

Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Chao Yu <chao@kernel.org>
---
v1:
- I checked recovery flow of superblock w/ below testcase, it passes.
1. mkfs.f2fs /dev/vdd
2. dd if=/dev/zero of=/dev/vdd bs=4k count=1
3. mount /dev/vdd /mnt/f2fs
4. umount /mnt/f2fs
5. dd if=/dev/zero of=/dev/vdd bs=4k count=1 seek=1
6. mount /dev/vdd /mnt/f2fs
7. umount /mnt/f2fs

 fs/f2fs/data.c  |  1 -
 fs/f2fs/f2fs.h  |  1 -
 fs/f2fs/file.c  |  1 -
 fs/f2fs/inode.c |  1 -
 fs/f2fs/super.c | 95 ++++++++++++++++++++++++++++++-------------------
 5 files changed, 58 insertions(+), 41 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b9b0debc6b3d..ad495ea87b32 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -7,7 +7,6 @@
  */
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
-#include <linux/buffer_head.h>
 #include <linux/sched/mm.h>
 #include <linux/mpage.h>
 #include <linux/writeback.h>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9688df332147..5ed6b689f6b3 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -11,7 +11,6 @@
 #include <linux/uio.h>
 #include <linux/types.h>
 #include <linux/page-flags.h>
-#include <linux/buffer_head.h>
 #include <linux/slab.h>
 #include <linux/crc32.h>
 #include <linux/magic.h>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index c50213da474d..efc676bc7800 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -8,7 +8,6 @@
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
 #include <linux/stat.h>
-#include <linux/buffer_head.h>
 #include <linux/writeback.h>
 #include <linux/blkdev.h>
 #include <linux/falloc.h>
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index dbfebbddf675..87982e06bbe7 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -7,7 +7,6 @@
  */
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
-#include <linux/buffer_head.h>
 #include <linux/writeback.h>
 #include <linux/sched/mm.h>
 #include <linux/lz4.h>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 4a1bc8f40f9a..e67f0ac78c00 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -11,7 +11,6 @@
 #include <linux/fs_context.h>
 #include <linux/sched/mm.h>
 #include <linux/statfs.h>
-#include <linux/buffer_head.h>
 #include <linux/kthread.h>
 #include <linux/parser.h>
 #include <linux/mount.h>
@@ -3333,24 +3332,45 @@ loff_t max_file_blocks(struct inode *inode)
 	return result;
 }
 
-static int __f2fs_commit_super(struct buffer_head *bh,
-			struct f2fs_super_block *super)
+static int __f2fs_commit_super(struct f2fs_sb_info *sbi, struct page *page,
+								bool update)
 {
-	lock_buffer(bh);
-	if (super)
-		memcpy(bh->b_data + F2FS_SUPER_OFFSET, super, sizeof(*super));
-	set_buffer_dirty(bh);
-	unlock_buffer(bh);
-
+	struct f2fs_super_block *super;
+	struct bio *bio;
 	/* it's rare case, we can do fua all the time */
-	return __sync_dirty_buffer(bh, REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
+	blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH | REQ_FUA;
+	int ret;
+
+	lock_page(page);
+	if (update) {
+		super = F2FS_RAW_SUPER(sbi);
+		memcpy(page_address(page) + F2FS_SUPER_OFFSET,
+						super, sizeof(*super));
+	}
+	set_page_dirty(page);
+	clear_page_dirty_for_io(page);
+	set_page_writeback(page);
+	unlock_page(page);
+
+	bio = bio_alloc(sbi->sb->s_bdev, 1, opf, GFP_NOFS);
+
+	/* it doesn't need to set crypto context for superblock update */
+	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(page->index);
+
+	if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE)
+		f2fs_bug_on(sbi, 1);
+
+	ret = submit_bio_wait(bio);
+	end_page_writeback(page);
+
+	return ret;
 }
 
 static inline bool sanity_check_area_boundary(struct f2fs_sb_info *sbi,
-					struct buffer_head *bh)
+							struct page *page)
 {
 	struct f2fs_super_block *raw_super = (struct f2fs_super_block *)
-					(bh->b_data + F2FS_SUPER_OFFSET);
+				(page_address(page) + F2FS_SUPER_OFFSET);
 	struct super_block *sb = sbi->sb;
 	u32 segment0_blkaddr = le32_to_cpu(raw_super->segment0_blkaddr);
 	u32 cp_blkaddr = le32_to_cpu(raw_super->cp_blkaddr);
@@ -3425,7 +3445,7 @@ static inline bool sanity_check_area_boundary(struct f2fs_sb_info *sbi,
 			set_sbi_flag(sbi, SBI_NEED_SB_WRITE);
 			res = "internally";
 		} else {
-			err = __f2fs_commit_super(bh, NULL);
+			err = __f2fs_commit_super(sbi, page, false);
 			res = err ? "failed" : "done";
 		}
 		f2fs_info(sbi, "Fix alignment : %s, start(%u) end(%llu) block(%u)",
@@ -3437,13 +3457,12 @@ static inline bool sanity_check_area_boundary(struct f2fs_sb_info *sbi,
 	return false;
 }
 
-static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
-				struct buffer_head *bh)
+static int sanity_check_raw_super(struct f2fs_sb_info *sbi, struct page *page)
 {
 	block_t segment_count, segs_per_sec, secs_per_zone, segment_count_main;
 	block_t total_sections, blocks_per_seg;
 	struct f2fs_super_block *raw_super = (struct f2fs_super_block *)
-					(bh->b_data + F2FS_SUPER_OFFSET);
+				(page_address(page) + F2FS_SUPER_OFFSET);
 	size_t crc_offset = 0;
 	__u32 crc = 0;
 
@@ -3601,7 +3620,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
 	}
 
 	/* check CP/SIT/NAT/SSA/MAIN_AREA area boundary */
-	if (sanity_check_area_boundary(sbi, bh))
+	if (sanity_check_area_boundary(sbi, page))
 		return -EFSCORRUPTED;
 
 	return 0;
@@ -3948,7 +3967,7 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
 {
 	struct super_block *sb = sbi->sb;
 	int block;
-	struct buffer_head *bh;
+	struct page *page;
 	struct f2fs_super_block *super;
 	int err = 0;
 
@@ -3957,32 +3976,32 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
 		return -ENOMEM;
 
 	for (block = 0; block < 2; block++) {
-		bh = sb_bread(sb, block);
-		if (!bh) {
+		page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping,
+								block, NULL);
+		if (IS_ERR(page)) {
 			f2fs_err(sbi, "Unable to read %dth superblock",
 				 block + 1);
-			err = -EIO;
+			err = PTR_ERR(page);
 			*recovery = 1;
-			continue;
 		}
 
 		/* sanity checking of raw super */
-		err = sanity_check_raw_super(sbi, bh);
+		err = sanity_check_raw_super(sbi, page);
 		if (err) {
 			f2fs_err(sbi, "Can't find valid F2FS filesystem in %dth superblock",
 				 block + 1);
-			brelse(bh);
+			put_page(page);
 			*recovery = 1;
 			continue;
 		}
 
 		if (!*raw_super) {
-			memcpy(super, bh->b_data + F2FS_SUPER_OFFSET,
+			memcpy(super, page_address(page) + F2FS_SUPER_OFFSET,
 							sizeof(*super));
 			*valid_super_block = block;
 			*raw_super = super;
 		}
-		brelse(bh);
+		put_page(page);
 	}
 
 	/* No valid superblock */
@@ -3996,7 +4015,7 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
 
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 {
-	struct buffer_head *bh;
+	struct page *page;
 	__u32 crc = 0;
 	int err;
 
@@ -4014,22 +4033,24 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 	}
 
 	/* write back-up superblock first */
-	bh = sb_bread(sbi->sb, sbi->valid_super_block ? 0 : 1);
-	if (!bh)
-		return -EIO;
-	err = __f2fs_commit_super(bh, F2FS_RAW_SUPER(sbi));
-	brelse(bh);
+	page = read_mapping_page(sbi->sb->s_bdev->bd_inode->i_mapping,
+				sbi->valid_super_block ? 0 : 1, NULL);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	err = __f2fs_commit_super(sbi, page, true);
+	put_page(page);
 
 	/* if we are in recovery path, skip writing valid superblock */
 	if (recover || err)
 		return err;
 
 	/* write current valid superblock */
-	bh = sb_bread(sbi->sb, sbi->valid_super_block);
-	if (!bh)
-		return -EIO;
-	err = __f2fs_commit_super(bh, F2FS_RAW_SUPER(sbi));
-	brelse(bh);
+	page = read_mapping_page(sbi->sb->s_bdev->bd_inode->i_mapping,
+					sbi->valid_super_block, NULL);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	err = __f2fs_commit_super(sbi, page, true);
+	put_page(page);
 	return err;
 }
 
-- 
2.40.1



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Re: [f2fs-dev] [PATCH] f2fs: get rid of buffer_head use

[Matthew Wilcox]

On Thu, Jun 06, 2024 at 05:50:37PM +0800, Chao Yu wrote:
> For later folio conversion.

What tree is this against?

> @@ -3957,32 +3976,32 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
>  		return -ENOMEM;
>  
>  	for (block = 0; block < 2; block++) {
> -		bh = sb_bread(sb, block);
> -		if (!bh) {
> +		page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping,
> +								block, NULL);

You need to use bd_mapping, not bd_inode->i_mapping (since May 21 in
Linus' tree).

And I don't think there's much point in switching to pages as an
intermediate step.  You may as well go straight to folios.

		folio = read_mapping_folio(sb->s_bdev->bd_mapping, block, NULL);



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Re: [f2fs-dev] [PATCH] f2fs: get rid of buffer_head use

[Chao Yu]

On 2024/6/6 20:38, Matthew Wilcox wrote:
> On Thu, Jun 06, 2024 at 05:50:37PM +0800, Chao Yu wrote:
>> For later folio conversion.
> 
> What tree is this against?

Last dev-test branch of f2fs git tree, I guess it's a little behind
to linus' tree.

> 
>> @@ -3957,32 +3976,32 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
>>   		return -ENOMEM;
>>   
>>   	for (block = 0; block < 2; block++) {
>> -		bh = sb_bread(sb, block);
>> -		if (!bh) {
>> +		page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping,
>> +								block, NULL);
> 
> You need to use bd_mapping, not bd_inode->i_mapping (since May 21 in
> Linus' tree).

Will update it once f2fs codebase was rebased to linus' tree.

> 
> And I don't think there's much point in switching to pages as an
> intermediate step.  You may as well go straight to folios.
> 
> 		folio = read_mapping_folio(sb->s_bdev->bd_mapping, block, NULL);

Fine, let me work on this in v2.

Thanks,

> 


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