On Fri, Jun 07, 2024 at 06:18:29PM +0800, Chao Yu wrote:
> @@ -1990,6 +1989,12 @@ static inline struct f2fs_super_block
> *F2FS_RAW_SUPER(struct f2fs_sb_info *sbi)
> return (struct f2fs_super_block *)(sbi->raw_super);
> }
>
> +static inline struct f2fs_super_block *F2FS_SUPER_BLOCK(struct folio *folio)
> +{
> + return (struct f2fs_super_block *)(page_address(folio_page(folio, 0)) +
> + F2FS_SUPER_OFFSET);
> +}
This assumes that the superblock is in the first page of the folio.
That's not necessarily guaranteed; let's say you have a 64KiB folio
that covers the start of the bdev.
I don't quite know how to write this because f2fs defines its block size
in terms of PAGE_SIZE, which just seems like nonsense to me. If you
format a filesystem on a 16KiB PAGE_SIZE machine and then try to mount
it on a machine with a 4KiB PAGE_SIZE, it's going to go horribly wrong.
You'd need to pass in something that indicates whether you're trying to
access the first or second superblock; there's no way to tell from the
folio which one it is.
> +static int __f2fs_commit_super(struct f2fs_sb_info *sbi, struct folio *folio,
> + 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 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;
> +
> + folio_lock(folio);
> + folio_wait_writeback(folio);
> + if (update)
> + memcpy(F2FS_SUPER_BLOCK(folio), F2FS_RAW_SUPER(sbi),
> + sizeof(struct f2fs_super_block));
> + folio_mark_dirty(folio);
> + folio_clear_dirty_for_io(folio);
> + folio_start_writeback(folio);
> + folio_unlock(folio);
> +
> + 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(folio_index(folio));
> +
> + if (!bio_add_folio(bio, folio, PAGE_SIZE, 0))
> + f2fs_bug_on(sbi, 1);
Better make that folio_size(folio) to support bs>PS.
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