Re: [f2fs-dev] [PATCH 4/4] f2fs: fix inline data not being written to disk in writeback path

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

On 2026/2/3 21:37, Yongpeng Yang wrote:
> From: Yongpeng Yang <yangyongpeng@xiaomi.com>
> 
> When f2fs_fiemap() is called with `fileinfo->fi_flags` containing the
> FIEMAP_FLAG_SYNC flag, it attempts to write data to disk before

Can we fix this in f2fs_fiemap()? rather than in f2fs_write_single_data_page(),
since it affects more.

f2fs_inline_data_fiemap()
...

if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
	write single node page if it is dirty?

Thanks,

> retrieving file mappings via filemap_write_and_wait(). However, there is
> an issue where the file does not get mapped as expected. The following
> scenario can occur:
> 
> root@vm:/mnt/f2fs# dd if=/dev/zero of=data.3k bs=3k count=1
> root@vm:/mnt/f2fs# xfs_io data.3k -c "fiemap -v 0 4096"
> data.3k:
>   EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
>     0: [0..5]:          0..5                 6 0x307
> 
> The root cause of this issue is that f2fs_write_single_data_page() only
> calls f2fs_write_inline_data() to copy data from the data folio to the
> inode folio, and it clears the dirty flag on the data folio. However, it
> does not mark the data folio as writeback. When
> __filemap_fdatawait_range() checks for folios with the writeback flag,
> it returns early, causing f2fs_fiemap() to report that the file has no
> mapping.
> 
> To fix this issue, the solution is to call f2fs_sync_node_pages() after
> f2fs_write_inline_data() successfully returns, which will write back the
> inode folio and wait for the writeback to complete.
> 
> Fixes: 9ffe0fb5f3bb ("f2fs: handle inline data operations")
> Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
> ---
>   fs/f2fs/checkpoint.c |  1 +
>   fs/f2fs/data.c       | 19 ++++++++++++++++++-
>   fs/f2fs/node.c       | 21 ++++++++++++++++-----
>   3 files changed, 35 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 5172396c0b01..d0bca57854da 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -1347,6 +1347,7 @@ static int block_operations(struct f2fs_sb_info *sbi)
>   	struct writeback_control wbc = {
>   		.sync_mode = WB_SYNC_ALL,
>   		.nr_to_write = LONG_MAX,
> +		.range_cyclic = 1,
>   	};
>   	int err = 0, cnt = 0;
>   
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index eedadccf86bb..ccc5e4ddf547 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3126,8 +3126,25 @@ int f2fs_write_single_data_page(struct folio *folio, int *submitted,
>   	err = -EAGAIN;
>   	if (f2fs_has_inline_data(inode)) {
>   		err = f2fs_write_inline_data(inode, folio);
> -		if (!err)
> +		if (!err) {
> +			struct folio *ifolio;
> +			struct writeback_control iwbc = {
> +				.sync_mode = WB_SYNC_ALL,
> +				.range_start = inode->i_ino << PAGE_SHIFT,
> +				.range_end = inode->i_ino << PAGE_SHIFT,
> +				.nr_to_write = 1,
> +				.range_cyclic = 0,
> +			};
> +
> +			if (!f2fs_sync_node_pages(sbi, &iwbc, true, FS_NODE_IO)) {
> +				ifolio = f2fs_get_inode_folio(sbi, inode->i_ino);
> +				if (!IS_ERR(ifolio)) {
> +					f2fs_folio_wait_writeback(ifolio, NODE, true, true);
> +					f2fs_folio_put(ifolio, true);
> +				}
> +			}
>   			goto out;
> +		}
>   	}
>   
>   	if (err == -EAGAIN) {
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 74992fd9c9b6..47bff89bafe6 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -2083,7 +2083,8 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
>   				struct writeback_control *wbc,
>   				bool do_balance, enum iostat_type io_type)
>   {
> -	pgoff_t index;
> +	pgoff_t index, wbc_index;
> +	pgoff_t end, wbc_end;
>   	struct folio_batch fbatch;
>   	int step = 0;
>   	int nwritten = 0;
> @@ -2092,14 +2093,24 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
>   
>   	folio_batch_init(&fbatch);
>   
> +	wbc_index = 0;
> +	wbc_end = LONG_MAX;
> +	if (!wbc->range_cyclic) {
> +		wbc_index = wbc->range_start >> PAGE_SHIFT;
> +		wbc_end = wbc->range_end >> PAGE_SHIFT;
> +	}
>   next_step:
> -	index = 0;
> +	index = wbc_index;
> +	end = wbc_end;
>   
> -	while (!done && (nr_folios = filemap_get_folios_tag(NODE_MAPPING(sbi),
> -				&index, (pgoff_t)-1, PAGECACHE_TAG_DIRTY,
> -				&fbatch))) {
> +	while (!done && (index <= end)) {
>   		int i;
>   
> +		nr_folios = filemap_get_folios_tag(NODE_MAPPING(sbi),
> +				&index, end, PAGECACHE_TAG_DIRTY,
> +				&fbatch);
> +		if (nr_folios == 0)
> +			break;
>   		for (i = 0; i < nr_folios; i++) {
>   			struct folio *folio = fbatch.folios[i];
>   			bool submitted = false;



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