Re: Patch "btrfs: move large data folios out of experimental features" has been added to the 7.1-stable tree

在 2026/8/12 09:37, Sasha Levin 写道:
> This is a note to let you know that I've just added the patch titled
> 
>      btrfs: move large data folios out of experimental features
> 
> to the 7.1-stable tree which can be found at:
>      http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>       btrfs-move-large-data-folios-out-of-experimental-fea.patch
> and it can be found in the queue-7.1 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <[email protected]> know about it.

Please don't merge this new feature into any stable tree.

This feature is not compatible with the COW fixup mechanism in old kernels.

Thanks,
Qu

> 
> 
> 
> commit 3d8483065b9a103c8f10a57dd8638ce0f29b1dba
> Author: Qu Wenruo <[email protected]>
> Date:   Fri Apr 24 10:20:25 2026 +0930
> 
>      btrfs: move large data folios out of experimental features
>      
>      [ Upstream commit 9bce95edb1b4d2802de9273b5170bfcff3090d24 ]
>      
>      This feature was introduced in v6.17 under experimental, and we had
>      several small bugs related to or exposed by that:
>      
>        e9e3b22ddfa7 ("btrfs: fix beyond-EOF write handling")
>        18de34daa7c6 ("btrfs: truncate ordered extent when skipping writeback past i_size")
>      
>      Otherwise, the feature has been frequently tested by btrfs developers.
>      
>      The latest fix only arrived in v6.19. After three releases, I think it's
>      time to move this feature out of experimental.
>      
>      And since we're here, also remove the comment about the bitmap size
>      limit, which is no longer relevant in the context. It will soon be
>      outdated for the incoming huge folio support.
>      
>      Reviewed-by: Neal Gompa <[email protected]>
>      Signed-off-by: Qu Wenruo <[email protected]>
>      Signed-off-by: David Sterba <[email protected]>
>      Stable-dep-of: 4c375ac546ea ("btrfs: disable bs > ps support if no transparent hugepage support")
>      Signed-off-by: Sasha Levin <[email protected]>
> 
> diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
> index 5e75438e0b738..55eba4f1b6c79 100644
> --- a/fs/btrfs/Kconfig
> +++ b/fs/btrfs/Kconfig
> @@ -110,7 +110,7 @@ config BTRFS_EXPERIMENTAL
>   
>   	  - extent tree v2 - complex rework of extent tracking
>   
> -	  - large folio and block size (> page size) support
> +	  - block size > page size support
>   
>   	  - asynchronous checksum generation for data writes
>   
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index beb75f152d5cd..8a802e3675cd8 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -533,12 +533,9 @@ static inline void btrfs_set_inode_mapping_order(struct btrfs_inode *inode)
>   	/* Metadata inode should not reach here. */
>   	ASSERT(is_data_inode(inode));
>   
> -	/* We only allow BITS_PER_LONGS blocks for each bitmap. */
> -#ifdef CONFIG_BTRFS_EXPERIMENTAL
>   	mapping_set_folio_order_range(inode->vfs_inode.i_mapping,
>   				      inode->root->fs_info->block_min_order,
>   				      inode->root->fs_info->block_max_order);
> -#endif
>   }
>   
>   void btrfs_calculate_block_csum_folio(struct btrfs_fs_info *fs_info,
> diff --git a/fs/btrfs/defrag.c b/fs/btrfs/defrag.c
> index 7e2db5d3a4d4c..9111308351f82 100644
> --- a/fs/btrfs/defrag.c
> +++ b/fs/btrfs/defrag.c
> @@ -859,23 +859,6 @@ static struct folio *defrag_prepare_one_folio(struct btrfs_inode *inode, pgoff_t
>   	if (IS_ERR(folio))
>   		return folio;
>   
> -	/*
> -	 * Since we can defragment files opened read-only, we can encounter
> -	 * transparent huge pages here (see CONFIG_READ_ONLY_THP_FOR_FS).
> -	 *
> -	 * The IO for such large folios is not fully tested, thus return
> -	 * an error to reject such folios unless it's an experimental build.
> -	 *
> -	 * Filesystem transparent huge pages are typically only used for
> -	 * executables that explicitly enable them, so this isn't very
> -	 * restrictive.
> -	 */
> -	if (!IS_ENABLED(CONFIG_BTRFS_EXPERIMENTAL) && folio_test_large(folio)) {
> -		folio_unlock(folio);
> -		folio_put(folio);
> -		return ERR_PTR(-ETXTBSY);
> -	}
> -
>   	ret = set_folio_extent_mapped(folio);
>   	if (ret < 0) {
>   		folio_unlock(folio);