ACK: [PATCH][G/Unstable] ext4: implement swap_activate aops using iomap

[Kelsey Skunberg]

Clean cherry pick. lgtm

Acked-by: Kelsey Skunberg <kelsey.skunberg at canonical.com>

On 2020-10-14 15:32:32 , Seth Forshee wrote:
> From: Ritesh Harjani <riteshh at linux.ibm.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1892728
> 
> After moving ext4's bmap to iomap interface, swapon functionality
> on files created using fallocate (which creates unwritten extents) are
> failing. This is since iomap_bmap interface returns 0 for unwritten
> extents and thus generic_swapfile_activate considers this as holes
> and hence bail out with below kernel msg :-
> 
> [340.915835] swapon: swapfile has holes
> 
> To fix this we need to implement ->swap_activate aops in ext4
> which will use ext4_iomap_report_ops. Since we only need to return
> the list of extents so ext4_iomap_report_ops should be enough.
> 
> Reported-by: Yuxuan Shui <yshuiv7 at gmail.com>
> Fixes: ac58e4fb03f ("ext4: move ext4 bmap to use iomap infrastructure")
> Signed-off-by: Ritesh Harjani <riteshh at linux.ibm.com>
> Link: https://lore.kernel.org/r/20200904091653.1014334-1-riteshh@linux.ibm.com
> Signed-off-by: Theodore Ts'o <tytso at mit.edu>
> (cherry picked from commit 424de74af0d0679e99660904a5f472acd85bdb73 linux-next)
> Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
> ---
>  fs/ext4/inode.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 9c0629ffb426..30177c5a9b97 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3601,6 +3601,13 @@ static int ext4_set_page_dirty(struct page *page)
>  	return __set_page_dirty_buffers(page);
>  }
>  
> +static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
> +				    struct file *file, sector_t *span)
> +{
> +	return iomap_swapfile_activate(sis, file, span,
> +				       &ext4_iomap_report_ops);
> +}
> +
>  static const struct address_space_operations ext4_aops = {
>  	.readpage		= ext4_readpage,
>  	.readahead		= ext4_readahead,
> @@ -3616,6 +3623,7 @@ static const struct address_space_operations ext4_aops = {
>  	.migratepage		= buffer_migrate_page,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
>  	.error_remove_page	= generic_error_remove_page,
> +	.swap_activate		= ext4_iomap_swap_activate,
>  };
>  
>  static const struct address_space_operations ext4_journalled_aops = {
> @@ -3632,6 +3640,7 @@ static const struct address_space_operations ext4_journalled_aops = {
>  	.direct_IO		= noop_direct_IO,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
>  	.error_remove_page	= generic_error_remove_page,
> +	.swap_activate		= ext4_iomap_swap_activate,
>  };
>  
>  static const struct address_space_operations ext4_da_aops = {
> @@ -3649,6 +3658,7 @@ static const struct address_space_operations ext4_da_aops = {
>  	.migratepage		= buffer_migrate_page,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
>  	.error_remove_page	= generic_error_remove_page,
> +	.swap_activate		= ext4_iomap_swap_activate,
>  };
>  
>  static const struct address_space_operations ext4_dax_aops = {
> @@ -3657,6 +3667,7 @@ static const struct address_space_operations ext4_dax_aops = {
>  	.set_page_dirty		= noop_set_page_dirty,
>  	.bmap			= ext4_bmap,
>  	.invalidatepage		= noop_invalidatepage,
> +	.swap_activate		= ext4_iomap_swap_activate,
>  };
>  
>  void ext4_set_aops(struct inode *inode)
> -- 
> 2.27.0
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team