Re: [PATCH 2/3] ext4: introduce ext4_error_remove_page

[Jan Kara]

On Thu 25-10-12 11:12:48, Naoya Horiguchi wrote:
> Ext4 has its own configurable error handling policy, so it's helpful
> if we can use it also in the context of memory error handling.
> With this patch, when we detect a memory error on a dirty pagecache in
> ext4 filesystem, we can allow users to choose to trigger kernel panic
> to avoid consuming corrupted data.
  OK, I've checked and memory_failure() function guarantees page->mapping
is !NULL. So I'm OK with this patch. You can add:
  Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
>  fs/ext4/inode.c | 35 +++++++++++++++++++++++++++++++----
>  1 file changed, 31 insertions(+), 4 deletions(-)
> 
> diff --git v3.7-rc2.orig/fs/ext4/inode.c v3.7-rc2/fs/ext4/inode.c
> index b3c243b..513badb 100644
> --- v3.7-rc2.orig/fs/ext4/inode.c
> +++ v3.7-rc2/fs/ext4/inode.c
> @@ -3163,6 +3163,33 @@ static int ext4_journalled_set_page_dirty(struct page *page)
>  	return __set_page_dirty_nobuffers(page);
>  }
>  
> +static int ext4_error_remove_page(struct address_space *mapping,
> +				struct page *page)
> +{
> +	struct inode *inode = mapping->host;
> +	struct buffer_head *bh, *head;
> +	ext4_fsblk_t block;
> +
> +	if (!PageDirty(page) || !page_has_buffers(page))
> +		goto remove_page;
> +
> +	/* Lost data. Handle as critical fs error. */
> +	bh = head = page_buffers(page);
> +	do {
> +		if (buffer_dirty(bh) && !buffer_delay(bh)) {
> +			block = bh->b_blocknr;
> +			EXT4_ERROR_INODE_BLOCK(inode, block,
> +						"Removing dirty pagecache page");
> +		} else
> +			EXT4_ERROR_INODE(inode,
> +					"Removing dirty pagecache page");
> +		bh = bh->b_this_page;
> +	} while (bh != head);
> +
> +remove_page:
> +	return generic_error_remove_page(mapping, page);
> +}
> +
>  static const struct address_space_operations ext4_ordered_aops = {
>  	.readpage		= ext4_readpage,
>  	.readpages		= ext4_readpages,
> @@ -3175,7 +3202,7 @@ static const struct address_space_operations ext4_ordered_aops = {
>  	.direct_IO		= ext4_direct_IO,
>  	.migratepage		= buffer_migrate_page,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
> -	.error_remove_page	= generic_error_remove_page,
> +	.error_remove_page	= ext4_error_remove_page,
>  };
>  
>  static const struct address_space_operations ext4_writeback_aops = {
> @@ -3190,7 +3217,7 @@ static const struct address_space_operations ext4_writeback_aops = {
>  	.direct_IO		= ext4_direct_IO,
>  	.migratepage		= buffer_migrate_page,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
> -	.error_remove_page	= generic_error_remove_page,
> +	.error_remove_page	= ext4_error_remove_page,
>  };
>  
>  static const struct address_space_operations ext4_journalled_aops = {
> @@ -3205,7 +3232,7 @@ static const struct address_space_operations ext4_journalled_aops = {
>  	.releasepage		= ext4_releasepage,
>  	.direct_IO		= ext4_direct_IO,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
> -	.error_remove_page	= generic_error_remove_page,
> +	.error_remove_page	= ext4_error_remove_page,
>  };
>  
>  static const struct address_space_operations ext4_da_aops = {
> @@ -3221,7 +3248,7 @@ static const struct address_space_operations ext4_da_aops = {
>  	.direct_IO		= ext4_direct_IO,
>  	.migratepage		= buffer_migrate_page,
>  	.is_partially_uptodate  = block_is_partially_uptodate,
> -	.error_remove_page	= generic_error_remove_page,
> +	.error_remove_page	= ext4_error_remove_page,
>  };
>  
>  void ext4_set_aops(struct inode *inode)
> -- 
> 1.7.11.7
> 
-- 
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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