Hi Chandan,
On Mon, Feb 18, 2019 at 03:34:28PM +0530, Chandan Rajendra wrote:
> Ext4 and F2FS store verity metadata in data extents (beyond
> inode->i_size) associated with a file. But other filesystems might
> choose alternative means to store verity metadata. Hence this commit
> adds a callback function pointer to 'struct fsverity_operations' to help
> in deciding if verity operation needs to performed against a page-cache
> page holding file data.
>
> Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxx>
> ---
> fs/ext4/super.c | 9 +++++++++
> fs/post_read_process.c | 5 +++--
> include/linux/fsverity.h | 1 +
> 3 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 9314dddfbf34..2d7781ab6824 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1428,10 +1428,19 @@ static struct page *ext4_read_verity_metadata_page(struct inode *inode,
> return read_mapping_page(inode->i_mapping, index, NULL);
> }
>
> +static bool ext4_verity_required(struct inode *inode, pgoff_t index)
> +{
> + if (index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT))
> + return true;
> + else
> + return false;
> +}
This can be simplified to:
return index < (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +
> static const struct fsverity_operations ext4_verityops = {
> .set_verity = ext4_set_verity,
> .get_metadata_end = ext4_get_verity_metadata_end,
> .read_metadata_page = ext4_read_verity_metadata_page,
> + .verity_required = ext4_verity_required,
> };
> #endif /* CONFIG_FS_VERITY */
Doesn't f2fs need this too? This patch only changes ext4.
>
> diff --git a/fs/post_read_process.c b/fs/post_read_process.c
> index 9720eeff0160..1f8663d70247 100644
> --- a/fs/post_read_process.c
> +++ b/fs/post_read_process.c
> @@ -79,8 +79,9 @@ struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
> if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
> post_read_steps |= 1 << STEP_DECRYPT;
> #ifdef CONFIG_FS_VERITY
> - if (inode->i_verity_info != NULL &&
> - (index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
> + if (inode->i_verity_info != NULL
> + && inode->i_sb->s_vop->verity_required
> + && inode->i_sb->s_vop->verity_required(inode, index))
> post_read_steps |= 1 << STEP_VERITY;
If ->verity_required is NULL, shouldn't that be equivalent to
->verity_required() returning true?
> #endif
> if (post_read_steps) {
> diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
> index 7c33b42abf1b..b83712d6c79a 100644
> --- a/include/linux/fsverity.h
> +++ b/include/linux/fsverity.h
> @@ -18,6 +18,7 @@ struct fsverity_operations {
> int (*set_verity)(struct inode *inode, loff_t data_i_size);
> int (*get_metadata_end)(struct inode *inode, loff_t *metadata_end_ret);
> struct page *(*read_metadata_page)(struct inode *inode, pgoff_t index);
> + bool (*verity_required)(struct inode *inode, pgoff_t index);
> };
>
> #ifdef CONFIG_FS_VERITY
> --
> 2.19.1
>
- Eric
