On 2019-04-28, at 10:01:11 +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 | 6 ++++++
> fs/f2fs/super.c | 6 ++++++
> fs/read_callbacks.c | 4 +++-
> include/linux/fsverity.h | 1 +
> 4 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index aba724f82cc3..63d73b360f1d 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1428,10 +1428,16 @@ 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)
> +{
> + 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 */
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 2f75f06c784a..cd1299e1f92d 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -2257,10 +2257,16 @@ static struct page *f2fs_read_verity_metadata_page(struct inode *inode,
> return read_mapping_page(inode->i_mapping, index, NULL);
> }
>
> +static bool f2fs_verity_required(struct inode *inode, pgoff_t index)
> +{
> + return index < (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +}
> +
> static const struct fsverity_operations f2fs_verityops = {
> .set_verity = f2fs_set_verity,
> .get_metadata_end = f2fs_get_verity_metadata_end,
> .read_metadata_page = f2fs_read_verity_metadata_page,
> + .verity_required = f2fs_verity_required,
> };
> #endif /* CONFIG_FS_VERITY */
>
> diff --git a/fs/read_callbacks.c b/fs/read_callbacks.c
> index b6d5b95e67d7..6dea54b0baa9 100644
> --- a/fs/read_callbacks.c
> +++ b/fs/read_callbacks.c
> @@ -86,7 +86,9 @@ struct read_callbacks_ctx *get_read_callbacks_ctx(struct inode *inode,
> read_callbacks_steps |= 1 << STEP_DECRYPT;
> #ifdef CONFIG_FS_VERITY
> if (inode->i_verity_info != NULL &&
> - (index < ((i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT)))
> + ((inode->i_sb->s_vop->verity_required
> + && inode->i_sb->s_vop->verity_required(inode, index))
> + || (inode->i_sb->s_vop->verity_required == NULL)))
I think this is a bit easier to follow:
(inode->i_sb->s_vop->verity_required == NULL ||
inode->i_sb->s_vop->verity_required(inode, index)))
> read_callbacks_steps |= 1 << STEP_VERITY;
> #endif
> if (read_callbacks_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
>
>
J.
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