On Wednesday, February 20, 2019 4:56:49 AM IST Eric Biggers wrote:
> 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;
>
You are right.
> > +
> > 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.
Yes, My plan was to get review comments about the current approach and then
make corresponding changes in F2FS.
>
> >
> > 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?
>
Yes, you are right about that. I will fix it in the next iteration of the
patchset.
> > #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
>
> - Eric
>
>
--
chandan
