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SubjectRe: [PATCH 1/2] vfs: new super block feature flags attribute
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On Thu, 2012-11-22 at 14:49 +0200, Dmitry Kasatkin wrote:
> This patch introduces new super block attribute flag s_feature_flags
> and SF_IMA_DISABLED flag. This flag will be used by Integrity Measurement
> Architecture (IMA). Name suggested by Bruce Fields.

The patch looks good. The patch description should reflect the
discussion with Al https://lkml.org/lkml/2012/9/19/9, explanining 'why'
a new flag is needed.

> Certain file system types and partitions will never be measured or
> appraised by IMA depending on the policy. For example, pseudo file
> systems are never measured and appraised. In current implementation
> policy will be checked again and again. It happens thousands times
> per second. That is absolute waste of CPU and may be battery resources.
>
> IMA will set the SF_IMA_DISABLED flag when file system will not be measured
> and appraised and test this flag during subsequent calls to skip policy search.

This explanation belongs in the subsequent patch, which makes use of the
flag.

> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>


> ---
> include/linux/fs.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index b33cfc9..0bef2b2 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1321,6 +1321,8 @@ struct super_block {
>
> /* Being remounted read-only */
> int s_readonly_remount;
> +
> + unsigned long s_feature_flags;
> };
>
> /* superblock cache pruning functions */
> @@ -1746,6 +1748,8 @@ struct super_operations {
>
> #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
>

Comment needed here before the start of the feature flag definitions.

> +#define SF_IMA_DISABLED 0x0001
> +
> extern void __mark_inode_dirty(struct inode *, int);
> static inline void mark_inode_dirty(struct inode *inode)
> {

thanks,

Mimi



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