[lustre-devel] [PATCH RFC] lustre: llite: add LL_IOC_FUTIMES_3

[NeilBrown]

On Mon, Nov 26 2018, James Simmons wrote:

> Add a new regular file ioctl LL_IOC_FUTIMES_3 similar to futimes() but
> which allows setting of all three inode timestamps. Use this ioctl
> during HSM restore to ensure that the volatile file has the same
> timestamps as the file to be restored. Strengthen sanity-hsm test_24a
> to check that archive, release, and restore do not change a file's
> ctime. Add sanity-hsm test_24e to check that tar will succeed when it
> encounters a HSM released file.

What is this used for?  What is the minimum functionality that would be
acceptable?

I'm guessing that it is used to migrate files between different levels
in the HSM storage hierarchy.  Why is it important that the ctime not
change?  How is the ctime used in a way that would be confused?
Would it be sufficient, for example, to be able to set the ctime to the
same as the mtime?

I'm imagining adding a flag to utimesat which is privileged and causes
ctime to be set to mtime, instead of to current time.  The justification
would be that it is for restoring from backups in a way that the
restored file doesn't look like it needs backup up immediately - not
even the metadata.

Thanks,
NeilBrown


>
> *******************************************************************
>
> Original pushed this to staging but Greg discussed about making this
> a syscall instead. Andreas brought you this might be of use to other
> file systems like XFS.
>
> *******************************************************************
>
> Signed-off-by: John L. Hammond <jhammond at whamcloud.com>
> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6213
> Reviewed-on: http://review.whamcloud.com/13665
> Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
> Reviewed-by: Jinshan Xiong <jinshan.xiong at gmail.com>
> Reviewed-by: frank zago <fzago at cray.com>
> Reviewed-by: Oleg Drokin <green at whamcloud.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>  .../lustre/include/uapi/linux/lustre/lustre_user.h | 10 +++++
>  drivers/staging/lustre/lustre/llite/file.c         | 46 ++++++++++++++++++++++
>  2 files changed, 56 insertions(+)
>
> diff --git a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
> index 9d553ce6..6904d6d 100644
> --- a/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
> +++ b/drivers/staging/lustre/include/uapi/linux/lustre/lustre_user.h
> @@ -215,6 +215,15 @@ struct ost_id {
>  #define DOSTID "%#llx:%llu"
>  #define POSTID(oi) ostid_seq(oi), ostid_id(oi)
>  
> +struct ll_futimes_3 {
> +	__u64 lfu_atime_sec;
> +	__u64 lfu_atime_nsec;
> +	__u64 lfu_mtime_sec;
> +	__u64 lfu_mtime_nsec;
> +	__u64 lfu_ctime_sec;
> +	__u64 lfu_ctime_nsec;
> +};
> +
>  /*
>   * The ioctl naming rules:
>   * LL_*     - works on the currently opened filehandle instead of parent dir
> @@ -251,6 +260,7 @@ struct ost_id {
>  #define LL_IOC_PATH2FID		 _IOR('f', 173, long)
>  #define LL_IOC_GET_CONNECT_FLAGS	_IOWR('f', 174, __u64 *)
>  #define LL_IOC_GET_MDTIDX	       _IOR('f', 175, int)
> +#define LL_IOC_FUTIMES_3		_IOWR('f', 176, struct ll_futimes_3)
>  
>  /*	lustre_ioctl.h			177-210 */
>  #define LL_IOC_HSM_STATE_GET		_IOR('f', 211, struct hsm_user_state)
> diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
> index 06789ec..aa54aad 100644
> --- a/drivers/staging/lustre/lustre/llite/file.c
> +++ b/drivers/staging/lustre/lustre/llite/file.c
> @@ -2098,6 +2098,42 @@ static inline long ll_lease_type_from_fmode(fmode_t fmode)
>  	       ((fmode & FMODE_WRITE) ? LL_LEASE_WRLCK : 0);
>  }
>  
> +static int ll_file_futimes_3(struct file *file, const struct ll_futimes_3 *lfu)
> +{
> +	struct inode *inode = file_inode(file);
> +	struct iattr ia = {
> +		.ia_valid = ATTR_ATIME | ATTR_ATIME_SET |
> +			    ATTR_MTIME | ATTR_MTIME_SET |
> +			    ATTR_CTIME,
> +		.ia_atime = {
> +			.tv_sec = lfu->lfu_atime_sec,
> +			.tv_nsec = lfu->lfu_atime_nsec,
> +		},
> +		.ia_mtime = {
> +			.tv_sec = lfu->lfu_mtime_sec,
> +			.tv_nsec = lfu->lfu_mtime_nsec,
> +		},
> +		.ia_ctime = {
> +			.tv_sec = lfu->lfu_ctime_sec,
> +			.tv_nsec = lfu->lfu_ctime_nsec,
> +		},
> +	};
> +	int rc;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	if (!S_ISREG(inode->i_mode))
> +		return -EINVAL;
> +
> +	inode_lock(inode);
> +	rc = ll_setattr_raw(file_dentry(file), &ia, OP_XVALID_CTIME_SET,
> +			    false);
> +	inode_unlock(inode);
> +
> +	return rc;
> +}
> +
>  /*
>   * Give file access advices
>   *
> @@ -2552,6 +2588,16 @@ int ll_ioctl_fssetxattr(struct inode *inode, unsigned int cmd,
>  		kfree(hui);
>  		return rc;
>  	}
> +	case LL_IOC_FUTIMES_3: {
> +		const struct ll_futimes_3 __user *lfu_user;
> +		struct ll_futimes_3 lfu;
> +
> +		lfu_user = (const struct ll_futimes_3 __user *)arg;
> +		if (copy_from_user(&lfu, lfu_user, sizeof(lfu)))
> +			return -EFAULT;
> +
> +		return ll_file_futimes_3(file, &lfu);
> +        }
>  	case LL_IOC_LADVISE: {
>  		struct llapi_ladvise_hdr *ladvise_hdr;
>  		int alloc_size = sizeof(*ladvise_hdr);
> -- 
> 1.8.3.1
>
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> lustre-devel mailing list
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> http://lists.lustre.org/listinfo.cgi/lustre-devel-lustre.org
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