Re: [PATCH 4/8] xfs: support project ID in xfs_setattr()

[Dave Chinner <david@fromorbit.com>]

On Fri, Mar 01, 2019 at 11:05:37PM +0900, Wang Shilong wrote:
> From: Wang Shilong <wshilong@ddn.com>
> 
> From: Wang Shilong <wshilong@ddn.com>
> 
> Signed-off-by: Wang Shilong <wshilong@ddn.com>
> ---
>  fs/xfs/xfs_iops.c  | 51 +++++++++++++++++++++++++++++++++++++---------
>  fs/xfs/xfs_linux.h | 10 +++++++++
>  2 files changed, 51 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index f48ffd7a8d3e..c10466fe6ed4 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -589,7 +589,8 @@ xfs_vn_change_ok(
>  	struct dentry	*dentry,
>  	struct iattr	*iattr)
>  {
> -	struct xfs_mount	*mp = XFS_I(d_inode(dentry))->i_mount;
> +	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
> +	struct xfs_mount	*mp = ip->i_mount;
>  
>  	if (mp->m_flags & XFS_MOUNT_RDONLY)
>  		return -EROFS;
> @@ -597,6 +598,13 @@ xfs_vn_change_ok(
>  	if (XFS_FORCED_SHUTDOWN(mp))
>  		return -EIO;
>  
> +	 if ((iattr->ia_valid & ATTR_PROJID) &&
> +	     current_user_ns() != &init_user_ns) {
> +		if (!projid_eq(xfs_projid_to_kprojid(xfs_get_projid(ip)),
> +			       iattr->ia_projid))
> +			return -EPERM;
> +	}

See previous comments about this.

> +
>  	return setattr_prepare(dentry, iattr);
>  }
>  
> @@ -619,8 +627,10 @@ xfs_setattr_nonsize(
>  	int			error;
>  	kuid_t			uid = GLOBAL_ROOT_UID, iuid = GLOBAL_ROOT_UID;
>  	kgid_t			gid = GLOBAL_ROOT_GID, igid = GLOBAL_ROOT_GID;
> -	struct xfs_dquot	*udqp = NULL, *gdqp = NULL;
> +	kprojid_t		projid, iprojid;

So, uninitialised, unlink the uid/gids.

These shoul dbe GLOBAL_ROOT_PROJID, which probably should be:

#define GLOBAL_ROOT_PROJID KPROJIDT_INIT(0)

to match these:

#define XFS_PROJID_DEFAULT   0
#define F2FS_DEF_PROJID         0       /* default project ID */
#define  EXT4_DEF_PROJID         0

> +	struct xfs_dquot	*udqp = NULL, *gdqp = NULL, *pdqp = NULL;
>  	struct xfs_dquot	*olddquot1 = NULL, *olddquot2 = NULL;
> +	struct xfs_dquot	*olddquot3 = NULL;
>  
>  	ASSERT((mask & ATTR_SIZE) == 0);
>  
> @@ -632,7 +642,7 @@ xfs_setattr_nonsize(
>  	 * If the IDs do change before we take the ilock, we're covered
>  	 * because the i_*dquot fields will get updated anyway.
>  	 */
> -	if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID))) {
> +	if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID|ATTR_PROJID))) {
>  		uint	qflags = 0;
>  
>  		if ((mask & ATTR_UID) && XFS_IS_UQUOTA_ON(mp)) {
> @@ -647,18 +657,25 @@ xfs_setattr_nonsize(
>  		}  else {
>  			gid = inode->i_gid;
>  		}
> +		if ((mask & ATTR_PROJID) && XFS_IS_PQUOTA_ON(mp)) {
> +			projid = iattr->ia_projid;
> +			qflags |= XFS_QMOPT_PQUOTA;
> +		}  else {
> +			projid = xfs_projid_to_kprojid(xfs_get_projid(ip));
> +		}

Hmmm. why would we convert the XFS on-disk project ID to a kernel
representation, only to immediately:

>  
>  		/*
> -		 * We take a reference when we initialize udqp and gdqp,
> +		 * We take a reference when we initialize udqp,gdqp and pdqp,
>  		 * so it is important that we never blindly double trip on
>  		 * the same variable. See xfs_create() for an example.
>  		 */
>  		ASSERT(udqp == NULL);
>  		ASSERT(gdqp == NULL);
> +		ASSERT(pdqp == NULL);
>  		error = xfs_qm_vop_dqalloc(ip, xfs_kuid_to_uid(uid),
>  					   xfs_kgid_to_gid(gid),
> -					   xfs_get_projid(ip),
> -					   qflags, &udqp, &gdqp, NULL);
> +					   xfs_kprojid_to_projid(projid),
> +					   qflags, &udqp, &gdqp, &pdqp);

Convert it back to the XFS on disk representation? Perhaps:

		if ((mask & ATTR_PROJID) && XFS_IS_PQUOTA_ON(mp)) {
			projid = xfs_kprojid_to_projid(iattr->ia_projid);
			qflags |= XFS_QMOPT_PQUOTA;
		}  else {
			projid = xfs_get_projid(ip);
		}

Unless, of course, we promote the the project ID into the struct
inode so it matches uid and gid. This code is really telling me that
we should be promoting it before we make thse changes...

> @@ -673,7 +690,7 @@ xfs_setattr_nonsize(
>  	/*
>  	 * Change file ownership.  Must be the owner or privileged.
>  	 */
> -	if (mask & (ATTR_UID|ATTR_GID)) {
> +	if (mask & (ATTR_UID|ATTR_GID|ATTR_PROJID)) {
>  		/*
>  		 * These IDs could have changed since we last looked at them.
>  		 * But, we're assured that if the ownership did change
> @@ -682,8 +699,10 @@ xfs_setattr_nonsize(
>  		 */
>  		iuid = inode->i_uid;
>  		igid = inode->i_gid;
> +		iprojid = xfs_projid_to_kprojid(xfs_get_projid(ip));
>  		gid = (mask & ATTR_GID) ? iattr->ia_gid : igid;
>  		uid = (mask & ATTR_UID) ? iattr->ia_uid : iuid;
> +		projid = (mask & ATTR_PROJID) ? iattr->ia_projid : iprojid;
>  
>  		/*
>  		 * Do a quota reservation only if uid/gid is actually
> @@ -691,10 +710,11 @@ xfs_setattr_nonsize(
>  		 */
>  		if (XFS_IS_QUOTA_RUNNING(mp) &&
>  		    ((XFS_IS_UQUOTA_ON(mp) && !uid_eq(iuid, uid)) ||
> -		     (XFS_IS_GQUOTA_ON(mp) && !gid_eq(igid, gid)))) {
> +		     (XFS_IS_GQUOTA_ON(mp) && !gid_eq(igid, gid)) ||
> +		     (XFS_IS_PQUOTA_ON(mp) && !projid_eq(iprojid, projid)))) {
>  			ASSERT(tp);
>  			error = xfs_qm_vop_chown_reserve(tp, ip, udqp, gdqp,
> -						NULL, capable(CAP_FOWNER) ?
> +						pdqp, capable(CAP_FOWNER) ?
>  						XFS_QMOPT_FORCE_RES : 0);
>  			if (error)	/* out of quota */
>  				goto out_cancel;
> @@ -704,7 +724,7 @@ xfs_setattr_nonsize(
>  	/*
>  	 * Change file ownership.  Must be the owner or privileged.
>  	 */
> -	if (mask & (ATTR_UID|ATTR_GID)) {
> +	if (mask & (ATTR_UID|ATTR_GID|ATTR_PROJID)) {
>  		/*
>  		 * CAP_FSETID overrides the following restrictions:
>  		 *
> @@ -741,6 +761,15 @@ xfs_setattr_nonsize(
>  			ip->i_d.di_gid = xfs_kgid_to_gid(gid);
>  			inode->i_gid = gid;
>  		}
> +		if (!projid_eq(iprojid, projid)) {
> +			if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_PQUOTA_ON(mp)) {
> +				ASSERT(mask & ATTR_PROJID);
> +				ASSERT(pdqp);
> +				olddquot3 = xfs_qm_vop_chown(tp, ip,
> +							&ip->i_pdquot, pdqp);
> +			}
> +			xfs_set_projid(ip, xfs_kprojid_to_projid(projid));
> +		}
>  	}

Ok, this adds another set of boilerplate code here. This is starting
to need some factoring work. Not needed for this patchset, though.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com