Re: [PATCH v2] ceph: fix statfs for subdir mounts

[Luís Henriques]

On Wed, Apr 27, 2022 at 11:07:40AM -0400, Jeff Layton wrote:
> On Wed, 2022-04-27 at 15:33 +0100, Luís Henriques wrote:
> > When doing a mount using as base a directory that has 'max_bytes' quotas
> > statfs uses that value as the total; if a subdirectory is used instead,
> > the same 'max_bytes' too in statfs, unless there is another quota set.
> > 
> > Unfortunately, if this subdirectory only has the 'max_files' quota set,
> > then statfs uses the filesystem total.  Fix this by making sure we only
> > lookup realms that contain the 'max_bytes' quota.
> > 
> > Link: https://tracker.ceph.com/issues/55090
> > Cc: Ryan Taylor <rptaylor@xxxxxxx>
> > Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
> > ---
> > As I mentioned in v1, I do *not* think this really fixes the tracker
> > above, as the bug reporter never mentioned setting quotas in the subdir.
> > 
> > Changes since v1:
> > Moved some more logic into __ceph_has_any_quota() function.
> > 
> >  fs/ceph/inode.c |  2 +-
> >  fs/ceph/quota.c | 19 +++++++++++--------
> >  fs/ceph/super.h | 28 ++++++++++++++++++++++++----
> >  3 files changed, 36 insertions(+), 13 deletions(-)
> > 
> > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> > index 5de7bb9048b7..4b7406d6fbe4 100644
> > --- a/fs/ceph/inode.c
> > +++ b/fs/ceph/inode.c
> > @@ -691,7 +691,7 @@ void ceph_evict_inode(struct inode *inode)
> >  
> >  	__ceph_remove_caps(ci);
> >  
> > -	if (__ceph_has_any_quota(ci))
> > +	if (__ceph_has_any_quota(ci, QUOTA_GET_ANY))
> >  		ceph_adjust_quota_realms_count(inode, false);
> >  
> >  	/*
> > diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
> > index a338a3ec0dc4..e9f7ca18cdb7 100644
> > --- a/fs/ceph/quota.c
> > +++ b/fs/ceph/quota.c
> > @@ -195,9 +195,9 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
> >  
> >  /*
> >   * This function walks through the snaprealm for an inode and returns the
> > - * ceph_snap_realm for the first snaprealm that has quotas set (either max_files
> > - * or max_bytes).  If the root is reached, return the root ceph_snap_realm
> > - * instead.
> > + * ceph_snap_realm for the first snaprealm that has quotas set (max_files,
> > + * max_bytes, or any, depending on the 'which_quota' argument).  If the root is
> > + * reached, return the root ceph_snap_realm instead.
> >   *
> >   * Note that the caller is responsible for calling ceph_put_snap_realm() on the
> >   * returned realm.
> > @@ -209,7 +209,9 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
> >   * will be restarted.
> >   */
> >  static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
> > -					       struct inode *inode, bool retry)
> > +					       struct inode *inode,
> > +					       enum quota_get_realm which_quota,
> > +					       bool retry)
> >  {
> >  	struct ceph_inode_info *ci = NULL;
> >  	struct ceph_snap_realm *realm, *next;
> > @@ -248,7 +250,7 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
> >  		}
> >  
> >  		ci = ceph_inode(in);
> > -		has_quota = __ceph_has_any_quota(ci);
> > +		has_quota = __ceph_has_any_quota(ci, which_quota);
> >  		iput(in);
> >  
> >  		next = realm->parent;
> > @@ -279,8 +281,8 @@ bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
> >  	 * dropped and we can then restart the whole operation.
> >  	 */
> >  	down_read(&mdsc->snap_rwsem);
> > -	old_realm = get_quota_realm(mdsc, old, true);
> > -	new_realm = get_quota_realm(mdsc, new, false);
> > +	old_realm = get_quota_realm(mdsc, old, QUOTA_GET_ANY, true);
> > +	new_realm = get_quota_realm(mdsc, new, QUOTA_GET_ANY, false);
> >  	if (PTR_ERR(new_realm) == -EAGAIN) {
> >  		up_read(&mdsc->snap_rwsem);
> >  		if (old_realm)
> > @@ -483,7 +485,8 @@ bool ceph_quota_update_statfs(struct ceph_fs_client *fsc, struct kstatfs *buf)
> >  	bool is_updated = false;
> >  
> >  	down_read(&mdsc->snap_rwsem);
> > -	realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root), true);
> > +	realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root),
> > +				QUOTA_GET_MAX_BYTES, true);
> >  	up_read(&mdsc->snap_rwsem);
> >  	if (!realm)
> >  		return false;
> > diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> > index a2e1c83ab29a..3cd96720f14a 100644
> > --- a/fs/ceph/super.h
> > +++ b/fs/ceph/super.h
> > @@ -1317,9 +1317,29 @@ extern void ceph_fs_debugfs_init(struct ceph_fs_client *client);
> >  extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
> >  
> >  /* quota.c */
> > -static inline bool __ceph_has_any_quota(struct ceph_inode_info *ci)
> > +
> > +enum quota_get_realm {
> > +	QUOTA_GET_MAX_FILES,
> > +	QUOTA_GET_MAX_BYTES,
> > +	QUOTA_GET_ANY
> > +};
> > +
> > +static inline bool __ceph_has_any_quota(struct ceph_inode_info *ci,
> > +					enum quota_get_realm which)
> >  {
> > -	return ci->i_max_files || ci->i_max_bytes;
> > +	bool has_quota = false;
> > +
> > +	switch (which) {
> > +	case QUOTA_GET_MAX_BYTES:
> > +		has_quota = !!ci->i_max_bytes;
> > +		break;
> > +	case QUOTA_GET_MAX_FILES:
> > +		has_quota = !!ci->i_max_files;
> > +		break;
> > +	default:
> > +		has_quota = !!(ci->i_max_files || ci->i_max_bytes);
> > +	}
> > +	return has_quota;
> >  }
> >  
> >  extern void ceph_adjust_quota_realms_count(struct inode *inode, bool inc);
> > @@ -1328,10 +1348,10 @@ static inline void __ceph_update_quota(struct ceph_inode_info *ci,
> >  				       u64 max_bytes, u64 max_files)
> >  {
> >  	bool had_quota, has_quota;
> > -	had_quota = __ceph_has_any_quota(ci);
> > +	had_quota = __ceph_has_any_quota(ci, QUOTA_GET_ANY);
> >  	ci->i_max_bytes = max_bytes;
> >  	ci->i_max_files = max_files;
> > -	has_quota = __ceph_has_any_quota(ci);
> > +	has_quota = __ceph_has_any_quota(ci, QUOTA_GET_ANY);
> >  
> >  	if (had_quota != has_quota)
> >  		ceph_adjust_quota_realms_count(&ci->vfs_inode, has_quota);
> 
> Code looks fine. I think Xiubo had suggested renaming the funtion to
> __ceph_has_quota(), but other than that this looks good.

Doh!  Yeah, of course.  Let me quickly respin v3 to fix that.  Thanks.

> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>

Cheers,
--
Luís