diff mbox series

[6/6] Add default quota limit mount options

Message ID 20230420080359.2551150-7-cem@kernel.org (mailing list archive)
State New
Headers show
Series shmem: Add user and group quota support for tmpfs | expand

Commit Message

Carlos Maiolino April 20, 2023, 8:03 a.m. UTC
From: Lukas Czerner <lczerner@redhat.com>

Allow system administrator to set default global quota limits at tmpfs
mount time.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 Documentation/filesystems/tmpfs.rst | 34 ++++++++++----
 include/linux/shmem_fs.h            |  8 ++++
 mm/shmem.c                          | 69 +++++++++++++++++++++++++++++
 mm/shmem_quota.c                    |  9 ++++
 4 files changed, 111 insertions(+), 9 deletions(-)

Comments

Jan Kara April 20, 2023, 2:39 p.m. UTC | #1
On Thu 20-04-23 10:03:59, cem@kernel.org wrote:
> From: Lukas Czerner <lczerner@redhat.com>
> 
> Allow system administrator to set default global quota limits at tmpfs
> mount time.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> ---
>  Documentation/filesystems/tmpfs.rst | 34 ++++++++++----
>  include/linux/shmem_fs.h            |  8 ++++
>  mm/shmem.c                          | 69 +++++++++++++++++++++++++++++
>  mm/shmem_quota.c                    |  9 ++++
>  4 files changed, 111 insertions(+), 9 deletions(-)
> 
> diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
> index 1d4ef4f7cca7e..241c11f86cd73 100644
> --- a/Documentation/filesystems/tmpfs.rst
> +++ b/Documentation/filesystems/tmpfs.rst
> @@ -88,15 +88,31 @@ that instance in a system with many CPUs making intensive use of it.
>  
>  tmpfs also supports quota with the following mount options
>  
> -========  =============================================================
> -quota     User and group quota accounting and enforcement is enabled on
> -          the mount. Tmpfs is using hidden system quota files that are
> -          initialized on mount.
> -usrquota  User quota accounting and enforcement is enabled on the
> -          mount.
> -grpquota  Group quota accounting and enforcement is enabled on the
> -          mount.
> -========  =============================================================
> +======================== =================================================
> +quota                    User and group quota accounting and enforcement
> +                         is enabled on the mount. Tmpfs is using hidden
> +                         system quota files that are initialized on mount.
> +usrquota                 User quota accounting and enforcement is enabled
> +                         on the mount.
> +grpquota                 Group quota accounting and enforcement is enabled
> +                         on the mount.
> +usrquota_block_hardlimit Set global user quota block hard limit.
> +usrquota_inode_hardlimit Set global user quota inode hard limit.
> +grpquota_block_hardlimit Set global group quota block hard limit.
> +grpquota_inode_hardlimit Set global group quota inode hard limit.
> +======================== =================================================
> +
> +None of the quota related mount options can be set or changed on remount.
> +
> +Quota limit parameters accept a suffix k, m or g for kilo, mega and giga
> +and can't be changed on remount. Default global quota limits are taking
> +effect for any and all user/group/project except root the first time the
> +quota entry for user/group/project id is being accessed - typically the
> +first time an inode with a particular id ownership is being created after
> +the mount. In other words, instead of the limits being initialized to zero,
> +they are initialized with the particular value provided with these mount
> +options. The limits can be changed for any user/group id at any time as it
									   ^^ they
> +normally can.
	    ^^^ can be
           
> @@ -3714,6 +3723,50 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
>  		ctx->seen |= SHMEM_SEEN_QUOTA;
>  		ctx->quota_types |= QTYPE_MASK_GRP;
>  		break;
> +	case Opt_usrquota_block_hardlimit:
> +		size = memparse(param->string, &rest);
> +		if (*rest || !size)
> +			goto bad_value;
> +		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
> +			return invalfc(fc,
> +				       "User quota block hardlimit too large.");
> +		ctx->qlimits.usrquota_bhardlimit = size;
> +		ctx->seen |= SHMEM_SEEN_QUOTA;
> +		ctx->quota_types |= QTYPE_MASK_USR;

So if I get it right, the intention here is that if
usrquota_block_hardlimit=value option is used, it automatically enables
user quota accounting and enforcement. I guess it is logical but it is not
documented and I'd prefer to require explicit usrquota mount option to
enable accounting & enforcement - it is then e.g. easier to parse mount
options (in userspace) for finding out whether enforcement is enabled or
not. Also I can imagine we would allow changing the default limits on
remount but it isn't easy to enable quota accounting on remount etc.

> diff --git a/mm/shmem_quota.c b/mm/shmem_quota.c
> index c0b531e2ef688..3cc53f2c35e2c 100644
> --- a/mm/shmem_quota.c
> +++ b/mm/shmem_quota.c
> @@ -166,6 +166,7 @@ static int shmem_acquire_dquot(struct dquot *dquot)
>  {
>  	struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
>  	struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
> +	struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
>  	struct rb_node *parent = NULL, *new_node = NULL;
>  	struct quota_id *new_entry, *entry;
>  	qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
> @@ -195,6 +196,14 @@ static int shmem_acquire_dquot(struct dquot *dquot)
>  	}
>  
>  	new_entry->id = id;
> +	if (dquot->dq_id.type == USRQUOTA) {
> +		new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
> +		new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
> +	} else if (dquot->dq_id.type == GRPQUOTA) {
> +		new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
> +		new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
> +	}
> +
>  	new_node = &new_entry->node;
>  	rb_link_node(new_node, parent, n);
>  	rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);

Maybe in shmem_dquot_release() when usage is 0 and limits are at default
limits, we can free the structure?

								Honza
Carlos Maiolino April 21, 2023, 10:20 a.m. UTC | #2
On Thu, Apr 20, 2023 at 04:39:54PM +0200, Jan Kara wrote:
> On Thu 20-04-23 10:03:59, cem@kernel.org wrote:
> > From: Lukas Czerner <lczerner@redhat.com>
> >
> > Allow system administrator to set default global quota limits at tmpfs
> > mount time.
> >
> > Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > ---
> >  Documentation/filesystems/tmpfs.rst | 34 ++++++++++----
> >  include/linux/shmem_fs.h            |  8 ++++
> >  mm/shmem.c                          | 69 +++++++++++++++++++++++++++++
> >  mm/shmem_quota.c                    |  9 ++++
> >  4 files changed, 111 insertions(+), 9 deletions(-)
> >
> > diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
> > index 1d4ef4f7cca7e..241c11f86cd73 100644
> > --- a/Documentation/filesystems/tmpfs.rst
> > +++ b/Documentation/filesystems/tmpfs.rst
> > @@ -88,15 +88,31 @@ that instance in a system with many CPUs making intensive use of it.
> >
> >  tmpfs also supports quota with the following mount options
> >
> > -========  =============================================================
> > -quota     User and group quota accounting and enforcement is enabled on
> > -          the mount. Tmpfs is using hidden system quota files that are
> > -          initialized on mount.
> > -usrquota  User quota accounting and enforcement is enabled on the
> > -          mount.
> > -grpquota  Group quota accounting and enforcement is enabled on the
> > -          mount.
> > -========  =============================================================
> > +======================== =================================================
> > +quota                    User and group quota accounting and enforcement
> > +                         is enabled on the mount. Tmpfs is using hidden
> > +                         system quota files that are initialized on mount.
> > +usrquota                 User quota accounting and enforcement is enabled
> > +                         on the mount.
> > +grpquota                 Group quota accounting and enforcement is enabled
> > +                         on the mount.
> > +usrquota_block_hardlimit Set global user quota block hard limit.
> > +usrquota_inode_hardlimit Set global user quota inode hard limit.
> > +grpquota_block_hardlimit Set global group quota block hard limit.
> > +grpquota_inode_hardlimit Set global group quota inode hard limit.
> > +======================== =================================================
> > +
> > +None of the quota related mount options can be set or changed on remount.
> > +
> > +Quota limit parameters accept a suffix k, m or g for kilo, mega and giga
> > +and can't be changed on remount. Default global quota limits are taking
> > +effect for any and all user/group/project except root the first time the
> > +quota entry for user/group/project id is being accessed - typically the
> > +first time an inode with a particular id ownership is being created after
> > +the mount. In other words, instead of the limits being initialized to zero,
> > +they are initialized with the particular value provided with these mount
> > +options. The limits can be changed for any user/group id at any time as it
> 									   ^^ they
> > +normally can.
> 	    ^^^ can be
> 
Thanks!

> > @@ -3714,6 +3723,50 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> >  		ctx->seen |= SHMEM_SEEN_QUOTA;
> >  		ctx->quota_types |= QTYPE_MASK_GRP;
> >  		break;
> > +	case Opt_usrquota_block_hardlimit:
> > +		size = memparse(param->string, &rest);
> > +		if (*rest || !size)
> > +			goto bad_value;
> > +		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
> > +			return invalfc(fc,
> > +				       "User quota block hardlimit too large.");
> > +		ctx->qlimits.usrquota_bhardlimit = size;
> > +		ctx->seen |= SHMEM_SEEN_QUOTA;
> > +		ctx->quota_types |= QTYPE_MASK_USR;
> 
> So if I get it right, the intention here is that if
> usrquota_block_hardlimit=value option is used, it automatically enables
> user quota accounting and enforcement. I guess it is logical but it is not
> documented and I'd prefer to require explicit usrquota mount option to
> enable accounting & enforcement - it is then e.g. easier to parse mount
> options (in userspace) for finding out whether enforcement is enabled or
> not.

Hmmm, I think I see what you mean. I can make usrquota_block_hardlimit options
to not actually set the quota flag on quota_types, so this should be explicitly
set by usrquota/grpquota options. Does that work for you?

> Also I can imagine we would allow changing the default limits on
> remount but it isn't easy to enable quota accounting on remount etc.
> 

hmm, yes, maybe enabling default limits to be changed on remount isn't a big
deal, once the quota is already enabled, so everything is already in place.

> > diff --git a/mm/shmem_quota.c b/mm/shmem_quota.c
> > index c0b531e2ef688..3cc53f2c35e2c 100644
> > --- a/mm/shmem_quota.c
> > +++ b/mm/shmem_quota.c
> > @@ -166,6 +166,7 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> >  {
> >  	struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
> >  	struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
> > +	struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
> >  	struct rb_node *parent = NULL, *new_node = NULL;
> >  	struct quota_id *new_entry, *entry;
> >  	qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
> > @@ -195,6 +196,14 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> >  	}
> >
> >  	new_entry->id = id;
> > +	if (dquot->dq_id.type == USRQUOTA) {
> > +		new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
> > +		new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
> > +	} else if (dquot->dq_id.type == GRPQUOTA) {
> > +		new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
> > +		new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
> > +	}
> > +
> >  	new_node = &new_entry->node;
> >  	rb_link_node(new_node, parent, n);
> >  	rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);
> 
> Maybe in shmem_dquot_release() when usage is 0 and limits are at default
> limits, we can free the structure?

hmmm, which struct are you talking about? quota_id? As we do for DQ_FAKE?


> 
> 								Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
Jan Kara April 21, 2023, 10:47 a.m. UTC | #3
On Fri 21-04-23 12:20:42, Carlos Maiolino wrote:
> On Thu, Apr 20, 2023 at 04:39:54PM +0200, Jan Kara wrote:
> > On Thu 20-04-23 10:03:59, cem@kernel.org wrote:
> > > @@ -3714,6 +3723,50 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> > >  		ctx->seen |= SHMEM_SEEN_QUOTA;
> > >  		ctx->quota_types |= QTYPE_MASK_GRP;
> > >  		break;
> > > +	case Opt_usrquota_block_hardlimit:
> > > +		size = memparse(param->string, &rest);
> > > +		if (*rest || !size)
> > > +			goto bad_value;
> > > +		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
> > > +			return invalfc(fc,
> > > +				       "User quota block hardlimit too large.");
> > > +		ctx->qlimits.usrquota_bhardlimit = size;
> > > +		ctx->seen |= SHMEM_SEEN_QUOTA;
> > > +		ctx->quota_types |= QTYPE_MASK_USR;
> > 
> > So if I get it right, the intention here is that if
> > usrquota_block_hardlimit=value option is used, it automatically enables
> > user quota accounting and enforcement. I guess it is logical but it is not
> > documented and I'd prefer to require explicit usrquota mount option to
> > enable accounting & enforcement - it is then e.g. easier to parse mount
> > options (in userspace) for finding out whether enforcement is enabled or
> > not.
> 
> Hmmm, I think I see what you mean. I can make usrquota_block_hardlimit options
> to not actually set the quota flag on quota_types, so this should be explicitly
> set by usrquota/grpquota options. Does that work for you?

Yes, works for me!

> > Also I can imagine we would allow changing the default limits on
> > remount but it isn't easy to enable quota accounting on remount etc.
> > 
> 
> hmm, yes, maybe enabling default limits to be changed on remount isn't a big
> deal, once the quota is already enabled, so everything is already in place.

Exactly. I don't say you have to do it now as I don't think that is super
useful. But if there's a demand we can easily do it.

> > > diff --git a/mm/shmem_quota.c b/mm/shmem_quota.c
> > > index c0b531e2ef688..3cc53f2c35e2c 100644
> > > --- a/mm/shmem_quota.c
> > > +++ b/mm/shmem_quota.c
> > > @@ -166,6 +166,7 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> > >  {
> > >  	struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
> > >  	struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
> > > +	struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
> > >  	struct rb_node *parent = NULL, *new_node = NULL;
> > >  	struct quota_id *new_entry, *entry;
> > >  	qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
> > > @@ -195,6 +196,14 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> > >  	}
> > >
> > >  	new_entry->id = id;
> > > +	if (dquot->dq_id.type == USRQUOTA) {
> > > +		new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
> > > +		new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
> > > +	} else if (dquot->dq_id.type == GRPQUOTA) {
> > > +		new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
> > > +		new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
> > > +	}
> > > +
> > >  	new_node = &new_entry->node;
> > >  	rb_link_node(new_node, parent, n);
> > >  	rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);
> > 
> > Maybe in shmem_dquot_release() when usage is 0 and limits are at default
> > limits, we can free the structure?
> 
> hmmm, which struct are you talking about? quota_id? As we do for DQ_FAKE?

Yes.

								Honza
Carlos Maiolino April 21, 2023, 12:34 p.m. UTC | #4
On Fri, Apr 21, 2023 at 12:47:43PM +0200, Jan Kara wrote:
> On Fri 21-04-23 12:20:42, Carlos Maiolino wrote:
> > On Thu, Apr 20, 2023 at 04:39:54PM +0200, Jan Kara wrote:
> > > On Thu 20-04-23 10:03:59, cem@kernel.org wrote:
> > > > @@ -3714,6 +3723,50 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> > > >  		ctx->seen |= SHMEM_SEEN_QUOTA;
> > > >  		ctx->quota_types |= QTYPE_MASK_GRP;
> > > >  		break;
> > > > +	case Opt_usrquota_block_hardlimit:
> > > > +		size = memparse(param->string, &rest);
> > > > +		if (*rest || !size)
> > > > +			goto bad_value;
> > > > +		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
> > > > +			return invalfc(fc,
> > > > +				       "User quota block hardlimit too large.");
> > > > +		ctx->qlimits.usrquota_bhardlimit = size;
> > > > +		ctx->seen |= SHMEM_SEEN_QUOTA;
> > > > +		ctx->quota_types |= QTYPE_MASK_USR;
> > >
> > > So if I get it right, the intention here is that if
> > > usrquota_block_hardlimit=value option is used, it automatically enables
> > > user quota accounting and enforcement. I guess it is logical but it is not
> > > documented and I'd prefer to require explicit usrquota mount option to
> > > enable accounting & enforcement - it is then e.g. easier to parse mount
> > > options (in userspace) for finding out whether enforcement is enabled or
> > > not.
> >
> > Hmmm, I think I see what you mean. I can make usrquota_block_hardlimit options
> > to not actually set the quota flag on quota_types, so this should be explicitly
> > set by usrquota/grpquota options. Does that work for you?
> 
> Yes, works for me!

Great!
> 
> > > Also I can imagine we would allow changing the default limits on
> > > remount but it isn't easy to enable quota accounting on remount etc.
> > >
> >
> > hmm, yes, maybe enabling default limits to be changed on remount isn't a big
> > deal, once the quota is already enabled, so everything is already in place.
> 
> Exactly. I don't say you have to do it now as I don't think that is super
> useful. But if there's a demand we can easily do it.

Sounds good :) If you don't mind, I'd postpone it, as I am planning to add
prjquotas to it later, I can add it to the same series, just to avoid adding
more review overhead to this one.


> 
> > > > diff --git a/mm/shmem_quota.c b/mm/shmem_quota.c
> > > > index c0b531e2ef688..3cc53f2c35e2c 100644
> > > > --- a/mm/shmem_quota.c
> > > > +++ b/mm/shmem_quota.c
> > > > @@ -166,6 +166,7 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> > > >  {
> > > >  	struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
> > > >  	struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
> > > > +	struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
> > > >  	struct rb_node *parent = NULL, *new_node = NULL;
> > > >  	struct quota_id *new_entry, *entry;
> > > >  	qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
> > > > @@ -195,6 +196,14 @@ static int shmem_acquire_dquot(struct dquot *dquot)
> > > >  	}
> > > >
> > > >  	new_entry->id = id;
> > > > +	if (dquot->dq_id.type == USRQUOTA) {
> > > > +		new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
> > > > +		new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
> > > > +	} else if (dquot->dq_id.type == GRPQUOTA) {
> > > > +		new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
> > > > +		new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
> > > > +	}
> > > > +
> > > >  	new_node = &new_entry->node;
> > > >  	rb_link_node(new_node, parent, n);
> > > >  	rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);
> > >
> > > Maybe in shmem_dquot_release() when usage is 0 and limits are at default
> > > limits, we can free the structure?
> >
> > hmmm, which struct are you talking about? quota_id? As we do for DQ_FAKE?
> 
> Yes.
> 
> 								Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
diff mbox series

Patch

diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index 1d4ef4f7cca7e..241c11f86cd73 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -88,15 +88,31 @@  that instance in a system with many CPUs making intensive use of it.
 
 tmpfs also supports quota with the following mount options
 
-========  =============================================================
-quota     User and group quota accounting and enforcement is enabled on
-          the mount. Tmpfs is using hidden system quota files that are
-          initialized on mount.
-usrquota  User quota accounting and enforcement is enabled on the
-          mount.
-grpquota  Group quota accounting and enforcement is enabled on the
-          mount.
-========  =============================================================
+======================== =================================================
+quota                    User and group quota accounting and enforcement
+                         is enabled on the mount. Tmpfs is using hidden
+                         system quota files that are initialized on mount.
+usrquota                 User quota accounting and enforcement is enabled
+                         on the mount.
+grpquota                 Group quota accounting and enforcement is enabled
+                         on the mount.
+usrquota_block_hardlimit Set global user quota block hard limit.
+usrquota_inode_hardlimit Set global user quota inode hard limit.
+grpquota_block_hardlimit Set global group quota block hard limit.
+grpquota_inode_hardlimit Set global group quota inode hard limit.
+======================== =================================================
+
+None of the quota related mount options can be set or changed on remount.
+
+Quota limit parameters accept a suffix k, m or g for kilo, mega and giga
+and can't be changed on remount. Default global quota limits are taking
+effect for any and all user/group/project except root the first time the
+quota entry for user/group/project id is being accessed - typically the
+first time an inode with a particular id ownership is being created after
+the mount. In other words, instead of the limits being initialized to zero,
+they are initialized with the particular value provided with these mount
+options. The limits can be changed for any user/group id at any time as it
+normally can.
 
 Note that tmpfs quotas do not support user namespaces so no uid/gid
 translation is done if quotas are enable inside user namespaces.
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index b8e421e349868..8ca5e969f00fc 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -41,6 +41,13 @@  struct shmem_inode_info {
 	(FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
 #define SHMEM_FL_INHERITED		(FS_NODUMP_FL | FS_NOATIME_FL)
 
+struct shmem_quota_limits {
+	qsize_t usrquota_bhardlimit; /* Default user quota block hard limit */
+	qsize_t usrquota_ihardlimit; /* Default user quota inode hard limit */
+	qsize_t grpquota_bhardlimit; /* Default group quota block hard limit */
+	qsize_t grpquota_ihardlimit; /* Default group quota inode hard limit */
+};
+
 struct shmem_sb_info {
 	unsigned long max_blocks;   /* How many blocks are allowed */
 	struct percpu_counter used_blocks;  /* How many are allocated */
@@ -58,6 +65,7 @@  struct shmem_sb_info {
 	spinlock_t shrinklist_lock;   /* Protects shrinklist */
 	struct list_head shrinklist;  /* List of shinkable inodes */
 	unsigned long shrinklist_len; /* Length of shrinklist */
+	struct shmem_quota_limits qlimits; /* Default quota limits */
 };
 
 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
diff --git a/mm/shmem.c b/mm/shmem.c
index dd9faf2c5c875..2832ace81515f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -118,6 +118,7 @@  struct shmem_options {
 	int huge;
 	int seen;
 	unsigned short quota_types;
+	struct shmem_quota_limits qlimits;
 #define SHMEM_SEEN_BLOCKS 1
 #define SHMEM_SEEN_INODES 2
 #define SHMEM_SEEN_HUGE 4
@@ -3593,6 +3594,10 @@  enum shmem_param {
 	Opt_quota,
 	Opt_usrquota,
 	Opt_grpquota,
+	Opt_usrquota_block_hardlimit,
+	Opt_usrquota_inode_hardlimit,
+	Opt_grpquota_block_hardlimit,
+	Opt_grpquota_inode_hardlimit,
 };
 
 static const struct constant_table shmem_param_enums_huge[] = {
@@ -3618,6 +3623,10 @@  const struct fs_parameter_spec shmem_fs_parameters[] = {
 	fsparam_flag  ("quota",		Opt_quota),
 	fsparam_flag  ("usrquota",	Opt_usrquota),
 	fsparam_flag  ("grpquota",	Opt_grpquota),
+	fsparam_string("usrquota_block_hardlimit", Opt_usrquota_block_hardlimit),
+	fsparam_string("usrquota_inode_hardlimit", Opt_usrquota_inode_hardlimit),
+	fsparam_string("grpquota_block_hardlimit", Opt_grpquota_block_hardlimit),
+	fsparam_string("grpquota_inode_hardlimit", Opt_grpquota_inode_hardlimit),
 #endif
 	{}
 };
@@ -3714,6 +3723,50 @@  static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 		ctx->seen |= SHMEM_SEEN_QUOTA;
 		ctx->quota_types |= QTYPE_MASK_GRP;
 		break;
+	case Opt_usrquota_block_hardlimit:
+		size = memparse(param->string, &rest);
+		if (*rest || !size)
+			goto bad_value;
+		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
+			return invalfc(fc,
+				       "User quota block hardlimit too large.");
+		ctx->qlimits.usrquota_bhardlimit = size;
+		ctx->seen |= SHMEM_SEEN_QUOTA;
+		ctx->quota_types |= QTYPE_MASK_USR;
+		break;
+	case Opt_grpquota_block_hardlimit:
+		size = memparse(param->string, &rest);
+		if (*rest || !size)
+			goto bad_value;
+		if (size > SHMEM_QUOTA_MAX_SPC_LIMIT)
+			return invalfc(fc,
+				       "Group quota block hardlimit too large.");
+		ctx->qlimits.grpquota_bhardlimit = size;
+		ctx->seen |= SHMEM_SEEN_QUOTA;
+		ctx->quota_types |= QTYPE_MASK_GRP;
+		break;
+	case Opt_usrquota_inode_hardlimit:
+		size = memparse(param->string, &rest);
+		if (*rest || !size)
+			goto bad_value;
+		if (size > SHMEM_QUOTA_MAX_INO_LIMIT)
+			return invalfc(fc,
+				       "User quota inode hardlimit too large.");
+		ctx->qlimits.usrquota_ihardlimit = size;
+		ctx->seen |= SHMEM_SEEN_QUOTA;
+		ctx->quota_types |= QTYPE_MASK_USR;
+		break;
+	case Opt_grpquota_inode_hardlimit:
+		size = memparse(param->string, &rest);
+		if (*rest || !size)
+			goto bad_value;
+		if (size > SHMEM_QUOTA_MAX_INO_LIMIT)
+			return invalfc(fc,
+				       "Group quota inode hardlimit too large.");
+		ctx->qlimits.grpquota_ihardlimit = size;
+		ctx->seen |= SHMEM_SEEN_QUOTA;
+		ctx->quota_types |= QTYPE_MASK_GRP;
+		break;
 	}
 	return 0;
 
@@ -3819,6 +3872,18 @@  static int shmem_reconfigure(struct fs_context *fc)
 		goto out;
 	}
 
+#ifdef CONFIG_TMPFS_QUOTA
+#define CHANGED_LIMIT(name)						\
+	(ctx->qlimits.name## hardlimit &&				\
+	(ctx->qlimits.name## hardlimit != sbinfo->qlimits.name## hardlimit))
+
+	if (CHANGED_LIMIT(usrquota_b) || CHANGED_LIMIT(usrquota_i) ||
+	    CHANGED_LIMIT(grpquota_b) || CHANGED_LIMIT(grpquota_i)) {
+		err = "Cannot change global quota limit on remount";
+		goto out;
+	}
+#endif /* CONFIG_TMPFS_QUOTA */
+
 	if (ctx->seen & SHMEM_SEEN_HUGE)
 		sbinfo->huge = ctx->huge;
 	if (ctx->seen & SHMEM_SEEN_INUMS)
@@ -3988,6 +4053,10 @@  static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 		sb->s_qcop = &dquot_quotactl_sysfile_ops;
 		sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
 
+		/* Copy the default limits from ctx into sbinfo */
+		memcpy(&sbinfo->qlimits, &ctx->qlimits,
+		       sizeof(struct shmem_quota_limits));
+
 		if (shmem_enable_quotas(sb, ctx->quota_types))
 			goto failed;
 	}
diff --git a/mm/shmem_quota.c b/mm/shmem_quota.c
index c0b531e2ef688..3cc53f2c35e2c 100644
--- a/mm/shmem_quota.c
+++ b/mm/shmem_quota.c
@@ -166,6 +166,7 @@  static int shmem_acquire_dquot(struct dquot *dquot)
 {
 	struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
 	struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
+	struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
 	struct rb_node *parent = NULL, *new_node = NULL;
 	struct quota_id *new_entry, *entry;
 	qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
@@ -195,6 +196,14 @@  static int shmem_acquire_dquot(struct dquot *dquot)
 	}
 
 	new_entry->id = id;
+	if (dquot->dq_id.type == USRQUOTA) {
+		new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
+		new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
+	} else if (dquot->dq_id.type == GRPQUOTA) {
+		new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
+		new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
+	}
+
 	new_node = &new_entry->node;
 	rb_link_node(new_node, parent, n);
 	rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);