ceph: quota: add initial infrastructure to support cephfs quotas

This patch adds the infrastructure required to support cephfs quotas as it
is currently implemented in the ceph fuse client.  Cephfs quotas can be
set on any directory, and can restrict the number of bytes or the number
of files stored beneath that point in the directory hierarchy.

Quotas are set using the extended attributes 'ceph.quota.max_files' and
'ceph.quota.max_bytes', and can be removed by setting these attributes to
'0'.

Link: http://tracker.ceph.com/issues/22372
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Documentation/filesystems/ceph.txt

@@ -62,6 +62,18 @@ subdirectories, and a summation of all nested file sizes.  This makes
 the identification of large disk space consumers relatively quick, as
 no 'du' or similar recursive scan of the file system is required.
 
+Finally, Ceph also allows quotas to be set on any directory in the system.
+The quota can restrict the number of bytes or the number of files stored
+beneath that point in the directory hierarchy.  Quotas can be set using
+extended attributes 'ceph.quota.max_files' and 'ceph.quota.max_bytes', eg:
+
+ setfattr -n ceph.quota.max_bytes -v 100000000 /some/dir
+ getfattr -n ceph.quota.max_bytes /some/dir
+
+A limitation of the current quotas implementation is that it relies on the
+cooperation of the client mounting the file system to stop writers when a
+limit is reached.  A modified or adversarial client cannot be prevented
+from writing as much data as it needs.
 
 Mount Syntax
 ============

fs/ceph/Makefile

@@ -6,7 +6,7 @@
 obj-$(CONFIG_CEPH_FS) += ceph.o
 
 ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
-	export.o caps.o snap.o xattr.o \
+	export.o caps.o snap.o xattr.o quota.o \
 	mds_client.o mdsmap.o strings.o ceph_frag.o \
 	debugfs.o
 

fs/ceph/inode.c

@@ -441,6 +441,9 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
 	atomic64_set(&ci->i_complete_seq[1], 0);
 	ci->i_symlink = NULL;
 
+	ci->i_max_bytes = 0;
+	ci->i_max_files = 0;
+
 	memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
 	RCU_INIT_POINTER(ci->i_layout.pool_ns, NULL);
 
@@ -790,6 +793,9 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
 	inode->i_rdev = le32_to_cpu(info->rdev);
 	inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
 
+	ci->i_max_bytes = iinfo->max_bytes;
+	ci->i_max_files = iinfo->max_files;
+
 	if ((new_version || (new_issued & CEPH_CAP_AUTH_SHARED)) &&
 	    (issued & CEPH_CAP_AUTH_EXCL) == 0) {
 		inode->i_mode = le32_to_cpu(info->mode);

fs/ceph/mds_client.c

@@ -100,6 +100,26 @@ static int parse_reply_info_in(void **p, void *end,
 	} else
 		info->inline_version = CEPH_INLINE_NONE;
 
+	if (features & CEPH_FEATURE_MDS_QUOTA) {
+		u8 struct_v, struct_compat;
+		u32 struct_len;
+
+		/*
+		 * both struct_v and struct_compat are expected to be >= 1
+		 */
+		ceph_decode_8_safe(p, end, struct_v, bad);
+		ceph_decode_8_safe(p, end, struct_compat, bad);
+		if (!struct_v || !struct_compat)
+			goto bad;
+		ceph_decode_32_safe(p, end, struct_len, bad);
+		ceph_decode_need(p, end, struct_len, bad);
+		ceph_decode_64_safe(p, end, info->max_bytes, bad);
+		ceph_decode_64_safe(p, end, info->max_files, bad);
+	} else {
+		info->max_bytes = 0;
+		info->max_files = 0;
+	}
+
 	info->pool_ns_len = 0;
 	info->pool_ns_data = NULL;
 	if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
@@ -4082,6 +4102,9 @@ static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
 	case CEPH_MSG_CLIENT_LEASE:
 		handle_lease(mdsc, s, msg);
 		break;
+	case CEPH_MSG_CLIENT_QUOTA:
+		ceph_handle_quota(mdsc, s, msg);
+		break;
 
 	default:
 		pr_err("received unknown message type %d %s\n", type,

fs/ceph/mds_client.h

@@ -49,6 +49,8 @@ struct ceph_mds_reply_info_in {
 	char *inline_data;
 	u32 pool_ns_len;
 	char *pool_ns_data;
+	u64 max_bytes;
+	u64 max_files;
 };
 
 struct ceph_mds_reply_dir_entry {

fs/ceph/quota.c

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * quota.c - CephFS quota
+ *
+ * Copyright (C) 2017-2018 SUSE
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "super.h"
+#include "mds_client.h"
+
+void ceph_handle_quota(struct ceph_mds_client *mdsc,
+		       struct ceph_mds_session *session,
+		       struct ceph_msg *msg)
+{
+	struct super_block *sb = mdsc->fsc->sb;
+	struct ceph_mds_quota *h = msg->front.iov_base;
+	struct ceph_vino vino;
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+
+	if (msg->front.iov_len != sizeof(*h)) {
+		pr_err("%s corrupt message mds%d len %d\n", __func__,
+		       session->s_mds, (int)msg->front.iov_len);
+		ceph_msg_dump(msg);
+		return;
+	}
+
+	/* increment msg sequence number */
+	mutex_lock(&session->s_mutex);
+	session->s_seq++;
+	mutex_unlock(&session->s_mutex);
+
+	/* lookup inode */
+	vino.ino = le64_to_cpu(h->ino);
+	vino.snap = CEPH_NOSNAP;
+	inode = ceph_find_inode(sb, vino);
+	if (!inode) {
+		pr_warn("Failed to find inode %llu\n", vino.ino);
+		return;
+	}
+	ci = ceph_inode(inode);
+
+	spin_lock(&ci->i_ceph_lock);
+	ci->i_rbytes = le64_to_cpu(h->rbytes);
+	ci->i_rfiles = le64_to_cpu(h->rfiles);
+	ci->i_rsubdirs = le64_to_cpu(h->rsubdirs);
+	ci->i_max_bytes = le64_to_cpu(h->max_bytes);
+	ci->i_max_files = le64_to_cpu(h->max_files);
+	spin_unlock(&ci->i_ceph_lock);
+
+	iput(inode);
+}

fs/ceph/super.h

@@ -310,6 +310,9 @@ struct ceph_inode_info {
 	u64 i_rbytes, i_rfiles, i_rsubdirs;
 	u64 i_files, i_subdirs;
 
+	/* quotas */
+	u64 i_max_bytes, i_max_files;
+
 	struct rb_root i_fragtree;
 	int i_fragtree_nsplits;
 	struct mutex i_fragtree_mutex;
@@ -1070,4 +1073,9 @@ extern int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
 extern int ceph_fs_debugfs_init(struct ceph_fs_client *client);
 extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
 
+/* quota.c */
+extern void ceph_handle_quota(struct ceph_mds_client *mdsc,
+			      struct ceph_mds_session *session,
+			      struct ceph_msg *msg);
+
 #endif /* _FS_CEPH_SUPER_H */

fs/ceph/xattr.c

@@ -224,6 +224,31 @@ static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
 			(long)ci->i_rctime.tv_nsec);
 }
 
+/* quotas */
+
+static bool ceph_vxattrcb_quota_exists(struct ceph_inode_info *ci)
+{
+	return (ci->i_max_files || ci->i_max_bytes);
+}
+
+static size_t ceph_vxattrcb_quota(struct ceph_inode_info *ci, char *val,
+				  size_t size)
+{
+	return snprintf(val, size, "max_bytes=%llu max_files=%llu",
+			ci->i_max_bytes, ci->i_max_files);
+}
+
+static size_t ceph_vxattrcb_quota_max_bytes(struct ceph_inode_info *ci,
+					    char *val, size_t size)
+{
+	return snprintf(val, size, "%llu", ci->i_max_bytes);
+}
+
+static size_t ceph_vxattrcb_quota_max_files(struct ceph_inode_info *ci,
+					    char *val, size_t size)
+{
+	return snprintf(val, size, "%llu", ci->i_max_files);
+}
 
 #define CEPH_XATTR_NAME(_type, _name)	XATTR_CEPH_PREFIX #_type "." #_name
 #define CEPH_XATTR_NAME2(_type, _name, _name2)	\
@@ -247,6 +272,15 @@ static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
 		.hidden = true,			\
 		.exists_cb = ceph_vxattrcb_layout_exists,	\
 	}
+#define XATTR_QUOTA_FIELD(_type, _name)					\
+	{								\
+		.name = CEPH_XATTR_NAME(_type, _name),			\
+		.name_size = sizeof(CEPH_XATTR_NAME(_type, _name)),	\
+		.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name,	\
+		.readonly = false,					\
+		.hidden = true,						\
+		.exists_cb = ceph_vxattrcb_quota_exists,		\
+	}
 
 static struct ceph_vxattr ceph_dir_vxattrs[] = {
 	{
@@ -270,6 +304,16 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
 	XATTR_NAME_CEPH(dir, rsubdirs),
 	XATTR_NAME_CEPH(dir, rbytes),
 	XATTR_NAME_CEPH(dir, rctime),
+	{
+		.name = "ceph.quota",
+		.name_size = sizeof("ceph.quota"),
+		.getxattr_cb = ceph_vxattrcb_quota,
+		.readonly = false,
+		.hidden = true,
+		.exists_cb = ceph_vxattrcb_quota_exists,
+	},
+	XATTR_QUOTA_FIELD(quota, max_bytes),
+	XATTR_QUOTA_FIELD(quota, max_files),
 	{ .name = NULL, 0 }	/* Required table terminator */
 };
 static size_t ceph_dir_vxattrs_name_size;	/* total size of all names */

include/linux/ceph/ceph_features.h

@@ -204,6 +204,7 @@ DEFINE_CEPH_FEATURE_DEPRECATED(63, 1, RESERVED_BROKEN, LUMINOUS) // client-facin
 	 CEPH_FEATURE_OSD_PRIMARY_AFFINITY |	\
 	 CEPH_FEATURE_MSGR_KEEPALIVE2 |		\
 	 CEPH_FEATURE_OSD_POOLRESEND |		\
+	 CEPH_FEATURE_MDS_QUOTA |		\
 	 CEPH_FEATURE_CRUSH_V4 |		\
 	 CEPH_FEATURE_NEW_OSDOP_ENCODING |	\
 	 CEPH_FEATURE_SERVER_JEWEL |		\

include/linux/ceph/ceph_fs.h

@@ -134,6 +134,7 @@ struct ceph_dir_layout {
 #define CEPH_MSG_CLIENT_LEASE           0x311
 #define CEPH_MSG_CLIENT_SNAP            0x312
 #define CEPH_MSG_CLIENT_CAPRELEASE      0x313
+#define CEPH_MSG_CLIENT_QUOTA           0x314
 
 /* pool ops */
 #define CEPH_MSG_POOLOP_REPLY           48
@@ -807,4 +808,20 @@ struct ceph_mds_snap_realm {
 } __attribute__ ((packed));
 /* followed by my snap list, then prior parent snap list */
 
+/*
+ * quotas
+ */
+struct ceph_mds_quota {
+	__le64 ino;		/* ino */
+	struct ceph_timespec rctime;
+	__le64 rbytes;		/* dir stats */
+	__le64 rfiles;
+	__le64 rsubdirs;
+	__u8 struct_v;		/* compat */
+	__u8 struct_compat;
+	__le32 struct_len;
+	__le64 max_bytes;	/* quota max. bytes */
+	__le64 max_files;	/* quota max. files */
+} __attribute__ ((packed));
+
 #endif

net/ceph/ceph_common.c

@@ -80,6 +80,7 @@ const char *ceph_msg_type_name(int type)
 	case CEPH_MSG_CLIENT_REPLY: return "client_reply";
 	case CEPH_MSG_CLIENT_CAPS: return "client_caps";
 	case CEPH_MSG_CLIENT_CAPRELEASE: return "client_cap_release";
+	case CEPH_MSG_CLIENT_QUOTA: return "client_quota";
 	case CEPH_MSG_CLIENT_SNAP: return "client_snap";
 	case CEPH_MSG_CLIENT_LEASE: return "client_lease";
 	case CEPH_MSG_POOLOP_REPLY: return "poolop_reply";