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>

1 files changed, 44 insertions, 0 deletions

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index e1c4e0b12b4c..7e72348639e4 100644
--- a/fs/ceph/xattr.c
+++ b/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 */