GFS2: Hook gfs2_quota_sync into VFS via gfs2_quotactl_ops

The plan is to add further operations to the gfs2_quotactl_ops
in future patches. The sync operation is easy, so we start with
that one.

We plan to use the XFS quota control functions because they more
closely match the GFS2 ones.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/Kconfig

@@ -8,6 +8,8 @@ config GFS2_FS
 	select FS_POSIX_ACL
 	select CRC32
 	select SLOW_WORK
+	select QUOTA
+	select QUOTACTL
 	help
 	  A cluster filesystem.
 

fs/gfs2/ops_fstype.c

@@ -18,6 +18,7 @@
 #include <linux/mount.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/slow-work.h>
+#include <linux/quotaops.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -1138,6 +1139,8 @@ static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent
 	sb->s_op = &gfs2_super_ops;
 	sb->s_export_op = &gfs2_export_ops;
 	sb->s_xattr = gfs2_xattr_handlers;
+	sb->s_qcop = &gfs2_quotactl_ops;
+	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
 	sb->s_time_gran = 1;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 

fs/gfs2/quota.c

@@ -1378,3 +1378,7 @@ int gfs2_quotad(void *data)
 	return 0;
 }
 
+const struct quotactl_ops gfs2_quotactl_ops = {
+	.quota_sync     = gfs2_quota_sync,
+};
+

fs/gfs2/quota.h

@@ -50,5 +50,6 @@ static inline int gfs2_quota_lock_check(struct gfs2_inode *ip)
 }
 
 extern int gfs2_shrink_qd_memory(int nr, gfp_t gfp_mask);
+extern const struct quotactl_ops gfs2_quotactl_ops;
 
 #endif /* __QUOTA_DOT_H__ */