3 files changed, 77 insertions, 0 deletions

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index c7314f1771f5..dea86e8967ee 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -27,6 +27,7 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
         case Q_SYNC:
         case Q_GETINFO:
         case Q_XGETQSTAT:
+        case Q_XGETQSTATV:
         case Q_XQUOTASYNC:
                 break;
         /* allow to query information for dquots we "own" */
@@ -217,6 +218,31 @@ static int quota_getxstate(struct super_block *sb, void __user *addr)
         return ret;
 }
 
+static int quota_getxstatev(struct super_block *sb, void __user *addr)
+{
+        struct fs_quota_statv fqs;
+        int ret;
+
+        if (!sb->s_qcop->get_xstatev)
+                return -ENOSYS;
+
+        memset(&fqs, 0, sizeof(fqs));
+        if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
+                return -EFAULT;
+
+        /* If this kernel doesn't support user specified version, fail */
+        switch (fqs.qs_version) {
+        case FS_QSTATV_VERSION1:
+                break;
+        default:
+                return -EINVAL;
+        }
+        ret = sb->s_qcop->get_xstatev(sb, &fqs);
+        if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+                return -EFAULT;
+        return ret;
+}
+
 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
                            void __user *addr)
 {
@@ -293,6 +319,8 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
                 return quota_setxstate(sb, cmd, addr);
         case Q_XGETQSTAT:
                 return quota_getxstate(sb, addr);
+        case Q_XGETQSTATV:
+                return quota_getxstatev(sb, addr);
         case Q_XSETQLIM:
                 return quota_setxquota(sb, type, id, addr);
         case Q_XGETQUOTA:
@@ -317,6 +345,7 @@ static int quotactl_cmd_write(int cmd)
         case Q_GETINFO:
         case Q_SYNC:
         case Q_XGETQSTAT:
+        case Q_XGETQSTATV:
         case Q_XGETQUOTA:
         case Q_XQUOTASYNC:
                 return 0;
diff --git a/include/linux/quota.h b/include/linux/quota.h
index d13371134c59..cc7494a35429 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -328,6 +328,7 @@ struct quotactl_ops {
         int (*set_dqblk)(struct super_block *, struct kqid, struct fs_disk_quota *);
         int (*get_xstate)(struct super_block *, struct fs_quota_stat *);
         int (*set_xstate)(struct super_block *, unsigned int, int);
+        int (*get_xstatev)(struct super_block *, struct fs_quota_statv *);
 };
 
 struct quota_format_type {
diff --git a/include/uapi/linux/dqblk_xfs.h b/include/uapi/linux/dqblk_xfs.h
index 86552807aed9..dcd75cc26196 100644
--- a/include/uapi/linux/dqblk_xfs.h
+++ b/include/uapi/linux/dqblk_xfs.h
@@ -38,6 +38,7 @@
 #define Q_XGETQSTAT     XQM_CMD(5)      /* get quota subsystem status */
 #define Q_XQUOTARM      XQM_CMD(6)      /* free disk space used by dquots */
 #define Q_XQUOTASYNC    XQM_CMD(7)      /* delalloc flush, updates dquots */
+#define Q_XGETQSTATV    XQM_CMD(8)      /* newer version of get quota */
 
 /*
  * fs_disk_quota structure:
@@ -163,4 +164,50 @@ typedef struct fs_quota_stat {
         __u16           qs_iwarnlimit;  /* limit for num warnings */
 } fs_quota_stat_t;
 
+/*
+ * fs_quota_statv is used by Q_XGETQSTATV for a given file system. It provides
+ * a centralized way to get meta information about the quota subsystem. eg.
+ * space taken up for user, group, and project quotas, number of dquots
+ * currently incore.
+ *
+ * This version has proper versioning support with appropriate padding for
+ * future expansions, and ability to expand for future without creating any
+ * backward compatibility issues.
+ *
+ * Q_XGETQSTATV uses the passed in value of the requested version via
+ * fs_quota_statv.qs_version to determine the return data layout of
+ * fs_quota_statv.  The kernel will fill the data fields relevant to that
+ * version.
+ *
+ * If kernel does not support user space caller specified version, EINVAL will
+ * be returned. User space caller can then reduce the version number and retry
+ * the same command.
+ */
+#define FS_QSTATV_VERSION1      1       /* fs_quota_statv.qs_version */
+/*
+ * Some basic information about 'quota files' for Q_XGETQSTATV command
+ */
+struct fs_qfilestatv {
+        __u64           qfs_ino;        /* inode number */
+        __u64           qfs_nblks;      /* number of BBs 512-byte-blks */
+        __u32           qfs_nextents;   /* number of extents */
+        __u32           qfs_pad;        /* pad for 8-byte alignment */
+};
+
+struct fs_quota_statv {
+        __s8                    qs_version;     /* version for future changes */
+        __u8                    qs_pad1;        /* pad for 16bit alignment */
+        __u16                   qs_flags;       /* FS_QUOTA_.* flags */
+        __u32                   qs_incoredqs;   /* number of dquots incore */
+        struct fs_qfilestatv    qs_uquota;      /* user quota information */
+        struct fs_qfilestatv    qs_gquota;      /* group quota information */
+        struct fs_qfilestatv    qs_pquota;      /* project quota information */
+        __s32                   qs_btimelimit;  /* limit for blks timer */
+        __s32                   qs_itimelimit;  /* limit for inodes timer */
+        __s32                   qs_rtbtimelimit;/* limit for rt blks timer */
+        __u16                   qs_bwarnlimit;  /* limit for num warnings */
+        __u16                   qs_iwarnlimit;  /* limit for num warnings */
+        __u64                   qs_pad2[8];     /* for future proofing */
+};
+
 #endif  /* _LINUX_DQBLK_XFS_H */