[PATCH] xfs: fix Q_XQUOTARM ioctl

[Eric Sandeen]

The Q_XQUOTARM quotactl was not working properly, because
we weren't passing around proper flags.  The xfs_fs_set_xstate()
ioctl handler used the same flags for Q_XQUOTAON/OFF as
well as for Q_XQUOTARM, but Q_XQUOTAON/OFF look for
XFS_UQUOTA_ACCT, XFS_UQUOTA_ENFD, XFS_GQUOTA_ACCT etc,
i.e. quota type + state, while Q_XQUOTARM looks only for
the type of quota, i.e. XFS_DQ_USER, XFS_DQ_GROUP etc.

Unfortunately these flag spaces overlap a bit, so we
got semi-random results for Q_XQUOTARM; i.e. the value
for XFS_DQ_USER == XFS_UQUOTA_ACCT, etc.  yeargh.

Split out the flag conversion from userspace to kernelspace,
depending on the quotactl that is being executed; add 2 new
helpers to do this, so that we send the right flags to the
lower-level functions.

This has been broken more or less forever, AFAICT.

Signed-off-by: Eric Sandeen <sandeen at redhat.com>
---

diff --git a/fs/xfs/xfs_quotaops.c b/fs/xfs/xfs_quotaops.c
index af33caf..6f14b8f 100644
--- a/fs/xfs/xfs_quotaops.c
+++ b/fs/xfs/xfs_quotaops.c
@@ -66,19 +66,11 @@ xfs_fs_get_xstatev(
 	return -xfs_qm_scall_getqstatv(mp, fqs);
 }
 
+/* Convert quotactl flags to internal flags for Q_XQUOTAON/OFF */
 STATIC int
-xfs_fs_set_xstate(
-	struct super_block	*sb,
-	unsigned int		uflags,
-	int			op)
+xfs_qm_import_flags(unsigned int uflags)
 {
-	struct xfs_mount	*mp = XFS_M(sb);
-	unsigned int		flags = 0;
-
-	if (sb->s_flags & MS_RDONLY)
-		return -EROFS;
-	if (op != Q_XQUOTARM && !XFS_IS_QUOTA_RUNNING(mp))
-		return -ENOSYS;
+	unsigned int flags = 0;
 
 	if (uflags & FS_QUOTA_UDQ_ACCT)
 		flags |= XFS_UQUOTA_ACCT;
@@ -93,16 +85,52 @@ xfs_fs_set_xstate(
 	if (uflags & FS_QUOTA_PDQ_ENFD)
 		flags |= XFS_PQUOTA_ENFD;
 
+	return flags;
+}
+
+/* Convert quotactl flags to internal flags for Q_XQUOTARM */
+STATIC int
+xfs_qm_import_qtype_flags(unsigned int uflags)
+{
+	unsigned int flags = 0;
+
+	if (uflags & FS_USER_QUOTA)
+		flags |= XFS_DQ_USER;
+	if (uflags & FS_GROUP_QUOTA)
+		flags |= XFS_DQ_GROUP;
+	if (uflags & FS_USER_QUOTA)
+		flags |= XFS_DQ_PROJ;
+
+	return flags;
+}
+
+STATIC int
+xfs_fs_set_xstate(
+	struct super_block	*sb,
+	unsigned int		uflags,
+	int			op)
+{
+	struct xfs_mount	*mp = XFS_M(sb);
+	unsigned int		flags;
+
+	if (sb->s_flags & MS_RDONLY)
+		return -EROFS;
+	if (op != Q_XQUOTARM && !XFS_IS_QUOTA_RUNNING(mp))
+		return -ENOSYS;
+
 	switch (op) {
 	case Q_XQUOTAON:
+		flags = xfs_qm_import_flags(uflags);
 		return -xfs_qm_scall_quotaon(mp, flags);
 	case Q_XQUOTAOFF:
 		if (!XFS_IS_QUOTA_ON(mp))
 			return -EINVAL;
+		flags = xfs_qm_import_flags(uflags);
 		return -xfs_qm_scall_quotaoff(mp, flags);
 	case Q_XQUOTARM:
 		if (XFS_IS_QUOTA_ON(mp))
 			return -EINVAL;
+		flags = xfs_qm_import_qtype_flags(uflags);
 		return -xfs_qm_scall_trunc_qfiles(mp, flags);
 	}