xfs: fix Q_XQUOTARM ioctl

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.

Add a new quotactl op vector specifically for the QUOTARM
operation, since it operates with a different flag space.

This has been broken more or less forever, AFAICT.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

3 files changed, 39 insertions, 5 deletions

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 2b363e23f36e..ff3f0b3cfdb3 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -278,6 +278,17 @@ static int quota_getxquota(struct super_block *sb, int type, qid_t id,
         return ret;
 }
 
+static int quota_rmxquota(struct super_block *sb, void __user *addr)
+{
+        __u32 flags;
+
+        if (copy_from_user(&flags, addr, sizeof(flags)))
+                return -EFAULT;
+        if (!sb->s_qcop->rm_xquota)
+                return -ENOSYS;
+        return sb->s_qcop->rm_xquota(sb, flags);
+}
+
 /* Copy parameters and call proper function */
 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
                        void __user *addr, struct path *path)
@@ -316,8 +327,9 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
                 return sb->s_qcop->quota_sync(sb, type);
         case Q_XQUOTAON:
         case Q_XQUOTAOFF:
-        case Q_XQUOTARM:
                 return quota_setxstate(sb, cmd, addr);
+        case Q_XQUOTARM:
+                return quota_rmxquota(sb, addr);
         case Q_XGETQSTAT:
                 return quota_getxstate(sb, addr);
         case Q_XGETQSTATV:
diff --git a/fs/xfs/xfs_quotaops.c b/fs/xfs/xfs_quotaops.c
index af33cafe69b6..2ad1b9822e92 100644
--- a/fs/xfs/xfs_quotaops.c
+++ b/fs/xfs/xfs_quotaops.c
@@ -100,16 +100,36 @@ xfs_fs_set_xstate(
                 if (!XFS_IS_QUOTA_ON(mp))
                         return -EINVAL;
                 return -xfs_qm_scall_quotaoff(mp, flags);
-        case Q_XQUOTARM:
-                if (XFS_IS_QUOTA_ON(mp))
-                        return -EINVAL;
-                return -xfs_qm_scall_trunc_qfiles(mp, flags);
         }
 
         return -EINVAL;
 }
 
 STATIC int
+xfs_fs_rm_xquota(
+        struct super_block      *sb,
+        unsigned int            uflags)
+{
+        struct xfs_mount        *mp = XFS_M(sb);
+        unsigned int            flags = 0;
+        
+        if (sb->s_flags & MS_RDONLY)
+                return -EROFS;
+
+        if (XFS_IS_QUOTA_ON(mp))
+                return -EINVAL;
+
+        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 -xfs_qm_scall_trunc_qfiles(mp, flags);
+}       
+
+STATIC int
 xfs_fs_get_dqblk(
         struct super_block      *sb,
         struct kqid             qid,
@@ -149,6 +169,7 @@ const struct quotactl_ops xfs_quotactl_operations = {
         .get_xstatev            = xfs_fs_get_xstatev,
         .get_xstate             = xfs_fs_get_xstate,
         .set_xstate             = xfs_fs_set_xstate,
+        .rm_xquota              = xfs_fs_rm_xquota,
         .get_dqblk              = xfs_fs_get_dqblk,
         .set_dqblk              = xfs_fs_set_dqblk,
 };
diff --git a/include/linux/quota.h b/include/linux/quota.h
index cc7494a35429..0f3c5d38da1f 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -329,6 +329,7 @@ struct quotactl_ops {
         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 *);
+        int (*rm_xquota)(struct super_block *, unsigned int);
 };
 
 struct quota_format_type {