userns: Convert struct dquot dq_id to be a struct kqid

Change struct dquot dq_id to a struct kqid and remove the now
unecessary dq_type.

Make minimal changes to dquot, quota_tree, quota_v1, quota_v2, ext3,
ext4, and ocfs2 to deal with the change in quota structures and
signatures.  The ocfs2 changes are larger than most because of the
extensive tracing throughout the ocfs2 quota code that prints out
dq_id.

quota_tree.c:get_index is modified to take a struct kqid instead of a
qid_t because all of it's callers pass in dquot->dq_id and it allows
me to introduce only a single conversion.

The rest of the changes are either just replacing dq_type with dq_id.type,
adding conversions to deal with the change in type and occassionally
adding qid_eq to allow quota id comparisons in a user namespace safe way.

Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index 0a86e30..332a281 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -95,7 +95,7 @@
 	struct ocfs2_global_disk_dqblk *d = dp;
 	struct mem_dqblk *m = &dquot->dq_dqb;
 
-	d->dqb_id = cpu_to_le32(dquot->dq_id);
+	d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));
 	d->dqb_use_count = cpu_to_le32(OCFS2_DQUOT(dquot)->dq_use_count);
 	d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
 	d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
@@ -112,11 +112,14 @@
 {
 	struct ocfs2_global_disk_dqblk *d = dp;
 	struct ocfs2_mem_dqinfo *oinfo =
-			sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
 
 	if (qtree_entry_unused(&oinfo->dqi_gi, dp))
 		return 0;
-	return le32_to_cpu(d->dqb_id) == dquot->dq_id;
+
+	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
+				le32_to_cpu(d->dqb_id)),
+		      dquot->dq_id);
 }
 
 struct qtree_fmt_operations ocfs2_global_ops = {
@@ -475,7 +478,7 @@
 {
 	int err, err2;
 	struct super_block *sb = dquot->dq_sb;
-	int type = dquot->dq_type;
+	int type = dquot->dq_id.type;
 	struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
 	struct ocfs2_global_disk_dqblk dqblk;
 	s64 spacechange, inodechange;
@@ -504,7 +507,8 @@
 	olditime = dquot->dq_dqb.dqb_itime;
 	oldbtime = dquot->dq_dqb.dqb_btime;
 	ocfs2_global_disk2memdqb(dquot, &dqblk);
-	trace_ocfs2_sync_dquot(dquot->dq_id, dquot->dq_dqb.dqb_curspace,
+	trace_ocfs2_sync_dquot(from_kqid(&init_user_ns, dquot->dq_id),
+			       dquot->dq_dqb.dqb_curspace,
 			       (long long)spacechange,
 			       dquot->dq_dqb.dqb_curinodes,
 			       (long long)inodechange);
@@ -555,8 +559,8 @@
 	err = ocfs2_qinfo_lock(info, freeing);
 	if (err < 0) {
 		mlog(ML_ERROR, "Failed to lock quota info, losing quota write"
-			       " (type=%d, id=%u)\n", dquot->dq_type,
-			       (unsigned)dquot->dq_id);
+			       " (type=%d, id=%u)\n", dquot->dq_id.type,
+			       (unsigned)from_kqid(&init_user_ns, dquot->dq_id));
 		goto out;
 	}
 	if (freeing)
@@ -591,9 +595,10 @@
 	struct ocfs2_super *osb = OCFS2_SB(sb);
 	int status = 0;
 
-	trace_ocfs2_sync_dquot_helper(dquot->dq_id, dquot->dq_type,
+	trace_ocfs2_sync_dquot_helper(from_kqid(&init_user_ns, dquot->dq_id),
+				      dquot->dq_id.type,
 				      type, sb->s_id);
-	if (type != dquot->dq_type)
+	if (type != dquot->dq_id.type)
 		goto out;
 	status = ocfs2_lock_global_qf(oinfo, 1);
 	if (status < 0)
@@ -643,7 +648,8 @@
 	struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
 	int status = 0;
 
-	trace_ocfs2_write_dquot(dquot->dq_id, dquot->dq_type);
+	trace_ocfs2_write_dquot(from_kqid(&init_user_ns, dquot->dq_id),
+				dquot->dq_id.type);
 
 	handle = ocfs2_start_trans(osb, OCFS2_QWRITE_CREDITS);
 	if (IS_ERR(handle)) {
@@ -677,11 +683,12 @@
 {
 	handle_t *handle;
 	struct ocfs2_mem_dqinfo *oinfo =
-			sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
+			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
 	struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
 	int status = 0;
 
-	trace_ocfs2_release_dquot(dquot->dq_id, dquot->dq_type);
+	trace_ocfs2_release_dquot(from_kqid(&init_user_ns, dquot->dq_id),
+				  dquot->dq_id.type);
 
 	mutex_lock(&dquot->dq_lock);
 	/* Check whether we are not racing with some other dqget() */
@@ -691,7 +698,7 @@
 	if (status < 0)
 		goto out;
 	handle = ocfs2_start_trans(osb,
-		ocfs2_calc_qdel_credits(dquot->dq_sb, dquot->dq_type));
+		ocfs2_calc_qdel_credits(dquot->dq_sb, dquot->dq_id.type));
 	if (IS_ERR(handle)) {
 		status = PTR_ERR(handle);
 		mlog_errno(status);
@@ -733,13 +740,14 @@
 	int ex = 0;
 	struct super_block *sb = dquot->dq_sb;
 	struct ocfs2_super *osb = OCFS2_SB(sb);
-	int type = dquot->dq_type;
+	int type = dquot->dq_id.type;
 	struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
 	struct inode *gqinode = info->dqi_gqinode;
 	int need_alloc = ocfs2_global_qinit_alloc(sb, type);
 	handle_t *handle;
 
-	trace_ocfs2_acquire_dquot(dquot->dq_id, type);
+	trace_ocfs2_acquire_dquot(from_kqid(&init_user_ns, dquot->dq_id),
+				  type);
 	mutex_lock(&dquot->dq_lock);
 	/*
 	 * We need an exclusive lock, because we're going to update use count
@@ -821,12 +829,13 @@
 	int sync = 0;
 	int status;
 	struct super_block *sb = dquot->dq_sb;
-	int type = dquot->dq_type;
+	int type = dquot->dq_id.type;
 	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
 	handle_t *handle;
 	struct ocfs2_super *osb = OCFS2_SB(sb);
 
-	trace_ocfs2_mark_dquot_dirty(dquot->dq_id, type);
+	trace_ocfs2_mark_dquot_dirty(from_kqid(&init_user_ns, dquot->dq_id),
+				     type);
 
 	/* In case user set some limits, sync dquot immediately to global
 	 * quota file so that information propagates quicker */