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From 85687833434d50e3f5fd4b849e543eb505bf5a20 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 26 Jan 2016 13:10:59 +0100
Subject: [PATCH 1/2] Scan dquots using Q_GETNEXTQUOTA
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Check for new kernel quotactl Q_GETNEXTQUOTA and if available use it for
scanning all dquot structures.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 quota.h           | 14 ++++++++++++++
 quotaio_generic.c | 34 ++++++++++++++++++++++++++++++++++
 quotaio_generic.h |  4 ++++
 quotaio_meta.c    | 14 +++++++++++++-
 4 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/quota.h b/quota.h
index 0c38427..0607e04 100644
--- a/quota.h
+++ b/quota.h
@@ -63,6 +63,7 @@ typedef int64_t qsize_t;	/* Type in which we store size limitations */
 #define Q_SETINFO  0x800006	/* set information about quota files */
 #define Q_GETQUOTA 0x800007	/* get user quota structure */
 #define Q_SETQUOTA 0x800008	/* set user quota structure */
+#define Q_GETNEXTQUOTA 0x800009	/* get disk limits and usage >= ID */
 
 /*
  * Quota structure used for communication with userspace via quotactl
@@ -91,6 +92,19 @@ struct if_dqblk {
 	u_int32_t dqb_valid;
 };
 
+struct if_nextdqblk {
+	u_int64_t dqb_bhardlimit;
+	u_int64_t dqb_bsoftlimit;
+	u_int64_t dqb_curspace;
+	u_int64_t dqb_ihardlimit;
+	u_int64_t dqb_isoftlimit;
+	u_int64_t dqb_curinodes;
+	u_int64_t dqb_btime;
+	u_int64_t dqb_itime;
+	u_int32_t dqb_valid;
+	u_int32_t dqb_id;
+};
+
 /*
  * Structure used for setting quota information about file via quotactl
  * Following flags are used to specify which fields are valid
diff --git a/quotaio_generic.c b/quotaio_generic.c
index 5001a56..4bdf380 100644
--- a/quotaio_generic.c
+++ b/quotaio_generic.c
@@ -161,3 +161,37 @@ int generic_scan_dquots(struct quota_handle *h,
 	free(dquot);
 	return ret;
 }
+
+int vfs_scan_dquots(struct quota_handle *h,
+		    int (*process_dquot)(struct dquot *dquot, char *dqname))
+{
+	struct dquot *dquot = get_empty_dquot();
+	qid_t id = 0;
+	struct if_nextdqblk kdqblk;
+	int ret;
+
+	dquot->dq_h = h;
+	while (1) {
+		ret = quotactl(QCMD(Q_GETNEXTQUOTA, h->qh_type),
+			       h->qh_quotadev, id, (void *)&kdqblk);
+		if (ret < 0)
+			break;
+
+		/*
+		 * This is a slight hack but we know struct if_dqblk is a
+		 * subset of struct if_nextdqblk
+		 */
+		generic_kern2utildqblk(&dquot->dq_dqb,
+				       (struct if_dqblk *)&kdqblk);
+		dquot->dq_id = kdqblk.dqb_id;
+		ret = process_dquot(dquot, NULL);
+		if (ret < 0)
+			break;
+		id = kdqblk.dqb_id + 1;
+	}
+	free(dquot);
+
+	if (errno == ENOENT)
+		return 0;
+	return ret;
+}
diff --git a/quotaio_generic.h b/quotaio_generic.h
index 5edc11c..a7930f0 100644
--- a/quotaio_generic.h
+++ b/quotaio_generic.h
@@ -27,4 +27,8 @@ int generic_scan_dquots(struct quota_handle *h,
 			int (*process_dquot)(struct dquot *dquot, char *dqname),
 			int (*get_dquot)(struct dquot *dquot));
 
+/* Scan all dquots using kernel quotactl to get existing ids */
+int vfs_scan_dquots(struct quota_handle *h,
+		    int (*process_dquot)(struct dquot *dquot, char *dqname));
+
 #endif
diff --git a/quotaio_meta.c b/quotaio_meta.c
index e52b4f4..ad6ff7a 100644
--- a/quotaio_meta.c
+++ b/quotaio_meta.c
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <stdlib.h>
+#include <errno.h>
 
 #include <sys/types.h>
 
@@ -55,7 +56,18 @@ static int meta_commit_dquot(struct dquot *dquot, int flags)
 
 static int meta_scan_dquots(struct quota_handle *h, int (*process_dquot)(struct dquot *dquot, char *dqname))
 {
-	return generic_scan_dquots(h, process_dquot, vfs_get_dquot);
+	struct if_nextdqblk kdqblk;
+	int ret;
+
+	ret = quotactl(QCMD(Q_GETNEXTQUOTA, h->qh_type), h->qh_quotadev, 0,
+		       (void *)&kdqblk);
+	/*
+	 * Fall back to scanning using passwd if Q_GETNEXTQUOTA is not
+	 * supported
+	 */
+	if (ret < 0 && (errno == ENOSYS || errno == EINVAL))
+		return generic_scan_dquots(h, process_dquot, vfs_get_dquot);
+	return vfs_scan_dquots(h, process_dquot);
 }
 
 struct quotafile_ops quotafile_ops_meta = {
-- 
2.5.0