From 9c2d918474c17be0ea143390a821f517f04f790f Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Sat, 8 Aug 2020 20:54:07 +0100
Subject: [PATCH] libdevmapper: always return EEXIST if a task fails because
 the device already exists

Allows concurrent opens to return a usable error instead of EINVAL
---
 lib/libdevmapper.c | 12 +++++++++++-
 lib/setup.c        | 19 ++++++++++++-------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/lib/libdevmapper.c b/lib/libdevmapper.c
index a82163b0..0906bd72 100644
--- a/lib/libdevmapper.c
+++ b/lib/libdevmapper.c
@@ -1305,6 +1305,12 @@ err:
 	return r;
 }
 
+static bool dm_device_exists(struct crypt_device *cd, const char *name)
+{
+	int r = dm_status_device(cd, name);
+	return (r >= 0 || r == -EEXIST);
+}
+
 static int _dm_create_device(struct crypt_device *cd, const char *name, const char *type,
 			     const char *uuid, struct crypt_dm_active_device *dmd)
 {
@@ -1354,8 +1360,11 @@ static int _dm_create_device(struct crypt_device *cd, const char *name, const ch
 	if (_dm_use_udev() && !_dm_task_set_cookie(dmt, &cookie, udev_flags))
 		goto out;
 
-	if (!dm_task_run(dmt))
+	if (!dm_task_run(dmt)) {
+		if (dm_device_exists(cd, name))
+			r = -EEXIST;
 		goto out;
+	}
 
 	if (dm_task_get_info(dmt, &dmi))
 		r = 0;
@@ -1720,6 +1729,7 @@ static int dm_status_dmi(const char *name, struct dm_info *dmi,
 		goto out;
 	}
 
+	r = -EEXIST;
 	dm_get_next_target(dmt, NULL, &start, &length,
 			   &target_type, &params);
 
diff --git a/lib/setup.c b/lib/setup.c
index 52b472a1..d8e665c0 100644
--- a/lib/setup.c
+++ b/lib/setup.c
@@ -4161,21 +4161,26 @@ static int _activate_loopaes(struct crypt_device *cd,
 
 static int _activate_check_status(struct crypt_device *cd, const char *name, unsigned reload)
 {
-	crypt_status_info ci;
+	int r;
 
 	if (!name)
 		return 0;
 
-	ci = crypt_status(cd, name);
-	if (ci == CRYPT_INVALID) {
-		log_err(cd, _("Cannot use device %s, name is invalid or still in use."), name);
-		return -EINVAL;
-	} else if (ci >= CRYPT_ACTIVE && !reload) {
+	r = dm_status_device(cd, name);
+
+	if (r >= 0 && reload)
+		return 0;
+
+	if (r >= 0 || r == -EEXIST) {
 		log_err(cd, _("Device %s already exists."), name);
 		return -EEXIST;
 	}
 
-	return 0;
+	if (r == -ENODEV)
+		return 0;
+
+	log_err(cd, _("Cannot use device %s, name is invalid or still in use."), name);
+	return r;
 }
 
 // activation/deactivation of device mapping