Issue #543: Fix BTRFS mounting issue. (#545)

Issue #543: Fix BTRFS mounting issue.
openmediavault · Dec 25, 2019 · 1c83358 · 1c83358
2 parents 8ef940a + f2a80d8
commit 1c83358
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diff --git a/deb/openmediavault/debian/changelog b/deb/openmediavault/debian/changelog
@@ -2,6 +2,7 @@ openmediavault (5.2.1-1) unstable; urgency=low
 
   * Issue #542: Add OMV_WATCHDOG_CONF_WATCHDOG_TIMEOUT to customize
     the watchdog timeout.
+  * Issue #543: Fix BTRFS mounting issue.
 
  -- Volker Theile <volker.theile@openmediavault.org>  Sun, 22 Dec 2019 22:18:16 +0100
 

diff --git a/deb/openmediavault/usr/share/php/openmediavault/system/filesystem/backend/btrfs.inc b/deb/openmediavault/usr/share/php/openmediavault/system/filesystem/backend/btrfs.inc
@@ -35,15 +35,36 @@ class Btrfs extends BackendAbstract {
 	 * See parent class definition.
 	 */
 	public function enumerateByBlkid(array $enums) {
-		// Sort filesystems by device names.
-		array_sort_key($enums, "devicefile");
-		// Filter filesystems with duplicate UUID, e.g. when they are
-		// used in a RAID. Because of the previous sorting always the
-		// lower device is used.
-		// The following example of a RAID1 will return /dev/sdk.
-		// /dev/sdk: LABEL="TestFS" UUID="b7adba40-b980-4067-b33c-dd5c8ee17044" UUID_SUB="7b19094b-e7df-4a3e-a3db-57e2d4c548b3" TYPE="btrfs"
-		// /dev/sdl: LABEL="TestFS" UUID="b7adba40-b980-4067-b33c-dd5c8ee17044" UUID_SUB="ba1e2b16-5022-4cbd-ad35-6d609e9560e9" TYPE="btrfs"
-		return array_unique_key($enums, "uuid");
+		$result = [];
+		// !!! Attention !!!
+		// We need to keep the following in mind when processing BTRFS
+		// filesystems:
+		// * BTRFS will report multiple devices for a RAID.
+		// * BTRFS seems to randomly use a device file for the canonical
+		//   path from a device of the RAID.
+		//
+		// # blkid
+		// /dev/sdb: LABEL="openmediavaultData" UUID="9b84cea2-3c7b-4f88-b346-f3bc1ee7c804" UUID_SUB="c86b22dd-c08d-47c5-93f3-90bd445931bb" TYPE="btrfs"
+		// /dev/sda: LABEL="openmediavaultData" UUID="9b84cea2-3c7b-4f88-b346-f3bc1ee7c804" UUID_SUB="04c92e67-4e6e-4cfc-bb71-18f9a109aa35" TYPE="btrfs"
+		// /dev/sdc: LABEL="openmediavaultData" UUID="9b84cea2-3c7b-4f88-b346-f3bc1ee7c804" UUID_SUB="9756742b-1552-46ce-9631-8e9376e1a918" TYPE="btrfs"
+		//
+		// # ls -alh /dev/disk/by-label/openmediavaultData
+		// lrwxrwxrwx 1 root root 9 Dec 24 14:05 /dev/disk/by-label/openmediavaultData -> ../../sdc
+		//
+		// Because of that we need to find out the correct device file
+		// and return ONLY that device.
+		// To achieve this, we first filter for unique UUIDs and use
+		// the /dev/disk/by-uuid/<UUID> device file to get the
+		// canonical one. After that simply get the array element
+		// related to that device file.
+		$uniqueEnums = array_unique_key($enums, "uuid");
+		foreach ($uniqueEnums as $uniqueEnumk => $uniqueEnumv) {
+			$canonicalDeviceFile = realpath(sprintf("/dev/disk/by-uuid/%s",
+				$uniqueEnumv['uuid']));
+			$result[] = array_filter_ex($enums, "devicefile",
+				$canonicalDeviceFile)[0];
+		}
+		return $result;
 	}
 
 	/**