vold: fix handling of discs with multiple majors on DirectVolume::getShareDevice()

The method DirectVolume::getShareDevice() returns an invalid device if the partition referenced by
mPartIdx is bad. A bad partition is one where the major/minor numbers on disk don't match what is
expected.

The original major number is stored for bad partitions so the fix attempts to retrieve it and
return it if applicable.

This fix is one part of fixing ICS encryption on the i777 (and possibly other devices) where bad
partitions may exist.

Change-Id: Ic3b05dbf45315bde502c151f53928ca1891483f0

1 files changed, 8 insertions, 0 deletions

diff --git a/DirectVolume.cpp b/DirectVolume.cpp
index fab7c12..e463446 100644
--- a/DirectVolume.cpp
+++ b/DirectVolume.cpp
@@ -72,6 +72,14 @@ dev_t DirectVolume::getDiskDevice() {
 
 dev_t DirectVolume::getShareDevice() {
     if (mPartIdx != -1) {
+#ifdef VOLD_DISC_HAS_MULTIPLE_MAJORS
+        int major = getMajorNumberForBadPartition(mPartIdx);
+        if(major != -1) {
+            SLOGE("getShareDevice() returning correct major: %d, minor: %d", major, mPartMinors[mPartIdx - 1]);
+            return MKDEV(major, mPartMinors[mPartIdx - 1]);
+        }
+        else
+#endif
         return MKDEV(mDiskMajor, mPartIdx);
     } else {
         return MKDEV(mDiskMajor, mDiskMinor);