Retry opening loop device
If more than the default number of loop devices is in use, we may need
to wait for the device path to be available.
Bug: 128873591
Bug: 122059364
Test: Set up adopted virtual disk and check that it loads on boot
Change-Id: I201dcc32043664076f50b0d6f40de6e5e1a65342
diff --git a/Loop.cpp b/Loop.cpp
index 4926ea8..fa8f8ba 100644
--- a/Loop.cpp
+++ b/Loop.cpp
@@ -45,6 +45,7 @@
using android::base::unique_fd;
static const char* kVoldPrefix = "vold:";
+static constexpr size_t kLoopDeviceRetryAttempts = 3u;
int Loop::create(const std::string& target, std::string& out_device) {
unique_fd ctl_fd(open("/dev/loop-control", O_RDWR | O_CLOEXEC));
@@ -61,7 +62,14 @@
out_device = StringPrintf("/dev/block/loop%d", num);
- unique_fd target_fd(open(target.c_str(), O_RDWR | O_CLOEXEC));
+ unique_fd target_fd;
+ for (size_t i = 0; i != kLoopDeviceRetryAttempts; ++i) {
+ target_fd.reset(open(target.c_str(), O_RDWR | O_CLOEXEC));
+ if (target_fd.get() != -1) {
+ break;
+ }
+ usleep(50000);
+ }
if (target_fd.get() == -1) {
PLOG(ERROR) << "Failed to open " << target;
return -errno;