commit 8da6bcb006f4e4257cdd685e35e910a6334f6cea
author San Mehat <san@google.com> Sat Jan 09 12:24:05 2010 -0800
committer San Mehat <san@google.com> Sat Jan 09 12:24:05 2010 -0800
tree f13b9435711bf6728c1cc09e711db3fb982a6b4a
parent 8d934caeae971d7d08ca33e98dae294eb57c402d

vold: Increase max supported loop devices to 255

Signed-off-by: San Mehat <san@google.com>

Loop.cpp

diff --git a/Loop.cpp b/Loop.cpp
index 064e553..1b3879a 100644
--- a/Loop.cpp
+++ b/Loop.cpp
@@ -20,6 +20,9 @@
 #include <errno.h>
 #include <string.h>
 
+#include <sys/types.h>
+#include <sys/stat.h>
+
 #define LOG_TAG "Vold"
 
 #include <cutils/log.h>
@@ -69,29 +72,41 @@
     return 0;
 }
 
-int Loop::getNextAvailable(char *buffer, size_t len) {
+int Loop::create(const char *loopFile, char *loopDeviceBuffer, size_t len) {
     int i;
     int fd;
     char filename[256];
 
-    memset(buffer, 0, len);
-
     for (i = 0; i < LOOP_MAX; i++) {
         struct loop_info li;
         int rc;
 
         sprintf(filename, "/dev/block/loop%d", i);
 
+        /*
+         * The kernel starts us off with 8 loop nodes, but more
+         * are created on-demand if needed.
+         */
+        mode_t mode = 0660 | S_IFBLK;
+        dev_t dev = (7 << 8) | i;
+        if (mknod(filename, mode, dev) < 0) {
+            if (errno != EEXIST) {
+                LOGE("Error creating loop device node (%s)", strerror(errno));
+                return -1;
+            }
+        }
+
         if ((fd = open(filename, O_RDWR)) < 0) {
             LOGE("Unable to open %s (%s)", filename, strerror(errno));
             return -1;
         }
 
         rc = ioctl(fd, LOOP_GET_STATUS, &li);
-        close(fd);
         if (rc < 0 && errno == ENXIO)
             break;
 
+        close(fd);
+
         if (rc < 0) {
             LOGE("Unable to get loop status for %s (%s)", filename,
                  strerror(errno));
@@ -104,22 +119,11 @@
         errno = ENOSPC;
         return -1;
     }
-    strncpy(buffer, filename, len -1);
-    return 0;
-}
 
-int Loop::create(const char *loopDevice, const char *loopFile) {
-    int fd;
+    strncpy(loopDeviceBuffer, filename, len -1);
+
     int file_fd;
 
-    LOGD("Creating loop for file '%s' into loop device '%s'", loopFile,
-         loopDevice);
-    if ((fd = open(loopDevice, O_RDWR)) < 0) {
-        LOGE("Unable to open loop device %s (%s)", loopDevice,
-             strerror(errno));
-        return -1;
-    }
-
     if ((file_fd = open(loopFile, O_RDWR)) < 0) {
         LOGE("Unable to open %s (%s)", loopFile, strerror(errno));
         close(fd);

Loop.h

diff --git a/Loop.h b/Loop.h
index 540db8b..1ade4f9 100644
--- a/Loop.h
+++ b/Loop.h
@@ -22,12 +22,10 @@
 
 class Loop {
 public:
-    static const int LOOP_MAX = 8;
+    static const int LOOP_MAX = 255;
 public:
-    static int getNextAvailable(char *buffer, size_t len);
     static int lookupActive(const char *loopFile, char *buffer, size_t len);
-  
-    static int create(const char *loopDevice, const char *loopFile);
+    static int create(const char *loopFile, char *loopDeviceBuffer, size_t len);
     static int destroyByDevice(const char *loopDevice);
     static int destroyByFile(const char *loopFile);
     static int createImageFile(const char *file, size_t sizeMb);

VolumeManager.cpp

diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index 1e1f15f..a462196 100644
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -198,12 +198,7 @@
     }
 
     char loopDevice[255];
-    if (Loop::getNextAvailable(loopDevice, sizeof(loopDevice))) {
-        unlink(asecFileName);
-        return -1;
-    }
-
-    if (Loop::create(loopDevice, asecFileName)) {
+    if (Loop::create(asecFileName, loopDevice, sizeof(loopDevice))) {
         LOGE("ASEC loop device creation failed (%s)", strerror(errno));
         unlink(asecFileName);
         return -1;
@@ -327,12 +322,7 @@
 
     char loopDevice[255];
     if (Loop::lookupActive(asecFileName, loopDevice, sizeof(loopDevice))) {
-        if (Loop::getNextAvailable(loopDevice, sizeof(loopDevice))) {
-            LOGE("Unable to find loop device for ASEC mount");
-            return -1;
-        }
-
-        if (Loop::create(loopDevice, asecFileName)) {
+        if (Loop::create(asecFileName, loopDevice, sizeof(loopDevice))) {
             LOGE("ASEC loop device creation failed (%s)", strerror(errno));
             return -1;
         }