discover: Mount snapshots for all eligible disk devices

[petitboot] / discover / device-handler.c

diff --git a/discover/device-handler.c b/discover/device-handler.c
index cd16399c4bd175d5a2f63c920772b00fafcfe940..31cbcc2c1da50b87b9b5bf472227ebe2ce8559ab 100644 (file)
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -26,6 +26,7 @@
 
 #include "device-handler.h"
 #include "discover-server.h"
+#include "devmapper.h"
 #include "user-event.h"
 #include "platform.h"
 #include "event.h"
@@ -1237,14 +1238,22 @@ static const char *fs_parameters(unsigned int rw_flags, const char *fstype)
        return "";
 }
 
+static inline const char *get_device_path(struct discover_device *dev)
+{
+       return dev->ramdisk ? dev->ramdisk->snapshot : dev->device_path;
+}
+
 static bool check_existing_mount(struct discover_device *dev)
 {
        struct stat devstat, mntstat;
+       const char *device_path;
        struct mntent *mnt;
        FILE *fp;
        int rc;
 
-       rc = stat(dev->device_path, &devstat);
+       device_path = get_device_path(dev);
+
+       rc = stat(device_path, &devstat);
        if (rc) {
                pb_debug("%s: stat failed: %s\n", __func__, strerror(errno));
                return false;
@@ -1294,7 +1303,7 @@ static bool check_existing_mount(struct discover_device *dev)
 
 static int mount_device(struct discover_device *dev)
 {
-       const char *fstype;
+       const char *fstype, *device_path;
        int rc;
 
        if (!dev->device_path)
@@ -1326,9 +1335,11 @@ static int mount_device(struct discover_device *dev)
                goto err_free;
        }
 
+       device_path = get_device_path(dev);
+
        pb_log("mounting device %s read-only\n", dev->device_path);
        errno = 0;
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+       rc = mount(device_path, dev->mount_path, fstype,
                        MS_RDONLY | MS_SILENT,
                        fs_parameters(MS_RDONLY, fstype));
        if (!rc) {
@@ -1339,7 +1350,10 @@ static int mount_device(struct discover_device *dev)
        }
 
        pb_log("couldn't mount device %s: mount failed: %s\n",
-                       dev->device_path, strerror(errno));
+                       device_path, strerror(errno));
+
+       /* If mount fails clean up any snapshot */
+       devmapper_destroy_snapshot(dev);
 
        pb_rmdir_recursive(mount_base(), dev->mount_path);
 err_free:
@@ -1350,17 +1364,21 @@ err_free:
 
 static int umount_device(struct discover_device *dev)
 {
+       const char *device_path;
        int rc;
 
        if (!dev->mounted || !dev->unmount)
                return 0;
 
-       pb_log("unmounting device %s\n", dev->device_path);
+       device_path = get_device_path(dev);
+
+       pb_log("unmounting device %s\n", device_path);
        rc = umount(dev->mount_path);
        if (rc)
                return -1;
 
        dev->mounted = false;
+       devmapper_destroy_snapshot(dev);
 
        pb_rmdir_recursive(mount_base(), dev->mount_path);
 
@@ -1372,7 +1390,7 @@ static int umount_device(struct discover_device *dev)
 
 int device_request_write(struct discover_device *dev, bool *release)
 {
-       const char *fstype;
+       const char *fstype, *device_path;
        int rc;
 
        *release = false;
@@ -1385,14 +1403,18 @@ int device_request_write(struct discover_device *dev, bool *release)
 
        fstype = discover_device_get_param(dev, "ID_FS_TYPE");
 
-       pb_log("remounting device %s read-write\n", dev->device_path);
+       device_path = get_device_path(dev);
+
+       pb_log("remounting device %s read-write\n", device_path);
 
        rc = umount(dev->mount_path);
        if (rc) {
-               pb_log("Failed to unmount %s\n", dev->mount_path);
+               pb_log("Failed to unmount %s: %s\n",
+                      dev->mount_path, strerror(errno));
                return -1;
        }
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+
+       rc = mount(device_path, dev->mount_path, fstype,
                        MS_SILENT,
                        fs_parameters(MS_REMOUNT, fstype));
        if (rc)
@@ -1403,29 +1425,50 @@ int device_request_write(struct discover_device *dev, bool *release)
        return 0;
 
 mount_ro:
-       pb_log("Unable to remount device %s read-write\n", dev->device_path);
-       rc = mount(dev->device_path, dev->mount_path, fstype,
+       pb_log("Unable to remount device %s read-write: %s\n",
+              device_path, strerror(errno));
+       if (mount(device_path, dev->mount_path, fstype,
                        MS_RDONLY | MS_SILENT,
-                       fs_parameters(MS_RDONLY, fstype));
-       if (rc)
-               pb_log("Unable to recover mount for %s\n", dev->device_path);
+                       fs_parameters(MS_RDONLY, fstype)))
+               pb_log("Unable to recover mount for %s: %s\n",
+                      device_path, strerror(errno));
        return -1;
 }
 
 void device_release_write(struct discover_device *dev, bool release)
 {
-       const char *fstype;
+       const char *fstype, *device_path;
+       int rc = 0;
 
        if (!release)
                return;
 
+       device_path = get_device_path(dev);
+
        fstype = discover_device_get_param(dev, "ID_FS_TYPE");
 
-       pb_log("remounting device %s read-only\n", dev->device_path);
-       mount(dev->device_path, dev->mount_path, "",
-                       MS_REMOUNT | MS_RDONLY | MS_SILENT,
+       pb_log("remounting device %s read-only\n", device_path);
+
+       if (umount(dev->mount_path)) {
+               pb_log("Failed to unmount %s\n", dev->mount_path);
+               return;
+       }
+       dev->mounted_rw = dev->mounted = false;
+
+       if (dev->ramdisk) {
+               devmapper_merge_snapshot(dev);
+               /* device_path becomes stale after merge */
+               device_path = get_device_path(dev);
+       }
+
+       mount(device_path, dev->mount_path, fstype,
+                       MS_RDONLY | MS_SILENT,
                        fs_parameters(MS_RDONLY, fstype));
-       dev->mounted_rw = false;
+       if (rc)
+               pb_log("Failed to remount %s read-only: %s\n",
+                      device_path, strerror(errno));
+       else
+               dev->mounted = true;
 }
 
 #else