Use snap device in cow manager initialization

dist/dattobd.spec

@@ -473,7 +473,7 @@ fi
 if [ ! -d %{_systemd_services}/reboot.target.wants/ ]; then
    mkdir -p %{_systemd_services}/reboot.target.wants
 fi   
-ln -s %{_systemd_services}/umount-rootfs.service   %{_systemd_services}/reboot.target.wants/umount-rootfs.service 
+ln -fs %{_systemd_services}/umount-rootfs.service   %{_systemd_services}/reboot.target.wants/umount-rootfs.service 
 
 %postun -n %{libname}
 /sbin/ldconfig
@@ -517,7 +517,7 @@ rm -rf %{buildroot}
 
 
 %post 
-ln -s %{_systemd_services}/umount-rootfs.service   %{_systemd_services}/reboot.target.wants/umount-rootfs.service 
+ln -fs %{_systemd_services}/umount-rootfs.service   %{_systemd_services}/reboot.target.wants/umount-rootfs.service 
 
 %doc README.md doc/STRUCTURE.md
 %if "%{_vendor}" == "redhat"

src/bdev_state_handler.c

@@ -28,7 +28,7 @@ void auto_transition_active(unsigned int minor, const char *dir_name)
 {
         struct snap_device *dev = snap_devices[minor];
 
-LOG_DEBUG("ENTER %s minor: %d", __func__, minor);
+        LOG_DEBUG("ENTER %s minor: %d", __func__, minor);
         mutex_lock(&ioctl_mutex);
 
         if (test_bit(UNVERIFIED, &dev->sd_state)) {
@@ -107,8 +107,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
         struct snap_device *dev;
         struct block_device *cur_bdev;
 
-        LOG_DEBUG("ENTER __handle_bdev_mount_writable");
-
+        LOG_DEBUG("ENTER %s", __func__);
         tracer_for_each(dev, i)
         {
                 if (!dev || test_bit(ACTIVE, &dev->sd_state) ||
@@ -159,7 +158,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
         ret = -ENODEV;
 
 out:
-        LOG_DEBUG("EXIT __handle_bdev_mount_writable");
+        LOG_DEBUG("EXIT %s", __func__);
         *idx_out = i;
         return ret;
 }
@@ -194,6 +193,10 @@ int handle_bdev_mount_event(const char *dir_name, int follow_flags,
 #else
         ret = user_path_at(AT_FDCWD, dir_name, lookup_flags, &path);
 #endif //LINUX_VERSION_CODE
+        if (ret) {
+                LOG_DEBUG("error finding path");
+                goto out;
+        }
 
         LOG_DEBUG("path->dentry: %s, path->mnt->mnt_root: %s", path.dentry->d_name.name, path.mnt->mnt_root->d_name.name);
 
@@ -245,10 +248,10 @@ void post_umount_check(int dormant_ret, int umount_ret, unsigned int idx,
         struct snap_device *dev;
         struct super_block *sb;
 
-        //LOG_DEBUG("ENTER %s", __func__);
+        LOG_DEBUG("ENTER %s", __func__);
         // if we didn't do anything or failed, just return
-        if (dormant_ret){
-                //LOG_DEBUG("dormant_ret");
+        if (dormant_ret) {
+                LOG_DEBUG("EXIT %s, dormant_ret", __func__);
                 return;
         }
         dev = snap_devices[idx];

src/blkdev.c

@@ -166,7 +166,7 @@ void dattobd_drop_super(struct super_block *sb)
 /**
  * dattobd_blkdev_put() - Releases a reference to a block device.
  * This function performs the appropriate action based on the available
- * kernel functions to release or drop the superblock.
+ * kernel functions to release block device.
  *
  * @bd: block device structure pointer to be released.
  *

src/cow_manager.c

@@ -642,6 +642,7 @@ int cow_reload(const char *path, uint64_t elements, unsigned long sect_size,
  * cow_init() - Allocates a &struct cow_manager object and initializes it.
  *              Also creates the COW backing file on disk and writes a
  *              header into it.
+ * @dev:  The &struct snap_device that keeps snapshot device state.
  * @path: The path to the COW file.
  * @elements: typically the number of sectors on the block device.
  * @sect_size: The basic unit of size that the &struct cow_manager works with.
@@ -656,7 +657,7 @@ int cow_reload(const char *path, uint64_t elements, unsigned long sect_size,
  * * 0 - success
  * * !0 - errno indicating the error
  */
-int cow_init(const char *path, uint64_t elements, unsigned long sect_size,
+int cow_init(struct snap_device *dev, const char *path, uint64_t elements, unsigned long sect_size,
              unsigned long cache_size, uint64_t file_max, const uint8_t *uuid,
              uint64_t seqid, struct cow_manager **cm_out)
 {
@@ -691,6 +692,7 @@ int cow_init(const char *path, uint64_t elements, unsigned long sect_size,
                 __cow_calculate_allowed_sects(cache_size, cm->total_sects);
         cm->data_offset = COW_HEADER_SIZE + (cm->total_sects * (sect_size * 8));
         cm->curr_pos = cm->data_offset / COW_BLOCK_SIZE;
+        cm->dev = dev;
 
         if (uuid)
                 memcpy(cm->uuid, uuid, COW_UUID_SIZE);

src/cow_manager.h

@@ -81,7 +81,7 @@ int cow_reload(const char *path, uint64_t elements, unsigned long sect_size,
                unsigned long cache_size, int index_only,
                struct cow_manager **cm_out);
 
-int cow_init(const char *path, uint64_t elements, unsigned long sect_size,
+int cow_init(struct snap_device *dev, const char *path, uint64_t elements, unsigned long sect_size,
              unsigned long cache_size, uint64_t file_max, const uint8_t *uuid,
              uint64_t seqid, struct cow_manager **cm_out);
 

src/tracer.c

@@ -646,7 +646,7 @@ static int __tracer_setup_cow(struct snap_device *dev,
 
                         // create and open the cow manager
                         LOG_DEBUG("creating cow manager");
-                        ret = cow_init(cow_path, SECTOR_TO_BLOCK(size),
+                        ret = cow_init(dev, cow_path, SECTOR_TO_BLOCK(size),
                                        COW_SECTION_SIZE, dev->sd_cache_size,
                                        max_file_size, uuid, seqid,
                                        &dev->sd_cow);
@@ -858,10 +858,11 @@ static void __tracer_copy_cow(const struct snap_device *src,
 {
         dest->sd_cow = src->sd_cow;
         // copy cow file extents and update the device
-	dest->sd_cow_extents = src->sd_cow_extents;
-	dest->sd_cow_ext_cnt = src->sd_cow_ext_cnt;
-
+        dest->sd_cow_extents = src->sd_cow_extents;
+        dest->sd_cow_ext_cnt = src->sd_cow_ext_cnt;
         dest->sd_cow_inode = src->sd_cow_inode;
+        dest->sd_cow->dev = dest;
+
         dest->sd_cache_size = src->sd_cache_size;
         dest->sd_falloc_size = src->sd_falloc_size;
 }