Fix unavailability to free memory in cache

src/cow_manager.c

@@ -149,6 +149,7 @@ int __cow_write_section(struct cow_manager *cm, unsigned long sect_idx)
 static int __cow_sync_and_free_sections(struct cow_manager *cm,
                                         unsigned long thresh)
 {
+        LOG_DEBUG("__cow_sync_and_free_sections");
         int ret;
         unsigned long i;
 

src/module_control.c

@@ -42,7 +42,7 @@ int dattobd_may_hook_syscalls = 1;
 unsigned long dattobd_cow_max_memory_default = (300 * 1024 * 1024);
 unsigned int dattobd_cow_fallocate_percentage_default = 10;
 unsigned int dattobd_max_snap_devices = DATTOBD_DEFAULT_SNAP_DEVICES;
-int dattobd_debug = 0;
+int dattobd_debug = 1;
 
 module_param_named(may_hook_syscalls, dattobd_may_hook_syscalls, int, S_IRUGO);
 MODULE_PARM_DESC(may_hook_syscalls,

src/module_threads.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
 /*
- * Copyright (C) 2022 Datto Inc.
+ * Copyright (C) 2024 Datto Inc.
  */
 
 #include "module_threads.h"
@@ -80,6 +80,7 @@ int inc_sset_thread(void *data)
                 // free the sector set
                 kfree(sset);
         }
+        LOG_DEBUG("inc_sset_thread has stopped");
 
         return 0;
 }
@@ -119,11 +120,14 @@ int snap_cow_thread(void *data)
                                 cow_free_members(dev->sd_cow);
                 }
 
+#if defined USE_BDOPS_SUBMIT_BIO && defined HAVE_FOPS_FALLOCATE
+//not having it for .deb causes infinite loop and failure, having this for rpms causes objdump caused by not being able to save cached data during unmounting
                 int should_stop=kthread_should_stop();
                 if(should_stop){
-                        LOG_DEBUG("stopping snap thread in if");
+                        LOG_DEBUG("stopping snap thread in conditional");
                         break;
                 }
+#endif
 
                 if (bio_queue_empty(bq))
                         continue;
@@ -167,7 +171,7 @@ int snap_cow_thread(void *data)
                         bio_free_clone(bio);
                 }
         }
-
+        LOG_DEBUG("snap_cow_thread has stopped");
         return 0;
 }
 

src/tracer.c

@@ -158,6 +158,7 @@ void dattobd_free_request_tracking_ptr(struct snap_device *dev)
                 tracing_ops_put(dev->sd_tracing_ops);
                 dev->sd_tracing_ops=NULL;
         }
+        dev->sd_tracing_ops=NULL;
 #else
         dev->sd_orig_request_fn = NULL;
 #endif
@@ -924,6 +925,7 @@ static void __tracer_bioset_exit(struct snap_device *dev)
                 dev->sd_bioset = NULL;
         }
 #else
+        LOG_DEBUG("freeing bio set");
         bioset_exit(&dev->sd_bioset);
 #endif
 }
@@ -1283,6 +1285,7 @@ static int __tracer_transition_tracing(
                         bdev_name);
 #endif
         }
+        LOG_DEBUG("stopped freezing, smb");
         smp_wmb();
         if(dev){
                 LOG_DEBUG("starting tracing");
@@ -1376,6 +1379,7 @@ static MRF_RETURN_TYPE tracing_fn(struct request_queue *q, struct bio *bio)
                 if (dattobd_bio_op_flagged(bio, DATTOBD_PASSTHROUGH))
                 {
                         dattobd_bio_op_clear_flag(bio, DATTOBD_PASSTHROUGH);
+                        goto call_orig;
                 }
                 else
                 {
@@ -1394,6 +1398,7 @@ static MRF_RETURN_TYPE tracing_fn(struct request_queue *q, struct bio *bio)
 #endif
         } // tracer_for_each(dev, i)
 
+call_orig:
 #ifdef USE_BDOPS_SUBMIT_BIO
         if(orig_fn){
                 orig_fn(bio);