Btrfs (Linux): adds tracking of Btrfs data copy counts

Fixes(?) #1941

Author: CarterLi

src/detection/btrfs/btrfs.h

@@ -9,6 +9,7 @@ typedef struct FFBtrfsDiskUsage
     uint64_t used;
     const char* type;
     bool dup;
+    uint8_t copies; // 1=single/raid0/raid5/raid6, 2=dup/raid1/raid10, 3=raid1c3, 4=raid1c4
 } FFBtrfsDiskUsage;
 
 typedef struct FFBtrfsResult

src/detection/btrfs/btrfs_linux.c

@@ -81,6 +81,15 @@ static const char* detectAllocation(FFBtrfsResult* item, int dfd, FFstrbuf* buff
         item->allocation[index].used = ffStrbufToUInt(buffer, 0); \
     \
     item->allocation[index].dup = faccessat(subfd, #_type "/dup/", F_OK, 0) == 0; \
+    do { \
+        uint8_t _copies = 1; \
+        if (faccessat(subfd, #_type "/raid1c4/", F_OK, 0) == 0) _copies = 4; \
+        else if (faccessat(subfd, #_type "/raid1c3/", F_OK, 0) == 0) _copies = 3; \
+        else if (faccessat(subfd, #_type "/raid1/",   F_OK, 0) == 0) _copies = 2; \
+        else if (faccessat(subfd, #_type "/raid10/",  F_OK, 0) == 0) _copies = 2; \
+        else if (item->allocation[index].dup) _copies = 2; /* DUP on single device */ \
+        item->allocation[index].copies = _copies; \
+    } while(0); \
     \
     item->allocation[index].type = #_type;
 
@@ -90,6 +99,9 @@ static const char* detectAllocation(FFBtrfsResult* item, int dfd, FFstrbuf* buff
 
     #undef FF_BTRFS_DETECT_TYPE
 
+    if (item->allocation[0].copies > 1) // index 0 = data
+        item->totalSize /= item->allocation[0].copies;
+
     return NULL;
 }
 

src/modules/btrfs/btrfs.c

@@ -185,6 +185,7 @@ bool ffGenerateBtrfsJsonResult(FF_MAYBE_UNUSED FFBtrfsOptions* options, yyjson_m
             yyjson_mut_val* item = yyjson_mut_arr_add_obj(doc, allocation);
             yyjson_mut_obj_add_str(doc, item, "type", btrfs->allocation[i].type);
             yyjson_mut_obj_add_bool(doc, item, "dup", btrfs->allocation[i].dup);
+            yyjson_mut_obj_add_uint(doc, item, "copies", btrfs->allocation[i].copies);
             yyjson_mut_obj_add_uint(doc, item, "used", btrfs->allocation[i].used);
             yyjson_mut_obj_add_uint(doc, item, "total", btrfs->allocation[i].total);
         }