Initial remote commit

test/tt.sh

@@ -0,0 +1,60 @@
+python3 -c "
+import struct
+
+CHUNK = 128*512
+LV_START = 5120000*512
+BSIZE = 4096
+GDT_ENTRY = 64
+BPG = 32768
+
+def raw_read(virt_offset, length):
+    result = bytearray(length)
+    pos = virt_offset
+    remaining = length
+    with open('/dev/md0','rb') as f:
+        while remaining > 0:
+            group     = pos // (5*CHUNK)
+            in_group  = pos % (5*CHUNK)
+            chunk_idx = in_group // CHUNK
+            intra     = in_group % CHUNK
+            seg_len   = min(CHUNK-intra, remaining)
+            dst_off   = pos - virt_offset
+            if chunk_idx != 4:
+                phys = LV_START + group*4*CHUNK + chunk_idx*CHUNK + intra
+                f.seek(phys)
+                data = f.read(seg_len)
+                result[dst_off:dst_off+len(data)] = data
+            pos += seg_len
+            remaining -= seg_len
+    return bytes(result)
+
+# Read primary GDT (at block 1 = byte 4096)
+# and backup GDT (at block group 1 start + 1 block)
+# Group 1 starts at block 32768, GDT backup at block 32769 = byte 32769*4096
+
+# Read 1000 entries from primary GDT
+primary_gdt = bytearray(raw_read(BSIZE, 1000 * GDT_ENTRY))
+
+# Read 1000 entries from backup GDT at group 1
+backup_start = (BPG + 1) * BSIZE  # block 32769
+backup_gdt = raw_read(backup_start, 1000 * GDT_ENTRY)
+
+print('Comparing primary vs backup GDT entries:')
+mismatches = 0
+zeros = 0
+for i in range(1000):
+    p = primary_gdt[i*GDT_ENTRY:(i+1)*GDT_ENTRY]
+    b = backup_gdt[i*GDT_ENTRY:(i+1)*GDT_ENTRY]
+    p_bb = struct.unpack_from('<I',p,0)[0]
+    b_bb = struct.unpack_from('<I',b,0)[0]
+    if p == bytes(GDT_ENTRY):
+        zeros += 1
+    elif p != b:
+        mismatches += 1
+        if mismatches <= 5:
+            print(f'  Group {i}: primary bb={p_bb} vs backup bb={b_bb}')
+
+print(f'Zero entries in primary: {zeros}/1000')
+print(f'Mismatches: {mismatches}/1000')
+print(f'Backup GDT group 0: bb={struct.unpack_from(\"<I\",backup_gdt,0)[0]}')
+"