From f5105bfbfeb4215ae2aa42b1f088821d3ccf161f Mon Sep 17 00:00:00 2001
From: Alexander Rutkovsky <alexvru@ydb.tech>
Date: Thu, 1 Aug 2024 07:24:56 +0000
Subject: [PATCH] Fix block device size calculcation code

---
 ydb/library/pdisk_io/wcache.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/ydb/library/pdisk_io/wcache.cpp b/ydb/library/pdisk_io/wcache.cpp
index 5425c0b020ce..28d22cdd1008 100644
--- a/ydb/library/pdisk_io/wcache.cpp
+++ b/ydb/library/pdisk_io/wcache.cpp
@@ -668,9 +668,15 @@ std::optional<TDriveData> GetDriveData(const TString &path, TStringStream *outDe
     try {
         TFile f(path, OpenExisting | RdOnly);
         TDriveData data;
-        long size = 0;
-        if (ioctl(f.GetHandle(), BLKGETSIZE, &size) == 0) {
-            data.Size = size << 9;
+        if (off64_t off = lseek64(f.GetHandle(), 0, SEEK_END); off != (off64_t)-1) {
+            data.Size = off;
+        } else {
+            long size = 0;
+            if (!ioctl(f.GetHandle(), BLKGETSIZE64, &size)) {
+                data.Size = size;
+            } else if (!ioctl(f.GetHandle(), BLKGETSIZE, &size)) {
+                data.Size = size << 9;
+            }
         }
         EWriteCacheResult res = GetWriteCache(f.GetHandle(), path, &data, outDetails);
         if (res == EWriteCacheResult::WriteCacheResultOk) {