[Backport release-2.27] Show reasons a POSIX file cannot be read (#5432)

tiledb/sm/filesystem/mem_filesystem.cc

@@ -183,8 +183,12 @@ class MemFilesystem::File : public MemFilesystem::FSNode {
     assert(buffer);
 
     if (offset + nbytes > size_)
-      return LOG_STATUS(
-          Status_MemFSError("Cannot read from file; Read exceeds file size"));
+      return LOG_STATUS(Status_MemFSError(fmt::format(
+          "Cannot read from file; Read exceeds file size: offset {} nbytes {} "
+          "size_ {}",
+          offset,
+          nbytes,
+          size_)));
 
     memcpy(buffer, (char*)data_ + offset, nbytes);
     return Status::Ok();

tiledb/sm/filesystem/posix.cc

@@ -273,8 +273,15 @@ void Posix::read(
   auto path = uri.to_path();
   uint64_t file_size;
   this->file_size(URI(path), &file_size);
-  if (offset + nbytes > file_size)
-    throw IOError("Cannot read from file; Read exceeds file size");
+  if (offset + nbytes > file_size) {
+    throw IOError(fmt::format(
+        "Cannot read from file; Read exceeds file size: offset {}, nbytes {}, "
+        "file_size {}, URI {}",
+        offset,
+        nbytes,
+        file_size,
+        uri.to_path()));
+  }
 
   // Open file
   int fd = open(path.c_str(), O_RDONLY);

tiledb/sm/filesystem/win.cc

@@ -58,6 +58,8 @@
 #include "uri.h"
 #include "win.h"
 
+#include <fmt/format.h>
+
 using namespace tiledb::common;
 using tiledb::common::filesystem::directory_entry;
 
@@ -462,11 +464,23 @@ Status Win::read(
         0) {
       auto gle = GetLastError();
       CloseHandle(file_h);
-      return LOG_STATUS(Status_IOError(
-          "Cannot read from file '" + path + "'; File read error " +
-          (gle != 0 ? get_last_error_msg(gle, "ReadFile") :
-                      "num_bytes_read " + std::to_string(num_bytes_read) +
-                          " != nbyes " + std::to_string(nbytes))));
+
+      std::string err_msg;
+      if (gle != 0) {
+        err_msg = get_last_error_msg(gle, "ReadFile");
+      } else {
+        err_msg = std::string("num_bytes_read ") +
+                  std::to_string(num_bytes_read) + " != nbytes " +
+                  std::to_string(nbytes);
+      }
+
+      return LOG_STATUS(Status_IOError(fmt::format(
+          "Cannot read from file '{}'; File read error '{}' offset {} nbytes "
+          "{}",
+          path,
+          err_msg,
+          offset,
+          nbytes)));
     }
     byte_buffer += num_bytes_read;
     offset += num_bytes_read;