From bdab511d954a849d06e34f6d801cc374f867213b Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@mit.edu>
Date: Sun, 21 Feb 2016 23:05:22 -0500
Subject: Implement statfs

---
 src/operations.cc   | 14 ++++++++++++++
 src/posix_extras.cc |  7 +++++++
 src/posix_extras.h  |  5 +++++
 3 files changed, 26 insertions(+)

diff --git a/src/operations.cc b/src/operations.cc
index 79d2d07..cf53b05 100644
--- a/src/operations.cc
+++ b/src/operations.cc
@@ -33,6 +33,7 @@
 #include <fcntl.h>
 #include <glog/logging.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <sys/types.h>
 #include <time.h>
 
@@ -61,6 +62,17 @@ void* Initialize(fuse_conn_info*) noexcept { return nullptr; }
 
 void Destroy(void*) noexcept {}
 
+int Statfs(const char* const c_path, struct statvfs* const output) {
+  const std::string path(c_path);
+  if (path == "/") {
+    *output = root_->StatVFs();
+  } else {
+    *output =
+        root_->OpenAt(EncodePath(path).c_str(), O_RDONLY | O_PATH).StatVFs();
+  }
+  return 0;
+}
+
 int Getattr(const char* const c_path, struct stat* output) {
   const std::string path(c_path);
   if (path == "/") {
@@ -276,6 +288,8 @@ fuse_operations FuseOperations(File* const root) {
   result.init = Initialize;
   result.destroy = Destroy;
 
+  result.statfs = CATCH_AND_RETURN_EXCEPTIONS(Statfs);
+
   result.getattr = CATCH_AND_RETURN_EXCEPTIONS(Getattr);
   result.fgetattr = CATCH_AND_RETURN_EXCEPTIONS(Fgetattr);
 
diff --git a/src/posix_extras.cc b/src/posix_extras.cc
index c0a5234..3e916ad 100644
--- a/src/posix_extras.cc
+++ b/src/posix_extras.cc
@@ -27,6 +27,7 @@
 #include <glog/logging.h>
 #include <stdio.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -149,6 +150,12 @@ void File::RmDirAt(const char* const path) const {
   CheckSyscall(unlinkat(fd_, path, AT_REMOVEDIR));
 }
 
+struct statvfs File::StatVFs() const {
+  struct statvfs result;
+  CheckSyscall(fstatvfs(fd_, &result));
+  return result;
+}
+
 void File::SymLinkAt(const char* const target, const char* const source) const {
   ValidatePath(source);
   CheckSyscall(symlinkat(target, fd_, source));
diff --git a/src/posix_extras.h b/src/posix_extras.h
index b67e2b4..9dec22d 100644
--- a/src/posix_extras.h
+++ b/src/posix_extras.h
@@ -22,6 +22,7 @@
 
 #include <dirent.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <sys/types.h>
 #include <time.h>
 
@@ -107,6 +108,10 @@ class File {
   // path must indeed be relative (i.e., it must not start with '/').
   void RmDirAt(const char* path) const;
 
+  // Retrieves information about the file system containing the referent of the
+  // file descriptor.
+  struct statvfs StatVFs() const;
+
   // Creates a symlink at source pointing to target.  target is unvalidated.
   // source is interpreted as a path relative to the file descriptor and must
   // indeed be relative (i.e., it must not start with '/').
-- 
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