Add OS_LINUX ifdef protections around fallocate parts

Summary: fallocate is linux only, so let's protect it with ifdef's

Test Plan: make

Reviewers: sheki, dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D8223

util/env_posix.cc

@@ -332,6 +332,7 @@ class PosixMmapFile : public WritableFile {
     return file_offset_ + used;
   }
 
+#ifdef OS_LINUX
   virtual Status Allocate(off_t offset, off_t len) {
     if (!fallocate(fd_, FALLOC_FL_KEEP_SIZE, offset, len)) {
       return Status::OK();
@@ -339,6 +340,7 @@ class PosixMmapFile : public WritableFile {
       return IOError(filename_, errno);
     }
   }
+#endif
 };
 
 // Use posix write to write data to a file.
@@ -466,6 +468,7 @@ class PosixWritableFile : public WritableFile {
     return filesize_;
   }
 
+#ifdef OS_LINUX
   virtual Status Allocate(off_t offset, off_t len) {
     if (!fallocate(fd_, FALLOC_FL_KEEP_SIZE, offset, len)) {
       return Status::OK();
@@ -473,6 +476,7 @@ class PosixWritableFile : public WritableFile {
       return IOError(filename_, errno);
     }
   }
+#endif
 };
 
 static int LockOrUnlock(const std::string& fname, int fd, bool lock) {

util/posix_logger.h

@@ -14,7 +14,9 @@
 #include <time.h>
 #include <fcntl.h>
 #include <unistd.h>
+#ifdef OS_LINUX
 #include <linux/falloc.h>
+#endif
 #include "leveldb/env.h"
 
 namespace leveldb {
@@ -93,6 +95,7 @@ class PosixLogger : public Logger {
 
       assert(p <= limit);
 
+#ifdef OS_LINUX
       // If this write would cross a boundary of kDebugLogChunkSize
       // space, pre-allocate more space to avoid overly large
       // allocations from filesystem allocsize options.
@@ -106,6 +109,7 @@ class PosixLogger : public Logger {
         fallocate(fd_, FALLOC_FL_KEEP_SIZE, 0,
                   desired_allocation_chunk * kDebugLogChunkSize);
       }
+#endif
 
       fwrite(base, 1, write_size, file_);
       fflush(file_);