X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=store.cc;h=cf3eea952f3f27524450765b1b8fc232594d0bca;hb=3addc0c5e928bc7b0fc6ff1ef8b7dff7263cf3ea;hp=26797b319ed635341d1deeedf6bd161110644590;hpb=ac33ae99de4a6aa9cfaca2f7fd6746758264758e;p=cumulus.git

diff --git a/store.cc b/store.cc
index 26797b3..cf3eea9 100644
--- a/store.cc
+++ b/store.cc
@@ -16,6 +16,7 @@
 #include <fcntl.h>
 #include <time.h>
 
+#include <algorithm>
 #include <list>
 #include <set>
 #include <string>
@@ -24,11 +25,14 @@
 #include "store.h"
 #include "ref.h"
 
+using std::max;
 using std::list;
 using std::set;
 using std::string;
 
-static char *const filter_program[] = {"bzip2", "-c", NULL};
+/* Default filter program is bzip2 */
+const char *filter_program = "bzip2 -c";
+const char *filter_extension = ".bz2";
 
 static void cloexec(int fd)
 {
@@ -110,7 +114,7 @@ int Tarfile::spawn_filter(int fd_out)
         close(fd_out);
 
         /* Exec the filter program. */
-        execvp(filter_program[0], filter_program);
+        execlp("/bin/sh", "/bin/sh", "-c", filter_program, NULL);
 
         /* Should not reach here except for error cases. */
         fprintf(stderr, "Could not exec filter: %m\n");
@@ -169,19 +173,22 @@ void Tarfile::internal_write_object(const string &path,
 }
 
 /* Estimate the size based on the size of the actual output file on disk.
- * However, the filter may not have written all data yet, and in the event that
- * it is buffering data to a large extent, also use */
+ * However, it might be the case that the filter program is buffering all its
+ * data, and might potentially not write a single byte until we have closed
+ * our end of the pipe.  If we don't do so until we see data written, we have
+ * a problem.  So, arbitrarily pick an upper bound on the compression ratio
+ * that the filter will achieve (128:1), and return a size estimate which is
+ * the larger of a) bytes actually seen written to disk, and b) input
+ * bytes/128. */
 size_t Tarfile::size_estimate()
 {
     struct stat statbuf;
 
-    if (fstat(real_fd, &statbuf) == 0) {
-        size_t disk_size = statbuf.st_size;
-
-        if (disk_size >= size / 128)
-            return disk_size;
-    }
+    if (fstat(real_fd, &statbuf) == 0)
+        return max((int64_t)statbuf.st_size, (int64_t)(size / 128));
 
+    /* Couldn't stat the file on disk, so just return the actual number of
+     * bytes, before compression. */
     return size;
 }
 
@@ -199,7 +206,8 @@ ObjectReference TarSegmentStore::write_object(const char *data, size_t len,
 
         segment->name = generate_uuid();
 
-        string filename = path + "/" + segment->name + ".tar.bz2";
+        string filename = path + "/" + segment->name + ".tar";
+        filename += filter_extension;
         segment->file = new Tarfile(filename, segment->name);
 
         segment->count = 0;