ChangeLog, util.c, util.h:

  util.h, util.c (journal_default_size): New function from Andreas
  	Dilger to calculate an appropriate default journal size given a
  	filesystem size.
  util.c (parse_journal_opts): Allow the creation of a journal as small
  	as 1MB.

1 files changed, 23 insertions, 2 deletions

diff --git a/misc/util.c b/misc/util.c
index bf3aabdb..eaf6fea4 100644
--- a/misc/util.c
+++ b/misc/util.c
@@ -164,7 +164,7 @@ void parse_journal_opts(const char *opts)
 			}
 			journal_size = strtoul(arg, &p, 0);
 		journal_size_check:
-			if (*p || (journal_size < 4 || journal_size > 100)) {
+			if (*p || (journal_size < 1 || journal_size > 100)) {
 				fprintf(stderr,
 				_("Invalid journal size parameter - %s.\n"),
 					arg);
@@ -191,8 +191,29 @@ void parse_journal_opts(const char *opts)
 			"\tsize=<journal size in megabytes>\n"
 			"\tdevice=<journal device>\n\n"
 			"Journal size must be between "
-			"4 and 100 megabytes.\n\n" ));
+			"1 and 100 megabytes.\n\n" ));
 		exit(1);
 	}
 }	
 
+/*
+ * Find a reasonable journal file size (in blocks) given the number of blocks
+ * in the filesystem.  For very small filesystems, it is not reasonable to
+ * have a journal that fills more than half of the filesystem.
+ */
+int journal_default_size(blk_t blocks_count)
+{
+	blk_t j_blocks;
+
+	if (blocks_count < 2048) {
+		fprintf(stderr, "Filesystem too small for a journal\n");
+		j_blocks = 0;
+	} else if (blocks_count < 32768)
+		j_blocks = 1024;
+	else if (blocks_count < 262144)
+		j_blocks = 4096;
+	else
+		j_blocks = 8192;
+
+	return j_blocks;
+}