Merge branch 'maint'

* maint:
  More friendly message when locking the index fails.
  Document git blame --reverse.
  Documentation: Note file formats send-email accepts

Documentation/blame-options.txt

@@ -41,6 +41,13 @@ of lines before or after the line given by <start>.
 -S <revs-file>::
 	Use revs from revs-file instead of calling linkgit:git-rev-list[1].
 
+--reverse::
+	Walk history forward instead of backward. Instead of showing
+	the revision in which a line appeared, this shows the last
+	revision in which a line has existed. This requires a range of
+	revision like START..END where the path to blame exists in
+	START.
+
 -p::
 --porcelain::
 	Show in a format designed for machine consumption.

Documentation/git-blame.txt

@@ -10,7 +10,7 @@ SYNOPSIS
 [verse]
 'git blame' [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-p] [-w] [--incremental] [-L n,m]
             [-S <revs-file>] [-M] [-C] [-C] [--since=<date>]
-            [<rev> | --contents <file>] [--] <file>
+	    [<rev> | --contents <file> | --reverse <rev>] [--] <file>
 
 DESCRIPTION
 -----------

Documentation/git-send-email.txt

@@ -19,6 +19,19 @@ The header of the email is configurable by command line options.  If not
 specified on the command line, the user will be prompted with a ReadLine
 enabled interface to provide the necessary information.
 
+There are two formats accepted for patch files:
+
+1. mbox format files
++
+This is what linkgit:git-format-patch[1] generates.  Most headers and MIME
+formatting are ignored.
+
+2. The original format used by Greg Kroah-Hartman's 'send_lots_of_email.pl'
+script
++
+This format expects the first line of the file to contain the "Cc:" value
+and the "Subject:" of the message as the second line.
+
 
 OPTIONS
 -------

builtin-update-index.c

@@ -742,8 +742,7 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		if (newfd < 0) {
 			if (refresh_flags & REFRESH_QUIET)
 				exit(128);
-			die("unable to create '%s.lock': %s",
-			    get_index_file(), strerror(lock_error));
+			unable_to_lock_index_die(get_index_file(), lock_error);
 		}
 		if (write_cache(newfd, active_cache, active_nr) ||
 		    commit_locked_index(lock_file))

cache.h

@@ -484,6 +484,7 @@ struct lock_file {
 };
 #define LOCK_DIE_ON_ERROR 1
 #define LOCK_NODEREF 2
+extern NORETURN void unable_to_lock_index_die(const char *path, int err);
 extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
 extern int hold_lock_file_for_append(struct lock_file *, const char *path, int);
 extern int commit_lock_file(struct lock_file *);

lockfile.c

@@ -155,11 +155,25 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	return lk->fd;
 }
 
+
+NORETURN void unable_to_lock_index_die(const char *path, int err)
+{
+	if (errno == EEXIST) {
+		die("Unable to create '%s.lock': %s.\n\n"
+		    "If no other git process is currently running, this probably means a\n"
+		    "git process crashed in this repository earlier. Make sure no other git\n"
+		    "process is running and remove the file manually to continue.",
+		    path, strerror(err));
+	} else {
+		die("Unable to create '%s.lock': %s", path, strerror(err));
+	}
+}
+
 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
 {
 	int fd = lock_file(lk, path, flags);
 	if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
-		die("unable to create '%s.lock': %s", path, strerror(errno));
+		unable_to_lock_index_die(path, errno);
 	return fd;
 }