blktrace: disable kill option - take 2

Fixup for 513950.

Problem:
'blktrace -d <device> -k' does not kill a running
backgound trace. Executing 'blktrace -d <device> -k'
for the second time results in "BLKTRACETEARDOWN:
Invalid argument" message and then each run of
blktrace on that machine prints the following output:
BLKTRACESETUP: No such file or directory.

The bug:
The option -k results in clobbering information
about running trace by kernel (blk_trace_remove),
while resources (files open in debugfs by the running
background blktrace) are not released.

Solution:
Update documentation:
Undocument the non-working "kill" option. Advise
to send SIGINT signall via kill(1) to the running
background blktrace for its correct termination.

Signed-off-by: Edward Shishkin <edward@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/blktrace.c b/blktrace.c
index 660ad7a274f88e985ddd46ca93c27b7a0948f8af..b9f9b689cf65e5de63dd47eff01281633a61a516 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -442,7 +442,6 @@ static char usage_str[] = \
        "\t-r Path to mounted debugfs, defaults to /sys/kernel/debug\n" \
        "\t-o File(s) to send output to\n" \
        "\t-D Directory to prepend to output file names\n" \
-       "\t-k Kill a running trace\n" \
        "\t-w Stop after defined time, in seconds\n" \
        "\t-a Only trace specified actions. See documentation\n" \
        "\t-A Give trace mask as a single value. See documentation\n" \

diff --git a/doc/blktrace.8 b/doc/blktrace.8
index 58e8f905f66d63d6b05b96cb1acca0041c2b629e..ab6a3f3366e9840b1f24aa1159266fee998bb0e2 100644 (file)
--- a/doc/blktrace.8
+++ b/doc/blktrace.8
@@ -66,19 +66,10 @@ blktrace may also be run concurrently with blkparse to produce
 .TP 2
 \- 
 The default behaviour for blktrace is to run forever until explicitly
-killed by the user (via a control-C, or kill utility invocation).
-There are two ways to modify this:
-
-.TP 5
-  1. 
-You may utilise the blktrace utility itself to kill
-a running trace -- via the \fB\-k\fR option.
-
-.TP 5
-  2.
-You can specify a run-time duration for blktrace via the
-\fB\-w\fR option -- then blktrace will run for the specified number
-of seconds, and then halt.
+killed by the user (via a control-C, or sending SIGINT signal to the
+process via invocation the kill (1) utility). Also you can specify a
+run-time duration for blktrace via the \fB\-w\fR option -- then
+blktrace will run for the specified number of seconds, and then halt.
 
 
 .SH OPTIONS
@@ -119,13 +110,6 @@ Adds \fIdev\fR as a device to trace
 Adds the devices found in \fIfile\fR as devices to trace
 .RE
 
-\-k 
-.br
-\-\-kill 
-.RS
-Kill on-going trace  
-.RE
-
 \-n \fInum\-sub\fR 
 .br
 \-\-num\-sub=\fInum-sub\fR