From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=37523 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PS4pv-0006wR-87 for qemu-devel@nongnu.org; Mon, 13 Dec 2010 04:37:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PS4pn-0005fv-W1 for qemu-devel@nongnu.org; Mon, 13 Dec 2010 04:36:44 -0500 Received: from mtagate4.uk.ibm.com ([194.196.100.164]:53034) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PS4pn-0005dd-Ox for qemu-devel@nongnu.org; Mon, 13 Dec 2010 04:36:43 -0500 Received: from d06nrmr1806.portsmouth.uk.ibm.com (d06nrmr1806.portsmouth.uk.ibm.com [9.149.39.193]) by mtagate4.uk.ibm.com (8.13.1/8.13.1) with ESMTP id oBD9aX04012721 for ; Mon, 13 Dec 2010 09:36:33 GMT Received: from d06av05.portsmouth.uk.ibm.com (d06av05.portsmouth.uk.ibm.com [9.149.37.229]) by d06nrmr1806.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oBD9aYD13825872 for ; Mon, 13 Dec 2010 09:36:34 GMT Received: from d06av05.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oBD9aWeK005412 for ; Mon, 13 Dec 2010 02:36:33 -0700 From: Stefan Hajnoczi Date: Mon, 13 Dec 2010 09:36:26 +0000 Message-Id: <1292232986-10913-1-git-send-email-stefanha@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH] qemu-io: Add discard command List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Christoph Hellwig , Stefan Hajnoczi discard [-Cq] off len -- discards a number of bytes at a specified offset discards a range of bytes from the given offset Example: 'discard 512 1k' - discards 1 kilobyte from 512 bytes into the file Discards a segment of the currently open file. -C, -- report statistics in a machine parsable format -q, -- quite mode, do not show I/O statistics Signed-off-by: Stefan Hajnoczi --- qemu-io.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 88 insertions(+), 0 deletions(-) diff --git a/qemu-io.c b/qemu-io.c index ff353eb..9de5361 100644 --- a/qemu-io.c +++ b/qemu-io.c @@ -1394,6 +1394,93 @@ static const cmdinfo_t info_cmd = { .oneline = "prints information about the current file", }; +static void +discard_help(void) +{ + printf( +"\n" +" discards a range of bytes from the given offset\n" +"\n" +" Example:\n" +" 'discard 512 1k' - discards 1 kilobyte from 512 bytes into the file\n" +"\n" +" Discards a segment of the currently open file.\n" +" -C, -- report statistics in a machine parsable format\n" +" -q, -- quite mode, do not show I/O statistics\n" +"\n"); +} + +static int discard_f(int argc, char **argv); + +static const cmdinfo_t discard_cmd = { + .name = "discard", + .altname = "d", + .cfunc = discard_f, + .argmin = 2, + .argmax = -1, + .args = "[-Cq] off len", + .oneline = "discards a number of bytes at a specified offset", + .help = discard_help, +}; + +static int +discard_f(int argc, char **argv) +{ + struct timeval t1, t2; + int Cflag = 0, qflag = 0; + int c, ret; + int64_t offset; + int count; + + while ((c = getopt(argc, argv, "Cq")) != EOF) { + switch (c) { + case 'C': + Cflag = 1; + break; + case 'q': + qflag = 1; + break; + default: + return command_usage(&discard_cmd); + } + } + + if (optind != argc - 2) { + return command_usage(&discard_cmd); + } + + offset = cvtnum(argv[optind]); + if (offset < 0) { + printf("non-numeric length argument -- %s\n", argv[optind]); + return 0; + } + + optind++; + count = cvtnum(argv[optind]); + if (count < 0) { + printf("non-numeric length argument -- %s\n", argv[optind]); + return 0; + } + + gettimeofday(&t1, NULL); + ret = bdrv_discard(bs, offset, count); + gettimeofday(&t2, NULL); + + if (ret < 0) { + printf("discard failed: %s\n", strerror(-ret)); + goto out; + } + + /* Finally, report back -- -C gives a parsable format */ + if (!qflag) { + t2 = tsub(t2, t1); + print_report("discard", &t2, offset, count, count, 1, Cflag); + } + +out: + return 0; +} + static int alloc_f(int argc, char **argv) { @@ -1717,6 +1804,7 @@ int main(int argc, char **argv) add_command(&truncate_cmd); add_command(&length_cmd); add_command(&info_cmd); + add_command(&discard_cmd); add_command(&alloc_cmd); add_command(&map_cmd); -- 1.7.2.3