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Mon, 13 Dec 2010 02:36:32 -0700 From: Stefan Hajnoczi To: Date: Mon, 13 Dec 2010 09:36:26 +0000 Message-Id: <1292232986-10913-1-git-send-email-stefanha@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.2.3 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Cc: Kevin Wolf , Christoph Hellwig , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH] qemu-io: Add discard command X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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);