[PATCH v2] f2fs-tools: add ftruncate command in f2fs_io

[Daeho Jeong <daeho43@gmail.com>]

From: Daeho Jeong <daehojeong@google.com>

add ftruncate command to do file truncate.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
---
v2: update f2fs_io documentation
---
 man/f2fs_io.8           |  3 +++
 tools/f2fs_io/f2fs_io.c | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/man/f2fs_io.8 b/man/f2fs_io.8
index 2ff22f7..648fba6 100644
--- a/man/f2fs_io.8
+++ b/man/f2fs_io.8
@@ -180,6 +180,9 @@ Trigger gc to move data blocks from specified address range
 .TP
 \fBget_advise\fR \fI[file]\fR
 Get i_advise value and info in file
+.TP
+\fBftruncate\fR \fI[length] [file_path]\fR
+Do ftruncate a file in file_path with the length
 .SH AUTHOR
 This version of
 .B f2fs_io
diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
index fa01f8f..08056a9 100644
--- a/tools/f2fs_io/f2fs_io.c
+++ b/tools/f2fs_io/f2fs_io.c
@@ -1887,6 +1887,31 @@ static void do_get_advise(int argc, char **argv, const struct cmd_desc *cmd)
 	printf("\n");
 }
 
+#define ftruncate_desc "ftruncate a file"
+#define ftruncate_help					\
+"f2fs_io ftruncate [length] [file_path]\n\n"	\
+"Do ftruncate a file in file_path with the length\n"	\
+
+static void do_ftruncate(int argc, char **argv, const struct cmd_desc *cmd)
+{
+	int fd, ret;
+	off_t length;
+
+	if (argc != 3) {
+		fputs("Excess arguments\n\n", stderr);
+		fputs(cmd->cmd_help, stderr);
+		exit(1);
+	}
+
+	length = atoll(argv[1]);
+	fd = xopen(argv[2], O_WRONLY, 0);
+
+	ret = ftruncate(fd, length);
+	if (ret < 0)
+		die_errno("ftruncate failed");
+	exit(0);
+}
+
 #define CMD_HIDDEN 	0x0001
 #define CMD(name) { #name, do_##name, name##_desc, name##_help, 0 }
 #define _CMD(name) { #name, do_##name, NULL, NULL, CMD_HIDDEN }
@@ -1932,6 +1957,7 @@ const struct cmd_desc cmd_list[] = {
 	CMD(removexattr),
 	CMD(lseek),
 	CMD(get_advise),
+	CMD(ftruncate),
 	{ NULL, NULL, NULL, NULL, 0 }
 };
 
-- 
2.48.1.711.g2feabab25a-goog