[PATCH 02/15] add a new rw_hint helper

[Christoph Hellwig <hch@lst.de>]

Add a tool to set the life time hint via fcntl.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 .gitignore    |  1 +
 src/Makefile  |  3 ++-
 src/rw_hint.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 src/rw_hint.c

diff --git a/.gitignore b/.gitignore
index 4fd817243dca..f22cff8fb6c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -203,6 +203,7 @@ tags
 /src/aio-dio-regress/aio-last-ref-held-by-io
 /src/aio-dio-regress/aiocp
 /src/aio-dio-regress/aiodio_sparse2
+/src/rw_hint
 /src/vfs/vfstest
 /src/vfs/mount-idmapped
 /src/log-writes/replay-log
diff --git a/src/Makefile b/src/Makefile
index 6ac72b366257..2cc1fb40d9f1 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -35,7 +35,8 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \
 	fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
 	detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \
-	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault min_dio_alignment
+	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault min_dio_alignment \
+	rw_hint
 
 EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
 	      btrfs_crc32c_forged_name.py popdir.pl popattr.py \
diff --git a/src/rw_hint.c b/src/rw_hint.c
new file mode 100644
index 000000000000..d4290e4ae369
--- /dev/null
+++ b/src/rw_hint.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Christoph Hellwig
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+
+int main(int argc, char **argv)
+{
+	uint64_t hint = -1;
+	int fd;
+
+	if (argc < 3) {
+		fprintf(stderr,
+"usage: %s file not_set|none|short|medium|long|extreme\n",
+			argv[0]);
+		return 1;
+	}
+
+	if (!strcmp(argv[2], "not_set"))
+		hint = RWH_WRITE_LIFE_NOT_SET;
+	else if (!strcmp(argv[2], "none"))
+		hint = RWH_WRITE_LIFE_NONE;
+	else if (!strcmp(argv[2], "short"))
+		hint = RWH_WRITE_LIFE_SHORT;
+	else if (!strcmp(argv[2], "medium"))
+		hint = RWH_WRITE_LIFE_MEDIUM;
+	else if (!strcmp(argv[2], "long"))
+		hint = RWH_WRITE_LIFE_LONG;
+	else if (!strcmp(argv[2], "extreme"))
+		hint = RWH_WRITE_LIFE_EXTREME;
+
+	if (hint == -1) {
+		fprintf(stderr, "invalid hint %s\n", argv[2]);
+		return 1;
+	}
+
+	fd = open(argv[1], O_WRONLY);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+	if (fcntl(fd, F_SET_RW_HINT, &hint))
+		perror("fcntl");
+	return 0;
+}
-- 
2.47.2