From 2d50b981898e5a7c35e0f05b68c2dcb70adf8394 Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Mon, 27 Sep 2021 19:57:03 +0200
Subject: [PATCH] btrfs-progs: replace start: add option -K/--nodiscard

The commands initializing a new device (mkfs, device add) do discard by
default, while this is missing from replace start. For parity add the
options with same name and semantics.

Issue: #390
Signed-off-by: David Sterba <dsterba@suse.com>
---
 Documentation/btrfs-replace.asciidoc |  4 ++++
 cmds/replace.c                       | 13 ++++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/Documentation/btrfs-replace.asciidoc b/Documentation/btrfs-replace.asciidoc
index 9cea1caa..c4cabfb4 100644
--- a/Documentation/btrfs-replace.asciidoc
+++ b/Documentation/btrfs-replace.asciidoc
@@ -55,6 +55,10 @@ never allowed to be used as the <targetdev>.
 no background replace.
 --enqueue::::
 wait if there's another exclusive operation running, otherwise continue
+-K|--nodiscard::::
+Do not perform whole device TRIM operation on devices that are capable of that.
+This does not affect discard/trim operation when the filesystem is mounted.
+Please see the mount option 'discard' for that in `btrfs`(5).
 
 *status* [-1] <mount_point>::
 Print status and progress information of a running device replace operation.
diff --git a/cmds/replace.c b/cmds/replace.c
index 8d943361..23f5dcca 100644
--- a/cmds/replace.c
+++ b/cmds/replace.c
@@ -114,8 +114,9 @@ static const char *const cmd_replace_start_usage[] = {
 	"       correct checksum. Devices which are currently mounted are",
 	"       never allowed to be used as the <targetdev>",
 	"-B     do not background",
-	"--enqueue    wait if there's another exclusive operation running,",
-	"             otherwise continue",
+	"--enqueue       wait if there's another exclusive operation running,",
+	"                otherwise continue",
+	"-K|--nodiscard  do not perform whole device TRIM",
 	NULL
 };
 
@@ -141,6 +142,7 @@ static int cmd_replace_start(const struct cmd_struct *cmd,
 	u64 srcdev_size;
 	u64 dstdev_size;
 	bool enqueue = false;
+	bool discard = true;
 
 	optind = 0;
 	while (1) {
@@ -148,16 +150,20 @@ static int cmd_replace_start(const struct cmd_struct *cmd,
 		enum { GETOPT_VAL_ENQUEUE = 256 };
 		static const struct option long_options[] = {
 			{ "enqueue", no_argument, NULL, GETOPT_VAL_ENQUEUE},
+			{ "nodiscard", no_argument, NULL, 'K' },
 			{ NULL, 0, NULL, 0}
 		};
 
-		c = getopt_long(argc, argv, "Brf", long_options, NULL);
+		c = getopt_long(argc, argv, "BKrf", long_options, NULL);
 		if (c < 0)
 			break;
 		switch (c) {
 		case 'B':
 			do_not_background = 1;
 			break;
+		case 'K':
+			discard = false;
+			break;
 		case 'r':
 			avoid_reading_from_srcdev = 1;
 			break;
@@ -297,6 +303,7 @@ static int cmd_replace_start(const struct cmd_struct *cmd,
 		BTRFS_DEVICE_PATH_NAME_MAX);
 	ret = btrfs_prepare_device(fddstdev, dstdev, &dstdev_block_count, 0,
 			PREP_DEVICE_ZERO_END | PREP_DEVICE_VERBOSE |
+			(discard ? PREP_DEVICE_DISCARD : 0) |
 			(zoned ? PREP_DEVICE_ZONED : 0));
 	if (ret)
 		goto leave_with_error;