From: Carlos Maiolino <cem@kernel.org>
Date: Sun, 21 Dec 2025 10:24:50 +0000 (+0100)
Subject: punch-alternating: prevent punching all extents
X-Git-Tag: v2026.01.05~30
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ffd562ecf44aff10b74c35c6f961614db5198ca9;p=xfstests-dev.git

punch-alternating: prevent punching all extents

If by any chance the punch size is >= the interval, we end up punching
everything, zeroing out the file.

As this is not a tool to dealloc the whole file, so force the user to
pass a configuration that won't cause it to happen.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>
---

diff --git a/src/punch-alternating.c b/src/punch-alternating.c
index d2bb4b6a..c555b48d 100644
--- a/src/punch-alternating.c
+++ b/src/punch-alternating.c
@@ -88,6 +88,11 @@ int main(int argc, char *argv[])
 		usage(argv[0]);
 	}
 
+	if (size >= interval) {
+		printf("Interval must be > size\n");
+		usage(argv[0]);
+	}
+
 	if (optind != argc - 1)
 		usage(argv[0]);