From: Karel Zak <kzak@redhat.com>
Date: Wed, 7 Dec 2022 10:43:20 +0000 (+0100)
Subject: blkdiscard: add extra exit code when device does not support discard
X-Git-Tag: v2.39-rc1~383
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4cf6f545ee28fe468efcb1000704055207cfabcd;p=thirdparty%2Futil-linux.git

blkdiscard: add extra exit code when device does not support discard

Fixes: https://github.com/util-linux/util-linux/issues/1941
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/sys-utils/blkdiscard.8.adoc b/sys-utils/blkdiscard.8.adoc
index 240693d1cd..578f300f73 100644
--- a/sys-utils/blkdiscard.8.adoc
+++ b/sys-utils/blkdiscard.8.adoc
@@ -54,9 +54,23 @@ Display the aligned values of _offset_ and _length_. If the *--step* option is s
 
 include::man-common/help-version.adoc[]
 
+== EXIT STATUS
+
+*blkdiscard* has the following exit status values:
+
+*0*::
+success
+
+*1*::
+failure; incorrect invocation, permissions or any other generic error
+
+*2*::
+failure; since v2.39, the device does not support discard operation
+
 == AUTHORS
 
-mailto:lczerner@redhat.com[Lukas Czerner]
+mailto:lczerner@redhat.com[Lukas Czerner],
+mailto:kzak@redhat.com[Karel Zak]
 
 == SEE ALSO
 
diff --git a/sys-utils/blkdiscard.c b/sys-utils/blkdiscard.c
index e90fdfdb35..68e6f107f9 100644
--- a/sys-utils/blkdiscard.c
+++ b/sys-utils/blkdiscard.c
@@ -48,6 +48,9 @@
 #include "closestream.h"
 #include "monotonic.h"
 
+/* exit() status if discard unsupported by device */
+#define BLKDISCARD_EXIT_NOTSUPP		(EXIT_FAILURE + 1)
+
 #ifndef BLKDISCARD
 # define BLKDISCARD	_IO(0x12,119)
 #endif
@@ -152,6 +155,15 @@ out:
 }
 #endif /* HAVE_LIBBLKID */
 
+static void __attribute__((__noreturn__)) err_on_ioctl(
+			const char *ioctlname, const char *path)
+{
+	int exno = errno == EOPNOTSUPP ?
+			BLKDISCARD_EXIT_NOTSUPP : EXIT_FAILURE;
+
+	err(exno, _("%s: %s ioctl failed"), ioctlname, path);
+}
+
 int main(int argc, char **argv)
 {
 	char *path;
@@ -299,18 +311,20 @@ int main(int argc, char **argv)
 		if (range[0] + range[1] > end)
 			range[1] = end - range[0];
 
+		errno = 0;
+
 		switch (act) {
 		case ACT_ZEROOUT:
 			if (ioctl(fd, BLKZEROOUT, &range))
-				 err(EXIT_FAILURE, _("%s: BLKZEROOUT ioctl failed"), path);
+				err_on_ioctl("BLKZEROOUT", path);
 			break;
 		case ACT_SECURE:
 			if (ioctl(fd, BLKSECDISCARD, &range))
-				err(EXIT_FAILURE, _("%s: BLKSECDISCARD ioctl failed"), path);
+				err_on_ioctl("BLKSECDISCARD", path);
 			break;
 		case ACT_DISCARD:
 			if (ioctl(fd, BLKDISCARD, &range))
-				err(EXIT_FAILURE, _("%s: BLKDISCARD ioctl failed"), path);
+				err_on_ioctl("BLKDISCARD", path);
 			break;
 		}