From: Zhang Yi <yi.zhang@huawei.com>

The Linux kernel (since version 6.17) supports FALLOC_FL_WRITE_ZEROES in
fallocate(2). Add support for FALLOC_FL_WRITE_ZEROES to the fallocate
utility by introducing a new option -w|--write-zeroes.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=278c7d9b5e0c
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
v1->v2:
 - Minor description modification to align with the kernel.

 sys-utils/fallocate.1.adoc | 11 +++++++++--
 sys-utils/fallocate.c      | 20 ++++++++++++++++----
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/sys-utils/fallocate.1.adoc b/sys-utils/fallocate.1.adoc
index 44ee0ef4c..0ec9ff9a9 100644
--- a/sys-utils/fallocate.1.adoc
+++ b/sys-utils/fallocate.1.adoc

@@ -12,7 +12,7 @@ fallocate - preallocate or deallocate space to a file

zeores commands, the alternative way is submitting actual zeroed data,
the specified range will be converted into written extents. The write
zeroes command is typically faster than write actual data if the
device supports unmap write zeroes, the specified range will not be
physically zeroed out on the device.
++
+Options *--keep-size* can not be specified for the write-zeroes
operation.
+
 include::man-common/help-version.adoc[]
 
 == AUTHORS

diff --git a/sys-utils/fallocate.c b/sys-utils/fallocate.c
index 13bf52915..8d37fdad7 100644
--- a/sys-utils/fallocate.c
+++ b/sys-utils/fallocate.c

@@ -40,7 +40,7 @@
 #if defined(HAVE_LINUX_FALLOC_H) && \
     (!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE) || \
      !defined(FALLOC_FL_COLLAPSE_RANGE) || !defined(FALLOC_FL_ZERO_RANGE) || \
-     !defined(FALLOC_FL_INSERT_RANGE))
+     !defined(FALLOC_FL_INSERT_RANGE) || !defined(FALLOC_FL_WRITE_ZEROES))
 # include <linux/falloc.h>	/* non-libc fallback for FALLOC_FL_* flags */
 #endif
 

@@ -65,6 +65,10 @@
 # define FALLOC_FL_INSERT_RANGE		0x20
 #endif
 
+#ifndef FALLOC_FL_WRITE_ZEROES
+# define FALLOC_FL_WRITE_ZEROES		0x80
+#endif
+
 #include "nls.h"
 #include "strutils.h"
 #include "c.h"

@@ -94,6 +98,7 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_(" -o, --offset <num>   offset for range operations, in bytes\n"), out);
 	fputs(_(" -p, --punch-hole     replace a range with a hole (implies -n)\n"), out);
 	fputs(_(" -z, --zero-range     zero and ensure allocation of a range\n"), out);
+	fputs(_(" -w, --write-zeroes   write zeroes and ensure allocation of a range\n"), out);
 #ifdef HAVE_POSIX_FALLOCATE
 	fputs(_(" -x, --posix          use posix_fallocate(3) instead of fallocate(2)\n"), out);
 #endif

@@ -304,6 +309,7 @@ int main(int argc, char **argv)
 	    { "dig-holes",      no_argument,       NULL, 'd' },
 	    { "insert-range",   no_argument,       NULL, 'i' },
 	    { "zero-range",     no_argument,       NULL, 'z' },
+	    { "write-zeroes",   no_argument,       NULL, 'w' },
 	    { "offset",         required_argument, NULL, 'o' },
 	    { "length",         required_argument, NULL, 'l' },
 	    { "posix",          no_argument,       NULL, 'x' },

@@ -312,8 +318,8 @@ int main(int argc, char **argv)
 	};
 
 	static const ul_excl_t excl[] = {	/* rows and cols in ASCII order */
-		{ 'c', 'd', 'i', 'p', 'x', 'z'},
-		{ 'c', 'i', 'n', 'x' },
+		{ 'c', 'd', 'i', 'p', 'w', 'x', 'z'},
+		{ 'c', 'i', 'n', 'w', 'x' },
 		{ 0 }
 	};
 	int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;

@@ -323,7 +329,7 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	close_stdout_atexit();
 
-	while ((c = getopt_long(argc, argv, "hvVncpdizxl:o:", longopts, NULL))
+	while ((c = getopt_long(argc, argv, "hvVncpdizwxl:o:", longopts, NULL))
 			!= -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);

@@ -353,6 +359,9 @@ int main(int argc, char **argv)
 		case 'z':
 			mode |= FALLOC_FL_ZERO_RANGE;
 			break;
+		case 'w':
+			mode |= FALLOC_FL_WRITE_ZEROES;
+			break;
 		case 'x':
 #ifdef HAVE_POSIX_FALLOCATE
 			posix = 1;

@@ -429,6 +438,9 @@ int main(int argc, char **argv)
 			else if (mode & FALLOC_FL_ZERO_RANGE)
 				fprintf(stdout, _("%s: %s (%ju bytes) zeroed.\n"),
 								filename, str, length);
+			else if (mode & FALLOC_FL_WRITE_ZEROES)
+				fprintf(stdout, _("%s: %s (%ju bytes) write zeroed.\n"),