I didn't end up using this, but somebody else might find
it useful, so sending it.
This change lets us specify punch patterns other than
literally every other block.
i.e. punch-alternating with no options will do:
...HDHDHDHDHDHD...
-i 4 -s 2 will do:
...DDHHDDHHDDHH...
or -i 3 -s 1 will do:
...DDHDDHDDHDDH...
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
V2: don't allow interval of zero, or extra arguments
other than the filename after the parsed options.
diff --git a/src/punch-alternating.c b/src/punch-alternating.c
index 4148622..3503ded 100644
--- a/src/punch-alternating.c
+++ b/src/punch-alternating.c
@@ -11,6 +11,14 @@
#include <string.h>
#include "global.h"
+void usage(char *cmd)
+{
+ printf("Usage: %s [-i interval] [-s size] file\n", cmd);
+ printf("Punches every other block in the file by default,\n");
+ printf("or 'size' blocks every 'interval' blocks with options.\n");
+ exit(1);
+}
+
int main(int argc, char *argv[])
{
struct stat s;
@@ -21,14 +29,32 @@ int main(int argc, char *argv[])
off_t sz;
int mode;
int error;
+ int c;
+ int size = 1; /* punch $SIZE blocks ... */
+ int interval = 2; /* every $INTERVAL blocks */
- if (argc != 2) {
- printf("Usage: %s file\n", argv[0]);
- printf("Punches every other block in the file.\n");
- return 1;
+ while ((c = getopt(argc, argv, "i:s:")) != EOF) {
+ switch (c) {
+ case 'i':
+ interval = atoi(optarg);
+ break;
+ case 's':
+ size = atoi(optarg);
+ break;
+ default:
+ usage(argv[0]);
+ }
}
- fd = open(argv[1], O_WRONLY);
+ if (!interval) {
+ printf("Please specify an interval > 0\n");
+ usage(argv[0]);
+ }
+
+ if (optind != argc - 1)
+ usage(argv[0]);
+
+ fd = open(argv[optind], O_WRONLY);
if (fd < 0)
goto err;
@@ -44,8 +70,8 @@ int main(int argc, char *argv[])
blksz = sf.f_bsize;
mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
- for (offset = 0; offset < sz; offset += blksz * 2) {
- error = fallocate(fd, mode, offset, blksz);
+ for (offset = 0; offset < sz; offset += blksz * interval) {
+ error = fallocate(fd, mode, offset, blksz * size);
if (error)
goto err;
}
--
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