On Fri, May 05, 2017 at 12:32:34PM +0800, Eryu Guan wrote:
> On Thu, May 04, 2017 at 01:25:05PM -0500, Eric Sandeen wrote:
> > 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.
> >
> > V3: Ok, don't allow negative intervals or sizes, either.
> >
> >
> >
> > diff --git a/src/punch-alternating.c b/src/punch-alternating.c
> > index 4148622..11aa65c 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 +29,37 @@ 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 */
> > +
> > + 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]);
> > + }
> > + }
> > +
> > + if (interval <= 0) {
> > + printf("interval must be > 0\n");
> > + usage(argv[0]);
> > + }
> >
> > - if (argc != 2) {
> > - printf("Usage: %s file\n", argv[0]);
> > - printf("Punches every other block in the file.\n");
> > - return 1;
> > + if (size < 0) {
> > + printf("size must be >= 0\n");
> > + usage(argv[0]);
>
> Can size be 0? Seems not, otherwise we call fallocate with zero length.
> I got this error if I use "-s 0"
>
> $ ./src/punch-alternating -s 0 -i 8 testfile
> -s: Invalid argument
LOL!
The "perror(argv[1])" in the error clause needs to be updated too.
--D
> And the "-s" part indicates that the perror call in 'err' label should
> be updated too, i.e. argv[1] => argv[optind]
>
> They're simple enough to be fixed at commit time, if you think they're
> sane fixes :)
>
> Thanks,
> Eryu
>
> > }
> >
> > - fd = open(argv[1], O_WRONLY);
> > + if (optind != argc - 1)
> > + usage(argv[0]);
> > +
> > + fd = open(argv[optind], O_WRONLY);
> > if (fd < 0)
> > goto err;
> >
> > @@ -44,8 +75,8 @@ 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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