Re: [Libguestfs] [PATCH] make-fs: Don't use du --apparent-size to estimate input size.

вт, 18 лют. 2020 о 10:48 Richard W.M. Jones <rjones(a)redhat.com&gt; пише: > > When calculating the initial size of the disk we must estimate > how much space is taken by the input. This is quite difficult. > > For directories we used ‘du --apparent-size -bs DIR’. This is wrong > because ’-b’ implies ‘--apparent-size --block-size=1’. But also > ‘--apparent-size’ causes du to count the file size rather than number > of blocks used by files. > > If you have a directory containing many small files this usually > underestimates resulting in disk sizes which are far too small to > actually contain the files. > > There's no really good answer here because du can't exactly do what we > want, but we can at least remove this flag. This causes much larger > estimates and therefore much larger virtual disks. > > Thanks: Nikolay Ivanets > --- > make-fs/make-fs.c | 11 +++++------ > 1 file changed, 5 insertions(+), 6 deletions(-) > > diff --git a/make-fs/make-fs.c b/make-fs/make-fs.c > index 5d8c3a385..386142280 100644 > --- a/make-fs/make-fs.c > +++ b/make-fs/make-fs.c > @@ -393,7 +393,7 @@ static int > estimate_input (const char *input, uint64_t *estimate_rtn, char **ifmt_rtn) > { > struct stat statbuf; > - const char *argv[6]; > + const char *argv[5]; > CLEANUP_UNLINK_FREE char *tmpfile = NULL; > CLEANUP_FCLOSE FILE *fp = NULL; > char line[256]; > @@ -424,11 +424,10 @@ estimate_input (const char *input, uint64_t *estimate_rtn, char **ifmt_rtn) > } > > argv[0] = "du"; > - argv[1] = "--apparent-size"; > - argv[2] = "-b"; > - argv[3] = "-s"; > - argv[4] = input; > - argv[5] = NULL; > + argv[1] = "--block-size=1"; > + argv[2] = "-s"; > + argv[3] = input; > + argv[4] = NULL; > > if (exec_command ((char **) argv, tmpfile) == -1) > return -1; > -- > 2.24.1 > That didn't help either. And with sparse files even made things worse: holes are not taken into account now at all. I repeat my thoughts here again: it is all like "cats and rats game". We cannot properly handle all the possible cases. I think we can agree that virt-make-fs MAY fail and it is expected situation. Just let the user know that he need to adjust size manually.