Eric Sandeen wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=561870
>
> # dd if=/dev/zero of=k bs=1MB count=2 seek=20; mkfs.xfs k
> # mkfs.xfs: probe of k failed, cannot detect existing filesystem.
> # mkfs.xfs: Use the -f option to force overwrite.
>
> blkid fails to do a probe of a regular file.
>
> I wish blkid would cope with this, but for now it might
> be better to just turn it off.
>
> Reported-by: Jim Meyering <meyering@xxxxxxxxxx>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
>
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 9baf116..de87647 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -300,10 +300,15 @@ check_overwrite(
> int fd;
> long long size;
> int bsz;
> + struct stat statbuf;
>
> if (!device || !*device)
> return 0;
>
> + /* blkid can't get info from a regular file */
> + if (!stat(device, &statbuf) && S_ISREG(statbuf.st_mode))
> + return 0;
> +
> ret = -1; /* will reset on success of all setup calls */
>
> fd = open(device, O_RDONLY);
Hi Eric,
Did you consider calling fstat after opening,
rather than "stat" before?
/* blkid can't get info from a regular file */
if (!fstat(fd, &statbuf) && S_ISREG(statbuf.st_mode)) {
close(fd);
return 0;
}
That's slightly more efficient, and not prone to confusion
in the unlikely event that "device" changes inode between
the stat and the open calls.
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