Re: [PATCH 15/19 v3] mkfs: don't treat files as though they are block devices

Eric Sandeen
2016-04-29T19:11:46Z

On 4/29/16 9:47 AM, Jan Tulak wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> If the device is actually a file, and "-d file" is not specified,
> mkfs will try to treat it as a block device and get stuff wrong.
> Image files don't necessarily have the same sector sizes as the
> block device or filesystem underlying the image file, nor should we
> be issuing discard ioctls on image files.
>
> To fix this sanely, only require "-d file" if the device name is
> invalid to trigger creation of the file. Otherwise, use stat() to
> determine if the device is a file or block device and deal with that
> appropriately by setting the "isfile" variables and turning off
> direct IO. Then ensure that we check the "isfile" options before
> doing things that are specific to block devices.
>
> Other file/blockdev issues fixed:
> - use getstr to detect specifying the data device name
> twice.
> - check file/size/name parameters before anything else.
> - overwrite checks need to be done before the image file is
> opened and potentially truncated.
> - blkid_get_topology() should not be called for image files,
> so warn when it is called that way.
> - zero_old_xfs_structures() emits a spurious error:
> "existing superblock read failed: Success"
> when it is run on a truncated image file. Don't warn if we
> see this problem on an image file.
> - Don't issue discards on image files.
> - Use fsync() for image files, not BLKFLSBUF in
> platform_flush_device() for Linux.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Jan Tulak <jtulak@redhat.com>
>
> ---
> CHANGES:
> * read image file size in advance of O_TRUNC in case of dfile&&dcreat
> Signed-off-by: Jan Tulak <jtulak@redhat.com>
> ---
> libxfs/init.c | 21 ++++++-
> libxfs/linux.c | 11 +++-
> mkfs/xfs_mkfs.c | 182 ++++++++++++++++++++++++++++++++++++++------------------
> 3 files changed, 154 insertions(+), 60 deletions(-)
>
> diff --git a/libxfs/init.c b/libxfs/init.c
> index 8d747e8..c7ae00d 100644
> --- a/libxfs/init.c
> +++ b/libxfs/init.c
> @@ -253,8 +253,15 @@ libxfs_init(libxfs_init_t *a)
> rtname = a->rtname;
> a->dfd = a->logfd = a->rtfd = -1;
> a->ddev = a->logdev = a->rtdev = 0;
> - a->dbsize = a->lbsize = a->rtbsize = 0;
> - a->dsize = a->logBBsize = a->logBBstart = a->rtsize = 0;
> + a->lbsize = a->rtbsize = 0;
> + a->logBBsize = a->logBBstart = a->rtsize = 0;
> +
> + // We can reset dbsize only when it is not a file, or we won't
> + // truncate it. Otherwise, we loose the size of the file forever.

please don't use c++ comments in xfsprogs, we use /* comments */

...

> static void
> +check_device_type(
> + const char *name,
> + int *isfile,
> + bool no_size,
> + bool no_name,
> + int *create,
> + bool force_overwrite,
> + const char *optname)
> +{
> + struct stat64 statbuf;
> + /*
> + if (*isfile && (no_size || no_name)) {
> + fprintf(stderr,
> + _("if -%s file then -%s name and -%s size are required\n"),
> + optname, optname, optname);
> + usage();
> + }*/

What is this?

Jan, I'm just going to go back to the original patches posted in your V2 series,
and either give them Reviewed-by's, or send followup fix-up patches with a

Eric Sandeen <sandeen@redhat.com>: fixed up foo, bar, baz

tag and a Reviewed-by to go with it, I think that might be the fastest path to
finally getting this stuff merged.

Thanks,
-Eric