[libvirt] [PATCH] fs: Add proper switch to create filesystem with overwrite

[John Ferlan]

On 11/16/2016 03:18 AM, Erik Skultety wrote:
> On Tue, Nov 15, 2016 at 03:37:02PM -0500, John Ferlan wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1366460
>>
>> When using the --overwrite switch on a pool-build or pool-create, the
>> The mkfs.ext{2|3|4} commands use mke2fs which requires using the '-F' switch
>> in order to force overwriting the current filesystem on the whole disk.
>>
>> Likewise, the mkfs.vfat command uses mkfs.fat which requires using the '-I'
>> switch in order to force overwriting the current filesystem on the whole disk.
>>
>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>> ---
>>  src/storage/storage_backend_fs.c | 10 +++++++++-
>>  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
>> index 6c8bae2..de0e8d5 100644
>> --- a/src/storage/storage_backend_fs.c
>> +++ b/src/storage/storage_backend_fs.c
>> @@ -712,9 +712,17 @@ virStorageBackendExecuteMKFS(const char *device,
>>  
>>      cmd = virCommandNewArgList(MKFS, "-t", format, NULL);
>>  
>> -    /* use the force, otherwise mkfs.xfs won't overwrite existing fs */
>> +    /* use the force, otherwise mkfs.xfs won't overwrite existing fs.
>> +     * Similarly mkfs.ext2, mkfs.ext3, and mkfs.ext4 require supplying -F
>> +     * and mkfs.vfat uses -I */
>>      if (STREQ(format, "xfs"))
>>          virCommandAddArg(cmd, "-f");
>> +    else if (STREQ(format, "ext2") ||
>> +             STREQ(format, "ext3") ||
>> +             STREQ(format, "ext4"))
>> +        virCommandAddArg(cmd, "-F");
>> +    else if (STREQ(format, "vfat"))
>> +        virCommandAddArg(cmd, "-I");
>>  
>>      virCommandAddArg(cmd, device);
> 
> I'm wondering what about mkfs.btrfs -f..I'm just being curious.
> 

Not in the virStoragePoolFormatFileSystem list (e.g. not supported via
the API's).  I originally added all the ones from mkfs.*, but scaled back.

Tks-

John
> ACK
> 
> Erik
>