Thank you for reply Anand & Matrin, Okay I understand the intention now. I know it's not the forum to address issues related to mkfs commands But I think, options used should be same across the mkfs.XXX commands. Another irregularity is mkfs.f2fs takes "-l" to apply label, while mkfs.ext4 take "-L" to apply label. If one has to write a common script these cases has to be handled separately.
Anyways thank you for help, Best regards, Ankur -----Original Message----- From: Martin Steigerwald [mailto:mar...@lichtvoll.de] Sent: Monday, December 29, 2014 3:09 PM To: Ankur Tank Cc: Anand Jain; linux-btrfs@vger.kernel.org Subject: Re: btrfs doesn't format eMMC if previous filesystem is ext4 Am Montag, 29. Dezember 2014, 07:15:11 schrieb Ankur Tank: > > -----Original Message----- > > From: Anand Jain [mailto:anand.j...@oracle.com] > > Sent: Monday, December 29, 2014 8:21 AM > > To: Ankur Tank; linux-btrfs@vger.kernel.org > > Subject: Re: btrfs doesn't format eMMC if previous filesystem is > > ext4 > > > > On 12/26/2014 11:24 PM, Ankur Tank wrote: > > > Hi, > > > > > > I wanted to test btrfs on the eMMC of beaglebone black based > > > custom board. > > > > > > Precondition: eMMC is formatted with ext4 filesystem Use case: > > > Format eMMC with mkfs.btrfs -L <label> <dev> > > > > > > Result: > > > Mkfs.btrfs denies formatting eMMC because its existing > > > > > > filesystem > > > > > > # mkfs.btrfs -L "1storage" /dev/mmcblk0p2 > > > /dev/mmcblk0p2 appears to contain an existing filesystem (ext4). > > > Error: Use the -f option to force overwrite. > > > > > > If I add "-f" its possible to format the eMMC. > > > > > > # mkfs.btrfs -f -L "1storage" /dev/mmcblk0p2 Detected a SSD, > > > turning off metadata duplication. Mkfs with -m dup if you want to > > > force metadata duplication. Btrfs v3.17 See > > > http://btrfs.wiki.kernel.org for more information. > > > > > > Performing full device TRIM (1.72GiB) ... > > > Turning ON incompat feature 'extref': increased hardlink limit per > > > file to 65536 [273917.692896] btrfs: device label 1storage devid 1 > > > transid 3 /dev/mmcblk0p2 fs created label 1storage on > > > /dev/mmcblk0p2 > > > > > > nodesize 16384 leafsize 16384 sectorsize 4096 size > > > 1.72GiB > > > > > > I had downloaded debian package from following link > > > https://packages.debian.org/sid/armhf/btrfs-tools/download > > > > > > Is it a bug ? or I am missing something ? > > > > > I don't see any bug. Can you be more specific ? Thanks. > Hi Anand, > > Precondition : Previous filesystem on eMMC was --- ext4---- Use case > : Now format eMMC to btrfs format, using ---mkfs.btrfs--- mkfs.btrfs > denies formatting eMMC telling that eMMC contain an existing filesystem(ext4). > > In my opinion mkfs.btrfs must allow to format eMMC with btrfs even if there > is other filesystem on it. > > mkfs.ext4 and mkfs.f2fs does allow formatting even if eMMC contains some > other file system on it. > > Note: If I add "-f" option mkfs.btrf does allow formatting eMMC to btrfs > filesytem. Thats intended. It is like mkfs.xfs does it as well. And I really like this. Don´t just format an existing filesystem without an explicit request to do so. I always disliked that on Linux / UNIX tools don´t ask at least once for dangerous operations. Well some do very toroughly: merkaba:~> LANG=C apt-get purge bash Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: bash* foomatic-db-engine* WARNING: The following essential packages will be removed. This should NOT be done unless you know exactly what you are doing! bash 0 upgraded, 0 newly installed, 2 to remove and 2 not upgraded. After this operation, 5887 kB disk space will be freed. You are about to do something potentially harmful. To continue type in the phrase 'Yes, do as I say!' ?] Yeah, I know the saying that "root" should know about own actions, yeah I think alias rm="rm -i" is too much and doesn´t do much good cause people are motivated to do "rm -f" then to override it after having been asked a hundred times for each to delete file and if you want, and yeah I think alias rm="rm -I" or how Z-Shell does it, is much better, but heck we are all human beings, so I like being warned on actions that may make a ton of data inaccessible real fast. So if you want to script it, use "-f". :) Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 L&T Technology Services Ltd www.LntTechservices.com<http://www.lnttechservices.com/> This Email may contain confidential or privileged information for the intended recipient (s). If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
