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 -- 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
