Re: [PATCH] Btrfs: initial online fsck support
Excerpts from Andi Kleen's message of 2011-07-02 13:04:43 -0400: The two big features of btrfs are self-healing and online fsck, those have to Are they? be implemented in kernel space. Why? There have been online fscks in user space in the past, e.g. the various schemes using LVM snapshots for ext* and other related work on the BSD FFS. I don't see any principal reason why it couldn't be done for btrfs either. A good fsck is quite complex and you are unlikely to want all that code in kernel space. The offline fsck for btrfs is basically for repairing the worst possible problems (things that make the FS unmountable). The online code can easily take on smaller things, like detecting incorrect link counts and a whole series of other problems that shouldn't require offline access. -chris -- 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
Re: [PATCH] Btrfs: initial online fsck support
On Friday 01 of July 2011 19:48:36 Andi Kleen wrote: Li Zefan l...@cn.fujitsu.com writes: This is an initial version of online fsck. What it does is: - check the dir item and dir index pointing to a file. - check the structure of extents of a file. As furthur work, we should consider: - fix but not only check the structure of a file. - verify the extent allocation tree on the fly. It's scary to have a fsck in kernel space. Is there no way to do this from user space? -Andi There will be a userspace fsck (Chris Mason is working on it ATM). The two big features of btrfs are self-healing and online fsck, those have to be implemented in kernel space. -- Hubert Kario QBS - Quality Business Software 02-656 Warszawa, ul. Ksawerów 30/85 tel. +48 (22) 646-61-51, 646-74-24 www.qbs.com.pl -- 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
Re: [PATCH] Btrfs: initial online fsck support
The two big features of btrfs are self-healing and online fsck, those have to Are they? be implemented in kernel space. Why? There have been online fscks in user space in the past, e.g. the various schemes using LVM snapshots for ext* and other related work on the BSD FFS. I don't see any principal reason why it couldn't be done for btrfs either. A good fsck is quite complex and you are unlikely to want all that code in kernel space. -Andi -- 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
Re: [PATCH] Btrfs: initial online fsck support
On Saturday 02 of July 2011 19:04:43 Andi Kleen wrote: The two big features of btrfs are self-healing and online fsck, those have to Are they? they are scheduled to be, just like RAID5/6, mixed RAID in single FS... be implemented in kernel space. Why? There have been online fscks in user space in the past, e.g. the various schemes using LVM snapshots for ext* and other related work on the BSD FFS. I don't see any principal reason why it couldn't be done for btrfs either. Doing a fsck on LVM snapshot of btrfs: 1. is impossible (UUIDs) 2. won't fix errors I have to note that I don't know how FFS fsck is implemented. A good fsck is quite complex and you are unlikely to want all that code in kernel space. complete one, yes, but it's not quite pointless, ZFS does it like this and admins rather like it -- Hubert Kario QBS - Quality Business Software ul. Ksawerów 30/85 02-656 Warszawa POLAND tel. +48 (22) 646-61-51, 646-74-24 fax +48 (22) 646-61-50 -- 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
Re: [PATCH] Btrfs: initial online fsck support
Li Zefan l...@cn.fujitsu.com writes: This is an initial version of online fsck. What it does is: - check the dir item and dir index pointing to a file. - check the structure of extents of a file. As furthur work, we should consider: - fix but not only check the structure of a file. - verify the extent allocation tree on the fly. It's scary to have a fsck in kernel space. Is there no way to do this from user space? -Andi -- a...@linux.intel.com -- Speaking for myself only -- 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
