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Date: Mon, 10 Oct 2011 10:20:48 -0700 From: Allison Henderson <achender@...ux.vnet.ibm.com> To: Andreas Dilger <aedilger@...il.com> CC: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>, "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org> Subject: Re: [Ext4 Secure Delete 0/7 v4] Ext4 secure delete On 10/07/2011 10:07 AM, Allison Henderson wrote: > On 10/07/2011 08:21 AM, Andreas Dilger wrote: >> On 2011-10-07, at 1:10 AM, Allison Henderson<achender@...ux.vnet.ibm.com> wrote: >>> Sorry for the delay in getting this next version out. >>> I had some tasks to take care of, and now I'm picking up my >>> secure delete work again. I'm still not quite done yet, >>> but a lot has changed and I wanted to update people so that >>> we have an idea of where its going. Currently the patch >>> deals with data blocks, meta blocks, directory entries, >>> journal blocks, and also provides an option for secure >>> deleting with random data instead of just zeros. >>> I'm also planning on adding some more patches to >>> deal with inodes and also a mount option that turns >>> on secure delete by default. Im still not quite done >>> debugging, but Im just sending it out early to get >>> some more eyes on it. Feed back appreciated! :) >>> >>> v3->v4 >>> Added a new file attribute flag EXT4_SECRM_RANDOM_FL >>> This flag causes the secure delete operations to over write >>> blocks with random data instead of zeros. >> >> Since inode flags are in short supply, and I suspect users that want this want it for all files, this should probably be a superblock flag? >> > That is a really good point. The first thing that comes to mind though would be the fact that it is a lot slower when the random flag is on especially for really big files. So that would be one case where I could imagine a user might want the ability to set different options per file. But since the flags are a limited resource, I can see where we may not want to spend it so quickly. I will see if maybe there is some way I can optimize it, but I would like to see more folks weigh in on this topic too. > I've had another suggestion for this come up, so I wanted to put it out here to see what people think. Instead of a new flag, we could use a flag that is mutually exclusive like the undelete flag, since a file that is secure deleted, should not be undeletable. Would this be something that people would be interested in doing? >>> New function ext4_secure_delete_lblks added to walk >>> data blocks and secure delete them before any blocks >>> are removed. >>> >>> Meta blocks are secure deleted before they are >>> released >>> >>> New function added to identify holes in ind files. >>> Used by ext4_secure_delete_lblks to skip over holes >>> during secure delete. >>> >>> Added another list in the journal structure to track >>> journal blocks so that they can be secure deleted later. >>> >>> Added new ext4_secure_delete_jblks that secure deletes >>> journal blocks that were used to journal the specified >>> logical blocks >>> >>> Allison Henderson (7): >>> ext4: Secure Delete: Add new EXT4_SECRM_RANDOM_FL flag >>> ext4: Secure Delete: Add ext4_ind_hole_lookup function >>> ext4: Secure Delete: Add secure delete functions >>> ext4: Secure Delete: Secure delete file data >>> ext4: Secure Delete: Secure delete directory entry >>> ext4: Secure Delete: Secure delete meta data blocks >>> ext4/jbd2: Secure Delete: Secure delete journal blocks >>> >>> fs/ext4/ext4.h | 28 +++- >>> fs/ext4/ext4_extents.h | 2 + >>> fs/ext4/extents.c | 21 +++- >>> fs/ext4/indirect.c | 2 +- >>> fs/ext4/inode.c | 391 ++++++++++++++++++++++++++++++++++++++++++++++++ >>> fs/ext4/mballoc.c | 8 + >>> fs/ext4/namei.c | 64 +++++++- >>> fs/jbd2/commit.c | 6 + >>> fs/jbd2/journal.c | 112 ++++++++++++++ >>> include/linux/jbd2.h | 21 +++ >>> 10 files changed, 642 insertions(+), 13 deletions(-) >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >>> the body of a message to majordomo@...r.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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