Re: svn commit: r214431 - head/bin/rm

2010-10-29 Thread Robert Watson
On Fri, 29 Oct 2010, Bruce Cran wrote: On Thu, 28 Oct 2010 14:11:14 -0700 Garrett Cooper wrote: Unfortunately it's implied superficially by the 3 pass tort; but as most people who understand magnetic disks know, unless you completely obliterate a disk, wipe over it with random data enough t

Re: svn commit: r214431 - head/bin/rm

2010-10-29 Thread Bruce Cran
On Thu, 28 Oct 2010 14:11:14 -0700 Garrett Cooper wrote: > Unfortunately it's implied superficially by the 3 pass tort; but as > most people who understand magnetic disks know, unless you completely > obliterate a disk, wipe over it with random data enough times, > whatever, the content is still

Re: svn commit: r214431 - head/bin/rm

2010-10-29 Thread Alexander Leidinger
Quoting Garrett Cooper (from Thu, 28 Oct 2010 14:11:14 -0700): Unfortunately it's implied superficially by the 3 pass tort; but as most people who understand magnetic disks know, unless you completely obliterate a disk, wipe over it with random data enough times, whatever, the content is stil

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Robert Watson
On Thu, 28 Oct 2010, Alexander Best wrote: For example, you could imagine a pathconf() call that asks the file system if overwriting a file is likely to result in the data going away -- UFS could answer "yes" unless it's snapshotting the file system, and ZFS could simply answer "no". In Fre

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Alexander Best
On Thu Oct 28 10, Robert Watson wrote: > On Thu, 28 Oct 2010, Gary Jennejohn wrote: > > >>>The -P option assumes that the underlying storage overwrites file block > >>>when data is written on existing offset. Several factors including the > >>>file system and its backing store could defeat the

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Robert Watson
On Thu, 28 Oct 2010, Gary Jennejohn wrote: The -P option assumes that the underlying storage overwrites file block when data is written on existing offset. Several factors including the file system and its backing store could defeat the assumption, this includes, but is not limited to file sy

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Alexander Best
On Thu Oct 28 10, Ceri Davies wrote: > On Thu, Oct 28, 2010 at 10:25:47AM +, Alexander Best wrote: > > On Thu Oct 28 10, Gary Jennejohn wrote: > > > On Thu, 28 Oct 2010 16:22:05 +1100 (EST) > > > Bruce Evans wrote: > > > > > > > On Wed, 27 Oct 2010, Xin LI wrote: > > > > > > > > > I think wh

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Ceri Davies
On Thu, Oct 28, 2010 at 10:25:47AM +, Alexander Best wrote: > On Thu Oct 28 10, Gary Jennejohn wrote: > > On Thu, 28 Oct 2010 16:22:05 +1100 (EST) > > Bruce Evans wrote: > > > > > On Wed, 27 Oct 2010, Xin LI wrote: > > > > > > > I think what really defeats -P is the fact that the file system

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Alexander Best
On Thu Oct 28 10, Gary Jennejohn wrote: > On Thu, 28 Oct 2010 16:22:05 +1100 (EST) > Bruce Evans wrote: > > > On Wed, 27 Oct 2010, Xin LI wrote: > > > > > I think what really defeats -P is the fact that the file system or > > > underlying data storage would not overwrite data on a file at sync()

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Ceri Davies
On Thu, Oct 28, 2010 at 09:55:38AM +0200, Gary Jennejohn wrote: > On Thu, 28 Oct 2010 16:22:05 +1100 (EST) > Bruce Evans wrote: > > > On Wed, 27 Oct 2010, Xin LI wrote: > > > > > I think what really defeats -P is the fact that the file system or > > > underlying data storage would not overwrite

Re: svn commit: r214431 - head/bin/rm

2010-10-28 Thread Gary Jennejohn
On Thu, 28 Oct 2010 16:22:05 +1100 (EST) Bruce Evans wrote: > On Wed, 27 Oct 2010, Xin LI wrote: > > > I think what really defeats -P is the fact that the file system or > > underlying data storage would not overwrite data on a file at sync(). > > COW is of course one of the case, journaling MAY

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Bruce Evans
On Wed, 27 Oct 2010, Xin LI wrote: I think what really defeats -P is the fact that the file system or underlying data storage would not overwrite data on a file at sync(). COW is of course one of the case, journaling MAY defeat -P but is not guaranteed. FS with variable block size - I believe t

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Alexey Dokuchaev
On Wed, Oct 27, 2010 at 03:33:01PM -0700, Xin LI wrote: > Maybe something like: > > BUGS > > The -P option assumes that the underlying storage overwrites file block > when data is written on existing offset. Several factors including the > file system and its backing store could defeat the assum

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Alexander Best
On Wed Oct 27 10, Xin LI wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA256 > > On 10/27/10 14:48, Alexander Best wrote: > > On Wed Oct 27 10, Doug Barton wrote: > >> On 10/27/10 14:26, Alexander Best wrote: > >>> are in fact COW fs the only exception where the -P flag won't work? before >

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Alexander Best
On Wed Oct 27 10, Juli Mallett wrote: > On Wed, Oct 27, 2010 at 14:48, Alexander Best wrote: > > On Wed Oct 27 10, Doug Barton wrote: > >> What may be a better approach is to confirm the fs' that DO work, list > >> them, and then add something to the effect of, "This feature is unlikely > >> to wo

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Xin LI
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 On 10/27/10 14:48, Alexander Best wrote: > On Wed Oct 27 10, Doug Barton wrote: >> On 10/27/10 14:26, Alexander Best wrote: >>> are in fact COW fs the only exception where the -P flag won't work? before >>> r213582 LFS was mentioned here and that the

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Juli Mallett
On Wed, Oct 27, 2010 at 14:48, Alexander Best wrote: > On Wed Oct 27 10, Doug Barton wrote: >> What may be a better approach is to confirm the fs' that DO work, list >> them, and then add something to the effect of, "This feature is unlikely >> to work on other file systems." > > i don't think tha

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Alexander Best
On Wed Oct 27 10, Doug Barton wrote: > On 10/27/10 14:26, Alexander Best wrote: > >are in fact COW fs the only exception where the -P flag won't work? before > >r213582 LFS was mentioned here and that the block size must be fixed. > >also the comment in rm.c says that -P won't work for any logging

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Doug Barton
On 10/27/10 14:26, Alexander Best wrote: are in fact COW fs the only exception where the -P flag won't work? before r213582 LFS was mentioned here and that the block size must be fixed. also the comment in rm.c says that -P won't work for any logging file systems. i'm not a fs expert, but i think

Re: svn commit: r214431 - head/bin/rm

2010-10-27 Thread Alexander Best
On Wed Oct 27 10, Dag-Erling Smorgrav wrote: > Author: des > Date: Wed Oct 27 18:48:23 2010 > New Revision: 214431 > URL: http://svn.freebsd.org/changeset/base/214431 > > Log: > Language cleanup. > > Modified: > head/bin/rm/rm.1 > > Modified: head/bin/rm/rm.1 > ==

svn commit: r214431 - head/bin/rm

2010-10-27 Thread Dag-Erling Smorgrav
Author: des Date: Wed Oct 27 18:48:23 2010 New Revision: 214431 URL: http://svn.freebsd.org/changeset/base/214431 Log: Language cleanup. Modified: head/bin/rm/rm.1 Modified: head/bin/rm/rm.1 == --- head/bin/rm/rm.1