Date: Fri, 8 Oct 2010 12:32:38 +0200 From: Ulrich =?utf-8?B?U3DDtnJsZWlu?= <uqs@spoerlein.net> To: Ivan Voras <ivoras@FreeBSD.org> Cc: Alexander Best <arundel@FreeBSD.org>, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, Pawel Jakub Dawidek <pjd@FreeBSD.org> Subject: Re: svn commit: r213398 - head/bin/rm Message-ID: <20101008103238.GV65440@acme.spoerlein.net> In-Reply-To: <AANLkTinoY232bRsut7swz3h-uJ5nXURgG7Tqhn7wGho7@mail.gmail.com> References: <201010040617.o946HkOO002409@svn.freebsd.org> <20101004092559.GB7322@garage.freebsd.pl> <20101004095845.GA99361@freebsd.org> <alpine.BSF.2.00.1010041435200.95088@woozle.rinet.ru> <20101004104257.GH7322@garage.freebsd.pl> <20101004114248.GA16641@freebsd.org> <AANLkTinoY232bRsut7swz3h-uJ5nXURgG7Tqhn7wGho7@mail.gmail.com>
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[-- Attachment #1 --]
On Mon, 04.10.2010 at 14:04:53 +0200, Ivan Voras wrote:
> On 4 October 2010 13:42, Alexander Best <arundel@freebsd.org> wrote:
>
> > good point. ZFS should really be added to the list and LFS should go away. are
> > there any other relevant filesystems without a fixed-block size that need to be
> > mentioned? what about afs? or tmpfs?
>
> (it's not that the block sizes aren't fixed, it's that the assignment
> of blocks to the file is not fixed).
Review of attached patch, anyone? I didn't come up with a clever way to
describe non-COW file systems :/
[-- Attachment #2 --]
commit 1756b0548e6b18a88e58fad0d078a507c2d87422
Author: Ulrich Spörlein <uqs@spoerlein.net>
Date: Fri Oct 8 12:29:06 2010 +0200
rm(1): clarify that -P works only when the block allocation is static
Suggested by: pjd, ivoras
diff --git a/bin/rm/rm.1 b/bin/rm/rm.1
index f580d33..dfba07b 100644
--- a/bin/rm/rm.1
+++ b/bin/rm/rm.1
@@ -32,7 +32,7 @@
.\" @(#)rm.1 8.5 (Berkeley) 12/5/94
.\" $FreeBSD$
.\"
-.Dd October 3, 2010
+.Dd October 8, 2010
.Dt RM 1
.Os
.Sh NAME
@@ -229,8 +229,8 @@ command appeared in
.Sh BUGS
The
.Fl P
-option assumes that the underlying file system is a fixed-block file
-system.
-UFS is a fixed-block file system, LFS is not.
+option assumes that the underlying file system does not allocate new blocks
+when writing to existing blocks.
+This is true for UFS but not for ZFS, which is using Copy-On-Write.
In addition, only regular files are overwritten, other types of files
are not.
diff --git a/bin/rm/rm.c b/bin/rm/rm.c
index d9bd296..653833a 100644
--- a/bin/rm/rm.c
+++ b/bin/rm/rm.c
@@ -402,8 +402,8 @@ rm_file(char **argv)
* This is a cheap way to *really* delete files. Note that only regular
* files are deleted, directories (and therefore names) will remain.
* Also, this assumes a fixed-block file system (like FFS, or a V7 or a
- * System V file system). In a logging file system, you'll have to have
- * kernel support.
+ * System V file system). In a logging or COW file system, you'll have to
+ * have kernel support.
*/
int
rm_overwrite(char *file, struct stat *sbp)
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