Re: svn commit: r367038 - head/sbin/mount_nullfs
In message <20201025213509.GA1671@brick>, Edward Tomasz Napierala writes: > On 1025T0717, Cy Schubert wrote: > > In message c > > om> > > , Oliver Pinter writes: > > > On Sunday, October 25, 2020, Edward Tomasz Napierala > > > wrote: > > > > > > > Author: trasz > > > > Date: Sun Oct 25 14:09:00 2020 > > > > New Revision: 367038 > > > > URL: https://svnweb.freebsd.org/changeset/base/367038 > > > > > > > > Log: > > > > Remove the check that prevents creating "loops" from mount_nullfs(8). > > > > > > > > > > > The simple question is: why? > > > > I was about to ask that myself. > > > > The why is usually more important than the how. > > Two reasons. > > First, from what I can tell this is an artificial limitation which serves > no purpose. I thought it was to prevent some kind of deadlock between > vnodes, so I asked kib@, and he mentioned removing that very limitation > from the kernel code; thus, it looks to me like a historical leftover. > > Second, I've stumbled upon this when trying to nullfs-mount '/' on > '/compat/ubuntu/bsd/', which would be useful for autochroot functionality, > when (or if) it becomes a thing. Thanks. -- Cheers, Cy Schubert FreeBSD UNIX: Web: https://FreeBSD.org NTP: Web: https://nwtime.org The need of the many outweighs the greed of the few. ___ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
Re: svn commit: r367038 - head/sbin/mount_nullfs
On Sunday, October 25, 2020, Edward Tomasz Napierala wrote: > On 1025T0717, Cy Schubert wrote: > > In message gmail.c > > om> > > , Oliver Pinter writes: > > > On Sunday, October 25, 2020, Edward Tomasz Napierala < > tr...@freebsd.org> > > > wrote: > > > > > > > Author: trasz > > > > Date: Sun Oct 25 14:09:00 2020 > > > > New Revision: 367038 > > > > URL: https://svnweb.freebsd.org/changeset/base/367038 > > > > > > > > Log: > > > > Remove the check that prevents creating "loops" from > mount_nullfs(8). > > > > > > > > > > > The simple question is: why? > > > > I was about to ask that myself. > > > > The why is usually more important than the how. > > Two reasons. > > First, from what I can tell this is an artificial limitation which serves > no purpose. I thought it was to prevent some kind of deadlock between > vnodes, so I asked kib@, and he mentioned removing that very limitation > from the kernel code; thus, it looks to me like a historical leftover. > > Second, I've stumbled upon this when trying to nullfs-mount '/' on > '/compat/ubuntu/bsd/', which would be useful for autochroot functionality, > when (or if) it becomes a thing. Thank you! ___ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
Re: svn commit: r367038 - head/sbin/mount_nullfs
On 1025T0717, Cy Schubert wrote: > In message om> > , Oliver Pinter writes: > > On Sunday, October 25, 2020, Edward Tomasz Napierala > > wrote: > > > > > Author: trasz > > > Date: Sun Oct 25 14:09:00 2020 > > > New Revision: 367038 > > > URL: https://svnweb.freebsd.org/changeset/base/367038 > > > > > > Log: > > > Remove the check that prevents creating "loops" from mount_nullfs(8). > > > > > > > > The simple question is: why? > > I was about to ask that myself. > > The why is usually more important than the how. Two reasons. First, from what I can tell this is an artificial limitation which serves no purpose. I thought it was to prevent some kind of deadlock between vnodes, so I asked kib@, and he mentioned removing that very limitation from the kernel code; thus, it looks to me like a historical leftover. Second, I've stumbled upon this when trying to nullfs-mount '/' on '/compat/ubuntu/bsd/', which would be useful for autochroot functionality, when (or if) it becomes a thing. ___ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
Re: svn commit: r367038 - head/sbin/mount_nullfs
In message , Oliver Pinter writes: > On Sunday, October 25, 2020, Edward Tomasz Napierala > wrote: > > > Author: trasz > > Date: Sun Oct 25 14:09:00 2020 > > New Revision: 367038 > > URL: https://svnweb.freebsd.org/changeset/base/367038 > > > > Log: > > Remove the check that prevents creating "loops" from mount_nullfs(8). > > > > > The simple question is: why? I was about to ask that myself. The why is usually more important than the how. -- Cheers, Cy Schubert FreeBSD UNIX: Web: https://FreeBSD.org NTP: Web: https://nwtime.org The need of the many outweighs the greed of the few. ___ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
Re: svn commit: r367038 - head/sbin/mount_nullfs
On Sunday, October 25, 2020, Edward Tomasz Napierala
wrote:
> Author: trasz
> Date: Sun Oct 25 14:09:00 2020
> New Revision: 367038
> URL: https://svnweb.freebsd.org/changeset/base/367038
>
> Log:
> Remove the check that prevents creating "loops" from mount_nullfs(8).
>
>
The simple question is: why?
> Reviewed by: kib
> MFC after:2 weeks
> Sponsored by: The FreeBSD Foundation
> Differential Revision:https://reviews.freebsd.org/D26921
>
> Modified:
> head/sbin/mount_nullfs/mount_nullfs.c
>
> Modified: head/sbin/mount_nullfs/mount_nullfs.c
>
> ==
> --- head/sbin/mount_nullfs/mount_nullfs.c Sun Oct 25 10:08:46 2020
> (r367037)
> +++ head/sbin/mount_nullfs/mount_nullfs.c Sun Oct 25 14:09:00 2020
> (r367038)
> @@ -59,7 +59,6 @@ static const char rcsid[] =
>
> #include "mntopts.h"
>
> -intsubdir(const char *, const char *);
> static voidusage(void) __dead2;
>
> int
> @@ -104,10 +103,6 @@ main(int argc, char *argv[])
> if (checkpath(argv[1], source) != 0)
> err(EX_USAGE, "%s", source);
>
> - if (subdir(target, source) || subdir(source, target))
> - errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
> - argv[0], target, argv[1]);
> -
> build_iovec(, , "fstype", nullfs, (size_t)-1);
> build_iovec(, , "fspath", source, (size_t)-1);
> build_iovec(, , "target", target, (size_t)-1);
> @@ -119,21 +114,6 @@ main(int argc, char *argv[])
> err(1, "%s", source);
> }
> exit(0);
> -}
> -
> -int
> -subdir(const char *p, const char *dir)
> -{
> - int l;
> -
> - l = strlen(dir);
> - if (l <= 1)
> - return (1);
> -
> - if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
> - return (1);
> -
> - return (0);
> }
>
> static void
> ___
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svn commit: r367038 - head/sbin/mount_nullfs
Author: trasz
Date: Sun Oct 25 14:09:00 2020
New Revision: 367038
URL: https://svnweb.freebsd.org/changeset/base/367038
Log:
Remove the check that prevents creating "loops" from mount_nullfs(8).
Reviewed by: kib
MFC after:2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision:https://reviews.freebsd.org/D26921
Modified:
head/sbin/mount_nullfs/mount_nullfs.c
Modified: head/sbin/mount_nullfs/mount_nullfs.c
==
--- head/sbin/mount_nullfs/mount_nullfs.c Sun Oct 25 10:08:46 2020
(r367037)
+++ head/sbin/mount_nullfs/mount_nullfs.c Sun Oct 25 14:09:00 2020
(r367038)
@@ -59,7 +59,6 @@ static const char rcsid[] =
#include "mntopts.h"
-intsubdir(const char *, const char *);
static voidusage(void) __dead2;
int
@@ -104,10 +103,6 @@ main(int argc, char *argv[])
if (checkpath(argv[1], source) != 0)
err(EX_USAGE, "%s", source);
- if (subdir(target, source) || subdir(source, target))
- errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
- argv[0], target, argv[1]);
-
build_iovec(, , "fstype", nullfs, (size_t)-1);
build_iovec(, , "fspath", source, (size_t)-1);
build_iovec(, , "target", target, (size_t)-1);
@@ -119,21 +114,6 @@ main(int argc, char *argv[])
err(1, "%s", source);
}
exit(0);
-}
-
-int
-subdir(const char *p, const char *dir)
-{
- int l;
-
- l = strlen(dir);
- if (l <= 1)
- return (1);
-
- if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
- return (1);
-
- return (0);
}
static void
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