* [PATCH 1/1] VFS: fixes a bug in sys_linkat()
@ 2006-09-13 0:57 Ram Pai
2006-09-13 1:11 ` Al Viro
0 siblings, 1 reply; 3+ messages in thread
From: Ram Pai @ 2006-09-13 0:57 UTC (permalink / raw)
To: linux-kernel; +Cc: akpm, linuxram, nacc, viro
Hardlink using sys_linkat() returns EXDEV when the source and the destination
point to the same filesystem, residing under different mounts.
An example scenario is:
mount /dev/sda /mnt
mount /dev/sdb /mnt1
mkdir /mnt1/src
mkdir /mnt/dest
mount --bind /mnt1/src /mnt/dest (note: at this point the filesystems
under /mnt1/src and /mnt/dest is same)
touch /mnt1/src/testfile
ln /mnt1/src/testfile /mnt/dest/sametestfile (note: this should succeed).
The ln command fails. It does not correctly recognize that both
the source and destination point to the same filesystem.
The following patch fixes the problem.
Thanks to Nishanth Aravamudan(nacc@us.ibm.com) for identifying the bug.
Signed by Ram Pai (linuxram@us.ibm.com)
---
fs/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.17.10/fs/namei.c
===================================================================
--- linux-2.6.17.10.orig/fs/namei.c
+++ linux-2.6.17.10/fs/namei.c
@@ -2263,7 +2263,7 @@ asmlinkage long sys_linkat(int olddfd, c
if (error)
goto out;
error = -EXDEV;
- if (old_nd.mnt != nd.mnt)
+ if (old_nd.mnt->mnt_sb != nd.mnt->mnt_sb)
goto out_release;
new_dentry = lookup_create(&nd, 0);
error = PTR_ERR(new_dentry);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] VFS: fixes a bug in sys_linkat()
2006-09-13 0:57 [PATCH 1/1] VFS: fixes a bug in sys_linkat() Ram Pai
@ 2006-09-13 1:11 ` Al Viro
2006-09-13 1:32 ` Ram Pai
0 siblings, 1 reply; 3+ messages in thread
From: Al Viro @ 2006-09-13 1:11 UTC (permalink / raw)
To: Ram Pai; +Cc: linux-kernel, akpm, nacc
On Tue, Sep 12, 2006 at 05:57:38PM -0700, Ram Pai wrote:
> Hardlink using sys_linkat() returns EXDEV when the source and the destination
> point to the same filesystem, residing under different mounts.
... and that is absolutely deliberate. Ability to restrict links to
a subtree is a deliberate feature.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] VFS: fixes a bug in sys_linkat()
2006-09-13 1:11 ` Al Viro
@ 2006-09-13 1:32 ` Ram Pai
0 siblings, 0 replies; 3+ messages in thread
From: Ram Pai @ 2006-09-13 1:32 UTC (permalink / raw)
To: Al Viro; +Cc: linux-kernel, akpm, nacc
On Wed, 2006-09-13 at 02:11 +0100, Al Viro wrote:
> On Tue, Sep 12, 2006 at 05:57:38PM -0700, Ram Pai wrote:
> > Hardlink using sys_linkat() returns EXDEV when the source and the destination
> > point to the same filesystem, residing under different mounts.
>
> ... and that is absolutely deliberate. Ability to restrict links to
> a subtree is a deliberate feature.
But wondering what side effects will it have if we allowed it to create
hardlinks?
RP
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2006-09-13 1:32 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2006-09-13 0:57 [PATCH 1/1] VFS: fixes a bug in sys_linkat() Ram Pai
2006-09-13 1:11 ` Al Viro
2006-09-13 1:32 ` Ram Pai
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