* [patch 0/2] r/o bind mount fixes for 2.6.23-mm1
@ 2007-10-12 15:50 Jan Blunck
2007-10-12 15:50 ` [patch 1/2] r/o bind mounts: Dont touch the vfsmount after path_put() Jan Blunck
2007-10-12 15:50 ` [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write() Jan Blunck
0 siblings, 2 replies; 6+ messages in thread
From: Jan Blunck @ 2007-10-12 15:50 UTC (permalink / raw)
To: Dave Hansen; +Cc: Linux-Kernel Mailinglist, Andrew Morton
Here are two small patches for 2.6.23-mm1 that fix some issues with the r/o
bind mount code. Besides that, I can see that you handle files opened by
dentry_open() somewhere. Nevertheless this files are also fput'ed later.
Regards,
Jan
--
^ permalink raw reply [flat|nested] 6+ messages in thread
* [patch 1/2] r/o bind mounts: Dont touch the vfsmount after path_put()
2007-10-12 15:50 [patch 0/2] r/o bind mount fixes for 2.6.23-mm1 Jan Blunck
@ 2007-10-12 15:50 ` Jan Blunck
2007-10-12 16:06 ` Dave Hansen
2007-10-12 15:50 ` [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write() Jan Blunck
1 sibling, 1 reply; 6+ messages in thread
From: Jan Blunck @ 2007-10-12 15:50 UTC (permalink / raw)
To: Dave Hansen; +Cc: Linux-Kernel Mailinglist, Andrew Morton
[-- Attachment #1: vfs/r-o-af_unix-bind-mnt_drop_write-fix.diff --]
[-- Type: text/plain, Size: 630 bytes --]
mnt_drop_write() is called after releasing the reference to the path with
path_put().
Signed-off-by: Jan Blunck <jblunck@suse.de>
---
net/unix/af_unix.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: b/net/unix/af_unix.c
===================================================================
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -752,8 +752,8 @@ static struct sock *unix_find_other(stru
if (u->sk_type == type)
touch_atime(nd.path.mnt, nd.path.dentry);
- path_put(&nd.path);
mnt_drop_write(nd.path.mnt);
+ path_put(&nd.path);
err=-EPROTOTYPE;
if (u->sk_type != type) {
--
^ permalink raw reply [flat|nested] 6+ messages in thread* [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write()
2007-10-12 15:50 [patch 0/2] r/o bind mount fixes for 2.6.23-mm1 Jan Blunck
2007-10-12 15:50 ` [patch 1/2] r/o bind mounts: Dont touch the vfsmount after path_put() Jan Blunck
@ 2007-10-12 15:50 ` Jan Blunck
2007-10-12 16:10 ` Dave Hansen
2007-10-13 11:25 ` Christoph Hellwig
1 sibling, 2 replies; 6+ messages in thread
From: Jan Blunck @ 2007-10-12 15:50 UTC (permalink / raw)
To: Dave Hansen; +Cc: Linux-Kernel Mailinglist, Andrew Morton
[-- Attachment #1: vfs/r-o-bind-mnt_drop_write-mnt-NULL-fix.diff --]
[-- Type: text/plain, Size: 613 bytes --]
In case of somebody opens a file with dentry_open(dentry, NULL, ...) we don't
want to stumble on the NULL pointer mnt in struct file.
Signed-off-by: Jan Blunck <jblunck@suse.de>
---
fs/namespace.c | 3 +++
1 file changed, 3 insertions(+)
Index: b/fs/namespace.c
===================================================================
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -253,6 +253,9 @@ void mnt_drop_write(struct vfsmount *mnt
int must_check_underflow = 0;
struct mnt_writer *cpu_writer;
+ if (!mnt)
+ return;
+
cpu_writer = &get_cpu_var(mnt_writers);
spin_lock(&cpu_writer->lock);
--
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write()
2007-10-12 15:50 ` [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write() Jan Blunck
@ 2007-10-12 16:10 ` Dave Hansen
2007-10-13 11:25 ` Christoph Hellwig
1 sibling, 0 replies; 6+ messages in thread
From: Dave Hansen @ 2007-10-12 16:10 UTC (permalink / raw)
To: Jan Blunck; +Cc: Linux-Kernel Mailinglist, Andrew Morton, Christoph Hellwig
On Fri, 2007-10-12 at 17:50 +0200, Jan Blunck wrote:
> In case of somebody opens a file with dentry_open(dentry, NULL, ...) we don't
> want to stumble on the NULL pointer mnt in struct file.
...
> +++ b/fs/namespace.c
> @@ -253,6 +253,9 @@ void mnt_drop_write(struct vfsmount *mnt
> int must_check_underflow = 0;
> struct mnt_writer *cpu_writer;
>
> + if (!mnt)
> + return;
I kinda wish we'd fix these in the callers. I know we do something
similar to this with mntput(), but I worry a bit that this just
discourages people from using the right interfaces.
Do you have a case where we're actually getting a NULL mount in here?
We had at least one in reiser4 that really revealed some nastiness in
the fs that needed fixing.
-- Dave
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write()
2007-10-12 15:50 ` [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write() Jan Blunck
2007-10-12 16:10 ` Dave Hansen
@ 2007-10-13 11:25 ` Christoph Hellwig
1 sibling, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2007-10-13 11:25 UTC (permalink / raw)
To: Jan Blunck; +Cc: Dave Hansen, Linux-Kernel Mailinglist, Andrew Morton
On Fri, Oct 12, 2007 at 05:50:21PM +0200, Jan Blunck wrote:
> In case of somebody opens a file with dentry_open(dentry, NULL, ...) we don't
> want to stumble on the NULL pointer mnt in struct file.
We should just not allow a NULL vfsmount in dentry_open. Dave and I have
fixes for reiserfs, and I'll look at the uml use.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2007-10-13 12:40 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-10-12 15:50 [patch 0/2] r/o bind mount fixes for 2.6.23-mm1 Jan Blunck
2007-10-12 15:50 ` [patch 1/2] r/o bind mounts: Dont touch the vfsmount after path_put() Jan Blunck
2007-10-12 16:06 ` Dave Hansen
2007-10-12 15:50 ` [patch 2/2] r/o bind mounts: Accept passing a mnt NULL pointer to mnt_drop_write() Jan Blunck
2007-10-12 16:10 ` Dave Hansen
2007-10-13 11:25 ` Christoph Hellwig
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