Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 14:50 +0800, Ian Kent wrote:
> On Thu, 2016-10-27 at 10:47 +0800, Ian Kent wrote:
> > 
> > On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> > > 
> > >  
> > > 
> > > How much testing did it get?  I've several test setups involving
> > > autofs, but they are nowhere near exhaustive and I don't have good
> > > enough feel of the codebase to slap together something with decent
> > > coverage...
> > It got my standard testing.
> > 
> > For that I use a modified version of the autofs Connectathon system.
> > 
> > It's more about testing a wide variety of syntax and map setups and so
> > exercises
> > a large number of different types of autofs mounts.
> > 
> > It's meant to check normal operation but not so much stress testing even
> > though
> > it does perform quite a few mounts (around 250-300, not to mention the
> > autofs
> > mounts themselves).
> > 
> > I have another standard test I call the submount-test and it was originally
> > done
> > to stress test the most common problem I see, concurrent expire to mount.
> > 
> > I didn't see any problems I couldn't explain in these but I might need to
> > re-
> > visit the submount-test to see if it is still doing what I want.
> > 
> > OTOH, the pattern of mount and umount I see when the submount-test is run
> > does
> > look like it is doing what I want but it might not be getting all the way to
> > the
> > top of the tree of mounts enough times over the course of the test.
> > 
> > So I'm happy with my testing, just not as happy as I could be.
> Well, almost happy with my testing.
> 
> Naturally I also tested the specific case this series is meant to fix.
> 
> Basically:
> ls /mnt/foo# do the initial automount
> unshare -m sleep 10 &  # hold the automount in a new namespace
> umount /mnt/foo# pretend the mount timed out
> ls /mnt/foo# try to access it again
> ls: cannot open directory '/mnt/foo': Too many levels of symbolic links
> 
> as seen on the autofs mailing list. My specific test was a little different
> but
> verified this was resolved.
> 
> Now that Al seems reasonably OK with the series, with some changes, I'll test
> some other use cases, mainly to verify the expire still functions as required.
> That might need more work.

I have done some further tests, specifically for (what I believe are) the two
most common use cases.

First, using automount(8) entirely within a container, as expected works fine.

But the second case, one where automount(8) is run in the root namespace and has
automount directories bound into a container does have a problem.

The problem is due to may_umount_tree() only considering mounts in the root
namespace and leads to expire attempts on mounts even if they are in use in
another namespace.

It's not a serious problem as the umount attempt fails because the mount is busy
but it would be good to avoid the call back overhead.

Unfortunately it looks like transforming may_umount_tree() to use a similar
check to may_umount() introduces a race (picked up by my submount-test) which
I'm struggling to understand, I'll continue to work on it.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 14:50 +0800, Ian Kent wrote:
> On Thu, 2016-10-27 at 10:47 +0800, Ian Kent wrote:
> > 
> > On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> > > 
> > >  
> > > 
> > > How much testing did it get?  I've several test setups involving
> > > autofs, but they are nowhere near exhaustive and I don't have good
> > > enough feel of the codebase to slap together something with decent
> > > coverage...
> > It got my standard testing.
> > 
> > For that I use a modified version of the autofs Connectathon system.
> > 
> > It's more about testing a wide variety of syntax and map setups and so
> > exercises
> > a large number of different types of autofs mounts.
> > 
> > It's meant to check normal operation but not so much stress testing even
> > though
> > it does perform quite a few mounts (around 250-300, not to mention the
> > autofs
> > mounts themselves).
> > 
> > I have another standard test I call the submount-test and it was originally
> > done
> > to stress test the most common problem I see, concurrent expire to mount.
> > 
> > I didn't see any problems I couldn't explain in these but I might need to
> > re-
> > visit the submount-test to see if it is still doing what I want.
> > 
> > OTOH, the pattern of mount and umount I see when the submount-test is run
> > does
> > look like it is doing what I want but it might not be getting all the way to
> > the
> > top of the tree of mounts enough times over the course of the test.
> > 
> > So I'm happy with my testing, just not as happy as I could be.
> Well, almost happy with my testing.
> 
> Naturally I also tested the specific case this series is meant to fix.
> 
> Basically:
> ls /mnt/foo# do the initial automount
> unshare -m sleep 10 &  # hold the automount in a new namespace
> umount /mnt/foo# pretend the mount timed out
> ls /mnt/foo# try to access it again
> ls: cannot open directory '/mnt/foo': Too many levels of symbolic links
> 
> as seen on the autofs mailing list. My specific test was a little different
> but
> verified this was resolved.
> 
> Now that Al seems reasonably OK with the series, with some changes, I'll test
> some other use cases, mainly to verify the expire still functions as required.
> That might need more work.

I have done some further tests, specifically for (what I believe are) the two
most common use cases.

First, using automount(8) entirely within a container, as expected works fine.

But the second case, one where automount(8) is run in the root namespace and has
automount directories bound into a container does have a problem.

The problem is due to may_umount_tree() only considering mounts in the root
namespace and leads to expire attempts on mounts even if they are in use in
another namespace.

It's not a serious problem as the umount attempt fails because the mount is busy
but it would be good to avoid the call back overhead.

Unfortunately it looks like transforming may_umount_tree() to use a similar
check to may_umount() introduces a race (picked up by my submount-test) which
I'm struggling to understand, I'll continue to work on it.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 10:47 +0800, Ian Kent wrote:
> On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> > 
> > 
> > How much testing did it get?  I've several test setups involving
> > autofs, but they are nowhere near exhaustive and I don't have good
> > enough feel of the codebase to slap together something with decent
> > coverage...
> It got my standard testing.
> 
> For that I use a modified version of the autofs Connectathon system.
> 
> It's more about testing a wide variety of syntax and map setups and so
> exercises
> a large number of different types of autofs mounts.
> 
> It's meant to check normal operation but not so much stress testing even
> though
> it does perform quite a few mounts (around 250-300, not to mention the autofs
> mounts themselves).
> 
> I have another standard test I call the submount-test and it was originally
> done
> to stress test the most common problem I see, concurrent expire to mount.
> 
> I didn't see any problems I couldn't explain in these but I might need to re-
> visit the submount-test to see if it is still doing what I want.
> 
> OTOH, the pattern of mount and umount I see when the submount-test is run does
> look like it is doing what I want but it might not be getting all the way to
> the
> top of the tree of mounts enough times over the course of the test.
> 
> So I'm happy with my testing, just not as happy as I could be.

Well, almost happy with my testing.

Naturally I also tested the specific case this series is meant to fix.

Basically:
ls /mnt/foo# do the initial automount
unshare -m sleep 10 &  # hold the automount in a new namespace
umount /mnt/foo# pretend the mount timed out
ls /mnt/foo# try to access it again
ls: cannot open directory '/mnt/foo': Too many levels of symbolic links

as seen on the autofs mailing list. My specific test was a little different but
verified this was resolved.

Now that Al seems reasonably OK with the series, with some changes, I'll test
some other use cases, mainly to verify the expire still functions as required.
That might need more work.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 10:47 +0800, Ian Kent wrote:
> On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> > 
> > 
> > How much testing did it get?  I've several test setups involving
> > autofs, but they are nowhere near exhaustive and I don't have good
> > enough feel of the codebase to slap together something with decent
> > coverage...
> It got my standard testing.
> 
> For that I use a modified version of the autofs Connectathon system.
> 
> It's more about testing a wide variety of syntax and map setups and so
> exercises
> a large number of different types of autofs mounts.
> 
> It's meant to check normal operation but not so much stress testing even
> though
> it does perform quite a few mounts (around 250-300, not to mention the autofs
> mounts themselves).
> 
> I have another standard test I call the submount-test and it was originally
> done
> to stress test the most common problem I see, concurrent expire to mount.
> 
> I didn't see any problems I couldn't explain in these but I might need to re-
> visit the submount-test to see if it is still doing what I want.
> 
> OTOH, the pattern of mount and umount I see when the submount-test is run does
> look like it is doing what I want but it might not be getting all the way to
> the
> top of the tree of mounts enough times over the course of the test.
> 
> So I'm happy with my testing, just not as happy as I could be.

Well, almost happy with my testing.

Naturally I also tested the specific case this series is meant to fix.

Basically:
ls /mnt/foo# do the initial automount
unshare -m sleep 10 &  # hold the automount in a new namespace
umount /mnt/foo# pretend the mount timed out
ls /mnt/foo# try to access it again
ls: cannot open directory '/mnt/foo': Too many levels of symbolic links

as seen on the autofs mailing list. My specific test was a little different but
verified this was resolved.

Now that Al seems reasonably OK with the series, with some changes, I'll test
some other use cases, mainly to verify the expire still functions as required.
That might need more work.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> On Fri, Oct 21, 2016 at 07:39:36AM +0800, Ian Kent wrote:
> 
> > 
> > Maybe Al has been too busy to comment, he has been on the Cc from the start.
> That's... a very mild version of what's been going on.  Let's just say that
> the last few weeks had been really interesting.  Not that the shit has
> settled, but there was some slackening in the shitstorm last few days.
> Unlikely to last, I'm afraid, but...
>  
> > 
> > Hopefully this email will prompt a review, Al?
> Aside of the Eric's note re constifying struct path (strongly seconded),
> I'm not sure if expiration-related side of that is correct.  OTOH,
> since the expiration happens from userland...

Sure, I have a follow up series to do the constifying as recommended by Eric and
now yourself.

> 
> How much testing did it get?  I've several test setups involving
> autofs, but they are nowhere near exhaustive and I don't have good
> enough feel of the codebase to slap together something with decent
> coverage...

It got my standard testing.

For that I use a modified version of the autofs Connectathon system.

It's more about testing a wide variety of syntax and map setups and so exercises
a large number of different types of autofs mounts.

It's meant to check normal operation but not so much stress testing even though
it does perform quite a few mounts (around 250-300, not to mention the autofs
mounts themselves).

I have another standard test I call the submount-test and it was originally done
to stress test the most common problem I see, concurrent expire to mount.

I didn't see any problems I couldn't explain in these but I might need to re-
visit the submount-test to see if it is still doing what I want.

OTOH, the pattern of mount and umount I see when the submount-test is run does
look like it is doing what I want but it might not be getting all the way to the
top of the tree of mounts enough times over the course of the test.

So I'm happy with my testing, just not as happy as I could be.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Thu, 2016-10-27 at 03:11 +0100, Al Viro wrote:
> On Fri, Oct 21, 2016 at 07:39:36AM +0800, Ian Kent wrote:
> 
> > 
> > Maybe Al has been too busy to comment, he has been on the Cc from the start.
> That's... a very mild version of what's been going on.  Let's just say that
> the last few weeks had been really interesting.  Not that the shit has
> settled, but there was some slackening in the shitstorm last few days.
> Unlikely to last, I'm afraid, but...
>  
> > 
> > Hopefully this email will prompt a review, Al?
> Aside of the Eric's note re constifying struct path (strongly seconded),
> I'm not sure if expiration-related side of that is correct.  OTOH,
> since the expiration happens from userland...

Sure, I have a follow up series to do the constifying as recommended by Eric and
now yourself.

> 
> How much testing did it get?  I've several test setups involving
> autofs, but they are nowhere near exhaustive and I don't have good
> enough feel of the codebase to slap together something with decent
> coverage...

It got my standard testing.

For that I use a modified version of the autofs Connectathon system.

It's more about testing a wide variety of syntax and map setups and so exercises
a large number of different types of autofs mounts.

It's meant to check normal operation but not so much stress testing even though
it does perform quite a few mounts (around 250-300, not to mention the autofs
mounts themselves).

I have another standard test I call the submount-test and it was originally done
to stress test the most common problem I see, concurrent expire to mount.

I didn't see any problems I couldn't explain in these but I might need to re-
visit the submount-test to see if it is still doing what I want.

OTOH, the pattern of mount and umount I see when the submount-test is run does
look like it is doing what I want but it might not be getting all the way to the
top of the tree of mounts enough times over the course of the test.

So I'm happy with my testing, just not as happy as I could be.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Al Viro]

On Fri, Oct 21, 2016 at 07:39:36AM +0800, Ian Kent wrote:

> Maybe Al has been too busy to comment, he has been on the Cc from the start.

That's... a very mild version of what's been going on.  Let's just say that
the last few weeks had been really interesting.  Not that the shit has
settled, but there was some slackening in the shitstorm last few days.
Unlikely to last, I'm afraid, but...
 
> Hopefully this email will prompt a review, Al?

Aside of the Eric's note re constifying struct path (strongly seconded),
I'm not sure if expiration-related side of that is correct.  OTOH,
since the expiration happens from userland...

How much testing did it get?  I've several test setups involving
autofs, but they are nowhere near exhaustive and I don't have good
enough feel of the codebase to slap together something with decent
coverage...

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Al Viro]

On Fri, Oct 21, 2016 at 07:39:36AM +0800, Ian Kent wrote:

> Maybe Al has been too busy to comment, he has been on the Cc from the start.

That's... a very mild version of what's been going on.  Let's just say that
the last few weeks had been really interesting.  Not that the shit has
settled, but there was some slackening in the shitstorm last few days.
Unlikely to last, I'm afraid, but...
 
> Hopefully this email will prompt a review, Al?

Aside of the Eric's note re constifying struct path (strongly seconded),
I'm not sure if expiration-related side of that is correct.  OTOH,
since the expiration happens from userland...

How much testing did it get?  I've several test setups involving
autofs, but they are nowhere near exhaustive and I don't have good
enough feel of the codebase to slap together something with decent
coverage...

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Wed, 2016-10-19 at 12:40 -0700, Andrew Morton wrote:
> On Tue, 11 Oct 2016 13:33:52 +0800 Ian Kent  wrote:
> 
> > For the autofs module to be able to reliably check if a dentry is a
> > mountpoint in a multiple namespace environment the ->d_manage() dentry
> > operation will need to take a path argument instead of a dentry.
> 
> This patchset contains lots of ViroStuff.  I'll queue it up for some
> testing and will go into wait-and-see mode.

Thanks Andrew.

Maybe Al has been too busy to comment, he has been on the Cc from the start.

Hopefully this email will prompt a review, Al?

> 
> Some patches had an explicit From: Ian Kent  and some
> did not.  I assumed that this was intended for all patches.  So all
> patches now have different From: and Signed-off-by: email addresses. 
> Unclear if this was your intent ;)

Umm ... sorry about that, I didn't pay enough attention to the From of the
patches when I resurrected them from an earlier attempt at this.

Since the time I did this with an earlier patch series I have elected to not
change my git config and set these in the local tree config so it shouldn't
happen for new work. I'll pay special attention to this if I need to resurrect
any other older patches too.

I know this looks confusing and isn't the best but both email addresses have
been present on my gpg key for a long time so it's verifiable the patches are
from me.

Once again sorry about that.
Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Wed, 2016-10-19 at 12:40 -0700, Andrew Morton wrote:
> On Tue, 11 Oct 2016 13:33:52 +0800 Ian Kent  wrote:
> 
> > For the autofs module to be able to reliably check if a dentry is a
> > mountpoint in a multiple namespace environment the ->d_manage() dentry
> > operation will need to take a path argument instead of a dentry.
> 
> This patchset contains lots of ViroStuff.  I'll queue it up for some
> testing and will go into wait-and-see mode.

Thanks Andrew.

Maybe Al has been too busy to comment, he has been on the Cc from the start.

Hopefully this email will prompt a review, Al?

> 
> Some patches had an explicit From: Ian Kent  and some
> did not.  I assumed that this was intended for all patches.  So all
> patches now have different From: and Signed-off-by: email addresses. 
> Unclear if this was your intent ;)

Umm ... sorry about that, I didn't pay enough attention to the From of the
patches when I resurrected them from an earlier attempt at this.

Since the time I did this with an earlier patch series I have elected to not
change my git config and set these in the local tree config so it shouldn't
happen for new work. I'll pay special attention to this if I need to resurrect
any other older patches too.

I know this looks confusing and isn't the best but both email addresses have
been present on my gpg key for a long time so it's verifiable the patches are
from me.

Once again sorry about that.
Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Andrew Morton]

On Tue, 11 Oct 2016 13:33:52 +0800 Ian Kent  wrote:

> For the autofs module to be able to reliably check if a dentry is a
> mountpoint in a multiple namespace environment the ->d_manage() dentry
> operation will need to take a path argument instead of a dentry.

This patchset contains lots of ViroStuff.  I'll queue it up for some
testing and will go into wait-and-see mode.

Some patches had an explicit From: Ian Kent  and some
did not.  I assumed that this was intended for all patches.  So all
patches now have different From: and Signed-off-by: email addresses. 
Unclear if this was your intent ;)

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Andrew Morton]

On Tue, 11 Oct 2016 13:33:52 +0800 Ian Kent  wrote:

> For the autofs module to be able to reliably check if a dentry is a
> mountpoint in a multiple namespace environment the ->d_manage() dentry
> operation will need to take a path argument instead of a dentry.

This patchset contains lots of ViroStuff.  I'll queue it up for some
testing and will go into wait-and-see mode.

Some patches had an explicit From: Ian Kent  and some
did not.  I assumed that this was intended for all patches.  So all
patches now have different From: and Signed-off-by: email addresses. 
Unclear if this was your intent ;)

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Tue, 2016-10-11 at 11:04 -0500, Eric W. Biederman wrote:
> Ian Kent  writes:
> 
> > For the autofs module to be able to reliably check if a dentry is a
> > mountpoint in a multiple namespace environment the ->d_manage() dentry
> > operation will need to take a path argument instead of a dentry.
> 
> Taking a quick look overall I see no issues with this series.  Overall
> it seems straight forward.
> 
> On the nit side I expect saying const struct path * in the functions
> that now take a struct path would be useful.
> 
> I suspect it would also be useful to say
>   const struct path *path;
> path = >f_path;
> 
> In the one part of the code where you do that.  Instead of copying the
> path out of the struct file.
> 
> Overall I expect that will keep down bugs at no reduction in usability.
> Just a statement that the struct path won't change when it is passed
> to various functions.

Thanks Eric, that's a good suggestion for a follow up patch, will do.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

On Tue, 2016-10-11 at 11:04 -0500, Eric W. Biederman wrote:
> Ian Kent  writes:
> 
> > For the autofs module to be able to reliably check if a dentry is a
> > mountpoint in a multiple namespace environment the ->d_manage() dentry
> > operation will need to take a path argument instead of a dentry.
> 
> Taking a quick look overall I see no issues with this series.  Overall
> it seems straight forward.
> 
> On the nit side I expect saying const struct path * in the functions
> that now take a struct path would be useful.
> 
> I suspect it would also be useful to say
>   const struct path *path;
> path = >f_path;
> 
> In the one part of the code where you do that.  Instead of copying the
> path out of the struct file.
> 
> Overall I expect that will keep down bugs at no reduction in usability.
> Just a statement that the struct path won't change when it is passed
> to various functions.

Thanks Eric, that's a good suggestion for a follow up patch, will do.

Ian

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Eric W. Biederman]

Ian Kent  writes:

> For the autofs module to be able to reliably check if a dentry is a
> mountpoint in a multiple namespace environment the ->d_manage() dentry
> operation will need to take a path argument instead of a dentry.

Taking a quick look overall I see no issues with this series.  Overall
it seems straight forward.

On the nit side I expect saying const struct path * in the functions
that now take a struct path would be useful.

I suspect it would also be useful to say
const struct path *path;
path = >f_path;

In the one part of the code where you do that.  Instead of copying the
path out of the struct file.

Overall I expect that will keep down bugs at no reduction in usability.
Just a statement that the struct path won't change when it is passed
to various functions.

Eric

Re: [PATCH 1/8] vfs - change d_manage() to take a struct path

[Eric W. Biederman]

Ian Kent  writes:

> For the autofs module to be able to reliably check if a dentry is a
> mountpoint in a multiple namespace environment the ->d_manage() dentry
> operation will need to take a path argument instead of a dentry.

Taking a quick look overall I see no issues with this series.  Overall
it seems straight forward.

On the nit side I expect saying const struct path * in the functions
that now take a struct path would be useful.

I suspect it would also be useful to say
const struct path *path;
path = >f_path;

In the one part of the code where you do that.  Instead of copying the
path out of the struct file.

Overall I expect that will keep down bugs at no reduction in usability.
Just a statement that the struct path won't change when it is passed
to various functions.

Eric

[PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Eric W. Biederman 
Cc: Omar Sandoval 
---
 Documentation/filesystems/Locking |2 +-
 Documentation/filesystems/vfs.txt |2 +-
 fs/autofs4/root.c |5 +++--
 fs/namei.c|   13 ++---
 include/linux/dcache.h|2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/Locking 
b/Documentation/filesystems/Locking
index fe15682..1949ac4 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 
diff --git a/Documentation/filesystems/vfs.txt 
b/Documentation/filesystems/vfs.txt
index bc3b8e0..db70d71 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -934,7 +934,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 };
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index a11f731..5cbd4e1 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file 
*file);
 static struct dentry *autofs4_lookup(struct inode *,
 struct dentry *, unsigned int);
 static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(struct path *, bool);
 static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
@@ -421,8 +421,9 @@ static struct vfsmount *autofs4_d_automount(struct path 
*path)
return NULL;
 }
 
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(struct path *path, bool rcu_walk)
 {
+   struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
diff --git a/fs/namei.c b/fs/namei.c
index a7f601c..704766a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct 
nameidata *nd)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
break;
}
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
 }
 EXPORT_SYMBOL(follow_down_one);
 
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(struct path *path)
 {
-   return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
-   dentry->d_op->d_manage(dentry, true) : 0;
+   return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+   path->dentry->d_op->d_manage(path, true) : 0;
 }
 
 /*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, 
struct path *path,
 * Don't forget we might have a non-mountpoint managed dentry
 * that wants to block transit.
 */
-   switch (managed_dentry_rcu(path->dentry)) {
+   switch (managed_dentry_rcu(path)) {
case -ECHILD:
default:
return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(
-   path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)

[PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Eric W. Biederman 
Cc: Omar Sandoval 
---
 Documentation/filesystems/Locking |2 +-
 Documentation/filesystems/vfs.txt |2 +-
 fs/autofs4/root.c |5 +++--
 fs/namei.c|   13 ++---
 include/linux/dcache.h|2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/Locking 
b/Documentation/filesystems/Locking
index fe15682..1949ac4 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 
diff --git a/Documentation/filesystems/vfs.txt 
b/Documentation/filesystems/vfs.txt
index bc3b8e0..db70d71 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -934,7 +934,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 };
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index a11f731..5cbd4e1 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file 
*file);
 static struct dentry *autofs4_lookup(struct inode *,
 struct dentry *, unsigned int);
 static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(struct path *, bool);
 static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
@@ -421,8 +421,9 @@ static struct vfsmount *autofs4_d_automount(struct path 
*path)
return NULL;
 }
 
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(struct path *path, bool rcu_walk)
 {
+   struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
diff --git a/fs/namei.c b/fs/namei.c
index a7f601c..704766a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct 
nameidata *nd)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
break;
}
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
 }
 EXPORT_SYMBOL(follow_down_one);
 
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(struct path *path)
 {
-   return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
-   dentry->d_op->d_manage(dentry, true) : 0;
+   return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+   path->dentry->d_op->d_manage(path, true) : 0;
 }
 
 /*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, 
struct path *path,
 * Don't forget we might have a non-mountpoint managed dentry
 * that wants to block transit.
 */
-   switch (managed_dentry_rcu(path->dentry)) {
+   switch (managed_dentry_rcu(path)) {
case -ECHILD:
default:
return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(
-   path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
diff --git a/include/linux/dcache.h 

[RFC PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Eric W. Biederman 
Cc: Omar Sandoval 
---
 Documentation/filesystems/Locking |2 +-
 Documentation/filesystems/vfs.txt |2 +-
 fs/autofs4/root.c |5 +++--
 fs/namei.c|   13 ++---
 include/linux/dcache.h|2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/Locking 
b/Documentation/filesystems/Locking
index d30fb2c..189ea98 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 
diff --git a/Documentation/filesystems/vfs.txt 
b/Documentation/filesystems/vfs.txt
index 9ace359..0035ac8 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -939,7 +939,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 };
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index fa84bb8..0705daa 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file 
*file);
 static struct dentry *autofs4_lookup(struct inode *,
 struct dentry *, unsigned int);
 static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(struct path *, bool);
 static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
@@ -421,8 +421,9 @@ done:
return NULL;
 }
 
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(struct path *path, bool rcu_walk)
 {
+   struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
diff --git a/fs/namei.c b/fs/namei.c
index adb0414..e86b9d0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct 
nameidata *nd)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
break;
}
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
 }
 EXPORT_SYMBOL(follow_down_one);
 
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(struct path *path)
 {
-   return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
-   dentry->d_op->d_manage(dentry, true) : 0;
+   return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+   path->dentry->d_op->d_manage(path, true) : 0;
 }
 
 /*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, 
struct path *path,
 * Don't forget we might have a non-mountpoint managed dentry
 * that wants to block transit.
 */
-   switch (managed_dentry_rcu(path->dentry)) {
+   switch (managed_dentry_rcu(path)) {
case -ECHILD:
default:
return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(
-   path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
diff 

[RFC PATCH 1/8] vfs - change d_manage() to take a struct path

[Ian Kent]

For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Eric W. Biederman 
Cc: Omar Sandoval 
---
 Documentation/filesystems/Locking |2 +-
 Documentation/filesystems/vfs.txt |2 +-
 fs/autofs4/root.c |5 +++--
 fs/namei.c|   13 ++---
 include/linux/dcache.h|2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/Locking 
b/Documentation/filesystems/Locking
index d30fb2c..189ea98 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 
diff --git a/Documentation/filesystems/vfs.txt 
b/Documentation/filesystems/vfs.txt
index 9ace359..0035ac8 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -939,7 +939,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
-   int (*d_manage)(struct dentry *, bool);
+   int (*d_manage)(struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
 unsigned int);
 };
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index fa84bb8..0705daa 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file 
*file);
 static struct dentry *autofs4_lookup(struct inode *,
 struct dentry *, unsigned int);
 static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(struct path *, bool);
 static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
@@ -421,8 +421,9 @@ done:
return NULL;
 }
 
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(struct path *path, bool rcu_walk)
 {
+   struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
diff --git a/fs/namei.c b/fs/namei.c
index adb0414..e86b9d0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct 
nameidata *nd)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
break;
}
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
 }
 EXPORT_SYMBOL(follow_down_one);
 
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(struct path *path)
 {
-   return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
-   dentry->d_op->d_manage(dentry, true) : 0;
+   return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+   path->dentry->d_op->d_manage(path, true) : 0;
 }
 
 /*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, 
struct path *path,
 * Don't forget we might have a non-mountpoint managed dentry
 * that wants to block transit.
 */
-   switch (managed_dentry_rcu(path->dentry)) {
+   switch (managed_dentry_rcu(path)) {
case -ECHILD:
default:
return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
-   ret = path->dentry->d_op->d_manage(
-   path->dentry, false);
+   ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 5ff3e9a..ad2df92 100644
---