[PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[Eric W. Biederman]

It appears we overlooked support for removing generic proc files
when we added support for multiple proc super blocks.  Handle
that now.

Signed-off-by: Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
---
 fs/proc/generic.c  |   38 +++++++++++++++++++++-----------------
 fs/proc/internal.h |    2 ++
 fs/proc/root.c     |    2 +-
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 1bdb624..3906770 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -561,28 +561,32 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
 static void proc_kill_inodes(struct proc_dir_entry *de)
 {
 	struct list_head *p;
-	struct super_block *sb = proc_mnt->mnt_sb;
+	struct super_block *sb;
 
 	/*
 	 * Actually it's a partial revoke().
 	 */
-	file_list_lock();
-	list_for_each(p, &sb->s_files) {
-		struct file * filp = list_entry(p, struct file, f_u.fu_list);
-		struct dentry * dentry = filp->f_path.dentry;
-		struct inode * inode;
-		const struct file_operations *fops;
-
-		if (dentry->d_op != &proc_dentry_operations)
-			continue;
-		inode = dentry->d_inode;
-		if (PDE(inode) != de)
-			continue;
-		fops = filp->f_op;
-		filp->f_op = NULL;
-		fops_put(fops);
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
+		file_list_lock();
+		list_for_each(p, &sb->s_files) {
+			struct file * filp = list_entry(p, struct file, f_u.fu_list);
+			struct dentry * dentry = filp->f_path.dentry;
+			struct inode * inode;
+			const struct file_operations *fops;
+
+			if (dentry->d_op != &proc_dentry_operations)
+				continue;
+			inode = dentry->d_inode;
+			if (PDE(inode) != de)
+				continue;
+			fops = filp->f_op;
+			filp->f_op = NULL;
+			fops_put(fops);
+		}
+		file_list_unlock();
 	}
-	file_list_unlock();
+	spin_unlock(&sb_lock);
 }
 
 static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 1820eb2..1b2b6c6 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -78,3 +78,5 @@ static inline int proc_fd(struct inode *inode)
 {
 	return PROC_I(inode)->fd;
 }
+
+extern struct file_system_type proc_fs_type;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index ec9cb3b..1f86bb8 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -98,7 +98,7 @@ static void proc_kill_sb(struct super_block *sb)
 	put_pid_ns(ns);
 }
 
-static struct file_system_type proc_fs_type = {
+struct file_system_type proc_fs_type = {
 	.name		= "proc",
 	.get_sb		= proc_get_sb,
 	.kill_sb	= proc_kill_sb,
-- 
1.5.3.rc6.17.g1911

Re: [PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[Pavel Emelyanov]

Eric W. Biederman wrote:
> It appears we overlooked support for removing generic proc files
> when we added support for multiple proc super blocks.  Handle
> that now.
> 
> Signed-off-by: Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>

AFAIS this is just making the kill for all the super blocks
we have.

Acked-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

> ---
>  fs/proc/generic.c  |   38 +++++++++++++++++++++-----------------
>  fs/proc/internal.h |    2 ++
>  fs/proc/root.c     |    2 +-
>  3 files changed, 24 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/proc/generic.c b/fs/proc/generic.c
> index 1bdb624..3906770 100644
> --- a/fs/proc/generic.c
> +++ b/fs/proc/generic.c
> @@ -561,28 +561,32 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
>  static void proc_kill_inodes(struct proc_dir_entry *de)
>  {
>  	struct list_head *p;
> -	struct super_block *sb = proc_mnt->mnt_sb;
> +	struct super_block *sb;
>  
>  	/*
>  	 * Actually it's a partial revoke().
>  	 */
> -	file_list_lock();
> -	list_for_each(p, &sb->s_files) {
> -		struct file * filp = list_entry(p, struct file, f_u.fu_list);
> -		struct dentry * dentry = filp->f_path.dentry;
> -		struct inode * inode;
> -		const struct file_operations *fops;
> -
> -		if (dentry->d_op != &proc_dentry_operations)
> -			continue;
> -		inode = dentry->d_inode;
> -		if (PDE(inode) != de)
> -			continue;
> -		fops = filp->f_op;
> -		filp->f_op = NULL;
> -		fops_put(fops);
> +	spin_lock(&sb_lock);
> +	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
> +		file_list_lock();
> +		list_for_each(p, &sb->s_files) {
> +			struct file * filp = list_entry(p, struct file, f_u.fu_list);
> +			struct dentry * dentry = filp->f_path.dentry;
> +			struct inode * inode;
> +			const struct file_operations *fops;
> +
> +			if (dentry->d_op != &proc_dentry_operations)
> +				continue;
> +			inode = dentry->d_inode;
> +			if (PDE(inode) != de)
> +				continue;
> +			fops = filp->f_op;
> +			filp->f_op = NULL;
> +			fops_put(fops);
> +		}
> +		file_list_unlock();
>  	}
> -	file_list_unlock();
> +	spin_unlock(&sb_lock);
>  }
>  
>  static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
> diff --git a/fs/proc/internal.h b/fs/proc/internal.h
> index 1820eb2..1b2b6c6 100644
> --- a/fs/proc/internal.h
> +++ b/fs/proc/internal.h
> @@ -78,3 +78,5 @@ static inline int proc_fd(struct inode *inode)
>  {
>  	return PROC_I(inode)->fd;
>  }
> +
> +extern struct file_system_type proc_fs_type;
> diff --git a/fs/proc/root.c b/fs/proc/root.c
> index ec9cb3b..1f86bb8 100644
> --- a/fs/proc/root.c
> +++ b/fs/proc/root.c
> @@ -98,7 +98,7 @@ static void proc_kill_sb(struct super_block *sb)
>  	put_pid_ns(ns);
>  }
>  
> -static struct file_system_type proc_fs_type = {
> +struct file_system_type proc_fs_type = {
>  	.name		= "proc",
>  	.get_sb		= proc_get_sb,
>  	.kill_sb	= proc_kill_sb,

Re: [Devel] Re: [PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[Alexey Dobriyan]

On Thu, Nov 01, 2007 at 06:48:25PM +0300, Pavel Emelyanov wrote:
> Eric W. Biederman wrote:
> > It appears we overlooked support for removing generic proc files
> > when we added support for multiple proc super blocks.  Handle
> > that now.
> > 
> > Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> 
> AFAIS this is just making the kill for all the super blocks
> we have.
> 
> Acked-by: Pavel Emelyanov <xemul@openvz.org>

bzzrt, this function is executed only for directories and symlinks,
obviously buggy (you can't flip ->f_op on live file) and is going away
after readdir/rmmod races for directories will be dealt the same way as
for regular file.

> > --- a/fs/proc/generic.c
> > +++ b/fs/proc/generic.c
> > @@ -561,28 +561,32 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
> >  static void proc_kill_inodes(struct proc_dir_entry *de)
> >  {
> >  	struct list_head *p;
> > -	struct super_block *sb = proc_mnt->mnt_sb;
> > +	struct super_block *sb;
> >  
> >  	/*
> >  	 * Actually it's a partial revoke().
> >  	 */
> > -	file_list_lock();
> > -	list_for_each(p, &sb->s_files) {
> > -		struct file * filp = list_entry(p, struct file, f_u.fu_list);
> > -		struct dentry * dentry = filp->f_path.dentry;
> > -		struct inode * inode;
> > -		const struct file_operations *fops;
> > -
> > -		if (dentry->d_op != &proc_dentry_operations)
> > -			continue;
> > -		inode = dentry->d_inode;
> > -		if (PDE(inode) != de)
> > -			continue;
> > -		fops = filp->f_op;
> > -		filp->f_op = NULL;
> > -		fops_put(fops);
> > +	spin_lock(&sb_lock);
> > +	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
> > +		file_list_lock();
> > +		list_for_each(p, &sb->s_files) {
> > +			struct file * filp = list_entry(p, struct file, f_u.fu_list);
> > +			struct dentry * dentry = filp->f_path.dentry;
> > +			struct inode * inode;
> > +			const struct file_operations *fops;
> > +
> > +			if (dentry->d_op != &proc_dentry_operations)
> > +				continue;
> > +			inode = dentry->d_inode;
> > +			if (PDE(inode) != de)
> > +				continue;
> > +			fops = filp->f_op;
> > +			filp->f_op = NULL;
> > +			fops_put(fops);
> > +		}
> > +		file_list_unlock();
> >  	}
> > -	file_list_unlock();
> > +	spin_unlock(&sb_lock);
> >  }

Yup, all this bogo-revoke is going away RSN. you just kicked my lazy ass.

Re: [Devel] Re: [PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[Eric W. Biederman]

Alexey Dobriyan <adobriyan@sw.ru> writes:

> Yup, all this bogo-revoke is going away RSN. you just kicked my lazy ass.

As long as the issue is fixed I don't care.

Eric

Re: [PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[sukadev]

Pavel Emelianov [xemul@openvz.org] wrote:
| Eric W. Biederman wrote:
| > It appears we overlooked support for removing generic proc files
| > when we added support for multiple proc super blocks.  Handle
| > that now.
| > 
| > Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| 
| AFAIS this is just making the kill for all the super blocks
| we have.
| 
| Acked-by: Pavel Emelyanov <xemul@openvz.org>

Acked-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>

| 
| > ---
| >  fs/proc/generic.c  |   38 +++++++++++++++++++++-----------------
| >  fs/proc/internal.h |    2 ++
| >  fs/proc/root.c     |    2 +-
| >  3 files changed, 24 insertions(+), 18 deletions(-)
| > 
| > diff --git a/fs/proc/generic.c b/fs/proc/generic.c
| > index 1bdb624..3906770 100644
| > --- a/fs/proc/generic.c
| > +++ b/fs/proc/generic.c
| > @@ -561,28 +561,32 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
| >  static void proc_kill_inodes(struct proc_dir_entry *de)
| >  {
| >  	struct list_head *p;
| > -	struct super_block *sb = proc_mnt->mnt_sb;
| > +	struct super_block *sb;
| >  
| >  	/*
| >  	 * Actually it's a partial revoke().
| >  	 */
| > -	file_list_lock();
| > -	list_for_each(p, &sb->s_files) {
| > -		struct file * filp = list_entry(p, struct file, f_u.fu_list);
| > -		struct dentry * dentry = filp->f_path.dentry;
| > -		struct inode * inode;
| > -		const struct file_operations *fops;
| > -
| > -		if (dentry->d_op != &proc_dentry_operations)
| > -			continue;
| > -		inode = dentry->d_inode;
| > -		if (PDE(inode) != de)
| > -			continue;
| > -		fops = filp->f_op;
| > -		filp->f_op = NULL;
| > -		fops_put(fops);
| > +	spin_lock(&sb_lock);
| > +	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
| > +		file_list_lock();
| > +		list_for_each(p, &sb->s_files) {
| > +			struct file * filp = list_entry(p, struct file, f_u.fu_list);
| > +			struct dentry * dentry = filp->f_path.dentry;
| > +			struct inode * inode;
| > +			const struct file_operations *fops;
| > +
| > +			if (dentry->d_op != &proc_dentry_operations)
| > +				continue;
| > +			inode = dentry->d_inode;
| > +			if (PDE(inode) != de)
| > +				continue;
| > +			fops = filp->f_op;
| > +			filp->f_op = NULL;
| > +			fops_put(fops);
| > +		}
| > +		file_list_unlock();
| >  	}
| > -	file_list_unlock();
| > +	spin_unlock(&sb_lock);
| >  }
| >  
| >  static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
| > diff --git a/fs/proc/internal.h b/fs/proc/internal.h
| > index 1820eb2..1b2b6c6 100644
| > --- a/fs/proc/internal.h
| > +++ b/fs/proc/internal.h
| > @@ -78,3 +78,5 @@ static inline int proc_fd(struct inode *inode)
| >  {
| >  	return PROC_I(inode)->fd;
| >  }
| > +
| > +extern struct file_system_type proc_fs_type;
| > diff --git a/fs/proc/root.c b/fs/proc/root.c
| > index ec9cb3b..1f86bb8 100644
| > --- a/fs/proc/root.c
| > +++ b/fs/proc/root.c
| > @@ -98,7 +98,7 @@ static void proc_kill_sb(struct super_block *sb)
| >  	put_pid_ns(ns);
| >  }
| >  
| > -static struct file_system_type proc_fs_type = {
| > +struct file_system_type proc_fs_type = {
| >  	.name		= "proc",
| >  	.get_sb		= proc_get_sb,
| >  	.kill_sb	= proc_kill_sb,