Commit 0b6b030f authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

bsdacct: switch from global bsd_acct_struct instance to per-pidns one 



Allocate the structure on the first call to sys_acct().  After this each
namespace, that ordered the accounting, will live with this structure till
its own death.

Two notes
- routines, that close the accounting on fs umount time use
  the init_pid_ns's acct by now;
- accounting routine accounts to dying task's namespace
  (also by now).

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6248b1b3

include/linux/acct.h

+3 −0
Original line number Diff line number Diff line
@@ -120,17 +120,20 @@ struct acct_v3 
struct vfsmount;

struct super_block;

struct pacct_struct;

struct pid_namespace;

extern void acct_auto_close_mnt(struct vfsmount *m);

extern void acct_auto_close(struct super_block *sb);

extern void acct_init_pacct(struct pacct_struct *pacct);

extern void acct_collect(long exitcode, int group_dead);

extern void acct_process(void);

extern void acct_exit_ns(struct pid_namespace *);

#else

#define acct_auto_close_mnt(x)	do { } while (0)

#define acct_auto_close(x)	do { } while (0)

#define acct_init_pacct(x)	do { } while (0)

#define acct_collect(x,y)	do { } while (0)

#define acct_process()		do { } while (0)

#define acct_exit_ns(ns)	do { } while (0)

#endif



/*

kernel/acct.c

+66 −18
Original line number Diff line number Diff line
@@ -93,8 +93,6 @@ struct bsd_acct_struct { 


static DEFINE_SPINLOCK(acct_lock);



static struct bsd_acct_struct acct_globals __cacheline_aligned;



/*

 * Called whenever the timer says to check the free space.

 */
@@ -176,7 +174,8 @@ out: 
 *

 * NOTE: acct_lock MUST be held on entry and exit.

 */

static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file)

static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,

		struct pid_namespace *ns)

{

	struct file *old_acct = NULL;

	struct pid_namespace *old_ns = NULL;
@@ -188,10 +187,11 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file) 
		acct->active = 0;

		acct->needcheck = 0;

		acct->file = NULL;

		acct->ns = NULL;

	}

	if (file) {

		acct->file = file;

		acct->ns = get_pid_ns(task_active_pid_ns(current));

		acct->ns = ns;

		acct->needcheck = 0;

		acct->active = 1;

		/* It's been deleted if it was used before so this is safe */
@@ -204,7 +204,6 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file) 
		spin_unlock(&acct_lock);

		do_acct_process(acct, old_ns, old_acct);

		filp_close(old_acct, NULL);

		put_pid_ns(old_ns);

		spin_lock(&acct_lock);

	}

}
@@ -213,6 +212,8 @@ static int acct_on(char *name) 
{

	struct file *file;

	int error;

	struct pid_namespace *ns;

	struct bsd_acct_struct *acct = NULL;



	/* Difference from BSD - they don't do O_APPEND */

	file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
@@ -229,18 +230,34 @@ static int acct_on(char *name) 
		return -EIO;

	}



	ns = task_active_pid_ns(current);

	if (ns->bacct == NULL) {

		acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);

		if (acct == NULL) {

			filp_close(file, NULL);

			return -ENOMEM;

		}

	}



	error = security_acct(file);

	if (error) {

		kfree(acct);

		filp_close(file, NULL);

		return error;

	}



	spin_lock(&acct_lock);

	if (ns->bacct == NULL) {

		ns->bacct = acct;

		acct = NULL;

	}



	mnt_pin(file->f_path.mnt);

	acct_file_reopen(&acct_globals, file);

	acct_file_reopen(ns->bacct, file, ns);

	spin_unlock(&acct_lock);



	mntput(file->f_path.mnt); /* it's pinned, now give up active reference */

	kfree(acct);



	return 0;

}
@@ -270,10 +287,16 @@ asmlinkage long sys_acct(const char __user *name) 
		error = acct_on(tmp);

		putname(tmp);

	} else {

		struct bsd_acct_struct *acct;



		acct = task_active_pid_ns(current)->bacct;

		if (acct == NULL)

			return 0;



		error = security_acct(NULL);

		if (!error) {

			spin_lock(&acct_lock);

			acct_file_reopen(&acct_globals, NULL);

			acct_file_reopen(acct, NULL, NULL);

			spin_unlock(&acct_lock);

		}

	}
@@ -289,9 +312,15 @@ asmlinkage long sys_acct(const char __user *name) 
 */

void acct_auto_close_mnt(struct vfsmount *m)

{

	struct bsd_acct_struct *acct;



	acct = init_pid_ns.bacct;

	if (acct == NULL)

		return;



	spin_lock(&acct_lock);

	if (acct_globals.file && acct_globals.file->f_path.mnt == m)

		acct_file_reopen(&acct_globals, NULL);

	if (acct->file && acct->file->f_path.mnt == m)

		acct_file_reopen(acct, NULL, NULL);

	spin_unlock(&acct_lock);

}
@@ -304,10 +333,29 @@ void acct_auto_close_mnt(struct vfsmount *m) 
 */

void acct_auto_close(struct super_block *sb)

{

	struct bsd_acct_struct *acct;



	acct = init_pid_ns.bacct;

	if (acct == NULL)

		return;



	spin_lock(&acct_lock);

	if (acct->file && acct->file->f_path.mnt->mnt_sb == sb)

		acct_file_reopen(acct, NULL, NULL);

	spin_unlock(&acct_lock);

}



void acct_exit_ns(struct pid_namespace *ns)

{

	struct bsd_acct_struct *acct;



	spin_lock(&acct_lock);

	if (acct_globals.file &&

	    acct_globals.file->f_path.mnt->mnt_sb == sb) {

		acct_file_reopen(&acct_globals, NULL);

	acct = ns->bacct;

	if (acct != NULL) {

		if (acct->file != NULL)

			acct_file_reopen(acct, NULL, NULL);



		kfree(acct);

	}

	spin_unlock(&acct_lock);

}
@@ -587,25 +635,25 @@ void acct_collect(long exitcode, int group_dead) 
void acct_process(void)

{

	struct file *file = NULL;

	struct pid_namespace *ns;

	struct pid_namespace *ns = task_active_pid_ns(current);

	struct bsd_acct_struct *acct;



	acct = ns->bacct;

	/*

	 * accelerate the common fastpath:

	 */

	if (!acct_globals.file)

	if (!acct || !acct->file)

		return;



	spin_lock(&acct_lock);

	file = acct_globals.file;

	file = acct->file;

	if (unlikely(!file)) {

		spin_unlock(&acct_lock);

		return;

	}

	get_file(file);

	ns = get_pid_ns(acct_globals.ns);

	spin_unlock(&acct_lock);



	do_acct_process(&acct_globals, ns, file);

	do_acct_process(acct, ns, file);

	fput(file);

	put_pid_ns(ns);

}

kernel/pid_namespace.c

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/pid_namespace.h>

#include <linux/syscalls.h>

#include <linux/err.h>

#include <linux/acct.h>



#define BITS_PER_PAGE		(PAGE_SIZE*8)
@@ -181,6 +182,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) 


	/* Child reaper for the pid namespace is going away */

	pid_ns->child_reaper = NULL;

	acct_exit_ns(pid_ns);

	return;

}

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