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pid-namespaces-vs-locks-interaction 

fcntl(F_GETLK,..) can return pid of process for not current pid namespace
(if process is belonged to the several namespaces).  It is true also for
pids in /proc/locks.  So correct behavior is saving pointer to the struct
pid of the process lock owner.

Signed-off-by: Vitaliy Gusev <vgusev@openvz.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
Vitaliy Gusev 2008-01-17 00:07:08 +00:00 committed by J. Bruce Fields
parent 4321e01e7d
commit ab1f161165
2 changed files with 24 additions and 6 deletions
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29
fs/locks.c
View File

@ -125,6 +125,7 @@
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/rcupdate.h>
#include <linux/pid_namespace.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
@ -185,6 +186,7 @@ void locks_init_lock(struct file_lock *fl)
fl->fl_fasync = NULL;
fl->fl_owner = NULL;
fl->fl_pid = 0;
fl->fl_nspid = NULL;
fl->fl_file = NULL;
fl->fl_flags = 0;
fl->fl_type = 0;
@ -553,6 +555,8 @@ static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
{
list_add(&fl->fl_link, &file_lock_list);
fl->fl_nspid = get_pid(task_tgid(current));
/* insert into file's list */
fl->fl_next = *pos;
*pos = fl;
@ -584,6 +588,11 @@ static void locks_delete_lock(struct file_lock **thisfl_p)
if (fl->fl_ops && fl->fl_ops->fl_remove)
fl->fl_ops->fl_remove(fl);
if (fl->fl_nspid) {
put_pid(fl->fl_nspid);
fl->fl_nspid = NULL;
}
locks_wake_up_blocks(fl);
locks_free_lock(fl);
}
@ -646,14 +655,16 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
if (posix_locks_conflict(fl, cfl))
break;
}
if (cfl)
if (cfl) {
__locks_copy_lock(fl, cfl);
else
if (cfl->fl_nspid)
fl->fl_pid = pid_nr_ns(cfl->fl_nspid,
task_active_pid_ns(current));
} else
fl->fl_type = F_UNLCK;
unlock_kernel();
return;
}
EXPORT_SYMBOL(posix_test_lock);
/*
@ -2070,6 +2081,12 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
int id, char *pfx)
{
struct inode *inode = NULL;
unsigned int fl_pid;
if (fl->fl_nspid)
fl_pid = pid_nr_ns(fl->fl_nspid, task_active_pid_ns(current));
else
fl_pid = fl->fl_pid;
if (fl->fl_file != NULL)
inode = fl->fl_file->f_path.dentry->d_inode;
@ -2110,16 +2127,16 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
}
if (inode) {
#ifdef WE_CAN_BREAK_LSLK_NOW
seq_printf(f, "%d %s:%ld ", fl->fl_pid,
seq_printf(f, "%d %s:%ld ", fl_pid,
inode->i_sb->s_id, inode->i_ino);
#else
/* userspace relies on this representation of dev_t ;-( */
seq_printf(f, "%d %02x:%02x:%ld ", fl->fl_pid,
seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
MAJOR(inode->i_sb->s_dev),
MINOR(inode->i_sb->s_dev), inode->i_ino);
#endif
} else {
seq_printf(f, "%d <none>:0 ", fl->fl_pid);
seq_printf(f, "%d <none>:0 ", fl_pid);
}
if (IS_POSIX(fl)) {
if (fl->fl_end == OFFSET_MAX)

1
include/linux/fs.h
View File

@ -872,6 +872,7 @@ struct file_lock {
struct list_head fl_block; /* circular list of blocked processes */
fl_owner_t fl_owner;
unsigned int fl_pid;
struct pid *fl_nspid;
wait_queue_head_t fl_wait;
struct file *fl_file;
unsigned char fl_flags;