mirror of
https://github.com/checkpoint-restore/criu.git
synced 2026-01-23 02:14:37 +00:00
53537f52c8
We have a problem with file locks (bug #2512) -- the /proc/locks file shows the ID of lock creator, not the owner. Thus, if the creator died, but holder is still alive, criu fails to dump the lock held by latter task. The proposal is to find who _might_ hold the lock by checking for dev:inode pairs on lock vs file descriptors being dumped. If the creator of the lock is still alive, then he will take the priority. One thing to note about flocks -- these belong to file entries, not to tasks. Thus, when we meet one, we should check whether the flock is really held by task's FD by trying to set yet another one. In case of success -- lock really belongs to fd we dump, in case it doesn't trylock should fail. At the very end -- walk the list of locks and dump them all at once, which is possible by merge of per-task file-locks images into one global one. Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
#ifndef __FILE_LOCK_H__
|
|
#define __FILE_LOCK_H__
|
|
|
|
#include "list.h"
|
|
|
|
#include "protobuf.h"
|
|
#include "protobuf/file-lock.pb-c.h"
|
|
|
|
#define FL_UNKNOWN -1
|
|
#define FL_POSIX 1
|
|
#define FL_FLOCK 2
|
|
|
|
/* for posix fcntl() and lockf() */
|
|
#ifndef F_RDLCK
|
|
#define F_RDLCK 0
|
|
#define F_WRLCK 1
|
|
#define F_UNLCK 2
|
|
#endif
|
|
|
|
/* operations for bsd flock(), also used by the kernel implementation */
|
|
#define LOCK_SH 1 /* shared lock */
|
|
#define LOCK_EX 2 /* exclusive lock */
|
|
#define LOCK_NB 4 /* or'd with one of the above to prevent
|
|
blocking */
|
|
#define LOCK_UN 8 /* remove lock */
|
|
|
|
#define LOCK_MAND 32 /* This is a mandatory flock ... */
|
|
#define LOCK_READ 64 /* which allows concurrent read operations */
|
|
#define LOCK_WRITE 128 /* which allows concurrent write operations */
|
|
#define LOCK_RW 192 /* which allows concurrent read & write ops */
|
|
|
|
struct file_lock {
|
|
long long fl_id;
|
|
int fl_kind;
|
|
int fl_ltype;
|
|
|
|
pid_t fl_owner;
|
|
int maj, min;
|
|
unsigned long i_no;
|
|
long long start;
|
|
char end[32];
|
|
|
|
struct list_head list; /* list of all file locks */
|
|
|
|
int real_owner;
|
|
int owners_fd;
|
|
};
|
|
|
|
extern struct list_head file_lock_list;
|
|
|
|
extern struct file_lock *alloc_file_lock(void);
|
|
extern void free_file_locks(void);
|
|
|
|
extern int prepare_file_locks(int pid);
|
|
extern struct collect_image_info file_locks_cinfo;
|
|
|
|
struct pid;
|
|
struct fd_parms;
|
|
extern int note_file_lock(struct pid *, int fd, int lfd, struct fd_parms *);
|
|
extern int dump_file_locks(void);
|
|
|
|
#define OPT_FILE_LOCKS "file-locks"
|
|
|
|
#endif /* __FILE_LOCK_H__ */
|