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locks: Add leases c/r for kernels v4.0 and older

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Information about locks in /proc/<pid>/fdinfo is presented only since
kernel v4.1. This patch adds logic to *note_file_lock* to match leases
and OFDs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Pavel Begunkov
2017-10-02 23:48:19 +03:00
committed by Andrei Vagin
parent b6dd25e939
commit 1fb5a051f7
1 changed files with 85 additions and 2 deletions
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87
criu/file-lock.c
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@@ -270,6 +270,80 @@ static int lock_ofd_check_fd(int lfd, struct file_lock *fl)
return 1;
}
static int lease_check_fd(int fd, int file_flags, struct file_lock *fl)
{
int file_lease_type, err;
int lease_type = fl->fl_ltype & (~LEASE_BREAKING);
if ((file_flags & O_ACCMODE) != O_RDONLY) {
/*
* Write OFD conflicts with any lease not associated
* with it, therefore there is can't be other lease
* or OFD for this file.
*/
return 1;
}
file_lease_type = fcntl(fd, F_GETLEASE);
if (file_lease_type < 0) {
pr_err("Can't get lease type\n");
return -1;
}
/*
* Only read OFDs can be present for the file. If
* read and write OFDs with at least one lease had
* presented, it would have conflicted.
*/
if (fl->fl_ltype & LEASE_BREAKING) {
/*
* Only read leases are possible for read OFDs
* and they all should be in breaking state,
* because the current one is.
*/
int compatible_type = file_lease_type;
if (compatible_type != F_UNLCK) {
pr_err("Lease doesn't conflicts but breaks\n");
return -1;
}
/*
* Due to activated breaking sequence we can't
* get actual lease type with F_GETLEASE.
* The err == 0 after lease upgrade means, that
* there is already read lease on OFD. Otherwise
* it would fail, because current read lease is
* still set and breaking.
*/
err = fcntl(fd, F_SETLEASE, F_RDLCK);
if (err < 0) {
if (errno != EAGAIN) {
pr_perror("Can't set lease (fd %i)", fd);
return -1;
}
return 0;
}
return 1;
} else {
/*
* The file can have only non-breaking read
* leases, because otherwise the current one
* also would have broke.
*/
if (lease_type != F_RDLCK) {
pr_err("Incorrect lease type\n");
return -1;
}
if (file_lease_type == F_UNLCK)
return 0;
if (file_lease_type == F_RDLCK)
return 1;
pr_err("Invalid file lease type\n");
return -1;
}
}
int note_file_lock(struct pid *pid, int fd, int lfd, struct fd_parms *p)
{
struct file_lock *fl;
@@ -299,8 +373,17 @@ int note_file_lock(struct pid *pid, int fd, int lfd, struct fd_parms *p)
if (fl->fl_owner != pid->real)
continue;
} else if (fl->fl_kind == FL_LEASE) {
pr_err("Leases are not supported for kernel <= v4.0");
return -1;
if (fl->owners_fd >= 0)
continue;
if (fl->fl_owner != pid->real &&
fl->real_owner != -1)
continue;
ret = lease_check_fd(lfd, p->flags, fl);
if (ret < 0)
return ret;
if (ret == 0)
continue;
} else /* fl->fl_kind == FL_FLOCK || fl->fl_kind == FL_OFD */ {
int ret;