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page-server: Fix incompatibility of page server protocol

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It turned out (surprise surprise) that page server exchanges CR_FD_PAGEMAP
and CR_FD_SHMEM_PAGEMAP values in ps_iov_msg. The problem is that these
constants sit in enum and change their values from version to version %)

So here's the fixed version of the protocol including the backward compat
checks on all the values that could be met from older CRIUs (we're lucky
and they didn't intersect).

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Pavel Emelyanov
2017-07-14 18:30:57 +03:00
parent ae7a9a0758
commit ac05c73a7b
1 changed files with 58 additions and 1 deletions
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59
criu/page-xfer.c
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@@ -45,14 +45,61 @@ static void psi2iovec(struct page_server_iov *ps, struct iovec *iov)
#define PS_TYPE_BITS 8
#define PS_TYPE_MASK ((1 << PS_TYPE_BITS) - 1)
#define PS_TYPE_PID (1)
#define PS_TYPE_SHMEM (2)
/*
* XXX: When adding new types here check decode_pm_type for legacy
* numbers that can be met from older CRIUs
*/
static inline u64 encode_pm_id(int type, long id)
{
if (type == CR_FD_PAGEMAP)
type = PS_TYPE_PID;
else if (type == CR_FD_SHMEM_PAGEMAP)
type = PS_TYPE_SHMEM;
else {
BUG();
return 0;
}
return ((u64)id) << PS_TYPE_BITS | type;
}
static int decode_pm_type(u64 dst_id)
{
return dst_id & PS_TYPE_MASK;
int type;
/*
* Magic numbers below came from the older CRIU versions that
* errorneously used the changing CR_FD_* constants. The
* changes were made when we merged images together and moved
* the CR_FD_-s at the tail of the enum
*/
type = dst_id & PS_TYPE_MASK;
switch (type) {
case 10: /* 3.1 3.2 */
case 11: /* 1.3 1.4 1.5 1.6 1.7 1.8 2.* 3.0 */
case 16: /* 1.2 */
case 17: /* 1.0 1.1 */
case PS_TYPE_PID:
type = CR_FD_PAGEMAP;
break;
case 27: /* 1.3 */
case 28: /* 1.4 1.5 */
case 29: /* 1.6 1.7 */
case 32: /* 1.2 1.8 */
case 33: /* 1.0 1.1 3.1 3.2 */
case 34: /* 2.* 3.0 */
case PS_TYPE_SHMEM:
type = CR_FD_SHMEM_PAGEMAP;
break;
default:
type = -1;
break;
}
return type;
}
static long decode_pm_id(u64 dst_id)
@@ -435,6 +482,11 @@ static int page_server_check_parent(int sk, struct page_server_iov *pi)
type = decode_pm_type(pi->dst_id);
id = decode_pm_id(pi->dst_id);
if (type == -1) {
pr_err("Unknown pagemap type received\n");
return -1;
}
ret = check_parent_local_xfer(type, id);
if (ret < 0)
return -1;
@@ -502,6 +554,11 @@ static int page_server_open(int sk, struct page_server_iov *pi)
type = decode_pm_type(pi->dst_id);
id = decode_pm_id(pi->dst_id);
if (type == -1) {
pr_err("Unknown pagemap type received\n");
return -1;
}
pr_info("Opening %d/%ld\n", type, id);
page_server_close();