page-xfer: Don't expect that page server cmd is read in one call

There's a standard way of doing this -- the MSG_WAITALL flag that
works even for TCP sockets.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
irmap: Add option that forces fsnotify watches paths resolve

When migrating container with copying its FS, the inode numbers
and thus their handles wil change. This will make the restore of
inotify/fanotify fail, since they do it via fhandles.

We've already faced the problems with fsnotifies on NFS -- they
don't work there. To address this an irmap cache is created on
pre-dump, so to resolve the issue with changed inodes during
migration, we can force the irmap cache build.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
irmap: Properly compare stat vs proc devices

The s_dev value we see in irmap is get from proc file and is
raw kernel dev_t. We compare this value to the device get from
stat syscall, which is old-style dev_t (with less bits for minor).

Thus, need to convert kernel dev_t to stat's dev_t for proper
comparison.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
deduplication: fix bug in auto-dedup when it is on page-server

No need to check opts.use_page_server, because in write_pagemap_loc
write is local anyway. it appeared that on page-server when saving
pages to images opts.use_page_server=true and no auto-dedup started,
so images were not null as expected.

Signed-off-by: Tikhomirov Pavel <snorcht@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
proc_parse: Borrow vmi iif there is file referenced

Otherwise we migh propagate previous vfi status
to vmas which actually don't match.

 | (00.005471) 0x2b79227d6000-0x2b79227d8000 (8K) prot 0x5 flags 0x22 off 0 reg vdso ap  shmid: 0
 | (00.005473) 0x2b79227d8000-0x2b79227da000 (8K) prot 0x3 flags 0x22 off 0 reg vdso ap  shmid: 0
 | (00.005475) 0x2b79227f1000-0x2b79227f2000 (4K) prot 0x3 flags 0x22 off 0 reg vdso ap  shmid: 0
 | (00.005476) 0x2b79227f2000-0x2b79227f4000 (8K) prot 0x3 flags 0x22 off 0 reg vdso ap  shmid: 0

Tested-by: Pavel Tikhomirov <snorcht@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>