WIth current code we have smth like

1) If file was opened with O_WRONLY, this mode is simply lost.
2) If file was opened with O_RDWR, but mapping is private, resulting mode will be O_RDONLY

The correct place to get fd open flags for file mappings is
/proc/<pid>/map_files.
An attempt tp speculate on "shared" and "maywrite" bits doesn't garantee,
that file will be opened with correct permissions on restore.
Here is an example:

Process mapping (read/write):

# cat /proc/481943/maps | grep 7f7108077000-7f7108078000
7f7108077000-7f7108078000 rw-p 00001000 00:35 7 <snip>

1) Before suspend:

# ls -l /proc/481427/map_files/7f7108077000-7f7108078000
lrw------- <snip> /proc/481427/map_files/7f7108077000-7f7108078000 -> <snip>

2) After restore:

# ls -l /proc/481943/map_files/7f7108077000-7f7108078000
lr-------- <snip> /proc/481943/map_files/7f7108077000-7f7108078000 -> <snip>

Write bit is lost.

This patch set vma->e->fdflags as /proc/<pid>/map_files/<vma> open mode.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>