When an image of a certian type is not found, CRIU sometimes
fails, sometimes ignores this fact. I propose to ignore this
fact always and treat absent images and those containing no
objects inside (i.e. -- empty). If the latter code flow will
_need_ objects, then criu will fail later.
Why object will be explicitly required? For example, due to
restoring code reading the image with pb_read_one, w/o the
_eof suffix thus required the object to be in the image.
Another example is objects dependencies. E.g. fdinfo objects
require various files objects. So missing image files will
result in non-resolved searches later.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Current code doesn't make any difference between OPT and no-OPT
except for the message is printed or not in the open_image().
So this particular change changes nothing but the availability of
this message.
In the next patches I wil introduce "empty images" to deal with
the ENOENT situation in a more graceful manner.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We want to have buffered images to speed up dump and,
slightly, restore. Right now we use plan file descriptors
to write and read images to/from. Making them buffered
cannot be gracefully done on plain fds, so introduce
a new class.
This will also help if (when?) we will want to do more
complex changes with images, e.g. store them all in one
file or send them directly to the network.
For now the cr_img just contains one int _fd variable.
This patch chages the prototype of open_image() to
return struct cr_img *, pb_(read|write)* to accept one
and fixes the compilation of the rest of the code :)
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
There will be no int-fd soon, so one more preparation
to this fact.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Since we're going to switch from int-fd-s to class-image
soon the fdset name will not fit into the new terminology.
This patch is
sed -e 's/fdset/imgset/g' -i *
sed -e 's/imgset_fd/img_from_set/g' -i *
git mv include/fdset.h include/imgset.h
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
BTRFS returns subvolume dev-id instead of superblock dev-id,
in such case return device obtained from mountinfo (ie subvolume0).
v2: fix up devices only for btrfs files.
v3: use phys_stat_dev_match instead of phys_stat_resolve_dev
v4: fix cosmetic whims
Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
These guys may have pids that are not met in pstree.
This is not the reason for skipping those, try to
resolve flocks anyway.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
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>
Currently we keep the lock type (posix/flock) till the
time we dump it, then "decode" it into binary value.
I will need the easy-to-check one early, so parse the
kind in proc_parse.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
If we're dumping namespaced tasks, the fl_owner value we see
are the real pids of tasks, while we need virtual ones.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
They are now in per-pid images, but every entry contains a
pid to which it "belongs". This belonging is fake -- it's
just a pid of a task who placed the lock, while locks really
belong to files. We even have a bug when task that locked
a file exited and "delegated" the lock to its child.
This images merge reduces the amount of image files criu
generates and may simplify the fix of mentioned above issue.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
During the time some files become obsolete and might be missing
in checkpoint image set, but to keep backward compatibility we
still trying to open them, which might print out error like
| Unable to open 'path-to-file'
and confuse a reader why criu prints error but continue working.
To eliminate this problem O_OPT flag has been introduced in
commit 16b5692061, which suppress error message priting
if the flag is set.
Now start using O_OPT in the following functions
- open_irmap_cache: irmap cache is relatively new optional feature
- prepare_rlimits, open_signal_image, restore_file_locks,
prepare_fd_pid, prepare_mm_pid, collect_image: all these
helpers are trying to open image files which can be missing.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
According to the file lock information from the image, we recall
flock or fcntl with proper parameters, so we can rehold the file
locks as we were dumped.
We only support flock and posix file locks so far.
Changelog since the initial version:
a. Use prepare_file_locks instead of restore function directly.
b. Fix some bugs.
Originally-signed-off-by: Zheng Gu <cengku.gu@huawei.com>
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Dump file locks' necessary entries to the image, we only support flock and
posix file lock right now.
Changelog since the initial version:
We got file lock info from global list, so the dump_task_file_locks
can be much simpler.
Originally-signed-off-by: Zheng Gu <cengku.gu@huawei.com>
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We collect all file locks to a golbal list, so we can use them easily
in dump_one_task. For optimizaton, we only collect file locks hold by
tasks in the pstree.
Thanks to the ptrace-seize machanism, we can aviod the blocked file lock
issue, makes the work simpler.
Right now, the check handles only one situation:
-- Dumping tasks with file locks hold without the -l option.
This covers for the most part. But we still need some more work to make
it perfect robust in the future.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
