For linked remaps we'll use similar technique as for ghost
files, but lighter. For that sake make reg_file_info remap
to file_remap, not to the whole host_file.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Otherwise there is a race between files with same names:
link(name -> ghost) link(name->ghost)
open(name)
unlink(name)
open(name) -> ENOENT
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
A ghost file is used for restoring descriptors of an unlinked file.
It is created, opened and deleted.
Currently ghost files are collected in root task and then removed
by crtools when everybody is restored. This scheme doesn't work,
ghost_file_list is not shared, plus tasks may live in different mount
namespace.
It was broken by the following commit:
bd4e5d2f restore: prepare shared objects after initializing namespaces
We can't just move clear_ghost_files(), because we need to wait, until
all processes have not opened a ghost file.
We can add one more global barrier or move clear_ghost_files() in
a restore code bellow an existent barrier.
Here is a better sollution, a gost file is deleted by the last user.
v2: Use the type atomic_t and fix a commit message.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This patch switches reg_file_entry structure with RegFileEntry
protobuf entry. Note that there a few nits remains
- old fown_t structure doesn't scale well with FownEntry from
RegFileEntry, so to not mess with rest of crtools code
I've added a couple of opencoded copy operands, will clean
this aspect up once rest of code is converted
- the "show" procedure doesn't print fown for same reason
v2:
- rename fown_t to fown_entry in .proto
v3:
- don't print nil symbol on show
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Don't push open cb onto reg_file_into, pass it into regfiles engine
as an argument.
Note: I haven't merged the fifo zdtms yet, thus this patch is untested.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Checkpoint and restore of fifo is similar to
pipes c/r except the pipe end-points are named
file.
Because the fifo has a name we use regular files
facility for fifo path c/r.
Still there is a trick used to "open" fifo:
the opening procedure migh sleep if a fifo's peer
is not yet opened, so before doing a real open
we yield a fake open procedure (with O_RDWR flag)
which prevents us from sleeping even if peer
is not yet ready. Also we need writable fifo
end to restore data queued.
v2:
- add open/priv members to reg_file_info
- make open_fifo_fd to use open_fe_fd
- comment on pipe_id
- make sure the fifo data is not restored twice
v3:
- drop useless fixme comment and add sane one
v4:
- Use restore_data flag to escape data restore duplication
- Use S_ISREG for file contents copying
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Instead of spreading regular files handling code over
files.c and cr-dump.c move it to files-reg.c.
This allows to extend regular file handling code in
future without disturbing other source files and
make code logically coupled, where files.c is mostly
a place for general file handling code unrelated to
file type specifics.
While mostly it was code tossing there is some change
I have to notice -- the structure ghost_file was previously
declared in two paces cr-dump.c and files.c, in cr-dump.c
it was used for dumping while in files.c it was used
for restore. The structure had different members.
So to resolve this conflict the ghost_file structure
was renamed to ghost_file_dumpee.
Nothing else is changed.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
