[CRIU] [PATCH 7/9] mounts: if a mount can't be mounted, it is queued in postpone list
Andrey Vagin
avagin at openvz.org
Tue Jul 9 07:05:54 EDT 2013
Try to restore mounts while a postpone list isn't empty and check
that each iteration has some progress, otherwice it will fails for
preventing infinite loops
Signed-off-by: Andrey Vagin <avagin at openvz.org>
---
include/proc_parse.h | 2 ++
mount.c | 40 ++++++++++++++++++++++++++++++++++++----
2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/include/proc_parse.h b/include/proc_parse.h
index 1325424..85bde36 100644
--- a/include/proc_parse.h
+++ b/include/proc_parse.h
@@ -123,6 +123,8 @@ struct mount_info {
struct list_head mnt_slave_list;/* list of slave mounts */
struct list_head mnt_slave; /* slave list entry */
struct mount_info *mnt_master; /* slave is on master->mnt_slave_list */
+
+ struct list_head postpone;
};
struct proc_posix_timer {
diff --git a/mount.c b/mount.c
index 0609ded..fae9513 100644
--- a/mount.c
+++ b/mount.c
@@ -533,12 +533,25 @@ int dump_mnt_ns(int ns_pid, struct cr_fdset *fdset)
return 0;
}
-#define MNT_TREE_WALK(_r, _el, _fn_f, _fn_r) do { \
+static int mount_progress;
+
+#define MNT_TREE_WALK(_r, _el, _fn_f, _fn_r, _plist) do { \
struct mount_info *_mi = _r; \
\
while (1) { \
- if (_fn_f(_mi)) \
+ int ret; \
+ \
+ ret = _fn_f(_mi); \
+ if (ret < 0) \
return -1; \
+ else if (ret > 0) { \
+ list_add_tail(&_mi->postpone, _plist); \
+ goto up; \
+ } \
+ \
+ list_del(&_mi->postpone); \
+ mount_progress++; \
+ \
if (!list_empty(&_mi->children)) { \
_mi = list_entry(_mi->children._el, \
struct mount_info, siblings); \
@@ -564,13 +577,32 @@ int dump_mnt_ns(int ns_pid, struct cr_fdset *fdset)
static int mnt_tree_for_each(struct mount_info *m,
int (*fn)(struct mount_info *))
{
- MNT_TREE_WALK(m, next, fn, MNT_WALK_NONE);
+ static LIST_HEAD(postpone);
+
+ list_add(&m->postpone, &postpone);
+
+ while (!list_empty(&postpone)) {
+ int old = mount_progress;
+ list_for_each_entry(m, &postpone, postpone)
+ MNT_TREE_WALK(m, next, fn, MNT_WALK_NONE, &postpone);
+ if (old == mount_progress) {
+ pr_err("A few mount points can't be mounted");
+ list_for_each_entry(m, &postpone, postpone) {
+ pr_err("%d:%d %s %s %s\n", m->mnt_id,
+ m->parent_mnt_id, m->root,
+ m->mountpoint, m->source);
+ }
+ return -1;
+ }
+ }
+
+ return 0;
}
static int mnt_tree_for_each_reverse(struct mount_info *m,
int (*fn)(struct mount_info *))
{
- MNT_TREE_WALK(m, prev, MNT_WALK_NONE, fn);
+ MNT_TREE_WALK(m, prev, MNT_WALK_NONE, fn, (struct list_head *) NULL);
}
static char *resolve_source(struct mount_info *mi)
--
1.8.3.1
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