[CRIU] [PATCH 01/10] mount: link dependent mounts (v3)
Andrey Vagin
avagin at openvz.org
Thu Aug 29 10:55:38 EDT 2013
All shared mounts from one group are connected to circular list.
All slave are added into the proper master list.
v2: change variable name and fix a bug about adding shared mounts in a
circular list.
v3: handle errors of collect_shared
Signed-off-by: Andrey Vagin <avagin at openvz.org>
---
include/proc_parse.h | 5 ++++
mount.c | 85 ++++++++++++++++++++++++++++++----------------------
2 files changed, 55 insertions(+), 35 deletions(-)
diff --git a/include/proc_parse.h b/include/proc_parse.h
index 8c2c36e..99255c4 100644
--- a/include/proc_parse.h
+++ b/include/proc_parse.h
@@ -116,6 +116,11 @@ struct mount_info {
struct mount_info *parent;
struct list_head children;
struct list_head siblings;
+
+ struct list_head mnt_share; /* circular list of shared mounts */
+ 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 proc_posix_timer {
diff --git a/mount.c b/mount.c
index c950992..446a03e 100644
--- a/mount.c
+++ b/mount.c
@@ -194,6 +194,51 @@ static void mnt_tree_show(struct mount_info *tree, int off)
pr_info("%*s<--\n", off, "");
}
+static int collect_shared(struct mount_info *info)
+{
+ struct mount_info *m, *t;
+
+ /*
+ * If we have a shared mounts, both master
+ * slave targets are to be present in mount
+ * list, otherwise we can't be sure if we can
+ * recreate the scheme later on restore.
+ */
+ for (m = info; m; m = m->next) {
+ bool need_share, need_master;
+
+ need_share = m->shared_id && list_empty(&m->mnt_share);
+ need_master = m->master_id;
+
+ for (t = info; t && (need_share || need_master); t = t->next) {
+ if (t == m)
+ continue;
+ if (need_master && t->shared_id == m->master_id) {
+ pr_debug("The mount %d is slave for %d\n", m->mnt_id, t->mnt_id);
+ list_add(&m->mnt_slave, &t->mnt_slave_list);
+ m->mnt_master = t;
+ need_master = false;
+ }
+
+ /* Collect all mounts from this group */
+ if (need_share && t->shared_id == m->shared_id) {
+ pr_debug("Mount %d is shared with %d group %d\n",
+ m->mnt_id, t->mnt_id, m->shared_id);
+ list_add(&t->mnt_share, &m->mnt_share);
+ }
+ }
+
+ if (need_master) {
+ pr_err("Mount %d (master_id: %d shared_id: %d) "
+ "has unreachable sharing\n", m->mnt_id,
+ m->master_id, m->shared_id);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
static struct mount_info *mnt_build_tree(struct mount_info *list)
{
struct mount_info *tree;
@@ -208,6 +253,8 @@ static struct mount_info *mnt_build_tree(struct mount_info *list)
return NULL;
mnt_resort_siblings(tree);
+ if (collect_shared(list))
+ return NULL;
pr_info("Done:\n");
mnt_tree_show(tree, 0);
return tree;
@@ -457,36 +504,6 @@ static struct fstype *decode_fstype(u32 fst)
return &fstypes[fst];
}
-static int validate_shared(struct mount_info *info)
-{
- struct mount_info *m, *t;
-
- /*
- * If we have a shared mounts, both master
- * slave targets are to be present in mount
- * list, otherwise we can't be sure if we can
- * recreate the scheme later on restore.
- */
- for (m = info; m; m = m->next) {
- if (!m->master_id)
- continue;
-
- for (t = info; t; t = t->next) {
- if (t->shared_id == m->master_id)
- break;
- }
- if (t)
- continue;
-
- pr_err("Mount %d (master_id: %d shared_id: %d) "
- "has unreachable sharing\n", m->mnt_id,
- m->master_id, m->shared_id);
- return -1;
- }
-
- return 0;
-}
-
static int dump_one_mountpoint(struct mount_info *pm, int fd)
{
MntEntry me = MNT_ENTRY__INIT;
@@ -533,11 +550,6 @@ int dump_mnt_ns(int ns_pid, struct cr_fdset *fdset)
if (mnt_build_tree(pm) == NULL)
return -1;
- if (validate_shared(mntinfo)) {
- pr_err("Can't proceed %d's mountinfo\n", ns_pid);
- return -1;
- }
-
pr_info("Dumping mountpoints\n");
img_fd = fdset_fd(fdset, CR_FD_MNTS);
@@ -747,6 +759,9 @@ struct mount_info *mnt_entry_alloc()
if (new) {
INIT_LIST_HEAD(&new->children);
INIT_LIST_HEAD(&new->siblings);
+ INIT_LIST_HEAD(&new->mnt_slave_list);
+ INIT_LIST_HEAD(&new->mnt_share);
+ new->mnt_master = NULL;
}
return new;
}
--
1.8.3.1
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