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mount: allow overmount on parent with shared group

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In CT, we do:

mkdir -p /a/b/c1
mkdir -p /c2
mount --bind /c2 /a/b/c1
mount --rbind /a/b /a

And after that container is not dumpable with error:

mnt: Unable to handle mounts under 146:./a

Just because overmounts with shared parent group are prohibited,
but I can't see any problem with enabling them.

https://jira.sw.ru/browse/PSBM-69501
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Pavel Tikhomirov
2017-10-20 10:24:28 +03:00
committed by Andrei Vagin
parent 2214568de9
commit bf1f9c61c1
1 changed files with 11 additions and 9 deletions
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20
criu/mount.c
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@@ -688,7 +688,7 @@ static int validate_mounts(struct mount_info *info, bool for_dump)
return -1;
if (mnt_is_external(m))
goto skip_fstype;
continue;
/*
* Mountpoint can point to / of an FS. In that case this FS
@@ -738,13 +738,6 @@ static int validate_mounts(struct mount_info *info, bool for_dump)
}
}
}
skip_fstype:
if (does_mnt_overmount(m) &&
!list_empty(&m->parent->mnt_share)) {
pr_err("Unable to handle mounts under %d:%s\n",
m->mnt_id, m->mountpoint);
return -1;
}
}
return 0;
@@ -1685,12 +1678,21 @@ static int propagate_mount(struct mount_info *mi)
char path[PATH_MAX], *mp;
bool found = false;
/*
* If a mount from parent's shared group is not yet mounted
* it shouldn't have 'sibling' in it - see can_mount_now()
*/
if (!t->mounted)
continue;
mp = mnt_get_sibling_path(mi, t, path, sizeof(path));
if (mp == NULL)
continue;
list_for_each_entry(c, &t->children, siblings) {
if (mounts_equal(mi, c) && !strcmp(mp, c->mountpoint)) {
/* Should not propagate the same mount twice */
BUG_ON(c->mounted);
pr_debug("\t\tPropagate %s\n", c->mountpoint);
/*
@@ -2287,7 +2289,7 @@ static int try_remap_mount(struct mount_info *m)
if (!does_mnt_overmount(m))
return 0;
BUG_ON(!m->parent || !list_empty(&m->parent->mnt_share));
BUG_ON(!m->parent);
r = xmalloc(sizeof(struct mnt_remap_entry));
if (!r)