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authorSage Weil <sage@newdream.net>2011-02-05 05:45:58 +0100
committerSage Weil <sage@newdream.net>2011-02-05 05:45:58 +0100
commite8e1ba96b207deba1339b09983f8b29f92cb1497 (patch)
tree281f255e549ec247699d9860117c3b684c472997
parentlibceph: fix socket write error handling (diff)
downloadlinux-e8e1ba96b207deba1339b09983f8b29f92cb1497.tar.xz
linux-e8e1ba96b207deba1339b09983f8b29f92cb1497.zip
ceph: queue cap_snaps once per realm
We were forming a dirty list, and then queueing cap_snaps for each realm _and_ its children, regardless of whether the children were already in the dirty list. This meant we did it twice for some realms. Which in turn meant we corrupted mdsc->snap_flush_list when the cap_snap was re-added to the list it was already on, and could trigger an infinite loop. We were also using recursion to do reach all the children, a no-no when stack is limited. Instead, (re)queue any children on the dirty list, avoiding processing anything twice and avoiding any recursion. Signed-off-by: Sage Weil <sage@newdream.net>
-rw-r--r--fs/ceph/snap.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 39c243acd062..f40b9139e437 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -584,10 +584,14 @@ static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
if (lastinode)
iput(lastinode);
- dout("queue_realm_cap_snaps %p %llx children\n", realm, realm->ino);
- list_for_each_entry(child, &realm->children, child_item)
- queue_realm_cap_snaps(child);
+ list_for_each_entry(child, &realm->children, child_item) {
+ dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
+ realm, realm->ino, child, child->ino);
+ list_del_init(&child->dirty_item);
+ list_add(&child->dirty_item, &realm->dirty_item);
+ }
+ list_del_init(&realm->dirty_item);
dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
}
@@ -683,7 +687,9 @@ more:
* queue cap snaps _after_ we've built the new snap contexts,
* so that i_head_snapc can be set appropriately.
*/
- list_for_each_entry(realm, &dirty_realms, dirty_item) {
+ while (!list_empty(&dirty_realms)) {
+ realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
+ dirty_item);
queue_realm_cap_snaps(realm);
}