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authorXiubo Li <xiubli@redhat.com>2021-08-18 21:38:42 +0800
committerIlya Dryomov <idryomov@gmail.com>2021-08-25 16:34:11 +0200
commitb2f9fa1f3bd8846f50b355fc2168236975c4d264 (patch)
treee0aee74a8b50c39d3628a9d772911b740e8fbcbb
parente22ce8eb631bdc47a4a4ea7ecf4e4ba499db4f93 (diff)
ceph: correctly handle releasing an embedded cap flush
The ceph_cap_flush structures are usually dynamically allocated, but the ceph_cap_snap has an embedded one. When force umounting, the client will try to remove all the session caps. During this, it will free them, but that should not be done with the ones embedded in a capsnap. Fix this by adding a new boolean that indicates that the cap flush is embedded in a capsnap, and skip freeing it if that's set. At the same time, switch to using list_del_init() when detaching the i_list and g_list heads. It's possible for a forced umount to remove these objects but then handle_cap_flushsnap_ack() races in and does the list_del_init() again, corrupting memory. Cc: stable@vger.kernel.org URL: https://tracker.ceph.com/issues/52283 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
-rw-r--r--fs/ceph/caps.c21
-rw-r--r--fs/ceph/mds_client.c7
-rw-r--r--fs/ceph/snap.c3
-rw-r--r--fs/ceph/super.h3
4 files changed, 22 insertions, 12 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 2a2900903f8c..39db97f149b9 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1743,7 +1743,11 @@ int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask,
struct ceph_cap_flush *ceph_alloc_cap_flush(void)
{
- return kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
+ struct ceph_cap_flush *cf;
+
+ cf = kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
+ cf->is_capsnap = false;
+ return cf;
}
void ceph_free_cap_flush(struct ceph_cap_flush *cf)
@@ -1778,7 +1782,7 @@ static bool __detach_cap_flush_from_mdsc(struct ceph_mds_client *mdsc,
prev->wake = true;
wake = false;
}
- list_del(&cf->g_list);
+ list_del_init(&cf->g_list);
return wake;
}
@@ -1793,7 +1797,7 @@ static bool __detach_cap_flush_from_ci(struct ceph_inode_info *ci,
prev->wake = true;
wake = false;
}
- list_del(&cf->i_list);
+ list_del_init(&cf->i_list);
return wake;
}
@@ -2352,7 +2356,7 @@ static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
list_for_each_entry_reverse(cf, &ci->i_cap_flush_list, i_list) {
- if (!cf->caps) {
+ if (cf->is_capsnap) {
last_snap_flush = cf->tid;
break;
}
@@ -2371,7 +2375,7 @@ static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
first_tid = cf->tid + 1;
- if (cf->caps) {
+ if (!cf->is_capsnap) {
struct cap_msg_args arg;
dout("kick_flushing_caps %p cap %p tid %llu %s\n",
@@ -3516,7 +3520,7 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
cleaned = cf->caps;
/* Is this a capsnap? */
- if (cf->caps == 0)
+ if (cf->is_capsnap)
continue;
if (cf->tid <= flush_tid) {
@@ -3589,8 +3593,9 @@ out:
while (!list_empty(&to_remove)) {
cf = list_first_entry(&to_remove,
struct ceph_cap_flush, i_list);
- list_del(&cf->i_list);
- ceph_free_cap_flush(cf);
+ list_del_init(&cf->i_list);
+ if (!cf->is_capsnap)
+ ceph_free_cap_flush(cf);
}
if (wake_ci)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index afdc20213876..0b69aec23e5c 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1616,7 +1616,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
spin_lock(&mdsc->cap_dirty_lock);
list_for_each_entry(cf, &to_remove, i_list)
- list_del(&cf->g_list);
+ list_del_init(&cf->g_list);
if (!list_empty(&ci->i_dirty_item)) {
pr_warn_ratelimited(
@@ -1668,8 +1668,9 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
struct ceph_cap_flush *cf;
cf = list_first_entry(&to_remove,
struct ceph_cap_flush, i_list);
- list_del(&cf->i_list);
- ceph_free_cap_flush(cf);
+ list_del_init(&cf->i_list);
+ if (!cf->is_capsnap)
+ ceph_free_cap_flush(cf);
}
wake_up_all(&ci->i_cap_wq);
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 4c6bd1042c94..15105f9da3fd 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -487,6 +487,9 @@ static void ceph_queue_cap_snap(struct ceph_inode_info *ci)
pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
return;
}
+ capsnap->cap_flush.is_capsnap = true;
+ INIT_LIST_HEAD(&capsnap->cap_flush.i_list);
+ INIT_LIST_HEAD(&capsnap->cap_flush.g_list);
spin_lock(&ci->i_ceph_lock);
used = __ceph_caps_used(ci);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 9215a2f4535c..b1a363641beb 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -182,8 +182,9 @@ struct ceph_cap {
struct ceph_cap_flush {
u64 tid;
- int caps; /* 0 means capsnap */
+ int caps;
bool wake; /* wake up flush waiters when finish ? */
+ bool is_capsnap; /* true means capsnap */
struct list_head g_list; // global
struct list_head i_list; // per inode
};