On 6/4/22 4:39 AM, Jeff Layton wrote:
When handle_cap_grant is called on an IMPORT op, then the snap_rwsem is
held and the function is expected to release it before returning. It
currently fails to do that in all cases which could lead to a deadlock.
URL: https://tracker.ceph.com/issues/55857
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/ceph/caps.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 258093e9074d..0a48bf829671 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3579,24 +3579,23 @@ static void handle_cap_grant(struct inode *inode,
fill_inline = true;
}
- if (ci->i_auth_cap == cap &&
- le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
- if (newcaps & ~extra_info->issued)
- wake = true;
+ if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
+ if (ci->i_auth_cap == cap) {
+ if (newcaps & ~extra_info->issued)
+ wake = true;
+
+ if (ci->i_requested_max_size > max_size ||
+ !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) {
+ /* re-request max_size if necessary */
+ ci->i_requested_max_size = 0;
+ wake = true;
+ }
- if (ci->i_requested_max_size > max_size ||
- !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) {
- /* re-request max_size if necessary */
- ci->i_requested_max_size = 0;
- wake = true;
+ ceph_kick_flushing_inode_caps(session, ci);
}
-
- ceph_kick_flushing_inode_caps(session, ci);
- spin_unlock(&ci->i_ceph_lock);
up_read(&session->s_mdsc->snap_rwsem);
- } else {
- spin_unlock(&ci->i_ceph_lock);
}
+ spin_unlock(&ci->i_ceph_lock);
if (fill_inline)
ceph_fill_inline_data(inode, NULL, extra_info->inline_data,
I am not sure what the following code in Line#4139 wants to do, more
detail please see [1].
4131 if (msg_version >= 3) {
4132 if (op == CEPH_CAP_OP_IMPORT) {
4133 if (p + sizeof(*peer) > end)
4134 goto bad;
4135 peer = p;
4136 p += sizeof(*peer);
4137 } else if (op == CEPH_CAP_OP_EXPORT) {
4138 /* recorded in unused fields */
4139 peer = (void *)&h->size;
4140 }
4141 }
For the export case the members in the 'peer' are always assigned to
'random' values. And seems could cause this issue.
[1] https://github.com/ceph/ceph-client/blob/for-linus/fs/ceph/caps.c#L4134
I am still reading the code. Any idea ?
-- Xiubo
