[PATCH 5.15 091/244] ceph: dont leak snap_rwsem in handle_cap_grant

Greg Kroah-Hartman
2022-08-23T09:59:49Z

From: Jeff Layton <jlayton@kernel.org>

commit 58dd4385577ed7969b80cdc9e2a31575aba6c712 upstream.

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.

Fixes: 6f05b30ea063 ("ceph: reset i_requested_max_size if file write is not wanted")
Link: https://tracker.ceph.com/issues/55857
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luís Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ceph/caps.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)

--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3543,24 +3543,23 @@ static void handle_cap_grant(struct inod
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);
- spin_unlock(&ci->i_ceph_lock);
+ ceph_kick_flushing_inode_caps(session, ci);
+ }
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,