Re: [PATCH 1/3] ceph: remove the capsnaps when removing the caps

[Xiubo Li <xiubli@redhat.com>]

On 8/23/21 10:58 PM, Jeff Layton wrote:
> On Wed, 2021-08-18 at 16:06 +0800, xiubli@redhat.com wrote:
>> From: Xiubo Li <xiubli@redhat.com>
>>
>> The capsnaps will ihold the inodes when queuing to flush, so when
>> force umounting it will close the sessions first and if the MDSes
>> respond very fast and the session connections are closed just
>> before killing the superblock, which will flush the msgr queue,
>> then the flush capsnap callback won't ever be called, which will
>> lead the memory leak bug for the ceph_inode_info.
>>
>> URL: https://tracker.ceph.com/issues/52295
>> Signed-off-by: Xiubo Li <xiubli@redhat.com>
>> ---
>>   fs/ceph/caps.c       | 47 +++++++++++++++++++++++++++++---------------
>>   fs/ceph/mds_client.c | 23 +++++++++++++++++++++-
>>   fs/ceph/super.h      |  3 +++
>>   3 files changed, 56 insertions(+), 17 deletions(-)
>>
>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
>> index e239f06babbc..7def99fbdca6 100644
>> --- a/fs/ceph/caps.c
>> +++ b/fs/ceph/caps.c
>> @@ -3663,6 +3663,34 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
>>   		iput(inode);
>>   }
>>   
>> +/*
>> + * Caller hold s_mutex and i_ceph_lock.
>> + */
>> +void ceph_remove_capsnap(struct inode *inode, struct ceph_cap_snap *capsnap,
>> +			 bool *wake_ci, bool *wake_mdsc)
>> +{
>> +	struct ceph_inode_info *ci = ceph_inode(inode);
>> +	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
>> +	bool ret;
>> +
>> +	dout("removing capsnap %p, inode %p ci %p\n", capsnap, inode, ci);
>> +
>> +	WARN_ON(capsnap->dirty_pages || capsnap->writing);
> Can we make this a WARN_ON_ONCE too?

Yeah, will fix it.

Thanks