On Wed, Oct 2, 2024 at 10:08 PM Patrick Donnelly <batrick@xxxxxxxxxxxx> wrote:
>
> From: Patrick Donnelly <pdonnell@xxxxxxxxxx>
>
> Log recovered from a user's cluster:
>
> <7>[ 5413.970692] ceph: get_cap_refs 00000000958c114b ret 1 got Fr
> <7>[ 5413.970695] ceph: start_read 00000000958c114b, no cache cap
Hi Patrick,
Noting that start_read() was removed in kernel 5.13 in commit
49870056005c ("ceph: convert ceph_readpages to ceph_readahead").
> ...
> <7>[ 5473.934609] ceph: my wanted = Fr, used = Fr, dirty -
> <7>[ 5473.934616] ceph: revocation: pAsLsXsFr -> pAsLsXs (revoking Fr)
> <7>[ 5473.934632] ceph: __ceph_caps_issued 00000000958c114b cap 00000000f7784259 issued pAsLsXs
> <7>[ 5473.934638] ceph: check_caps 10000000e68.fffffffffffffffe file_want - used Fr dirty - flushing - issued pAsLsXs revoking Fr retain pAsLsXsFsr AUTHONLY NOINVAL FLUSH_FORCE
>
> The MDS subsequently complains that the kernel client is late releasing caps.
>
> Closes: https://tracker.ceph.com/issues/67008
> Fixes: a5c9dc4451394b2854493944dcc0ff71af9705a3 ("ceph: Make ceph_init_request() check caps on readahead")
I think it's worth going into a bit more detail here because
superficially this commit just replaced
ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want, true, &got);
if (ret < 0)
dout("start_read %p, error getting cap\n", inode);
else if (!(got & want))
dout("start_read %p, no cache cap\n", inode);
if (ret <= 0)
return;
in ceph_readahead() with
ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want, true, &got);
if (ret < 0) {
dout("start_read %p, error getting cap\n", inode);
return ret;
}
if (!(got & want)) {
dout("start_read %p, no cache cap\n", inode);
return -EACCES;
}
if (ret == 0)
return -EACCES;
in ceph_init_request(). Neither called ceph_put_cap_refs() before
bailing. It was commit 49870056005c ("ceph: convert ceph_readpages to
ceph_readahead") that turned a direct call to ceph_put_cap_refs() in
start_read() to one in ceph_readahead_cleanup() (later renamed to
ceph_netfs_free_request()).
The actual problem is that netfs_alloc_request() just frees rreq if
init_request() callout fails and ceph_netfs_free_request() is never
called, right? If so, I'd mention that explicitly and possibly also
reference commit 2de160417315 ("netfs: Change ->init_request() to
return an error code") which introduced that.
> Signed-off-by: Patrick Donnelly <pdonnell@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> fs/ceph/addr.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index 53fef258c2bc..702c6a730b70 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -489,8 +489,11 @@ static int ceph_init_request(struct netfs_io_request *rreq, struct file *file)
> rreq->io_streams[0].sreq_max_len = fsc->mount_options->rsize;
>
> out:
> - if (ret < 0)
> + if (ret < 0) {
> + if (got)
> + ceph_put_cap_refs(ceph_inode(inode), got);
> kfree(priv);
> + }
>
> return ret;
> }
The change itself looks fine. Great catch!
Thanks,
Ilya
