[PATCH AUTOSEL 4.19 57/68] NFSv4.2 copy do not allocate memory under the lock

From: Olga Kornievskaia kolga@netapp.com

[ Upstream commit 99f2c55591fb5c1b536263970d98c2ebc2089906 ]

Bruce pointed out that we shouldn't allocate memory while holding a lock in the nfs4_callback_offload() and handle_async_copy() that deal with a racing CB_OFFLOAD and reply to COPY case.

Signed-off-by: Olga Kornievskaia kolga@netapp.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/callback_proc.c | 22 +++++++++++----------- fs/nfs/nfs42proc.c | 19 ++++++++++--------- 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c index fa515d5ea5ba..48b2e9063b0a 100644 --- a/fs/nfs/callback_proc.c +++ b/fs/nfs/callback_proc.c @@ -686,20 +686,24 @@ __be32 nfs4_callback_offload(void *data, void *dummy, { struct cb_offloadargs *args = data; struct nfs_server *server; - struct nfs4_copy_state *copy; + struct nfs4_copy_state *copy, *tmp_copy; bool found = false;

+ copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS); + if (!copy) + return htonl(NFS4ERR_SERVERFAULT); + spin_lock(&cps->clp->cl_lock); rcu_read_lock(); list_for_each_entry_rcu(server, &cps->clp->cl_superblocks, client_link) { - list_for_each_entry(copy, &server->ss_copies, copies) { + list_for_each_entry(tmp_copy, &server->ss_copies, copies) { if (memcmp(args->coa_stateid.other, - copy->stateid.other, + tmp_copy->stateid.other, sizeof(args->coa_stateid.other))) continue; - nfs4_copy_cb_args(copy, args); - complete(&copy->completion); + nfs4_copy_cb_args(tmp_copy, args); + complete(&tmp_copy->completion); found = true; goto out; } @@ -707,15 +711,11 @@ __be32 nfs4_callback_offload(void *data, void *dummy, out: rcu_read_unlock(); if (!found) { - copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS); - if (!copy) { - spin_unlock(&cps->clp->cl_lock); - return htonl(NFS4ERR_SERVERFAULT); - } memcpy(&copy->stateid, &args->coa_stateid, NFS4_STATEID_SIZE); nfs4_copy_cb_args(copy, args); list_add_tail(&copy->copies, &cps->clp->pending_cb_stateids); - } + } else + kfree(copy); spin_unlock(&cps->clp->cl_lock);

return 0; diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c index ac5b784a1de0..fed06fd9998d 100644 --- a/fs/nfs/nfs42proc.c +++ b/fs/nfs/nfs42proc.c @@ -137,31 +137,32 @@ static int handle_async_copy(struct nfs42_copy_res *res, struct file *dst, nfs4_stateid *src_stateid) { - struct nfs4_copy_state *copy; + struct nfs4_copy_state *copy, *tmp_copy; int status = NFS4_OK; bool found_pending = false; struct nfs_open_context *ctx = nfs_file_open_context(dst);

+ copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS); + if (!copy) + return -ENOMEM; + spin_lock(&server->nfs_client->cl_lock); - list_for_each_entry(copy, &server->nfs_client->pending_cb_stateids, + list_for_each_entry(tmp_copy, &server->nfs_client->pending_cb_stateids, copies) { - if (memcmp(&res->write_res.stateid, &copy->stateid, + if (memcmp(&res->write_res.stateid, &tmp_copy->stateid, NFS4_STATEID_SIZE)) continue; found_pending = true; - list_del(&copy->copies); + list_del(&tmp_copy->copies); break; } if (found_pending) { spin_unlock(&server->nfs_client->cl_lock); + kfree(copy); + copy = tmp_copy; goto out; }

- copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS); - if (!copy) { - spin_unlock(&server->nfs_client->cl_lock); - return -ENOMEM; - } memcpy(&copy->stateid, &res->write_res.stateid, NFS4_STATEID_SIZE); init_completion(&copy->completion); copy->parent_state = ctx->state;