3.16.78-rc1 review patch. If anyone has any objections, please let me know.
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From: Trond Myklebust trond.myklebust@hammerspace.com
commit c77e22834ae9a11891cb613bd9a551be1b94f2bc upstream.
John Hubbard reports seeing the following stack trace:
nfs4_do_reclaim rcu_read_lock /* we are now in_atomic() and must not sleep */ nfs4_purge_state_owners nfs4_free_state_owner nfs4_destroy_seqid_counter rpc_destroy_wait_queue cancel_delayed_work_sync __cancel_work_timer __flush_work start_flush_work might_sleep: (kernel/workqueue.c:2975: BUG)
The solution is to separate out the freeing of the state owners from nfs4_purge_state_owners(), and perform that outside the atomic context.
Reported-by: John Hubbard jhubbard@nvidia.com Fixes: 0aaaf5c424c7f ("NFS: Cache state owners after files are closed") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/nfs/nfs4_fs.h | 3 ++- fs/nfs/nfs4client.c | 5 ++++- fs/nfs/nfs4state.c | 27 ++++++++++++++++++++++----- 3 files changed, 28 insertions(+), 7 deletions(-)
--- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -419,7 +419,8 @@ static inline void nfs4_schedule_session
extern struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *, struct rpc_cred *, gfp_t); extern void nfs4_put_state_owner(struct nfs4_state_owner *); -extern void nfs4_purge_state_owners(struct nfs_server *); +extern void nfs4_purge_state_owners(struct nfs_server *, struct list_head *); +extern void nfs4_free_state_owners(struct list_head *head); extern struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state_owner *); extern void nfs4_put_open_state(struct nfs4_state *); extern void nfs4_close_state(struct nfs4_state *, fmode_t); --- a/fs/nfs/nfs4client.c +++ b/fs/nfs/nfs4client.c @@ -682,9 +682,12 @@ int nfs41_walk_client_list(struct nfs_cl
static void nfs4_destroy_server(struct nfs_server *server) { + LIST_HEAD(freeme); + nfs_server_return_all_delegations(server); unset_pnfs_layoutdriver(server); - nfs4_purge_state_owners(server); + nfs4_purge_state_owners(server, &freeme); + nfs4_free_state_owners(&freeme); }
/* --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -598,24 +598,39 @@ void nfs4_put_state_owner(struct nfs4_st /** * nfs4_purge_state_owners - Release all cached state owners * @server: nfs_server with cached state owners to release + * @head: resulting list of state owners * * Called at umount time. Remaining state owners will be on * the LRU with ref count of zero. + * Note that the state owners are not freed, but are added + * to the list @head, which can later be used as an argument + * to nfs4_free_state_owners. */ -void nfs4_purge_state_owners(struct nfs_server *server) +void nfs4_purge_state_owners(struct nfs_server *server, struct list_head *head) { struct nfs_client *clp = server->nfs_client; struct nfs4_state_owner *sp, *tmp; - LIST_HEAD(doomed);
spin_lock(&clp->cl_lock); list_for_each_entry_safe(sp, tmp, &server->state_owners_lru, so_lru) { - list_move(&sp->so_lru, &doomed); + list_move(&sp->so_lru, head); nfs4_remove_state_owner_locked(sp); } spin_unlock(&clp->cl_lock); +} + +/** + * nfs4_purge_state_owners - Release all cached state owners + * @head: resulting list of state owners + * + * Frees a list of state owners that was generated by + * nfs4_purge_state_owners + */ +void nfs4_free_state_owners(struct list_head *head) +{ + struct nfs4_state_owner *sp, *tmp;
- list_for_each_entry_safe(sp, tmp, &doomed, so_lru) { + list_for_each_entry_safe(sp, tmp, head, so_lru) { list_del(&sp->so_lru); nfs4_free_state_owner(sp); } @@ -1719,12 +1734,13 @@ static int nfs4_do_reclaim(struct nfs_cl struct nfs4_state_owner *sp; struct nfs_server *server; struct rb_node *pos; + LIST_HEAD(freeme); int status = 0;
restart: rcu_read_lock(); list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { - nfs4_purge_state_owners(server); + nfs4_purge_state_owners(server, &freeme); spin_lock(&clp->cl_lock); for (pos = rb_first(&server->state_owners); pos != NULL; @@ -1752,6 +1768,7 @@ restart: spin_unlock(&clp->cl_lock); } rcu_read_unlock(); + nfs4_free_state_owners(&freeme); return 0; }