From: NeilBrown It's very easy for the server to DOS itself by just giving out too many delegations. For now we just solve the problem with a dumb hard limit. Eventually we'll want a smarter policy. Signed-off-by: J. Bruce Fields Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- fs/nfsd/nfs4state.c | 73 ++++++++++++++++++++++-------------------- 1 files changed, 39 insertions(+), 34 deletions(-) diff -puN fs/nfsd/nfs4state.c~knfsd-nfsd4-limit-number-of-delegations-handed-out fs/nfsd/nfs4state.c --- 25/fs/nfsd/nfs4state.c~knfsd-nfsd4-limit-number-of-delegations-handed-out Mon Apr 3 16:08:21 2006 +++ 25-akpm/fs/nfsd/nfs4state.c Mon Apr 3 16:08:22 2006 @@ -147,6 +147,41 @@ get_nfs4_file(struct nfs4_file *fi) kref_get(&fi->fi_ref); } +int num_delegations = 0; +/* + * Open owner state (share locks) + */ + +/* hash tables for nfs4_stateowner */ +#define OWNER_HASH_BITS 8 +#define OWNER_HASH_SIZE (1 << OWNER_HASH_BITS) +#define OWNER_HASH_MASK (OWNER_HASH_SIZE - 1) + +#define ownerid_hashval(id) \ + ((id) & OWNER_HASH_MASK) +#define ownerstr_hashval(clientid, ownername) \ + (((clientid) + opaque_hashval((ownername.data), (ownername.len))) & OWNER_HASH_MASK) + +static struct list_head ownerid_hashtbl[OWNER_HASH_SIZE]; +static struct list_head ownerstr_hashtbl[OWNER_HASH_SIZE]; + +/* hash table for nfs4_file */ +#define FILE_HASH_BITS 8 +#define FILE_HASH_SIZE (1 << FILE_HASH_BITS) +#define FILE_HASH_MASK (FILE_HASH_SIZE - 1) +/* hash table for (open)nfs4_stateid */ +#define STATEID_HASH_BITS 10 +#define STATEID_HASH_SIZE (1 << STATEID_HASH_BITS) +#define STATEID_HASH_MASK (STATEID_HASH_SIZE - 1) + +#define file_hashval(x) \ + hash_ptr(x, FILE_HASH_BITS) +#define stateid_hashval(owner_id, file_id) \ + (((owner_id) + (file_id)) & STATEID_HASH_MASK) + +static struct list_head file_hashtbl[FILE_HASH_SIZE]; +static struct list_head stateid_hashtbl[STATEID_HASH_SIZE]; + static struct nfs4_delegation * alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_fh *current_fh, u32 type) { @@ -155,9 +190,12 @@ alloc_init_deleg(struct nfs4_client *clp struct nfs4_callback *cb = &stp->st_stateowner->so_client->cl_callback; dprintk("NFSD alloc_init_deleg\n"); + if (num_delegations > STATEID_HASH_SIZE * 4) + return NULL; dp = kmem_cache_alloc(deleg_slab, GFP_KERNEL); if (dp == NULL) return dp; + num_delegations++; INIT_LIST_HEAD(&dp->dl_perfile); INIT_LIST_HEAD(&dp->dl_perclnt); INIT_LIST_HEAD(&dp->dl_recall_lru); @@ -192,6 +230,7 @@ nfs4_put_delegation(struct nfs4_delegati dprintk("NFSD: freeing dp %p\n",dp); put_nfs4_file(dp->dl_file); kmem_cache_free(deleg_slab, dp); + num_delegations--; } } @@ -942,40 +981,6 @@ out: return status; } -/* - * Open owner state (share locks) - */ - -/* hash tables for nfs4_stateowner */ -#define OWNER_HASH_BITS 8 -#define OWNER_HASH_SIZE (1 << OWNER_HASH_BITS) -#define OWNER_HASH_MASK (OWNER_HASH_SIZE - 1) - -#define ownerid_hashval(id) \ - ((id) & OWNER_HASH_MASK) -#define ownerstr_hashval(clientid, ownername) \ - (((clientid) + opaque_hashval((ownername.data), (ownername.len))) & OWNER_HASH_MASK) - -static struct list_head ownerid_hashtbl[OWNER_HASH_SIZE]; -static struct list_head ownerstr_hashtbl[OWNER_HASH_SIZE]; - -/* hash table for nfs4_file */ -#define FILE_HASH_BITS 8 -#define FILE_HASH_SIZE (1 << FILE_HASH_BITS) -#define FILE_HASH_MASK (FILE_HASH_SIZE - 1) -/* hash table for (open)nfs4_stateid */ -#define STATEID_HASH_BITS 10 -#define STATEID_HASH_SIZE (1 << STATEID_HASH_BITS) -#define STATEID_HASH_MASK (STATEID_HASH_SIZE - 1) - -#define file_hashval(x) \ - hash_ptr(x, FILE_HASH_BITS) -#define stateid_hashval(owner_id, file_id) \ - (((owner_id) + (file_id)) & STATEID_HASH_MASK) - -static struct list_head file_hashtbl[FILE_HASH_SIZE]; -static struct list_head stateid_hashtbl[STATEID_HASH_SIZE]; - /* OPEN Share state helper functions */ static inline struct nfs4_file * alloc_init_file(struct inode *ino) _