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 <[email protected]>
Signed-off-by: Neil Brown <[email protected]>
### Diffstat output
./fs/nfsd/nfs4state.c | 73 ++++++++++++++++++++++++++------------------------
1 file changed, 39 insertions(+), 34 deletions(-)
diff ./fs/nfsd/nfs4state.c~current~ ./fs/nfsd/nfs4state.c
--- ./fs/nfsd/nfs4state.c~current~ 2006-04-03 15:12:16.000000000 +1000
+++ ./fs/nfsd/nfs4state.c 2006-04-03 15:12:17.000000000 +1000
@@ -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--;
}
}
@@ -943,40 +982,6 @@ 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)
-
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