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[PATCH] knfsd: nfsd4: limit number of delegations handed out.

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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 <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
NeilBrown 2006-04-10 22:55:41 -07:00 committed by Linus Torvalds
parent 4e2fd495b5
commit ef0f3390eb
1 changed files with 40 additions and 34 deletions
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74
fs/nfsd/nfs4state.c
View File

@ -147,6 +147,42 @@ get_nfs4_file(struct nfs4_file *fi)
kref_get(&fi->fi_ref);
}
static int num_delegations;
/*
* 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 +191,12 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
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 +231,7 @@ nfs4_put_delegation(struct nfs4_delegation *dp)
dprintk("NFSD: freeing dp %p\n",dp);
put_nfs4_file(dp->dl_file);
kmem_cache_free(deleg_slab, dp);
num_delegations--;
}
}
@ -943,40 +983,6 @@ 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)