NFS: don't store 'struct cred *' in struct nfs_access_entry
Storing the 'struct cred *' in nfs_access_entry is problematic.
An active 'cred' can keep a 'struct key *' active, and a quota is
imposed on the number of such keys that a user can maintain.
Cached 'nfs_access_entry' structs have indefinite lifetime, and having
these keep 'struct key's alive imposes on that quota.
So remove the 'struct cred *' and replace it with the fields we need:
kuid_t, kgid_t, and struct group_info *
This makes the 'struct nfs_access_entry' 64 bits larger.
New function "access_cmp" is introduced which is identical to
cred_fscmp() except that the second arg is an 'nfs_access_entry', rather
than a 'cred'
Fixes: b68572e07c58 ("NFS: change access cache to use 'struct cred'.")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a34351c..7dee3fd 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2528,7 +2528,7 @@ MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache lengt
static void nfs_access_free_entry(struct nfs_access_entry *entry)
{
- put_cred(entry->cred);
+ put_group_info(entry->group_info);
kfree_rcu(entry, rcu_head);
smp_mb__before_atomic();
atomic_long_dec(&nfs_access_nr_entries);
@@ -2654,6 +2654,43 @@ void nfs_access_zap_cache(struct inode *inode)
}
EXPORT_SYMBOL_GPL(nfs_access_zap_cache);
+static int access_cmp(const struct cred *a, const struct nfs_access_entry *b)
+{
+ struct group_info *ga, *gb;
+ int g;
+
+ if (uid_lt(a->fsuid, b->fsuid))
+ return -1;
+ if (uid_gt(a->fsuid, b->fsuid))
+ return 1;
+
+ if (gid_lt(a->fsgid, b->fsgid))
+ return -1;
+ if (gid_gt(a->fsgid, b->fsgid))
+ return 1;
+
+ ga = a->group_info;
+ gb = b->group_info;
+ if (ga == gb)
+ return 0;
+ if (ga == NULL)
+ return -1;
+ if (gb == NULL)
+ return 1;
+ if (ga->ngroups < gb->ngroups)
+ return -1;
+ if (ga->ngroups > gb->ngroups)
+ return 1;
+
+ for (g = 0; g < ga->ngroups; g++) {
+ if (gid_lt(ga->gid[g], gb->gid[g]))
+ return -1;
+ if (gid_gt(ga->gid[g], gb->gid[g]))
+ return 1;
+ }
+ return 0;
+}
+
static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred)
{
struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
@@ -2661,7 +2698,7 @@ static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, co
while (n != NULL) {
struct nfs_access_entry *entry =
rb_entry(n, struct nfs_access_entry, rb_node);
- int cmp = cred_fscmp(cred, entry->cred);
+ int cmp = access_cmp(cred, entry);
if (cmp < 0)
n = n->rb_left;
@@ -2731,7 +2768,7 @@ static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cre
lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru));
cache = list_entry(lh, struct nfs_access_entry, lru);
if (lh == &nfsi->access_cache_entry_lru ||
- cred_fscmp(cred, cache->cred) != 0)
+ access_cmp(cred, cache) != 0)
cache = NULL;
if (cache == NULL)
goto out;
@@ -2773,7 +2810,7 @@ static void nfs_access_add_rbtree(struct inode *inode,
while (*p != NULL) {
parent = *p;
entry = rb_entry(parent, struct nfs_access_entry, rb_node);
- cmp = cred_fscmp(cred, entry->cred);
+ cmp = access_cmp(cred, entry);
if (cmp < 0)
p = &parent->rb_left;
@@ -2802,7 +2839,9 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set,
if (cache == NULL)
return;
RB_CLEAR_NODE(&cache->rb_node);
- cache->cred = get_cred(cred);
+ cache->fsuid = cred->fsuid;
+ cache->fsgid = cred->fsgid;
+ cache->group_info = get_group_info(cred->group_info);
cache->mask = set->mask;
/* The above field assignments must be visible
@@ -2895,7 +2934,6 @@ static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask)
cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
else
cache.mask |= NFS_ACCESS_EXECUTE;
- cache.cred = cred;
status = NFS_PROTO(inode)->access(inode, &cache, cred);
if (status != 0) {
if (status == -ESTALE) {