diff options
| -rw-r--r-- | fs/nfs/dir.c | 43 | ||||
| -rw-r--r-- | include/linux/nfs_fs.h | 1 |
2 files changed, 42 insertions, 2 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 2bfbde0f7176..1b5f38f48dab 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -2079,7 +2079,7 @@ 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_rpccred(entry->cred); - kfree(entry); + kfree_rcu(entry, rcu_head); smp_mb__before_atomic(); atomic_long_dec(&nfs_access_nr_entries); smp_mb__after_atomic(); @@ -2257,6 +2257,38 @@ out_zap: return -ENOENT; } +static int nfs_access_get_cached_rcu(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) +{ + /* Only check the most recently returned cache entry, + * but do it without locking. + */ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_access_entry *cache; + int err = -ECHILD; + struct list_head *lh; + + rcu_read_lock(); + if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) + goto out; + lh = rcu_dereference(nfsi->access_cache_entry_lru.prev); + cache = list_entry(lh, struct nfs_access_entry, lru); + if (lh == &nfsi->access_cache_entry_lru || + cred != cache->cred) + cache = NULL; + if (cache == NULL) + goto out; + if (!nfs_have_delegated_attributes(inode) && + !time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo)) + goto out; + res->jiffies = cache->jiffies; + res->cred = cache->cred; + res->mask = cache->mask; + err = 0; +out: + rcu_read_unlock(); + return err; +} + static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) { struct nfs_inode *nfsi = NFS_I(inode); @@ -2300,6 +2332,11 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) cache->cred = get_rpccred(set->cred); cache->mask = set->mask; + /* The above field assignments must be visible + * before this item appears on the lru. We cannot easily + * use rcu_assign_pointer, so just force the memory barrier. + */ + smp_wmb(); nfs_access_add_rbtree(inode, cache); /* Update accounting */ @@ -2339,7 +2376,9 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) trace_nfs_access_enter(inode); - status = nfs_access_get_cached(inode, cred, &cache); + status = nfs_access_get_cached_rcu(inode, cred, &cache); + if (status != 0) + status = nfs_access_get_cached(inode, cred, &cache); if (status == 0) goto out_cached; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 60cd9e377926..5180a7ededec 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -52,6 +52,7 @@ struct nfs_access_entry { unsigned long jiffies; struct rpc_cred * cred; int mask; + struct rcu_head rcu_head; }; struct nfs_lockowner { |