diff options
| author | Christoph Hellwig <hch@infradead.org> | 2010-10-10 05:36:27 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-10-25 21:26:13 -0400 |
| commit | 3825bdb7ed920845961f32f364454bee5f469abb (patch) | |
| tree | 935f4d42ff568efd595700889a1839a604aa8cec /fs | |
| parent | a4633357ac610cd2f8740e28a31fc148a7960421 (diff) | |
fs: use RCU read side protection in d_validate
d_validate does a purely read lookup in the dentry hash, so use RCU read side
locking instead of dcache_lock. Split out from a larget patch by
Nick Piggin <npiggin@suse.de>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/dcache.c | 31 |
1 files changed, 12 insertions, 19 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index cc2b93802179..23702a9d4e6d 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1491,33 +1491,26 @@ out: * This is used by ncpfs in its readdir implementation. * Zero is returned in the dentry is invalid. */ - -int d_validate(struct dentry *dentry, struct dentry *dparent) +int d_validate(struct dentry *dentry, struct dentry *parent) { - struct hlist_head *base; - struct hlist_node *lhp; + struct hlist_head *head = d_hash(parent, dentry->d_name.hash); + struct hlist_node *node; + struct dentry *d; /* Check whether the ptr might be valid at all.. */ if (!kmem_ptr_validate(dentry_cache, dentry)) - goto out; - - if (dentry->d_parent != dparent) - goto out; + return 0; + if (dentry->d_parent != parent) + return 0; - spin_lock(&dcache_lock); - base = d_hash(dparent, dentry->d_name.hash); - hlist_for_each(lhp,base) { - /* hlist_for_each_entry_rcu() not required for d_hash list - * as it is parsed under dcache_lock - */ - if (dentry == hlist_entry(lhp, struct dentry, d_hash)) { - __dget_locked(dentry); - spin_unlock(&dcache_lock); + rcu_read_lock(); + hlist_for_each_entry_rcu(d, node, head, d_hash) { + if (d == dentry) { + dget(dentry); return 1; } } - spin_unlock(&dcache_lock); -out: + rcu_read_unlock(); return 0; } EXPORT_SYMBOL(d_validate); |