Btrfs: fix acl caching

[net-next-2.6.git] / fs / btrfs / acl.c

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 7fdd184a528d11caa58ddb37f8d59d07de17a517..cbba000dccbea147bb37cf85dd0ad688ec379238 100644 (file)
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -60,15 +60,20 @@ static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
                return ERR_PTR(-EINVAL);
        }
 
+       /* Handle the cached NULL acl case without locking */
+       acl = ACCESS_ONCE(*p_acl);
+       if (!acl)
+               return acl;
+
        spin_lock(&inode->i_lock);
-       if (*p_acl != BTRFS_ACL_NOT_CACHED)
-               acl = posix_acl_dup(*p_acl);
+       acl = *p_acl;
+       if (acl != BTRFS_ACL_NOT_CACHED)
+               acl = posix_acl_dup(acl);
        spin_unlock(&inode->i_lock);
 
-       if (acl)
+       if (acl != BTRFS_ACL_NOT_CACHED)
                return acl;
 
-
        size = __btrfs_getxattr(inode, name, "", 0);
        if (size > 0) {
                value = kzalloc(size, GFP_NOFS);
@@ -80,9 +85,12 @@ static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
                        btrfs_update_cached_acl(inode, p_acl, acl);
                }
                kfree(value);
-       } else if (size == -ENOENT) {
+       } else if (size == -ENOENT || size == -ENODATA || size == 0) {
+               /* FIXME, who returns -ENOENT?  I think nobody */
                acl = NULL;
                btrfs_update_cached_acl(inode, p_acl, acl);
+       } else {
+               acl = ERR_PTR(-EIO);
        }
 
        return acl;