[PATCH v17 13/22] vfs: Cache richacl in struct inode

Andreas Gruenbacher
2016-01-11T15:23:32Z

Cache richacls in struct inode so that this doesn't have to be done
individually in each filesystem. This is similar to POSIX ACLs.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/inode.c | 11 +++++--
fs/posix_acl.c | 2 +-
fs/richacl_inode.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 5 +++-
include/linux/richacl.h | 6 ++++
5 files changed, 96 insertions(+), 5 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 1d6d035..3459bc9 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -174,8 +174,11 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_private = NULL;
inode->i_mapping = mapping;
INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
-#ifdef CONFIG_FS_POSIX_ACL
- inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
+ inode->i_acl = ACL_NOT_CACHED;
+# if defined(CONFIG_FS_POSIX_ACL)
+ inode->i_default_acl = ACL_NOT_CACHED;
+# endif
#endif

#ifdef CONFIG_FSNOTIFY
@@ -231,11 +234,13 @@ void __destroy_inode(struct inode *inode)
atomic_long_dec(&inode->i_sb->s_remove_count);
}

-#ifdef CONFIG_FS_POSIX_ACL
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
base_acl_put(inode->i_acl);
+# if defined(CONFIG_FS_POSIX_ACL)
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
base_acl_put(inode->i_default_acl);
+# endif
#endif
this_cpu_dec(nr_inodes);
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 743b6dc..f24646e 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -37,7 +37,7 @@ struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
struct base_acl **p = acl_by_type(inode, type);
struct base_acl *acl = ACCESS_ONCE(*p);
- if (acl) {
+ if (acl && IS_POSIXACL(inode)) {
spin_lock(&inode->i_lock);
acl = *p;
if (acl != ACL_NOT_CACHED)
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 99b3c93..52c1595 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -20,6 +20,83 @@
#include <linux/slab.h>
#include <linux/richacl.h>

+struct richacl *get_cached_richacl(struct inode *inode)
+{
+ struct base_acl *acl;
+
+ acl = ACCESS_ONCE(inode->i_acl);
+ if (acl && IS_RICHACL(inode)) {
+ spin_lock(&inode->i_lock);
+ acl = inode->i_acl;
+ if (acl != ACL_NOT_CACHED)
+ base_acl_get(acl);
+ spin_unlock(&inode->i_lock);
+ }
+ return container_of(acl, struct richacl, a_base);
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl);
+
+struct richacl *get_cached_richacl_rcu(struct inode *inode)
+{
+ struct base_acl *acl = rcu_dereference(inode->i_acl);
+
+ return container_of(acl, struct richacl, a_base);
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl_rcu);
+
+void set_cached_richacl(struct inode *inode, struct richacl *acl)
+{
+ struct base_acl *old = NULL;
+
+ spin_lock(&inode->i_lock);
+ old = inode->i_acl;
+ rcu_assign_pointer(inode->i_acl, &richacl_get(acl)->a_base);
+ spin_unlock(&inode->i_lock);
+ if (old != ACL_NOT_CACHED)
+ base_acl_put(old);
+}
+EXPORT_SYMBOL_GPL(set_cached_richacl);
+
+void forget_cached_richacl(struct inode *inode)
+{
+ struct base_acl *old = NULL;
+
+ spin_lock(&inode->i_lock);
+ old = inode->i_acl;
+ inode->i_acl = ACL_NOT_CACHED;
+ spin_unlock(&inode->i_lock);
+ if (old != ACL_NOT_CACHED)
+ base_acl_put(old);
+}
+EXPORT_SYMBOL_GPL(forget_cached_richacl);
+
+struct richacl *get_richacl(struct inode *inode)
+{
+ struct richacl *acl;
+
+ acl = get_cached_richacl(inode);
+ if (acl != ACL_NOT_CACHED)
+ return acl;
+
+ if (!IS_RICHACL(inode))
+ return NULL;
+
+ /*
+ * A filesystem can force a ACL callback by just never filling the
+ * ACL cache. But normally you'd fill the cache either at inode
+ * instantiation time, or on the first ->get_richacl call.
+ *
+ * If the filesystem doesn't have a get_richacl() function at all,
+ * we'll just create the negative cache entry.
+ */
+ if (!inode->i_op->get_richacl) {
+ set_cached_richacl(inode, NULL);
+ return NULL;
+ }
+ return inode->i_op->get_richacl(inode);
+}
+EXPORT_SYMBOL_GPL(get_richacl);
+
/**
* richacl_permission - richacl permission check algorithm
* @inode: inode to check
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4847417..76d71b2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -583,6 +583,7 @@ struct base_acl {
};
};
struct posix_acl;
+struct richacl;
#define ACL_NOT_CACHED ((void *)(-1))

#define IOP_FASTPERM 0x0001
@@ -601,9 +602,11 @@ struct inode {
kgid_t i_gid;
unsigned int i_flags;

-#if defined(CONFIG_FS_POSIX_ACL)
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
struct base_acl *i_acl;
+# if defined(CONFIG_FS_POSIX_ACL)
struct base_acl *i_default_acl;
+# endif
#endif

const struct inode_operations *i_op;
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 7628fad..7bf912b6 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -70,6 +70,12 @@ richacl_put(struct richacl *acl)
base_acl_put(&acl->a_base);
}

+extern struct richacl *get_cached_richacl(struct inode *);
+extern struct richacl *get_cached_richacl_rcu(struct inode *);
+extern void set_cached_richacl(struct inode *, struct richacl *);
+extern void forget_cached_richacl(struct inode *);
+extern struct richacl *get_richacl(struct inode *);
+
/**
* richace_is_owner - check if @ace is an OWNER@ entry
*/