[PATCH v10 12/46] vfs: Cache richacl in struct inode

Andreas Gruenbacher
2015-10-11T23:00:36Z

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_base.c | 4 +--
fs/richacl_inode.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 5 +++-
include/linux/richacl.h | 15 ++++++----
6 files changed, 100 insertions(+), 12 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 2a387f4..8462ddb 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)
put_base_acl(inode->i_acl);
+# if defined(CONFIG_FS_POSIX_ACL)
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
put_base_acl(inode->i_default_acl);
+# endif
#endif
this_cpu_dec(nr_inodes);
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index b3b2265..1d766a5 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -38,7 +38,7 @@ struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
struct posix_acl **p = acl_by_type(inode, type);
struct posix_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_base.c b/fs/richacl_base.c
index 4a10174..78e81df 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -33,7 +33,7 @@ richacl_alloc(int count, gfp_t gfp)
struct richacl *acl = kzalloc(size, gfp);

if (acl) {
- atomic_set(&acl->a_refcount, 1);
+ atomic_set(&acl->a_base.ba_refcount, 1);
acl->a_count = count;
}
return acl;
@@ -52,7 +52,7 @@ richacl_clone(const struct richacl *acl, gfp_t gfp)

if (dup) {
memcpy(dup, acl, size);
- atomic_set(&dup->a_refcount, 1);
+ atomic_set(&dup->a_base.ba_refcount, 1);
}
return dup;
}
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 5098717..c0458db 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -20,6 +20,81 @@
#include <linux/slab.h>
#include <linux/richacl.h>

+struct richacl *get_cached_richacl(struct inode *inode)
+{
+ struct richacl *acl;
+
+ acl = (struct richacl *)ACCESS_ONCE(inode->i_acl);
+ if (acl && IS_RICHACL(inode)) {
+ spin_lock(&inode->i_lock);
+ acl = (struct richacl *)inode->i_acl;
+ if (acl != ACL_NOT_CACHED)
+ acl = richacl_get(acl);
+ spin_unlock(&inode->i_lock);
+ }
+ return acl;
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl);
+
+struct richacl *get_cached_richacl_rcu(struct inode *inode)
+{
+ return (struct richacl *)rcu_dereference(inode->i_acl);
+}
+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)
+ put_base_acl(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)
+ put_base_acl(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 08fde42..d91deef 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 a186cb9..3f9dd10 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -33,7 +33,7 @@ struct richace {
};

struct richacl {
- atomic_t a_refcount;
+ struct base_acl a_base;
unsigned int a_owner_mask;
unsigned int a_group_mask;
unsigned int a_other_mask;
@@ -175,8 +175,7 @@ struct richacl {
static inline struct richacl *
richacl_get(struct richacl *acl)
{
- if (acl)
- atomic_inc(&acl->a_base.ba_refcount);
+ get_base_acl(&acl->a_base);
return acl;
}

@@ -186,10 +185,16 @@ richacl_get(struct richacl *acl)
static inline void
richacl_put(struct richacl *acl)
{
- if (acl && atomic_dec_and_test(&acl->a_refcount))
- kfree(acl);
+ BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0);
+ put_base_acl(&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
*/