[RFC v7 11/41] vfs: Cache base_acl objects in inodes

From: Andreas Gruenbacher
Date: Sat Sep 05 2015 - 06:30:19 EST

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POSIX ACLs and richacls are both objects allocated by kmalloc() with a
reference count which are freed by kfree_rcu(). An inode can either
cache an access and a default POSIX ACL, or a richacl (richacls do not
have default acls). To allow an inode to cache either of the two kinds
of acls, introduce a new base_acl type and convert i_acl and
i_default_acl to that type. In most cases, the vfs then doesn't have to
care which kind of acl an inode caches (if any).

Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +-
fs/f2fs/acl.c | 4 ++--
fs/inode.c | 4 ++--
fs/jffs2/acl.c | 6 ++++--
fs/posix_acl.c | 18 +++++++++---------
include/linux/fs.h | 25 ++++++++++++++++++++++---
include/linux/posix_acl.h | 12 ++++--------
include/linux/richacl.h | 2 +-
8 files changed, 45 insertions(+), 28 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index 2513988..e198f63 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -1130,7 +1130,7 @@ void ll_clear_inode(struct inode *inode)
}
#ifdef CONFIG_FS_POSIX_ACL
else if (lli->lli_posix_acl) {
- LASSERT(atomic_read(&lli->lli_posix_acl->a_refcount) == 1);
+ LASSERT(atomic_read(&lli->lli_posix_acl->a_base.ba_refcount) == 1);
LASSERT(lli->lli_remote_perms == NULL);
posix_acl_release(lli->lli_posix_acl);
lli->lli_posix_acl = NULL;
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index c8f25f7..a4207de 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -270,7 +270,7 @@ static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
- atomic_set(&clone->a_refcount, 1);
+ atomic_set(&clone->a_base.ba_refcount, 1);
}
return clone;
}
@@ -282,7 +282,7 @@ static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
umode_t mode = *mode_p;
int not_equiv = 0;

- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(atomic_read(acl->a_base.ba_refcount) == 1); */

FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
diff --git a/fs/inode.c b/fs/inode.c
index d30640f..00b442d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -235,9 +235,9 @@ void __destroy_inode(struct inode *inode)

#ifdef CONFIG_FS_POSIX_ACL
if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
- posix_acl_release(inode->i_acl);
+ put_base_acl(inode->i_acl);
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
- posix_acl_release(inode->i_default_acl);
+ put_base_acl(inode->i_default_acl);
#endif
this_cpu_dec(nr_inodes);
}
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
index 2f7a3c0..04a5836 100644
--- a/fs/jffs2/acl.c
+++ b/fs/jffs2/acl.c
@@ -294,13 +294,15 @@ int jffs2_init_acl_post(struct inode *inode)
int rc;

if (inode->i_default_acl) {
- rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
+ rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT,
+ *acl_by_type(inode, ACL_TYPE_DEFAULT));
if (rc)
return rc;
}

if (inode->i_acl) {
- rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
+ rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS,
+ *acl_by_type(inode, ACL_TYPE_ACCESS));
if (rc)
return rc;
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 4fb17de..b3b2265 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -25,9 +25,9 @@ struct posix_acl **acl_by_type(struct inode *inode, int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
- return &inode->i_acl;
+ return (struct posix_acl **)&inode->i_acl;
case ACL_TYPE_DEFAULT:
- return &inode->i_default_acl;
+ return (struct posix_acl **)&inode->i_default_acl;
default:
BUG();
}
@@ -83,16 +83,16 @@ EXPORT_SYMBOL(forget_cached_acl);

void forget_all_cached_acls(struct inode *inode)
{
- struct posix_acl *old_access, *old_default;
+ struct base_acl *old_access, *old_default;
spin_lock(&inode->i_lock);
old_access = inode->i_acl;
old_default = inode->i_default_acl;
inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
spin_unlock(&inode->i_lock);
if (old_access != ACL_NOT_CACHED)
- posix_acl_release(old_access);
+ put_base_acl(old_access);
if (old_default != ACL_NOT_CACHED)
- posix_acl_release(old_default);
+ put_base_acl(old_default);
}
EXPORT_SYMBOL(forget_all_cached_acls);

@@ -129,7 +129,7 @@ EXPORT_SYMBOL(get_acl);
void
posix_acl_init(struct posix_acl *acl, int count)
{
- atomic_set(&acl->a_refcount, 1);
+ atomic_set(&acl->a_base.ba_refcount, 1);
acl->a_count = count;
}
EXPORT_SYMBOL(posix_acl_init);
@@ -162,7 +162,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
- atomic_set(&clone->a_refcount, 1);
+ atomic_set(&clone->a_base.ba_refcount, 1);
}
return clone;
}
@@ -384,7 +384,7 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
umode_t mode = *mode_p;
int not_equiv = 0;

- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(atomic_read(acl->a_base.ba_refcount) == 1); */

FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
@@ -439,7 +439,7 @@ static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
struct posix_acl_entry *pa, *pe;

- /* assert(atomic_read(acl->a_refcount) == 1); */
+ /* assert(atomic_read(acl->a_base.ba_refcount) == 1); */

FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index add0a02..04dddfa 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -576,6 +576,12 @@ static inline void mapping_allow_writable(struct address_space *mapping)
#define i_size_ordered_init(inode) do { } while (0)
#endif

+struct base_acl {
+ union {
+ atomic_t ba_refcount;
+ struct rcu_head ba_rcu;
+ };
+};
struct posix_acl;
#define ACL_NOT_CACHED ((void *)(-1))

@@ -595,9 +601,9 @@ struct inode {
kgid_t i_gid;
unsigned int i_flags;

-#ifdef CONFIG_FS_POSIX_ACL
- struct posix_acl *i_acl;
- struct posix_acl *i_default_acl;
+#if defined(CONFIG_FS_POSIX_ACL)
+ struct base_acl *i_acl;
+ struct base_acl *i_default_acl;
#endif

const struct inode_operations *i_op;
@@ -3060,4 +3066,17 @@ static inline bool dir_relax(struct inode *inode)
return !IS_DEADDIR(inode);
}

+static inline struct base_acl *get_base_acl(struct base_acl *acl)
+{
+ if (acl)
+ atomic_inc(&acl->ba_refcount);
+ return acl;
+}
+
+static inline void put_base_acl(struct base_acl *acl)
+{
+ if (acl && atomic_dec_and_test(&acl->ba_refcount))
+ kfree_rcu(acl, ba_rcu);
+}
+
#endif /* _LINUX_FS_H */
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 3e96a6a..2c46441 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -43,10 +43,7 @@ struct posix_acl_entry {
};

struct posix_acl {
- union {
- atomic_t a_refcount;
- struct rcu_head a_rcu;
- };
+ struct base_acl a_base;
unsigned int a_count;
struct posix_acl_entry a_entries[0];
};
@@ -61,8 +58,7 @@ struct posix_acl {
static inline struct posix_acl *
posix_acl_dup(struct posix_acl *acl)
{
- if (acl)
- atomic_inc(&acl->a_refcount);
+ get_base_acl(&acl->a_base);
return acl;
}

@@ -72,8 +68,8 @@ posix_acl_dup(struct posix_acl *acl)
static inline void
posix_acl_release(struct posix_acl *acl)
{
- if (acl && atomic_dec_and_test(&acl->a_refcount))
- kfree_rcu(acl, a_rcu);
+ BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0);
+ put_base_acl(&acl->a_base);
}

diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 9768eeb..61836f1 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -176,7 +176,7 @@ static inline struct richacl *
richacl_get(struct richacl *acl)
{
if (acl)
- atomic_inc(&acl->a_refcount);
+ atomic_inc(&acl->a_base.ba_refcount);
return acl;
}

--
2.4.3

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Next message: Andreas Gruenbacher: "[RFC v7 16/41] richacl: xattr mapping functions"
Previous message: Andreas Gruenbacher: "[RFC v7 06/41] richacl: In-memory representation and helper functions"
In reply to: Andreas Gruenbacher: "[RFC v7 06/41] richacl: In-memory representation and helper functions"
Next in thread: Andreas Gruenbacher: "[RFC v7 16/41] richacl: xattr mapping functions"
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