From 210ad6aedb332e73167ece5af9bd47f0da8c2aca Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 8 Jun 2009 15:22:25 -0400
Subject: ext4: avoid unnecessary spinlock in critical POSIX ACL path

If a filesystem supports POSIX ACL's, the VFS layer expects the filesystem
to do POSIX ACL checks on any files not owned by the caller, and it does
this for every single pathname component that it looks up.

That obviously can be pretty expensive if the filesystem isn't careful
about it, especially with locking. That's doubly sad, since the common
case tends to be that there are no ACL's associated with the files in
question.

ext4 already caches the ACL data so that it doesn't have to look it up
over and over again, but it does so by taking the inode->i_lock spinlock
on every lookup. Which is a noticeable overhead even if it's a private
lock, especially on CPU's where the serialization is expensive (eg Intel
Netburst aka 'P4').

For the special case of not actually having any ACL's, all that locking is
unnecessary. Even if somebody else were to be changing the ACL's on
another CPU, we simply don't care - if we've seen a NULL ACL, we might as
well use it.

So just load the ACL speculatively without any locking, and if it was
NULL, just use it. If it's non-NULL (either because we had a cached
entry, or because the cache hasn't been filled in at all), it means that
we'll need to get the lock and re-load it properly.

(This commit was ported from a patch originally authored by Linus for
ext3.)

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ext4/acl.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

(limited to 'fs/ext4/acl.c')

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 647e0d65a284..605aeed96d68 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -129,12 +129,15 @@ fail:
 static inline struct posix_acl *
 ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
 {
-	struct posix_acl *acl = EXT4_ACL_NOT_CACHED;
+	struct posix_acl *acl = ACCESS_ONCE(*i_acl);
 
-	spin_lock(&inode->i_lock);
-	if (*i_acl != EXT4_ACL_NOT_CACHED)
-		acl = posix_acl_dup(*i_acl);
-	spin_unlock(&inode->i_lock);
+	if (acl) {
+		spin_lock(&inode->i_lock);
+		acl = *i_acl;
+		if (acl != EXT4_ACL_NOT_CACHED)
+			acl = posix_acl_dup(acl);
+		spin_unlock(&inode->i_lock);
+	}
 
 	return acl;
 }
-- 
cgit v1.2.3


From d4bfe2f76d785cc77611a4bda8cedaff358d8c7d Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 8 Jun 2009 19:54:26 -0400
Subject: switch ext4 to inode->i_acl

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ext4/acl.c   | 22 ++++++++++------------
 fs/ext4/acl.h   |  4 ----
 fs/ext4/ext4.h  |  4 ----
 fs/ext4/inode.c |  4 ----
 fs/ext4/super.c | 16 ----------------
 5 files changed, 10 insertions(+), 40 deletions(-)

(limited to 'fs/ext4/acl.c')

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 605aeed96d68..0084e3a19d86 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -134,7 +134,7 @@ ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
 	if (acl) {
 		spin_lock(&inode->i_lock);
 		acl = *i_acl;
-		if (acl != EXT4_ACL_NOT_CACHED)
+		if (acl != ACL_NOT_CACHED)
 			acl = posix_acl_dup(acl);
 		spin_unlock(&inode->i_lock);
 	}
@@ -147,7 +147,7 @@ ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
 		struct posix_acl *acl)
 {
 	spin_lock(&inode->i_lock);
-	if (*i_acl != EXT4_ACL_NOT_CACHED)
+	if (*i_acl != ACL_NOT_CACHED)
 		posix_acl_release(*i_acl);
 	*i_acl = posix_acl_dup(acl);
 	spin_unlock(&inode->i_lock);
@@ -161,7 +161,6 @@ ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
 static struct posix_acl *
 ext4_get_acl(struct inode *inode, int type)
 {
-	struct ext4_inode_info *ei = EXT4_I(inode);
 	int name_index;
 	char *value = NULL;
 	struct posix_acl *acl;
@@ -172,15 +171,15 @@ ext4_get_acl(struct inode *inode, int type)
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		acl = ext4_iget_acl(inode, &ei->i_acl);
-		if (acl != EXT4_ACL_NOT_CACHED)
+		acl = ext4_iget_acl(inode, &inode->i_acl);
+		if (acl != ACL_NOT_CACHED)
 			return acl;
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
 		break;
 
 	case ACL_TYPE_DEFAULT:
-		acl = ext4_iget_acl(inode, &ei->i_default_acl);
-		if (acl != EXT4_ACL_NOT_CACHED)
+		acl = ext4_iget_acl(inode, &inode->i_default_acl);
+		if (acl != ACL_NOT_CACHED)
 			return acl;
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
 		break;
@@ -206,11 +205,11 @@ ext4_get_acl(struct inode *inode, int type)
 	if (!IS_ERR(acl)) {
 		switch (type) {
 		case ACL_TYPE_ACCESS:
-			ext4_iset_acl(inode, &ei->i_acl, acl);
+			ext4_iset_acl(inode, &inode->i_acl, acl);
 			break;
 
 		case ACL_TYPE_DEFAULT:
-			ext4_iset_acl(inode, &ei->i_default_acl, acl);
+			ext4_iset_acl(inode, &inode->i_default_acl, acl);
 			break;
 		}
 	}
@@ -226,7 +225,6 @@ static int
 ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	     struct posix_acl *acl)
 {
-	struct ext4_inode_info *ei = EXT4_I(inode);
 	int name_index;
 	void *value = NULL;
 	size_t size = 0;
@@ -274,11 +272,11 @@ ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	if (!error) {
 		switch (type) {
 		case ACL_TYPE_ACCESS:
-			ext4_iset_acl(inode, &ei->i_acl, acl);
+			ext4_iset_acl(inode, &inode->i_acl, acl);
 			break;
 
 		case ACL_TYPE_DEFAULT:
-			ext4_iset_acl(inode, &ei->i_default_acl, acl);
+			ext4_iset_acl(inode, &inode->i_default_acl, acl);
 			break;
 		}
 	}
diff --git a/fs/ext4/acl.h b/fs/ext4/acl.h
index cb45257a246e..949789d2bba6 100644
--- a/fs/ext4/acl.h
+++ b/fs/ext4/acl.h
@@ -53,10 +53,6 @@ static inline int ext4_acl_count(size_t size)
 
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 
-/* Value for inode->u.ext4_i.i_acl and inode->u.ext4_i.i_default_acl
-   if the ACL has not been cached */
-#define EXT4_ACL_NOT_CACHED ((void *)-1)
-
 /* acl.c */
 extern int ext4_permission(struct inode *, int);
 extern int ext4_acl_chmod(struct inode *);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 17b9998680e3..0ddf7e55abe1 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -595,10 +595,6 @@ struct ext4_inode_info {
 	 */
 	struct rw_semaphore xattr_sem;
 #endif
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	struct posix_acl	*i_acl;
-	struct posix_acl	*i_default_acl;
-#endif
 
 	struct list_head i_orphan;	/* unlinked but open inodes */
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7c17ae275af4..60a26f3a6f8b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4453,10 +4453,6 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 		return inode;
 
 	ei = EXT4_I(inode);
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	ei->i_acl = EXT4_ACL_NOT_CACHED;
-	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
-#endif
 
 	ret = __ext4_get_inode_loc(inode, &iloc, 0);
 	if (ret < 0)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8bb9e2d3e4b8..8f4f079e6b9a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -666,10 +666,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 	if (!ei)
 		return NULL;
 
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	ei->i_acl = EXT4_ACL_NOT_CACHED;
-	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
-#endif
 	ei->vfs_inode.i_version = 1;
 	ei->vfs_inode.i_data.writeback_index = 0;
 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
@@ -735,18 +731,6 @@ static void destroy_inodecache(void)
 
 static void ext4_clear_inode(struct inode *inode)
 {
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	if (EXT4_I(inode)->i_acl &&
-			EXT4_I(inode)->i_acl != EXT4_ACL_NOT_CACHED) {
-		posix_acl_release(EXT4_I(inode)->i_acl);
-		EXT4_I(inode)->i_acl = EXT4_ACL_NOT_CACHED;
-	}
-	if (EXT4_I(inode)->i_default_acl &&
-			EXT4_I(inode)->i_default_acl != EXT4_ACL_NOT_CACHED) {
-		posix_acl_release(EXT4_I(inode)->i_default_acl);
-		EXT4_I(inode)->i_default_acl = EXT4_ACL_NOT_CACHED;
-	}
-#endif
 	ext4_discard_preallocations(inode);
 	if (EXT4_JOURNAL(inode))
 		jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
-- 
cgit v1.2.3


From 073aaa1b142461d91f83da66db1184d7c1b1edea Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 9 Jun 2009 12:11:54 -0400
Subject: helpers for acl caching + switch to those

helpers: get_cached_acl(inode, type), set_cached_acl(inode, type, acl),
forget_cached_acl(inode, type).

ubifs/xattr.c needed includes reordered, the rest is a plain switchover.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/btrfs/acl.c            | 44 +++++--------------------
 fs/ext2/acl.c             | 79 ++++++++++----------------------------------
 fs/ext3/acl.c             | 83 +++++++++++------------------------------------
 fs/ext4/acl.c             | 65 +++++--------------------------------
 fs/jffs2/acl.c            | 60 +++++++---------------------------
 fs/jfs/acl.c              | 32 ++++++++----------
 fs/jfs/xattr.c            | 10 ++----
 fs/reiserfs/xattr_acl.c   | 49 ++++++----------------------
 fs/ubifs/xattr.c          |  2 +-
 include/linux/posix_acl.h | 64 ++++++++++++++++++++++++++++++++++++
 10 files changed, 155 insertions(+), 333 deletions(-)

(limited to 'fs/ext4/acl.c')

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 6db8a42a3e5e..f128427b995b 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -29,51 +29,28 @@
 
 #ifdef CONFIG_FS_POSIX_ACL
 
-static void btrfs_update_cached_acl(struct inode *inode,
-				    struct posix_acl **p_acl,
-				    struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*p_acl && *p_acl != ACL_NOT_CACHED)
-		posix_acl_release(*p_acl);
-	*p_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 {
 	int size;
 	const char *name;
 	char *value = NULL;
-	struct posix_acl *acl = NULL, **p_acl;
+	struct posix_acl *acl;
+
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = POSIX_ACL_XATTR_ACCESS;
-		p_acl = &inode->i_acl;
 		break;
 	case ACL_TYPE_DEFAULT:
 		name = POSIX_ACL_XATTR_DEFAULT;
-		p_acl = &inode->i_default_acl;
 		break;
 	default:
-		return ERR_PTR(-EINVAL);
+		BUG();
 	}
 
-	/* Handle the cached NULL acl case without locking */
-	acl = ACCESS_ONCE(*p_acl);
-	if (!acl)
-		return acl;
-
-	spin_lock(&inode->i_lock);
-	acl = *p_acl;
-	if (acl != ACL_NOT_CACHED)
-		acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-
-	if (acl != ACL_NOT_CACHED)
-		return acl;
-
 	size = __btrfs_getxattr(inode, name, "", 0);
 	if (size > 0) {
 		value = kzalloc(size, GFP_NOFS);
@@ -82,13 +59,13 @@ static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 		size = __btrfs_getxattr(inode, name, value, size);
 		if (size > 0) {
 			acl = posix_acl_from_xattr(value, size);
-			btrfs_update_cached_acl(inode, p_acl, acl);
+			set_cached_acl(inode, type, acl);
 		}
 		kfree(value);
 	} 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);
+		set_cached_acl(inode, type, acl);
 	} else {
 		acl = ERR_PTR(-EIO);
 	}
@@ -121,7 +98,6 @@ static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	int ret, size = 0;
 	const char *name;
-	struct posix_acl **p_acl;
 	char *value = NULL;
 	mode_t mode;
 
@@ -141,13 +117,11 @@ static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 		ret = 0;
 		inode->i_mode = mode;
 		name = POSIX_ACL_XATTR_ACCESS;
-		p_acl = &inode->i_acl;
 		break;
 	case ACL_TYPE_DEFAULT:
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EINVAL : 0;
 		name = POSIX_ACL_XATTR_DEFAULT;
-		p_acl = &inode->i_default_acl;
 		break;
 	default:
 		return -EINVAL;
@@ -172,7 +146,7 @@ out:
 	kfree(value);
 
 	if (!ret)
-		btrfs_update_cached_acl(inode, p_acl, acl);
+		set_cached_acl(inode, type, acl);
 
 	return ret;
 }
diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
index d2ffddc12117..d636e1297cad 100644
--- a/fs/ext2/acl.c
+++ b/fs/ext2/acl.c
@@ -125,30 +125,6 @@ fail:
 	return ERR_PTR(-EINVAL);
 }
 
-static inline struct posix_acl *
-ext2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
-{
-	struct posix_acl *acl = ACL_NOT_CACHED;
-
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		acl = posix_acl_dup(*i_acl);
-	spin_unlock(&inode->i_lock);
-
-	return acl;
-}
-
-static inline void
-ext2_iset_acl(struct inode *inode, struct posix_acl **i_acl,
-		   struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		posix_acl_release(*i_acl);
-	*i_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
 /*
  * inode->i_mutex: don't care
  */
@@ -163,23 +139,19 @@ ext2_get_acl(struct inode *inode, int type)
 	if (!test_opt(inode->i_sb, POSIX_ACL))
 		return NULL;
 
-	switch(type) {
-		case ACL_TYPE_ACCESS:
-			acl = ext2_iget_acl(inode, &inode->i_acl);
-			if (acl != ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
-			break;
-
-		case ACL_TYPE_DEFAULT:
-			acl = ext2_iget_acl(inode, &inode->i_default_acl);
-			if (acl != ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
-			break;
-
-		default:
-			return ERR_PTR(-EINVAL);
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
 	}
 	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
 	if (retval > 0) {
@@ -196,17 +168,9 @@ ext2_get_acl(struct inode *inode, int type)
 		acl = ERR_PTR(retval);
 	kfree(value);
 
-	if (!IS_ERR(acl)) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext2_iset_acl(inode, &inode->i_acl, acl);
-				break;
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
 
-			case ACL_TYPE_DEFAULT:
-				ext2_iset_acl(inode, &inode->i_default_acl, acl);
-				break;
-		}
-	}
 	return acl;
 }
 
@@ -261,17 +225,8 @@ ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
 
 	kfree(value);
-	if (!error) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext2_iset_acl(inode, &inode->i_acl, acl);
-				break;
-
-			case ACL_TYPE_DEFAULT:
-				ext2_iset_acl(inode, &inode->i_default_acl, acl);
-				break;
-		}
-	}
+	if (!error)
+		set_cached_acl(inode, type, acl);
 	return error;
 }
 
diff --git a/fs/ext3/acl.c b/fs/ext3/acl.c
index a9707689d9e1..e167bae37ef0 100644
--- a/fs/ext3/acl.c
+++ b/fs/ext3/acl.c
@@ -126,33 +126,6 @@ fail:
 	return ERR_PTR(-EINVAL);
 }
 
-static inline struct posix_acl *
-ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl)
-{
-	struct posix_acl *acl = ACCESS_ONCE(*i_acl);
-
-	if (acl) {
-		spin_lock(&inode->i_lock);
-		acl = *i_acl;
-		if (acl != ACL_NOT_CACHED)
-			acl = posix_acl_dup(acl);
-		spin_unlock(&inode->i_lock);
-	}
-
-	return acl;
-}
-
-static inline void
-ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
-                  struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		posix_acl_release(*i_acl);
-	*i_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
 /*
  * Inode operation get_posix_acl().
  *
@@ -169,24 +142,21 @@ ext3_get_acl(struct inode *inode, int type)
 	if (!test_opt(inode->i_sb, POSIX_ACL))
 		return NULL;
 
-	switch(type) {
-		case ACL_TYPE_ACCESS:
-			acl = ext3_iget_acl(inode, &inode->i_acl);
-			if (acl != ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
-			break;
-
-		case ACL_TYPE_DEFAULT:
-			acl = ext3_iget_acl(inode, &inode->i_default_acl);
-			if (acl != ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
-			break;
-
-		default:
-			return ERR_PTR(-EINVAL);
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
 	}
+
 	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
 	if (retval > 0) {
 		value = kmalloc(retval, GFP_NOFS);
@@ -202,17 +172,9 @@ ext3_get_acl(struct inode *inode, int type)
 		acl = ERR_PTR(retval);
 	kfree(value);
 
-	if (!IS_ERR(acl)) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext3_iset_acl(inode, &inode->i_acl, acl);
-				break;
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
 
-			case ACL_TYPE_DEFAULT:
-				ext3_iset_acl(inode, &inode->i_default_acl, acl);
-				break;
-		}
-	}
 	return acl;
 }
 
@@ -269,17 +231,10 @@ ext3_set_acl(handle_t *handle, struct inode *inode, int type,
 				      value, size, 0);
 
 	kfree(value);
-	if (!error) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext3_iset_acl(inode, &inode->i_acl, acl);
-				break;
 
-			case ACL_TYPE_DEFAULT:
-				ext3_iset_acl(inode, &inode->i_default_acl, acl);
-				break;
-		}
-	}
+	if (!error)
+		set_cached_acl(inode, type, acl);
+
 	return error;
 }
 
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 0084e3a19d86..f6d8967149ca 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -126,33 +126,6 @@ fail:
 	return ERR_PTR(-EINVAL);
 }
 
-static inline struct posix_acl *
-ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
-{
-	struct posix_acl *acl = ACCESS_ONCE(*i_acl);
-
-	if (acl) {
-		spin_lock(&inode->i_lock);
-		acl = *i_acl;
-		if (acl != ACL_NOT_CACHED)
-			acl = posix_acl_dup(acl);
-		spin_unlock(&inode->i_lock);
-	}
-
-	return acl;
-}
-
-static inline void
-ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
-		struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		posix_acl_release(*i_acl);
-	*i_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
 /*
  * Inode operation get_posix_acl().
  *
@@ -169,23 +142,19 @@ ext4_get_acl(struct inode *inode, int type)
 	if (!test_opt(inode->i_sb, POSIX_ACL))
 		return NULL;
 
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		acl = ext4_iget_acl(inode, &inode->i_acl);
-		if (acl != ACL_NOT_CACHED)
-			return acl;
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
 		break;
-
 	case ACL_TYPE_DEFAULT:
-		acl = ext4_iget_acl(inode, &inode->i_default_acl);
-		if (acl != ACL_NOT_CACHED)
-			return acl;
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
 		break;
-
 	default:
-		return ERR_PTR(-EINVAL);
+		BUG();
 	}
 	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
 	if (retval > 0) {
@@ -202,17 +171,9 @@ ext4_get_acl(struct inode *inode, int type)
 		acl = ERR_PTR(retval);
 	kfree(value);
 
-	if (!IS_ERR(acl)) {
-		switch (type) {
-		case ACL_TYPE_ACCESS:
-			ext4_iset_acl(inode, &inode->i_acl, acl);
-			break;
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
 
-		case ACL_TYPE_DEFAULT:
-			ext4_iset_acl(inode, &inode->i_default_acl, acl);
-			break;
-		}
-	}
 	return acl;
 }
 
@@ -269,17 +230,9 @@ ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 				      value, size, 0);
 
 	kfree(value);
-	if (!error) {
-		switch (type) {
-		case ACL_TYPE_ACCESS:
-			ext4_iset_acl(inode, &inode->i_acl, acl);
-			break;
+	if (!error)
+		set_cached_acl(inode, type, acl);
 
-		case ACL_TYPE_DEFAULT:
-			ext4_iset_acl(inode, &inode->i_default_acl, acl);
-			break;
-		}
-	}
 	return error;
 }
 
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
index ac16589ebbd1..edd2ad6416d8 100644
--- a/fs/jffs2/acl.c
+++ b/fs/jffs2/acl.c
@@ -156,47 +156,25 @@ static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
 	return ERR_PTR(-EINVAL);
 }
 
-static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
-{
-	struct posix_acl *acl = ACL_NOT_CACHED;
-
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		acl = posix_acl_dup(*i_acl);
-	spin_unlock(&inode->i_lock);
-	return acl;
-}
-
-static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		posix_acl_release(*i_acl);
-	*i_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
 static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
 {
 	struct posix_acl *acl;
 	char *value = NULL;
 	int rc, xprefix;
 
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		acl = jffs2_iget_acl(inode, &inode->i_acl);
-		if (acl != ACL_NOT_CACHED)
-			return acl;
 		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 		break;
 	case ACL_TYPE_DEFAULT:
-		acl = jffs2_iget_acl(inode, &inode->i_default_acl);
-		if (acl != ACL_NOT_CACHED)
-			return acl;
 		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 		break;
 	default:
-		return ERR_PTR(-EINVAL);
+		BUG();
 	}
 	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
 	if (rc > 0) {
@@ -214,16 +192,8 @@ static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
 	}
 	if (value)
 		kfree(value);
-	if (!IS_ERR(acl)) {
-		switch (type) {
-		case ACL_TYPE_ACCESS:
-			jffs2_iset_acl(inode, &inode->i_acl, acl);
-			break;
-		case ACL_TYPE_DEFAULT:
-			jffs2_iset_acl(inode, &inode->i_default_acl, acl);
-			break;
-		}
-	}
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
 	return acl;
 }
 
@@ -283,16 +253,8 @@ static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 		return -EINVAL;
 	}
 	rc = __jffs2_set_acl(inode, xprefix, acl);
-	if (!rc) {
-		switch(type) {
-		case ACL_TYPE_ACCESS:
-			jffs2_iset_acl(inode, &inode->i_acl, acl);
-			break;
-		case ACL_TYPE_DEFAULT:
-			jffs2_iset_acl(inode, &inode->i_default_acl, acl);
-			break;
-		}
-	}
+	if (!rc)
+		set_cached_acl(inode, type, acl);
 	return rc;
 }
 
@@ -336,7 +298,7 @@ int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
 		*i_mode &= ~current_umask();
 	} else {
 		if (S_ISDIR(*i_mode))
-			jffs2_iset_acl(inode, &inode->i_default_acl, acl);
+			set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
 
 		clone = posix_acl_clone(acl, GFP_KERNEL);
 		if (!clone)
@@ -347,7 +309,7 @@ int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
 			return rc;
 		}
 		if (rc > 0)
-			jffs2_iset_acl(inode, &inode->i_acl, clone);
+			set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
 
 		posix_acl_release(clone);
 	}
diff --git a/fs/jfs/acl.c b/fs/jfs/acl.c
index 5fcfc9857c11..f272bf032e1e 100644
--- a/fs/jfs/acl.c
+++ b/fs/jfs/acl.c
@@ -31,26 +31,24 @@ static struct posix_acl *jfs_get_acl(struct inode *inode, int type)
 {
 	struct posix_acl *acl;
 	char *ea_name;
-	struct posix_acl **p_acl;
 	int size;
 	char *value = NULL;
 
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
 	switch(type) {
 		case ACL_TYPE_ACCESS:
 			ea_name = POSIX_ACL_XATTR_ACCESS;
-			p_acl = &inode->i_acl;
 			break;
 		case ACL_TYPE_DEFAULT:
 			ea_name = POSIX_ACL_XATTR_DEFAULT;
-			p_acl = &inode->i_default_acl;
 			break;
 		default:
 			return ERR_PTR(-EINVAL);
 	}
 
-	if (*p_acl != ACL_NOT_CACHED)
-		return posix_acl_dup(*p_acl);
-
 	size = __jfs_getxattr(inode, ea_name, NULL, 0);
 
 	if (size > 0) {
@@ -61,17 +59,18 @@ static struct posix_acl *jfs_get_acl(struct inode *inode, int type)
 	}
 
 	if (size < 0) {
-		if (size == -ENODATA) {
-			*p_acl = NULL;
+		if (size == -ENODATA)
 			acl = NULL;
-		} else
+		else
 			acl = ERR_PTR(size);
 	} else {
 		acl = posix_acl_from_xattr(value, size);
-		if (!IS_ERR(acl))
-			*p_acl = posix_acl_dup(acl);
 	}
 	kfree(value);
+	if (!IS_ERR(acl)) {
+		set_cached_acl(inode, type, acl);
+		posix_acl_release(acl);
+	}
 	return acl;
 }
 
@@ -79,7 +78,6 @@ static int jfs_set_acl(tid_t tid, struct inode *inode, int type,
 		       struct posix_acl *acl)
 {
 	char *ea_name;
-	struct posix_acl **p_acl;
 	int rc;
 	int size = 0;
 	char *value = NULL;
@@ -90,11 +88,9 @@ static int jfs_set_acl(tid_t tid, struct inode *inode, int type,
 	switch(type) {
 		case ACL_TYPE_ACCESS:
 			ea_name = POSIX_ACL_XATTR_ACCESS;
-			p_acl = &inode->i_acl;
 			break;
 		case ACL_TYPE_DEFAULT:
 			ea_name = POSIX_ACL_XATTR_DEFAULT;
-			p_acl = &inode->i_default_acl;
 			if (!S_ISDIR(inode->i_mode))
 				return acl ? -EACCES : 0;
 			break;
@@ -114,11 +110,9 @@ static int jfs_set_acl(tid_t tid, struct inode *inode, int type,
 out:
 	kfree(value);
 
-	if (!rc) {
-		if (*p_acl && (*p_acl != ACL_NOT_CACHED))
-			posix_acl_release(*p_acl);
-		*p_acl = posix_acl_dup(acl);
-	}
+	if (!rc)
+		set_cached_acl(inode, type, acl);
+
 	return rc;
 }
 
diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index f6e90e343593..fad364548bc9 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -727,10 +727,7 @@ static int can_set_system_xattr(struct inode *inode, const char *name,
 		/*
 		 * We're changing the ACL.  Get rid of the cached one
 		 */
-		acl =inode->i_acl;
-		if (acl != ACL_NOT_CACHED)
-			posix_acl_release(acl);
-		inode->i_acl = ACL_NOT_CACHED;
+		forget_cached_acl(inode, ACL_TYPE_ACCESS);
 
 		return 0;
 	} else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
@@ -746,10 +743,7 @@ static int can_set_system_xattr(struct inode *inode, const char *name,
 		/*
 		 * We're changing the default ACL.  Get rid of the cached one
 		 */
-		acl = inode->i_default_acl;
-		if (acl && (acl != ACL_NOT_CACHED))
-			posix_acl_release(acl);
-		inode->i_default_acl = ACL_NOT_CACHED;
+		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
 
 		return 0;
 	}
diff --git a/fs/reiserfs/xattr_acl.c b/fs/reiserfs/xattr_acl.c
index b6e473faa8b8..35d6e672a279 100644
--- a/fs/reiserfs/xattr_acl.c
+++ b/fs/reiserfs/xattr_acl.c
@@ -188,29 +188,6 @@ static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 	return ERR_PTR(-EINVAL);
 }
 
-static inline void iset_acl(struct inode *inode, struct posix_acl **i_acl,
-			    struct posix_acl *acl)
-{
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		posix_acl_release(*i_acl);
-	*i_acl = posix_acl_dup(acl);
-	spin_unlock(&inode->i_lock);
-}
-
-static inline struct posix_acl *iget_acl(struct inode *inode,
-					 struct posix_acl **i_acl)
-{
-	struct posix_acl *acl = ACL_NOT_CACHED;
-
-	spin_lock(&inode->i_lock);
-	if (*i_acl != ACL_NOT_CACHED)
-		acl = posix_acl_dup(*i_acl);
-	spin_unlock(&inode->i_lock);
-
-	return acl;
-}
-
 /*
  * Inode operation get_posix_acl().
  *
@@ -220,31 +197,29 @@ static inline struct posix_acl *iget_acl(struct inode *inode,
 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 {
 	char *name, *value;
-	struct posix_acl *acl, **p_acl;
+	struct posix_acl *acl;
 	int size;
 	int retval;
 
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = POSIX_ACL_XATTR_ACCESS;
-		p_acl = &inode->i_acl;
 		break;
 	case ACL_TYPE_DEFAULT:
 		name = POSIX_ACL_XATTR_DEFAULT;
-		p_acl = &inode->i_default_acl;
 		break;
 	default:
-		return ERR_PTR(-EINVAL);
+		BUG();
 	}
 
-	acl = iget_acl(inode, p_acl);
-	if (acl != ACL_NOT_CACHED)
-		return acl;
-
 	size = reiserfs_xattr_get(inode, name, NULL, 0);
 	if (size < 0) {
 		if (size == -ENODATA || size == -ENOSYS) {
-			*p_acl = NULL;
+			set_cached_acl(inode, type, NULL);
 			return NULL;
 		}
 		return ERR_PTR(size);
@@ -259,14 +234,13 @@ struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 		/* This shouldn't actually happen as it should have
 		   been caught above.. but just in case */
 		acl = NULL;
-		*p_acl = acl;
 	} else if (retval < 0) {
 		acl = ERR_PTR(retval);
 	} else {
 		acl = posix_acl_from_disk(value, retval);
-		if (!IS_ERR(acl))
-			iset_acl(inode, p_acl, acl);
 	}
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
 
 	kfree(value);
 	return acl;
@@ -284,7 +258,6 @@ reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 {
 	char *name;
 	void *value = NULL;
-	struct posix_acl **p_acl;
 	size_t size = 0;
 	int error;
 
@@ -294,7 +267,6 @@ reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = POSIX_ACL_XATTR_ACCESS;
-		p_acl = &inode->i_acl;
 		if (acl) {
 			mode_t mode = inode->i_mode;
 			error = posix_acl_equiv_mode(acl, &mode);
@@ -309,7 +281,6 @@ reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 		break;
 	case ACL_TYPE_DEFAULT:
 		name = POSIX_ACL_XATTR_DEFAULT;
-		p_acl = &inode->i_default_acl;
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EACCES : 0;
 		break;
@@ -342,7 +313,7 @@ reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 	kfree(value);
 
 	if (!error)
-		iset_acl(inode, p_acl, acl);
+		set_cached_acl(inode, type, acl);
 
 	return error;
 }
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index cfd31e229c89..adafcf556531 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -55,9 +55,9 @@
  * ACL support is not implemented.
  */
 
+#include "ubifs.h"
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>
-#include "ubifs.h"
 
 /*
  * Limit the number of extended attributes per inode so that the total size
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 4bc241290c24..0cdba01b7756 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -83,4 +83,68 @@ extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
 extern struct posix_acl *get_posix_acl(struct inode *, int);
 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
 
+static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl **p, *acl;
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		p = &inode->i_acl;
+		break;
+	case ACL_TYPE_DEFAULT:
+		p = &inode->i_default_acl;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+	acl = ACCESS_ONCE(*p);
+	if (acl) {
+		spin_lock(&inode->i_lock);
+		acl = *p;
+		if (acl != ACL_NOT_CACHED)
+			acl = posix_acl_dup(acl);
+		spin_unlock(&inode->i_lock);
+	}
+	return acl;
+}
+
+static inline void set_cached_acl(struct inode *inode,
+				  int type,
+				  struct posix_acl *acl)
+{
+	struct posix_acl *old = NULL;
+	spin_lock(&inode->i_lock);
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		old = inode->i_acl;
+		inode->i_acl = posix_acl_dup(acl);
+		break;
+	case ACL_TYPE_DEFAULT:
+		old = inode->i_default_acl;
+		inode->i_default_acl = posix_acl_dup(acl);
+		break;
+	}
+	spin_unlock(&inode->i_lock);
+	if (old != ACL_NOT_CACHED)
+		posix_acl_release(old);
+}
+
+static inline void forget_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl *old = NULL;
+	spin_lock(&inode->i_lock);
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		old = inode->i_acl;
+		inode->i_acl = ACL_NOT_CACHED;
+		break;
+	case ACL_TYPE_DEFAULT:
+		old = inode->i_default_acl;
+		inode->i_default_acl = ACL_NOT_CACHED;
+		break;
+	}
+	spin_unlock(&inode->i_lock);
+	if (old != ACL_NOT_CACHED)
+		posix_acl_release(old);
+}
+
 #endif  /* __LINUX_POSIX_ACL_H */
-- 
cgit v1.2.3