[PATCH 0/2] allow overlayfs to do RCU lookups

[PATCH 0/2] allow overlayfs to do RCU lookups

[Miklos Szeredi]

This mini-series enables RCU lookups for overlayfs.

Al, can you take this into your tree, or at least ack the vfs changes so I
can push this to the overlayfs tree?

Thanks,
Miklos

---
Miklos Szeredi (2):
  vfs: add flags argument to ->get_acl() callback
  ovl: enable RCU'd ->get_acl()

 Documentation/filesystems/locking.rst |  2 +-
 Documentation/filesystems/vfs.rst     |  2 +-
 fs/9p/acl.c                           |  5 ++++-
 fs/9p/acl.h                           |  2 +-
 fs/bad_inode.c                        |  2 +-
 fs/btrfs/acl.c                        |  5 ++++-
 fs/btrfs/ctree.h                      |  2 +-
 fs/ceph/acl.c                         |  5 ++++-
 fs/ceph/super.h                       |  2 +-
 fs/erofs/xattr.c                      |  5 ++++-
 fs/erofs/xattr.h                      |  2 +-
 fs/ext2/acl.c                         |  5 ++++-
 fs/ext2/acl.h                         |  2 +-
 fs/ext4/acl.c                         |  5 ++++-
 fs/ext4/acl.h                         |  2 +-
 fs/f2fs/acl.c                         |  5 ++++-
 fs/f2fs/acl.h                         |  2 +-
 fs/fuse/acl.c                         |  5 ++++-
 fs/fuse/fuse_i.h                      |  2 +-
 fs/gfs2/acl.c                         |  5 ++++-
 fs/gfs2/acl.h                         |  2 +-
 fs/jffs2/acl.c                        |  5 ++++-
 fs/jffs2/acl.h                        |  2 +-
 fs/jfs/acl.c                          |  5 ++++-
 fs/jfs/jfs_acl.h                      |  2 +-
 fs/nfs/nfs3_fs.h                      |  2 +-
 fs/nfs/nfs3acl.c                      |  5 ++++-
 fs/ocfs2/acl.c                        |  5 ++++-
 fs/ocfs2/acl.h                        |  2 +-
 fs/orangefs/acl.c                     |  5 ++++-
 fs/orangefs/orangefs-kernel.h         |  2 +-
 fs/overlayfs/inode.c                  |  6 +++++-
 fs/overlayfs/overlayfs.h              |  2 +-
 fs/posix_acl.c                        | 10 ++++++++--
 fs/reiserfs/acl.h                     |  2 +-
 fs/reiserfs/xattr_acl.c               |  5 ++++-
 fs/xfs/xfs_acl.c                      |  5 ++++-
 fs/xfs/xfs_acl.h                      |  4 ++--
 include/linux/fs.h                    |  7 ++++++-
 39 files changed, 104 insertions(+), 41 deletions(-)

-- 
2.31.1

[PATCH 1/2] vfs: add flags argument to ->get_acl() callback

[Miklos Szeredi]

Add a flags argument to the ->get_acl() callback, to allow
get_cached_acl_rcu() to call the ->get_acl() method with LOOKUP_RCU.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 Documentation/filesystems/locking.rst | 2 +-
 Documentation/filesystems/vfs.rst     | 2 +-
 fs/9p/acl.c                           | 5 ++++-
 fs/9p/acl.h                           | 2 +-
 fs/bad_inode.c                        | 2 +-
 fs/btrfs/acl.c                        | 5 ++++-
 fs/btrfs/ctree.h                      | 2 +-
 fs/ceph/acl.c                         | 5 ++++-
 fs/ceph/super.h                       | 2 +-
 fs/erofs/xattr.c                      | 5 ++++-
 fs/erofs/xattr.h                      | 2 +-
 fs/ext2/acl.c                         | 5 ++++-
 fs/ext2/acl.h                         | 2 +-
 fs/ext4/acl.c                         | 5 ++++-
 fs/ext4/acl.h                         | 2 +-
 fs/f2fs/acl.c                         | 5 ++++-
 fs/f2fs/acl.h                         | 2 +-
 fs/fuse/acl.c                         | 5 ++++-
 fs/fuse/fuse_i.h                      | 2 +-
 fs/gfs2/acl.c                         | 5 ++++-
 fs/gfs2/acl.h                         | 2 +-
 fs/jffs2/acl.c                        | 5 ++++-
 fs/jffs2/acl.h                        | 2 +-
 fs/jfs/acl.c                          | 5 ++++-
 fs/jfs/jfs_acl.h                      | 2 +-
 fs/nfs/nfs3_fs.h                      | 2 +-
 fs/nfs/nfs3acl.c                      | 5 ++++-
 fs/ocfs2/acl.c                        | 5 ++++-
 fs/ocfs2/acl.h                        | 2 +-
 fs/orangefs/acl.c                     | 5 ++++-
 fs/orangefs/orangefs-kernel.h         | 2 +-
 fs/overlayfs/inode.c                  | 5 ++++-
 fs/overlayfs/overlayfs.h              | 2 +-
 fs/posix_acl.c                        | 2 +-
 fs/reiserfs/acl.h                     | 2 +-
 fs/reiserfs/xattr_acl.c               | 5 ++++-
 fs/xfs/xfs_acl.c                      | 5 ++++-
 fs/xfs/xfs_acl.h                      | 4 ++--
 include/linux/fs.h                    | 2 +-
 39 files changed, 91 insertions(+), 40 deletions(-)

diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index 2183fd8cc350..a6a8f2b34331 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -70,7 +70,7 @@ prototypes::
 	const char *(*get_link) (struct dentry *, struct inode *, struct delayed_call *);
 	void (*truncate) (struct inode *);
 	int (*permission) (struct inode *, int, unsigned int);
-	int (*get_acl)(struct inode *, int);
+	struct posix_acl * (*get_acl)(struct inode *, int, int);
 	int (*setattr) (struct dentry *, struct iattr *);
 	int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index 14c31eced416..dc9339acb66f 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -432,7 +432,7 @@ As of kernel 2.6.22, the following members are defined:
 		const char *(*get_link) (struct dentry *, struct inode *,
 					 struct delayed_call *);
 		int (*permission) (struct user_namespace *, struct inode *, int);
-		int (*get_acl)(struct inode *, int);
+		struct posix_acl * (*get_acl)(struct inode *, int, int);
 		int (*setattr) (struct user_namespace *, struct dentry *, struct iattr *);
 		int (*getattr) (struct user_namespace *, const struct path *, struct kstat *, u32, unsigned int);
 		ssize_t (*listxattr) (struct dentry *, char *, size_t);
diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index bb1b286c49ae..3ef7db80fe29 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -97,10 +97,13 @@ static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
 	return acl;
 }
 
-struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type)
+struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, int flags)
 {
 	struct v9fs_session_info *v9ses;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	v9ses = v9fs_inode2v9ses(inode);
 	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
 			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
diff --git a/fs/9p/acl.h b/fs/9p/acl.h
index e4f7e882272b..7b31cef9ef5a 100644
--- a/fs/9p/acl.h
+++ b/fs/9p/acl.h
@@ -16,7 +16,7 @@
 
 #ifdef CONFIG_9P_FS_POSIX_ACL
 extern int v9fs_get_acl(struct inode *, struct p9_fid *);
-extern struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type);
+extern struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, int flags);
 extern int v9fs_acl_chmod(struct inode *, struct p9_fid *);
 extern int v9fs_set_create_acl(struct inode *, struct p9_fid *,
 			       struct posix_acl *, struct posix_acl *);
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 48e16144c1f7..dd34decddaa6 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -121,7 +121,7 @@ static const char *bad_inode_get_link(struct dentry *dentry,
 	return ERR_PTR(-EIO);
 }
 
-static struct posix_acl *bad_inode_get_acl(struct inode *inode, int type)
+static struct posix_acl *bad_inode_get_acl(struct inode *inode, int type, int flags)
 {
 	return ERR_PTR(-EIO);
 }
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index d95eb5c8cb37..b53d55186e4a 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -16,13 +16,16 @@
 #include "btrfs_inode.h"
 #include "xattr.h"
 
-struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
+struct posix_acl *btrfs_get_acl(struct inode *inode, int type, int flags)
 {
 	int size;
 	const char *name;
 	char *value = NULL;
 	struct posix_acl *acl;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = XATTR_NAME_POSIX_ACL_ACCESS;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e5e53e592d4f..460a64266066 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3686,7 +3686,7 @@ static inline int __btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag)
 
 /* acl.c */
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
-struct posix_acl *btrfs_get_acl(struct inode *inode, int type);
+struct posix_acl *btrfs_get_acl(struct inode *inode, int type, int flags);
 int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		  struct posix_acl *acl, int type);
 int btrfs_init_acl(struct btrfs_trans_handle *trans,
diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
index 529af59d9fd3..61e4f866d162 100644
--- a/fs/ceph/acl.c
+++ b/fs/ceph/acl.c
@@ -29,7 +29,7 @@ static inline void ceph_set_cached_acl(struct inode *inode,
 	spin_unlock(&ci->i_ceph_lock);
 }
 
-struct posix_acl *ceph_get_acl(struct inode *inode, int type)
+struct posix_acl *ceph_get_acl(struct inode *inode, int type, int flags)
 {
 	int size;
 	unsigned int retry_cnt = 0;
@@ -37,6 +37,9 @@ struct posix_acl *ceph_get_acl(struct inode *inode, int type)
 	char *value = NULL;
 	struct posix_acl *acl;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = XATTR_NAME_POSIX_ACL_ACCESS;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 6b6332a5c113..528975f199eb 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1087,7 +1087,7 @@ void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx);
 /* acl.c */
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 
-struct posix_acl *ceph_get_acl(struct inode *, int);
+struct posix_acl *ceph_get_acl(struct inode *, int, int);
 int ceph_set_acl(struct user_namespace *mnt_userns,
 		 struct inode *inode, struct posix_acl *acl, int type);
 int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 8dd54b420a1d..10c0d639d794 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -673,12 +673,15 @@ ssize_t erofs_listxattr(struct dentry *dentry,
 }
 
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-struct posix_acl *erofs_get_acl(struct inode *inode, int type)
+struct posix_acl *erofs_get_acl(struct inode *inode, int type, int flags)
 {
 	struct posix_acl *acl;
 	int prefix, rc;
 	char *value = NULL;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index 366dcb400525..ac35b5886eff 100644
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -80,7 +80,7 @@ static inline int erofs_getxattr(struct inode *inode, int index,
 #endif	/* !CONFIG_EROFS_FS_XATTR */
 
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-struct posix_acl *erofs_get_acl(struct inode *inode, int type);
+struct posix_acl *erofs_get_acl(struct inode *inode, int type, int flags);
 #else
 #define erofs_get_acl	(NULL)
 #endif
diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
index b9a9db98e94b..e203ebd224c4 100644
--- a/fs/ext2/acl.c
+++ b/fs/ext2/acl.c
@@ -141,13 +141,16 @@ ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
  * inode->i_mutex: don't care
  */
 struct posix_acl *
-ext2_get_acl(struct inode *inode, int type)
+ext2_get_acl(struct inode *inode, int type, int flags)
 {
 	int name_index;
 	char *value = NULL;
 	struct posix_acl *acl;
 	int retval;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
diff --git a/fs/ext2/acl.h b/fs/ext2/acl.h
index 917db5f6630a..0bd53a953831 100644
--- a/fs/ext2/acl.h
+++ b/fs/ext2/acl.h
@@ -55,7 +55,7 @@ static inline int ext2_acl_count(size_t size)
 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 
 /* acl.c */
-extern struct posix_acl *ext2_get_acl(struct inode *inode, int type);
+extern struct posix_acl *ext2_get_acl(struct inode *inode, int type, int flags);
 extern int ext2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 			struct posix_acl *acl, int type);
 extern int ext2_init_acl (struct inode *, struct inode *);
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index c5eaffccecc3..e4e27e34a221 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -142,13 +142,16 @@ ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
  * inode->i_mutex: don't care
  */
 struct posix_acl *
-ext4_get_acl(struct inode *inode, int type)
+ext4_get_acl(struct inode *inode, int type, int flags)
 {
 	int name_index;
 	char *value = NULL;
 	struct posix_acl *acl;
 	int retval;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
diff --git a/fs/ext4/acl.h b/fs/ext4/acl.h
index 84b8942a57f2..b349365c7b33 100644
--- a/fs/ext4/acl.h
+++ b/fs/ext4/acl.h
@@ -55,7 +55,7 @@ static inline int ext4_acl_count(size_t size)
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 
 /* acl.c */
-struct posix_acl *ext4_get_acl(struct inode *inode, int type);
+struct posix_acl *ext4_get_acl(struct inode *inode, int type, int flags);
 int ext4_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		 struct posix_acl *acl, int type);
 extern int ext4_init_acl(handle_t *, struct inode *, struct inode *);
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index 239ad9453b99..4d1b348a0ab7 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -196,8 +196,11 @@ static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
 	return acl;
 }
 
-struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
+struct posix_acl *f2fs_get_acl(struct inode *inode, int type, int flags)
 {
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	return __f2fs_get_acl(inode, type, NULL);
 }
 
diff --git a/fs/f2fs/acl.h b/fs/f2fs/acl.h
index 986fd1bc780b..3b7b0deb2845 100644
--- a/fs/f2fs/acl.h
+++ b/fs/f2fs/acl.h
@@ -33,7 +33,7 @@ struct f2fs_acl_header {
 
 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 
-extern struct posix_acl *f2fs_get_acl(struct inode *, int);
+extern struct posix_acl *f2fs_get_acl(struct inode *, int, int);
 extern int f2fs_set_acl(struct user_namespace *, struct inode *,
 			struct posix_acl *, int);
 extern int f2fs_init_acl(struct inode *, struct inode *, struct page *,
diff --git a/fs/fuse/acl.c b/fs/fuse/acl.c
index 52b165319be1..194cb81634f9 100644
--- a/fs/fuse/acl.c
+++ b/fs/fuse/acl.c
@@ -11,7 +11,7 @@
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
 
-struct posix_acl *fuse_get_acl(struct inode *inode, int type)
+struct posix_acl *fuse_get_acl(struct inode *inode, int type, int flags)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	int size;
@@ -19,6 +19,9 @@ struct posix_acl *fuse_get_acl(struct inode *inode, int type)
 	void *value = NULL;
 	struct posix_acl *acl;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	if (fuse_is_bad(inode))
 		return ERR_PTR(-EIO);
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 07829ce78695..ba3a419c6766 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1216,7 +1216,7 @@ extern const struct xattr_handler *fuse_acl_xattr_handlers[];
 extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
 
 struct posix_acl;
-struct posix_acl *fuse_get_acl(struct inode *inode, int type);
+struct posix_acl *fuse_get_acl(struct inode *inode, int type, int flags);
 int fuse_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		 struct posix_acl *acl, int type);
 
diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
index 9165d70ead07..956132de223c 100644
--- a/fs/gfs2/acl.c
+++ b/fs/gfs2/acl.c
@@ -57,13 +57,16 @@ static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
 	return acl;
 }
 
-struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
+struct posix_acl *gfs2_get_acl(struct inode *inode, int type, int flags)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder gh;
 	bool need_unlock = false;
 	struct posix_acl *acl;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
 		int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
 					     LM_FLAG_ANY, &gh);
diff --git a/fs/gfs2/acl.h b/fs/gfs2/acl.h
index eccc6a43326c..cdf8f12089de 100644
--- a/fs/gfs2/acl.h
+++ b/fs/gfs2/acl.h
@@ -11,7 +11,7 @@
 
 #define GFS2_ACL_MAX_ENTRIES(sdp) ((300 << (sdp)->sd_sb.sb_bsize_shift) >> 12)
 
-extern struct posix_acl *gfs2_get_acl(struct inode *inode, int type);
+extern struct posix_acl *gfs2_get_acl(struct inode *inode, int type, int flags);
 extern int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 extern int gfs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 			struct posix_acl *acl, int type);
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
index 55a79df70d24..35f4a0dcbd71 100644
--- a/fs/jffs2/acl.c
+++ b/fs/jffs2/acl.c
@@ -173,12 +173,15 @@ static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
 	return ERR_PTR(-EINVAL);
 }
 
-struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type, int flags)
 {
 	struct posix_acl *acl;
 	char *value = NULL;
 	int rc, xprefix;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
diff --git a/fs/jffs2/acl.h b/fs/jffs2/acl.h
index 62c50da9d493..afd6f924aacb 100644
--- a/fs/jffs2/acl.h
+++ b/fs/jffs2/acl.h
@@ -27,7 +27,7 @@ struct jffs2_acl_header {
 
 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 
-struct posix_acl *jffs2_get_acl(struct inode *inode, int type);
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type, int flags);
 int jffs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		  struct posix_acl *acl, int type);
 extern int jffs2_init_acl_pre(struct inode *, struct inode *, umode_t *);
diff --git a/fs/jfs/acl.c b/fs/jfs/acl.c
index 43c285c3d2a7..344d047bcb97 100644
--- a/fs/jfs/acl.c
+++ b/fs/jfs/acl.c
@@ -14,13 +14,16 @@
 #include "jfs_xattr.h"
 #include "jfs_acl.h"
 
-struct posix_acl *jfs_get_acl(struct inode *inode, int type)
+struct posix_acl *jfs_get_acl(struct inode *inode, int type, int flags)
 {
 	struct posix_acl *acl;
 	char *ea_name;
 	int size;
 	char *value = NULL;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch(type) {
 		case ACL_TYPE_ACCESS:
 			ea_name = XATTR_NAME_POSIX_ACL_ACCESS;
diff --git a/fs/jfs/jfs_acl.h b/fs/jfs/jfs_acl.h
index 7ae389a7a366..e86997d1f123 100644
--- a/fs/jfs/jfs_acl.h
+++ b/fs/jfs/jfs_acl.h
@@ -7,7 +7,7 @@
 
 #ifdef CONFIG_JFS_POSIX_ACL
 
-struct posix_acl *jfs_get_acl(struct inode *inode, int type);
+struct posix_acl *jfs_get_acl(struct inode *inode, int type, int flags);
 int jfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		struct posix_acl *acl, int type);
 int jfs_init_acl(tid_t, struct inode *, struct inode *);
diff --git a/fs/nfs/nfs3_fs.h b/fs/nfs/nfs3_fs.h
index c8a192802dda..0f3ba2f3b8da 100644
--- a/fs/nfs/nfs3_fs.h
+++ b/fs/nfs/nfs3_fs.h
@@ -11,7 +11,7 @@
  * nfs3acl.c
  */
 #ifdef CONFIG_NFS_V3_ACL
-extern struct posix_acl *nfs3_get_acl(struct inode *inode, int type);
+extern struct posix_acl *nfs3_get_acl(struct inode *inode, int type, int flags);
 extern int nfs3_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 			struct posix_acl *acl, int type);
 extern int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
index 9ec560aa4a50..f94def1342c6 100644
--- a/fs/nfs/nfs3acl.c
+++ b/fs/nfs/nfs3acl.c
@@ -44,7 +44,7 @@ static void nfs3_abort_get_acl(struct posix_acl **p)
 	cmpxchg(p, sentinel, ACL_NOT_CACHED);
 }
 
-struct posix_acl *nfs3_get_acl(struct inode *inode, int type)
+struct posix_acl *nfs3_get_acl(struct inode *inode, int type, int flags)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 	struct page *pages[NFSACL_MAXPAGES] = { };
@@ -62,6 +62,9 @@ struct posix_acl *nfs3_get_acl(struct inode *inode, int type)
 	};
 	int status, count;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
 		return ERR_PTR(-EOPNOTSUPP);
 
diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
index 5c72a7e6d6c5..a4df6e30c017 100644
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -289,7 +289,7 @@ int ocfs2_iop_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 	return status;
 }
 
-struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
+struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type, int flags)
 {
 	struct ocfs2_super *osb;
 	struct buffer_head *di_bh = NULL;
@@ -297,6 +297,9 @@ struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
 	int had_lock;
 	struct ocfs2_lock_holder oh;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	osb = OCFS2_SB(inode->i_sb);
 	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
 		return NULL;
diff --git a/fs/ocfs2/acl.h b/fs/ocfs2/acl.h
index f59d8d0a61fa..e005c93b9153 100644
--- a/fs/ocfs2/acl.h
+++ b/fs/ocfs2/acl.h
@@ -16,7 +16,7 @@ struct ocfs2_acl_entry {
 	__le32 e_id;
 };
 
-struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type);
+struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type, int flags);
 int ocfs2_iop_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		      struct posix_acl *acl, int type);
 extern int ocfs2_acl_chmod(struct inode *, struct buffer_head *);
diff --git a/fs/orangefs/acl.c b/fs/orangefs/acl.c
index 18852b9ed82b..d93841d478ed 100644
--- a/fs/orangefs/acl.c
+++ b/fs/orangefs/acl.c
@@ -10,12 +10,15 @@
 #include "orangefs-bufmap.h"
 #include <linux/posix_acl_xattr.h>
 
-struct posix_acl *orangefs_get_acl(struct inode *inode, int type)
+struct posix_acl *orangefs_get_acl(struct inode *inode, int type, int flags)
 {
 	struct posix_acl *acl;
 	int ret;
 	char *key = NULL, *value = NULL;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		key = XATTR_NAME_POSIX_ACL_ACCESS;
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index 0e6b97682e41..370bd89c670f 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -106,7 +106,7 @@ enum orangefs_vfs_op_states {
 extern int orangefs_init_acl(struct inode *inode, struct inode *dir);
 extern const struct xattr_handler *orangefs_xattr_handlers[];
 
-extern struct posix_acl *orangefs_get_acl(struct inode *inode, int type);
+extern struct posix_acl *orangefs_get_acl(struct inode *inode, int type, int flags);
 extern int orangefs_set_acl(struct user_namespace *mnt_userns,
 			    struct inode *inode, struct posix_acl *acl,
 			    int type);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 5e828a1c98a8..727154a1d3ce 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -448,12 +448,15 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 	return res;
 }
 
-struct posix_acl *ovl_get_acl(struct inode *inode, int type)
+struct posix_acl *ovl_get_acl(struct inode *inode, int type, int flags)
 {
 	struct inode *realinode = ovl_inode_real(inode);
 	const struct cred *old_cred;
 	struct posix_acl *acl;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
 		return NULL;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 6ec73db4bf9e..daf6b75b9a54 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -485,7 +485,7 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 		  void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
-struct posix_acl *ovl_get_acl(struct inode *inode, int type);
+struct posix_acl *ovl_get_acl(struct inode *inode, int type, int flags);
 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index f3309a7edb49..6b7f793e2b6f 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -138,7 +138,7 @@ struct posix_acl *get_acl(struct inode *inode, int type)
 		set_cached_acl(inode, type, NULL);
 		return NULL;
 	}
-	acl = inode->i_op->get_acl(inode, type);
+	acl = inode->i_op->get_acl(inode, type, 0);
 
 	if (IS_ERR(acl)) {
 		/*
diff --git a/fs/reiserfs/acl.h b/fs/reiserfs/acl.h
index fd58618da360..bf10841b892d 100644
--- a/fs/reiserfs/acl.h
+++ b/fs/reiserfs/acl.h
@@ -48,7 +48,7 @@ static inline int reiserfs_acl_count(size_t size)
 }
 
 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
-struct posix_acl *reiserfs_get_acl(struct inode *inode, int type);
+struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, int flags);
 int reiserfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		     struct posix_acl *acl, int type);
 int reiserfs_acl_chmod(struct inode *inode);
diff --git a/fs/reiserfs/xattr_acl.c b/fs/reiserfs/xattr_acl.c
index a9547144a099..0fdb4f531098 100644
--- a/fs/reiserfs/xattr_acl.c
+++ b/fs/reiserfs/xattr_acl.c
@@ -190,13 +190,16 @@ static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * si
  * inode->i_mutex: down
  * BKL held [before 2.5.x]
  */
-struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
+struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, int flags)
 {
 	char *name, *value;
 	struct posix_acl *acl;
 	int size;
 	int retval;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = XATTR_NAME_POSIX_ACL_ACCESS;
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index d02bef24b32b..5f9b541e029d 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -125,7 +125,7 @@ xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 }
 
 struct posix_acl *
-xfs_get_acl(struct inode *inode, int type)
+xfs_get_acl(struct inode *inode, int type, int flags)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
@@ -137,6 +137,9 @@ xfs_get_acl(struct inode *inode, int type)
 	};
 	int			error;
 
+	if (flags)
+		return ERR_PTR(-EINVAL);
+
 	trace_xfs_get_acl(ip);
 
 	switch (type) {
diff --git a/fs/xfs/xfs_acl.h b/fs/xfs/xfs_acl.h
index 7bdb3a4ed798..38f933f2e281 100644
--- a/fs/xfs/xfs_acl.h
+++ b/fs/xfs/xfs_acl.h
@@ -10,13 +10,13 @@ struct inode;
 struct posix_acl;
 
 #ifdef CONFIG_XFS_POSIX_ACL
-extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);
+extern struct posix_acl *xfs_get_acl(struct inode *inode, int type, int flags);
 extern int xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		       struct posix_acl *acl, int type);
 extern int __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 void xfs_forget_acl(struct inode *inode, const char *name);
 #else
-static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type)
+static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type, int flags)
 {
 	return NULL;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 640574294216..1c56d4fc4efe 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2065,7 +2065,7 @@ struct inode_operations {
 	struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
 	const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
 	int (*permission) (struct user_namespace *, struct inode *, int);
-	struct posix_acl * (*get_acl)(struct inode *, int);
+	struct posix_acl * (*get_acl)(struct inode *, int, int);
 
 	int (*readlink) (struct dentry *, char __user *,int);
 
-- 
2.31.1

[PATCH 2/2] ovl: enable RCU'd ->get_acl()

[Miklos Szeredi]

Overlayfs does not cache ACL's (to avoid double caching).  Instead it just
calls the underlying filesystem's i_op->get_acl(), which will return the
cached value, if possible.

In rcu path walk, however, get_cached_acl_rcu() is employed to get the
value from the cache, which will fail on overlayfs resulting in dropping
out of rcu walk mode.  This can result in a big performance hit in certain
situations.

Fix by calling ->get_acl() with LOOKUP_RCU flag in case of ACL_DONT_CACHE
(which indicates pass-through)

Reported-by: garyhuang <zjh.20052005@163.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/inode.c | 7 ++++---
 fs/posix_acl.c       | 8 +++++++-
 include/linux/fs.h   | 5 +++++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 727154a1d3ce..6a55231b262a 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -13,6 +13,7 @@
 #include <linux/fiemap.h>
 #include <linux/fileattr.h>
 #include <linux/security.h>
+#include <linux/namei.h>
 #include "overlayfs.h"
 
 
@@ -454,12 +455,12 @@ struct posix_acl *ovl_get_acl(struct inode *inode, int type, int flags)
 	const struct cred *old_cred;
 	struct posix_acl *acl;
 
-	if (flags)
-		return ERR_PTR(-EINVAL);
-
 	if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
 		return NULL;
 
+	if (flags & LOOKUP_RCU)
+		return get_cached_acl_rcu(realinode, type);
+
 	old_cred = ovl_override_creds(inode->i_sb);
 	acl = get_acl(realinode, type);
 	revert_creds(old_cred);
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 6b7f793e2b6f..4d1c6c266cf0 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -22,6 +22,7 @@
 #include <linux/xattr.h>
 #include <linux/export.h>
 #include <linux/user_namespace.h>
+#include <linux/namei.h>
 
 static struct posix_acl **acl_by_type(struct inode *inode, int type)
 {
@@ -56,7 +57,12 @@ EXPORT_SYMBOL(get_cached_acl);
 
 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
 {
-	return rcu_dereference(*acl_by_type(inode, type));
+	struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type));
+
+	if (acl == ACL_DONT_CACHE)
+		acl = inode->i_op->get_acl(inode, type, LOOKUP_RCU);
+
+	return acl;
 }
 EXPORT_SYMBOL(get_cached_acl_rcu);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1c56d4fc4efe..20b7db2d0a85 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -581,6 +581,11 @@ static inline void mapping_allow_writable(struct address_space *mapping)
 
 struct posix_acl;
 #define ACL_NOT_CACHED ((void *)(-1))
+/*
+ * ACL_DONT_CACHE is for stacked filesystems, that rely on underlying fs to
+ * cache the ACL.  This also means that ->get_acl() can be called in RCU mode
+ * with the LOOKUP_RCU flag.
+ */
 #define ACL_DONT_CACHE ((void *)(-3))
 
 static inline struct posix_acl *
-- 
2.31.1

Re: [PATCH 2/2] ovl: enable RCU'd ->get_acl()

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2885 bytes --]

Hi Miklos,

I love your patch! Yet something to improve:

[auto build test ERROR on miklos-vfs/overlayfs-next]
[also build test ERROR on kdave/for-next ceph-client/for-linus xiang-erofs/dev-test ext4/dev f2fs/dev-test fuse/for-next gfs2/for-next linus/master v5.14-rc5 next-20210810]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Miklos-Szeredi/allow-overlayfs-to-do-RCU-lookups/20210810-200939
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next
config: hexagon-randconfig-r032-20210810 (attached as .config)
compiler: clang version 12.0.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/7303859328569bbf653d8350215cd37b79486626
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Miklos-Szeredi/allow-overlayfs-to-do-RCU-lookups/20210810-200939
        git checkout 7303859328569bbf653d8350215cd37b79486626
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

>> fs/overlayfs/inode.c:460:10: error: implicit declaration of function 'get_cached_acl_rcu' [-Werror,-Wimplicit-function-declaration]
                   return get_cached_acl_rcu(realinode, type);
                          ^
>> fs/overlayfs/inode.c:460:10: warning: incompatible integer to pointer conversion returning 'int' from a function with result type 'struct posix_acl *' [-Wint-conversion]
                   return get_cached_acl_rcu(realinode, type);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 1 error generated.


vim +/get_cached_acl_rcu +460 fs/overlayfs/inode.c

   449	
   450	struct posix_acl *ovl_get_acl(struct inode *inode, int type, int flags)
   451	{
   452		struct inode *realinode = ovl_inode_real(inode);
   453		const struct cred *old_cred;
   454		struct posix_acl *acl;
   455	
   456		if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
   457			return NULL;
   458	
   459		if (flags & LOOKUP_RCU)
 > 460			return get_cached_acl_rcu(realinode, type);
   461	
   462		old_cred = ovl_override_creds(inode->i_sb);
   463		acl = get_acl(realinode, type);
   464		revert_creds(old_cred);
   465	
   466		return acl;
   467	}
   468	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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