make generic_acl slightly more generic

Now that we cache the ACL pointers in the generic inode all the generic_acl
cruft can go away and generic_acl.c can directly implement xattr handlers
dealing with the full Posix ACL semantics for in-memory filesystems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 89 insertions, 69 deletions

diff --git a/fs/generic_acl.c b/fs/generic_acl.c
index e0b53aa7bbec..55458031e501 100644
--- a/fs/generic_acl.c
+++ b/fs/generic_acl.c
@@ -1,62 +1,58 @@
 /*
- * fs/generic_acl.c
- *
  * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
  *
  * This file is released under the GPL.
+ *
+ * Generic ACL support for in-memory filesystems.
  */
 
 #include <linux/sched.h>
 #include <linux/fs.h>
 #include <linux/generic_acl.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
 
-/**
- * generic_acl_list  -  Generic xattr_handler->list() operation
- * @ops:	Filesystem specific getacl and setacl callbacks
- */
-size_t
-generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
-		 int type, char *list, size_t list_size)
+
+static size_t
+generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
 {
 	struct posix_acl *acl;
-	const char *name;
+	const char *xname;
 	size_t size;
 
-	acl = ops->getacl(inode, type);
+	acl = get_cached_acl(dentry->d_inode, type);
 	if (!acl)
 		return 0;
 	posix_acl_release(acl);
 
-	switch(type) {
-		case ACL_TYPE_ACCESS:
-			name = POSIX_ACL_XATTR_ACCESS;
-			break;
-
-		case ACL_TYPE_DEFAULT:
-			name = POSIX_ACL_XATTR_DEFAULT;
-			break;
-
-		default:
-			return 0;
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xname = POSIX_ACL_XATTR_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		xname = POSIX_ACL_XATTR_DEFAULT;
+		break;
+	default:
+		return 0;
 	}
-	size = strlen(name) + 1;
+	size = strlen(xname) + 1;
 	if (list && size <= list_size)
-		memcpy(list, name, size);
+		memcpy(list, xname, size);
 	return size;
 }
 
-/**
- * generic_acl_get  -  Generic xattr_handler->get() operation
- * @ops:	Filesystem specific getacl and setacl callbacks
- */
-int
-generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
-		int type, void *buffer, size_t size)
+static int
+generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
+		     size_t size, int type)
 {
 	struct posix_acl *acl;
 	int error;
 
-	acl = ops->getacl(inode, type);
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+
+	acl = get_cached_acl(dentry->d_inode, type);
 	if (!acl)
 		return -ENODATA;
 	error = posix_acl_to_xattr(acl, buffer, size);
@@ -65,17 +61,16 @@ generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
 	return error;
 }
 
-/**
- * generic_acl_set  -  Generic xattr_handler->set() operation
- * @ops:	Filesystem specific getacl and setacl callbacks
- */
-int
-generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
-		int type, const void *value, size_t size)
+static int
+generic_acl_set(struct dentry *dentry, const char *name, const void *value,
+		     size_t size, int flags, int type)
 {
+	struct inode *inode = dentry->d_inode;
 	struct posix_acl *acl = NULL;
 	int error;
 
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;
 	if (!is_owner_or_cap(inode))
@@ -91,28 +86,27 @@ generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
 		error = posix_acl_valid(acl);
 		if (error)
 			goto failed;
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				mode = inode->i_mode;
-				error = posix_acl_equiv_mode(acl, &mode);
-				if (error < 0)
-					goto failed;
-				inode->i_mode = mode;
-				if (error == 0) {
-					posix_acl_release(acl);
-					acl = NULL;
-				}
-				break;
-
-			case ACL_TYPE_DEFAULT:
-				if (!S_ISDIR(inode->i_mode)) {
-					error = -EINVAL;
-					goto failed;
-				}
-				break;
+		switch (type) {
+		case ACL_TYPE_ACCESS:
+			mode = inode->i_mode;
+			error = posix_acl_equiv_mode(acl, &mode);
+			if (error < 0)
+				goto failed;
+			inode->i_mode = mode;
+			if (error == 0) {
+				posix_acl_release(acl);
+				acl = NULL;
+			}
+			break;
+		case ACL_TYPE_DEFAULT:
+			if (!S_ISDIR(inode->i_mode)) {
+				error = -EINVAL;
+				goto failed;
+			}
+			break;
 		}
 	}
-	ops->setacl(inode, type, acl);
+	set_cached_acl(inode, type, acl);
 	error = 0;
 failed:
 	posix_acl_release(acl);
@@ -121,14 +115,12 @@ failed:
 
 /**
  * generic_acl_init  -  Take care of acl inheritance at @inode create time
- * @ops:	Filesystem specific getacl and setacl callbacks
  *
  * Files created inside a directory with a default ACL inherit the
  * directory's default ACL.
  */
 int
-generic_acl_init(struct inode *inode, struct inode *dir,
-		 struct generic_acl_operations *ops)
+generic_acl_init(struct inode *inode, struct inode *dir)
 {
 	struct posix_acl *acl = NULL;
 	mode_t mode = inode->i_mode;
@@ -136,7 +128,7 @@ generic_acl_init(struct inode *inode, struct inode *dir,
 
 	inode->i_mode = mode & ~current_umask();
 	if (!S_ISLNK(inode->i_mode))
-		acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
+		acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
 	if (acl) {
 		struct posix_acl *clone;
 
@@ -145,7 +137,7 @@ generic_acl_init(struct inode *inode, struct inode *dir,
 			error = -ENOMEM;
 			if (!clone)
 				goto cleanup;
-			ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
+			set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
 			posix_acl_release(clone);
 		}
 		clone = posix_acl_clone(acl, GFP_KERNEL);
@@ -156,7 +148,7 @@ generic_acl_init(struct inode *inode, struct inode *dir,
 		if (error >= 0) {
 			inode->i_mode = mode;
 			if (error > 0)
-				ops->setacl(inode, ACL_TYPE_ACCESS, clone);
+				set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
 		}
 		posix_acl_release(clone);
 	}
@@ -169,20 +161,19 @@ cleanup:
 
 /**
  * generic_acl_chmod  -  change the access acl of @inode upon chmod()
- * @ops:	FIlesystem specific getacl and setacl callbacks
  *
  * A chmod also changes the permissions of the owner, group/mask, and
  * other ACL entries.
  */
 int
-generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
+generic_acl_chmod(struct inode *inode)
 {
 	struct posix_acl *acl, *clone;
 	int error = 0;
 
 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;
-	acl = ops->getacl(inode, ACL_TYPE_ACCESS);
+	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
 	if (acl) {
 		clone = posix_acl_clone(acl, GFP_KERNEL);
 		posix_acl_release(acl);
@@ -190,8 +181,37 @@ generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
 			return -ENOMEM;
 		error = posix_acl_chmod_masq(clone, inode->i_mode);
 		if (!error)
-			ops->setacl(inode, ACL_TYPE_ACCESS, clone);
+			set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
 		posix_acl_release(clone);
 	}
 	return error;
 }
+
+int
+generic_check_acl(struct inode *inode, int mask)
+{
+	struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
+
+	if (acl) {
+		int error = posix_acl_permission(inode, acl, mask);
+		posix_acl_release(acl);
+		return error;
+	}
+	return -EAGAIN;
+}
+
+struct xattr_handler generic_acl_access_handler = {
+	.prefix = POSIX_ACL_XATTR_ACCESS,
+	.flags	= ACL_TYPE_ACCESS,
+	.list	= generic_acl_list,
+	.get	= generic_acl_get,
+	.set	= generic_acl_set,
+};
+
+struct xattr_handler generic_acl_default_handler = {
+	.prefix = POSIX_ACL_XATTR_DEFAULT,
+	.flags	= ACL_TYPE_DEFAULT,
+	.list	= generic_acl_list,
+	.get	= generic_acl_get,
+	.set	= generic_acl_set,
+};