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,
+};