jfs: use generic posix ACL infrastructure

Copy the scheme I introduced to btrfs many years ago to only use the
xattr handler for ACLs, but pass plain attrs straight through.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 38 insertions, 70 deletions

diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index d3472f4cd530..5324e4e2b992 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -666,81 +666,12 @@ static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
 }
 
 /*
- * can_set_system_xattr
- *
- * This code is specific to the system.* namespace.  It contains policy
- * which doesn't belong in the main xattr codepath.
- */
-static int can_set_system_xattr(struct inode *inode, const char *name,
-                                const void *value, size_t value_len)
-{
-#ifdef CONFIG_JFS_POSIX_ACL
-        struct posix_acl *acl;
-        int rc;
-
-        if (!inode_owner_or_capable(inode))
-                return -EPERM;
-
-        /*
-         * POSIX_ACL_XATTR_ACCESS is tied to i_mode
-         */
-        if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
-                acl = posix_acl_from_xattr(&init_user_ns, value, value_len);
-                if (IS_ERR(acl)) {
-                        rc = PTR_ERR(acl);
-                        printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
-                               rc);
-                        return rc;
-                }
-                if (acl) {
-                        rc = posix_acl_equiv_mode(acl, &inode->i_mode);
-                        posix_acl_release(acl);
-                        if (rc < 0) {
-                                printk(KERN_ERR
-                                       "posix_acl_equiv_mode returned %d\n",
-                                       rc);
-                                return rc;
-                        }
-                        mark_inode_dirty(inode);
-                }
-                /*
-                 * We're changing the ACL.  Get rid of the cached one
-                 */
-                forget_cached_acl(inode, ACL_TYPE_ACCESS);
-
-                return 0;
-        } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
-                acl = posix_acl_from_xattr(&init_user_ns, value, value_len);
-                if (IS_ERR(acl)) {
-                        rc = PTR_ERR(acl);
-                        printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
-                               rc);
-                        return rc;
-                }
-                posix_acl_release(acl);
-
-                /*
-                 * We're changing the default ACL.  Get rid of the cached one
-                 */
-                forget_cached_acl(inode, ACL_TYPE_DEFAULT);
-
-                return 0;
-        }
-#endif                  /* CONFIG_JFS_POSIX_ACL */
-        return -EOPNOTSUPP;
-}
-
-/*
  * Most of the permission checking is done by xattr_permission in the vfs.
- * The local file system is responsible for handling the system.* namespace.
  * We also need to verify that this is a namespace that we recognize.
  */
 static int can_set_xattr(struct inode *inode, const char *name,
                          const void *value, size_t value_len)
 {
-        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
-                return can_set_system_xattr(inode, name, value, value_len);
-
         if (!strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) {
                 /*
                  * This makes sure that we aren't trying to set an
@@ -748,7 +679,7 @@ static int can_set_xattr(struct inode *inode, const char *name,
                  * with "os2."
                  */
                 if (is_known_namespace(name + XATTR_OS2_PREFIX_LEN))
-                                return -EOPNOTSUPP;
+                        return -EOPNOTSUPP;
                 return 0;
         }
 
@@ -913,6 +844,14 @@ int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
         if ((rc = can_set_xattr(inode, name, value, value_len)))
                 return rc;
 
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_setxattr(dentry, name, value, value_len, flags);
+
         if (value == NULL) {    /* empty EA, do not remove */
                 value = "";
                 value_len = 0;
@@ -986,6 +925,14 @@ ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
 {
         int err;
 
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_getxattr(dentry, name, data, buf_size);
+
         if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
                 /*
                  * skip past "os2." prefix
@@ -1077,6 +1024,14 @@ int jfs_removexattr(struct dentry *dentry, const char *name)
         if ((rc = can_set_xattr(inode, name, NULL, 0)))
                 return rc;
 
+        /*
+         * If this is a request for a synthetic attribute in the system.*
+         * namespace use the generic infrastructure to resolve a handler
+         * for it via sb->s_xattr.
+         */
+        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+                return generic_removexattr(dentry, name);
+
         tid = txBegin(inode->i_sb, 0);
         mutex_lock(&ji->commit_mutex);
         rc = __jfs_setxattr(tid, dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
@@ -1088,6 +1043,19 @@ int jfs_removexattr(struct dentry *dentry, const char *name)
         return rc;
 }
 
+/*
+ * List of handlers for synthetic system.* attributes.  All real ondisk
+ * attributes are handled directly.
+ */
+const struct xattr_handler *jfs_xattr_handlers[] = {
+#ifdef JFS_POSIX_ACL
+        &posix_acl_access_xattr_handler,
+        &posix_acl_default_xattr_handler,
+#endif
+        NULL,
+};
+
+
 #ifdef CONFIG_JFS_SECURITY
 static int jfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
                           void *fs_info)