jfs: Clean up xattr name mapping

Instead of stripping "os2." prefixes in __jfs_setxattr, make callers
strip them, as __jfs_getxattr already does.  With that change, use the
same name mapping function in jfs_{get,set,remove}xattr.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 5becc6a..9cdf7dc 100644 (file)
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -86,6 +86,14 @@ struct ea_buffer {
 #define EA_MALLOC      0x0008
 
 
+/*
+ * Mapping of on-disk attribute names: for on-disk attribute names with an
+ * unknown prefix (not "system.", "user.", "security.", or "trusted."), the
+ * prefix "os2." is prepended.  On the way back to disk, "os2." prefixes are
+ * stripped and we make sure that the remaining name does not start with one
+ * of the know prefixes.
+ */
+
 static int is_known_namespace(const char *name)
 {
        if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
@@ -97,29 +105,19 @@ static int is_known_namespace(const char *name)
        return true;
 }
 
-/*
- * These three routines are used to recognize on-disk extended attributes
- * that are in a recognized namespace.  If the attribute is not recognized,
- * "os2." is prepended to the name
- */
-static int is_os2_xattr(struct jfs_ea *ea)
-{
-       return !is_known_namespace(ea->name);
-}
-
 static inline int name_size(struct jfs_ea *ea)
 {
-       if (is_os2_xattr(ea))
-               return ea->namelen + XATTR_OS2_PREFIX_LEN;
-       else
+       if (is_known_namespace(ea->name))
                return ea->namelen;
+       else
+               return ea->namelen + XATTR_OS2_PREFIX_LEN;
 }
 
 static inline int copy_name(char *buffer, struct jfs_ea *ea)
 {
        int len = ea->namelen;
 
-       if (is_os2_xattr(ea)) {
+       if (!is_known_namespace(ea->name)) {
                memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN);
                buffer += XATTR_OS2_PREFIX_LEN;
                len += XATTR_OS2_PREFIX_LEN;
@@ -669,29 +667,24 @@ static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
  * Most of the permission checking is done by xattr_permission in the vfs.
  * 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)
+static bool map_name_to_disk(const char **name)
 {
-       if (!strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) {
+       if (!strncmp(*name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) {
                /*
                 * This makes sure that we aren't trying to set an
                 * attribute in a different namespace by prefixing it
                 * with "os2."
                 */
-               if (is_known_namespace(name + XATTR_OS2_PREFIX_LEN))
-                       return -EOPNOTSUPP;
-               return 0;
+               if (is_known_namespace(*name + XATTR_OS2_PREFIX_LEN))
+                       return false;
+               *name += XATTR_OS2_PREFIX_LEN;
+               return true;
        }
 
        /*
         * Don't allow setting an attribute in an unknown namespace.
         */
-       if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
-           strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
-           strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
-               return -EOPNOTSUPP;
-
-       return 0;
+       return is_known_namespace(*name);
 }
 
 int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
@@ -704,21 +697,10 @@ int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
        int xattr_size;
        int new_size;
        int namelen = strlen(name);
-       char *os2name = NULL;
        int found = 0;
        int rc;
        int length;
 
-       if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
-               os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
-                                 GFP_KERNEL);
-               if (!os2name)
-                       return -ENOMEM;
-               strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
-               name = os2name;
-               namelen -= XATTR_OS2_PREFIX_LEN;
-       }
-
        down_write(&JFS_IP(inode)->xattr_sem);
 
        xattr_size = ea_get(inode, &ea_buf, 0);
@@ -841,8 +823,6 @@ int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
       out:
        up_write(&JFS_IP(inode)->xattr_sem);
 
-       kfree(os2name);
-
        return rc;
 }
 
@@ -862,8 +842,8 @@ int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
                return generic_setxattr(dentry, name, value, value_len, flags);
 
-       if ((rc = can_set_xattr(inode, name, value, value_len)))
-               return rc;
+       if (!map_name_to_disk(&name))
+               return -EOPNOTSUPP;
 
        if (value == NULL) {    /* empty EA, do not remove */
                value = "";
@@ -946,18 +926,8 @@ ssize_t jfs_getxattr(struct dentry *dentry, struct inode *inode,
        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
                return generic_getxattr(dentry, inode, name, data, buf_size);
 
-       if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
-               /*
-                * skip past "os2." prefix
-                */
-               name += XATTR_OS2_PREFIX_LEN;
-               /*
-                * Don't allow retrieving properly prefixed attributes
-                * by prepending them with "os2."
-                */
-               if (is_known_namespace(name))
-                       return -EOPNOTSUPP;
-       }
+       if (!map_name_to_disk(&name))
+               return -EOPNOTSUPP;
 
        err = __jfs_getxattr(inode, name, data, buf_size);
 
@@ -1042,8 +1012,8 @@ int jfs_removexattr(struct dentry *dentry, const char *name)
        if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
                return generic_removexattr(dentry, name);
 
-       if ((rc = can_set_xattr(inode, name, NULL, 0)))
-               return rc;
+       if (!map_name_to_disk(&name))
+               return -EOPNOTSUPP;
 
        tid = txBegin(inode->i_sb, 0);
        mutex_lock(&ji->commit_mutex);