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>

1 files changed, 25 insertions, 55 deletions

diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 5becc6a3ff8c..9cdf7dc4d5cb 100644
--- 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);