fsal_truncate.c

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/*
 * vim:expandtab:shiftwidth=8:tabstop=8:
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "fsal.h"
#include "fsal_internal.h"
#include "fsal_convert.h"

fsal_status_t ZFSFSAL_truncate(fsal_handle_t * filehandle, /* IN */
                            fsal_op_context_t * p_context,      /* IN */
                            fsal_size_t length, /* IN */
                            fsal_file_t * file_descriptor,      /* Unused in this FSAL */
                            fsal_attrib_list_t * object_attributes      /* [ IN/OUT ] */
    )
{
  int rc;
  creden_t cred;

  /* sanity checks.
   * note : object_attributes is optional.
   */
  if(!filehandle || !p_context)
    Return(ERR_FSAL_FAULT, 0, INDEX_FSAL_truncate);

  /* >> check object type if it's stored into the filehandle << */
  if(((zfsfsal_handle_t *)filehandle)->data.type != FSAL_TYPE_FILE)
      Return(ERR_FSAL_INVAL, 0, INDEX_FSAL_truncate);

  /* Hook to prevent any modification in a snapshot */
  if(((zfsfsal_handle_t *)filehandle)->data.i_snap != 0)
  {
    LogDebug(COMPONENT_FSAL, "Trying to truncate a file inside a snapshot");
    Return(ERR_FSAL_ROFS, 0, INDEX_FSAL_truncate);
  }

  cred.uid = p_context->credential.user;
  cred.gid = p_context->credential.group;

  TakeTokenFSCall();

  rc = libzfswrap_truncate(((zfsfsal_op_context_t *)p_context)->export_context->p_vfs,
                           &cred,
                           ((zfsfsal_handle_t *)filehandle)->data.zfs_handle, length);

  ReleaseTokenFSCall();

  /* >> interpret error code << */
  if(rc)
    Return(posix2fsal_error(rc), 0, INDEX_FSAL_truncate);

  /* >> Optionaly retrieve post op attributes
   * If your filesystem truncate call can't return them,
   * you can proceed like this : <<
   */
  if(object_attributes)
    {

      fsal_status_t st;

      st = ZFSFSAL_getattrs(filehandle, p_context, object_attributes);

      if(FSAL_IS_ERROR(st))
        {
          FSAL_CLEAR_MASK(object_attributes->asked_attributes);
          FSAL_SET_MASK(object_attributes->asked_attributes, FSAL_ATTR_RDATTR_ERR);
        }

    }

  /* No error occured */
  Return(ERR_FSAL_NO_ERROR, 0, INDEX_FSAL_truncate);

}