writev/readv dnotify confusion
hi,
not sure if dnotify is handled by writev/readv correctly,
below are some code of do_readv_writev() in linux/fs/read_write.c:
out_nofree:
/* VERIFY_WRITE actually means a read, as we write to user space */
if ((ret + (type == VERIFY_WRITE)) > 0)
dnotify_parent(file->f_dentry,
(type == VERIFY_WRITE) ? DN_MODIFY : DN_ACCESS);
return ret;
}based on this code, it seems writev() sets DN_ACCESS while readv() sets DN_MODIFY.
i have also verified this by writing a testing program, in my testing program, if just do fcntl(fd, F_NOTIFY, DN_MODIFY), on signal is raised after a writev(), if i do fcntl(fd, F_NOTIFY, DN_ACCESS), then get the signal.
so wonder maybe the code above should be modified as something like:
out_nofree:
/* VERIFY_WRITE actually means a read, as we write to user space */
if ((ret + (type == VERIFY_WRITE)) > 0)
dnotify_parent(file->f_dentry,
(type == VERIFY_WRITE) ? DN_ACCESS : DN_MODIFY);
return ret;
}cheers,