On Wed, 2008-10-08 at 10:32 +0200, Eric Dumazet wrote: > About dup() syscall, it wont help, since old and new descriptor points to > the same "struct file", definitly sharing file position, since first Unixes. > > To quote the fine manual : > > After successful return of dup or dup2, the old and new descriptors may > be used interchangeably. They share locks, file position pointers and > flags; for example, if the file position is modified by using lseek on > one of the descriptors, the position is also changed for the other. Ah, ok. I'll try to remember for next time I write a multi-threaded user app (which given the size of my kernel todo list won't be any time soon I guess ;-) > pread()/pwrite() are used my multi-threaded applications that want to share > a single "struct file". Yeah, pread/pwrite is good. > Or they must use some form of synchronization around > regular read()/write()/lseek() calls. > > There is no generic f_pos race, only buggy applications. Agreed. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
