On Friday 12 December 2008 01:56, OGAWA Hirofumi wrote:

quoted text
> ...Just FYI for people, probably you know though,

> inode->i_size has race on 32bit arch. It is 64bit value, so,

>

> 	*size += blocksize;

>

> means something like the following. E.g.

>

> 	load 0x0(size), %reg1

> 	load 0x4(size), %reg2

>         add blocksize, %reg1

>         add-carry %reg2

> 	store %reg1, 0x0(size)

>         			<---- (W)

> 	store %reg2, 0x4(size)

>

> So, block I/O library like block_write_full_page() can read the size at

> (W) point. The result may be bogus size.

>

> We have to fix this later, maybe change with phtree. (don't read i_size

> without lock, or use i_size_read()/i_size_write())

Ah, I thought about that when you mentioned it earlier and forgot to

take care of it in my patch.  Something like this:
loff_t tux_create_entry(struct inode *dir, const char *name, int len, inum_t inum, unsigned mode)

{

	loff_t size = i_size_read(dir);

	int err = _tux_create_entry(dir, name, len, inum, mode, &size);

	i_size_write(dir, size);

	return err;

}
Regards,
Daniel
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