On 12/11/2012 01:12 PM, Theodore Ts'o wrote: > On Tue, Dec 11, 2012 at 10:25:37AM +0800, Tao Ma wrote: >> uh, in sparc, we don't have empty_zero_page? I just want to create an >> inline data file without allocating a buffer with the specified length. >> So maybe I have to do the kzalloc thing then. :( > > Yeah, sparc64 apparently doesn't have empty_zero_page. All > architectures have ZERO_PAGE(0), which is what the DIO code uses, but > you can't count on it being mapped. > > What we could do instead is pass in a value of "(void *) -1", and then > in ext4_xattr_set_entry(), if i->value is -1, use memset to zero out > the value instead of memcpy. This will be safe for all architectures, > since we already use casts of negative values for ERR_PTR. > > In fact, we could just use "i.value = ERR_PTR(-1)" and > "IS_ERR_VALUE(i->value)", but it would be clearer to explicitly define > EXT4_ZERO_XATTR_VALUE to be "((void *) -1)", and use that to indicate > that ext4_xattr_set_entry() should zero out the page in question. yeah, that should saves us a lot in case of inline data creation and updating. I will change it. Thanks for the good advice. Thanks Tao -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
