[PATCH] ext3_get_blocks: support multiple blocks allocation in ext3_new_block()

Change ext3_try_to_allocate() (called via ext3_new_blocks()) to try to
allocate the requested number of blocks on a best effort basis: After
allocated the first block, it will always attempt to allocate the next few(up
to the requested size and not beyond the reservation window) adjacent blocks
at the same time.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>