ext4: big update

from
"2011-08-12	ext4: Properly count journal credits for long symlinks"
until
"2011-10-25	ext4: remove messy logic from ext4_ext_rm_leaf"

https://git.kernel.org/cgit/linux/kernel/git/tytso/ext4.git/log/?h=for_linus_urgent&qt=grep&q=ext4&ofs=1050
https://git.kernel.org/cgit/linux/kernel/git/tytso/ext4.git/log/?h=for_linus_urgent&qt=grep&q=ext4&ofs=1000