ocfs2: split transactions in dio completion to avoid credit exhaustion

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: split transactions in dio completion to avoid credit exhaustion

During ocfs2 dio operations, JBD2 may report warnings via following

call trace:

ocfs2_dio_end_io_write

ocfs2_mark_extent_written

ocfs2_change_extent_flag

ocfs2_split_extent

ocfs2_try_to_merge_extent

ocfs2_extend_rotate_transaction

ocfs2_extend_trans

jbd2__journal_restart

start_this_handle

output: JBD2: kworker/6:2 wants too many credits credits:5450 rsv_credits:0 max:5449

To prevent exceeding the credits limit, modify ocfs2_dio_end_io_write() to

handle extents in a batch of transaction.

Additionally, relocate ocfs2_del_inode_from_orphan(). The orphan inode

should only be removed from the orphan list after the extent tree update

is complete. This ensures that if a crash occurs in the middle of extent

tree updates, we won't leave stale blocks beyond EOF.

This patch also changes the logic for updating the inode size and removing

orphan, making it similar to ext4_dio_write_end_io(). Both operations are

performed only when everything looks good.

Finally, thanks to Jans and Joseph for providing the bug fix prototype and

suggestions.