This could have been made as part of the merge in r2661.

ibuf_rec_get_info(): Eliminate the local variable "mod".  Use switch-case
instead of if-else if-else.

ibuf_rec_get_op_type(), ibuf_add_ops(), ibuf_print_ops():
Add const qualifiers to read-only parameters.

ibuf_rec_get_volume(): Remove empty line at end of block.

Comment the assignment to btr_cur->thr.

error.  In r2324, when changes were merged from branches/fts, the
assignment guess = NULL was accidentally removed after height--.
The assignment is in that place in branches/fts since r990.

flag to row_search_index_entry() when there are no foreign key
constraints.  This flag was accidentally omitted when the delete buffering
was merged from branches/fts in r2324, and thus delete marking was never
buffered.

suspicious assignment that was removed in r2670 and note why it is needed.

insert buffer bitmap.

assignment that was added in r990 to branches/fts and merged in r2324.

ibuf_rec_get_counter(): Rename from ibuf_rec_get_fake_counter().  There is
nothing fake about the counter.  Also add const qualifiers to the pointers.

assertion.

instead of accessing index->type directly.

buf_pool_mutex directly.

buf_pool->watch_ fields to start with the common prefix buf_pool_watch,
so that they can be searched easily:

buf_pool_watch_set(): Renamed from buf_pool_add_watch().  The "add" was
misleading, because only one watch can be active at a time.

buf_pool_watch_clear(): Renamed from buf_pool_remove_watch().

buf_pool_watch_occurred(): Renamed from buf_pool_watch_happened().

missing since the code was merged in r2324 from branches/fts.

and merged in r2324:

ibuf_page(): Assert that recv_no_ibuf_operations == FALSE.

fil_io(): Check !recv_no_ibuf_operations before calling ibuf_page().

buf_page_get_gen(): Once again, zip_size must always match the
compressed page size of the tablespace where the page is requested from.
This seems to hold also for all calls from the insert buffer.

buf_page_optimistic_get_func(): Do not pass mtr to ibuf_page(), because
there is no guarantee that mtr would contain an x-latch to the insert
buffer bitmap page that covers (block->page.space, block->page.offset).

zip_size should always equal fil_space_get_zip_size(space), even when called
from ibuf.

ibuf_page() should be called with mtr=NULL to be equivalent to the original
implementation.  We cannot assume that mtr holds an x-latch on the insert
buffer bitmap page that covers the page that is being requested.

differ from branches/zip.

so that this will be identical to branches/zip.

differences from branches/zip.  The __attribute__((unused)) should
work on all platforms.  When compiled with something else than GCC,
MySQL supposedly does #define __attribute__(x) /* empty */
so that the attributes will be ignored.

from branches/zip.

btr_cur_optimistic_delete(): Split a too long line in the way it is
split in branches/zip.

buf_page_get_gen(): Add missing space in the function comment.

buf_print_io(): Restoer a removed space to the printout.

univ.i: Remove C++-style (or C99-style) comments.

buf0buf.h: Undo the white-space changes to the wrapper macros of
buf_page_get_gen().

ibuf_update_free_bits_low(): Revert the changes.  Restore the assertion
that this function must not be invoked on compressed pages.  The function
ibuf_update_free_bits_zip() is for compressed pages.

ibuf_insert_to_index_page(): Undo a white-space change.

accessing a freed record on a compressed page.

The variable srv_stats_sample_pages was declared ib_uint64_t in srv0srv.c
and unsigned long long in srv0srv.h.

the file differ from branches/zip.

btr0cur.c: Undo changes to white space that make the code differ from
branches/zip.

btr_cur_del_unmark_for_ibuf(): Remove this unused function.

btr_cur_set_deleted_flag_for_ibuf(): Add missing UNIV_INTERN specifier.
Correct the function comment.  Call btr_rec_set_deleted_flag() instead
of rec_set_deleted_flag_new(), so that delete buffering will actually
work on ROW_FORMAT=REDUNDANT tables.

closer to branches/zip.

ibuf_size_update(): Add const qualifier to the parameter "root".
Remove #ifdef UNIV_SYNC_DEBUG around ut_ad(mutex_own()).

ibuf_page(): Use the variable name local_mtr instead of mtr_local, to
be more like existing functions.  Eliminate the flag use_local_mtr.

ibuf_get_merge_page_nos(): Restore an "if (...) break; else if" to
"if (...) break; if" as in branches/zip.

ibuf_dummy_index_create(), ibuf_dummy_index_add_col(),
ibuf_contract_ext(), ibuf_insert_low(): Revert to the formatting of
branches/zip.

ibuf_print(): Do not print n_ops[].

ibuf_print_ops(): Output trailing newline.

to eliminate double negation from an assertion.

The followin mysql-tests failed (and they are known to fail):
main.information_schema        	[ fail ]
main.innodb_file_per_table_basic[ fail ]
main.type_bit_innodb           	[ fail ]

Tested against : MYSQL_SERVER_VERSION  "5.1.28"

zip size can be 0.