mm: change invalidatepage prototype to accept length

Currently there is no way to truncate partial page where the end
truncate point is not at the end of the page. This is because it was not
needed and the functionality was enough for file system truncate
operation to work properly. However more file systems now support punch
hole feature and it can benefit from mm supporting truncating page just
up to the certain point.

Specifically, with this functionality truncate_inode_pages_range() can
be changed so it supports truncating partial page at the end of the
range (currently it will BUG_ON() if 'end' is not at the end of the
page).

This commit changes the invalidatepage() address space operation
prototype to accept range to be invalidated and update all the instances
for it.

We also change the block_invalidatepage() in the same way and actually
make a use of the new length argument implementing range invalidation.

Actual file system implementations will follow except the file systems
where the changes are really simple and should not change the behaviour
in any way .Implementation for truncate_page_range() which will be able
to accept page unaligned ranges will follow as well.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
jbd2: change jbd2_journal_invalidatepage to accept length

invalidatepage now accepts range to invalidate and there are two file
system using jbd2 also implementing punch hole feature which can benefit
from this. We need to implement the same thing for jbd2 layer in order to
allow those file system take benefit of this functionality.

This commit adds length argument to the jbd2_journal_invalidatepage()
and updates all instances in ext4 and ocfs2.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
ext4: use ->invalidatepage() length argument

->invalidatepage() aop now accepts range to invalidate so we can make
use of it in all ext4 invalidatepage routines.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Revert "ext4: remove no longer used functions in inode.c"

This reverts commit ccb4d7af914e0fe9b2f1022f8ea6c300463fd5e6.

This commit reintroduces functions ext4_block_truncate_page() and
ext4_block_zero_page_range() which has been previously removed in favour
of ext4_discard_partial_page_buffers().

In future commits we want to reintroduce those function and remove
ext4_discard_partial_page_buffers() since it is duplicating some code
and also partially duplicating work of truncate_pagecache_range(),
moreover the old implementation was much clearer.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: Call ext4_jbd2_file_inode() after zeroing block

In data=ordered mode we should call ext4_jbd2_file_inode() so that crash
after the truncate transaction has committed does not expose stall data
in the tail of the block.

Thanks Jan Kara for pointing that out.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Revert "ext4: fix fsx truncate failure"

This reverts commit 189e868fa8fdca702eb9db9d8afc46b5cb9144c9.

This commit reintroduces the use of ext4_block_truncate_page() in ext4
truncate operation instead of ext4_discard_partial_page_buffers().

The statement in the commit description that the truncate operation only
zero block unaligned portion of the last page is not exactly right,
since truncate_pagecache_range() also zeroes and invalidate the unaligned
portion of the page. Then there is no need to zero and unmap it once more
and ext4_block_truncate_page() was doing the right job, although we
still need to update the buffer head containing the last block, which is
exactly what ext4_block_truncate_page() is doing.

Moreover the problem described in the commit is fixed more properly with
commit

15291164b22a357cb211b618adfef4fa82fc0de3
	jbd2: clear BH_Delay & BH_Unwritten in journal_unmap_buffer

This was tested on ppc64 machine with block size of 1024 bytes without
any problems.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: truncate_inode_pages() in orphan cleanup path

Currently we do not tell mm to zero out tail of the page before truncate
in orphan_cleanup(). This is ok, because the page should not be
uptodate, however this may eventually change and I might cause problems.

Call truncate_inode_pages() as precautionary measure. Thanks Jan Kara
for pointing this out.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: use ext4_zero_partial_blocks in punch_hole

We're doing to get rid of ext4_discard_partial_page_buffers() since it is
duplicating some code and also partially duplicating work of
truncate_pagecache_range(), moreover the old implementation was much
clearer.

Now when the truncate_inode_pages_range() can handle truncating non page
aligned regions we can use this to invalidate and zero out block aligned
region of the punched out range and then use ext4_block_truncate_page()
to zero the unaligned blocks on the start and end of the range. This
will greatly simplify the punch hole code. Moreover after this commit we
can get rid of the ext4_discard_partial_page_buffers() completely.

We also introduce function ext4_prepare_punch_hole() to do come common
operations before we attempt to do the actual punch hole on
indirect or extent file which saves us some code duplication.

This has been tested on ppc64 with 1k block size with fsx and xfstests
without any problems.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: remove unused discard_partial_page_buffers

The discard_partial_page_buffers is no longer used anywhere so we can
simply remove it including the *_no_lock variant and
EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED define.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: remove unused code from ext4_remove_blocks()

The "head removal" branch in the condition is never used in any code
path in ext4 since the function only caller ext4_ext_rm_leaf() will make
sure that the extent is properly split before removing blocks. Note that
there is a bug in this branch anyway.

This commit removes the unused code completely and makes use of
ext4_error() instead of printk if dubious range is provided.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: update ext4_ext_remove_space trace point

Add "end" variable.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: make punch hole code path work with bigalloc

Currently punch hole is disabled in file systems with bigalloc
feature enabled. However the recent changes in punch hole patch should
make it easier to support punching holes on bigalloc enabled file
systems.

This commit changes partial_cluster handling in ext4_remove_blocks(),
ext4_ext_rm_leaf() and ext4_ext_remove_space(). Currently
partial_cluster is unsigned long long type and it makes sure that we
will free the partial cluster if all extents has been released from that
cluster. However it has been specifically designed only for truncate.

With punch hole we can be freeing just some extents in the cluster
leaving the rest untouched. So we have to make sure that we will notice
cluster which still has some extents. To do this I've changed
partial_cluster to be signed long long type. The only scenario where
this could be a problem is when cluster_size == block size, however in
that case there would not be any partial clusters so we're safe. For
bigger clusters the signed type is enough. Now we use the negative value
in partial_cluster to mark such cluster used, hence we know that we must
not free it even if all other extents has been freed from such cluster.

This scenario can be described in simple diagram:

|FFF...FF..FF.UUU|
 ^----------^
  punch hole

. - free space
| - cluster boundary
F - freed extent
U - used extent

Also update respective tracepoints to use signed long long type for
partial_cluster.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: suppress ext4 orphan messages on mount

Suppress the messages releating to processing the ext4 orphan list
("truncating inode" and "deleting unreferenced inode") unless the
debug option is on, since otherwise they end up taking up space in the
log that could be used for more useful information.

Tested by opening several files, unlinking them, then
crashing the system, rebooting the system and examining
/var/log/messages.

Addresses the problem described in http://crbug.com/220976

Signed-off-by: Paul Taysom <taysom@chromium.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: fix data offset overflow on 32-bit archs in ext4_inline_data_fiemap()

On 32-bit archs when sector_t is defined as 32-bit the logic computing
data offset in ext4_inline_data_fiemap(). Fix that by properly typing
the shifted value.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4: fix overflows in SEEK_HOLE, SEEK_DATA implementations

ext4_lblk_t is just u32 so multiplying it by blocksize can easily
overflow for files larger than 4 GB. Fix that by properly typing the
block offsets before shifting.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
ext4: use io_end for multiple bios

Change writeback path to create just one io_end structure for the
extent to which we submit IO and share it among bios writing that
extent. This prevents needless splitting and joining of unwritten
extents when they cannot be submitted as a single bio.

Bugs in ENOMEM handling found by Linux File System Verification project
(linuxtesting.org) and fixed by Alexey Khoroshilov
<khoroshilov@ispras.ru>.

CC: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2: use kmem_cache_zalloc for allocating journal head

This commit tries to use kmem_cache_zalloc instead of kmem_cache_alloc/
memset when a new journal head is alloctated.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
jbd2: fix block tag checksum verification brokenness

Al Viro complained of a ton of bogosity with regards to the jbd2 block
tag header checksum.  This one checksum is 16 bits, so cut off the
upper 16 bits and treat it as a 16-bit value and don't mess around
with be32* conversions.  Fortunately metadata checksumming is still
"experimental" and not in a shipping e2fsprogs, so there should be few
users affected by this.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
jbd2: don't create journal_head for temporary journal buffers

When writing metadata to the journal, we create temporary buffer heads
for that task.  We also attach journal heads to these buffer heads but
the only purpose of the journal heads is to keep buffers linked in
transaction's BJ_IO list.  We remove the need for journal heads by
reusing buffer_head's b_assoc_buffers list for that purpose.  Also
since BJ_IO list is just a temporary list for transaction commit, we
use a private list in jbd2_journal_commit_transaction() for that thus
removing BJ_IO list from transaction completely.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2: remove journal_head from descriptor buffers

Similarly as for metadata buffers, also log descriptor buffers don't
really need the journal head. So strip it and remove BJ_LogCtl list.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>