mm: slub: Default slub_max_order to 0

To avoid locking and per-cpu overhead, SLUB optimisically uses
high-order allocations up to order-3 by default and falls back to
lower allocations if they fail. While care is taken that the caller
and kswapd take no unusual steps in response to this, there are
further consequences like shrinkers who have to free more objects to
release any memory. There is anecdotal evidence that significant time
is being spent looping in shrinkers with insufficient progress being
made (https://lkml.org/lkml/2011/4/28/361) and keeping kswapd awake.

SLUB is now the default allocator and some bug reports have been
pinned down to SLUB using high orders during operations like
copying large amounts of data. SLUBs use of high-orders benefits
applications that are sized to memory appropriately but this does not
necessarily apply to large file servers or desktops.  This patch
causes SLUB to use order-0 pages like SLAB does by default.
There is further evidence that this keeps kswapd's usage lower
(https://lkml.org/lkml/2011/5/10/383).

Signed-off-by: Mel Gorman <mgorman@suse.de>
mm: vmscan: If kswapd has been running too long, allow it to sleep

Under constant allocation pressure, kswapd can be in the situation where
sleeping_prematurely() will always return true even if kswapd has been
running a long time. Check if kswapd needs to be scheduled.

Signed-off-by: Mel Gorman <mgorman@suse.de>
msm: hotplug: Add options for number of min/max/boost cpus
ext4: create a new BH_Verified flag to avoid unnecessary metadata validation

Create a new BH_Verified flag to indicate that we've verified all the
data in a buffer_head for correctness.  This allows us to bypass
expensive verification steps when they are not necessary without
missing them when they are.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: change on-disk layout to support extended metadata checksumming

Define flags and change structure definitions to allow checksumming of
ext4 metadata.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: record the checksum algorithm in use in the superblock

Record the type of checksum algorithm we're using for metadata in the
superblock, in case we ever want/need to change the algorithm.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: load the crc32c driver if necessary

Obtain a reference to the cryptoapi and crc32c if we mount a
filesystem with metadata checksumming enabled.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: remove unnecessary check in add_dirent_to_buf()

None of this function callers ever pass in a NULL inode pointer, so
this check is unnecessary, and the else clause is dead code.  (This
change should make the code coverage people a little happier.  :-)

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
vfs: Rename end_writeback() to clear_inode()

After we moved inode_sync_wait() from end_writeback() it doesn't make sense
to call the function end_writeback() anymore. Rename it to clear_inode()
which well says what the function really does - set I_CLEAR flag.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
ext4: Remove i_mutex use from ext4_quota_write()

We don't need i_mutex in ext4_quota_write() because writes to quota file
are serialized by dqio_mutex anyway. Changes to quota files outside of quota
code are forbidded and enforced by NOATIME and IMMUTABLE bits.

Signed-off-by: Jan Kara <jack@suse.cz>
ext4: remove needs_recovery in ext4_mb_init()

needs_recovery in ext4_mb_init() is not used, remove it.

Signed-off-by: Akira Fujita <a-fujita@rs.jp.ne.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: remove redundundant "(char *) bh->b_data" casts

The b_data field of the buffer_head is already a char *, so there's no
point casting it to a char *.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: return ENOMEM when mounts fail due to lack of memory

This is a port of the ext3 commit: 4569cd1b0d9

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: cleanup in ext4_discard_allocated_blocks()

remove 'len' variable in ext4_discard_allocated_blocks() because it is
useless.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: fix format flag in ext4_ext_binsearch_idx()

fix ext_debug format flag in ext4_ext_binsearch_idx().

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: use consistent ssize_t type in ext4_file_write()

The generic_file_aio_write() function returns ssize_t, and
ext4_file_write() returns a ssize_t, so use a ssize_t to collect the
return value from generic_file_aio_write().  It shouldn't matter since
the VFS read/write paths shouldn't allow a read greater than MAX_INT,
but there was previously a bug in the AIO code paths, and it's best if
we use a consistent type so that the return value from
generic_file_aio_write() can't get truncated.

Reported-by: Jouni Siren <jouni.siren@iki.fi>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: add debugging trigger for ext4_error()

Make it easy to test whether or not the error handling subsystem in
ext4 is working correctly.  This allows us to simulate an ext4_error()
by echoing a string to /sys/fs/ext4/<dev>/trigger_fs_error.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ksumrall@google.com
ext4: let getattr report the right blocks in delalloc+bigalloc

In delayed allocation, i_reserved_data_blocks now indicates
clusters, not blocks. So report it in the right number.

This can be easily exposed by the following command:
echo foo > blah; du -hc blah; sync; du -hc blah

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4: don't trash state flags in EXT4_IOC_SETFLAGS

In commit 353eb83c we removed i_state_flags with 64-bit longs, But
when handling the EXT4_IOC_SETFLAGS ioctl, we replace i_flags
directly, which trashes the state flags which are stored in the high
32-bits of i_flags on 64-bit platforms.  So use the the
ext4_{set,clear}_inode_flags() functions which use atomic bit
manipulation functions instead.

Reported-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

Conflicts:
	fs/ext4/ioctl.c
ext4: hole-punch use truncate_pagecache_range

When truncating a file, we unmap pages from userspace first, as that's
usually more efficient than relying, page by page, on the fallback in
truncate_inode_page() - particularly if the file is mapped many times.

Do the same when punching a hole: 3.4 added truncate_pagecache_range()
to do the unmap and trunc, so use it in ext4_ext_punch_hole(), instead
of calling truncate_inode_pages_range() directly.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>