xfs: fix potential infinite loop in xfs_iomap_prealloc_size()

If freesp == 0, we could end up in an infinite loop while squashing
the preallocation. Break the loop when we've killed the prealloc
entirely.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: increase prealloc size to double that of the previous extent

The updated speculative preallocation algorithm for handling sparse
files can becomes less effective in situations with a high number of
concurrent, sequential writers. The number of writers and amount of
available RAM affect the writeback bandwidth slicing algorithm,
which in turn affects the block allocation pattern of XFS. For
example, running 32 sequential writers on a system with 32GB RAM,
preallocs become fixed at a value of around 128MB (instead of
steadily increasing to the 8GB maximum as sequential writes
proceed).

Update the speculative prealloc heuristic to base the size of the
next prealloc on double the size of the preceding extent. This
preserves the original aggressive speculative preallocation
behavior and continues to accomodate sparse files at a slight cost
of increasing the size of preallocated data regions following holes
of sparse files.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: fix xfs_iomap_eof_prealloc_initial_size type

Fix the return type of xfs_iomap_eof_prealloc_initial_size() to
xfs_fsblock_t to reflect the fact that the return value may be an
unsigned 64 bits if XFS_BIG_BLKNOS is defined.

Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: don't verify buffers after IO errors

When we read a buffer, we might get an error from the underlying
block device and not the real data. Hence if we get an IO error, we
shouldn't run the verifier but instead just pass the IO error
straight through.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: rename random32() to prandom_u32()

Use more preferable function name which implies using a pseudo-random
number generator.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: <bpm@sgi.com>
Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Cc: xfs@oss.sgi.com
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: rearrange some code in xfs_bmap for better locality

xfs_bmap.c is a big file, and some of the related code is spread all
throughout the file requiring function prototypes for static
function and jumping all through the file to follow a single call
path. Rearrange the code so that:

	a) related functionality is grouped together; and
	b) functions are grouped in call dependency order

While the diffstat is large, there are no code changes in the patch;
it is just moving the functionality around and removing the function
prototypes at the top of the file. The resulting layout of the code
is as follows (top of file to bottom):

	- miscellaneous helper functions
	- extent tree block counting routines
	- debug/sanity checking code
	- bmap free list manipulation functions
	- inode fork format manipulation functions
	- internal/external extent tree seach functions
	- extent tree manipulation functions used during allocation
	- functions used during extent read/allocate/removal
	  operations (i.e. xfs_bmapi_write, xfs_bmapi_read,
	  xfs_bunmapi and xfs_getbmap)

This means that following logic paths through the bmapi code is much
simpler - most of the code relevant to a specific operation is now
clustered together rather than spread all over the file....

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: Remove obsoleted m_inode_shrink from xfs_mount structure

Looks the old m_inode_shrink is obsoleted as we perform inodes reclaim per AG via
m_reclaim_workqueue, this patch remove it from the xfs_mount structure if so.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: ensure we capture IO errors correctly

Failed buffer readahead can leave the buffer in the cache marked
with an error. Most callers that then issue a subsequent read on the
buffer do not zero the b_error field out, and so we may incorectly
detect an error during IO completion due to the stale error value
left on the buffer.

Avoid this problem by zeroing the error before IO submission. This
ensures that the only IO errors that are detected those captured
from are those captured from bio submission or completion.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: take inode version into account in XFS_LITINO

Add a version argument to XFS_LITINO so that it can return different values
depending on the inode version.  This is required for the upcoming v3 inodes
with a larger fixed layout dinode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: reorganize xfs_iomap_prealloc_size to remove indentation

The majority of xfs_iomap_prealloc_size() executes within the
check for lack of default I/O size. Reverse the logic to remove the
extra indentation.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: push rounddown_pow_of_two() to after prealloc throttle

The round down occurs towards the beginning of the function. Push
it down after throttling has occurred. This is to support adding
further transformations to 'alloc_blocks' that might not preserve
power-of-two alignment (and thus could lead to rounding down
multiple times).

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: pass xfs_dquot to xfs_qm_adjust_dqlimits() instead of xfs_disk_dquot_t

Modify xfs_qm_adjust_dqlimits() to take the xfs_dquot as a
parameter instead of just the xfs_disk_dquot_t so we can update
in-memory fields if necessary.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: xfs_dquot prealloc throttling watermarks and low free space

Enable tracking of high and low watermarks for preallocation
throttling of files under quota restrictions. These values are
calculated when the quota limit is read from disk or modified and
cached for later use by the throttling algorithm.

The high watermark specifies when preallocation is disabled, the
low watermark specifies when throttling is enabled and the low free
space data structure contains precalculated low free space limits
to serve as input to determine the level of throttling required.

Note that the low free space data structure is based on the
existing global low free space data structure with the exception of
using three stages (5%, 3% and 1%) rather than five to reduce the
impact of xfs_dquot memory overhead.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: add quota-driven speculative preallocation throttling

Introduce the need_throttle() and calc_throttle() functions to
independently check whether throttling is required for a particular
dquot and if so, calculate the associated throttling metrics based
on the state of the quota. We use the same general algorithm to
calculate the throttle shift as for global free space with the
exception of using three stages rather than five.

Update xfs_iomap_prealloc_size() to use the smallest available
prealloc size based on each of the constraints and apply the
maximum shift to obtain the throttled preallocation size.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: xfs_iomap_prealloc_size() tracepoint

Add a tracepoint to provide some feedback on preallocation size
calculation.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage()

When a dirty page is truncated from a file but reclaim gets to it before
truncate_inode_pages(), we hit WARN_ON(delalloc) in
xfs_vm_releasepage(). This is because reclaim tries to write the page,
xfs_vm_writepage() just bails out (leaving page clean) and thus reclaim
thinks it can continue and calls xfs_vm_releasepage() on page with dirty
buffers.

Fix the issue by redirtying the page in xfs_vm_writepage(). This makes
reclaim stop reclaiming the page and also logically it keeps page in a
more consistent state where page with dirty buffers has PageDirty set.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
i2c: core: Pick i2c bus number from dt alias if present

This allows you to get the equivalent functionality of
i2c_add_numbered_adapter() with all data in the device tree and no
special case code in your driver.  This is a common device tree
technique.

For quick reference, the FDT syntax for using an alias to provide an
ID looks like:
  aliases {
    i2c0 = &i2c_0;
    i2c1 = &i2c_1;
  };

Signed-off-by: Doug Anderson <dianders@chromium.org>
[wsa: removed one check from static function. We know our callers]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: Add bus recovery infrastructure

Add i2c bus recovery infrastructure to i2c adapters as specified in the i2c
protocol Rev. 03 section 3.1.16 titled "Bus clear".

http://www.nxp.com/documents/user_manual/UM10204.pdf

Sometimes during operation i2c bus hangs and we need to give dummy clocks to
slave device to start the transfer again. Now we may have capability in the bus
controller to generate these clocks or platform may have gpio pins which can be
toggled to generate dummy clocks. This patch supports both.

This patch also adds in generic bus recovery routines gpio or scl line based
which can be used by bus controller. In addition controller driver may provide
its own version of the bus recovery routine.

This doesn't support multi-master recovery for now.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[wsa: changed gpio type to int and minor reformatting]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: pxa: Use i2c-core to get bus number now

The commit: "i2c-core: dt: Pick i2c bus number from i2c alias if
present" adds support for automatically picking the bus number based
on the alias ID.  Remove the now unnecessary code from i2c-pxa that
did the same thing.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: tegra: assume CONFIG_OF, remove platform data

Tegra only supports, and always enables, device tree. Remove all ifdefs
and runtime checks for DT support from the driver. Platform data is
therefore no longer required. Delete the header that defines it.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>