There are several places where GFP_KERNEL allocations happen under a glock,
which will result in hangs if we're under memory pressure and go to re-enter the
fs in order to flush stuff out.  This patch changes the culprits to GFS_NOFS to
keep this problem from happening.  Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

The function gfs2_inode_lookup always returns either a valid pointer or a
value made with ERR_PTR, so its result should be tested with IS_ERR, not
with a test for 0.

The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

//<smpl>
@a@
expression E, E1;
statement S,S1;
position p;
@@

E = gfs2_inode_lookup(...)
... when != E = E1
if@p (E) S else S1

@n@
position a.p;
expression E,E1;
statement S,S1;
@@

E = NULL
... when != E = E1
if@p (E) S else S1

@depends on !n@
expression E;
statement S,S1;
position a.p;
@@

* if@p (E)
  S else S1
//</smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

GFS2 wasn't invalidating its cache before it called into the lock manager
with a request that could potentially drop a lock.  This was leaving a
window where the lock could be actually be held by another node, but the
file's page cache would still appear valid, causing coherency problems.
This patch moves the cache invalidation to before the lock manager call
when dropping a lock. It also adds the option to the lock_dlm lock
manager to not use conversion mode deadlock avoidance, which, on a
conversion from shared to exclusive, could internally drop the lock, and
then reacquire in. GFS2 now asks lock_dlm to not do this.  Instead, GFS2
manually drops the lock and reacquires it.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/recovery.c: In function 'get_log_header':
fs/gfs2/recovery.c:152: warning: 'lh.lh_sequence' may be used uninitialized in this function
fs/gfs2/recovery.c:152: warning: 'lh.lh_flags' may be used uninitialized in this function
fs/gfs2/recovery.c:152: warning: 'lh.lh_tail' may be used uninitialized in this function
fs/gfs2/recovery.c:152: warning: 'lh.lh_blkno' may be used uninitialized in this function
fs/gfs2/recovery.c:152: warning: 'lh.lh_hash' may be used uninitialized in this function

Cc: David Teigland <teigland@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This version of the gfs2_bitfit algorithm includes the latest
suggestions from Steve Whitehouse.  It is typically eight to
ten times faster than the version we're using today.  If there
is a lot of metadata mixed in (lots of small files) the
algorithm is often 15 times faster, and given the right
conditions, I've seen peaks of 20 times faster.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch streamlines the quota checking in the "no quota" case by
making the check inline in the calling function, thus reducing the
number of function calls. Eventually we might be able to remove the
checks from the gfs2_quota_lock() and gfs2_quota_check() functions, but
currently we can't as there are a very few places in the code which need
to call these functions directly still.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>

In an earlier patch "[GFS2] fix file_system_type leak on gfs2meta mount"
we removed the code to grab a ref to the module which was not needed
(since we know that the module cannot be unloaded at that time) so
this patch removes the code to drop that reference.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch combines the 2 patches in bug 434736 to correct the lock
ordering in the unstuffing of the quota inode in gfs2_adjust_quota and
adjusting the number of revokes in gfs2_write_jdata_pagevec
Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

gfs2_alloc_get may fail so we have to check it to prevent
NULL pointer dereference.
Signed-off-by: Cyrill Gorcunov <gorcunov@gamil.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

We need to ensure that sector_t is 64bits for GFS2, so that we need to
depend on LBD as well as LSF.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

a previous commit removed call to
init_special_inode from inode lookuping, this cause problems as:

 # mknod /mnt/gfs2/dev/null c 1 3
 # cat /mnt/gfs2/dev/null
 cat: /mnt/gfs2/dev/null: Invalid argument

without special inode, GFS2 cannot support char device file,
block device file, fifo pipe, and socket file, lose many important
features as a common file system.

this one line patch re add special inode support.
Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

struct inode_operations gfs2_dev_iops is always the same as gfs2_file_iops,
since Jan 2006, when GFS2 merged into mainstream kernel.

So one of them could be removed.
Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

get_gfs2_sb does a get_fs_type without doing a put_filesystem and
thus leaking a file_system_type reference everytime it's called.

Just use gfs2_fs_type directly instead of doing the lookup and thus
fix the problem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

We've supported mapping of extents when no block allocation is required
for some time. This patch extends that to mapping of extents when an
allocation has been requested. In that case we try to allocate as many
blocks as are requested, but we might return fewer in case there is
something preventing us from returning the complete amount (e.g. an
already allocated block is in the way).

Currently the only code path which can actually request multiple data
blocks in a single bmap call is the page_mkwrite path and even then it
only happens if there are multiple blocks per page. What this patch does
do however, is merge the allocation requests for metadata (growing the
metadata tree in either height or depth) with the allocation of the data
blocks in the case that both are needed. This results in lower overheads
even in the single block allocation case.

The one thing which we can't handle here at the moment is unstuffing. I
would like to be able to do that, but the problem which arises is that
in order to unstuff one has to get a locked page from the page cache
which results in locking problems in the (usual) case that the caller is
holding the page lock on the page it wishes to map. So that case will
have to be addressed in future patches.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

We've previously been using a "try lock" in readpage on the basis that
it would prevent deadlocks due to the inverted lock ordering (our normal
lock ordering is glock first and then page lock). Unfortunately tests
have shown that this isn't enough. If the glock has a demote request
queued such that run_queue() in the glock code tries to do a demote when
its called under readpage then it will try and write out all the dirty
pages which requires locking them. This then deadlocks with the page
locked by readpage.

The solution is to always require two calls into readpage. The first
unlocks the page, gets the glock and returns AOP_TRUNCATED_PAGE, the
second does the actual readpage and unlocks the glock & page as
required.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch adds a proper extern declaration for gdlm_ops in
fs/gfs2/locking/dlm/lock_dlm.h
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Every file should include the headers containing the prototypes for
its global functions (in this case for gfs2_set_inode_flags()).
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

replace all:
big_endian_variable = cpu_to_beX(beX_to_cpu(big_endian_variable) +
					expression_in_cpu_byteorder);
with:
	beX_add_cpu(&big_endian_variable, expression_in_cpu_byteorder);
generated with semantic patch
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

As a result of an earlier patch, drop_bh was being called in cases
when it shouldn't have been. Since we never have a gh in the drop
case and we always have a gh in the promote case, we can use that
extra information to tell which case has been seen.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

In the case that we needed to grow the height of the metadata tree
we were looking up the inode buffer and then brelse()ing it despite
the fact that it is needed later in the block map process.

This patch ensures that we look up the inode's buffer once and only
once during the block map process.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

The blocks counter is almost a duplicate of the i_blocks
field in the VFS inode. The only difference is that i_blocks
can be only 32bits long for 32bit arch without large single file
support. Since GFS2 doesn't handle the non-large single file
case (for 32 bit anyway) this adds a new config dependency on
64BIT || LSF. This has always been the case, however we've never
explicitly said so before.

Even if we do add support for the non-LSF case, we will still
not require this field to be duplicated since we will not be
able to access oversized files anyway.

So the net result of all this is that we shave 8 bytes from a gfs2_inode
and get our config deps correct.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This adds a function (currently the only use is during mapping
of already allocated blocks, but watch this space) which iterates
over a number of pointers in a block and returns the extent length.

If the initial pointer is 0 (i.e. unallocated) it will return the
number of unallocated blocks in the extent. If the initial pointer
is allocated, then it returns the number of contiguously allocated
blocks in the extent.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

A dereference was forgotten. This adds it back correctly.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Rather than having to allocate a single block at a time, this patch
allows the block allocator to allocate an extent. Since there is
no difference (so far as the block allocator is concerned) between
data blocks and indirect blocks, it is posible to allocate a single
extent and for the caller to unrevoke just the blocks required
for indirect blocks.

Currently the only bit of GFS2 to make use of this feature is the
build height function. The intention is that gfs2_block_map will
be changed to make use of this feature in future patches.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Thanks to the preceeding patches, the only difference between
these two functions is their name. We can thus merge them
and call the new function gfs2_alloc_block to reflect the
fact that it can allocate either kind of block.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

By adding an extra argument to gfs2_trans_add_unrevoke we can now
specify an extent length of blocks to unrevoke. This means that
we only need to make one pass through the list for each extent
rather than each block. Currently the only extent length which
is used is 1, but that will change in the future.

Also gfs2_trans_add_unrevoke is removed from gfs2_alloc_meta
since its the only difference between this and gfs2_alloc_data
which is left. This will allow a future patch to merge these
two functions into one (i.e. one call to allocate both data
and metadata in a single extent in the future).
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

We don't need to keep track of when we last allocated data
and metadata separately since the only thing thats important
when searching for a free block is whether its free or not,
which is independent from what type of block it is.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

There were three fields being used to keep track of the location
of the most recently allocated block for each inode. These have
been merged into a single field in order to better keep the
data and metadata for an inode close on disk, and also to reduce
the space required for storage.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This is kind of trivial in the greater scheme of things, but
this removes three counters that AFAICT are never used.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch forms a pair with the previous patch which shrunk
di_height. Like that patch di_depth is renamed i_depth and moved
into struct gfs2_inode directly. Also the field goes from 16 bits
to 8 bits since it is also limited to a max value which is rather
small (17 in this case). In addition we also now validate the field
against this maximum value when its read in.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch further reduces GFS2's memory requirements by
eliminating the 64-bit version number fields in lieu of
a couple bits.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

The functions in lm.c were just wrappers which were mostly
only used in one other file. By moving the functions to
the files where they are being used, they can be marked
static and also this will usually result in them being inlined
since they are often only used from one point in the code.

A couple of really trivial functions have been inlined by hand
into the function which called them as it makes the code clearer
to do that.

We also gain from one fewer function call in the glock lock and
unlock paths.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch further reduces the memory needs of GFS2 by
eliminating the gl_req_bh variable from struct gfs2_glock.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

There are a couple of routines which scan bitmaps where we can
mark the bitmaps const, plus a couple of call sites that can
be updated too.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

The reason for doing this is to allow all the block mapping code
to share the same array. As a result we can remove two arguments
from lookup_metapath since they are now returned via the array.

We also add a function to drop all refs to buffer heads when we
are done with the metapath. The build_height function shares the
struct metapath, but currently still frees its own buffers, and
this will change in a future patch.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This is required to enable future changes to the block
mapping code.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch reduces memory by replacing the int variable
gl_waiters2 by a single bit in the gl_flags.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch reduces the memory required by GFS2 by combining
the rd_flags and rg_flags (in core only).
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

This patch moves the gfs2_rgrpd structure to its own slab
memory.  This makes it easier to control and monitor, and
yields less memory fragmentation.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>