Following on from the recent clean up of gfs2_quotad, this patch moves
the processing of "truncate in progress" inodes from the glock workqueue
into gfs2_quotad. This fixes a hang due to the "truncate in progress"
processing requiring glocks in order to complete.

It might seem odd to use gfs2_quotad for this particular item, but
we have to use a pre-existing thread since creating a thread implies
a GFP_KERNEL memory allocation which is not allowed from the glock
workqueue context. Of the existing threads, gfs2_logd and gfs2_recoverd
may deadlock if used for this operation. gfs2_scand and gfs2_glockd are
both scheduled for removal at some (hopefully not too distant) future
point. That leaves only gfs2_quotad whose workload is generally fairly
light and is easily adapted for this extra task.

Also, as a result of this change, it opens the way for a future patch to
make the reading of the inode's information asynchronous with respect to
the glock workqueue, which is another improvement that has been on the list
for some time now.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Although the glock dumps print quite a lot of information about
the glocks themselves, there are more things which can be
usefully added to the dump realting to the objects themselves.

This patch adds a few more fields to the inode and resource
group lines, which should be useful for debugging.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The final field in gfs2_dinode_host was the i_flags field. Thats
renamed to i_diskflags in order to avoid confusion with the existing
inode flags, and moved into the inode proper at a suitable location
to avoid creating a "hole".

At that point struct gfs2_dinode_host is no longer needed and as
promised (quite some time ago!) it can now be removed completely.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch implements a number of cleanups to the core of the
GFS2 glock code. As a result a lot of code is removed. It looks
like a really big change, but actually a large part of this patch
is either removing or moving existing code.

There are some new bits too though, such as the new run_queue()
function which is considerably streamlined. Highlights of this
patch include:

 o Fixes a cluster coherency bug during SH -> EX lock conversions
 o Removes the "glmutex" code in favour of a single bit lock
 o Removes the ->go_xmote_bh() for inodes since it was duplicating
   ->go_lock()
 o We now only use the ->lm_lock() function for both locks and
   unlocks (i.e. unlock is a lock with target mode LM_ST_UNLOCKED)
 o The fast path is considerably shortly, giving performance gains
   especially with lock_nolock
 o The glock_workqueue is now used for all the callbacks from the DLM
   which allows us to simplify the lock_dlm module (see following patch)
 o The way is now open to make further changes such as eliminating the two
   threads (gfs2_glockd and gfs2_scand) in favour of a more efficient
   scheme.

This patch has undergone extensive testing with various test suites
so it should be pretty stable by now.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

This patch fixes a GFS2 filesystem consistency error reported from
function do_strip.  The problem was caused by a timing window
that allowed two vfs inodes to be created in memory that point
to the same file.  The problem is fixed by making the vfs's
iget_test, iget_set mechanism check and set a new bit in the
in-core gfs2_inode structure while the vfs inode spin_lock is held.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven 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: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Previously we were doing (write data, wait for data, write metadata, wait
for metadata). After this patch we so (write metadata, write data, wait for
data, wait for metadata) which should be more efficient.

Also I noticed that the drop_bh and xmote_bh functions were almost
identical. In fact the only difference was a single test, and that
test is such that in the drop_bh case, it would always evaluate to
the correct result. As such we can use the xmote_bh functions in
all the places where we were using the drop_bh function and remove
the drop_bh functions.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The i_cache was designed to keep references to the indirect blocks
used during block mapping so that they didn't have to be looked
up continually. The idea failed because there are too many places
where the i_cache needs to be freed, and this has in the past been
the cause of many bugs.

In addition there was no performance benefit being gained since the
disk blocks in question were cached anyway. So this patch removes
it in order to simplify the code to prepare for other changes which
would otherwise have had to add further support for this feature.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This cleans up the mmap() code path for GFS2 by implementing the
page_mkwrite function for GFS2. We are thus able to use the
generic filemap_fault function for our ->fault() implementation.

This now means that shared writable mappings will be much more
efficiently shared across the cluster if there is a reasonable
proportion of read activity (the greater proportion, the better).

As a side effect, it also reduces the size of the code, removes
special cases from readpage and readpages, and makes the code
path easier to follow.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The following alters gfs2_trans_add_revoke() to take a struct
gfs2_bufdata as an argument. This eliminates the memory allocation which
was previously required by making use of the already existing struct
gfs2_bufdata. It makes some sanity checks to ensure that the
gfs2_bufdata has been removed from all the lists before its recycled as
a revoke structure. This saves one memory allocation and one free per
revoke structure.

Also as a result, and to simplify the locking, since there is no longer
any blocking code in gfs2_trans_add_revoke() we must hold the log lock
whenever this function is called. This reduces the amount of times we
take and unlock the log lock.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This collects together the operations required to remove a gfs2_bufdata
from the ail lists. Its only called from two places to start with, but
expect to see more of this function in future.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When a lot of IO, with some distributed mmap IO, is run on a GFS2 filesystem in
a cluster, it will deadlock. The reason is that do_no_page() will repeatedly
call gfs2_sharewrite_nopage(), because each node keeps giving up the glock
too early, and is forced to call unmap_mapping_range(). This bumps the
mapping->truncate_count sequence count, forcing do_no_page() to retry. This
patch institutes a minimum glock hold time a tenth a second.  This insures
that even in heavy contention cases, the node has enough time to get some
useful work done before it gives up the glock.

A second issue is that when gfs2_glock_dq() is called from within a page fault
to demote a lock, and the associated page needs to be written out, it will
try to acqire a lock on it, but it has already been locked at a higher level.
This patch puts makes gfs2_glock_dq() use the work queue as well, to avoid this
issue. This is the same patch as Steve Whitehouse originally proposed to fix
this issue, execpt that gfs2_glock_dq() now grabs a reference to the glock
before it queues up the work on it.
Signed-off-by: NBenjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes some bugs relating to journaled data files by cleaning
up the gfs2_invalidatepage() and gfs2_releasepage() functions. We now
never block during gfs2_releasepage(), instead we always either release
or refuse to release depending on the status of the buffers.

This fixes Red Hat bugzillas #248969 and #252392.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

Fix for bz #231910
When filemap_fdatawrite() is called on the inode mapping in data=ordered mode,
it will add the glock to the log. In inode_go_sync(), if you do the
gfs2_log_flush() before this, after the filemap_fdatawrite() call, the glock
and its associated data buffers will be on the log again. This means you can
demote a lock from exclusive, without having it flushed from the log. The
attached patch simply moves the gfs2_log_flush up to after the
filemap_fdatawrite() call.

Originally, I tried moving the gfs2_log_flush to after gfs2_meta_sync(), but
that caused me to trip the following assert.

GFS2: fsid=cypher-36:test.0: fatal: assertion "!buffer_busy(bh)" failed
GFS2: fsid=cypher-36:test.0:   function = gfs2_ail_empty_gl, file = fs/gfs2/glops.c, line = 61

It appears that gfs2_log_flush() puts some of the glocks buffers in the busy
state and the filemap_fdatawrite() call is necessary to flush them. This makes
me worry slightly that a related problem could happen because of moving the
gfs2_log_flush() after the initial filemap_fdatawrite(), but I assume that
gfs2_ail_empty_gl() would catch that case as well.
Signed-off-by: NBenjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Cleanup: setting an outstanding error on a mapping was open coded too many
times.  Factor it out in mapping_set_error().
Signed-off-by: NGuillaume Chazarain <guichaz@yahoo.fr>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following removes an incorrect assertion from the GFS2 glops code. This
fixes Red Hat bz 229873. Thanks to Abhijith Das for testing the patch
and confirming the fix.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>

The below patch fixes a problem where we were not flushing rgrps
correctly. It only occurred in the specific case that a callback was
received for an rgrp which was dirty and when a journal log flush had
not already resulted in the rgrp being flushed anyway. This fixes Red
Hat bz 230143,
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: NTim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch doesn't make any changes to the ordering of the various
operations related to glocking, but it does tidy up the calls to the
glops.c functions to make the structure more obvious.

The two functions: gfs2_glock_xmote_th() and gfs2_glock_drop_th() can be
made static within glock.c since they are called by every set of glock
operations. The xmote_th and drop_th glock operations are then made
conditional upon those two routines existing and called from the
previously mentioned functions in glock.c respectively.

Also it can be seen that the go_sync operation isn't needed since it can
easily be replaced by calls to xmote_bh and drop_bh respectively. This
results in no longer (confusingly) calling back into routines in glock.c
from glops.c and also reducing the glock operations by one member.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Here is a patch for GFS2 to remove the local exclusive flag. In
the places it was used, mutex's are always held earlier in the
call path, so it appears redundant in the LM_ST_SHARED case.

Also, the GFS2 holders were setting local exclusive in any case where
the requested lock was LM_ST_EXCLUSIVE. So the other places in the glock
code where the flag was tested have been replaced with tests for the
lock state being LM_ST_EXCLUSIVE in order to ensure the logic is the
same as before (i.e. LM_ST_EXCLUSIVE is always locally exclusive as well
as globally exclusive).
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The "greedy" code was an attempt to retain glocks for a minimum length
of time when they relate to mmap()ed files. The current implementation
of this feature is not, however, ideal in that it required allocating
memory in order to do this and its overly complicated.

It also misses the mark by ignoring the other I/O operations which are
just as likely to suffer from the same problem. So the plan is to remove
this now and then add the functionality back as part of the glock state
machine at a later date (and thus take into account all the possible
users of this feature)
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This fixes a bug which resulted in poor performance due to flushing
the journal too often. The code path in question was via the inode_go_sync()
function in glops.c. The solution is not to flush the journal immediately
when inodes are ejected from memory, but batch up the work for glockd to
deal with later on. This means that glocks may now live on beyond the end of
the lifetime of their inodes (but not very much longer in the normal case).

Also fixed in this patch is a bug (which was hidden by the bug mentioned above) in
calculation of the number of free journal blocks.

The gfs2_logd process has been altered to be more responsive to the journal
filling up. We now wake it up when the number of uncommitted journal blocks
has reached the threshold level rather than trying to flush directly at the
end of each transaction. This again means doing fewer, but larger, log
flushes in general.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The go_sync callback took two flags, but one of them was set on every
call, so this patch removes once of the flags and makes the previously
conditional operations (on this flag), unconditional.

The go_inval callback took three flags, each of which was set on every
call to it. This patch removes the flags and makes the operations
unconditional, which makes the logic rather more obvious.

Two now unused flags are also removed from incore.h.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This function wasn't really doing the right thing. There was no need
to update the inode size at this point and the updating of the
i_blocks field has now been moved to the places where di_blocks is
updated. A result of this patch and some those preceeding it is that
unlocking a glock is now a much more efficient process, since there
is no longer any requirement to copy data from the gfs2 inode into
the vfs inode at this point.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This shrinks the size of the gfs2_inode by 8 bytes by
replacing the version counter with a one bit valid/invalid
flag.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This removes the duplicate di_mode field in favour of using the
inode->i_mode field. This saves 4 bytes.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This moves the logging code from meta_io.c into log.c and glops.c. As a
result the routines can now be static and all the logging code is together
in log.c, leaving meta_io.c with just metadata i/o code in it.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Fix a bug in the directory reading code, where we might have dereferenced
a NULL pointer in case of OOM. Updated the directory code to use the new
& improved version of gfs2_meta_ra() which now returns the first block
that was being read. Previously it was releasing it requiring following
code to grab the block again at each point it was called.

Also turned off readahead on directory lookups since we are reading a
hash table, and therefore reading the entries in order is very
unlikely. Readahead is still used for all other calls to the
directory reading function (e.g. when growing the hash table).

Removed the DIO_START constant. Everywhere this was used, it was
used to unconditionally start i/o aside from a couple of places, so
I've removed it and made the couple of exceptions to this rule into
separate functions.

Also hunted through the other DIO flags and removed them as arguments
from functions which were always called with the same combination of
arguments.

Updated gfs2_meta_indirect_buffer to be a bit more efficient and
hopefully also be a bit easier to read.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

lm_interface.h has a few out of the tree clients such as GFS1
and userland tools.

Right now, these clients keeps a copy of the file in their build tree
that can go out of sync.

Move lm_interface.h to include/linux, export it to userland and
clean up fs/gfs2 to use the new location.
Signed-off-by: NFabio M. Di Nitto <fabbione@ubuntu.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The callback for iopen locks is unused, so this removes
it.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

As per Jan Engelhardt's request, I've added a ',' to the end of
each of the multi-line structures which didn't already have
one (most already did).

Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

As per Jan Engelhardt's third set of comments, this make various
code style changes and moves the structures from format.h into
super.c, which was the only place that format.h was actually used.

Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

As per comments from Jan Engelhardt <jengelh@linux01.gwdg.de> this
updates the copyright message to say "version" in full rather than
"v.2". Also incore.h has been updated to remove forward structure
declarations which are not required.

The gfs2_quota_lvb structure has now had endianess annotations added
to it. Also quota.c has been updated so that we now store the
lvb data locally in endian independant format to avoid needing
a structure in host endianess too. As a result the endianess
conversions are done as required at various points and thus the
conversion routines in lvb.[ch] are no longer required. I've
moved the one remaining constant in lvb.h thats used into lm.h
and removed the unused lvb.[ch].

I have not changed the HIF_ constants. That is left to a later patch
which I hope will unify the gh_flags and gh_iflags fields of the
struct gfs2_holder.

Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Remove the unused sync feature from glocks. This is currently done by
calling the required functions to sync pages/blocks directly so this
code isn't needed.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

For all the usual reasons of enforcing correctness and potentially
reducing code size, this patch makes the glock operations const.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This means that we don't need to create a special inode just to contain
a struct address_space in order to read a single disk block. Instead
we read the disk block directly. Its slightly faster, and uses slightly
less memory, but the real reason for doing this is that it removes a
special case from the glock code.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The remaining routines in page.c were all only used in one other
file, so they are now moved into the files where they are referenced
and made static. Thus page.[ch] are no longer required.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

A few of my printks slipped through last time. Also fix a couple of
minor bugs.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes the way we have been dealing with unlinked,
but still open files. It removes all limits (other than memory
for inodes, as per every other filesystem) on numbers of these
which we can support on GFS2. It also means that (like other
fs) its the responsibility of the last process to close the file
to deallocate the storage, rather than the person who did the
unlinking. Note that with GFS2, those two events might take place
on different nodes.

Also there are a number of other changes:

 o We use the Linux inode subsystem as it was intended to be
used, wrt allocating GFS2 inodes
 o The Linux inode cache is now the point which we use for
local enforcement of only holding one copy of the inode in
core at once (previous to this we used the glock layer).
 o We no longer use the unlinked "special" file. We just ignore it
completely. This makes unlinking more efficient.
 o We now use the 4th block allocation state. The previously unused
state is used to track unlinked but still open inodes.
 o gfs2_inoded is no longer needed
 o Several fields are now no longer needed (and removed) from the in
core struct gfs2_inode
 o Several fields are no longer needed (and removed) from the in core
superblock

There are a number of future possible optimisations and clean ups
which have been made possible by this patch.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>