Here is an update of Bob's original rbtree patch which, in addition, also
resolves the rather strange ref counting that was being done relating to
the bitmap blocks.

Originally we had a dual system for journaling resource groups. The metadata
blocks were journaled and also the rgrp itself was added to a list. The reason
for adding the rgrp to the list in the journal was so that the "repolish
clones" code could be run to update the free space, and potentially send any
discard requests when the log was flushed. This was done by comparing the
"cloned" bitmap with what had been written back on disk during the transaction
commit.

Due to this, there was a requirement to hang on to the rgrps' bitmap buffers
until the journal had been flushed. For that reason, there was a rather
complicated set up in the ->go_lock ->go_unlock functions for rgrps involving
both a mutex and a spinlock (the ->sd_rindex_spin) to maintain a reference
count on the buffers.

However, the journal maintains a reference count on the buffers anyway, since
they are being journaled as metadata buffers. So by moving the code which deals
with the post-journal accounting for bitmap blocks to the metadata journaling
code, we can entirely dispense with the rather strange buffer ref counting
scheme and also the requirement to journal the rgrps.

The net result of all this is that the ->sd_rindex_spin is left to do exactly
one job, and that is to look after the rbtree or rgrps.

This patch is designed to be a stepping stone towards using RCU for the rbtree
of resource groups, however the reduction in the number of uses of the
->sd_rindex_spin is likely to have benefits for multi-threaded workloads,
anyway.

The patch retains ->go_lock and ->go_unlock for rgrps, however these maybe also
be removed in future in favour of calling the functions directly where required
in the code. That will allow locking of resource groups without needing to
actually read them in - something that could be useful in speeding up statfs.

In the mean time though it is valid to dereference ->bi_bh only when the rgrp
is locked. This is basically the same rule as before, modulo the references not
being valid until the following journal flush.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Cc: Benjamin Marzinski <bmarzins@redhat.com>

__gfs2_free_data and __gfs2_free_meta are almost identical, and
can be trivially combined.

[This is as per Eric's original patch minus gfs2_free_data() which had
 no callers left and plus the conversion of the bmap.c calls to these
 functions. All in all, a nice clean up]
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The deallocation code for directories in GFS2 is largely divided into
two parts. The first part deallocates any directory leaf blocks and
marks the directory as being a regular file when that is complete. The
second stage was identical to deallocating regular files.

Regular files have their data blocks in a different
address space to directories, and thus what would have been normal data
blocks in a regular file (the hash table in a GFS2 directory) were
deallocated correctly. However, a reference to these blocks was left in the
journal (assuming of course that some previous activity had resulted in
those blocks being in the journal or ail list).

This patch uses the i_depth as a test of whether the inode is an
exhash directory (we cannot test the inode type as that has already
been changed to a regular file at this stage in deallocation)

The original issue was reported by Chris Hertel as an issue he encountered
running bonnie++
Reported-by: NChristopher R. Hertel <crh@samba.org>
Cc: Abhijith Das <adas@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Rather than allowing the glocks to be scheduled for possible
reclaim as soon as they have exited the journal, this patch
delays their entry to the list until the glocks in question
are no longer in use.

This means that we will rely on the vm for writeback of all
dirty data and metadata from now on. When glocks are added
to the lru list they should be freeable much faster since all
the I/O required to free them should have already been completed.

This should lead to much better I/O patterns under low memory
conditions.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

On rare occasions we encounter gfs2 problems where an
invalid bitmap state transition is attempted.  For example,
trying to "unlink" a free block.  In these cases, there
is really no useful information logged to debug the problem.
This patch adds more debug details that should allow us to
more closely examine the problem and possibly solve it.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes a deadlock in GFS2 where two processes are trying
to reclaim an unlinked dinode:
One holds the inode glock and calls gfs2_lookup_by_inum trying to look
up the inode, which it can't, due to I_FREEING.  The other has set
I_FREEING from vfs and is at the beginning of gfs2_delete_inode
waiting for the glock, which is held by the first.  The solution is to
add a new non_block parameter to the gfs2_iget function that causes it
to return -ENOENT if the inode is being freed.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch is a performance improvement to GFS2's dealloc code.
Rather than update the quota file and statfs file for every
single block that's stripped off in unlink function do_strip,
this patch keeps track and updates them once for every layer
that's stripped.  This is done entirely inside the existing
transaction, so there should be no risk of corruption.
The other functions that deallocate blocks will be unaffected
because they are using wrapper functions that do the same
thing that they do today.

I tested this code on my roth cluster by creating 200
files in a directory, each of which is 100MB, then on
four nodes, I simultaneously deleted the files, thus competing
for GFS2 resources (but different files).  The commands
I used were:

[root@roth-01]# time for i in `seq 1 4 200` ; do rm /mnt/gfs2/bigdir/gfs2.$i; done
[root@roth-02]# time for i in `seq 2 4 200` ; do rm /mnt/gfs2/bigdir/gfs2.$i; done
[root@roth-03]# time for i in `seq 3 4 200` ; do rm /mnt/gfs2/bigdir/gfs2.$i; done
[root@roth-05]# time for i in `seq 4 4 200` ; do rm /mnt/gfs2/bigdir/gfs2.$i; done

The performance increase was significant:

             roth-01     roth-02     roth-03     roth-05
             ---------   ---------   ---------   ---------
old: real    0m34.027    0m25.021s   0m23.906s   0m35.646s
new: real    0m22.379s   0m24.362s   0m24.133s   0m18.562s

Total time spent deleting:
old: 118.6s
new:  89.4

For this particular case, this showed a 25% performance increase for
GFS2 unlinks.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When you do gfs2_grow it failed to take the very last
rgrp into account when adding up the new free space due
to an off-by-one error.  It was not reading the last
rgrp from the rindex because of a check for "<=" that
should have been "<".  Therefore, fsck.gfs2 was finding
(and fixing) an error with the system statfs file.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>

When you truncate the rindex file, you need to avoid calling gfs2_rindex_hold,
since you already hold it.  However, if you haven't already read in the
resource groups, you need to do that.
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When GFS2 grew the filesystem, it was never rereading the rindex file during
the grow. This is necessary for large grows when the filesystem is almost full,
and GFS2 needs to use some of the space allocated earlier in the grow to
complete it.  Now, if GFS2 fails to reserve the necessary space and the rindex
file is not uptodate, it rereads it.  Also, the only difference between
gfs2_ri_update() and gfs2_ri_update_special() was that gfs2_ri_update_special()
didn't clear out the existing resource groups, since you knew that it was only
called when there were no resource groups.  Attempting to clear out the
resource groups when there are none takes almost no time, and rarely happens,
so I simply removed gfs2_ri_update_special().
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This area of the code has always been a bit delicate due to the
subtleties of lock ordering. The problem is that for "normal"
alloc/dealloc, we always grab the inode locks first and the rgrp lock
later.

In order to ensure no races in looking up the unlinked, but still
allocated inodes, we need to hold the rgrp lock when we do the lookup,
which means that we can't take the inode glock.

The solution is to borrow the technique already used by NFS to solve
what is essentially the same problem (given an inode number, look up
the inode carefully, checking that it really is in the expected
state).

We cannot do that directly from the allocation code (lock ordering
again) so we give the job to the pre-existing delete workqueue and
carry on with the allocation as normal.

If we find there is no space, we do a journal flush (required anyway
if space from a deallocation is to be released) which should block
against the pending deallocations, so we should always get the space
back.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes a GFS2 problem whereby the first rename after a
mount can result in a file system consistency error being flagged
improperly and cause the file system to withdraw.  The problem is
that the rename code tries to run the rgrp list with function
gfs2_blk2rgrpd before the rgrp list is guaranteed to be read in
from disk.  The patch makes the rename function hold the rindex
glock (as the gfs2_unlink code does today) which reads in the rgrp
list if need be.  There were a total of three places in the rename
code that improperly referenced the rgrp list without the rindex
glock and this patch fixes all three.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch adds support for fallocate to gfs2.  Since the gfs2 does not support
uninitialized data blocks, it must write out zeros to all the blocks.  However,
since it does not need to lock any pages to read from, gfs2 can write out the
zero blocks much more efficiently.  On a moderately full filesystem, fallocate
works around 5 times faster on average.  The fallocate call also allows gfs2 to
add blocks to the file without changing the filesize, which will make it
possible for gfs2 to preallocate space for the rindex file, so that gfs2 can
grow a completely full filesystem.
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This adds a check to ensure that if we reach the block allocator
that we don't try and proceed if there is no alloc structure
hanging off the inode. This should only happen if there is a bug
in GFS2. The error return code is distinctive in order that it
will be easily spotted.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

With the update of the truncate code, ip->i_disksize and
inode->i_size are merely copies of each other. This means
we can remove ip->i_disksize and use inode->i_size exclusively
reducing the size of a GFS2 inode by 8 bytes.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

All the blkdev_issue_* helpers can only sanely be used for synchronous
caller.  To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead.  So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout.  For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Switch to the WRITE_FLUSH_FUA flag for log writes, remove the EOPNOTSUPP
detection for barriers and stop setting the barrier flag for discards.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>
Acked-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The previous patch I wrote for reclaiming unlinked dinodes
had some shortcomings and did not prevent all hangs.
This version is much cleaner and more logical, and has
passed very difficult testing.  Sorry for the churn.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch changes the lock ordering when gfs2 reclaims
unlinked dinodes, thereby avoiding a livelock.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The patch just convert all blkdev_issue_xxx function to common
set of flags. Wait/allocation semantics preserved.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch fixes a couple gfs2 problems with the reclaiming of
unlinked dinodes.  First, there were a couple of livelocks where
everything would come to a halt waiting for a glock that was
seemingly held by a process that no longer existed.  In fact, the
process did exist, it just had the wrong pid number in the holder
information.  Second, there was a lock ordering problem between
inode locking and glock locking.  Third, glock/inode contention
could sometimes cause inodes to be improperly marked invalid by
iget_failed.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>

This is called under a glock, so its a good plan to use GFP_NOFS
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The do_div() call needs to remain.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

ince gfs2 writes the rindex file a block at a time, and releases the
exclusive lock after each block, it is possible that another process
will grab the lock in the middle of the write.  Since rindex entries are
not an even divisor of blocks, that other process may see partial
entries.  On grows, this is fine.  The process can simply ignore the the
partial entires. Previously, the code withdrew when it saw partial
entries. Now it simply ignores them.
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

In some cases we already have the rindex lock when
we enter this function.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Signed-off-by: NAnand Gadiyar <gadiyar@ti.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Reported-by: NDaniel Walker <dwalker@fifo99.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

blk_ioctl_discard duplicates large amounts of code from blkdev_issue_discard,
the only difference between the two is that blkdev_issue_discard needs to
send a barrier discard request and blk_ioctl_discard a non-barrier one,
and blk_ioctl_discard needs to wait on the request.  To facilitates this
add a flags argument to blkdev_issue_discard to control both aspects of the
behaviour.  This will be very useful later on for using the waiting
funcitonality for other callers.

Based on an earlier patch from Matthew Wilcox <matthew@wil.cx>.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

There is a potential race in the inode deallocation code if two
nodes try to deallocate the same inode at the same time. Most of
the issue is solved by the iopen locking. There is still a small
window which is not covered by the iopen lock. This patches fixes
that and also makes the deallocation code more robust in the face of
any errors in the rgrp bitmaps, or erroneous iopen callbacks from
other nodes.

This does introduce one extra disk read, but that is generally not
an issue since its the same block that must be written to later
in the deallocation process. The total disk accesses therefore stay
the same,
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The inum structure used throughout GFS2 has two fields. One
no_addr is the disk block number of the inode in question and
is used everywhere as the inode number. The other, no_formal_ino,
is used only as the generation number for NFS.

Historically the no_formal_ino field was set using a complicated
system of one global and one per-node file containing inode numbers
in order to ensure that each no_formal_ino was unique. Also this
code made no provision for what would happen when eventually the
(64 bit) numbers ran out. Now I know that is pretty unlikely to
happen given the large space of numbers, but it is possible
nevertheless.

The only guarantee required for no_formal_ino is that, for any
single inode, the same number doesn't get reused too quickly.

We already have a generation number which is kept in the inode
and initialised from a counter in the resource group (almost
no overhead, since we have to touch the resource group anyway
in order to allocate an inode in the first place). Aside from
ensuring that we never use the value 0 in the no_formal_ino
field, we can use that counter directly.

As a result of that change, we lose about 200 lines of code and
also gain about 10 creates/sec on the postmark benchmark (on
my test machine).
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

One fewer assert, one more place we can recover gracefully
if there is an error.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

A little while back, block allocation was given some improved
error handling which meant that -EIO was returned in the case
of there being a problem in the resource group data. In addition
a message is printed explaning what went wrong and how to fix it.
This extends that error handling so that it also covers inode
allocation too.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Since both linked and unlinked inodes are counted by rgd->rd_dinodes, It
makes no sense to count them with the used data blocks (first check that
I changed), it makes sense to count them with the linked inodes (second
check), and it makes no sense to care if there are more unlinked inodes
than linked ones. This fixes these errors.
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When searching for unlinked, but still allocated inodes during block
allocation, avoid the block relating to the inode that is doing the
allocation. This fixes a hang caused when an unlinked, but still
open, inode tries to allocate some more blocks and lands up
finding itself during the search for deallocatable inodes.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been chosen because
they allow inspection of the major internal functions of GFS2
and they are also generic enough that they are unlikely to need
any major changes as the filesystem evolves.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case.  The
sector size will be 4KB but the logical block size will remain
512-bytes.  Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch renames the ops_*.c files which have no counterpart
without the ops_ prefix in order to shorten the name and make
it more readable. In addition, ops_address.h (which was very
small) is moved into inode.h and inode.h is cleaned up by
adding extern where required.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch increases the frequency with which gfs2 looks
for unlinked, but still allocated inodes. Its the equivalent
operation to ext3's orphan list, but done with bitmaps in
the resource groups.

This also fixes a bug where a field in the rgrp was too small.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

During block allocation, it is useful to know if sections of disk
are full on a finer grained basis than a single resource group.
This can make a performance difference when resource groups have
larger numbers of bitmap blocks, since we no longer have to search
them all block by block in each individual bitmap.

The full flag is set on a per-bitmap basis when it has been
searched and found to have no free space. It is then skipped in
subsequent searches until the flag is reset. The resetting
occurs if we have to drop the glock on the resource group for any
reason, or if we deallocate some blocks within that resource
group and thus free up some space.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch improves the error handling in the case where we
discover that the summary information in the resource group
doesn't match the bitmap information while in the process of
allocating blocks. Originally this resulted in a kernel bug,
but this patch changes that so that we return -EIO and print
some messages explaining what went wrong, and how to fix it.

We also remember locally not to try and allocate from the
same rgrp again, so that a subsequent allocation in a
different rgrp should succeed.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>