The issue scenario is as following:

When fallocating a very large disk space for a small file,
__ocfs2_extend_allocation attempts to get a very large transaction.  For
some journal sizes, there may be not enough room for this transaction,
and the fallocate will fail.

The patch below extends & restarts the transaction as necessary while
allocating space, and should work with even the smallest journal.  This
patch refers ext4 resize.

Test:
# mkfs.ocfs2 -b 4K -C 32K -T datafiles /dev/sdc
...(jounral size is 32M)
# mount.ocfs2 /dev/sdc /mnt/ocfs2/
# touch /mnt/ocfs2/1.log
# fallocate -o 0 -l 400G /mnt/ocfs2/1.log
fallocate: /mnt/ocfs2/1.log: fallocate failed: Cannot allocate memory
# tail -f /var/log/messages
[ 7372.278591] JBD: fallocate wants too many credits (2051 > 2048)
[ 7372.278597] (fallocate,6438,0):__ocfs2_extend_allocation:709 ERROR: status = -12
[ 7372.278603] (fallocate,6438,0):ocfs2_allocate_unwritten_extents:1504 ERROR: status = -12
[ 7372.278607] (fallocate,6438,0):__ocfs2_change_file_space:1955 ERROR: status = -12
^C
With this patch, the test works well.
Signed-off-by: NYounger Liu <younger.liu@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the corresponding trace event for trim.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>

Remove mlog(0,...) and mlog(ML_UPTODATE,...) from
fs/ocfs2/uptodate.c and fs/ocfs2/buffer_head_io.c.

The masklog UPTODATE is removed finally.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0,...) and mlog(ML_BH_IO,...) from
fs/ocfs2/buffer_head_io.c.
The masklog BH_IO is removed finally.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/journal.c and the masklog JOURNAL.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/export.c and the masklog EXPORT.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/dcache.c and the masklog DCACHE.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/namei.c and the masklog NAMEI finally.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 2nd step to remove the debug info of NAMEI.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/quota_global.c and
the masklog QUOTA.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/quota_local.c.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/reservations.c and the masklog RESERVATIONS.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/xattr.c and the masklog ML_XATTR.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/super.c and the masklog SUPER.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 2nd step to remove the debug info of SUPER.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 1st step to remove the debug info of SUPER.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/extent_map.c and the masklog EXTENT_MAP.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove mlog(0) from fs/ocfs2/inode.c and the masklog INODE.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 2nd step to remove the debug info of INODE.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Change all the "mlog(0," in fs/ocfs2/mmap.c to trace events.
And finally remove masklog FILE_IO.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Remove all the "mlog(0," in fs/ocfs2/aops.c.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

Change all the "mlog(0," in fs/ocfs2/refcounttree.c to trace events.
And finally remove masklog ML_REFCOUNT.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 4th step to remove the debug info of DISK_ALLOC.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 3rd step to remove the debug info of DISK_ALLOC.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the 2nd step to remove the debug info of DISK_ALLOC.

So this patch removes all mlog(0,...) from localalloc.c and adds
the corresponding tracepoints. Different mlogs have different
solutions.
1. Some are replaced with trace event directly.
2. Some are replaced while some new parameters are added.
3. Some are combined into one trace events.
4. Some redundant mlogs are removed.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

This is the first try of replacing debug mlog(0,...) to
trace events. Wengang has did some work in his original
patch
http://oss.oracle.com/pipermail/ocfs2-devel/2009-November/005513.html
But he didn't finished it.

So this patch removes all mlog(0,...) from alloc.c and adds
the corresponding trace events. Different mlogs have different
solutions.
1. Some are replaced with trace event directly.
2. Some are replaced and some new parameters are added since
   I think we need to know the btree owner in that case.
3. Some are combined into one trace events.
4. Some redundant mlogs are removed.
What's more, it defines some event classes so that we can use
them later.

Cc: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

About one year ago, Wengang Wang tried some first steps
to add tracepoints to ocfs2. Hiss original patch is here:
http://oss.oracle.com/pipermail/ocfs2-devel/2009-November/005512.html

But as Steven Rostedt indicated in his article
http://lwn.net/Articles/383362/, we'd better have our trace
files resides in fs/ocfs2, so I rewrited the patch using the
method Steven mentioned in that article.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: NTao Ma <boyu.mt@taobao.com>