Description of Problem:
The routine fsync_inode_buffers() should write out the dirty buffers for the
specified inode, but there exists a scenario where it can return having failed
to do so:
bdflush() runs and gets its hands on a dirty buffer. It locks, cleans, and
submits it.  Before the I/O completes, commit_write() dirties it again.
Now fsync_inode_buffers() runs.  It sees the buffer as dirty, so it calls
ll_rw_block() on it, but its try lock fails, so it does nothing.
fsync_inode_buffers() later waits on the buffer.  Then the I/O finally
completes, and fsync_inode_buffers() returns.  That I/O was on a previous
version of the block -- the latest data have not necessarily reached the disk yet.

Version-Release number of selected component (if applicable):
2.4.9-e.3, e.5 and e.8

How Reproducible:
100%

Steps to Reproduce:
1. This is a race condition. We encountered it in work on a shared/clustered
filesystem. Corruption occurred and the bug was found through inspection.
2. 
3. 

Actual Results:
Occasionally, not all buffers will be flushed when fsync_inode_buffers returns.
In a clustered filesystem, this can cause data corruption.

Expected Results:
All dirty buffers should have been written at least in the form they were at the
time of the call on return from fsync_inode_buffers.

Additional Information:
	
This causes data corruption for a shared/clustered filesytem which needs to use
clusterwide inode locks and expects fsync_inode_buffers() reliably write all the
dirty buffers.