Re: invalidate_inode_pages in 2.5.32/3

Trond Myklebust
2002-09-05T20:46:58Z

>>>>> " " == Andrew Morton <akpm@zip.com.au> writes:

> Probably, it worked OK with the global locking because nobody
> was taking a temp ref against those pages.

But we still have global locking in that readdir by means of the
BKL. There should be no nasty races...

> Please tell me exactly what semantics NFS needs in there. Does
> truncate_inode_pages() do the wrong thing?

Definitely. In most cases we *cannot* wait on I/O completion because
nfs_zap_caches() can be called directly from the 'rpciod' process by
means of a callback. Since 'rpciod' is responsible for completing all
asynchronous I/O, then truncate_inode_pages() would deadlock.

As I said: I don't believe the problem here has anything to do with
invalidate_inode_pages vs. truncate_inode_pages:
- Pages should only be locked if they are actually being read from
the server.
- They should only be refcounted and/or cleared while the BKL is
held...
There is no reason why code which worked fine under 2.2.x and 2.4.x
shouldn't work under 2.5.x.

Cheers,
Trond