[PATCH] invalidate_inode_pages2_range() debug

A failure in invalidate_inode_pages2_range() can result in unpleasant things
happening in NFS (at least).  Stick a WARN_ON_ONCE() in there so we can find
out if it happens, and maybe why.

(akpm: might be a -mm-only patch, we'll see..)

Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Steve Dickson <SteveD@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/truncate.c b/mm/truncate.c
index f4edbc179d14423e1f3acf9555b96bc9795b37bc..fca28839c46e895e6d137ca7497c98736be348bd 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -396,6 +396,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
                pagevec_release(&pvec);
                cond_resched();
        }
+       WARN_ON_ONCE(ret);
        return ret;
 }
 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);