Re: [NFS] [PATCH] mmap corruption

[Trond Myklebust <trond.myklebust@fys.uio.no>]

>>>>> " " == Steve Dickson <SteveD@RedHat.com> writes:

     > 	filemap_fdatasync(inode->i_mapping);
     > 	error = nfs_wb_all(inode);
     > 	filemap_fdatawait(inode->i_mapping);
     > 	if (error)
     > 		goto out;

     > 	/*
     > * Every time either npages or ncommit had a value and the file
     > 	   size is
     > * immediately changed (with in a microsecond or two) by another
     > * truncation, followed by a mmap read, the file would be
     > 	   corrupted.
     > 	 */
     > 	if (NFS_I(inode)->npages || NFS_I(inode)->ncommit ||
     > 	NFS_I(inode)->ndirty) {
     > 		printk("nfs_notify_change: fid %Ld npages %d ncommit
     > 		%d ndirty %d\n", NFS_FILEID(inode),
     > 		NFS_I(inode)->npages, ncommit, NFS_I(inode)->ndirty);
     > 	}
     > }

My point is that nfs_wb_all() is supposed to ensure that
NFS_I(inode)->ncommit, and/or NFS_I(inode)->ndirty are both
zero. i.e. you can have pending reads (in which case
NFS_I(inode)->npages != 0), but *no* pending writes.

Was this the case?

Cheers,
  Trond