nfs: increment i_dio_count for reads, too

i_dio_count is used to protect dio access against truncate.  We want
to make sure there are no dio reads pending either when doing a
truncate.  I suspect on plain NFS things might work even without
this, but once we use a pnfs layout driver that access backing devices
directly things will go bad without the proper synchronization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 75ed2a9..6c23210 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -235,10 +235,10 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq, bool write)
                spin_unlock(&inode->i_lock);
        }
 
-       if (write) {
+       if (write)
                nfs_zap_mapping(inode, inode->i_mapping);
-               inode_dio_done(inode);
-       }
+
+       inode_dio_done(inode);
 
        if (dreq->iocb) {
                long res = (long) dreq->error;
@@ -419,6 +419,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
                                              loff_t pos, bool uio)
 {
        struct nfs_pageio_descriptor desc;
+       struct inode *inode = dreq->inode;
        ssize_t result = -EINVAL;
        size_t requested_bytes = 0;
        unsigned long seg;
@@ -427,6 +428,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
                             &nfs_direct_read_completion_ops);
        get_dreq(dreq);
        desc.pg_dreq = dreq;
+       atomic_inc(&inode->i_dio_count);
 
        for (seg = 0; seg < nr_segs; seg++) {
                const struct iovec *vec = &iov[seg];
@@ -446,6 +448,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
         * generic layer handle the completion.
         */
        if (requested_bytes == 0) {
+               inode_dio_done(inode);
                nfs_direct_req_release(dreq);
                return result < 0 ? result : -EIO;
        }