NFSv4/pnfs: Ensure we don't miss a file extension

pNFS writes don't return attributes, however that doesn't mean that we
should ignore the fact that they may be extending the file. This patch
ensures that if a write is seen to extend the file, then we always set
an attribute barrier, and update the cached file size.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 359e9ad596c9..0e6a2b8786b4 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1378,24 +1378,27 @@ static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
 {
         struct nfs_pgio_args *argp = &hdr->args;
         struct nfs_pgio_res *resp = &hdr->res;
+        u64 size = argp->offset + resp->count;
 
         if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
+                fattr->size = size;
+        if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
+                fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
                 return;
-        if (argp->offset + resp->count != fattr->size)
-                return;
-        if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode))
+        }
+        if (size != fattr->size)
                 return;
         /* Set attribute barrier */
         nfs_fattr_set_barrier(fattr);
+        /* ...and update size */
+        fattr->valid |= NFS_ATTR_FATTR_SIZE;
 }
 
 void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
 {
-        struct nfs_fattr *fattr = hdr->res.fattr;
+        struct nfs_fattr *fattr = &hdr->fattr;
         struct inode *inode = hdr->inode;
 
-        if (fattr == NULL)
-                return;
         spin_lock(&inode->i_lock);
         nfs_writeback_check_extend(hdr, fattr);
         nfs_post_op_update_inode_force_wcc_locked(inode, fattr);