NFS: Add attribute update barriers to NFS writebacks
Ensure that other operations that race with our write RPC calls
cannot revert the file size updates that were made on the server.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 595d81e..849ed78 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1377,6 +1377,36 @@
return 0;
}
+static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
+ struct nfs_fattr *fattr)
+{
+ struct nfs_pgio_args *argp = &hdr->args;
+ struct nfs_pgio_res *resp = &hdr->res;
+
+ if (!(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))
+ return;
+ /* Set attribute barrier */
+ nfs_fattr_set_barrier(fattr);
+}
+
+void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
+{
+ struct nfs_fattr *fattr = hdr->res.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);
+ spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
+
/*
* This function is called when the WRITE call is complete.
*/