NFS: Don't zap caches on fallocate()

This patch adds a GETATTR to the end of ALLOCATE and DEALLOCATE
operations so we can set the updated inode size and change attribute
directly. DEALLOCATE will still need to release pagecache pages, so
nfs42_proc_deallocate() now calls truncate_pagecache_range() before
contacting the server.

Signed-off-by: Anna Schumaker <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/inode.c

···
 	nfs_zap_caches_locked(inode);
 	spin_unlock(&inode->i_lock);
 }
-EXPORT_SYMBOL_GPL(nfs_zap_caches);
 
 void nfs_zap_mapping(struct inode *inode, struct address_space *mapping)
 {

fs/nfs/nfs42proc.c

···
 				 loff_t offset, loff_t len)
 {
 	struct inode *inode = file_inode(filep);
+	struct nfs_server *server = NFS_SERVER(inode);
 	struct nfs42_falloc_args args = {
 		.falloc_fh	= NFS_FH(inode),
 		.falloc_offset	= offset,
 		.falloc_length	= len,
+		.falloc_bitmask	= server->cache_consistency_bitmask,
 	};
-	struct nfs42_falloc_res res;
-	struct nfs_server *server = NFS_SERVER(inode);
+	struct nfs42_falloc_res res = {
+		.falloc_server	= server,
+	};
 	int status;
 
 	msg->rpc_argp = &args;
···
 	if (status)
 		return status;
 
-	return nfs4_call_sync(server->client, server, msg,
-			      &args.seq_args, &res.seq_res, 0);
+	res.falloc_fattr = nfs_alloc_fattr();
+	if (!res.falloc_fattr)
+		return -ENOMEM;
+
+	status = nfs4_call_sync(server->client, server, msg,
+				&args.seq_args, &res.seq_res, 0);
+	if (status == 0)
+		status = nfs_post_op_update_inode(inode, res.falloc_fattr);
+
+	kfree(res.falloc_fattr);
+	return status;
 }
 
 static int nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
···
 	if (!nfs_server_capable(inode, NFS_CAP_DEALLOCATE))
 		return -EOPNOTSUPP;
 
+	nfs_wb_all(inode);
 	err = nfs42_proc_fallocate(&msg, filep, offset, len);
+	if (err == 0)
+		truncate_pagecache_range(inode, offset, (offset + len) -1);
 	if (err == -EOPNOTSUPP)
 		NFS_SERVER(inode)->caps &= ~NFS_CAP_DEALLOCATE;
 	return err;

fs/nfs/nfs42xdr.c

···
 
 #define NFS4_enc_allocate_sz		(compound_encode_hdr_maxsz + \
 					 encode_putfh_maxsz + \
-					 encode_allocate_maxsz)
+					 encode_allocate_maxsz + \
+					 encode_getattr_maxsz)
 #define NFS4_dec_allocate_sz		(compound_decode_hdr_maxsz + \
 					 decode_putfh_maxsz + \
-					 decode_allocate_maxsz)
+					 decode_allocate_maxsz + \
+					 decode_getattr_maxsz)
 #define NFS4_enc_deallocate_sz		(compound_encode_hdr_maxsz + \
 					 encode_putfh_maxsz + \
-					 encode_deallocate_maxsz)
+					 encode_deallocate_maxsz + \
+					 encode_getattr_maxsz)
 #define NFS4_dec_deallocate_sz		(compound_decode_hdr_maxsz + \
 					 decode_putfh_maxsz + \
-					 decode_deallocate_maxsz)
+					 decode_deallocate_maxsz + \
+					 decode_getattr_maxsz)
 #define NFS4_enc_seek_sz		(compound_encode_hdr_maxsz + \
 					 encode_putfh_maxsz + \
 					 encode_seek_maxsz)
···
 	encode_sequence(xdr, &args->seq_args, &hdr);
 	encode_putfh(xdr, args->falloc_fh, &hdr);
 	encode_allocate(xdr, args, &hdr);
+	encode_getfattr(xdr, args->falloc_bitmask, &hdr);
 	encode_nops(&hdr);
 }
 
···
 	encode_sequence(xdr, &args->seq_args, &hdr);
 	encode_putfh(xdr, args->falloc_fh, &hdr);
 	encode_deallocate(xdr, args, &hdr);
+	encode_getfattr(xdr, args->falloc_bitmask, &hdr);
 	encode_nops(&hdr);
 }
 
···
 	if (status)
 		goto out;
 	status = decode_allocate(xdr, res);
+	if (status)
+		goto out;
+	decode_getfattr(xdr, res->falloc_fattr, res->falloc_server);
 out:
 	return status;
 }
···
 	if (status)
 		goto out;
 	status = decode_deallocate(xdr, res);
+	if (status)
+		goto out;
+	decode_getfattr(xdr, res->falloc_fattr, res->falloc_server);
 out:
 	return status;
 }

fs/nfs/nfs4file.c

···
 		ret = nfs42_proc_allocate(filep, offset, len);
 	mutex_unlock(&inode->i_mutex);
 
-	nfs_zap_caches(inode);
 	return ret;
 }
 #endif /* CONFIG_NFS_V4_2 */

include/linux/nfs_xdr.h

···
 	nfs4_stateid			 falloc_stateid;
 	u64				 falloc_offset;
 	u64				 falloc_length;
+	const u32			*falloc_bitmask;
 };
 
 struct nfs42_falloc_res {
 	struct nfs4_sequence_res	seq_res;
 	unsigned int			status;
+
+	struct nfs_fattr		*falloc_fattr;
+	const struct nfs_server		*falloc_server;
 };
 
 struct nfs42_seek_args {