1 files changed, 35 insertions, 10 deletions

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 8db902405031..5964f8aee090 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -848,42 +848,67 @@ static const struct afs_operation_ops afs_setattr_operation = {
 int afs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		struct iattr *attr)
 {
+	const unsigned int supported =
+		ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
+		ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET | ATTR_TOUCH;
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
+	struct inode *inode = &vnode->vfs_inode;
+	loff_t i_size;
 	int ret;
 
 	_enter("{%llx:%llu},{n=%pd},%x",
 	       vnode->fid.vid, vnode->fid.vnode, dentry,
 	       attr->ia_valid);
 
-	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
-				ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET |
-				ATTR_TOUCH))) {
+	if (!(attr->ia_valid & supported)) {
 		_leave(" = 0 [unsupported]");
 		return 0;
 	}
 
+	i_size = i_size_read(inode);
 	if (attr->ia_valid & ATTR_SIZE) {
-		if (!S_ISREG(vnode->vfs_inode.i_mode))
+		if (!S_ISREG(inode->i_mode))
 			return -EISDIR;
 
-		ret = inode_newsize_ok(&vnode->vfs_inode, attr->ia_size);
+		ret = inode_newsize_ok(inode, attr->ia_size);
 		if (ret)
 			return ret;
 
-		if (attr->ia_size == i_size_read(&vnode->vfs_inode))
+		if (attr->ia_size == i_size)
 			attr->ia_valid &= ~ATTR_SIZE;
 	}
 
 	fscache_use_cookie(afs_vnode_cache(vnode), true);
 
-	/* flush any dirty data outstanding on a regular file */
-	if (S_ISREG(vnode->vfs_inode.i_mode))
-		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
-
 	/* Prevent any new writebacks from starting whilst we do this. */
 	down_write(&vnode->validate_lock);
 
+	if ((attr->ia_valid & ATTR_SIZE) && S_ISREG(inode->i_mode)) {
+		loff_t size = attr->ia_size;
+
+		/* Wait for any outstanding writes to the server to complete */
+		loff_t from = min(size, i_size);
+		loff_t to = max(size, i_size);
+		ret = filemap_fdatawait_range(inode->i_mapping, from, to);
+		if (ret < 0)
+			goto out_unlock;
+
+		/* Don't talk to the server if we're just shortening in-memory
+		 * writes that haven't gone to the server yet.
+		 */
+		if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) &&
+		    attr->ia_size < i_size &&
+		    attr->ia_size > vnode->status.size) {
+			truncate_pagecache(inode, attr->ia_size);
+			fscache_resize_cookie(afs_vnode_cache(vnode),
+					      attr->ia_size);
+			i_size_write(inode, attr->ia_size);
+			ret = 0;
+			goto out_unlock;
+		}
+	}
+
 	op = afs_alloc_operation(((attr->ia_valid & ATTR_FILE) ?
 				  afs_file_key(attr->ia_file) : NULL),
 				 vnode->volume);