3 files changed, 35 insertions, 5 deletions

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index e99705474dd1..70c925978d10 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -169,7 +169,7 @@ static void afs_apply_status(struct afs_operation *op,
 	struct timespec64 t;
 	umode_t mode;
 	bool data_changed = false;
-	bool change_size = false;
+	bool change_size = vp->set_size;
 
 	_enter("{%llx:%llu.%u} %s",
 	       vp->fid.vid, vp->fid.vnode, vp->fid.unique,
@@ -799,7 +799,15 @@ void afs_evict_inode(struct inode *inode)
 
 static void afs_setattr_success(struct afs_operation *op)
 {
+	struct inode *inode = &op->file[0].vnode->vfs_inode;
+
 	afs_vnode_commit_status(op, &op->file[0]);
+	if (op->setattr.attr->ia_valid & ATTR_SIZE) {
+		loff_t i_size = inode->i_size, size = op->setattr.attr->ia_size;
+		if (size > i_size)
+			pagecache_isize_extended(inode, i_size, size);
+		truncate_pagecache(inode, size);
+	}
 }
 
 static const struct afs_operation_ops afs_setattr_operation = {
@@ -815,6 +823,7 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
+	int ret;
 
 	_enter("{%llx:%llu},{n=%pd},%x",
 	       vnode->fid.vid, vnode->fid.vnode, dentry,
@@ -827,6 +836,18 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
 		return 0;
 	}
 
+	if (attr->ia_valid & ATTR_SIZE) {
+		if (!S_ISREG(vnode->vfs_inode.i_mode))
+			return -EISDIR;
+
+		ret = inode_newsize_ok(&vnode->vfs_inode, attr->ia_size);
+		if (ret)
+			return ret;
+
+		if (attr->ia_size == i_size_read(&vnode->vfs_inode))
+			attr->ia_valid &= ~ATTR_SIZE;
+	}
+
 	/* 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);
@@ -840,8 +861,10 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
 	afs_op_set_vnode(op, 0, vnode);
 	op->setattr.attr = attr;
 
-	if (attr->ia_valid & ATTR_SIZE)
+	if (attr->ia_valid & ATTR_SIZE) {
 		op->file[0].dv_delta = 1;
+		op->file[0].set_size = true;
+	}
 	op->ctime = attr->ia_ctime;
 	op->file[0].update_ctime = 1;
 
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 92cd6b8cc01f..bdc1e5efebd4 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -744,9 +744,10 @@ struct afs_vnode_param {
 	afs_dataversion_t	dv_before;	/* Data version before the call */
 	unsigned int		cb_break_before; /* cb_break + cb_s_break before the call */
 	u8			dv_delta;	/* Expected change in data version */
-	bool			put_vnode;	/* T if we have a ref on the vnode */
-	bool			need_io_lock;	/* T if we need the I/O lock on this */
-	bool			update_ctime;	/* Need to update the ctime */
+	bool			put_vnode:1;	/* T if we have a ref on the vnode */
+	bool			need_io_lock:1;	/* T if we need the I/O lock on this */
+	bool			update_ctime:1;	/* Need to update the ctime */
+	bool			set_size:1;	/* Must update i_size */
 };
 
 /*
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 2003d7ee9e43..7437806332d9 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -492,6 +492,7 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 	unsigned long count, priv;
 	unsigned n, offset, to, f, t;
 	pgoff_t start, first, last;
+	loff_t i_size, end;
 	int loop, ret;
 
 	_enter(",%lx", primary_page->index);
@@ -592,7 +593,12 @@ no_more:
 	first = primary_page->index;
 	last = first + count - 1;
 
+	end = (loff_t)last * PAGE_SIZE + to;
+	i_size = i_size_read(&vnode->vfs_inode);
+
 	_debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
+	if (end > i_size)
+		to = i_size & ~PAGE_MASK;
 
 	ret = afs_store_data(mapping, first, last, offset, to);
 	switch (ret) {