[PATCH 10/10] afs: Don't invoke the server to read data beyond EOF

From: David Howells
Date: Mon Aug 06 2018 - 09:17:50 EST


When writing a new page, clear space in the page rather than attempting to
load it from the server if the space is beyond the EOF.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/afs/write.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 6ff0f25836de..7c7a03310f16 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -33,10 +33,21 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
loff_t pos, unsigned int len, struct page *page)
{
struct afs_read *req;
+ size_t p;
+ void *data;
int ret;

_enter(",,%llu", (unsigned long long)pos);

+ if (pos >= vnode->vfs_inode.i_size) {
+ p = pos & ~PAGE_MASK;
+ ASSERTCMP(p + len, <=, PAGE_SIZE);
+ data = kmap(page);
+ memset(data + p, 0, len);
+ kunmap(page);
+ return 0;
+ }
+
req = kzalloc(sizeof(struct afs_read), GFP_KERNEL);
if (!req)
return -ENOMEM;