CIFS: cifs_writepages should not write beyond end of file

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 585a62aebd59..23af20d5af7c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1011,6 +1011,7 @@ static int cifs_writepages(struct address_space *mapping,
         pgoff_t index;
         int is_range = 0;
         struct kvec iov[32];
+        int len;
         int n_iov = 0;
         pgoff_t next;
         int nr_pages;
@@ -1124,16 +1125,26 @@ retry:
                                 unlock_page(page);
                                 break;
                         }
+
+                        if (page_offset(page) >= mapping->host->i_size) {
+                                done = 1;
+                                unlock_page(page);
+                                break;
+                        }
+
                         /*
                          * BB can we get rid of this?  pages are held by pvec
                          */
                         page_cache_get(page);
 
+                        len = min(mapping->host->i_size - page_offset(page),
+                                  (loff_t)PAGE_CACHE_SIZE);
+
                         /* reserve iov[0] for the smb header */
                         n_iov++;
                         iov[n_iov].iov_base = kmap(page);
-                        iov[n_iov].iov_len = PAGE_CACHE_SIZE;
-                        bytes_to_write += PAGE_CACHE_SIZE;
+                        iov[n_iov].iov_len = len;
+                        bytes_to_write += len;
 
                         if (first < 0) {
                                 first = i;