9p: Fix the incorrect update of inode size in v9fs_file_write()

When using the cache=loose flags, the inode's size was not being
updated correctly on a remote write. Thus subsequent reads of
the whole file resulted in a truncated read. Fix it.

Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index de7690eec4d8..cafaa46434ba 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -32,6 +32,7 @@
 #include <linux/string.h>
 #include <linux/inet.h>
 #include <linux/list.h>
+#include <linux/pagemap.h>
 #include <asm/uaccess.h>
 #include <linux/idr.h>
 #include <net/9p/9p.h>
@@ -210,6 +211,7 @@ v9fs_file_write(struct file *filp, const char __user * data,
         struct p9_client *clnt;
         struct inode *inode = filp->f_path.dentry->d_inode;
         int origin = *offset;
+        unsigned long pg_start, pg_end;
 
         P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
                 (int)count, (int)*offset);
@@ -225,7 +227,7 @@ v9fs_file_write(struct file *filp, const char __user * data,
                 if (count < rsize)
                         rsize = count;
 
-                n = p9_client_write(fid, NULL, data+total, *offset+total,
+                n = p9_client_write(fid, NULL, data+total, origin+total,
                                                                         rsize);
                 if (n <= 0)
                         break;
@@ -234,13 +236,12 @@ v9fs_file_write(struct file *filp, const char __user * data,
         } while (count > 0);
 
         if (total > 0) {
-                invalidate_inode_pages2_range(inode->i_mapping, origin,
-                                                                origin+total);
+                pg_start = origin >> PAGE_CACHE_SHIFT;
+                pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
+                invalidate_inode_pages2_range(inode->i_mapping, pg_start,
+                                                                pg_end);
                 *offset += total;
-        }
-
-        if (*offset > i_size_read(inode)) {
-                i_size_write(inode, *offset);
+                i_size_write(inode, i_size_read(inode) + total);
                 inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
         }