1 files changed, 32 insertions, 6 deletions

diff --git a/fs/fat/file.c b/fs/fat/file.c
index 7134403d5be2..e99c5a73b39e 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -6,11 +6,13 @@
  *  regular file handling primitives for fat-based filesystems
  */
 
+#include <linux/capability.h>
 #include <linux/module.h>
 #include <linux/time.h>
 #include <linux/msdos_fs.h>
 #include <linux/smp_lock.h>
 #include <linux/buffer_head.h>
+#include <linux/writeback.h>
 
 int fat_generic_ioctl(struct inode *inode, struct file *filp,
                       unsigned int cmd, unsigned long arg)
@@ -40,7 +42,7 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
                 if (err)
                         return err;
 
-                down(&inode->i_sem);
+                mutex_lock(&inode->i_mutex);
 
                 if (IS_RDONLY(inode)) {
                         err = -EROFS;
@@ -102,7 +104,7 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
                 MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
                 mark_inode_dirty(inode);
         up:
-                up(&inode->i_sem);
+                mutex_unlock(&inode->i_mutex);
                 return err;
         }
         default:
@@ -124,6 +126,24 @@ struct file_operations fat_file_operations = {
         .sendfile       = generic_file_sendfile,
 };
 
+static int fat_cont_expand(struct inode *inode, loff_t size)
+{
+        struct address_space *mapping = inode->i_mapping;
+        loff_t start = inode->i_size, count = size - inode->i_size;
+        int err;
+
+        err = generic_cont_expand_simple(inode, size);
+        if (err)
+                goto out;
+
+        inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+        mark_inode_dirty(inode);
+        if (IS_SYNC(inode))
+                err = sync_page_range_nolock(inode, mapping, start, count);
+out:
+        return err;
+}
+
 int fat_notify_change(struct dentry *dentry, struct iattr *attr)
 {
         struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
@@ -132,11 +152,17 @@ int fat_notify_change(struct dentry *dentry, struct iattr *attr)
 
         lock_kernel();
 
-        /* FAT cannot truncate to a longer file */
+        /*
+         * Expand the file. Since inode_setattr() updates ->i_size
+         * before calling the ->truncate(), but FAT needs to fill the
+         * hole before it.
+         */
         if (attr->ia_valid & ATTR_SIZE) {
                 if (attr->ia_size > inode->i_size) {
-                        error = -EPERM;
-                        goto out;
+                        error = fat_cont_expand(inode, attr->ia_size);
+                        if (error || attr->ia_valid == ATTR_SIZE)
+                                goto out;
+                        attr->ia_valid &= ~ATTR_SIZE;
                 }
         }
 
@@ -173,7 +199,7 @@ out:
         return error;
 }
 
-EXPORT_SYMBOL(fat_notify_change);
+EXPORT_SYMBOL_GPL(fat_notify_change);
 
 /* Free all clusters after the skip'th cluster. */
 static int fat_free(struct inode *inode, int skip)