2 files changed, 30 insertions, 9 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 672b187def62..dfd125798791 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -51,23 +51,23 @@ static loff_t lseek_execute(struct file *file, struct inode *inode,
 }
 
 /**
- * generic_file_llseek - generic llseek implementation for regular files
+ * generic_file_llseek_size - generic llseek implementation for regular files
  * @file:       file structure to seek on
  * @offset:     file offset to seek to
  * @origin:     type of seek
+ * @size:       max size of file system
  *
- * This is a generic implemenation of ->llseek usable for all normal local
- * filesystems.  It just updates the file offset to the value specified by
- * @offset and @origin under i_mutex.
+ * This is a variant of generic_file_llseek that allows passing in a custom
+ * file size.
  *
  * Synchronization:
- * SEEK_SET is unsynchronized (but atomic on 64bit platforms)
+ * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
  * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
  * read/writes behave like SEEK_SET against seeks.
- * SEEK_END
  */
 loff_t
-generic_file_llseek(struct file *file, loff_t offset, int origin)
+generic_file_llseek_size(struct file *file, loff_t offset, int origin,
+                loff_t maxsize)
 {
         struct inode *inode = file->f_mapping->host;
 
@@ -91,7 +91,7 @@ generic_file_llseek(struct file *file, loff_t offset, int origin)
                  */
                 spin_lock(&file->f_lock);
                 offset = lseek_execute(file, inode, file->f_pos + offset,
-                                       inode->i_sb->s_maxbytes);
+                                       maxsize);
                 spin_unlock(&file->f_lock);
                 return offset;
         case SEEK_DATA:
@@ -113,7 +113,26 @@ generic_file_llseek(struct file *file, loff_t offset, int origin)
                 break;
         }
 
-        return lseek_execute(file, inode, offset, inode->i_sb->s_maxbytes);
+        return lseek_execute(file, inode, offset, maxsize);
+}
+EXPORT_SYMBOL(generic_file_llseek_size);
+
+/**
+ * generic_file_llseek - generic llseek implementation for regular files
+ * @file:       file structure to seek on
+ * @offset:     file offset to seek to
+ * @origin:     type of seek
+ *
+ * This is a generic implemenation of ->llseek useable for all normal local
+ * filesystems.  It just updates the file offset to the value specified by
+ * @offset and @origin under i_mutex.
+ */
+loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
+{
+        struct inode *inode = file->f_mapping->host;
+
+        return generic_file_llseek_size(file, offset, origin,
+                                        inode->i_sb->s_maxbytes);
 }
 EXPORT_SYMBOL(generic_file_llseek);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index db85196f6308..d055cc7d7240 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2403,6 +2403,8 @@ file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
 extern loff_t noop_llseek(struct file *file, loff_t offset, int origin);
 extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
+extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
+                int origin, loff_t maxsize);
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);