[PATCH] VFS: pass file pointer to filesystem from ftruncate()

This patch extends the iattr structure with a file pointer memeber, and adds
an ATTR_FILE validity flag for this member.

This is set if do_truncate() is invoked from ftruncate() or from
do_coredump().

The change is source and binary compatible.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6d6226732c93..0c89fc9481a8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -264,6 +264,7 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define ATTR_ATTR_FLAG  1024
 #define ATTR_KILL_SUID  2048
 #define ATTR_KILL_SGID  4096
+#define ATTR_FILE       8192
 
 /*
  * This is the Inode Attributes structure, used for notify_change().  It
@@ -283,6 +284,13 @@ struct iattr {
         struct timespec ia_atime;
         struct timespec ia_mtime;
         struct timespec ia_ctime;
+
+        /*
+         * Not an attribute, but an auxilary info for filesystems wanting to
+         * implement an ftruncate() like method.  NOTE: filesystem should
+         * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
+         */
+        struct file     *ia_file;
 };
 
 /*
@@ -1288,7 +1296,7 @@ static inline int break_lease(struct inode *inode, unsigned int mode)
 
 /* fs/open.c */
 
-extern int do_truncate(struct dentry *, loff_t start);
+extern int do_truncate(struct dentry *, loff_t start, struct file *filp);
 extern long do_sys_open(const char __user *filename, int flags, int mode);
 extern struct file *filp_open(const char *, int, int);
 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);