[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>

3 files changed, 9 insertions, 5 deletions

diff --git a/fs/exec.c b/fs/exec.c
index ce76b33..cd6c574 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1511,7 +1511,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 		goto close_fail;
 	if (!file->f_op->write)
 		goto close_fail;
-	if (do_truncate(file->f_dentry, 0) != 0)
+	if (do_truncate(file->f_dentry, 0, file) != 0)
 		goto close_fail;
 
 	retval = binfmt->core_dump(signr, regs, file);
diff --git a/fs/namei.c b/fs/namei.c
index c5769c4..b3f8a19 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1459,7 +1459,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
 		if (!error) {
 			DQUOT_INIT(inode);
 			
-			error = do_truncate(dentry, 0);
+			error = do_truncate(dentry, 0, NULL);
 		}
 		put_write_access(inode);
 		if (error)
diff --git a/fs/open.c b/fs/open.c
index 2835f09..6e81367 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -194,7 +194,7 @@ out:
 	return error;
 }
 
-int do_truncate(struct dentry *dentry, loff_t length)
+int do_truncate(struct dentry *dentry, loff_t length, struct file *filp)
 {
 	int err;
 	struct iattr newattrs;
@@ -205,6 +205,10 @@ int do_truncate(struct dentry *dentry, loff_t length)
 
 	newattrs.ia_size = length;
 	newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
+	if (filp) {
+		newattrs.ia_file = filp;
+		newattrs.ia_valid |= ATTR_FILE;
+	}
 
 	down(&dentry->d_inode->i_sem);
 	err = notify_change(dentry, &newattrs);
@@ -262,7 +266,7 @@ static inline long do_sys_truncate(const char __user * path, loff_t length)
 	error = locks_verify_truncate(inode, NULL, length);
 	if (!error) {
 		DQUOT_INIT(inode);
-		error = do_truncate(nd.dentry, length);
+		error = do_truncate(nd.dentry, length, NULL);
 	}
 	put_write_access(inode);
 
@@ -314,7 +318,7 @@ static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 
 	error = locks_verify_truncate(inode, file, length);
 	if (!error)
-		error = do_truncate(dentry, length);
+		error = do_truncate(dentry, length, file);
 out_putf:
 	fput(file);
 out: