Commit 5a14696c authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Al Viro
Browse files

locks: helper functions for delegation breaking 



We'll need the same logic for rename and link.

Acked-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b21996e3

fs/namei.c

+3 −10
Original line number Diff line number Diff line
@@ -3650,14 +3650,9 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate 
	else {

		error = security_inode_unlink(dir, dentry);

		if (!error) {

			error = break_deleg(target, O_WRONLY|O_NONBLOCK);

			if (error) {

				if (error == -EWOULDBLOCK && delegated_inode) {

					*delegated_inode = target;

					ihold(target);

				}

			error = try_break_deleg(target, delegated_inode);

			if (error)

				goto out;

			}

			error = dir->i_op->unlink(dir, dentry);

			if (!error)

				dont_mount(dentry);
@@ -3727,9 +3722,7 @@ static long do_unlinkat(int dfd, const char __user *pathname) 
		iput(inode);	/* truncate the inode here */

	inode = NULL;

	if (delegated_inode) {

		error = break_deleg(delegated_inode, O_WRONLY);

		iput(delegated_inode);

		delegated_inode = NULL;

		error = break_deleg_wait(&delegated_inode);

		if (!error)

			goto retry_deleg;

	}

include/linux/fs.h

+37 −2
Original line number Diff line number Diff line
@@ -1905,6 +1905,9 @@ extern bool fs_fully_visible(struct file_system_type *); 


extern int current_umask(void);



extern void ihold(struct inode * inode);

extern void iput(struct inode *);



/* /sys/fs */

extern struct kobject *fs_kobj;
@@ -1972,6 +1975,28 @@ static inline int break_deleg(struct inode *inode, unsigned int mode) 
	return 0;

}



static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)

{

	int ret;



	ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);

	if (ret == -EWOULDBLOCK && delegated_inode) {

		*delegated_inode = inode;

		ihold(inode);

	}

	return ret;

}



static inline int break_deleg_wait(struct inode **delegated_inode)

{

	int ret;



	ret = break_deleg(*delegated_inode, O_WRONLY);

	iput(*delegated_inode);

	*delegated_inode = NULL;

	return ret;

}



#else /* !CONFIG_FILE_LOCKING */

static inline int locks_mandatory_locked(struct inode *inode)

{
@@ -2015,6 +2040,18 @@ static inline int break_deleg(struct inode *inode, unsigned int mode) 
{

	return 0;

}



static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)

{

	return 0;

}



static inline int break_deleg_wait(struct inode **delegated_inode)

{

	BUG();

	return 0;

}



#endif /* CONFIG_FILE_LOCKING */



/* fs/open.c */
@@ -2350,8 +2387,6 @@ extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence); 
extern int inode_init_always(struct super_block *, struct inode *);

extern void inode_init_once(struct inode *);

extern void address_space_init_once(struct address_space *mapping);

extern void ihold(struct inode * inode);

extern void iput(struct inode *);

extern struct inode * igrab(struct inode *);

extern ino_t iunique(struct super_block *, ino_t);

extern int inode_needs_sync(struct inode *inode);