Commit c45198ed authored by Jeff Layton's avatar Jeff Layton
Browse files

locks: move freeing of leases outside of i_lock 



There was only one place where we still could free a file_lock while
holding the i_lock -- lease_modify. Add a new list_head argument to the
lm_change operation, pass in a private list when calling it, and fix
those callers to dispose of the list once the lock has been dropped.

Signed-off-by: default avatarJeff Layton <jlayton@primarydata.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent f82b4b67

Documentation/filesystems/Locking

+1 −2
Original line number Diff line number Diff line
@@ -469,8 +469,7 @@ prototypes: 
};



locking rules:

	All may block except for ->setlease.

	No VFS locks held on entry except for ->setlease.

	All may block.



->llseek() locking has moved from llseek to the individual llseek

implementations.  If your fs is not using generic_file_llseek, you

fs/locks.c

+22 −12
Original line number Diff line number Diff line
@@ -1292,7 +1292,7 @@ static void lease_clear_pending(struct file_lock *fl, int arg) 
}



/* We already had a lease on this file; just change its type */

int lease_modify(struct file_lock **before, int arg)

int lease_modify(struct file_lock **before, int arg, struct list_head *dispose)

{

	struct file_lock *fl = *before;

	int error = assign_type(fl, arg);
@@ -1311,7 +1311,7 @@ int lease_modify(struct file_lock **before, int arg) 
			printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);

			fl->fl_fasync = NULL;

		}

		locks_delete_lock(before, NULL);

		locks_delete_lock(before, dispose);

	}

	return 0;

}
@@ -1325,7 +1325,7 @@ static bool past_time(unsigned long then) 
	return time_after(jiffies, then);

}



static void time_out_leases(struct inode *inode)

static void time_out_leases(struct inode *inode, struct list_head *dispose)

{

	struct file_lock **before;

	struct file_lock *fl;
@@ -1336,9 +1336,9 @@ static void time_out_leases(struct inode *inode) 
	while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {

		trace_time_out_leases(inode, fl);

		if (past_time(fl->fl_downgrade_time))

			lease_modify(before, F_RDLCK);

			lease_modify(before, F_RDLCK, dispose);

		if (past_time(fl->fl_break_time))

			lease_modify(before, F_UNLCK);

			lease_modify(before, F_UNLCK, dispose);

		if (fl == *before)	/* lease_modify may have freed fl */

			before = &fl->fl_next;

	}
@@ -1373,6 +1373,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) 
	int i_have_this_lease = 0;

	bool lease_conflict = false;

	int want_write = (mode & O_ACCMODE) != O_RDONLY;

	LIST_HEAD(dispose);



	new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);

	if (IS_ERR(new_fl))
@@ -1381,7 +1382,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) 


	spin_lock(&inode->i_lock);



	time_out_leases(inode);

	time_out_leases(inode, &dispose);



	flock = inode->i_flock;

	if ((flock == NULL) || !IS_LEASE(flock))
@@ -1436,6 +1437,7 @@ restart: 
	locks_insert_block(flock, new_fl);

	trace_break_lease_block(inode, new_fl);

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

	error = wait_event_interruptible_timeout(new_fl->fl_wait,

						!new_fl->fl_next, break_time);

	spin_lock(&inode->i_lock);
@@ -1443,7 +1445,7 @@ restart: 
	locks_delete_block(new_fl);

	if (error >= 0) {

		if (error == 0)

			time_out_leases(inode);

			time_out_leases(inode, &dispose);

		/*

		 * Wait for the next conflicting lease that has not been

		 * broken yet
@@ -1458,6 +1460,7 @@ restart: 


out:

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

	locks_free_lock(new_fl);

	return error;

}
@@ -1522,9 +1525,10 @@ int fcntl_getlease(struct file *filp) 
	struct file_lock *fl;

	struct inode *inode = file_inode(filp);

	int type = F_UNLCK;

	LIST_HEAD(dispose);



	spin_lock(&inode->i_lock);

	time_out_leases(file_inode(filp));

	time_out_leases(file_inode(filp), &dispose);

	for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);

			fl = fl->fl_next) {

		if (fl->fl_file == filp) {
@@ -1533,6 +1537,7 @@ int fcntl_getlease(struct file *filp) 
		}

	}

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

	return type;

}
@@ -1570,6 +1575,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr 
	struct inode *inode = dentry->d_inode;

	bool is_deleg = (*flp)->fl_flags & FL_DELEG;

	int error;

	LIST_HEAD(dispose);



	lease = *flp;

	trace_generic_add_lease(inode, lease);
@@ -1593,7 +1599,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr 
	}



	spin_lock(&inode->i_lock);

	time_out_leases(inode);

	time_out_leases(inode, &dispose);

	error = check_conflicting_open(dentry, arg);

	if (error)

		goto out;
@@ -1630,7 +1636,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr 


	if (my_before != NULL) {

		lease = *my_before;

		error = lease->fl_lmops->lm_change(my_before, arg);

		error = lease->fl_lmops->lm_change(my_before, arg, &dispose);

		if (error)

			goto out;

		goto out_setup;
@@ -1660,6 +1666,7 @@ out_setup: 
		lease->fl_lmops->lm_setup(lease, priv);

out:

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

	if (is_deleg)

		mutex_unlock(&inode->i_mutex);

	if (!error && !my_before)
@@ -1676,8 +1683,10 @@ static int generic_delete_lease(struct file *filp) 
	struct file_lock *fl, **before;

	struct dentry *dentry = filp->f_path.dentry;

	struct inode *inode = dentry->d_inode;

	LIST_HEAD(dispose);



	spin_lock(&inode->i_lock);

	time_out_leases(inode, &dispose);

	for (before = &inode->i_flock;

			((fl = *before) != NULL) && IS_LEASE(fl);

			before = &fl->fl_next) {
@@ -1686,8 +1695,9 @@ static int generic_delete_lease(struct file *filp) 
	}

	trace_generic_delete_lease(inode, fl);

	if (fl)

		error = fl->fl_lmops->lm_change(before, F_UNLCK);

		error = fl->fl_lmops->lm_change(before, F_UNLCK, &dispose);

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

	return error;

}
@@ -2372,7 +2382,7 @@ void locks_remove_file(struct file *filp) 
	while ((fl = *before) != NULL) {

		if (fl->fl_file == filp) {

			if (IS_LEASE(fl)) {

				lease_modify(before, F_UNLCK);

				lease_modify(before, F_UNLCK, &dispose);

				continue;

			}

fs/nfsd/nfs4state.c

+3 −3
Original line number Diff line number Diff line
@@ -3427,11 +3427,11 @@ static void nfsd_break_deleg_cb(struct file_lock *fl) 
	spin_unlock(&fp->fi_lock);

}



static

int nfsd_change_deleg_cb(struct file_lock **onlist, int arg)

static int

nfsd_change_deleg_cb(struct file_lock **onlist, int arg, struct list_head *dispose)

{

	if (arg & F_UNLCK)

		return lease_modify(onlist, arg);

		return lease_modify(onlist, arg, dispose);

	else

		return -EAGAIN;

}

include/linux/fs.h

+4 −3
Original line number Diff line number Diff line
@@ -873,7 +873,7 @@ struct lock_manager_operations { 
	void (*lm_notify)(struct file_lock *);	/* unblock callback */

	int (*lm_grant)(struct file_lock *, int);

	void (*lm_break)(struct file_lock *);

	int (*lm_change)(struct file_lock **, int);

	int (*lm_change)(struct file_lock **, int, struct list_head *);

	void (*lm_setup)(struct file_lock *, void **);

};
@@ -985,7 +985,7 @@ extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int t 
extern void lease_get_mtime(struct inode *, struct timespec *time);

extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);

extern int vfs_setlease(struct file *, long, struct file_lock **, void **);

extern int lease_modify(struct file_lock **, int);

extern int lease_modify(struct file_lock **, int, struct list_head *);

#else /* !CONFIG_FILE_LOCKING */

static inline int fcntl_getlk(struct file *file, unsigned int cmd,

			      struct flock __user *user)
@@ -1112,7 +1112,8 @@ static inline int vfs_setlease(struct file *filp, long arg, 
	return -EINVAL;

}



static inline int lease_modify(struct file_lock **before, int arg)

static inline int lease_modify(struct file_lock **before, int arg,

			       struct list_head *dispose)

{

	return -EINVAL;

}

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