Commit 53b95d63 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'locks-v3.17-2' of git://git.samba.org/jlayton/linux 

Pull file locking bugfixes from Jeff Layton:
 "Most of these patches are to fix a long-standing regression that crept
  in when the BKL was removed from the file-locking code.  The code was
  converted to use a conventional spinlock, but some fl_release_private
  ops can block and you can end up sleeping inside the lock.

  There's also a patch to make /proc/locks show delegations as 'DELEG'"

* tag 'locks-v3.17-2' of git://git.samba.org/jlayton/linux:
  locks: update Locking documentation to clarify fl_release_private behavior
  locks: move locks_free_lock calls in do_fcntl_add_lease outside spinlock
  locks: defer freeing locks in locks_delete_lock until after i_lock has been dropped
  locks: don't reuse file_lock in __posix_lock_file
  locks: don't call locks_release_private from locks_copy_lock
  locks: show delegations as "DELEG" in /proc/locks
parents da06df54 2ece173e

Documentation/filesystems/Locking

+5 −1
Original line number Diff line number Diff line
@@ -349,7 +349,11 @@ prototypes: 
locking rules:

			inode->i_lock	may block

fl_copy_lock:		yes		no

fl_release_private:	maybe		no

fl_release_private:	maybe		maybe[1]



[1]:	->fl_release_private for flock or POSIX locks is currently allowed

to block. Leases however can still be freed while the i_lock is held and

so fl_release_private called on a lease should not block.



----------------------- lock_manager_operations ---------------------------

prototypes:

fs/locks.c

+57 −29
Original line number Diff line number Diff line
@@ -247,6 +247,18 @@ void locks_free_lock(struct file_lock *fl) 
}

EXPORT_SYMBOL(locks_free_lock);



static void

locks_dispose_list(struct list_head *dispose)

{

	struct file_lock *fl;



	while (!list_empty(dispose)) {

		fl = list_first_entry(dispose, struct file_lock, fl_block);

		list_del_init(&fl->fl_block);

		locks_free_lock(fl);

	}

}



void locks_init_lock(struct file_lock *fl)

{

	memset(fl, 0, sizeof(struct file_lock));
@@ -285,7 +297,8 @@ EXPORT_SYMBOL(__locks_copy_lock); 


void locks_copy_lock(struct file_lock *new, struct file_lock *fl)

{

	locks_release_private(new);

	/* "new" must be a freshly-initialized lock */

	WARN_ON_ONCE(new->fl_ops);



	__locks_copy_lock(new, fl);

	new->fl_file = fl->fl_file;
@@ -650,11 +663,15 @@ static void locks_unlink_lock(struct file_lock **thisfl_p) 
 *

 * Must be called with i_lock held!

 */

static void locks_delete_lock(struct file_lock **thisfl_p)

static void locks_delete_lock(struct file_lock **thisfl_p,

			      struct list_head *dispose)

{

	struct file_lock *fl = *thisfl_p;



	locks_unlink_lock(thisfl_p);

	if (dispose)

		list_add(&fl->fl_block, dispose);

	else

		locks_free_lock(fl);

}
@@ -811,6 +828,7 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) 
	struct inode * inode = file_inode(filp);

	int error = 0;

	int found = 0;

	LIST_HEAD(dispose);



	if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {

		new_fl = locks_alloc_lock();
@@ -833,7 +851,7 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) 
		if (request->fl_type == fl->fl_type)

			goto out;

		found = 1;

		locks_delete_lock(before);

		locks_delete_lock(before, &dispose);

		break;

	}
@@ -880,6 +898,7 @@ out: 
	spin_unlock(&inode->i_lock);

	if (new_fl)

		locks_free_lock(new_fl);

	locks_dispose_list(&dispose);

	return error;

}
@@ -893,6 +912,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str 
	struct file_lock **before;

	int error;

	bool added = false;

	LIST_HEAD(dispose);



	/*

	 * We may need two file_lock structures for this operation,
@@ -988,7 +1008,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str 
			else

				request->fl_end = fl->fl_end;

			if (added) {

				locks_delete_lock(before);

				locks_delete_lock(before, &dispose);

				continue;

			}

			request = fl;
@@ -1018,21 +1038,24 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str 
				 * one (This may happen several times).

				 */

				if (added) {

					locks_delete_lock(before);

					locks_delete_lock(before, &dispose);

					continue;

				}

				/* Replace the old lock with the new one.

				 * Wake up anybody waiting for the old one,

				 * as the change in lock type might satisfy

				 * their needs.

				/*

				 * Replace the old lock with new_fl, and

				 * remove the old one. It's safe to do the

				 * insert here since we know that we won't be

				 * using new_fl later, and that the lock is

				 * just replacing an existing lock.

				 */

				locks_wake_up_blocks(fl);

				fl->fl_start = request->fl_start;

				fl->fl_end = request->fl_end;

				fl->fl_type = request->fl_type;

				locks_release_private(fl);

				locks_copy_private(fl, request);

				request = fl;

				error = -ENOLCK;

				if (!new_fl)

					goto out;

				locks_copy_lock(new_fl, request);

				request = new_fl;

				new_fl = NULL;

				locks_delete_lock(before, &dispose);

				locks_insert_lock(before, request);

				added = true;

			}

		}
@@ -1093,6 +1116,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str 
		locks_free_lock(new_fl);

	if (new_fl2)

		locks_free_lock(new_fl2);

	locks_dispose_list(&dispose);

	return error;

}
@@ -1268,7 +1292,7 @@ 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);

		locks_delete_lock(before, NULL);

	}

	return 0;

}
@@ -1737,13 +1761,10 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg) 
	ret = fl;

	spin_lock(&inode->i_lock);

	error = __vfs_setlease(filp, arg, &ret);

	if (error) {

		spin_unlock(&inode->i_lock);

		locks_free_lock(fl);

		goto out_free_fasync;

	}

	if (ret != fl)

		locks_free_lock(fl);

	if (error)

		goto out_unlock;

	if (ret == fl)

		fl = NULL;



	/*

	 * fasync_insert_entry() returns the old entry if any.
@@ -1755,9 +1776,10 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg) 
		new = NULL;



	error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);

out_unlock:

	spin_unlock(&inode->i_lock);



out_free_fasync:

	if (fl)

		locks_free_lock(fl);

	if (new)

		fasync_free(new);

	return error;
@@ -2320,6 +2342,7 @@ void locks_remove_file(struct file *filp) 
	struct inode * inode = file_inode(filp);

	struct file_lock *fl;

	struct file_lock **before;

	LIST_HEAD(dispose);



	if (!inode->i_flock)

		return;
@@ -2365,12 +2388,13 @@ void locks_remove_file(struct file *filp) 
				fl->fl_type, fl->fl_flags,

				fl->fl_start, fl->fl_end);



			locks_delete_lock(before);

			locks_delete_lock(before, &dispose);

			continue;

 		}

		before = &fl->fl_next;

	}

	spin_unlock(&inode->i_lock);

	locks_dispose_list(&dispose);

}



/**
@@ -2452,7 +2476,11 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, 
			seq_puts(f, "FLOCK  ADVISORY  ");

		}

	} else if (IS_LEASE(fl)) {

		if (fl->fl_flags & FL_DELEG)

			seq_puts(f, "DELEG  ");

		else

			seq_puts(f, "LEASE  ");



		if (lease_breaking(fl))

			seq_puts(f, "BREAKING  ");

		else if (fl->fl_file)

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