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Commit 0ceaf6c7 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Linus Torvalds
Browse files

locks: prevent ENOMEM on lease unlock 



Removing a lock shouldn't require any allocations; a failure due to
ENOMEM leaves the caller with a choice between retrying or giving up and
leaking an unused lease.

Next we should split the other lease calls into add and delete cases.
I wanted to start with just the bugfix.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0d07025e

fs/locks.c

+30 −13
Original line number Diff line number Diff line
@@ -1441,6 +1441,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) 
	return 0;



out:

	if (arg != F_UNLCK)

		locks_free_lock(lease);

	return error;

}
@@ -1493,17 +1494,16 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease) 
}

EXPORT_SYMBOL_GPL(vfs_setlease);



/**

 *	fcntl_setlease	-	sets a lease on an open file

 *	@fd: open file descriptor

 *	@filp: file pointer

 *	@arg: type of lease to obtain

 *

 *	Call this fcntl to establish a lease on the file.

 *	Note that you also need to call %F_SETSIG to

 *	receive a signal when the lease is broken.

 */

int fcntl_setlease(unsigned int fd, struct file *filp, long arg)

static int do_fcntl_delete_lease(struct file *filp)

{

	struct file_lock fl, *flp = &fl;



	lease_init(filp, F_UNLCK, flp);



	return vfs_setlease(filp, F_UNLCK, &flp);

}



static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)

{

	struct file_lock *fl;

	struct fasync_struct *new;
@@ -1521,7 +1521,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) 
	}

	lock_flocks();

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

	if (error || arg == F_UNLCK)

	if (error)

		goto out_unlock;



	/*
@@ -1549,6 +1549,23 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) 
	return error;

}



/**

 *	fcntl_setlease	-	sets a lease on an open file

 *	@fd: open file descriptor

 *	@filp: file pointer

 *	@arg: type of lease to obtain

 *

 *	Call this fcntl to establish a lease on the file.

 *	Note that you also need to call %F_SETSIG to

 *	receive a signal when the lease is broken.

 */

int fcntl_setlease(unsigned int fd, struct file *filp, long arg)

{

	if (arg == F_UNLCK)

		return do_fcntl_delete_lease(filp);

	return do_fcntl_add_lease(fd, filp, arg);

}



/**

 * flock_lock_file_wait - Apply a FLOCK-style lock to a file

 * @filp: The file to apply the lock to