File locking related fixes for v3.20 (pile #2)

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Merge tag 'locks-v3.20-2' of git://git.samba.org/jlayton/linux

Pull file locking fixes from Jeff Layton:
 "A small set of patches to fix problems with the recent file locking
  changes that we discussed earlier this week"
"

* tag 'locks-v3.20-2' of git://git.samba.org/jlayton/linux:
  locks: fix list insertion when lock is split in two
  locks: remove conditional lock release in middle of flock_lock_file
  locks: only remove leases associated with the file being closed
  Revert "locks: keep a count of locks on the flctx lists"

fs/ceph/locks.c

@@ -245,6 +245,7 @@ int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
  */
 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 {
+	struct file_lock *lock;
 	struct file_lock_context *ctx;
 
 	*fcntl_count = 0;
@@ -252,8 +253,12 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
 
 	ctx = inode->i_flctx;
 	if (ctx) {
-		*fcntl_count = ctx->flc_posix_cnt;
-		*flock_count = ctx->flc_flock_cnt;
+		spin_lock(&ctx->flc_lock);
+		list_for_each_entry(lock, &ctx->flc_posix, fl_list)
+			++(*fcntl_count);
+		list_for_each_entry(lock, &ctx->flc_flock, fl_list)
+			++(*flock_count);
+		spin_unlock(&ctx->flc_lock);
 	}
 	dout("counted %d flock locks and %d fcntl locks",
 	     *flock_count, *fcntl_count);

fs/cifs/file.c

@@ -1129,7 +1129,7 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	struct file_lock *flock;
 	struct file_lock_context *flctx = inode->i_flctx;
-	unsigned int i;
+	unsigned int count = 0, i;
 	int rc = 0, xid, type;
 	struct list_head locks_to_send, *el;
 	struct lock_to_push *lck, *tmp;
@@ -1140,14 +1140,20 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
 	if (!flctx)
 		goto out;
 
+	spin_lock(&flctx->flc_lock);
+	list_for_each(el, &flctx->flc_posix) {
+		count++;
+	}
+	spin_unlock(&flctx->flc_lock);
+
 	INIT_LIST_HEAD(&locks_to_send);
 
 	/*
-	 * Allocating flc_posix_cnt locks is enough because no FL_POSIX locks
-	 * can be added to the list while we are holding cinode->lock_sem that
+	 * Allocating count locks is enough because no FL_POSIX locks can be
+	 * added to the list while we are holding cinode->lock_sem that
 	 * protects locking operations of this inode.
 	 */
-	for (i = 0; i < flctx->flc_posix_cnt; i++) {
+	for (i = 0; i < count; i++) {
 		lck = kmalloc(sizeof(struct lock_to_push), GFP_KERNEL);
 		if (!lck) {
 			rc = -ENOMEM;

fs/locks.c

@@ -681,21 +681,18 @@ static void locks_wake_up_blocks(struct file_lock *blocker)
 }
 
 static void
-locks_insert_lock_ctx(struct file_lock *fl, int *counter,
-		      struct list_head *before)
+locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
 {
 	fl->fl_nspid = get_pid(task_tgid(current));
 	list_add_tail(&fl->fl_list, before);
-	++*counter;
 	locks_insert_global_locks(fl);
 }
 
 static void
-locks_unlink_lock_ctx(struct file_lock *fl, int *counter)
+locks_unlink_lock_ctx(struct file_lock *fl)
 {
 	locks_delete_global_locks(fl);
 	list_del_init(&fl->fl_list);
-	--*counter;
 	if (fl->fl_nspid) {
 		put_pid(fl->fl_nspid);
 		fl->fl_nspid = NULL;
@@ -704,10 +701,9 @@ locks_unlink_lock_ctx(struct file_lock *fl, int *counter)
 }
 
 static void
-locks_delete_lock_ctx(struct file_lock *fl, int *counter,
-		      struct list_head *dispose)
+locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
 {
-	locks_unlink_lock_ctx(fl, counter);
+	locks_unlink_lock_ctx(fl);
 	if (dispose)
 		list_add(&fl->fl_list, dispose);
 	else
@@ -895,7 +891,7 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
 		if (request->fl_type == fl->fl_type)
 			goto out;
 		found = true;
-		locks_delete_lock_ctx(fl, &ctx->flc_flock_cnt, &dispose);
+		locks_delete_lock_ctx(fl, &dispose);
 		break;
 	}
 
@@ -905,16 +901,6 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
 		goto out;
 	}
 
-	/*
-	 * If a higher-priority process was blocked on the old file lock,
-	 * give it the opportunity to lock the file.
-	 */
-	if (found) {
-		spin_unlock(&ctx->flc_lock);
-		cond_resched();
-		spin_lock(&ctx->flc_lock);
-	}
-
 find_conflict:
 	list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
 		if (!flock_locks_conflict(request, fl))
@@ -929,7 +915,7 @@ find_conflict:
 	if (request->fl_flags & FL_ACCESS)
 		goto out;
 	locks_copy_lock(new_fl, request);
-	locks_insert_lock_ctx(new_fl, &ctx->flc_flock_cnt, &ctx->flc_flock);
+	locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
 	new_fl = NULL;
 	error = 0;
 
@@ -1046,8 +1032,7 @@ 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_ctx(fl, &ctx->flc_posix_cnt,
-							&dispose);
+				locks_delete_lock_ctx(fl, &dispose);
 				continue;
 			}
 			request = fl;
@@ -1076,8 +1061,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 				 * one (This may happen several times).
 				 */
 				if (added) {
-					locks_delete_lock_ctx(fl,
-						&ctx->flc_posix_cnt, &dispose);
+					locks_delete_lock_ctx(fl, &dispose);
 					continue;
 				}
 				/*
@@ -1093,10 +1077,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 				locks_copy_lock(new_fl, request);
 				request = new_fl;
 				new_fl = NULL;
-				locks_insert_lock_ctx(request,
-					&ctx->flc_posix_cnt, &fl->fl_list);
-				locks_delete_lock_ctx(fl,
-					&ctx->flc_posix_cnt, &dispose);
+				locks_insert_lock_ctx(request, &fl->fl_list);
+				locks_delete_lock_ctx(fl, &dispose);
 				added = true;
 			}
 		}
@@ -1124,8 +1106,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 			goto out;
 		}
 		locks_copy_lock(new_fl, request);
-		locks_insert_lock_ctx(new_fl, &ctx->flc_posix_cnt,
-					&fl->fl_list);
+		locks_insert_lock_ctx(new_fl, &fl->fl_list);
+		fl = new_fl;
 		new_fl = NULL;
 	}
 	if (right) {
@@ -1136,8 +1118,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 			left = new_fl2;
 			new_fl2 = NULL;
 			locks_copy_lock(left, right);
-			locks_insert_lock_ctx(left, &ctx->flc_posix_cnt,
-						&fl->fl_list);
+			locks_insert_lock_ctx(left, &fl->fl_list);
 		}
 		right->fl_start = request->fl_end + 1;
 		locks_wake_up_blocks(right);
@@ -1321,7 +1302,6 @@ 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 *fl, int arg, struct list_head *dispose)
 {
-	struct file_lock_context *flctx;
 	int error = assign_type(fl, arg);
 
 	if (error)
@@ -1331,7 +1311,6 @@ int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
 	if (arg == F_UNLCK) {
 		struct file *filp = fl->fl_file;
 
-		flctx = file_inode(filp)->i_flctx;
 		f_delown(filp);
 		filp->f_owner.signum = 0;
 		fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
@@ -1339,7 +1318,7 @@ int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
 			printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
 			fl->fl_fasync = NULL;
 		}
-		locks_delete_lock_ctx(fl, &flctx->flc_lease_cnt, dispose);
+		locks_delete_lock_ctx(fl, dispose);
 	}
 	return 0;
 }
@@ -1456,8 +1435,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 			fl->fl_downgrade_time = break_time;
 		}
 		if (fl->fl_lmops->lm_break(fl))
-			locks_delete_lock_ctx(fl, &ctx->flc_lease_cnt,
-						&dispose);
+			locks_delete_lock_ctx(fl, &dispose);
 	}
 
 	if (list_empty(&ctx->flc_lease))
@@ -1697,7 +1675,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
 	if (!leases_enable)
 		goto out;
 
-	locks_insert_lock_ctx(lease, &ctx->flc_lease_cnt, &ctx->flc_lease);
+	locks_insert_lock_ctx(lease, &ctx->flc_lease);
 	/*
 	 * The check in break_lease() is lockless. It's possible for another
 	 * open to race in after we did the earlier check for a conflicting
@@ -1710,7 +1688,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
 	smp_mb();
 	error = check_conflicting_open(dentry, arg, lease->fl_flags);
 	if (error) {
-		locks_unlink_lock_ctx(lease, &ctx->flc_lease_cnt);
+		locks_unlink_lock_ctx(lease);
 		goto out;
 	}
 
@@ -2448,7 +2426,8 @@ locks_remove_lease(struct file *filp)
 
 	spin_lock(&ctx->flc_lock);
 	list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
-		lease_modify(fl, F_UNLCK, &dispose);
+		if (filp == fl->fl_file)
+			lease_modify(fl, F_UNLCK, &dispose);
 	spin_unlock(&ctx->flc_lock);
 	locks_dispose_list(&dispose);
 }

include/linux/fs.h

@@ -968,9 +968,6 @@ struct file_lock_context {
 	struct list_head	flc_flock;
 	struct list_head	flc_posix;
 	struct list_head	flc_lease;
-	int			flc_flock_cnt;
-	int			flc_posix_cnt;
-	int			flc_lease_cnt;
 };
 
 /* The following constant reflects the upper bound of the file/locking space */