linux-kernel - [PATCH 2/2] fsnotify: refactor mask filtering in send_to

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Date:	Sun, 29 Aug 2010 00:55:42 +0530
From:	Csaba Henk <csaba@...ster.com>
To:	linux-kernel@...r.kernel.org
Cc:	Eric Paris <eparis@...hat.com>, Csaba Henk <csaba@...ster.com>
Subject: [PATCH 2/2] fsnotify: refactor mask filtering in send_to_group()

- isolate filtering logic to reduce code duplication
- the case when only one mark is passed was not handled correctly:
  in this case the mask variable for the other mark was not
  filtered, giving therefore a green way, regardless the mask of
  the mark which was actually there to be tested

Signed-off-by: Csaba Henk <csaba@...ster.com>
---
 fs/notify/fsnotify.c |   44 +++++++++++++++++---------------------------
 1 files changed, 17 insertions(+), 27 deletions(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 6657315..ece4bd6 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -140,6 +140,20 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 
+static int check_mark_mask(struct fsnotify_mark *mark, __u32 *mask)
+{
+	if (!mark)
+		return 0;
+
+	if ((*mask & FS_MODIFY) &&
+	    !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
+		mark->ignored_mask = 0;
+	else
+		*mask &= ~mark->ignored_mask;
+
+	return *mask & mark->mask;
+}
+
 static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
 			 struct fsnotify_mark *inode_mark,
 			 struct fsnotify_mark *vfsmount_mark,
@@ -149,8 +163,7 @@ static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
 			 struct fsnotify_event **event)
 {
 	struct fsnotify_group *group;
-	__u32 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
-	__u32 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
+	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
 
 	if (inode_mark)
 		group = inode_mark->group;
@@ -164,31 +177,8 @@ static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
 		 __func__, group, to_tell, mnt, inode_mark, vfsmount_mark, mask,
 		 data, data_is, cookie, *event);
 
-	/* clear ignored on inode modification */
-	if (mask & FS_MODIFY) {
-		if (inode_mark &&
-		    !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
-			inode_mark->ignored_mask = 0;
-		if (vfsmount_mark &&
-		    !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
-			vfsmount_mark->ignored_mask = 0;
-	}
-
-	/* does the inode mark tell us to do something? */
-	if (inode_mark) {
-		inode_test_mask &= inode_mark->mask;
-		inode_test_mask &= ~inode_mark->ignored_mask;
-	}
-
-	/* does the vfsmount_mark tell us to do something? */
-	if (vfsmount_mark) {
-		vfsmount_test_mask &= vfsmount_mark->mask;
-		vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
-		if (inode_mark)
-			vfsmount_test_mask &= ~inode_mark->ignored_mask;
-	}
-
-	if (!inode_test_mask && !vfsmount_test_mask)
+	if (!(check_mark_mask(inode_mark, &test_mask) ||
+	      check_mark_mask(vfsmount_mark, &test_mask)))
 		return 0;
 
 	if (group->ops->should_send_event(group, to_tell, inode_mark,
-- 
1.7.2.2

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