fs-dcache-scale-i_dentry

Add a new lock, dcache_inode_lock, to protect the inode's i_dentry list
from concurrent modification. d_alias is also protected by d_lock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 4 insertions, 0 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 03ee7430867d..709dae31b03b 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -53,6 +53,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 	watched = fsnotify_inode_watches_children(inode);
 
 	spin_lock(&dcache_lock);
+	spin_lock(&dcache_inode_lock);
 	/* run all of the dentries associated with this inode.  Since this is a
 	 * directory, there damn well better only be one item on this list */
 	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
@@ -75,6 +76,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 		}
 		spin_unlock(&alias->d_lock);
 	}
+	spin_unlock(&dcache_inode_lock);
 	spin_unlock(&dcache_lock);
 }
 
diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c
index a838e58e6e4a..977d3f6f79e1 100644
--- a/fs/notify/inotify/inotify.c
+++ b/fs/notify/inotify/inotify.c
@@ -186,6 +186,7 @@ static void set_dentry_child_flags(struct inode *inode, int watched)
 	struct dentry *alias;
 
 	spin_lock(&dcache_lock);
+	spin_lock(&dcache_inode_lock);
 	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
 		struct dentry *child;
 
@@ -203,6 +204,7 @@ static void set_dentry_child_flags(struct inode *inode, int watched)
 		}
 		spin_unlock(&alias->d_lock);
 	}
+	spin_unlock(&dcache_inode_lock);
 	spin_unlock(&dcache_lock);
 }