fs: scale inode alias list

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@kernel.dk>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index aa4f25e803f6..ae769fc9b66c 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -60,6 +60,7 @@ 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) {
@@ -82,6 +83,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
                 }
                 spin_unlock(&alias->d_lock);
         }
+        spin_unlock(&dcache_inode_lock);
         spin_unlock(&dcache_lock);
 }