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, 3 insertions, 0 deletions

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 589f3e3f6e00..003698365ece 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -810,12 +810,15 @@ inode_has_hashed_dentries(struct inode *inode)
         struct dentry *dentry;
 
         spin_lock(&dcache_lock);
+        spin_lock(&dcache_inode_lock);
         list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
                 if (!d_unhashed(dentry) || IS_ROOT(dentry)) {
+                        spin_unlock(&dcache_inode_lock);
                         spin_unlock(&dcache_lock);
                         return true;
                 }
         }
+        spin_unlock(&dcache_inode_lock);
         spin_unlock(&dcache_lock);
         return false;
 }