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, 4 insertions, 0 deletions

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index ac7b814ce162..850f67d5f0ac 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -64,7 +64,11 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
                  * Oops, since the test for IS_ROOT() will fail.
                  */
                 spin_lock(&dcache_lock);
+                spin_lock(&dcache_inode_lock);
+                spin_lock(&sb->s_root->d_lock);
                 list_del_init(&sb->s_root->d_alias);
+                spin_unlock(&sb->s_root->d_lock);
+                spin_unlock(&dcache_inode_lock);
                 spin_unlock(&dcache_lock);
         }
         return 0;