nfs: store devname at disconnected NFS roots

part 2: make sure that disconnected roots have corresponding mnt_devname
values stashed into them.

Have nfs*_get_root() stuff a copy of devname into ->d_fsdata of the
found root, provided that it is disconnected.

Have ->d_release() free it when dentry goes away.

Have the places where NFS uses ->d_fsdata for sillyrename (and that
can *never* happen to a disconnected root - dentry will be attached
to its parent) free old devname copies if they find those.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 32 insertions, 4 deletions

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index 4d6e5a317e6d..1084792bc0fe 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -82,12 +82,18 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
         struct nfs_fsinfo fsinfo;
         struct dentry *ret;
         struct inode *inode;
+        void *name = kstrdup(devname, GFP_KERNEL);
         int error;
 
+        if (!name)
+                return ERR_PTR(-ENOMEM);
+
         /* get the actual root for this mount */
         fsinfo.fattr = nfs_alloc_fattr();
-        if (fsinfo.fattr == NULL)
+        if (fsinfo.fattr == NULL) {
+                kfree(name);
                 return ERR_PTR(-ENOMEM);
+        }
 
         error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
         if (error < 0) {
@@ -120,7 +126,15 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
         }
 
         security_d_instantiate(ret, inode);
+        spin_lock(&ret->d_lock);
+        if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
+                ret->d_fsdata = name;
+                name = NULL;
+        }
+        spin_unlock(&ret->d_lock);
 out:
+        if (name)
+                kfree(name);
         nfs_free_fattr(fsinfo.fattr);
         return ret;
 }
@@ -177,21 +191,28 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
         struct nfs_fattr *fattr = NULL;
         struct dentry *ret;
         struct inode *inode;
+        void *name = kstrdup(devname, GFP_KERNEL);
         int error;
 
         dprintk("--> nfs4_get_root()\n");
 
+        if (!name)
+                return ERR_PTR(-ENOMEM);
+
         /* get the info about the server and filesystem */
         error = nfs4_server_capabilities(server, mntfh);
         if (error < 0) {
                 dprintk("nfs_get_root: getcaps error = %d\n",
                         -error);
+                kfree(name);
                 return ERR_PTR(error);
         }
 
         fattr = nfs_alloc_fattr();
-        if (fattr == NULL)
-                return ERR_PTR(-ENOMEM);;
+        if (fattr == NULL) {
+                kfree(name);
+                return ERR_PTR(-ENOMEM);
+        }
 
         /* get the actual root for this mount */
         error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
@@ -225,8 +246,15 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
         }
 
         security_d_instantiate(ret, inode);
-
+        spin_lock(&ret->d_lock);
+        if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
+                ret->d_fsdata = name;
+                name = NULL;
+        }
+        spin_unlock(&ret->d_lock);
 out:
+        if (name)
+                kfree(name);
         nfs_free_fattr(fattr);
         dprintk("<-- nfs4_get_root()\n");
         return ret;