Merge tag 'vfs-6.14-rc7.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Bring in an RCU pathwalk fix for afs. This is brought in as a merge
   from the vfs-6.15.shared.afs branch that needs this commit and other
   trees already depend on it.

 - Fix vboxfs unterminated string handling.

* tag 'vfs-6.14-rc7.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs:
  vboxsf: Add __nonstring annotations for unterminated strings
  afs: Fix afs_atcell_get_link() to handle RCU pathwalk

5 files changed, 23 insertions, 12 deletions

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index cee42646736c..96a6781f3653 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -64,7 +64,8 @@ static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
 		return ERR_PTR(-ENAMETOOLONG);
 
 	if (!name) {
-		cell = net->ws_cell;
+		cell = rcu_dereference_protected(net->ws_cell,
+						 lockdep_is_held(&net->cells_lock));
 		if (!cell)
 			return ERR_PTR(-EDESTADDRREQ);
 		goto found;
@@ -388,8 +389,8 @@ int afs_cell_init(struct afs_net *net, const char *rootcell)
 	/* install the new cell */
 	down_write(&net->cells_lock);
 	afs_see_cell(new_root, afs_cell_trace_see_ws);
-	old_root = net->ws_cell;
-	net->ws_cell = new_root;
+	old_root = rcu_replace_pointer(net->ws_cell, new_root,
+				       lockdep_is_held(&net->cells_lock));
 	up_write(&net->cells_lock);
 
 	afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
@@ -945,8 +946,8 @@ void afs_cell_purge(struct afs_net *net)
 	_enter("");
 
 	down_write(&net->cells_lock);
-	ws = net->ws_cell;
-	net->ws_cell = NULL;
+	ws = rcu_replace_pointer(net->ws_cell, NULL,
+				 lockdep_is_held(&net->cells_lock));
 	up_write(&net->cells_lock);
 	afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);
 
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index d8bf52f77d93..008698d706ca 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -314,12 +314,23 @@ static const char *afs_atcell_get_link(struct dentry *dentry, struct inode *inod
 	const char *name;
 	bool dotted = vnode->fid.vnode == 3;
 
-	if (!net->ws_cell)
+	if (!dentry) {
+		/* We're in RCU-pathwalk. */
+		cell = rcu_dereference(net->ws_cell);
+		if (dotted)
+			name = cell->name - 1;
+		else
+			name = cell->name;
+		/* Shouldn't need to set a delayed call. */
+		return name;
+	}
+
+	if (!rcu_access_pointer(net->ws_cell))
 		return ERR_PTR(-ENOENT);
 
 	down_read(&net->cells_lock);
 
-	cell = net->ws_cell;
+	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
 	if (dotted)
 		name = cell->name - 1;
 	else
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 90f407774a9a..df30bd62da79 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -287,7 +287,7 @@ struct afs_net {
 
 	/* Cell database */
 	struct rb_root		cells;
-	struct afs_cell		*ws_cell;
+	struct afs_cell __rcu	*ws_cell;
 	struct work_struct	cells_manager;
 	struct timer_list	cells_timer;
 	atomic_t		cells_outstanding;
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index e7614f4f30c2..12c88d8be3fe 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -206,7 +206,7 @@ static int afs_proc_rootcell_show(struct seq_file *m, void *v)
 
 	net = afs_seq2net_single(m);
 	down_read(&net->cells_lock);
-	cell = net->ws_cell;
+	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
 	if (cell)
 		seq_printf(m, "%s\n", cell->name);
 	up_read(&net->cells_lock);
@@ -242,7 +242,7 @@ static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
 
 	ret = -EEXIST;
 	inode_lock(file_inode(file));
-	if (!net->ws_cell)
+	if (!rcu_access_pointer(net->ws_cell))
 		ret = afs_cell_init(net, buf);
 	else
 		printk("busy\n");
diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index 1d94bb784108..0bc96ab6580b 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -21,8 +21,7 @@
 
 #define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
 
-static const unsigned char VBSF_MOUNT_SIGNATURE[4] = { '\000', '\377', '\376',
-						       '\375' };
+static const unsigned char VBSF_MOUNT_SIGNATURE[4] __nonstring = "\000\377\376\375";
 
 static int follow_symlinks;
 module_param(follow_symlinks, int, 0444);