Unverified Commit accdd119 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge afs RCU pathwalk fix 



Bring in the fix for afs_atcell_get_link() to handle RCU pathwalk from
the afs branch for this cycle. This fix has to go upstream now.

Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 00a7d398 823869e1

fs/afs/cell.c

+6 −5
Original line number Diff line number Diff line
@@ -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);

fs/afs/dynroot.c

+13 −2
Original line number Diff line number Diff line
@@ -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

fs/afs/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

fs/afs/proc.c

+2 −2
Original line number Diff line number Diff line
@@ -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");