Commit a091d971 authored by Wang Zhaolong's avatar Wang Zhaolong Committed by Steve French
Browse files

smb:client: smb: client: Add reverse mapping from tcon to superblocks 



Currently, when a SMB connection is reset and renegotiated with the
server, there's no way to update all related mount points with new
negotiated sizes. This is because while superblocks (cifs_sb_info)
maintain references to tree connections (tcon) through tcon_link
structures, there is no reverse mapping from a tcon back to all the
superblocks using it.

This patch adds a bidirectional relationship between tcon and
cifs_sb_info structures by:

1. Adding a cifs_sb_list to tcon structure with appropriate locking
2. Adding tcon_sb_link to cifs_sb_info to join the list
3. Managing the list entries during mount and umount operations

The bidirectional relationship enables future functionality to locate and
update all superblocks connected to a specific tree connection, such as:

- Updating negotiated parameters after reconnection
- Efficiently notifying all affected mounts of capability changes

This is the first part of a series to improve connection resilience
by keeping all mount parameters in sync with server capabilities
after reconnection.

Signed-off-by: default avatarWang Zhaolong <wangzhaolong1@huawei.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent be5d361e

fs/smb/client/cifs_fs_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 


struct cifs_sb_info {

	struct rb_root tlink_tree;

	struct list_head tcon_sb_link;

	spinlock_t tlink_tree_lock;

	struct tcon_link *master_tlink;

	struct nls_table *local_nls;

fs/smb/client/cifsglob.h

+2 −1
Original line number Diff line number Diff line
@@ -1321,7 +1321,8 @@ struct cifs_tcon { 
#endif

	struct list_head pending_opens;	/* list of incomplete opens */

	struct cached_fids *cfids;

	/* BB add field for back pointer to sb struct(s)? */

	struct list_head cifs_sb_list;

	spinlock_t sb_list_lock;

#ifdef CONFIG_CIFS_DFS_UPCALL

	struct delayed_work dfs_cache_work;

	struct list_head dfs_ses_list;

fs/smb/client/connect.c

+15 −0
Original line number Diff line number Diff line
@@ -3477,6 +3477,7 @@ int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb) 
	struct smb3_fs_context *ctx = cifs_sb->ctx;



	INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);

	INIT_LIST_HEAD(&cifs_sb->tcon_sb_link);



	spin_lock_init(&cifs_sb->tlink_tree_lock);

	cifs_sb->tlink_tree = RB_ROOT;
@@ -3709,6 +3710,10 @@ static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses, 
	tlink_rb_insert(&cifs_sb->tlink_tree, tlink);

	spin_unlock(&cifs_sb->tlink_tree_lock);



	spin_lock(&tcon->sb_list_lock);

	list_add(&cifs_sb->tcon_sb_link, &tcon->cifs_sb_list);

	spin_unlock(&tcon->sb_list_lock);



	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,

				TLINK_IDLE_EXPIRE);

	return 0;
@@ -4050,9 +4055,19 @@ cifs_umount(struct cifs_sb_info *cifs_sb) 
	struct rb_root *root = &cifs_sb->tlink_tree;

	struct rb_node *node;

	struct tcon_link *tlink;

	struct cifs_tcon *tcon = NULL;



	cancel_delayed_work_sync(&cifs_sb->prune_tlinks);



	if (cifs_sb->master_tlink) {

		tcon = cifs_sb->master_tlink->tl_tcon;

		if (tcon) {

			spin_lock(&tcon->sb_list_lock);

			list_del_init(&cifs_sb->tcon_sb_link);

			spin_unlock(&tcon->sb_list_lock);

		}

	}



	spin_lock(&cifs_sb->tlink_tree_lock);

	while ((node = rb_first(root))) {

		tlink = rb_entry(node, struct tcon_link, tl_rbnode);

fs/smb/client/misc.c

+2 −0
Original line number Diff line number Diff line
@@ -137,8 +137,10 @@ tcon_info_alloc(bool dir_leases_enabled, enum smb3_tcon_ref_trace trace) 
	spin_lock_init(&ret_buf->tc_lock);

	INIT_LIST_HEAD(&ret_buf->openFileList);

	INIT_LIST_HEAD(&ret_buf->tcon_list);

	INIT_LIST_HEAD(&ret_buf->cifs_sb_list);

	spin_lock_init(&ret_buf->open_file_lock);

	spin_lock_init(&ret_buf->stat_lock);

	spin_lock_init(&ret_buf->sb_list_lock);

	atomic_set(&ret_buf->num_local_opens, 0);

	atomic_set(&ret_buf->num_remote_opens, 0);

	ret_buf->stats_from_time = ktime_get_real_seconds();