(WIP) smb: client: attemp to fix case-sensitivity issues with DFS pathsfix-paths-case

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>

1 files changed, 130 insertions, 2 deletions

diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
index 9bfc0a592d27..f0534c7ff5c4 100644
--- a/fs/smb/client/namespace.c
+++ b/fs/smb/client/namespace.c
@@ -183,10 +183,115 @@ static void fs_context_set_ids(struct smb3_fs_context *ctx)
 		ctx->cred_uid = uid;
 }
 
+#include "../../mount.h"
+
+static inline char *get_d_fullpath(struct dentry *d)
+{
+	struct dentry *cur;
+	struct list_head ld = LIST_HEAD_INIT(ld);
+	struct {
+		struct list_head l;
+		struct dentry *e;
+	} dl[32] = { 0 }, *dlp;
+	char *path;
+	size_t len = 0, n = 0;
+
+	cur = d;
+	while (cur) {
+		if (!strncmp(cur->d_name.name, "/", 1))
+			break;
+
+		dl[n].e = cur;
+		INIT_LIST_HEAD(&dl[n].l);
+		list_add(&dl[n].l, &ld);
+
+		n++;
+		len += cur->d_name.len;
+		cur = cur->d_parent;
+	}
+
+	if (len == 0 || n == 0)
+		return kstrdup("/", GFP_KERNEL);
+
+	path = kzalloc(len + n + 1, GFP_KERNEL);
+	if (!path)
+		return NULL;
+
+	/* reuse @n */
+	n = 0;
+
+	list_for_each_entry(dlp, &ld, l) {
+		len = dlp->e->d_name.len;
+		path[n++] = '/';
+
+		memcpy(&path[n], dlp->e->d_name.name, len);
+		n += len;
+	}
+
+	return path;
+}
+
+static inline struct vfsmount *find_existing_mnt(struct dentry *new, const char *src)
+{
+	struct super_block *sb = new->d_sb;
+	struct mount *m, *subm;
+	char *newp = get_d_fullpath(new);
+	//int p = 0;
+
+	//pr_err("%s: finding existing mount for (%s @ %s)\n", __func__, src, newp);
+
+	m = list_first_entry_or_null(&sb->s_mounts, struct mount, mnt_instance);
+	if (!m || list_empty(&m->mnt_mounts))
+		return NULL;
+
+#if 0
+	mp = get_d_fullpath(m->mnt_mountpoint);
+	pr_err("%s: mount #%d (%p): mpt=%s (raw=%pd), dev=%s\n",
+	       __func__, p, m, mp, m->mnt_mountpoint, m->mnt_devname);
+	kfree(mp);
+#endif
+
+	list_for_each_entry(subm, &m->mnt_mounts, mnt_child) {
+		char *oldp = get_d_fullpath(subm->mnt_mountpoint);
+		int len = strlen(oldp);
+
+		len = umin(len, strlen(newp));
+		//pr_err("%s: submount #%d (%p): mpt=%s (raw=%pd), dev=%s, matches=%d (oldp=%s == newp=%s)\n",
+		//       __func__, p, subm, oldp, subm->mnt_mountpoint, subm->mnt_devname, !strncasecmp(oldp, newp, len), oldp, newp);
+		//p++;
+
+		if (!strncasecmp(oldp, newp, len)) {
+			len = strlen(src);
+			len = umin(len, strlen(subm->mnt_devname));
+
+			if (!strncasecmp(src, subm->mnt_devname, len)) {
+				pr_err("%s: Found existing VFS mount for %s @ %p\n", __func__, newp, &m->mnt);
+				kfree(oldp);
+				kfree(newp);
+
+				return &m->mnt;
+			}
+		}
+
+#if 0
+		pr_err("%s: submount #%d (%p): mpt=%s, dev=%s, matches=%d\n",
+		       __func__, c, subm, oldp, subm->mnt_devname, !strncasecmp(oldp, newp, len));
+
+		//pr_err("%s: submount #%d (%p): mpt=%s, dev=%s, vfs=%p, sb=%p, has_children=%d, id=%d, parent=%p, matches=%d\n",
+		//       __func__, c, subm, oldp, subm->mnt_devname, &subm->mnt, subm->mnt.mnt_sb, !list_empty(&subm->mnt_mounts), subm->mnt_id, subm->mnt_parent, !strncasecmp(oldp, newp, len));
+#endif
+		kfree(oldp);
+	}
+
+	kfree(newp);
+
+	return NULL;
+}
+
 /*
  * Create a vfsmount that we can automount
  */
-static struct vfsmount *cifs_do_automount(struct path *path)
+static struct vfsmount *cifs_do_automount(struct path *path, bool *exist)
 {
 	int rc;
 	struct dentry *mntpt = path->dentry;
@@ -245,7 +350,26 @@ static struct vfsmount *cifs_do_automount(struct path *path)
 	cifs_dbg(FYI, "%s: ctx: source=%s UNC=%s prepath=%s dfs_automount=%d\n",
 		 __func__, ctx->source, ctx->UNC, ctx->prepath, ctx->dfs_conn);
 
+	//(void)find_existing_mnt(mntpt->d_sb->s_root, mntpt);
+	mnt = find_existing_mnt(mntpt, ctx->source);
+	if (mnt) {
+		pr_err("%s: mnt d flags %d, path d flags %d\n", __func__, !!(mnt->mnt_root->d_flags & DCACHE_NEED_AUTOMOUNT), !!(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT));
+		*exist = true;
+		//mntget(mnt);
+		goto out;
+	}
+
+	if (!fc->source) {
+		fc->source = kstrndup(ctx->source, strlen(ctx->source), GFP_KERNEL);
+		if (!fc->source) {
+			mnt = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+	}
+
 	mnt = fc_mount(fc);
+	//if (!IS_ERR(mnt))
+		//pr_err("%s: adding mount dev %s\n", __func__, container_of(mnt, struct mount, mnt)->mnt_devname);
 out:
 	put_fs_context(fc);
 	free_dentry_path(page);
@@ -258,15 +382,19 @@ out:
 struct vfsmount *cifs_d_automount(struct path *path)
 {
 	struct vfsmount *newmnt;
+	bool exist = false;
 
 	cifs_dbg(FYI, "%s: %pd\n", __func__, path->dentry);
 
-	newmnt = cifs_do_automount(path);
+	newmnt = cifs_do_automount(path, &exist);
 	if (IS_ERR(newmnt)) {
 		cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__);
 		return newmnt;
 	}
 
+	if (exist)
+		return NULL;
+
 	mntget(newmnt); /* prevent immediate expiration */
 	mnt_set_expiry(newmnt, &cifs_automount_list);
 	schedule_delayed_work(&cifs_automount_task,