From 2c2b67af5f5f77fc68261a137ad65dcfb8e52506 Mon Sep 17 00:00:00 2001 From: Hongbo Li Date: Sat, 11 Oct 2025 09:22:35 +0000 Subject: [PATCH] hostfs: Fix only passing host root in boot stage with new mount In the old mount proceedure, hostfs could only pass root directory during boot. This is because it constructed the root directory using the @root_ino event without any mount options. However, when using it with the new mount API, this step is no longer triggered. As a result, if users mounts without specifying any mount options, the @host_root_path remains uninitialized. To prevent this issue, the @host_root_path should be initialized at the time of allocation. Reported-by: Geoffrey Thorpe Closes: https://lore.kernel.org/all/643333a0-f434-42fb-82ac-d25a0b56f3b7@geoffthorpe.net/ Fixes: cd140ce9f611 ("hostfs: convert hostfs to use the new mount API") Signed-off-by: Hongbo Li Link: https://patch.msgid.link/20251011092235.29880-1-lihongbo22@huawei.com Signed-off-by: Christian Brauner --- fs/hostfs/hostfs_kern.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 1e1acf5775ab5..86455eebbf6cf 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -979,7 +979,7 @@ static int hostfs_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct hostfs_fs_info *fsi = fc->s_fs_info; struct fs_parse_result result; - char *host_root; + char *host_root, *tmp_root; int opt; opt = fs_parse(fc, hostfs_param_specs, param, &result); @@ -990,11 +990,13 @@ static int hostfs_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_hostfs: host_root = param->string; if (!*host_root) - host_root = ""; - fsi->host_root_path = - kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root); - if (fsi->host_root_path == NULL) + break; + tmp_root = kasprintf(GFP_KERNEL, "%s%s", + fsi->host_root_path, host_root); + if (!tmp_root) return -ENOMEM; + kfree(fsi->host_root_path); + fsi->host_root_path = tmp_root; break; } @@ -1004,17 +1006,17 @@ static int hostfs_parse_param(struct fs_context *fc, struct fs_parameter *param) static int hostfs_parse_monolithic(struct fs_context *fc, void *data) { struct hostfs_fs_info *fsi = fc->s_fs_info; - char *host_root = (char *)data; + char *tmp_root, *host_root = (char *)data; /* NULL is printed as '(null)' by printf(): avoid that. */ if (host_root == NULL) - host_root = ""; + return 0; - fsi->host_root_path = - kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root); - if (fsi->host_root_path == NULL) + tmp_root = kasprintf(GFP_KERNEL, "%s%s", fsi->host_root_path, host_root); + if (!tmp_root) return -ENOMEM; - + kfree(fsi->host_root_path); + fsi->host_root_path = tmp_root; return 0; } @@ -1049,6 +1051,11 @@ static int hostfs_init_fs_context(struct fs_context *fc) if (!fsi) return -ENOMEM; + fsi->host_root_path = kasprintf(GFP_KERNEL, "%s/", root_ino); + if (!fsi->host_root_path) { + kfree(fsi); + return -ENOMEM; + } fc->s_fs_info = fsi; fc->ops = &hostfs_context_ops; return 0; -- 2.47.3