6.6-stable review patch. If anyone has any objections, please let me know.
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From: Hongbo Li lihongbo22@huawei.com
commit ef9ca17ca458ac7253ae71b552e601e49311fc48 upstream.
hostfs not keep the host directory when mounting. When the host directory is none (default), fc->source is used as the host root directory, and this is wrong. Here we use `parse_monolithic` to handle the old mount path for parsing the root directory. For new mount path, The `parse_param` is used for the host directory parse.
Reported-and-tested-by: Maciej Żenczykowski maze@google.com Fixes: cd140ce9f611 ("hostfs: convert hostfs to use the new mount API") Link: https://lore.kernel.org/all/CANP3RGceNzwdb7w=vPf5=7BCid5HVQDmz1K5kC9JG42+HVA... Cc: Christian Brauner brauner@kernel.org Signed-off-by: Hongbo Li lihongbo22@huawei.com Link: https://lore.kernel.org/r/20240725065130.1821964-1-lihongbo22@huawei.com [brauner: minor fixes] Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/hostfs/hostfs_kern.c | 65 ++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 55 insertions(+), 10 deletions(-)
--- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -17,6 +17,7 @@ #include <linux/writeback.h> #include <linux/mount.h> #include <linux/fs_context.h> +#include <linux/fs_parser.h> #include <linux/namei.h> #include "hostfs.h" #include <init.h> @@ -925,7 +926,6 @@ static const struct inode_operations hos static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc) { struct hostfs_fs_info *fsi = sb->s_fs_info; - const char *host_root = fc->source; struct inode *root_inode; int err;
@@ -939,15 +939,6 @@ static int hostfs_fill_super(struct supe if (err) return err;
- /* NULL is printed as '(null)' by printf(): avoid that. */ - if (fc->source == NULL) - host_root = ""; - - fsi->host_root_path = - kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root); - if (fsi->host_root_path == NULL) - return -ENOMEM; - root_inode = hostfs_iget(sb, fsi->host_root_path); if (IS_ERR(root_inode)) return PTR_ERR(root_inode); @@ -973,6 +964,58 @@ static int hostfs_fill_super(struct supe return 0; }
+enum hostfs_parma { + Opt_hostfs, +}; + +static const struct fs_parameter_spec hostfs_param_specs[] = { + fsparam_string_empty("hostfs", Opt_hostfs), + {} +}; + +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; + int opt; + + opt = fs_parse(fc, hostfs_param_specs, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + 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) + return -ENOMEM; + break; + } + + return 0; +} + +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; + + /* NULL is printed as '(null)' by printf(): avoid that. */ + if (host_root == NULL) + host_root = ""; + + fsi->host_root_path = + kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root); + if (fsi->host_root_path == NULL) + return -ENOMEM; + + return 0; +} + static int hostfs_fc_get_tree(struct fs_context *fc) { return get_tree_nodev(fc, hostfs_fill_super); @@ -990,6 +1033,8 @@ static void hostfs_fc_free(struct fs_con }
static const struct fs_context_operations hostfs_context_ops = { + .parse_monolithic = hostfs_parse_monolithic, + .parse_param = hostfs_parse_param, .get_tree = hostfs_fc_get_tree, .free = hostfs_fc_free, };