6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hongbo Li <lihongbo22@xxxxxxxxxx>
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@xxxxxxxxxx>
Fixes: cd140ce9f611 ("hostfs: convert hostfs to use the new mount API")
Link: https://lore.kernel.org/all/CANP3RGceNzwdb7w=vPf5=7BCid5HVQDmz1K5kC9JG42+HVAh_g@xxxxxxxxxxxxxx/
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Hongbo Li <lihongbo22@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240725065130.1821964-1-lihongbo22@xxxxxxxxxx
[brauner: minor fixes]
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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,
};
