[Devel] [PATCH rh7] fuse: allow to mount fuse filesystems inside CT

[Andrey Ryabinin]

Currently mounting fuse fs inside CT fails because
we don't pass (file->f_cred->user_ns != &init_user_ns) check.
Test file's namespace against VE's init_cred->user_ns instead.
This allows to use fuse inside containers.

https://jira.sw.ru/browse/PSBM-41075

Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 fs/fuse/inode.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 4a1b46f..d7e2d4b 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -20,6 +20,7 @@
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/exportfs.h>
+#include <linux/ve.h>
 
 MODULE_AUTHOR("Miklos Szeredi <miklos at szeredi.hu>");
 MODULE_DESCRIPTION("Filesystem in Userspace");
@@ -1115,6 +1116,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	struct fuse_req *init_req;
 	int err;
 	int is_bdev = sb->s_bdev != NULL;
+	struct user_namespace *root_user_ns;
 
 	err = -EINVAL;
 	if (sb->s_flags & MS_MANDLOCK)
@@ -1146,8 +1148,13 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (!file)
 		goto err;
 
+	if (get_exec_env()->init_cred)
+		root_user_ns = get_exec_env()->init_cred->user_ns;
+	else
+		root_user_ns = &init_user_ns;
+
 	if ((file->f_op != &fuse_dev_operations) ||
-	    (file->f_cred->user_ns != &init_user_ns))
+	    (file->f_cred->user_ns != root_user_ns))
 		goto err_fput;
 
 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
-- 
2.4.10