Unverified Commit 3781680f authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "pidfs: support bind-mounts" 

Christian Brauner <brauner@kernel.org> says:

Allow bind-mounting pidfds. Similar to nsfs let's allow bind-mounts for
pidfds. This allows pidfds to be safely recovered and checked for
process recycling.

Instead of checking d_ops for both nsfs and pidfs we could in a
follow-up patch add a flag argument to struct dentry_operations that
functions similar to file_operations->fop_flags.

* patches from https://lore.kernel.org/r/20241219-work-pidfs-mount-v1-0-dbc56198b839@kernel.org:
  selftests: add pidfd bind-mount tests
  pidfs: allow bind-mounts

Link: https://lore.kernel.org/r/20241219-work-pidfs-mount-v1-0-dbc56198b839@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 16ecd47c f63df616

fs/namespace.c

+8 −2
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <linux/fs_context.h>

#include <linux/shmem_fs.h>

#include <linux/mnt_idmapping.h>

#include <linux/pidfs.h>

#include <linux/nospec.h>



#include "pnode.h"
@@ -2732,8 +2733,13 @@ static struct mount *__do_loopback(struct path *old_path, int recurse) 
	if (IS_MNT_UNBINDABLE(old))

		return mnt;



	if (!check_mnt(old) && old_path->dentry->d_op != &ns_dentry_operations)

	if (!check_mnt(old)) {

		const struct dentry_operations *d_op = old_path->dentry->d_op;



		if (d_op != &ns_dentry_operations &&

		    d_op != &pidfs_dentry_operations)

			return mnt;

	}



	if (!recurse && has_locked_children(old, old_path->dentry))

		return mnt;

fs/pidfs.c

+1 −1
Original line number Diff line number Diff line
@@ -510,7 +510,7 @@ static char *pidfs_dname(struct dentry *dentry, char *buffer, int buflen) 
	return dynamic_dname(buffer, buflen, "anon_inode:[pidfd]");

}



static const struct dentry_operations pidfs_dentry_operations = {

const struct dentry_operations pidfs_dentry_operations = {

	.d_delete	= always_delete_dentry,

	.d_dname	= pidfs_dname,

	.d_prune	= stashed_dentry_prune,

include/linux/pidfs.h

+1 −0
Original line number Diff line number Diff line
@@ -6,5 +6,6 @@ struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags); 
void __init pidfs_init(void);

void pidfs_add_pid(struct pid *pid);

void pidfs_remove_pid(struct pid *pid);

extern const struct dentry_operations pidfs_dentry_operations;



#endif /* _LINUX_PID_FS_H */

tools/testing/selftests/pidfd/.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -7,3 +7,4 @@ pidfd_fdinfo_test 
pidfd_getfd_test

pidfd_setns_test

pidfd_file_handle_test

pidfd_bind_mount

tools/testing/selftests/pidfd/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ CFLAGS += -g $(KHDR_INCLUDES) -pthread -Wall 


TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \

	pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test \

	pidfd_file_handle_test

	pidfd_file_handle_test pidfd_bind_mount



include ../lib.mk