[PATCH 01/11] kernfs: implement i_generation
From: Shaohua Li <shli@kernel.org>
Date: 2017-06-02 21:56:50
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), kernfs, the rest · Maintainers:
Alexander Viro, Christian Brauner, Greg Kroah-Hartman, Tejun Heo, Linus Torvalds
From: Shaohua Li <redacted> Set i_generation for kernfs inode. This is required to implement exportfs operations. Note, the generation is 32-bit, so it's possible the generation wraps up and we find stale files. The possiblity is low, since fhandle matches both inode number and generation. In most fs, the generation is 32-bit. fhandle only export 32-bit generation for most fs. So unless we have solid reason, we'd live with the possible conflict. Signed-off-by: Shaohua Li <redacted> --- fs/kernfs/dir.c | 2 ++ fs/kernfs/inode.c | 1 + include/linux/kernfs.h | 2 ++ 3 files changed, 5 insertions(+)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index db5900aaa..09d093e 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c@@ -634,6 +634,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, if (ret < 0) goto err_out2; kn->ino = ret; + kn->generation = atomic_inc_return(&root->next_generation); atomic_set(&kn->count, 1); atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
@@ -877,6 +878,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, ida_init(&root->ino_ida); INIT_LIST_HEAD(&root->supers); + atomic_set(&root->next_generation, 0); kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR);
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index fb4b4a7..79cdae4 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c@@ -220,6 +220,7 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode) inode->i_private = kn; inode->i_mapping->a_ops = &kernfs_aops; inode->i_op = &kernfs_iops; + inode->i_generation = kn->generation; set_default_inode_attr(inode, kn->mode); kernfs_refresh_inode(kn, inode);
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index a9b11b8..c5f0fa7 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h@@ -135,6 +135,7 @@ struct kernfs_node { umode_t mode; unsigned int ino; struct kernfs_iattrs *iattr; + u32 generation; }; /*
@@ -170,6 +171,7 @@ struct kernfs_root { struct list_head supers; wait_queue_head_t deactivate_waitq; + atomic_t next_generation; }; struct kernfs_open_file {
--
2.9.3