sysfs, kernfs: prepare mount path for kernfs
We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
rearranges mount path so that the kernfs and sysfs parts are separate.
* As sysfs_super_info won't be visible outside kernfs proper,
kernfs_super_ns() is added to allow kernfs users to access a
super_block's namespace tag.
* Generic mount operation is separated out into kernfs_mount_ns().
sysfs_mount() now just performs sysfs-specific permission check,
acquires namespace tag, and invokes kernfs_mount_ns().
* Generic superblock release is separated out into kernfs_kill_sb()
which can be used directly as file_system_type->kill_sb(). As sysfs
needs to put the namespace tag, sysfs_kill_sb() wraps
kernfs_kill_sb() with ns tag put.
* sysfs_dir_cachep init and sysfs_inode_init() are separated out into
kernfs_init(). kernfs_init() uses only small amount of memory and
trying to handle and propagate kernfs_init() failure doesn't make
much sense. Use SLAB_PANIC for sysfs_dir_cachep and make
sysfs_inode_init() panic on failure.
After this change, kernfs_init() should be called before
sysfs_init(), fs/namespace.c::mnt_init() modified accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 9d4fab4..b4cae6f 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -37,9 +37,10 @@
.setxattr = sysfs_setxattr,
};
-int __init sysfs_inode_init(void)
+void __init sysfs_inode_init(void)
{
- return bdi_init(&sysfs_backing_dev_info);
+ if (bdi_init(&sysfs_backing_dev_info))
+ panic("failed to init sysfs_backing_dev_info");
}
static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)