From f41c593454943b80a2017c8a2a3d6b1d0b0a6f89 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 14 Feb 2014 16:57:27 +0800 Subject: [PATCH] kernfs: fix kernfs_node_from_dentry() Currently kernfs_node_from_dentry() returns NULL for root dentry, because root_dentry->d_op == NULL. Due to this bug cgroupstats_build() returns -EINVAL for root cgroup. # mount -t cgroup -o cpuacct /cgroup # Documentation/accounting/getdelays -C /cgroup fatal reply error, errno -22 With this fix: # Documentation/accounting/getdelays -C /cgroup sleeping 305, blocked 0, running 1, stopped 0, uninterruptible 1 Signed-off-by: Li Zefan Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/dir.c | 2 +- fs/kernfs/kernfs-internal.h | 1 + fs/kernfs/mount.c | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index a0f99b7f84b2..8245d3b34894 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -500,7 +500,7 @@ const struct dentry_operations kernfs_dops = { */ struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) { - if (dentry->d_op == &kernfs_dops) + if (dentry->d_sb->s_op == &kernfs_sops) return dentry->d_fsdata; return NULL; } diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index a91d7a1113d9..8be13b2a079b 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -65,6 +65,7 @@ struct kernfs_super_info { }; #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info)) +extern const struct super_operations kernfs_sops; extern struct kmem_cache *kernfs_node_cache; /* diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index e5b28b0ebc37..405279b5517b 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -39,7 +39,7 @@ static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry) return 0; } -static const struct super_operations kernfs_sops = { +const struct super_operations kernfs_sops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .evict_inode = kernfs_evict_inode,