From: "Eric W. Biederman" ebiederm@xmission.com
[ Upstream commit 26dbc60f385ff9cff475ea2a3bad02e80fd6fa43 ]
This prepares the way for allowing the pid part of proc to use this dcache pruning code as well.
Signed-off-by: Eric W. Biederman ebiederm@xmission.com Cc: stable@vger.kernel.org # 4.19.x Signed-off-by: Wen Yang wenyang@linux.alibaba.com --- fs/proc/inode.c | 38 ++++++++++++++++++++++++++++++++++++++ fs/proc/internal.h | 1 + fs/proc/proc_sysctl.c | 35 +---------------------------------- 3 files changed, 40 insertions(+), 34 deletions(-)
diff --git a/fs/proc/inode.c b/fs/proc/inode.c index e5334ed..fffc7e4 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -112,6 +112,44 @@ void __init proc_init_kmemcache(void) BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); }
+void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) +{ + struct inode *inode; + struct proc_inode *ei; + struct hlist_node *node; + struct super_block *sb; + + rcu_read_lock(); + for (;;) { + node = hlist_first_rcu(inodes); + if (!node) + break; + ei = hlist_entry(node, struct proc_inode, sibling_inodes); + spin_lock(lock); + hlist_del_init_rcu(&ei->sibling_inodes); + spin_unlock(lock); + + inode = &ei->vfs_inode; + sb = inode->i_sb; + if (!atomic_inc_not_zero(&sb->s_active)) + continue; + inode = igrab(inode); + rcu_read_unlock(); + if (unlikely(!inode)) { + deactivate_super(sb); + rcu_read_lock(); + continue; + } + + d_prune_aliases(inode); + iput(inode); + deactivate_super(sb); + + rcu_read_lock(); + } + rcu_read_unlock(); +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct super_block *sb = root->d_sb; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index d922c01..6cae472 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -210,6 +210,7 @@ struct pde_opener { extern const struct inode_operations proc_pid_link_inode_operations;
void proc_init_kmemcache(void); +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); void set_proc_pid_nlink(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); extern int proc_fill_super(struct super_block *, void *data, int flags); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 0f578f6..57b16bf 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -264,40 +264,7 @@ static void unuse_table(struct ctl_table_header *p)
static void proc_sys_prune_dcache(struct ctl_table_header *head) { - struct inode *inode; - struct proc_inode *ei; - struct hlist_node *node; - struct super_block *sb; - - rcu_read_lock(); - for (;;) { - node = hlist_first_rcu(&head->inodes); - if (!node) - break; - ei = hlist_entry(node, struct proc_inode, sibling_inodes); - spin_lock(&sysctl_lock); - hlist_del_init_rcu(&ei->sibling_inodes); - spin_unlock(&sysctl_lock); - - inode = &ei->vfs_inode; - sb = inode->i_sb; - if (!atomic_inc_not_zero(&sb->s_active)) - continue; - inode = igrab(inode); - rcu_read_unlock(); - if (unlikely(!inode)) { - deactivate_super(sb); - rcu_read_lock(); - continue; - } - - d_prune_aliases(inode); - iput(inode); - deactivate_super(sb); - - rcu_read_lock(); - } - rcu_read_unlock(); + proc_prune_siblings_dcache(&head->inodes, &sysctl_lock); }
/* called under sysctl_lock, will reacquire if has to wait */