[PATCH v2 2/6] proc: Generalize proc_sys_prune_dcache into proc_prune_siblings_dcache
From: Eric W. Biederman <hidden>
Date: 2020-02-24 16:29:27
Also in:
linux-fsdevel, linux-security-module, lkml
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, proc sysctl, the rest · Maintainers:
Alexander Viro, Christian Brauner, Kees Cook, Joel Granados, Linus Torvalds
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 <redacted> --- 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 bdae442d5262..74ce4a8d05eb 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c@@ -103,6 +103,44 @@ 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 366cd3aa690b..ba9a991824a5 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h@@ -210,6 +210,7 @@ extern const struct inode_operations proc_pid_link_inode_operations; extern const struct super_operations proc_sops; 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 void proc_entry_rundown(struct proc_dir_entry *);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 42fbb7f3c587..5da9d7f7ae34 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c@@ -269,40 +269,7 @@ 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 */
--
2.25.0