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![Tejun Heo](/assets/img/avatar_default.png)
kernfs_deactivate() forgot to check whether KERNFS_LOCKDEP is set before performing lockdep annotations and ends up feeding uninitialized lockdep_map to lockdep triggering warning like the following on USB stick hotunplug. usb 1-2: USB disconnect, device number 2 INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 1 PID: 62 Comm: khubd Not tainted 3.13.0-work+ #82 Hardware name: empty empty/S3992, BIOS 080011 10/26/2007 ffff880065ca7f60 ffff88013a4ffa08 ffffffff81cfb6bd 0000000000000002 ffff88013a4ffac8 ffffffff810f8530 ffff88013a4fc710 0000000000000002 ffff880100000000 ffffffff82a3db50 0000000000000001 ffff88013a4fc710 Call Trace: [<ffffffff81cfb6bd>] dump_stack+0x4e/0x7a [<ffffffff810f8530>] __lock_acquire+0x1910/0x1e70 [<ffffffff810f931a>] lock_acquire+0x9a/0x1d0 [<ffffffff8127c75e>] kernfs_deactivate+0xee/0x130 [<ffffffff8127d4c8>] kernfs_addrm_finish+0x38/0x60 [<ffffffff8127d701>] kernfs_remove_by_name_ns+0x51/0xa0 [<ffffffff8127b4f1>] remove_files.isra.1+0x41/0x80 [<ffffffff8127b7e7>] sysfs_remove_group+0x47/0xa0 [<ffffffff8127b873>] sysfs_remove_groups+0x33/0x50 [<ffffffff8177d66d>] device_remove_attrs+0x4d/0x80 [<ffffffff8177e25e>] device_del+0x12e/0x1d0 [<ffffffff819722c2>] usb_disconnect+0x122/0x1a0 [<ffffffff819749b5>] hub_thread+0x3c5/0x1290 [<ffffffff810c6a6d>] kthread+0xed/0x110 [<ffffffff81d0a56c>] ret_from_fork+0x7c/0xb0 Fix it by making kernfs_deactivate() perform lockdep annotations only if KERNFS_LOCKDEP is set. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fabio Estevam <festevam@gmail.com> Reported-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Jiri Kosina <jkosina@suse.cz> Reported-by: Dave Jones <davej@redhat.com> Tested-by: Fabio Estevam <fabio.estevam@freescale.com> Tested-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1077 lines
25 KiB
C
1077 lines
25 KiB
C
/*
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* fs/kernfs/dir.c - kernfs directory implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/hash.h>
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#include "kernfs-internal.h"
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DEFINE_MUTEX(kernfs_mutex);
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#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
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/**
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* kernfs_name_hash
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* @name: Null terminated string to hash
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* @ns: Namespace tag to hash
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*
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* Returns 31 bit hash of ns + name (so it fits in an off_t )
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*/
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static unsigned int kernfs_name_hash(const char *name, const void *ns)
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{
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unsigned long hash = init_name_hash();
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unsigned int len = strlen(name);
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while (len--)
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hash = partial_name_hash(*name++, hash);
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hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
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hash &= 0x7fffffffU;
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/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
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if (hash < 1)
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hash += 2;
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if (hash >= INT_MAX)
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hash = INT_MAX - 1;
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return hash;
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}
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static int kernfs_name_compare(unsigned int hash, const char *name,
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const void *ns, const struct kernfs_node *kn)
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{
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if (hash != kn->hash)
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return hash - kn->hash;
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if (ns != kn->ns)
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return ns - kn->ns;
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return strcmp(name, kn->name);
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}
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static int kernfs_sd_compare(const struct kernfs_node *left,
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const struct kernfs_node *right)
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{
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return kernfs_name_compare(left->hash, left->name, left->ns, right);
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}
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/**
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* kernfs_link_sibling - link kernfs_node into sibling rbtree
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* @kn: kernfs_node of interest
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*
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* Link @kn into its sibling rbtree which starts from
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* @kn->parent->dir.children.
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*
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* Locking:
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* mutex_lock(kernfs_mutex)
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*
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* RETURNS:
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* 0 on susccess -EEXIST on failure.
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*/
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static int kernfs_link_sibling(struct kernfs_node *kn)
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{
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struct rb_node **node = &kn->parent->dir.children.rb_node;
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struct rb_node *parent = NULL;
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if (kernfs_type(kn) == KERNFS_DIR)
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kn->parent->dir.subdirs++;
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while (*node) {
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struct kernfs_node *pos;
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int result;
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pos = rb_to_kn(*node);
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parent = *node;
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result = kernfs_sd_compare(kn, pos);
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if (result < 0)
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node = &pos->rb.rb_left;
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else if (result > 0)
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node = &pos->rb.rb_right;
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else
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return -EEXIST;
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}
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/* add new node and rebalance the tree */
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rb_link_node(&kn->rb, parent, node);
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rb_insert_color(&kn->rb, &kn->parent->dir.children);
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return 0;
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}
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/**
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* kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
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* @kn: kernfs_node of interest
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*
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* Unlink @kn from its sibling rbtree which starts from
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* kn->parent->dir.children.
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*
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* Locking:
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* mutex_lock(kernfs_mutex)
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*/
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static void kernfs_unlink_sibling(struct kernfs_node *kn)
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{
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if (kernfs_type(kn) == KERNFS_DIR)
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kn->parent->dir.subdirs--;
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rb_erase(&kn->rb, &kn->parent->dir.children);
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}
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/**
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* kernfs_get_active - get an active reference to kernfs_node
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* @kn: kernfs_node to get an active reference to
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*
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* Get an active reference of @kn. This function is noop if @kn
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* is NULL.
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*
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* RETURNS:
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* Pointer to @kn on success, NULL on failure.
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*/
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struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
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{
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if (unlikely(!kn))
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return NULL;
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if (!atomic_inc_unless_negative(&kn->active))
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return NULL;
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if (kn->flags & KERNFS_LOCKDEP)
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rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
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return kn;
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}
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/**
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* kernfs_put_active - put an active reference to kernfs_node
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* @kn: kernfs_node to put an active reference to
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*
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* Put an active reference to @kn. This function is noop if @kn
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* is NULL.
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*/
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void kernfs_put_active(struct kernfs_node *kn)
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{
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int v;
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if (unlikely(!kn))
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return;
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if (kn->flags & KERNFS_LOCKDEP)
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rwsem_release(&kn->dep_map, 1, _RET_IP_);
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v = atomic_dec_return(&kn->active);
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if (likely(v != KN_DEACTIVATED_BIAS))
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return;
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/*
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* atomic_dec_return() is a mb(), we'll always see the updated
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* kn->u.completion.
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*/
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complete(kn->u.completion);
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}
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/**
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* kernfs_deactivate - deactivate kernfs_node
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* @kn: kernfs_node to deactivate
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*
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* Deny new active references and drain existing ones.
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*/
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static void kernfs_deactivate(struct kernfs_node *kn)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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int v;
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BUG_ON(!(kn->flags & KERNFS_REMOVED));
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if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
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return;
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kn->u.completion = (void *)&wait;
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if (kn->flags & KERNFS_LOCKDEP)
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rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated kn->u.completion.
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*/
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v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
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if (v != KN_DEACTIVATED_BIAS) {
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if (kn->flags & KERNFS_LOCKDEP)
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lock_contended(&kn->dep_map, _RET_IP_);
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wait_for_completion(&wait);
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}
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if (kn->flags & KERNFS_LOCKDEP) {
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lock_acquired(&kn->dep_map, _RET_IP_);
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rwsem_release(&kn->dep_map, 1, _RET_IP_);
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}
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}
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/**
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* kernfs_get - get a reference count on a kernfs_node
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* @kn: the target kernfs_node
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*/
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void kernfs_get(struct kernfs_node *kn)
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{
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if (kn) {
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WARN_ON(!atomic_read(&kn->count));
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atomic_inc(&kn->count);
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}
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}
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EXPORT_SYMBOL_GPL(kernfs_get);
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/**
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* kernfs_put - put a reference count on a kernfs_node
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* @kn: the target kernfs_node
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*
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* Put a reference count of @kn and destroy it if it reached zero.
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*/
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void kernfs_put(struct kernfs_node *kn)
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{
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struct kernfs_node *parent;
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struct kernfs_root *root;
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if (!kn || !atomic_dec_and_test(&kn->count))
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return;
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root = kernfs_root(kn);
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repeat:
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/* Moving/renaming is always done while holding reference.
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* kn->parent won't change beneath us.
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*/
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parent = kn->parent;
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WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
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parent ? parent->name : "", kn->name);
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if (kernfs_type(kn) == KERNFS_LINK)
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kernfs_put(kn->symlink.target_kn);
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if (!(kn->flags & KERNFS_STATIC_NAME))
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kfree(kn->name);
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if (kn->iattr) {
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if (kn->iattr->ia_secdata)
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security_release_secctx(kn->iattr->ia_secdata,
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kn->iattr->ia_secdata_len);
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simple_xattrs_free(&kn->iattr->xattrs);
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}
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kfree(kn->iattr);
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ida_simple_remove(&root->ino_ida, kn->ino);
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kmem_cache_free(kernfs_node_cache, kn);
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kn = parent;
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if (kn) {
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if (atomic_dec_and_test(&kn->count))
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goto repeat;
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} else {
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/* just released the root kn, free @root too */
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ida_destroy(&root->ino_ida);
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kfree(root);
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}
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}
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EXPORT_SYMBOL_GPL(kernfs_put);
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static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct kernfs_node *kn;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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/* Always perform fresh lookup for negatives */
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if (!dentry->d_inode)
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goto out_bad_unlocked;
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kn = dentry->d_fsdata;
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mutex_lock(&kernfs_mutex);
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/* The kernfs node has been deleted */
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if (kn->flags & KERNFS_REMOVED)
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goto out_bad;
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/* The kernfs node has been moved? */
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if (dentry->d_parent->d_fsdata != kn->parent)
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goto out_bad;
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/* The kernfs node has been renamed */
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if (strcmp(dentry->d_name.name, kn->name) != 0)
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goto out_bad;
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/* The kernfs node has been moved to a different namespace */
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if (kn->parent && kernfs_ns_enabled(kn->parent) &&
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kernfs_info(dentry->d_sb)->ns != kn->ns)
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goto out_bad;
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mutex_unlock(&kernfs_mutex);
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out_valid:
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return 1;
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out_bad:
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mutex_unlock(&kernfs_mutex);
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out_bad_unlocked:
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/*
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* @dentry doesn't match the underlying kernfs node, drop the
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* dentry and force lookup. If we have submounts we must allow the
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* vfs caches to lie about the state of the filesystem to prevent
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* leaks and other nasty things, so use check_submounts_and_drop()
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* instead of d_drop().
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*/
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if (check_submounts_and_drop(dentry) != 0)
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goto out_valid;
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return 0;
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}
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static void kernfs_dop_release(struct dentry *dentry)
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{
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kernfs_put(dentry->d_fsdata);
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}
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const struct dentry_operations kernfs_dops = {
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.d_revalidate = kernfs_dop_revalidate,
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.d_release = kernfs_dop_release,
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};
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static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
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const char *name, umode_t mode,
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unsigned flags)
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{
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char *dup_name = NULL;
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struct kernfs_node *kn;
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int ret;
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if (!(flags & KERNFS_STATIC_NAME)) {
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name = dup_name = kstrdup(name, GFP_KERNEL);
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if (!name)
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return NULL;
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}
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kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
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if (!kn)
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goto err_out1;
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ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
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if (ret < 0)
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goto err_out2;
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kn->ino = ret;
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atomic_set(&kn->count, 1);
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atomic_set(&kn->active, 0);
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kn->name = name;
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kn->mode = mode;
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kn->flags = flags | KERNFS_REMOVED;
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return kn;
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err_out2:
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kmem_cache_free(kernfs_node_cache, kn);
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err_out1:
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kfree(dup_name);
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return NULL;
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}
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struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
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const char *name, umode_t mode,
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unsigned flags)
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{
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struct kernfs_node *kn;
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kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
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if (kn) {
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kernfs_get(parent);
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kn->parent = parent;
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}
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return kn;
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}
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/**
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* kernfs_addrm_start - prepare for kernfs_node add/remove
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* @acxt: pointer to kernfs_addrm_cxt to be used
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*
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* This function is called when the caller is about to add or remove
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* kernfs_node. This function acquires kernfs_mutex. @acxt is used
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* to keep and pass context to other addrm functions.
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*
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* LOCKING:
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* Kernel thread context (may sleep). kernfs_mutex is locked on
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* return.
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*/
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void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
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__acquires(kernfs_mutex)
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{
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memset(acxt, 0, sizeof(*acxt));
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mutex_lock(&kernfs_mutex);
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}
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/**
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* kernfs_add_one - add kernfs_node to parent without warning
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* @acxt: addrm context to use
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* @kn: kernfs_node to be added
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*
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* The caller must already have initialized @kn->parent. This
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* function increments nlink of the parent's inode if @kn is a
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* directory and link into the children list of the parent.
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*
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* This function should be called between calls to
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* kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
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* the same @acxt as passed to kernfs_addrm_start().
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*
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* LOCKING:
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* Determined by kernfs_addrm_start().
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*
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* RETURNS:
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* 0 on success, -EEXIST if entry with the given name already
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* exists.
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*/
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int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
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{
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struct kernfs_node *parent = kn->parent;
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bool has_ns = kernfs_ns_enabled(parent);
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struct kernfs_iattrs *ps_iattr;
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int ret;
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if (has_ns != (bool)kn->ns) {
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WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
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has_ns ? "required" : "invalid", parent->name, kn->name);
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return -EINVAL;
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}
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|
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if (kernfs_type(parent) != KERNFS_DIR)
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return -EINVAL;
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|
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if (parent->flags & KERNFS_REMOVED)
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return -ENOENT;
|
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|
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kn->hash = kernfs_name_hash(kn->name, kn->ns);
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|
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ret = kernfs_link_sibling(kn);
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if (ret)
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return ret;
|
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|
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/* Update timestamps on the parent */
|
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ps_iattr = parent->iattr;
|
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if (ps_iattr) {
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struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
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ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
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}
|
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|
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/* Mark the entry added into directory tree */
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kn->flags &= ~KERNFS_REMOVED;
|
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|
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return 0;
|
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}
|
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|
|
/**
|
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* kernfs_remove_one - remove kernfs_node from parent
|
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* @acxt: addrm context to use
|
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* @kn: kernfs_node to be removed
|
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*
|
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* Mark @kn removed and drop nlink of parent inode if @kn is a
|
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* directory. @kn is unlinked from the children list.
|
|
*
|
|
* This function should be called between calls to
|
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* kernfs_addrm_start() and kernfs_addrm_finish() and should be
|
|
* passed the same @acxt as passed to kernfs_addrm_start().
|
|
*
|
|
* LOCKING:
|
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* Determined by kernfs_addrm_start().
|
|
*/
|
|
static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
|
|
struct kernfs_node *kn)
|
|
{
|
|
struct kernfs_iattrs *ps_iattr;
|
|
|
|
/*
|
|
* Removal can be called multiple times on the same node. Only the
|
|
* first invocation is effective and puts the base ref.
|
|
*/
|
|
if (kn->flags & KERNFS_REMOVED)
|
|
return;
|
|
|
|
if (kn->parent) {
|
|
kernfs_unlink_sibling(kn);
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = kn->parent->iattr;
|
|
if (ps_iattr) {
|
|
ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
|
|
ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
|
|
}
|
|
}
|
|
|
|
kn->flags |= KERNFS_REMOVED;
|
|
kn->u.removed_list = acxt->removed;
|
|
acxt->removed = kn;
|
|
}
|
|
|
|
/**
|
|
* kernfs_addrm_finish - finish up kernfs_node add/remove
|
|
* @acxt: addrm context to finish up
|
|
*
|
|
* Finish up kernfs_node add/remove. Resources acquired by
|
|
* kernfs_addrm_start() are released and removed kernfs_nodes are
|
|
* cleaned up.
|
|
*
|
|
* LOCKING:
|
|
* kernfs_mutex is released.
|
|
*/
|
|
void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
|
|
__releases(kernfs_mutex)
|
|
{
|
|
/* release resources acquired by kernfs_addrm_start() */
|
|
mutex_unlock(&kernfs_mutex);
|
|
|
|
/* kill removed kernfs_nodes */
|
|
while (acxt->removed) {
|
|
struct kernfs_node *kn = acxt->removed;
|
|
|
|
acxt->removed = kn->u.removed_list;
|
|
|
|
kernfs_deactivate(kn);
|
|
kernfs_unmap_bin_file(kn);
|
|
kernfs_put(kn);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* kernfs_find_ns - find kernfs_node with the given name
|
|
* @parent: kernfs_node to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for kernfs_node with name @name under @parent. Returns pointer to
|
|
* the found kernfs_node on success, %NULL on failure.
|
|
*/
|
|
static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
|
|
const unsigned char *name,
|
|
const void *ns)
|
|
{
|
|
struct rb_node *node = parent->dir.children.rb_node;
|
|
bool has_ns = kernfs_ns_enabled(parent);
|
|
unsigned int hash;
|
|
|
|
lockdep_assert_held(&kernfs_mutex);
|
|
|
|
if (has_ns != (bool)ns) {
|
|
WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
|
|
has_ns ? "required" : "invalid", parent->name, name);
|
|
return NULL;
|
|
}
|
|
|
|
hash = kernfs_name_hash(name, ns);
|
|
while (node) {
|
|
struct kernfs_node *kn;
|
|
int result;
|
|
|
|
kn = rb_to_kn(node);
|
|
result = kernfs_name_compare(hash, name, ns, kn);
|
|
if (result < 0)
|
|
node = node->rb_left;
|
|
else if (result > 0)
|
|
node = node->rb_right;
|
|
else
|
|
return kn;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* kernfs_find_and_get_ns - find and get kernfs_node with the given name
|
|
* @parent: kernfs_node to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for kernfs_node with name @name under @parent and get a reference
|
|
* if found. This function may sleep and returns pointer to the found
|
|
* kernfs_node on success, %NULL on failure.
|
|
*/
|
|
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
|
|
const char *name, const void *ns)
|
|
{
|
|
struct kernfs_node *kn;
|
|
|
|
mutex_lock(&kernfs_mutex);
|
|
kn = kernfs_find_ns(parent, name, ns);
|
|
kernfs_get(kn);
|
|
mutex_unlock(&kernfs_mutex);
|
|
|
|
return kn;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
|
|
|
|
/**
|
|
* kernfs_create_root - create a new kernfs hierarchy
|
|
* @kdops: optional directory syscall operations for the hierarchy
|
|
* @priv: opaque data associated with the new directory
|
|
*
|
|
* Returns the root of the new hierarchy on success, ERR_PTR() value on
|
|
* failure.
|
|
*/
|
|
struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
|
|
{
|
|
struct kernfs_root *root;
|
|
struct kernfs_node *kn;
|
|
|
|
root = kzalloc(sizeof(*root), GFP_KERNEL);
|
|
if (!root)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ida_init(&root->ino_ida);
|
|
|
|
kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
|
|
KERNFS_DIR);
|
|
if (!kn) {
|
|
ida_destroy(&root->ino_ida);
|
|
kfree(root);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
kn->flags &= ~KERNFS_REMOVED;
|
|
kn->priv = priv;
|
|
kn->dir.root = root;
|
|
|
|
root->dir_ops = kdops;
|
|
root->kn = kn;
|
|
|
|
return root;
|
|
}
|
|
|
|
/**
|
|
* kernfs_destroy_root - destroy a kernfs hierarchy
|
|
* @root: root of the hierarchy to destroy
|
|
*
|
|
* Destroy the hierarchy anchored at @root by removing all existing
|
|
* directories and destroying @root.
|
|
*/
|
|
void kernfs_destroy_root(struct kernfs_root *root)
|
|
{
|
|
kernfs_remove(root->kn); /* will also free @root */
|
|
}
|
|
|
|
/**
|
|
* kernfs_create_dir_ns - create a directory
|
|
* @parent: parent in which to create a new directory
|
|
* @name: name of the new directory
|
|
* @mode: mode of the new directory
|
|
* @priv: opaque data associated with the new directory
|
|
* @ns: optional namespace tag of the directory
|
|
*
|
|
* Returns the created node on success, ERR_PTR() value on failure.
|
|
*/
|
|
struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
|
|
const char *name, umode_t mode,
|
|
void *priv, const void *ns)
|
|
{
|
|
struct kernfs_addrm_cxt acxt;
|
|
struct kernfs_node *kn;
|
|
int rc;
|
|
|
|
/* allocate */
|
|
kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
|
|
if (!kn)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
kn->dir.root = parent->dir.root;
|
|
kn->ns = ns;
|
|
kn->priv = priv;
|
|
|
|
/* link in */
|
|
kernfs_addrm_start(&acxt);
|
|
rc = kernfs_add_one(&acxt, kn);
|
|
kernfs_addrm_finish(&acxt);
|
|
|
|
if (!rc)
|
|
return kn;
|
|
|
|
kernfs_put(kn);
|
|
return ERR_PTR(rc);
|
|
}
|
|
|
|
static struct dentry *kernfs_iop_lookup(struct inode *dir,
|
|
struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct dentry *ret;
|
|
struct kernfs_node *parent = dentry->d_parent->d_fsdata;
|
|
struct kernfs_node *kn;
|
|
struct inode *inode;
|
|
const void *ns = NULL;
|
|
|
|
mutex_lock(&kernfs_mutex);
|
|
|
|
if (kernfs_ns_enabled(parent))
|
|
ns = kernfs_info(dir->i_sb)->ns;
|
|
|
|
kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
|
|
|
|
/* no such entry */
|
|
if (!kn) {
|
|
ret = NULL;
|
|
goto out_unlock;
|
|
}
|
|
kernfs_get(kn);
|
|
dentry->d_fsdata = kn;
|
|
|
|
/* attach dentry and inode */
|
|
inode = kernfs_get_inode(dir->i_sb, kn);
|
|
if (!inode) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* instantiate and hash dentry */
|
|
ret = d_materialise_unique(dentry, inode);
|
|
out_unlock:
|
|
mutex_unlock(&kernfs_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
|
|
umode_t mode)
|
|
{
|
|
struct kernfs_node *parent = dir->i_private;
|
|
struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
|
|
|
|
if (!kdops || !kdops->mkdir)
|
|
return -EPERM;
|
|
|
|
return kdops->mkdir(parent, dentry->d_name.name, mode);
|
|
}
|
|
|
|
static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
struct kernfs_node *kn = dentry->d_fsdata;
|
|
struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
|
|
|
|
if (!kdops || !kdops->rmdir)
|
|
return -EPERM;
|
|
|
|
return kdops->rmdir(kn);
|
|
}
|
|
|
|
static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
|
|
struct inode *new_dir, struct dentry *new_dentry)
|
|
{
|
|
struct kernfs_node *kn = old_dentry->d_fsdata;
|
|
struct kernfs_node *new_parent = new_dir->i_private;
|
|
struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
|
|
|
|
if (!kdops || !kdops->rename)
|
|
return -EPERM;
|
|
|
|
return kdops->rename(kn, new_parent, new_dentry->d_name.name);
|
|
}
|
|
|
|
const struct inode_operations kernfs_dir_iops = {
|
|
.lookup = kernfs_iop_lookup,
|
|
.permission = kernfs_iop_permission,
|
|
.setattr = kernfs_iop_setattr,
|
|
.getattr = kernfs_iop_getattr,
|
|
.setxattr = kernfs_iop_setxattr,
|
|
.removexattr = kernfs_iop_removexattr,
|
|
.getxattr = kernfs_iop_getxattr,
|
|
.listxattr = kernfs_iop_listxattr,
|
|
|
|
.mkdir = kernfs_iop_mkdir,
|
|
.rmdir = kernfs_iop_rmdir,
|
|
.rename = kernfs_iop_rename,
|
|
};
|
|
|
|
static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
|
|
{
|
|
struct kernfs_node *last;
|
|
|
|
while (true) {
|
|
struct rb_node *rbn;
|
|
|
|
last = pos;
|
|
|
|
if (kernfs_type(pos) != KERNFS_DIR)
|
|
break;
|
|
|
|
rbn = rb_first(&pos->dir.children);
|
|
if (!rbn)
|
|
break;
|
|
|
|
pos = rb_to_kn(rbn);
|
|
}
|
|
|
|
return last;
|
|
}
|
|
|
|
/**
|
|
* kernfs_next_descendant_post - find the next descendant for post-order walk
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @root: kernfs_node whose descendants to walk
|
|
*
|
|
* Find the next descendant to visit for post-order traversal of @root's
|
|
* descendants. @root is included in the iteration and the last node to be
|
|
* visited.
|
|
*/
|
|
static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
|
|
struct kernfs_node *root)
|
|
{
|
|
struct rb_node *rbn;
|
|
|
|
lockdep_assert_held(&kernfs_mutex);
|
|
|
|
/* if first iteration, visit leftmost descendant which may be root */
|
|
if (!pos)
|
|
return kernfs_leftmost_descendant(root);
|
|
|
|
/* if we visited @root, we're done */
|
|
if (pos == root)
|
|
return NULL;
|
|
|
|
/* if there's an unvisited sibling, visit its leftmost descendant */
|
|
rbn = rb_next(&pos->rb);
|
|
if (rbn)
|
|
return kernfs_leftmost_descendant(rb_to_kn(rbn));
|
|
|
|
/* no sibling left, visit parent */
|
|
return pos->parent;
|
|
}
|
|
|
|
static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
|
|
struct kernfs_node *kn)
|
|
{
|
|
struct kernfs_node *pos, *next;
|
|
|
|
if (!kn)
|
|
return;
|
|
|
|
pr_debug("kernfs %s: removing\n", kn->name);
|
|
|
|
next = NULL;
|
|
do {
|
|
pos = next;
|
|
next = kernfs_next_descendant_post(pos, kn);
|
|
if (pos)
|
|
kernfs_remove_one(acxt, pos);
|
|
} while (next);
|
|
}
|
|
|
|
/**
|
|
* kernfs_remove - remove a kernfs_node recursively
|
|
* @kn: the kernfs_node to remove
|
|
*
|
|
* Remove @kn along with all its subdirectories and files.
|
|
*/
|
|
void kernfs_remove(struct kernfs_node *kn)
|
|
{
|
|
struct kernfs_addrm_cxt acxt;
|
|
|
|
kernfs_addrm_start(&acxt);
|
|
__kernfs_remove(&acxt, kn);
|
|
kernfs_addrm_finish(&acxt);
|
|
}
|
|
|
|
/**
|
|
* kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
|
|
* @parent: parent of the target
|
|
* @name: name of the kernfs_node to remove
|
|
* @ns: namespace tag of the kernfs_node to remove
|
|
*
|
|
* Look for the kernfs_node with @name and @ns under @parent and remove it.
|
|
* Returns 0 on success, -ENOENT if such entry doesn't exist.
|
|
*/
|
|
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
|
|
const void *ns)
|
|
{
|
|
struct kernfs_addrm_cxt acxt;
|
|
struct kernfs_node *kn;
|
|
|
|
if (!parent) {
|
|
WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
|
|
name);
|
|
return -ENOENT;
|
|
}
|
|
|
|
kernfs_addrm_start(&acxt);
|
|
|
|
kn = kernfs_find_ns(parent, name, ns);
|
|
if (kn)
|
|
__kernfs_remove(&acxt, kn);
|
|
|
|
kernfs_addrm_finish(&acxt);
|
|
|
|
if (kn)
|
|
return 0;
|
|
else
|
|
return -ENOENT;
|
|
}
|
|
|
|
/**
|
|
* kernfs_rename_ns - move and rename a kernfs_node
|
|
* @kn: target node
|
|
* @new_parent: new parent to put @sd under
|
|
* @new_name: new name
|
|
* @new_ns: new namespace tag
|
|
*/
|
|
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
|
|
const char *new_name, const void *new_ns)
|
|
{
|
|
int error;
|
|
|
|
mutex_lock(&kernfs_mutex);
|
|
|
|
error = -ENOENT;
|
|
if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
|
|
goto out;
|
|
|
|
error = 0;
|
|
if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
|
|
(strcmp(kn->name, new_name) == 0))
|
|
goto out; /* nothing to rename */
|
|
|
|
error = -EEXIST;
|
|
if (kernfs_find_ns(new_parent, new_name, new_ns))
|
|
goto out;
|
|
|
|
/* rename kernfs_node */
|
|
if (strcmp(kn->name, new_name) != 0) {
|
|
error = -ENOMEM;
|
|
new_name = kstrdup(new_name, GFP_KERNEL);
|
|
if (!new_name)
|
|
goto out;
|
|
|
|
if (kn->flags & KERNFS_STATIC_NAME)
|
|
kn->flags &= ~KERNFS_STATIC_NAME;
|
|
else
|
|
kfree(kn->name);
|
|
|
|
kn->name = new_name;
|
|
}
|
|
|
|
/*
|
|
* Move to the appropriate place in the appropriate directories rbtree.
|
|
*/
|
|
kernfs_unlink_sibling(kn);
|
|
kernfs_get(new_parent);
|
|
kernfs_put(kn->parent);
|
|
kn->ns = new_ns;
|
|
kn->hash = kernfs_name_hash(kn->name, kn->ns);
|
|
kn->parent = new_parent;
|
|
kernfs_link_sibling(kn);
|
|
|
|
error = 0;
|
|
out:
|
|
mutex_unlock(&kernfs_mutex);
|
|
return error;
|
|
}
|
|
|
|
/* Relationship between s_mode and the DT_xxx types */
|
|
static inline unsigned char dt_type(struct kernfs_node *kn)
|
|
{
|
|
return (kn->mode >> 12) & 15;
|
|
}
|
|
|
|
static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
|
|
{
|
|
kernfs_put(filp->private_data);
|
|
return 0;
|
|
}
|
|
|
|
static struct kernfs_node *kernfs_dir_pos(const void *ns,
|
|
struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
|
|
{
|
|
if (pos) {
|
|
int valid = !(pos->flags & KERNFS_REMOVED) &&
|
|
pos->parent == parent && hash == pos->hash;
|
|
kernfs_put(pos);
|
|
if (!valid)
|
|
pos = NULL;
|
|
}
|
|
if (!pos && (hash > 1) && (hash < INT_MAX)) {
|
|
struct rb_node *node = parent->dir.children.rb_node;
|
|
while (node) {
|
|
pos = rb_to_kn(node);
|
|
|
|
if (hash < pos->hash)
|
|
node = node->rb_left;
|
|
else if (hash > pos->hash)
|
|
node = node->rb_right;
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
/* Skip over entries in the wrong namespace */
|
|
while (pos && pos->ns != ns) {
|
|
struct rb_node *node = rb_next(&pos->rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = rb_to_kn(node);
|
|
}
|
|
return pos;
|
|
}
|
|
|
|
static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
|
|
struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
|
|
{
|
|
pos = kernfs_dir_pos(ns, parent, ino, pos);
|
|
if (pos)
|
|
do {
|
|
struct rb_node *node = rb_next(&pos->rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = rb_to_kn(node);
|
|
} while (pos && pos->ns != ns);
|
|
return pos;
|
|
}
|
|
|
|
static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
struct dentry *dentry = file->f_path.dentry;
|
|
struct kernfs_node *parent = dentry->d_fsdata;
|
|
struct kernfs_node *pos = file->private_data;
|
|
const void *ns = NULL;
|
|
|
|
if (!dir_emit_dots(file, ctx))
|
|
return 0;
|
|
mutex_lock(&kernfs_mutex);
|
|
|
|
if (kernfs_ns_enabled(parent))
|
|
ns = kernfs_info(dentry->d_sb)->ns;
|
|
|
|
for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
|
|
pos;
|
|
pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
|
|
const char *name = pos->name;
|
|
unsigned int type = dt_type(pos);
|
|
int len = strlen(name);
|
|
ino_t ino = pos->ino;
|
|
|
|
ctx->pos = pos->hash;
|
|
file->private_data = pos;
|
|
kernfs_get(pos);
|
|
|
|
mutex_unlock(&kernfs_mutex);
|
|
if (!dir_emit(ctx, name, len, ino, type))
|
|
return 0;
|
|
mutex_lock(&kernfs_mutex);
|
|
}
|
|
mutex_unlock(&kernfs_mutex);
|
|
file->private_data = NULL;
|
|
ctx->pos = INT_MAX;
|
|
return 0;
|
|
}
|
|
|
|
static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
|
|
int whence)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
loff_t ret;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
ret = generic_file_llseek(file, offset, whence);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct file_operations kernfs_dir_fops = {
|
|
.read = generic_read_dir,
|
|
.iterate = kernfs_fop_readdir,
|
|
.release = kernfs_dir_fop_release,
|
|
.llseek = kernfs_dir_fop_llseek,
|
|
};
|