![Stephen Hemminger](/assets/img/avatar_default.png)
It is possible that the entry in sysfs already exists, one case of this is when a network device is renamed to bonding_masters. Anyway, in this case the proper error path is for device_rename to return an error code, not to generate bogus backtrace and errors. Also, to avoid possible races, the create link should be done before the remove link. This makes a device rename atomic operation like other renames. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net>
961 lines
22 KiB
C
961 lines
22 KiB
C
/*
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* fs/sysfs/dir.c - sysfs core and dir operation 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 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#undef DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include <linux/completion.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include "sysfs.h"
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DEFINE_MUTEX(sysfs_mutex);
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DEFINE_MUTEX(sysfs_rename_mutex);
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DEFINE_SPINLOCK(sysfs_assoc_lock);
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static DEFINE_SPINLOCK(sysfs_ino_lock);
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static DEFINE_IDA(sysfs_ino_ida);
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/**
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* sysfs_link_sibling - link sysfs_dirent into sibling list
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* @sd: sysfs_dirent of interest
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*
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* Link @sd into its sibling list which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*/
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static void sysfs_link_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent *parent_sd = sd->s_parent;
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struct sysfs_dirent **pos;
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BUG_ON(sd->s_sibling);
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/* Store directory entries in order by ino. This allows
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* readdir to properly restart without having to add a
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* cursor into the s_dir.children list.
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*/
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for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
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if (sd->s_ino < (*pos)->s_ino)
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break;
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}
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sd->s_sibling = *pos;
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*pos = sd;
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}
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/**
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* sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
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* @sd: sysfs_dirent of interest
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*
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* Unlink @sd from its sibling list which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*/
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static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent **pos;
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for (pos = &sd->s_parent->s_dir.children; *pos;
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pos = &(*pos)->s_sibling) {
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if (*pos == sd) {
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*pos = sd->s_sibling;
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sd->s_sibling = NULL;
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break;
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}
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}
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}
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/**
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* sysfs_get_dentry - get dentry for the given sysfs_dirent
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* @sd: sysfs_dirent of interest
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*
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* Get dentry for @sd. Dentry is looked up if currently not
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* present. This function descends from the root looking up
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* dentry for each step.
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*
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* LOCKING:
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* mutex_lock(sysfs_rename_mutex)
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*
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* RETURNS:
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* Pointer to found dentry on success, ERR_PTR() value on error.
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*/
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struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
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{
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struct dentry *dentry = dget(sysfs_sb->s_root);
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while (dentry->d_fsdata != sd) {
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struct sysfs_dirent *cur;
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struct dentry *parent;
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/* find the first ancestor which hasn't been looked up */
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cur = sd;
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while (cur->s_parent != dentry->d_fsdata)
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cur = cur->s_parent;
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/* look it up */
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parent = dentry;
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mutex_lock(&parent->d_inode->i_mutex);
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dentry = lookup_one_noperm(cur->s_name, parent);
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mutex_unlock(&parent->d_inode->i_mutex);
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dput(parent);
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if (IS_ERR(dentry))
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break;
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}
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return dentry;
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}
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/**
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* sysfs_get_active - get an active reference to sysfs_dirent
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* @sd: sysfs_dirent to get an active reference to
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*
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* Get an active reference of @sd. This function is noop if @sd
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* is NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
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{
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if (unlikely(!sd))
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return NULL;
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while (1) {
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int v, t;
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v = atomic_read(&sd->s_active);
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if (unlikely(v < 0))
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return NULL;
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t = atomic_cmpxchg(&sd->s_active, v, v + 1);
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if (likely(t == v))
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return sd;
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if (t < 0)
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return NULL;
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cpu_relax();
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}
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}
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/**
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* sysfs_put_active - put an active reference to sysfs_dirent
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* @sd: sysfs_dirent to put an active reference to
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*
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* Put an active reference to @sd. This function is noop if @sd
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* is NULL.
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*/
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static void sysfs_put_active(struct sysfs_dirent *sd)
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{
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struct completion *cmpl;
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int v;
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if (unlikely(!sd))
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return;
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v = atomic_dec_return(&sd->s_active);
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if (likely(v != SD_DEACTIVATED_BIAS))
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return;
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/* atomic_dec_return() is a mb(), we'll always see the updated
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* sd->s_sibling.
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*/
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cmpl = (void *)sd->s_sibling;
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complete(cmpl);
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}
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/**
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* sysfs_get_active_two - get active references to sysfs_dirent and parent
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* @sd: sysfs_dirent of interest
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*
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* Get active reference to @sd and its parent. Parent's active
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* reference is grabbed first. This function is noop if @sd is
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* NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
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{
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if (sd) {
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if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
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return NULL;
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if (unlikely(!sysfs_get_active(sd))) {
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sysfs_put_active(sd->s_parent);
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return NULL;
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}
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}
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return sd;
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}
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/**
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* sysfs_put_active_two - put active references to sysfs_dirent and parent
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* @sd: sysfs_dirent of interest
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*
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* Put active references to @sd and its parent. This function is
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* noop if @sd is NULL.
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*/
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void sysfs_put_active_two(struct sysfs_dirent *sd)
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{
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if (sd) {
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sysfs_put_active(sd);
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sysfs_put_active(sd->s_parent);
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}
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}
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/**
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* sysfs_deactivate - deactivate sysfs_dirent
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* @sd: sysfs_dirent 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 sysfs_deactivate(struct sysfs_dirent *sd)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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int v;
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BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
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sd->s_sibling = (void *)&wait;
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated sd->s_sibling.
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*/
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v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
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if (v != SD_DEACTIVATED_BIAS)
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wait_for_completion(&wait);
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sd->s_sibling = NULL;
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}
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static int sysfs_alloc_ino(ino_t *pino)
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{
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int ino, rc;
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retry:
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spin_lock(&sysfs_ino_lock);
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rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
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spin_unlock(&sysfs_ino_lock);
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if (rc == -EAGAIN) {
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if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
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goto retry;
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rc = -ENOMEM;
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}
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*pino = ino;
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return rc;
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}
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static void sysfs_free_ino(ino_t ino)
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{
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spin_lock(&sysfs_ino_lock);
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ida_remove(&sysfs_ino_ida, ino);
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spin_unlock(&sysfs_ino_lock);
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}
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void release_sysfs_dirent(struct sysfs_dirent * sd)
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{
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struct sysfs_dirent *parent_sd;
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repeat:
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/* Moving/renaming is always done while holding reference.
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* sd->s_parent won't change beneath us.
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*/
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parent_sd = sd->s_parent;
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if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
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sysfs_put(sd->s_symlink.target_sd);
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if (sysfs_type(sd) & SYSFS_COPY_NAME)
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kfree(sd->s_name);
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kfree(sd->s_iattr);
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sysfs_free_ino(sd->s_ino);
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kmem_cache_free(sysfs_dir_cachep, sd);
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sd = parent_sd;
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if (sd && atomic_dec_and_test(&sd->s_count))
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goto repeat;
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}
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static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
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{
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struct sysfs_dirent * sd = dentry->d_fsdata;
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sysfs_put(sd);
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iput(inode);
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}
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static struct dentry_operations sysfs_dentry_ops = {
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.d_iput = sysfs_d_iput,
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};
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struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
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{
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char *dup_name = NULL;
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struct sysfs_dirent *sd;
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if (type & SYSFS_COPY_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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sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
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if (!sd)
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goto err_out1;
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if (sysfs_alloc_ino(&sd->s_ino))
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goto err_out2;
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atomic_set(&sd->s_count, 1);
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atomic_set(&sd->s_active, 0);
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sd->s_name = name;
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sd->s_mode = mode;
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sd->s_flags = type;
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return sd;
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err_out2:
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kmem_cache_free(sysfs_dir_cachep, sd);
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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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static int sysfs_ilookup_test(struct inode *inode, void *arg)
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{
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struct sysfs_dirent *sd = arg;
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return inode->i_ino == sd->s_ino;
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}
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/**
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* sysfs_addrm_start - prepare for sysfs_dirent add/remove
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* @acxt: pointer to sysfs_addrm_cxt to be used
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* @parent_sd: parent sysfs_dirent
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*
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* This function is called when the caller is about to add or
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* remove sysfs_dirent under @parent_sd. This function acquires
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* sysfs_mutex, grabs inode for @parent_sd if available and lock
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* i_mutex of it. @acxt is used to keep and pass context to
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* other addrm functions.
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*
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* LOCKING:
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* Kernel thread context (may sleep). sysfs_mutex is locked on
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* return. i_mutex of parent inode is locked on return if
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* available.
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*/
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void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
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struct sysfs_dirent *parent_sd)
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{
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struct inode *inode;
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memset(acxt, 0, sizeof(*acxt));
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acxt->parent_sd = parent_sd;
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/* Lookup parent inode. inode initialization and I_NEW
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* clearing are protected by sysfs_mutex. By grabbing it and
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* looking up with _nowait variant, inode state can be
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* determined reliably.
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*/
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mutex_lock(&sysfs_mutex);
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inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test,
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parent_sd);
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if (inode && !(inode->i_state & I_NEW)) {
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/* parent inode available */
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acxt->parent_inode = inode;
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/* sysfs_mutex is below i_mutex in lock hierarchy.
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* First, trylock i_mutex. If fails, unlock
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* sysfs_mutex and lock them in order.
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*/
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if (!mutex_trylock(&inode->i_mutex)) {
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mutex_unlock(&sysfs_mutex);
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mutex_lock(&inode->i_mutex);
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mutex_lock(&sysfs_mutex);
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}
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} else
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iput(inode);
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}
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/**
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* sysfs_add_one - add sysfs_dirent to parent
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* @acxt: addrm context to use
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* @sd: sysfs_dirent to be added
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*
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* Get @acxt->parent_sd and set sd->s_parent to it and increment
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* nlink of parent inode if @sd is a directory and link into the
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* 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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* sysfs_addrm_start() and sysfs_addrm_finish() and should be
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* passed the same @acxt as passed to sysfs_addrm_start().
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*
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* LOCKING:
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* Determined by sysfs_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 sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
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{
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if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
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return -EEXIST;
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sd->s_parent = sysfs_get(acxt->parent_sd);
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if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
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inc_nlink(acxt->parent_inode);
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acxt->cnt++;
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|
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sysfs_link_sibling(sd);
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|
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return 0;
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}
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|
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/**
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* sysfs_remove_one - remove sysfs_dirent from parent
|
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* @acxt: addrm context to use
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* @sd: sysfs_dirent to be removed
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*
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* Mark @sd removed and drop nlink of parent inode if @sd is a
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* directory. @sd is unlinked from the children list.
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*
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* This function should be called between calls to
|
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* sysfs_addrm_start() and sysfs_addrm_finish() and should be
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* passed the same @acxt as passed to sysfs_addrm_start().
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*
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* LOCKING:
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* Determined by sysfs_addrm_start().
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*/
|
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void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
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{
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BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
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|
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sysfs_unlink_sibling(sd);
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|
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sd->s_flags |= SYSFS_FLAG_REMOVED;
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sd->s_sibling = acxt->removed;
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acxt->removed = sd;
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|
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if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
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drop_nlink(acxt->parent_inode);
|
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|
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acxt->cnt++;
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}
|
|
|
|
/**
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* sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
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* @sd: target sysfs_dirent
|
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*
|
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* Drop dentry for @sd. @sd must have been unlinked from its
|
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* parent on entry to this function such that it can't be looked
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* up anymore.
|
|
*/
|
|
static void sysfs_drop_dentry(struct sysfs_dirent *sd)
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{
|
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struct inode *inode;
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struct dentry *dentry;
|
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|
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inode = ilookup(sysfs_sb, sd->s_ino);
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if (!inode)
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return;
|
|
|
|
/* Drop any existing dentries associated with sd.
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*
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|
* For the dentry to be properly freed we need to grab a
|
|
* reference to the dentry under the dcache lock, unhash it,
|
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* and then put it. The playing with the dentry count allows
|
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* dput to immediately free the dentry if it is not in use.
|
|
*/
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|
repeat:
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spin_lock(&dcache_lock);
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list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
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if (d_unhashed(dentry))
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continue;
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dget_locked(dentry);
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spin_lock(&dentry->d_lock);
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__d_drop(dentry);
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spin_unlock(&dentry->d_lock);
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spin_unlock(&dcache_lock);
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dput(dentry);
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goto repeat;
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}
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spin_unlock(&dcache_lock);
|
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|
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/* adjust nlink and update timestamp */
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mutex_lock(&inode->i_mutex);
|
|
|
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inode->i_ctime = CURRENT_TIME;
|
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drop_nlink(inode);
|
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if (sysfs_type(sd) == SYSFS_DIR)
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drop_nlink(inode);
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|
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mutex_unlock(&inode->i_mutex);
|
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|
|
iput(inode);
|
|
}
|
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|
|
/**
|
|
* sysfs_addrm_finish - finish up sysfs_dirent add/remove
|
|
* @acxt: addrm context to finish up
|
|
*
|
|
* Finish up sysfs_dirent add/remove. Resources acquired by
|
|
* sysfs_addrm_start() are released and removed sysfs_dirents are
|
|
* cleaned up. Timestamps on the parent inode are updated.
|
|
*
|
|
* LOCKING:
|
|
* All mutexes acquired by sysfs_addrm_start() are released.
|
|
*/
|
|
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
|
|
{
|
|
/* release resources acquired by sysfs_addrm_start() */
|
|
mutex_unlock(&sysfs_mutex);
|
|
if (acxt->parent_inode) {
|
|
struct inode *inode = acxt->parent_inode;
|
|
|
|
/* if added/removed, update timestamps on the parent */
|
|
if (acxt->cnt)
|
|
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
|
|
|
|
mutex_unlock(&inode->i_mutex);
|
|
iput(inode);
|
|
}
|
|
|
|
/* kill removed sysfs_dirents */
|
|
while (acxt->removed) {
|
|
struct sysfs_dirent *sd = acxt->removed;
|
|
|
|
acxt->removed = sd->s_sibling;
|
|
sd->s_sibling = NULL;
|
|
|
|
sysfs_drop_dentry(sd);
|
|
sysfs_deactivate(sd);
|
|
sysfs_put(sd);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* sysfs_find_dirent - find sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd.
|
|
*
|
|
* LOCKING:
|
|
* mutex_lock(sysfs_mutex)
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
|
|
if (!strcmp(sd->s_name, name))
|
|
return sd;
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_dirent - find and get sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd and get
|
|
* it if found.
|
|
*
|
|
* LOCKING:
|
|
* Kernel thread context (may sleep). Grabs sysfs_mutex.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sd = sysfs_find_dirent(parent_sd, name);
|
|
sysfs_get(sd);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
return sd;
|
|
}
|
|
|
|
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
|
|
const char *name, struct sysfs_dirent **p_sd)
|
|
{
|
|
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
int rc;
|
|
|
|
/* allocate */
|
|
sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
|
|
if (!sd)
|
|
return -ENOMEM;
|
|
sd->s_dir.kobj = kobj;
|
|
|
|
/* link in */
|
|
sysfs_addrm_start(&acxt, parent_sd);
|
|
rc = sysfs_add_one(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (rc == 0)
|
|
*p_sd = sd;
|
|
else
|
|
sysfs_put(sd);
|
|
|
|
return rc;
|
|
}
|
|
|
|
int sysfs_create_subdir(struct kobject *kobj, const char *name,
|
|
struct sysfs_dirent **p_sd)
|
|
{
|
|
return create_dir(kobj, kobj->sd, name, p_sd);
|
|
}
|
|
|
|
/**
|
|
* sysfs_create_dir - create a directory for an object.
|
|
* @kobj: object we're creating directory for.
|
|
*/
|
|
int sysfs_create_dir(struct kobject * kobj)
|
|
{
|
|
struct sysfs_dirent *parent_sd, *sd;
|
|
int error = 0;
|
|
|
|
BUG_ON(!kobj);
|
|
|
|
if (kobj->parent)
|
|
parent_sd = kobj->parent->sd;
|
|
else
|
|
parent_sd = &sysfs_root;
|
|
|
|
error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd);
|
|
if (!error)
|
|
kobj->sd = sd;
|
|
return error;
|
|
}
|
|
|
|
static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
|
|
struct nameidata *nd)
|
|
{
|
|
struct dentry *ret = NULL;
|
|
struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
|
|
struct sysfs_dirent *sd;
|
|
struct inode *inode;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
|
|
|
|
/* no such entry */
|
|
if (!sd) {
|
|
ret = ERR_PTR(-ENOENT);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* attach dentry and inode */
|
|
inode = sysfs_get_inode(sd);
|
|
if (!inode) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* instantiate and hash dentry */
|
|
dentry->d_op = &sysfs_dentry_ops;
|
|
dentry->d_fsdata = sysfs_get(sd);
|
|
d_instantiate(dentry, inode);
|
|
d_rehash(dentry);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return ret;
|
|
}
|
|
|
|
const struct inode_operations sysfs_dir_inode_operations = {
|
|
.lookup = sysfs_lookup,
|
|
.setattr = sysfs_setattr,
|
|
};
|
|
|
|
static void remove_dir(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
|
|
sysfs_addrm_start(&acxt, sd->s_parent);
|
|
sysfs_remove_one(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
}
|
|
|
|
void sysfs_remove_subdir(struct sysfs_dirent *sd)
|
|
{
|
|
remove_dir(sd);
|
|
}
|
|
|
|
|
|
static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent **pos;
|
|
|
|
if (!dir_sd)
|
|
return;
|
|
|
|
pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
|
|
sysfs_addrm_start(&acxt, dir_sd);
|
|
pos = &dir_sd->s_dir.children;
|
|
while (*pos) {
|
|
struct sysfs_dirent *sd = *pos;
|
|
|
|
if (sysfs_type(sd) != SYSFS_DIR)
|
|
sysfs_remove_one(&acxt, sd);
|
|
else
|
|
pos = &(*pos)->s_sibling;
|
|
}
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
remove_dir(dir_sd);
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_dir - remove an object's directory.
|
|
* @kobj: object.
|
|
*
|
|
* The only thing special about this is that we remove any files in
|
|
* the directory before we remove the directory, and we've inlined
|
|
* what used to be sysfs_rmdir() below, instead of calling separately.
|
|
*/
|
|
|
|
void sysfs_remove_dir(struct kobject * kobj)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
|
|
spin_lock(&sysfs_assoc_lock);
|
|
kobj->sd = NULL;
|
|
spin_unlock(&sysfs_assoc_lock);
|
|
|
|
__sysfs_remove_dir(sd);
|
|
}
|
|
|
|
int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
struct dentry *parent = NULL;
|
|
struct dentry *old_dentry = NULL, *new_dentry = NULL;
|
|
const char *dup_name = NULL;
|
|
int error;
|
|
|
|
mutex_lock(&sysfs_rename_mutex);
|
|
|
|
error = 0;
|
|
if (strcmp(sd->s_name, new_name) == 0)
|
|
goto out; /* nothing to rename */
|
|
|
|
/* get the original dentry */
|
|
old_dentry = sysfs_get_dentry(sd);
|
|
if (IS_ERR(old_dentry)) {
|
|
error = PTR_ERR(old_dentry);
|
|
old_dentry = NULL;
|
|
goto out;
|
|
}
|
|
|
|
parent = old_dentry->d_parent;
|
|
|
|
/* lock parent and get dentry for new name */
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
error = -EEXIST;
|
|
if (sysfs_find_dirent(sd->s_parent, new_name))
|
|
goto out_unlock;
|
|
|
|
error = -ENOMEM;
|
|
new_dentry = d_alloc_name(parent, new_name);
|
|
if (!new_dentry)
|
|
goto out_unlock;
|
|
|
|
/* rename kobject and sysfs_dirent */
|
|
error = -ENOMEM;
|
|
new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
|
|
if (!new_name)
|
|
goto out_unlock;
|
|
|
|
error = kobject_set_name(kobj, "%s", new_name);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
dup_name = sd->s_name;
|
|
sd->s_name = new_name;
|
|
|
|
/* rename */
|
|
d_add(new_dentry, NULL);
|
|
d_move(old_dentry, new_dentry);
|
|
|
|
error = 0;
|
|
out_unlock:
|
|
mutex_unlock(&sysfs_mutex);
|
|
mutex_unlock(&parent->d_inode->i_mutex);
|
|
kfree(dup_name);
|
|
dput(old_dentry);
|
|
dput(new_dentry);
|
|
out:
|
|
mutex_unlock(&sysfs_rename_mutex);
|
|
return error;
|
|
}
|
|
|
|
int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
struct sysfs_dirent *new_parent_sd;
|
|
struct dentry *old_parent, *new_parent = NULL;
|
|
struct dentry *old_dentry = NULL, *new_dentry = NULL;
|
|
int error;
|
|
|
|
mutex_lock(&sysfs_rename_mutex);
|
|
BUG_ON(!sd->s_parent);
|
|
new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
|
|
|
|
error = 0;
|
|
if (sd->s_parent == new_parent_sd)
|
|
goto out; /* nothing to move */
|
|
|
|
/* get dentries */
|
|
old_dentry = sysfs_get_dentry(sd);
|
|
if (IS_ERR(old_dentry)) {
|
|
error = PTR_ERR(old_dentry);
|
|
old_dentry = NULL;
|
|
goto out;
|
|
}
|
|
old_parent = old_dentry->d_parent;
|
|
|
|
new_parent = sysfs_get_dentry(new_parent_sd);
|
|
if (IS_ERR(new_parent)) {
|
|
error = PTR_ERR(new_parent);
|
|
new_parent = NULL;
|
|
goto out;
|
|
}
|
|
|
|
again:
|
|
mutex_lock(&old_parent->d_inode->i_mutex);
|
|
if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
|
|
mutex_unlock(&old_parent->d_inode->i_mutex);
|
|
goto again;
|
|
}
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
error = -EEXIST;
|
|
if (sysfs_find_dirent(new_parent_sd, sd->s_name))
|
|
goto out_unlock;
|
|
|
|
error = -ENOMEM;
|
|
new_dentry = d_alloc_name(new_parent, sd->s_name);
|
|
if (!new_dentry)
|
|
goto out_unlock;
|
|
|
|
error = 0;
|
|
d_add(new_dentry, NULL);
|
|
d_move(old_dentry, new_dentry);
|
|
|
|
/* Remove from old parent's list and insert into new parent's list. */
|
|
sysfs_unlink_sibling(sd);
|
|
sysfs_get(new_parent_sd);
|
|
sysfs_put(sd->s_parent);
|
|
sd->s_parent = new_parent_sd;
|
|
sysfs_link_sibling(sd);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&sysfs_mutex);
|
|
mutex_unlock(&new_parent->d_inode->i_mutex);
|
|
mutex_unlock(&old_parent->d_inode->i_mutex);
|
|
out:
|
|
dput(new_parent);
|
|
dput(old_dentry);
|
|
dput(new_dentry);
|
|
mutex_unlock(&sysfs_rename_mutex);
|
|
return error;
|
|
}
|
|
|
|
/* Relationship between s_mode and the DT_xxx types */
|
|
static inline unsigned char dt_type(struct sysfs_dirent *sd)
|
|
{
|
|
return (sd->s_mode >> 12) & 15;
|
|
}
|
|
|
|
static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
|
|
{
|
|
struct dentry *dentry = filp->f_path.dentry;
|
|
struct sysfs_dirent * parent_sd = dentry->d_fsdata;
|
|
struct sysfs_dirent *pos;
|
|
ino_t ino;
|
|
|
|
if (filp->f_pos == 0) {
|
|
ino = parent_sd->s_ino;
|
|
if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
|
|
filp->f_pos++;
|
|
}
|
|
if (filp->f_pos == 1) {
|
|
if (parent_sd->s_parent)
|
|
ino = parent_sd->s_parent->s_ino;
|
|
else
|
|
ino = parent_sd->s_ino;
|
|
if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
|
|
filp->f_pos++;
|
|
}
|
|
if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
/* Skip the dentries we have already reported */
|
|
pos = parent_sd->s_dir.children;
|
|
while (pos && (filp->f_pos > pos->s_ino))
|
|
pos = pos->s_sibling;
|
|
|
|
for ( ; pos; pos = pos->s_sibling) {
|
|
const char * name;
|
|
int len;
|
|
|
|
name = pos->s_name;
|
|
len = strlen(name);
|
|
filp->f_pos = ino = pos->s_ino;
|
|
|
|
if (filldir(dirent, name, len, filp->f_pos, ino,
|
|
dt_type(pos)) < 0)
|
|
break;
|
|
}
|
|
if (!pos)
|
|
filp->f_pos = INT_MAX;
|
|
mutex_unlock(&sysfs_mutex);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
const struct file_operations sysfs_dir_operations = {
|
|
.read = generic_read_dir,
|
|
.readdir = sysfs_readdir,
|
|
};
|