mirror of
https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
synced 2026-10-28 10:41:38 -04:00
sysfs: Remove first pass at shadow directory support
While shadow directories appear to be a good idea, the current scheme
of controlling their creation and destruction outside of sysfs appears
to be a locking and maintenance nightmare in the face of sysfs
directories dynamically coming and going. Which can now occur for
directories containing network devices when CONFIG_SYSFS_DEPRECATED is
not set.
This patch removes everything from the initial shadow directory support
that allowed the shadow directory creation to be controlled at a higher
level. So except for a few bits of sysfs_rename_dir everything from
commit b592fcfe7f is now gone.
Signed-off-by: Eric W. Biederman <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Eric W. Biederman
Greg Kroah-Hartman
parent
869512ab5a
commit
90bc61359d
8 changed files with 33 additions and 229 deletions
167
fs/sysfs/dir.c
167
fs/sysfs/dir.c
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@ -569,9 +569,6 @@ static void sysfs_drop_dentry(struct sysfs_dirent *sd)
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spin_unlock(&dcache_lock);
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spin_unlock(&sysfs_assoc_lock);
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/* dentries for shadowed inodes are pinned, unpin */
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if (dentry && sysfs_is_shadowed_inode(dentry->d_inode))
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dput(dentry);
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dput(dentry);
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/* adjust nlink and update timestamp */
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@ -723,19 +720,15 @@ int sysfs_create_subdir(struct kobject *kobj, const char *name,
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/**
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* sysfs_create_dir - create a directory for an object.
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* @kobj: object we're creating directory for.
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* @shadow_parent: parent object.
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*/
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int sysfs_create_dir(struct kobject *kobj,
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struct sysfs_dirent *shadow_parent_sd)
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int sysfs_create_dir(struct kobject * kobj)
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{
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struct sysfs_dirent *parent_sd, *sd;
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int error = 0;
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BUG_ON(!kobj);
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if (shadow_parent_sd)
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parent_sd = shadow_parent_sd;
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else if (kobj->parent)
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if (kobj->parent)
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parent_sd = kobj->parent->sd;
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else if (sysfs_mount && sysfs_mount->mnt_sb)
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parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata;
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@ -890,45 +883,44 @@ void sysfs_remove_dir(struct kobject * kobj)
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__sysfs_remove_dir(sd);
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}
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int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
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const char *new_name)
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int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
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{
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struct sysfs_dirent *sd = kobj->sd;
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struct dentry *new_parent = NULL;
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struct sysfs_dirent *sd;
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struct dentry *parent = NULL;
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struct dentry *old_dentry = NULL, *new_dentry = NULL;
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struct sysfs_dirent *parent_sd;
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const char *dup_name = NULL;
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int error;
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if (!kobj->parent)
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return -EINVAL;
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/* get dentries */
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sd = kobj->sd;
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old_dentry = sysfs_get_dentry(sd);
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if (IS_ERR(old_dentry)) {
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error = PTR_ERR(old_dentry);
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goto out_dput;
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}
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new_parent = sysfs_get_dentry(new_parent_sd);
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if (IS_ERR(new_parent)) {
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error = PTR_ERR(new_parent);
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parent_sd = kobj->parent->sd;
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parent = sysfs_get_dentry(parent_sd);
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if (IS_ERR(parent)) {
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error = PTR_ERR(parent);
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goto out_dput;
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}
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/* lock new_parent and get dentry for new name */
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mutex_lock(&new_parent->d_inode->i_mutex);
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/* lock parent and get dentry for new name */
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mutex_lock(&parent->d_inode->i_mutex);
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new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
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new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
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if (IS_ERR(new_dentry)) {
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error = PTR_ERR(new_dentry);
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goto out_unlock;
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}
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/* By allowing two different directories with the same
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* d_parent we allow this routine to move between different
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* shadows of the same directory
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*/
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error = -EINVAL;
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if (old_dentry->d_parent->d_inode != new_parent->d_inode ||
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new_dentry->d_parent->d_inode != new_parent->d_inode ||
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old_dentry == new_dentry)
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if (old_dentry == new_dentry)
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goto out_unlock;
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error = -EEXIST;
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@ -955,9 +947,9 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
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d_move(sd->s_dentry, new_dentry);
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sysfs_unlink_sibling(sd);
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sysfs_get(new_parent_sd);
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sysfs_get(parent_sd);
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sysfs_put(sd->s_parent);
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sd->s_parent = new_parent_sd;
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sd->s_parent = parent_sd;
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sysfs_link_sibling(sd);
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mutex_unlock(&sysfs_mutex);
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@ -968,10 +960,10 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
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out_drop:
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d_drop(new_dentry);
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out_unlock:
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mutex_unlock(&new_parent->d_inode->i_mutex);
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mutex_unlock(&parent->d_inode->i_mutex);
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out_dput:
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kfree(dup_name);
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dput(new_parent);
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dput(parent);
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dput(old_dentry);
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dput(new_dentry);
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return error;
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@ -1192,121 +1184,6 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
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return offset;
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}
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/**
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* sysfs_make_shadowed_dir - Setup so a directory can be shadowed
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* @kobj: object we're creating shadow of.
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*/
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int sysfs_make_shadowed_dir(struct kobject *kobj,
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void * (*follow_link)(struct dentry *, struct nameidata *))
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{
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struct dentry *dentry;
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struct inode *inode;
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struct inode_operations *i_op;
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/* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */
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dentry = sysfs_get_dentry(kobj->sd);
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if (IS_ERR(dentry))
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return PTR_ERR(dentry);
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inode = dentry->d_inode;
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if (inode->i_op != &sysfs_dir_inode_operations) {
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dput(dentry);
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return -EINVAL;
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}
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i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
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if (!i_op)
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return -ENOMEM;
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memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
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i_op->follow_link = follow_link;
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/* Locking of inode->i_op?
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* Since setting i_op is a single word write and they
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* are atomic we should be ok here.
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*/
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inode->i_op = i_op;
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return 0;
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}
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/**
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* sysfs_create_shadow_dir - create a shadow directory for an object.
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* @kobj: object we're creating directory for.
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*
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* sysfs_make_shadowed_dir must already have been called on this
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* directory.
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*/
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struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj)
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{
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struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
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struct dentry *dir, *parent, *shadow;
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struct inode *inode;
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struct sysfs_dirent *sd;
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struct sysfs_addrm_cxt acxt;
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dir = sysfs_get_dentry(kobj->sd);
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if (IS_ERR(dir)) {
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sd = (void *)dir;
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goto out;
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}
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parent = dir->d_parent;
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inode = dir->d_inode;
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sd = ERR_PTR(-EINVAL);
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if (!sysfs_is_shadowed_inode(inode))
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goto out_dput;
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shadow = d_alloc(parent, &dir->d_name);
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if (!shadow)
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goto nomem;
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sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
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if (!sd)
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goto nomem;
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sd->s_elem.dir.kobj = kobj;
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sysfs_addrm_start(&acxt, parent_sd);
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/* add but don't link into children list */
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sysfs_add_one(&acxt, sd);
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/* attach and instantiate dentry */
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sysfs_attach_dentry(sd, shadow);
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d_instantiate(shadow, igrab(inode));
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inc_nlink(inode); /* tj: synchronization? */
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sysfs_addrm_finish(&acxt);
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dget(shadow); /* Extra count - pin the dentry in core */
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goto out_dput;
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nomem:
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dput(shadow);
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sd = ERR_PTR(-ENOMEM);
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out_dput:
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dput(dir);
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out:
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return sd;
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}
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/**
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* sysfs_remove_shadow_dir - remove an object's directory.
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* @shadow_sd: sysfs_dirent of shadow directory
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*
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* The only thing special about this is that we remove any files in
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* the directory before we remove the directory, and we've inlined
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* what used to be sysfs_rmdir() below, instead of calling separately.
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*/
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void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd)
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{
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__sysfs_remove_dir(shadow_sd);
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}
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const struct file_operations sysfs_dir_operations = {
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.open = sysfs_dir_open,
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.release = sysfs_dir_close,
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@ -13,7 +13,6 @@
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/err.h>
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#include <linux/fs.h>
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#include "sysfs.h"
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@ -33,16 +33,6 @@ static const struct inode_operations sysfs_inode_operations ={
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.setattr = sysfs_setattr,
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};
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void sysfs_delete_inode(struct inode *inode)
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{
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/* Free the shadowed directory inode operations */
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if (sysfs_is_shadowed_inode(inode)) {
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kfree(inode->i_op);
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inode->i_op = NULL;
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}
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return generic_delete_inode(inode);
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}
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int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
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{
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struct inode * inode = dentry->d_inode;
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@ -20,7 +20,7 @@ struct kmem_cache *sysfs_dir_cachep;
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static const struct super_operations sysfs_ops = {
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.statfs = simple_statfs,
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.drop_inode = sysfs_delete_inode,
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.drop_inode = generic_delete_inode,
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};
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struct sysfs_dirent sysfs_root = {
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@ -70,7 +70,6 @@ extern void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
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struct sysfs_dirent *sd);
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extern int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
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extern void sysfs_delete_inode(struct inode *inode);
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extern struct inode * sysfs_get_inode(struct sysfs_dirent *sd);
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extern void sysfs_instantiate(struct dentry *dentry, struct inode *inode);
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@ -121,8 +120,3 @@ static inline void sysfs_put(struct sysfs_dirent * sd)
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if (sd && atomic_dec_and_test(&sd->s_count))
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release_sysfs_dirent(sd);
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}
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static inline int sysfs_is_shadowed_inode(struct inode *inode)
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{
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return S_ISDIR(inode->i_mode) && inode->i_op->follow_link;
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}
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