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Diffstat (limited to 'fs/configfs/dir.c')
-rw-r--r--fs/configfs/dir.c151
1 files changed, 110 insertions, 41 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index d7955dc56737..c2ef617d2f97 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -58,15 +58,13 @@ static void configfs_d_iput(struct dentry * dentry,
if (sd) {
/* Coordinate with configfs_readdir */
spin_lock(&configfs_dirent_lock);
- /* Coordinate with configfs_attach_attr where will increase
- * sd->s_count and update sd->s_dentry to new allocated one.
- * Only set sd->dentry to null when this dentry is the only
- * sd owner.
- * If not do so, configfs_d_iput may run just after
- * configfs_attach_attr and set sd->s_dentry to null
- * even it's still in use.
+ /*
+ * Set sd->s_dentry to null only when this dentry is the one
+ * that is going to be killed. Otherwise configfs_d_iput may
+ * run just after configfs_attach_attr and set sd->s_dentry to
+ * NULL even it's still in use.
*/
- if (atomic_read(&sd->s_count) <= 2)
+ if (sd->s_dentry == dentry)
sd->s_dentry = NULL;
spin_unlock(&configfs_dirent_lock);
@@ -166,11 +164,38 @@ configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
#endif /* CONFIG_LOCKDEP */
+static struct configfs_fragment *new_fragment(void)
+{
+ struct configfs_fragment *p;
+
+ p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL);
+ if (p) {
+ atomic_set(&p->frag_count, 1);
+ init_rwsem(&p->frag_sem);
+ p->frag_dead = false;
+ }
+ return p;
+}
+
+void put_fragment(struct configfs_fragment *frag)
+{
+ if (frag && atomic_dec_and_test(&frag->frag_count))
+ kfree(frag);
+}
+
+struct configfs_fragment *get_fragment(struct configfs_fragment *frag)
+{
+ if (likely(frag))
+ atomic_inc(&frag->frag_count);
+ return frag;
+}
+
/*
* Allocates a new configfs_dirent and links it to the parent configfs_dirent
*/
static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
- void *element, int type)
+ void *element, int type,
+ struct configfs_fragment *frag)
{
struct configfs_dirent * sd;
@@ -190,6 +215,7 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
kmem_cache_free(configfs_dir_cachep, sd);
return ERR_PTR(-ENOENT);
}
+ sd->s_frag = get_fragment(frag);
list_add(&sd->s_sibling, &parent_sd->s_children);
spin_unlock(&configfs_dirent_lock);
@@ -224,11 +250,11 @@ static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
int configfs_make_dirent(struct configfs_dirent * parent_sd,
struct dentry * dentry, void * element,
- umode_t mode, int type)
+ umode_t mode, int type, struct configfs_fragment *frag)
{
struct configfs_dirent * sd;
- sd = configfs_new_dirent(parent_sd, element, type);
+ sd = configfs_new_dirent(parent_sd, element, type, frag);
if (IS_ERR(sd))
return PTR_ERR(sd);
@@ -275,7 +301,8 @@ static void init_symlink(struct inode * inode)
* until it is validated by configfs_dir_set_ready()
*/
-static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
+static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
+ struct configfs_fragment *frag)
{
int error;
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
@@ -288,7 +315,8 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
return error;
error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
- CONFIGFS_DIR | CONFIGFS_USET_CREATING);
+ CONFIGFS_DIR | CONFIGFS_USET_CREATING,
+ frag);
if (unlikely(error))
return error;
@@ -353,9 +381,10 @@ int configfs_create_link(struct configfs_symlink *sl,
{
int err = 0;
umode_t mode = S_IFLNK | S_IRWXUGO;
+ struct configfs_dirent *p = parent->d_fsdata;
- err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
- CONFIGFS_ITEM_LINK);
+ err = configfs_make_dirent(p, dentry, sl, mode,
+ CONFIGFS_ITEM_LINK, p->s_frag);
if (!err) {
err = configfs_create(dentry, mode, init_symlink);
if (err) {
@@ -614,7 +643,8 @@ static int populate_attrs(struct config_item *item)
static int configfs_attach_group(struct config_item *parent_item,
struct config_item *item,
- struct dentry *dentry);
+ struct dentry *dentry,
+ struct configfs_fragment *frag);
static void configfs_detach_group(struct config_item *item);
static void detach_groups(struct config_group *group)
@@ -662,7 +692,8 @@ static void detach_groups(struct config_group *group)
* try using vfs_mkdir. Just a thought.
*/
static int create_default_group(struct config_group *parent_group,
- struct config_group *group)
+ struct config_group *group,
+ struct configfs_fragment *frag)
{
int ret;
struct configfs_dirent *sd;
@@ -678,7 +709,7 @@ static int create_default_group(struct config_group *parent_group,
d_add(child, NULL);
ret = configfs_attach_group(&parent_group->cg_item,
- &group->cg_item, child);
+ &group->cg_item, child, frag);
if (!ret) {
sd = child->d_fsdata;
sd->s_type |= CONFIGFS_USET_DEFAULT;
@@ -692,13 +723,14 @@ static int create_default_group(struct config_group *parent_group,
return ret;
}
-static int populate_groups(struct config_group *group)
+static int populate_groups(struct config_group *group,
+ struct configfs_fragment *frag)
{
struct config_group *new_group;
int ret = 0;
list_for_each_entry(new_group, &group->default_groups, group_entry) {
- ret = create_default_group(group, new_group);
+ ret = create_default_group(group, new_group, frag);
if (ret) {
detach_groups(group);
break;
@@ -812,11 +844,12 @@ static void link_group(struct config_group *parent_group, struct config_group *g
*/
static int configfs_attach_item(struct config_item *parent_item,
struct config_item *item,
- struct dentry *dentry)
+ struct dentry *dentry,
+ struct configfs_fragment *frag)
{
int ret;
- ret = configfs_create_dir(item, dentry);
+ ret = configfs_create_dir(item, dentry, frag);
if (!ret) {
ret = populate_attrs(item);
if (ret) {
@@ -846,12 +879,13 @@ static void configfs_detach_item(struct config_item *item)
static int configfs_attach_group(struct config_item *parent_item,
struct config_item *item,
- struct dentry *dentry)
+ struct dentry *dentry,
+ struct configfs_fragment *frag)
{
int ret;
struct configfs_dirent *sd;
- ret = configfs_attach_item(parent_item, item, dentry);
+ ret = configfs_attach_item(parent_item, item, dentry, frag);
if (!ret) {
sd = dentry->d_fsdata;
sd->s_type |= CONFIGFS_USET_DIR;
@@ -867,7 +901,7 @@ static int configfs_attach_group(struct config_item *parent_item,
*/
inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
configfs_adjust_dir_dirent_depth_before_populate(sd);
- ret = populate_groups(to_config_group(item));
+ ret = populate_groups(to_config_group(item), frag);
if (ret) {
configfs_detach_item(item);
d_inode(dentry)->i_flags |= S_DEAD;
@@ -1262,6 +1296,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
struct configfs_dirent *sd;
struct config_item_type *type;
struct module *subsys_owner = NULL, *new_item_owner = NULL;
+ struct configfs_fragment *frag;
char *name;
sd = dentry->d_parent->d_fsdata;
@@ -1280,6 +1315,12 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
goto out;
}
+ frag = new_fragment();
+ if (!frag) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
/* Get a working ref for the duration of this function */
parent_item = configfs_get_config_item(dentry->d_parent);
type = parent_item->ci_type;
@@ -1382,9 +1423,9 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
spin_unlock(&configfs_dirent_lock);
if (group)
- ret = configfs_attach_group(parent_item, item, dentry);
+ ret = configfs_attach_group(parent_item, item, dentry, frag);
else
- ret = configfs_attach_item(parent_item, item, dentry);
+ ret = configfs_attach_item(parent_item, item, dentry, frag);
spin_lock(&configfs_dirent_lock);
sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
@@ -1421,6 +1462,7 @@ out_put:
* reference.
*/
config_item_put(parent_item);
+ put_fragment(frag);
out:
return ret;
@@ -1432,6 +1474,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
struct config_item *item;
struct configfs_subsystem *subsys;
struct configfs_dirent *sd;
+ struct configfs_fragment *frag;
struct module *subsys_owner = NULL, *dead_item_owner = NULL;
int ret;
@@ -1489,6 +1532,16 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
}
} while (ret == -EAGAIN);
+ frag = sd->s_frag;
+ if (down_write_killable(&frag->frag_sem)) {
+ spin_lock(&configfs_dirent_lock);
+ configfs_detach_rollback(dentry);
+ spin_unlock(&configfs_dirent_lock);
+ return -EINTR;
+ }
+ frag->frag_dead = true;
+ up_write(&frag->frag_sem);
+
/* Get a working ref for the duration of this function */
item = configfs_get_config_item(dentry);
@@ -1589,7 +1642,7 @@ static int configfs_dir_open(struct inode *inode, struct file *file)
*/
err = -ENOENT;
if (configfs_dirent_is_ready(parent_sd)) {
- file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
+ file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL);
if (IS_ERR(file->private_data))
err = PTR_ERR(file->private_data);
else
@@ -1745,8 +1798,13 @@ int configfs_register_group(struct config_group *parent_group,
{
struct configfs_subsystem *subsys = parent_group->cg_subsys;
struct dentry *parent;
+ struct configfs_fragment *frag;
int ret;
+ frag = new_fragment();
+ if (!frag)
+ return -ENOMEM;
+
mutex_lock(&subsys->su_mutex);
link_group(parent_group, group);
mutex_unlock(&subsys->su_mutex);
@@ -1754,7 +1812,7 @@ int configfs_register_group(struct config_group *parent_group,
parent = parent_group->cg_item.ci_dentry;
inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
- ret = create_default_group(parent_group, group);
+ ret = create_default_group(parent_group, group, frag);
if (ret)
goto err_out;
@@ -1762,12 +1820,14 @@ int configfs_register_group(struct config_group *parent_group,
configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
spin_unlock(&configfs_dirent_lock);
inode_unlock(d_inode(parent));
+ put_fragment(frag);
return 0;
err_out:
inode_unlock(d_inode(parent));
mutex_lock(&subsys->su_mutex);
unlink_group(group);
mutex_unlock(&subsys->su_mutex);
+ put_fragment(frag);
return ret;
}
EXPORT_SYMBOL(configfs_register_group);
@@ -1783,16 +1843,12 @@ void configfs_unregister_group(struct config_group *group)
struct configfs_subsystem *subsys = group->cg_subsys;
struct dentry *dentry = group->cg_item.ci_dentry;
struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
+ struct configfs_dirent *sd = dentry->d_fsdata;
+ struct configfs_fragment *frag = sd->s_frag;
- mutex_lock(&subsys->su_mutex);
- if (!group->cg_item.ci_parent->ci_group) {
- /*
- * The parent has already been unlinked and detached
- * due to a rmdir.
- */
- goto unlink_group;
- }
- mutex_unlock(&subsys->su_mutex);
+ down_write(&frag->frag_sem);
+ frag->frag_dead = true;
+ up_write(&frag->frag_sem);
inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
spin_lock(&configfs_dirent_lock);
@@ -1808,7 +1864,6 @@ void configfs_unregister_group(struct config_group *group)
dput(dentry);
mutex_lock(&subsys->su_mutex);
-unlink_group:
unlink_group(group);
mutex_unlock(&subsys->su_mutex);
}
@@ -1865,10 +1920,17 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
struct dentry *dentry;
struct dentry *root;
struct configfs_dirent *sd;
+ struct configfs_fragment *frag;
+
+ frag = new_fragment();
+ if (!frag)
+ return -ENOMEM;
root = configfs_pin_fs();
- if (IS_ERR(root))
+ if (IS_ERR(root)) {
+ put_fragment(frag);
return PTR_ERR(root);
+ }
if (!group->cg_item.ci_name)
group->cg_item.ci_name = group->cg_item.ci_namebuf;
@@ -1884,7 +1946,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
d_add(dentry, NULL);
err = configfs_attach_group(sd->s_element, &group->cg_item,
- dentry);
+ dentry, frag);
if (err) {
BUG_ON(d_inode(dentry));
d_drop(dentry);
@@ -1902,6 +1964,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
unlink_group(group);
configfs_release_fs();
}
+ put_fragment(frag);
return err;
}
@@ -1911,12 +1974,18 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
struct config_group *group = &subsys->su_group;
struct dentry *dentry = group->cg_item.ci_dentry;
struct dentry *root = dentry->d_sb->s_root;
+ struct configfs_dirent *sd = dentry->d_fsdata;
+ struct configfs_fragment *frag = sd->s_frag;
if (dentry->d_parent != root) {
pr_err("Tried to unregister non-subsystem!\n");
return;
}
+ down_write(&frag->frag_sem);
+ frag->frag_dead = true;
+ up_write(&frag->frag_sem);
+
inode_lock_nested(d_inode(root),
I_MUTEX_PARENT);
inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);