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lsblk: make devtree dependences more generic 

We also need reference from child to parent to implement multi-parent
view. This change allows to walk on tree in both directions.

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2018-10-23 14:04:55 +02:00
parent 94d4c2dca4
commit 0986f29a3f
2 changed files with 68 additions and 29 deletions
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86
misc-utils/lsblk-devtree.c
View File

@ -1,4 +1,21 @@
/*
* These functions implement tree of block devices. The devtree struct contains
* two basic lists:
*
* 1) devtree->devices -- This is simple list without any hierarchy. We use
* reference counting here.
*
* 2) devtree->roots -- The root nodes of the trees. The code does not use
* reference counting here due to complexity and it's unnecessary.
*
* Note that the same device maybe have more parents and more children. The
* device is allocated only once and shared within the tree. The dependence
* (devdep struct) contains reference to child as well as to parent and the
* dependence is reference by ls_childs from parent device and by ls_parents
* from child. (Yes, "childs" is used for children ;-)
*
* Copyright (C) 2018 Karel Zak <kzak@redhat.com>
*/
#include "lsblk.h"
#include "sysfs.h"
@ -24,7 +41,8 @@ struct lsblk_device *lsblk_new_device()
dev->removable = -1;
dev->discard_granularity = (uint64_t) -1;
INIT_LIST_HEAD(&dev->deps);
INIT_LIST_HEAD(&dev->childs);
INIT_LIST_HEAD(&dev->parents);
INIT_LIST_HEAD(&dev->ls_roots);
INIT_LIST_HEAD(&dev->ls_devices);
@ -38,15 +56,17 @@ void lsblk_ref_device(struct lsblk_device *dev)
dev->refcount++;
}
static int device_remove_dependence(struct lsblk_device *dev, struct lsblk_devdep *dep)
/* removes dependence from child as well as from parent */
static int remove_dependence(struct lsblk_devdep *dep)
{
if (!dev || !dep || list_empty(&dev->deps))
if (!dep)
return -EINVAL;
DBG(DEV, ul_debugobj(dev, " %s: deallocate dependence 0x%p [%s]", dev->name, dep, dep->child->name));
list_del_init(&dep->ls_deps);
lsblk_unref_device(dep->child);
DBG(DEP, ul_debugobj(dep, " dealloc"));
list_del_init(&dep->ls_childs);
list_del_init(&dep->ls_parents);
free(dep);
return 0;
}
@ -56,12 +76,22 @@ static int device_remove_dependences(struct lsblk_device *dev)
if (!dev)
return -EINVAL;
DBG(DEV, ul_debugobj(dev, "%s: remove all depencences", dev->name));
while (!list_empty(&dev->deps)) {
struct lsblk_devdep *dp = list_entry(dev->deps.next,
struct lsblk_devdep, ls_deps);
device_remove_dependence(dev, dp);
if (!list_empty(&dev->childs))
DBG(DEV, ul_debugobj(dev, " %s: remove all children deps", dev->name));
while (!list_empty(&dev->childs)) {
struct lsblk_devdep *dp = list_entry(dev->childs.next,
struct lsblk_devdep, ls_childs);
remove_dependence(dp);
}
if (!list_empty(&dev->parents))
DBG(DEV, ul_debugobj(dev, " %s: remove all parents deps", dev->name));
while (!list_empty(&dev->parents)) {
struct lsblk_devdep *dp = list_entry(dev->parents.next,
struct lsblk_devdep, ls_parents);
remove_dependence(dp);
}
return 0;
}
@ -71,14 +101,13 @@ void lsblk_unref_device(struct lsblk_device *dev)
return;
if (--dev->refcount <= 0) {
DBG(DEV, ul_debugobj(dev, "dealloc"));
DBG(DEV, ul_debugobj(dev, " freeing [%s] <<", dev->name));
device_remove_dependences(dev);
lsblk_device_free_properties(dev->properties);
lsblk_unref_device(dev->wholedisk);
free(dev->name);
free(dev->dm_name);
free(dev->filename);
free(dev->mountpoint);
@ -86,11 +115,13 @@ void lsblk_unref_device(struct lsblk_device *dev)
ul_unref_path(dev->sysfs);
DBG(DEV, ul_debugobj(dev, " >> dealloc [%s]", dev->name));
free(dev->name);
free(dev);
}
}
int lsblk_device_has_dependence(struct lsblk_device *dev, struct lsblk_device *child)
int lsblk_device_has_child(struct lsblk_device *dev, struct lsblk_device *child)
{
struct lsblk_device *x = NULL;
struct lsblk_iter itr;
@ -112,25 +143,28 @@ int lsblk_device_new_dependence(struct lsblk_device *parent, struct lsblk_device
if (!parent || !child)
return -EINVAL;
if (lsblk_device_has_dependence(parent, child))
if (lsblk_device_has_child(parent, child))
return 1;
dp = calloc(1, sizeof(*dp));
if (!dp)
return -ENOMEM;
INIT_LIST_HEAD(&dp->ls_deps);
INIT_LIST_HEAD(&dp->ls_childs);
INIT_LIST_HEAD(&dp->ls_parents);
lsblk_ref_device(child);
dp->child = child;
list_add_tail(&dp->ls_childs, &parent->childs);
dp->parent = parent;
list_add_tail(&dp->ls_parents, &parent->parents);
DBG(DEV, ul_debugobj(parent, "add dependence 0x%p [%s->%s]", dp, parent->name, child->name));
list_add_tail(&dp->ls_deps, &parent->deps);
return 0;
}
static int device_next_dependence(struct lsblk_device *dev,
static int device_next_child(struct lsblk_device *dev,
struct lsblk_iter *itr,
struct lsblk_devdep **dp)
{
@ -141,9 +175,9 @@ static int device_next_dependence(struct lsblk_device *dev,
*dp = NULL;
if (!itr->head)
LSBLK_ITER_INIT(itr, &dev->deps);
LSBLK_ITER_INIT(itr, &dev->childs);
if (itr->p != itr->head) {
LSBLK_ITER_ITERATE(itr, *dp, struct lsblk_devdep, ls_deps);
LSBLK_ITER_ITERATE(itr, *dp, struct lsblk_devdep, ls_childs);
rc = 0;
}
@ -155,7 +189,7 @@ int lsblk_device_next_child(struct lsblk_device *dev,
struct lsblk_device **child)
{
struct lsblk_devdep *dp = NULL;
int rc = device_next_dependence(dev, itr, &dp);
int rc = device_next_child(dev, itr, &dp);
if (!child)
return -EINVAL;
@ -334,13 +368,13 @@ static void device_dedup_dependencies(
lsblk_reset_iter(&itr, LSBLK_ITER_FORWARD);
while (device_next_dependence(dev, &itr, &dp) == 0) {
while (device_next_child(dev, &itr, &dp) == 0) {
struct lsblk_device *child = dp->child;
if (device_dedupkey_is_equal(child, pattern)) {
DBG(DEV, ul_debugobj(dev, "remove duplicate dependence: 0x%p [%s]",
dp->child, dp->child->name));
device_remove_dependence(dev, dp);
remove_dependence(dp);
} else
device_dedup_dependencies(child, pattern);
}

11
misc-utils/lsblk.h
View File

@ -21,6 +21,7 @@
#define LSBLK_DEBUG_FILTER (1 << 2)
#define LSBLK_DEBUG_DEV (1 << 3)
#define LSBLK_DEBUG_TREE (1 << 4)
#define LSBLK_DEBUG_DEP (1 << 5)
#define LSBLK_DEBUG_ALL 0xFFFF
UL_DEBUG_DECLARE_MASK(lsblk);
@ -75,14 +76,18 @@ struct lsblk_devprop {
* means we need to allocate list member rather than use @child directly.
*/
struct lsblk_devdep {
struct list_head ls_deps; /* item in parent->deps */
struct list_head ls_childs; /* item in parent->childs */
struct list_head ls_parents; /* item in child->parents */
struct lsblk_device *child;
struct lsblk_device *parent;
};
struct lsblk_device {
int refcount;
struct list_head deps; /* list with lsblk_devdep */
struct list_head childs; /* list with lsblk_devdep */
struct list_head parents;
struct list_head ls_roots; /* item in devtree->roots list */
struct list_head ls_devices; /* item in devtree->devices list */
@ -186,7 +191,7 @@ struct lsblk_device *lsblk_new_device(void);
void lsblk_ref_device(struct lsblk_device *dev);
void lsblk_unref_device(struct lsblk_device *dev);
int lsblk_device_new_dependence(struct lsblk_device *parent, struct lsblk_device *child);
int lsblk_device_has_dependence(struct lsblk_device *dev, struct lsblk_device *child);
int lsblk_device_has_child(struct lsblk_device *dev, struct lsblk_device *child);
int lsblk_device_next_child(struct lsblk_device *dev,
struct lsblk_iter *itr,
struct lsblk_device **child);