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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2018 Red Hat, Inc.
*/
#include "libxfs_priv.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_trace.h"
#include "xfs_group.h"
/*
* Groups can have passive and active references.
*
* For passive references the code freeing a group is responsible for cleaning
* up objects that hold the passive references (e.g. cached buffers).
* Routines manipulating passive references are xfs_group_get, xfs_group_hold
* and xfs_group_put.
*
* Active references are for short term access to the group for walking trees or
* accessing state. If a group is being shrunk or offlined, the lookup will fail
* to find that group and return NULL instead.
* Routines manipulating active references are xfs_group_grab and
* xfs_group_rele.
*/
struct xfs_group *
xfs_group_get(
struct xfs_mount *mp,
uint32_t index,
enum xfs_group_type type)
{
struct xfs_group *xg;
rcu_read_lock();
xg = xa_load(&mp->m_groups[type].xa, index);
if (xg) {
trace_xfs_group_get(xg, _RET_IP_);
ASSERT(atomic_read(&xg->xg_ref) >= 0);
atomic_inc(&xg->xg_ref);
}
rcu_read_unlock();
return xg;
}
struct xfs_group *
xfs_group_hold(
struct xfs_group *xg)
{
ASSERT(atomic_read(&xg->xg_ref) > 0 ||
atomic_read(&xg->xg_active_ref) > 0);
trace_xfs_group_hold(xg, _RET_IP_);
atomic_inc(&xg->xg_ref);
return xg;
}
void
xfs_group_put(
struct xfs_group *xg)
{
trace_xfs_group_put(xg, _RET_IP_);
ASSERT(atomic_read(&xg->xg_ref) > 0);
atomic_dec(&xg->xg_ref);
}
struct xfs_group *
xfs_group_grab(
struct xfs_mount *mp,
uint32_t index,
enum xfs_group_type type)
{
struct xfs_group *xg;
rcu_read_lock();
xg = xa_load(&mp->m_groups[type].xa, index);
if (xg) {
trace_xfs_group_grab(xg, _RET_IP_);
if (!atomic_inc_not_zero(&xg->xg_active_ref))
xg = NULL;
}
rcu_read_unlock();
return xg;
}
/*
* Iterate to the next group. To start the iteration at @start_index, a %NULL
* @xg is passed, else the previous group returned from this function. The
* caller should break out of the loop when this returns %NULL. If the caller
* wants to break out of a loop that did not finish it needs to release the
* active reference to @xg using xfs_group_rele() itself.
*/
struct xfs_group *
xfs_group_next_range(
struct xfs_mount *mp,
struct xfs_group *xg,
uint32_t start_index,
uint32_t end_index,
enum xfs_group_type type)
{
uint32_t index = start_index;
if (xg) {
index = xg->xg_gno + 1;
xfs_group_rele(xg);
}
if (index > end_index)
return NULL;
return xfs_group_grab(mp, index, type);
}
/*
* Find the next group after @xg, or the first group if @xg is NULL.
*/
struct xfs_group *
xfs_group_grab_next_mark(
struct xfs_mount *mp,
struct xfs_group *xg,
xa_mark_t mark,
enum xfs_group_type type)
{
unsigned long index = 0;
if (xg) {
index = xg->xg_gno + 1;
xfs_group_rele(xg);
}
rcu_read_lock();
xg = xa_find(&mp->m_groups[type].xa, &index, ULONG_MAX, mark);
if (xg) {
trace_xfs_group_grab_next_tag(xg, _RET_IP_);
if (!atomic_inc_not_zero(&xg->xg_active_ref))
xg = NULL;
}
rcu_read_unlock();
return xg;
}
void
xfs_group_rele(
struct xfs_group *xg)
{
trace_xfs_group_rele(xg, _RET_IP_);
atomic_dec(&xg->xg_active_ref);
}
void
xfs_group_free(
struct xfs_mount *mp,
uint32_t index,
enum xfs_group_type type,
void (*uninit)(struct xfs_group *xg))
{
struct xfs_group *xg = xa_erase(&mp->m_groups[type].xa, index);
XFS_IS_CORRUPT(mp, atomic_read(&xg->xg_ref) != 0);
xfs_defer_drain_free(&xg->xg_intents_drain);
#ifdef __KERNEL__
if (xfs_group_has_extent_busy(xg->xg_mount, xg->xg_type))
kfree(xg->xg_busy_extents);
#endif
if (uninit)
uninit(xg);
/* drop the mount's active reference */
xfs_group_rele(xg);
XFS_IS_CORRUPT(mp, atomic_read(&xg->xg_active_ref) > 0);
XFS_IS_CORRUPT(mp, atomic_read(&xg->xg_active_ref) < 0);
kfree_rcu_mightsleep(xg);
}
int
xfs_group_insert(
struct xfs_mount *mp,
struct xfs_group *xg,
uint32_t index,
enum xfs_group_type type)
{
int error;
xg->xg_mount = mp;
xg->xg_gno = index;
xg->xg_type = type;
#ifdef __KERNEL__
if (xfs_group_has_extent_busy(mp, type)) {
xg->xg_busy_extents = xfs_extent_busy_alloc();
if (!xg->xg_busy_extents)
return -ENOMEM;
}
spin_lock_init(&xg->xg_state_lock);
xfs_hooks_init(&xg->xg_rmap_update_hooks);
#endif
xfs_defer_drain_init(&xg->xg_intents_drain);
/* Active ref owned by mount indicates group is online. */
atomic_set(&xg->xg_active_ref, 1);
error = xa_insert(&mp->m_groups[type].xa, index, xg, GFP_KERNEL);
if (error) {
WARN_ON_ONCE(error == -EBUSY);
goto out_drain;
}
return 0;
out_drain:
xfs_defer_drain_free(&xg->xg_intents_drain);
#ifdef __KERNEL__
if (xfs_group_has_extent_busy(xg->xg_mount, xg->xg_type))
kfree(xg->xg_busy_extents);
#endif
return error;
}
struct xfs_group *
xfs_group_get_by_fsb(
struct xfs_mount *mp,
xfs_fsblock_t fsbno,
enum xfs_group_type type)
{
return xfs_group_get(mp, xfs_fsb_to_gno(mp, fsbno, type), type);
}
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