Revision 24a70313969fc3fc440216b40babdb42564acff3 authored by Chris Mason on 21 November 2011, 14:39:11 UTC, committed by Chris Mason on 21 November 2011, 19:57:33 UTC
The log replay code only partially loads block groups, since the block group caching code is able to detect and deal with extents the logging code has pinned down. While the logging code is pinning down block groups, there is a bogus WARN_ON we're hitting if the code wasn't able to find an extent in the cache. This commit removes the warning because it can happen any time there isn't a valid free space cache for that block group. Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent 4d479cf
blk-ioc.c
/*
* Functions related to io context handling
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/slab.h>
#include "blk.h"
/*
* For io context allocations
*/
static struct kmem_cache *iocontext_cachep;
static void cfq_dtor(struct io_context *ioc)
{
if (!hlist_empty(&ioc->cic_list)) {
struct cfq_io_context *cic;
cic = hlist_entry(ioc->cic_list.first, struct cfq_io_context,
cic_list);
cic->dtor(ioc);
}
}
/*
* IO Context helper functions. put_io_context() returns 1 if there are no
* more users of this io context, 0 otherwise.
*/
int put_io_context(struct io_context *ioc)
{
if (ioc == NULL)
return 1;
BUG_ON(atomic_long_read(&ioc->refcount) == 0);
if (atomic_long_dec_and_test(&ioc->refcount)) {
rcu_read_lock();
cfq_dtor(ioc);
rcu_read_unlock();
kmem_cache_free(iocontext_cachep, ioc);
return 1;
}
return 0;
}
EXPORT_SYMBOL(put_io_context);
static void cfq_exit(struct io_context *ioc)
{
rcu_read_lock();
if (!hlist_empty(&ioc->cic_list)) {
struct cfq_io_context *cic;
cic = hlist_entry(ioc->cic_list.first, struct cfq_io_context,
cic_list);
cic->exit(ioc);
}
rcu_read_unlock();
}
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
{
struct io_context *ioc;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
if (atomic_dec_and_test(&ioc->nr_tasks))
cfq_exit(ioc);
put_io_context(ioc);
}
struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
{
struct io_context *ioc;
ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
if (ioc) {
atomic_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1);
spin_lock_init(&ioc->lock);
ioc->ioprio_changed = 0;
ioc->ioprio = 0;
ioc->last_waited = 0; /* doesn't matter... */
ioc->nr_batch_requests = 0; /* because this is 0 */
INIT_RADIX_TREE(&ioc->radix_root, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ioc->cic_list);
ioc->ioc_data = NULL;
#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
ioc->cgroup_changed = 0;
#endif
}
return ioc;
}
/*
* If the current task has no IO context then create one and initialise it.
* Otherwise, return its existing IO context.
*
* This returned IO context doesn't have a specifically elevated refcount,
* but since the current task itself holds a reference, the context can be
* used in general code, so long as it stays within `current` context.
*/
struct io_context *current_io_context(gfp_t gfp_flags, int node)
{
struct task_struct *tsk = current;
struct io_context *ret;
ret = tsk->io_context;
if (likely(ret))
return ret;
ret = alloc_io_context(gfp_flags, node);
if (ret) {
/* make sure set_task_ioprio() sees the settings above */
smp_wmb();
tsk->io_context = ret;
}
return ret;
}
/*
* If the current task has no IO context then create one and initialise it.
* If it does have a context, take a ref on it.
*
* This is always called in the context of the task which submitted the I/O.
*/
struct io_context *get_io_context(gfp_t gfp_flags, int node)
{
struct io_context *ioc = NULL;
/*
* Check for unlikely race with exiting task. ioc ref count is
* zero when ioc is being detached.
*/
do {
ioc = current_io_context(gfp_flags, node);
if (unlikely(!ioc))
break;
} while (!atomic_long_inc_not_zero(&ioc->refcount));
return ioc;
}
EXPORT_SYMBOL(get_io_context);
static int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",
sizeof(struct io_context), 0, SLAB_PANIC, NULL);
return 0;
}
subsys_initcall(blk_ioc_init);
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