Skip to main content

Browse the archive

Revision 7bf811a595a895b7a886dcf218d0d34f97df76dc authored by Josef Bacik on 08 October 2013, 02:11:09 UTC, committed by Chris Mason on 11 October 2013, 01:27:56 UTC 
Btrfs: limit delalloc pages outside of find_delalloc_range
 
Liu fixed part of this problem and unfortunately I steered him in slightly the
wrong direction and so didn't completely fix the problem.  The problem is we
limit the size of the delalloc range we are looking for to max bytes and then we
try to lock that range.  If we fail to lock the pages in that range we will
shrink the max bytes to a single page and re loop.  However if our first page is
inside of the delalloc range then we will end up limiting the end of the range
to a period before our first page.  This is illustrated below

[0 -------- delalloc range --------- 256mb]
                                  [page]

So find_delalloc_range will return with delalloc_start as 0 and end as 128mb,
and then we will notice that delalloc_start < *start and adjust it up, but not
adjust delalloc_end up, so things go sideways.  To fix this we need to not limit
the max bytes in find_delalloc_range, but in find_lock_delalloc_range and that
way we don't end up with this confusion.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
1 parent 4871c15
Raw File
irq_work.h 
#ifndef _LINUX_IRQ_WORK_H
#define _LINUX_IRQ_WORK_H

#include <linux/llist.h>

/*
 * An entry can be in one of four states:
 *
 * free	     NULL, 0 -> {claimed}       : free to be used
 * claimed   NULL, 3 -> {pending}       : claimed to be enqueued
 * pending   next, 3 -> {busy}          : queued, pending callback
 * busy      NULL, 2 -> {free, claimed} : callback in progress, can be claimed
 */

#define IRQ_WORK_PENDING	1UL
#define IRQ_WORK_BUSY		2UL
#define IRQ_WORK_FLAGS		3UL
#define IRQ_WORK_LAZY		4UL /* Doesn't want IPI, wait for tick */

struct irq_work {
	unsigned long flags;
	struct llist_node llnode;
	void (*func)(struct irq_work *);
};

static inline
void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
{
	work->flags = 0;
	work->func = func;
}

void irq_work_queue(struct irq_work *work);
void irq_work_run(void);
void irq_work_sync(struct irq_work *work);

#ifdef CONFIG_IRQ_WORK
bool irq_work_needs_cpu(void);
#else
static inline bool irq_work_needs_cpu(void) { return false; }
#endif

#endif /* _LINUX_IRQ_WORK_H */
back to top