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xfs: prevent unwritten extent conversion from blocking I/O completion

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Unwritten extent conversion can recurse back into the filesystem due
to memory allocation. Memory reclaim requires I/O completions to be
processed to allow the callers to make progress. If the I/O
completion workqueue thread is doing the recursion, then we have a
deadlock situation.

Move unwritten extent completion into it's own workqueue so it
doesn't block I/O completions for normal delayed allocation or
overwrite data.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Dave Chinner 2009-04-06 18:42:11 +02:00 committed by Christoph Hellwig
parent 705db3fd46
commit c626d174cf
3 changed files with 31 additions and 17 deletions
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38
fs/xfs/linux-2.6/xfs_aops.c
View File

@ -152,23 +152,6 @@ xfs_find_bdev_for_inode(
return mp->m_ddev_targp->bt_bdev; return mp->m_ddev_targp->bt_bdev;
} }
/*
* Schedule IO completion handling on a xfsdatad if this was
* the final hold on this ioend. If we are asked to wait,
* flush the workqueue.
*/
STATIC void
xfs_finish_ioend(
xfs_ioend_t *ioend,
int wait)
{
if (atomic_dec_and_test(&ioend->io_remaining)) {
queue_work(xfsdatad_workqueue, &ioend->io_work);
if (wait)
flush_workqueue(xfsdatad_workqueue);
}
}
/* /*
* We're now finished for good with this ioend structure. * We're now finished for good with this ioend structure.
* Update the page state via the associated buffer_heads, * Update the page state via the associated buffer_heads,
@ -309,6 +292,27 @@ xfs_end_bio_read(
xfs_destroy_ioend(ioend); xfs_destroy_ioend(ioend);
} }
/*
* Schedule IO completion handling on a xfsdatad if this was
* the final hold on this ioend. If we are asked to wait,
* flush the workqueue.
*/
STATIC void
xfs_finish_ioend(
xfs_ioend_t *ioend,
int wait)
{
if (atomic_dec_and_test(&ioend->io_remaining)) {
struct workqueue_struct *wq = xfsdatad_workqueue;
if (ioend->io_work.func == xfs_end_bio_unwritten)
wq = xfsconvertd_workqueue;
queue_work(wq, &ioend->io_work);
if (wait)
flush_workqueue(wq);
}
}
/* /*
* Allocate and initialise an IO completion structure. * Allocate and initialise an IO completion structure.
* We need to track unwritten extent write completion here initially. * We need to track unwritten extent write completion here initially.

1
fs/xfs/linux-2.6/xfs_aops.h
View File

@ -19,6 +19,7 @@
#define __XFS_AOPS_H__ #define __XFS_AOPS_H__
extern struct workqueue_struct *xfsdatad_workqueue; extern struct workqueue_struct *xfsdatad_workqueue;
extern struct workqueue_struct *xfsconvertd_workqueue;
extern mempool_t *xfs_ioend_pool; extern mempool_t *xfs_ioend_pool;
/* /*

9
fs/xfs/linux-2.6/xfs_buf.c
View File

@ -51,6 +51,7 @@ static struct shrinker xfs_buf_shake = {
static struct workqueue_struct *xfslogd_workqueue; static struct workqueue_struct *xfslogd_workqueue;
struct workqueue_struct *xfsdatad_workqueue; struct workqueue_struct *xfsdatad_workqueue;
struct workqueue_struct *xfsconvertd_workqueue;
#ifdef XFS_BUF_TRACE #ifdef XFS_BUF_TRACE
void void
@ -1775,6 +1776,7 @@ xfs_flush_buftarg(
xfs_buf_t *bp, *n; xfs_buf_t *bp, *n;
int pincount = 0; int pincount = 0;
xfs_buf_runall_queues(xfsconvertd_workqueue);
xfs_buf_runall_queues(xfsdatad_workqueue); xfs_buf_runall_queues(xfsdatad_workqueue);
xfs_buf_runall_queues(xfslogd_workqueue); xfs_buf_runall_queues(xfslogd_workqueue);
@ -1831,9 +1833,15 @@ xfs_buf_init(void)
if (!xfsdatad_workqueue) if (!xfsdatad_workqueue)
goto out_destroy_xfslogd_workqueue; goto out_destroy_xfslogd_workqueue;
xfsconvertd_workqueue = create_workqueue("xfsconvertd");
if (!xfsconvertd_workqueue)
goto out_destroy_xfsdatad_workqueue;
register_shrinker(&xfs_buf_shake); register_shrinker(&xfs_buf_shake);
return 0; return 0;
out_destroy_xfsdatad_workqueue:
destroy_workqueue(xfsdatad_workqueue);
out_destroy_xfslogd_workqueue: out_destroy_xfslogd_workqueue:
destroy_workqueue(xfslogd_workqueue); destroy_workqueue(xfslogd_workqueue);
out_free_buf_zone: out_free_buf_zone:
@ -1849,6 +1857,7 @@ void
xfs_buf_terminate(void) xfs_buf_terminate(void)
{ {
unregister_shrinker(&xfs_buf_shake); unregister_shrinker(&xfs_buf_shake);
destroy_workqueue(xfsconvertd_workqueue);
destroy_workqueue(xfsdatad_workqueue); destroy_workqueue(xfsdatad_workqueue);
destroy_workqueue(xfslogd_workqueue); destroy_workqueue(xfslogd_workqueue);
kmem_zone_destroy(xfs_buf_zone); kmem_zone_destroy(xfs_buf_zone);