Author: smh
Date: Thu Mar 21 10:16:10 2013
New Revision: 248574
URL: http://svnweb.freebsd.org/changeset/base/248574
Log:
Improve TXG handling in the TRIM module.
This patch adds some improvements to the way the trim module considers
TXGs:
- Free ZIOs are registered with the TXG from the ZIO itself, not the
current SPA syncing TXG (which may be out of date);
- L2ARC are registered with a zero TXG number, as L2ARC has no concept
of TXGs;
- The TXG limit for issuing TRIMs is now computed from the last synced
TXG, not the currently syncing TXG. Indeed, under extremely unlikely
race conditions, there is a risk we could trim blocks which have been
freed in a TXG that has not finished syncing, resulting in potential
data corruption in case of a crash.
Reviewed by: pjd (mentor)
Approved by: pjd (mentor)
Obtained from:
https://github.com/dechamps/zfs/commit/5b46ad40d9081d75505d6f3bf04ac652445df366
MFC after: 2 weeks
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Thu Mar 21
10:02:32 2013 (r248573)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Thu Mar 21
10:16:10 2013 (r248574)
@@ -1693,7 +1693,7 @@ arc_hdr_destroy(arc_buf_hdr_t *hdr)
if (l2hdr != NULL) {
trim_map_free(l2hdr->b_dev->l2ad_vdev, l2hdr->b_daddr,
- hdr->b_size);
+ hdr->b_size, 0);
list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size);
kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
@@ -3532,7 +3532,7 @@ arc_release(arc_buf_t *buf, void *tag)
if (l2hdr) {
trim_map_free(l2hdr->b_dev->l2ad_vdev, l2hdr->b_daddr,
- hdr->b_size);
+ hdr->b_size, 0);
list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
ARCSTAT_INCR(arcstat_l2_size, -buf_size);
@@ -4448,7 +4448,7 @@ l2arc_write_done(zio_t *zio)
abl2 = ab->b_l2hdr;
ab->b_l2hdr = NULL;
trim_map_free(abl2->b_dev->l2ad_vdev, abl2->b_daddr,
- ab->b_size);
+ ab->b_size, 0);
kmem_free(abl2, sizeof (l2arc_buf_hdr_t));
ARCSTAT_INCR(arcstat_l2_size, -ab->b_size);
}
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h Thu Mar
21 10:02:32 2013 (r248573)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h Thu Mar
21 10:16:10 2013 (r248574)
@@ -36,7 +36,7 @@ extern "C" {
extern void trim_map_create(vdev_t *vd);
extern void trim_map_destroy(vdev_t *vd);
-extern void trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size);
+extern void trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size, uint64_t
txg);
extern boolean_t trim_map_write_start(zio_t *zio);
extern void trim_map_write_done(zio_t *zio);
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c Thu Mar
21 10:02:32 2013 (r248573)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c Thu Mar
21 10:16:10 2013 (r248574)
@@ -272,7 +272,7 @@ trim_map_free_locked(trim_map_t *tm, uin
}
void
-trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size)
+trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size, uint64_t txg)
{
trim_map_t *tm = vd->vdev_trimmap;
@@ -280,8 +280,7 @@ trim_map_free(vdev_t *vd, uint64_t offse
return;
mutex_enter(&tm->tm_lock);
- trim_map_free_locked(tm, offset, TRIM_ZIO_END(vd, offset, size),
- vd->vdev_spa->spa_syncing_txg);
+ trim_map_free_locked(tm, offset, TRIM_ZIO_END(vd, offset, size), txg);
mutex_exit(&tm->tm_lock);
}
@@ -387,7 +386,7 @@ trim_map_vdev_commit(spa_t *spa, zio_t *
if (tm == NULL)
return;
- txglimit = MIN(spa->spa_syncing_txg, spa_freeze_txg(spa)) -
+ txglimit = MIN(spa_last_synced_txg(spa), spa_freeze_txg(spa)) -
trim_txg_limit;
mutex_enter(&tm->tm_lock);
@@ -444,7 +443,7 @@ trim_map_commit(spa_t *spa, zio_t *zio,
{
int c;
- if (vd == NULL || spa->spa_syncing_txg <= trim_txg_limit)
+ if (vd == NULL || spa_last_synced_txg(spa) <= trim_txg_limit)
return;
if (vd->vdev_ops->vdev_op_leaf) {
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Thu Mar 21
10:02:32 2013 (r248573)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Thu Mar 21
10:16:10 2013 (r248574)
@@ -2475,7 +2475,7 @@ zio_vdev_io_start(zio_t *zio)
}
if (vd->vdev_ops->vdev_op_leaf && zio->io_type == ZIO_TYPE_FREE) {
- trim_map_free(vd, zio->io_offset, zio->io_size);
+ trim_map_free(vd, zio->io_offset, zio->io_size, zio->io_txg);
return (ZIO_PIPELINE_CONTINUE);
}
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