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-rw-r--r--module/zfs/arc.c47
1 files changed, 34 insertions, 13 deletions
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 5d5bcbe2b..16d970672 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -5789,8 +5789,8 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
boolean_t *headroom_boost)
{
arc_buf_hdr_t *hdr, *hdr_prev, *head;
- uint64_t write_asize, write_psize, write_sz, headroom,
- buf_compress_minsz;
+ uint64_t write_asize, write_sz, headroom, buf_compress_minsz,
+ stats_size;
void *buf_data;
boolean_t full;
l2arc_write_callback_t *cb;
@@ -5805,7 +5805,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
*headroom_boost = B_FALSE;
pio = NULL;
- write_sz = write_asize = write_psize = 0;
+ write_sz = write_asize = 0;
full = B_FALSE;
head = kmem_cache_alloc(hdr_l2only_cache, KM_PUSHPAGE);
head->b_flags |= ARC_FLAG_L2_WRITE_HEAD;
@@ -5842,6 +5842,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
for (; hdr; hdr = hdr_prev) {
kmutex_t *hash_lock;
uint64_t buf_sz;
+ uint64_t buf_a_sz;
if (arc_warm == B_FALSE)
hdr_prev = multilist_sublist_next(mls, hdr);
@@ -5870,7 +5871,15 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
continue;
}
- if ((write_sz + hdr->b_size) > target_sz) {
+ /*
+ * Assume that the buffer is not going to be compressed
+ * and could take more space on disk because of a larger
+ * disk block size.
+ */
+ buf_sz = hdr->b_size;
+ buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
+
+ if ((write_asize + buf_a_sz) > target_sz) {
full = B_TRUE;
mutex_exit(hash_lock);
break;
@@ -5935,8 +5944,6 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
* using it to denote the header's state change.
*/
hdr->b_l2hdr.b_daddr = L2ARC_ADDR_UNSET;
-
- buf_sz = hdr->b_size;
hdr->b_flags |= ARC_FLAG_HAS_L2HDR;
mutex_enter(&dev->l2ad_mtx);
@@ -5953,6 +5960,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
mutex_exit(hash_lock);
write_sz += buf_sz;
+ write_asize += buf_a_sz;
}
multilist_sublist_unlock(mls);
@@ -5972,6 +5980,19 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
mutex_enter(&dev->l2ad_mtx);
/*
+ * Note that elsewhere in this file arcstat_l2_asize
+ * and the used space on l2ad_vdev are updated using b_asize,
+ * which is not necessarily rounded up to the device block size.
+ * Too keep accounting consistent we do the same here as well:
+ * stats_size accumulates the sum of b_asize of the written buffers,
+ * while write_asize accumulates the sum of b_asize rounded up
+ * to the device block size.
+ * The latter sum is used only to validate the corectness of the code.
+ */
+ stats_size = 0;
+ write_asize = 0;
+
+ /*
* Now start writing the buffers. We're starting at the write head
* and work backwards, retracing the course of the buffer selector
* loop above.
@@ -6024,7 +6045,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
/* Compression may have squashed the buffer to zero length. */
if (buf_sz != 0) {
- uint64_t buf_p_sz;
+ uint64_t buf_a_sz;
wzio = zio_write_phys(pio, dev->l2ad_vdev,
dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF,
@@ -6035,14 +6056,14 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
zio_t *, wzio);
(void) zio_nowait(wzio);
- write_asize += buf_sz;
+ stats_size += buf_sz;
/*
* Keep the clock hand suitably device-aligned.
*/
- buf_p_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
- write_psize += buf_p_sz;
- dev->l2ad_hand += buf_p_sz;
+ buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
+ write_asize += buf_a_sz;
+ dev->l2ad_hand += buf_a_sz;
}
}
@@ -6052,8 +6073,8 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
ARCSTAT_BUMP(arcstat_l2_writes_sent);
ARCSTAT_INCR(arcstat_l2_write_bytes, write_asize);
ARCSTAT_INCR(arcstat_l2_size, write_sz);
- ARCSTAT_INCR(arcstat_l2_asize, write_asize);
- vdev_space_update(dev->l2ad_vdev, write_asize, 0, 0);
+ ARCSTAT_INCR(arcstat_l2_asize, stats_size);
+ vdev_space_update(dev->l2ad_vdev, stats_size, 0, 0);
/*
* Bump device hand to the device start if it is approaching the end.