Factor out decide_stripe_size() from __btrfs_alloc_chunk(). This function
calculates the actual stripe size to allocate. decide_stripe_size() handles
the common case to round down the 'ndevs' to 'devs_increment' and check the
upper and lower limitation of 'ndevs'. decide_stripe_size_regular() decides
the size of a stripe and the size of a chunk. The policy is to maximize the
number of stripes.
This commit has no functional changes.
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/volumes.c | 137 ++++++++++++++++++++++++++-------------------
1 file changed, 80 insertions(+), 57 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 02bd86d126ff..85c01df26852 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4973,6 +4973,84 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
return 0;
}
+static int decide_stripe_size_regular(struct alloc_chunk_ctl *ctl,
+ struct btrfs_device_info *devices_info)
+{
+ int data_stripes; /* number of stripes that count for
+ block group size */
+
+ /*
+ * The primary goal is to maximize the number of stripes, so use as
+ * many devices as possible, even if the stripes are not maximum sized.
+ *
+ * The DUP profile stores more than one stripe per device, the
+ * max_avail is the total size so we have to adjust.
+ */
+ ctl->stripe_size = div_u64(devices_info[ctl->ndevs - 1].max_avail,
+ ctl->dev_stripes);
+ ctl->num_stripes = ctl->ndevs * ctl->dev_stripes;
+
+ /*
+ * this will have to be fixed for RAID1 and RAID10 over
+ * more drives
+ */
+ data_stripes = (ctl->num_stripes - ctl->nparity) / ctl->ncopies;
+
+ /*
+ * Use the number of data stripes to figure out how big this chunk
+ * is really going to be in terms of logical address space,
+ * and compare that answer with the max chunk size. If it's higher,
+ * we try to reduce stripe_size.
+ */
+ if (ctl->stripe_size * data_stripes > ctl->max_chunk_size) {
+ /*
+ * Reduce stripe_size, round it up to a 16MB boundary again and
+ * then use it, unless it ends up being even bigger than the
+ * previous value we had already.
+ */
+ ctl->stripe_size = min(round_up(div_u64(ctl->max_chunk_size,
+ data_stripes), SZ_16M),
+ ctl->stripe_size);
+ }
+
+ /* align to BTRFS_STRIPE_LEN */
+ ctl->stripe_size = round_down(ctl->stripe_size, BTRFS_STRIPE_LEN);
+ ctl->chunk_size = ctl->stripe_size * data_stripes;
+
+ return 0;
+}
+
+static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
+ struct alloc_chunk_ctl *ctl,
+ struct btrfs_device_info *devices_info)
+{
+ struct btrfs_fs_info *info = fs_devices->fs_info;
+
+ /*
+ * Round down to number of usable stripes, devs_increment can be any
+ * number so we can't use round_down()
+ */
+ ctl->ndevs -= ctl->ndevs % ctl->devs_increment;
+
+ if (ctl->ndevs < ctl->devs_min) {
+ if (btrfs_test_opt(info, ENOSPC_DEBUG)) {
+ btrfs_debug(info,
+ "%s: not enough devices with free space: have=%d minimum required=%d",
+ __func__, ctl->ndevs, ctl->devs_min);
+ }
+ return -ENOSPC;
+ }
+
+ ctl->ndevs = min(ctl->ndevs, ctl->devs_max);
+
+ switch (fs_devices->chunk_alloc_policy) {
+ case BTRFS_CHUNK_ALLOC_REGULAR:
+ return decide_stripe_size_regular(ctl, devices_info);
+ default:
+ BUG();
+ }
+}
+
static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
u64 start, u64 type)
{
@@ -4983,8 +5061,6 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
struct extent_map *em;
struct btrfs_device_info *devices_info = NULL;
struct alloc_chunk_ctl ctl;
- int data_stripes; /* number of stripes that count for
- block group size */
int ret;
int i;
int j;
@@ -5015,60 +5091,9 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
if (ret < 0)
goto error;
- /*
- * Round down to number of usable stripes, devs_increment can be any
- * number so we can't use round_down()
- */
- ctl.ndevs -= ctl.ndevs % ctl.devs_increment;
-
- if (ctl.ndevs < ctl.devs_min) {
- ret = -ENOSPC;
- if (btrfs_test_opt(info, ENOSPC_DEBUG)) {
- btrfs_debug(info,
- "%s: not enough devices with free space: have=%d minimum required=%d",
- __func__, ctl.ndevs, ctl.devs_min);
- }
+ ret = decide_stripe_size(fs_devices, &ctl, devices_info);
+ if (ret < 0)
goto error;
- }
-
- ctl.ndevs = min(ctl.ndevs, ctl.devs_max);
-
- /*
- * The primary goal is to maximize the number of stripes, so use as
- * many devices as possible, even if the stripes are not maximum sized.
- *
- * The DUP profile stores more than one stripe per device, the
- * max_avail is the total size so we have to adjust.
- */
- ctl.stripe_size = div_u64(devices_info[ctl.ndevs - 1].max_avail,
- ctl.dev_stripes);
- ctl.num_stripes = ctl.ndevs * ctl.dev_stripes;
-
- /*
- * this will have to be fixed for RAID1 and RAID10 over
- * more drives
- */
- data_stripes = (ctl.num_stripes - ctl.nparity) / ctl.ncopies;
-
- /*
- * Use the number of data stripes to figure out how big this chunk
- * is really going to be in terms of logical address space,
- * and compare that answer with the max chunk size. If it's higher,
- * we try to reduce stripe_size.
- */
- if (ctl.stripe_size * data_stripes > ctl.max_chunk_size) {
- /*
- * Reduce stripe_size, round it up to a 16MB boundary again and
- * then use it, unless it ends up being even bigger than the
- * previous value we had already.
- */
- ctl.stripe_size = min(round_up(div_u64(ctl.max_chunk_size,
- data_stripes), SZ_16M),
- ctl.stripe_size);
- }
-
- /* align to BTRFS_STRIPE_LEN */
- ctl.stripe_size = round_down(ctl.stripe_size, BTRFS_STRIPE_LEN);
map = kmalloc(map_lookup_size(ctl.num_stripes), GFP_NOFS);
if (!map) {
@@ -5091,8 +5116,6 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
map->type = type;
map->sub_stripes = ctl.sub_stripes;
- ctl.chunk_size = ctl.stripe_size * data_stripes;
-
trace_btrfs_chunk_alloc(info, map, start, ctl.chunk_size);
em = alloc_extent_map();
--
2.25.0
