[PATCH v2 10/21] btrfs: parameterize dev_extent_min

From: Naohiro Aota <naohiro.aota@wdc.com>
To: linux-btrfs@vger.kernel.org, David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	Nikolay Borisov <nborisov@suse.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
	Hannes Reinecke <hare@suse.com>,
	Anand Jain <anand.jain@oracle.com>,
	linux-fsdevel@vger.kernel.org,
	Naohiro Aota <naohiro.aota@wdc.com>
Subject: [PATCH v2 10/21] btrfs: parameterize dev_extent_min
Date: Wed, 12 Feb 2020 16:20:37 +0900	[thread overview]
Message-ID: <20200212072048.629856-11-naohiro.aota@wdc.com> (raw)
In-Reply-To: <20200212072048.629856-1-naohiro.aota@wdc.com>

Currently, we ignore a device whose available space is less than
"BTRFS_STRIPE_LEN * dev_stripes". This is a lower limit for current
allocation policy (to maximize the number of stripes). This commit
parameterizes dev_extent_min, so that other policies can set their own
lower limitation to ignore a device with an insufficient space.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/volumes.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3e2e3896d72a..38c2c425b997 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4836,6 +4836,7 @@ struct alloc_chunk_ctl {
 				   store parity information */
 	u64 max_stripe_size;
 	u64 max_chunk_size;
+	u64 dev_extent_min;
 	u64 stripe_size;
 	u64 chunk_size;
 	int ndevs;
@@ -4869,6 +4870,7 @@ init_alloc_chunk_ctl_policy_regular(struct btrfs_fs_devices *fs_devices,
 	/* We don't want a chunk larger than 10% of writable space */
 	ctl->max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
 				  ctl->max_chunk_size);
+	ctl->dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
 }
 
 static void init_alloc_chunk_ctl(struct btrfs_fs_devices *fs_devices,
@@ -4904,7 +4906,6 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
 	struct btrfs_device *device;
 	u64 total_avail;
 	u64 dev_extent_want = ctl->max_stripe_size * ctl->dev_stripes;
-	u64 dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
 	int ret;
 	int ndevs = 0;
 	u64 max_avail;
@@ -4932,7 +4933,7 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
 			total_avail = 0;
 
 		/* If there is no space on this device, skip it. */
-		if (total_avail == 0)
+		if (total_avail < ctl->dev_extent_min)
 			continue;
 
 		ret = find_free_dev_extent(device, dev_extent_want, &dev_offset,
@@ -4943,12 +4944,12 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
 		if (ret == 0)
 			max_avail = dev_extent_want;
 
-		if (max_avail < dev_extent_min) {
+		if (max_avail < ctl->dev_extent_min) {
 			if (btrfs_test_opt(info, ENOSPC_DEBUG))
 				btrfs_debug(info,
 			"%s: devid %llu has no free space, have=%llu want=%llu",
 					    __func__, device->devid, max_avail,
-					    dev_extent_min);
+					    ctl->dev_extent_min);
 			continue;
 		}
 
-- 
2.25.0

