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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 04/21] btrfs: refactor find_free_dev_extent_start()
Date: Wed, 12 Feb 2020 16:20:31 +0900
Message-ID: <20200212072048.629856-5-naohiro.aota@wdc.com> (raw)
In-Reply-To: <20200212072048.629856-1-naohiro.aota@wdc.com>

Factor out two functions from find_free_dev_extent_start().
dev_extent_search_start() decides the starting position of the search.
dev_extent_hole_check() checks if a hole found is suitable for device
extent allocation.

These functions also have the switch-cases to change the allocation
behavior depending on the policy.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/volumes.c | 80 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 60 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9fcbed9b57f9..5f4e875a42f6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1384,6 +1384,61 @@ static bool contains_pending_extent(struct btrfs_device *device, u64 *start,
 	return false;
 }
 
+static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
+{
+	switch (device->fs_devices->chunk_alloc_policy) {
+	case BTRFS_CHUNK_ALLOC_REGULAR:
+		/*
+		 * We don't want to overwrite the superblock on the
+		 * drive nor any area used by the boot loader (grub
+		 * for example), so we make sure to start at an offset
+		 * of at least 1MB.
+		 */
+		return max_t(u64, start, SZ_1M);
+	default:
+		BUG();
+	}
+}
+
+/**
+ * dev_extent_hole_check - check if specified hole is suitable for allocation
+ * @device:	the device which we have the hole
+ * @hole_start: starting position of the hole
+ * @hole_size:	the size of the hole
+ * @num_bytes:	the size of the free space that we need
+ *
+ * This function may modify @hole_start and @hole_end to reflect the
+ * suitable position for allocation. Returns 1 if hole position is
+ * updated, 0 otherwise.
+ */
+static bool dev_extent_hole_check(struct btrfs_device *device, u64 *hole_start,
+				  u64 *hole_size, u64 num_bytes)
+{
+	bool changed = false;
+	u64 hole_end = *hole_start + *hole_size;
+
+	/*
+	 * Have to check before we set max_hole_start, otherwise we
+	 * could end up sending back this offset anyway.
+	 */
+	if (contains_pending_extent(device, hole_start, *hole_size)) {
+		if (hole_end >= *hole_start)
+			*hole_size = hole_end - *hole_start;
+		else
+			*hole_size = 0;
+		changed = true;
+	}
+
+	switch (device->fs_devices->chunk_alloc_policy) {
+	case BTRFS_CHUNK_ALLOC_REGULAR:
+		/* No extra check */
+		break;
+	default:
+		BUG();
+	}
+
+	return changed;
+}
 
 /*
  * find_free_dev_extent_start - find free space in the specified device
@@ -1430,12 +1485,7 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 	int slot;
 	struct extent_buffer *l;
 
-	/*
-	 * We don't want to overwrite the superblock on the drive nor any area
-	 * used by the boot loader (grub for example), so we make sure to start
-	 * at an offset of at least 1MB.
-	 */
-	search_start = max_t(u64, search_start, SZ_1M);
+	search_start = dev_extent_search_start(device, search_start);
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -1493,18 +1543,8 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 
 		if (key.offset > search_start) {
 			hole_size = key.offset - search_start;
-
-			/*
-			 * Have to check before we set max_hole_start, otherwise
-			 * we could end up sending back this offset anyway.
-			 */
-			if (contains_pending_extent(device, &search_start,
-						    hole_size)) {
-				if (key.offset >= search_start)
-					hole_size = key.offset - search_start;
-				else
-					hole_size = 0;
-			}
+			dev_extent_hole_check(device, &search_start, &hole_size,
+					      num_bytes);
 
 			if (hole_size > max_hole_size) {
 				max_hole_start = search_start;
@@ -1543,8 +1583,8 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 	 */
 	if (search_end > search_start) {
 		hole_size = search_end - search_start;
-
-		if (contains_pending_extent(device, &search_start, hole_size)) {
+		if (dev_extent_hole_check(device, &search_start, &hole_size,
+					  num_bytes)) {
 			btrfs_release_path(path);
 			goto again;
 		}
-- 
2.25.0


  parent reply index

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12  7:20 [PATCH v2 00/21] btrfs: refactor and generalize chunk/dev_extent/extent allocation Naohiro Aota
2020-02-12  7:20 ` [PATCH v2 01/21] btrfs: change type of full_search to bool Naohiro Aota
2020-02-12  7:20 ` [PATCH v2 02/21] btrfs: do not BUG_ON with invalid profile Naohiro Aota
2020-02-12  7:58   ` Johannes Thumshirn
2020-02-12 14:14   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 03/21] btrfs: introduce chunk allocation policy Naohiro Aota
2020-02-12  7:20 ` Naohiro Aota [this message]
2020-02-12 14:16   ` [PATCH v2 04/21] btrfs: refactor find_free_dev_extent_start() Josef Bacik
2020-02-13 11:32   ` Johannes Thumshirn
2020-02-12  7:20 ` [PATCH v2 05/21] btrfs: introduce alloc_chunk_ctl Naohiro Aota
2020-02-12  8:00   ` Johannes Thumshirn
2020-02-13 16:17   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 06/21] btrfs: factor out init_alloc_chunk_ctl Naohiro Aota
2020-02-13 16:20   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 07/21] btrfs: factor out gather_device_info() Naohiro Aota
2020-02-12  8:04   ` Johannes Thumshirn
2020-02-12  7:20 ` [PATCH v2 08/21] btrfs: factor out decide_stripe_size() Naohiro Aota
2020-02-12  7:20 ` [PATCH v2 09/21] btrfs: factor out create_chunk() Naohiro Aota
2020-02-12  8:07   ` Johannes Thumshirn
2020-02-13 16:24   ` Josef Bacik
2020-02-20 10:17     ` Naohiro Aota
2020-02-12  7:20 ` [PATCH v2 10/21] btrfs: parameterize dev_extent_min Naohiro Aota
2020-02-13 16:27   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 11/21] btrfs: introduce extent allocation policy Naohiro Aota
2020-02-13 19:55   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 12/21] btrfs: move hint_byte into find_free_extent_ctl Naohiro Aota
2020-02-12 14:11   ` Johannes Thumshirn
2020-02-13 19:56   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 13/21] btrfs: move vairalbes for clustered allocation " Naohiro Aota
2020-02-12 14:14   ` Johannes Thumshirn
2020-02-13 19:57   ` Josef Bacik
2020-02-20 14:27   ` Christoph Hellwig
2020-02-12  7:20 ` [PATCH v2 14/21] btrfs: factor out do_allocation() Naohiro Aota
2020-02-12 14:45   ` Johannes Thumshirn
2020-02-13 19:57   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 15/21] btrfs: drop unnecessary arguments from clustered allocation functions Naohiro Aota
2020-02-12 14:47   ` Johannes Thumshirn
2020-02-13 19:58   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 16/21] btrfs: factor out release_block_group() Naohiro Aota
2020-02-12 14:48   ` Johannes Thumshirn
2020-02-13 19:58   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 17/21] btrfs: factor out found_extent() Naohiro Aota
2020-02-12 14:50   ` Johannes Thumshirn
2020-02-13 19:58   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 18/21] btrfs: drop unnecessary arguments from find_free_extent_update_loop() Naohiro Aota
2020-02-12 14:51   ` Johannes Thumshirn
2020-02-13 19:58   ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 19/21] btrfs: factor out chunk_allocation_failed() Naohiro Aota
2020-02-12 14:56   ` Johannes Thumshirn
2020-02-13 19:52   ` Josef Bacik
2020-02-20  9:57     ` Naohiro Aota
2020-02-12  7:20 ` [PATCH v2 20/21] btrfs: skip LOOP_NO_EMPTY_SIZE if not clustered allocation Naohiro Aota
2020-02-13 19:55   ` Josef Bacik
2020-02-20  9:56     ` Naohiro Aota
2020-02-20 15:40       ` Josef Bacik
2020-02-12  7:20 ` [PATCH v2 21/21] btrfs: factor out prepare_allocation() Naohiro Aota
2020-02-13 19:59   ` Josef Bacik

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