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@xxxxxxx>
---
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 beee9a94142f..9bb673df777a 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 int dev_extent_hole_check(struct btrfs_device *device, u64 *hole_start,
+ u64 *hole_size, u64 num_bytes)
+{
+ int ret = 0;
+ 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;
+ ret = 1;
+ }
+
+ switch (device->fs_devices->chunk_alloc_policy) {
+ case BTRFS_CHUNK_ALLOC_REGULAR:
+ /* No extra check */
+ break;
+ default:
+ BUG();
+ }
+
+ return ret;
+}
/*
* 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
