@@ -3277,6 +3277,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
u64 limit_data = bctl->data.limit;
u64 limit_meta = bctl->meta.limit;
u64 limit_sys = bctl->sys.limit;
+ int chunk_reserved = 0;
/* step one make some room on all the devices */
devices = &fs_info->fs_devices->devices;
@@ -3326,6 +3327,8 @@ again:
key.type = BTRFS_CHUNK_ITEM_KEY;
while (1) {
+ u64 chunk_type;
+
if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
atomic_read(&fs_info->balance_cancel_req)) {
ret = -ECANCELED;
@@ -3371,8 +3374,10 @@ again:
spin_unlock(&fs_info->balance_lock);
}
+ chunk_type = btrfs_chunk_type(leaf, chunk);
ret = should_balance_chunk(chunk_root, leaf, chunk,
found_key.offset);
+
btrfs_release_path(path);
if (!ret) {
mutex_unlock(&fs_info->delete_unused_bgs_mutex);
@@ -3387,6 +3392,25 @@ again:
goto loop;
}
+ if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) && !chunk_reserved) {
+ trans = btrfs_start_transaction(chunk_root, 0);
+ if (IS_ERR(trans)) {
+ mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+ ret = PTR_ERR(trans);
+ goto error;
+ }
+
+ ret = btrfs_force_chunk_alloc(trans, chunk_root,
+ BTRFS_BLOCK_GROUP_DATA);
+ if (ret < 0) {
+ mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+ goto error;
+ }
+
+ btrfs_end_transaction(trans, chunk_root);
+ chunk_reserved = 1;
+ }
+
ret = btrfs_relocate_chunk(chunk_root,
found_key.offset);
mutex_unlock(&fs_info->delete_unused_bgs_mutex);
Reproduce: (In integration-4.3 branch) TEST_DEV=(/dev/vdg /dev/vdh) TEST_DIR=/mnt/tmp umount "$TEST_DEV" >/dev/null mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}" mount -o nospace_cache "$TEST_DEV" "$TEST_DIR" btrfs balance start -dusage=0 $TEST_DIR btrfs filesystem usage $TEST_DIR dd if=/dev/zero of="$TEST_DIR"/file count=100 btrfs filesystem usage $TEST_DIR Result: We can see "no data chunk" in first "btrfs filesystem usage": # btrfs filesystem usage $TEST_DIR Overall: ... Metadata,single: Size:8.00MiB, Used:0.00B /dev/vdg 8.00MiB Metadata,RAID1: Size:122.88MiB, Used:112.00KiB /dev/vdg 122.88MiB /dev/vdh 122.88MiB System,single: Size:4.00MiB, Used:0.00B /dev/vdg 4.00MiB System,RAID1: Size:8.00MiB, Used:16.00KiB /dev/vdg 8.00MiB /dev/vdh 8.00MiB Unallocated: /dev/vdg 1.06GiB /dev/vdh 1.07GiB And "data chunks changed from raid1 to single" in second "btrfs filesystem usage": # btrfs filesystem usage $TEST_DIR Overall: ... Data,single: Size:256.00MiB, Used:0.00B /dev/vdh 256.00MiB Metadata,single: Size:8.00MiB, Used:0.00B /dev/vdg 8.00MiB Metadata,RAID1: Size:122.88MiB, Used:112.00KiB /dev/vdg 122.88MiB /dev/vdh 122.88MiB System,single: Size:4.00MiB, Used:0.00B /dev/vdg 4.00MiB System,RAID1: Size:8.00MiB, Used:16.00KiB /dev/vdg 8.00MiB /dev/vdh 8.00MiB Unallocated: /dev/vdg 1.06GiB /dev/vdh 841.92MiB Reason: btrfs balance delete last data chunk in case of no data in the filesystem, then we can see "no data chunk" by "fi usage" command. And when we do write operation to fs, the only available data profile is 0x0, result is all new chunks are allocated single type. Fix: Allocate a data chunk explicitly to ensure we don't lose the raid profile for data. Test: Test by above script, and confirmed the logic by debug output. Changelog v1->v2: 1: Update patch description of "Fix" field 2: Use BTRFS_BLOCK_GROUP_DATA for btrfs_force_chunk_alloc instead of 1 3: Only reserve chunk if balance data chunk. All suggested-by: Filipe Manana <fdmanana@gmail.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/volumes.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)