From aefbe9a633b50a6124dbeb33a5d4efcdc6de6c30 Mon Sep 17 00:00:00 2001 From: Zhao Lei Date: Tue, 29 Sep 2015 21:03:54 +0800 Subject: [PATCH] btrfs: Fix lost-data-profile caused by auto removing bg 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" umount "$TEST_DEV" mount -o nospace_cache "$TEST_DEV" "$TEST_DIR" btrfs filesystem usage $TEST_DIR We can see the data chunk changed from raid1 to single: # btrfs filesystem usage $TEST_DIR Data,single: Size:8.00MiB, Used:0.00B /dev/vdg 8.00MiB # Reason: When a empty filesystem mount with -o nospace_cache, the last data blockgroup will be auto-removed in umount. Then if we mount it again, there is no data chunk in the filesystem, so the only available data profile is 0x0, result is all new chunks are created as single type. Fix: Don't auto-delete last blockgroup for a raid type. Test: Test by above script, and confirmed the logic by debug output. Reviewed-by: Filipe Manana Signed-off-by: Zhao Lei Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 99a8e57da8a1..b77ffbc3a145 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10279,8 +10279,10 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) block_group = list_first_entry(&fs_info->unused_bgs, struct btrfs_block_group_cache, bg_list); - space_info = block_group->space_info; list_del_init(&block_group->bg_list); + + space_info = block_group->space_info; + if (ret || btrfs_mixed_space_info(space_info)) { btrfs_put_block_group(block_group); continue; @@ -10294,7 +10296,8 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) spin_lock(&block_group->lock); if (block_group->reserved || btrfs_block_group_used(&block_group->item) || - block_group->ro) { + block_group->ro || + list_is_singular(&block_group->list)) { /* * We want to bail if we made new allocations or have * outstanding allocations in this block group. We do -- 2.20.1