summaryrefslogtreecommitdiff
path: root/fs
diff options
context:
space:
mode:
authorMarcos Paulo de Souza <mpdesouza@suse.com>2020-08-21 17:54:44 +0300
committerDavid Sterba <dsterba@suse.com>2020-08-27 14:37:54 +0300
commite3e39c72b99f93bbd0420d38c858e7c4a061bb63 (patch)
treecf500248ff53d9145c4a7f752720cdd3cc863a3d /fs
parenta84d5d429f9eb56f81b388609841ed993f0ddfca (diff)
downloadlinux-e3e39c72b99f93bbd0420d38c858e7c4a061bb63.tar.xz
btrfs: block-group: fix free-space bitmap threshold
[BUG] After commit 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item"), cache->length is being assigned after calling btrfs_create_block_group_cache. This causes a problem since set_free_space_tree_thresholds calculates the free-space threshold to decide if the free-space tree should convert from extents to bitmaps. The current code calls set_free_space_tree_thresholds with cache->length being 0, which then makes cache->bitmap_high_thresh zero. This implies the system will always use bitmap instead of extents, which is not desired if the block group is not fragmented. This behavior can be seen by a test that expects to repair systems with FREE_SPACE_EXTENT and FREE_SPACE_BITMAP, but the current code only created FREE_SPACE_BITMAP. [FIX] Call set_free_space_tree_thresholds after setting cache->length. There is now a WARN_ON in set_free_space_tree_thresholds to help preventing the same mistake to happen again in the future. Link: https://github.com/kdave/btrfs-progs/issues/251 Fixes: 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item") CC: stable@vger.kernel.org # 5.8+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/block-group.c4
-rw-r--r--fs/btrfs/free-space-tree.c4
2 files changed, 7 insertions, 1 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 613920c17ac1..ea8aaf36647e 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1798,7 +1798,6 @@ static struct btrfs_block_group *btrfs_create_block_group_cache(
cache->fs_info = fs_info;
cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
- set_free_space_tree_thresholds(cache);
cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
@@ -1912,6 +1911,8 @@ static int read_one_block_group(struct btrfs_fs_info *info,
if (ret < 0)
goto error;
+ set_free_space_tree_thresholds(cache);
+
if (need_clear) {
/*
* When we mount with old space cache, we need to
@@ -2132,6 +2133,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
return -ENOMEM;
cache->length = size;
+ set_free_space_tree_thresholds(cache);
cache->used = bytes_used;
cache->flags = type;
cache->last_byte_to_unpin = (u64)-1;
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index 8b1f5c8897b7..6b9faf3b0e96 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -22,6 +22,10 @@ void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
size_t bitmap_size;
u64 num_bitmaps, total_bitmap_size;
+ if (WARN_ON(cache->length == 0))
+ btrfs_warn(cache->fs_info, "block group %llu length is zero",
+ cache->start);
+
/*
* We convert to bitmaps when the disk space required for using extents
* exceeds that required for using bitmaps.