btrfs: take overcommit into account in inc_block_group_ro
inc_block_group_ro does a calculation to see if we have enough room left
over if we mark this block group as read only in order to see if it's ok
to mark the block group as read only.
The problem is this calculation _only_ works for data, where our used is
always less than our total. For metadata we will overcommit, so this
will almost always fail for metadata.
Fix this by exporting btrfs_can_overcommit, and then see if we have
enough space to remove the remaining free space in the block group we
are trying to mark read only. If we do then we can mark this block
group as read only.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index c12e91b..404e050 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1191,7 +1191,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
- u64 sinfo_used;
int ret = -ENOSPC;
spin_lock(&sinfo->lock);
@@ -1205,19 +1204,38 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
num_bytes = cache->length - cache->reserved - cache->pinned -
cache->bytes_super - cache->used;
- sinfo_used = btrfs_space_info_used(sinfo, true);
/*
- * sinfo_used + num_bytes should always <= sinfo->total_bytes.
- *
- * Here we make sure if we mark this bg RO, we still have enough
- * free space as buffer.
+ * Data never overcommits, even in mixed mode, so do just the straight
+ * check of left over space in how much we have allocated.
*/
- if (force || (sinfo_used + num_bytes <= sinfo->total_bytes)) {
+ if (force) {
+ ret = 0;
+ } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
+ u64 sinfo_used = btrfs_space_info_used(sinfo, true);
+
+ /*
+ * Here we make sure if we mark this bg RO, we still have enough
+ * free space as buffer.
+ */
+ if (sinfo_used + num_bytes <= sinfo->total_bytes)
+ ret = 0;
+ } else {
+ /*
+ * We overcommit metadata, so we need to do the
+ * btrfs_can_overcommit check here, and we need to pass in
+ * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
+ * leeway to allow us to mark this block group as read only.
+ */
+ if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
+ BTRFS_RESERVE_NO_FLUSH))
+ ret = 0;
+ }
+
+ if (!ret) {
sinfo->bytes_readonly += num_bytes;
cache->ro++;
list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
- ret = 0;
}
out:
spin_unlock(&cache->lock);
@@ -1225,9 +1243,6 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
btrfs_info(cache->fs_info,
"unable to make block group %llu ro", cache->start);
- btrfs_info(cache->fs_info,
- "sinfo_used=%llu bg_num_bytes=%llu",
- sinfo_used, num_bytes);
btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
}
return ret;