From 86db25785a6e7cacc1ee868fe437e8a2957eae94 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 20 Feb 2013 16:23:40 -0500 Subject: [PATCH] Btrfs: fix max chunk size on raid5/6 We try to limit the size of a chunk to 10GB, which keeps the unit of work reasonable during balance and resize operations. The limit checks were taking into account the number of copies of the data we had but what they really should be doing is comparing against the logical size of the chunk we're creating. This moves the code around a little to use the count of data stripes from raid5/6. Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5d6010ba8b7e..538c5cfa005f 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3837,10 +3837,6 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, */ data_stripes = num_stripes / ncopies; - if (stripe_size * ndevs > max_chunk_size * ncopies) { - stripe_size = max_chunk_size * ncopies; - do_div(stripe_size, ndevs); - } if (type & BTRFS_BLOCK_GROUP_RAID5) { raid_stripe_len = find_raid56_stripe_len(ndevs - 1, btrfs_super_stripesize(info->super_copy)); @@ -3851,6 +3847,27 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans, btrfs_super_stripesize(info->super_copy)); data_stripes = num_stripes - 2; } + + /* + * Use the number of data stripes to figure out how big this chunk + * is really going to be in terms of logical address space, + * and compare that answer with the max chunk size + */ + if (stripe_size * data_stripes > max_chunk_size) { + u64 mask = (1ULL << 24) - 1; + stripe_size = max_chunk_size; + do_div(stripe_size, data_stripes); + + /* bump the answer up to a 16MB boundary */ + stripe_size = (stripe_size + mask) & ~mask; + + /* but don't go higher than the limits we found + * while searching for free extents + */ + if (stripe_size > devices_info[ndevs-1].max_avail) + stripe_size = devices_info[ndevs-1].max_avail; + } + do_div(stripe_size, dev_stripes); /* align to BTRFS_STRIPE_LEN */ -- 2.30.2