From 2968b1f48bd7366dd7310acde1ee6d1bf7791142 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 1 Oct 2015 12:55:18 -0400 Subject: [PATCH] Btrfs: don't continue setting up space cache when enospc If we hit ENOSPC when setting up a space cache don't bother setting up any of the other space cache's in this transaction, it'll just induce unnecessary latency. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 19 +++++++++++++++++++ fs/btrfs/transaction.h | 1 + 2 files changed, 20 insertions(+) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index febb5bc35a64..3185c457f025 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3402,6 +3402,15 @@ again: } spin_unlock(&block_group->lock); + /* + * We hit an ENOSPC when setting up the cache in this transaction, just + * skip doing the setup, we've already cleared the cache so we're safe. + */ + if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) { + ret = -ENOSPC; + goto out_put; + } + /* * Try to preallocate enough space based on how big the block group is. * Keep in mind this has to include any pinned space which could end up @@ -3422,8 +3431,18 @@ again: ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages, num_pages, num_pages, &alloc_hint); + /* + * Our cache requires contiguous chunks so that we don't modify a bunch + * of metadata or split extents when writing the cache out, which means + * we can enospc if we are heavily fragmented in addition to just normal + * out of space conditions. So if we hit this just skip setting up any + * other block groups for this transaction, maybe we'll unpin enough + * space the next time around. + */ if (!ret) dcs = BTRFS_DC_SETUP; + else if (ret == -ENOSPC) + set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags); btrfs_free_reserved_data_space(inode, num_pages); out_put: diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 109b8b7fb48e..30ae75074ca4 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -34,6 +34,7 @@ enum btrfs_trans_state { #define BTRFS_TRANS_HAVE_FREE_BGS 0 #define BTRFS_TRANS_DIRTY_BG_RUN 1 +#define BTRFS_TRANS_CACHE_ENOSPC 2 struct btrfs_transaction { u64 transid; -- 2.20.1