From 68a82277b8619e6d0f2738b1d9b160b627e81e92 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 24 Jan 2011 21:43:20 +0000 Subject: [PATCH] Btrfs: use the global block reserve if we cannot reserve space We call use_block_rsv right before we make an allocation in order to make sure we have enough space. Now normally people have called btrfs_start_transaction() with the appropriate amount of space that we need, so we just use some of that pre-reserved space and move along happily. The problem is where people use btrfs_join_transaction(), which doesn't actually reserve any space. So we try and reserve space here, but we cannot flush delalloc, so this forces us to return -ENOSPC when in reality we have plenty of space. The most common symptom is seeing a bunch of "couldn't dirty inode" messages in syslog. With xfstests 224 we end up falling back to start_transaction and then doing all the flush delalloc stuff which causes to hang for a very long time. So instead steal from the global reserve, which is what this is meant for anyway. With this patch and the other 2 I have sent xfstests 224 now passes successfully. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 7af618dcf2c0..ff6bbfd75cf7 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5646,6 +5646,7 @@ use_block_rsv(struct btrfs_trans_handle *trans, struct btrfs_root *root, u32 blocksize) { struct btrfs_block_rsv *block_rsv; + struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv; int ret; block_rsv = get_block_rsv(trans, root); @@ -5653,14 +5654,39 @@ use_block_rsv(struct btrfs_trans_handle *trans, if (block_rsv->size == 0) { ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize, 0); - if (ret) + /* + * If we couldn't reserve metadata bytes try and use some from + * the global reserve. + */ + if (ret && block_rsv != global_rsv) { + ret = block_rsv_use_bytes(global_rsv, blocksize); + if (!ret) + return global_rsv; return ERR_PTR(ret); + } else if (ret) { + return ERR_PTR(ret); + } return block_rsv; } ret = block_rsv_use_bytes(block_rsv, blocksize); if (!ret) return block_rsv; + if (ret) { + WARN_ON(1); + ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize, + 0); + if (!ret) { + spin_lock(&block_rsv->lock); + block_rsv->size += blocksize; + spin_unlock(&block_rsv->lock); + return block_rsv; + } else if (ret && block_rsv != global_rsv) { + ret = block_rsv_use_bytes(global_rsv, blocksize); + if (!ret) + return global_rsv; + } + } return ERR_PTR(-ENOSPC); }