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authorMiao Xie <miaox@cn.fujitsu.com>2013-09-25 21:47:45 +0800
committerChris Mason <chris.mason@fusionio.com>2013-11-11 21:54:28 -0500
commit20dd2cbf01888a91fdd921403040a710b275a1ff (patch)
treec669c83c8f9d84782ff653c31907ac9b26745350 /fs/btrfs/relocation.c
parent0a4e558609dd4df30a58a07d9eb14c5ddc2c1241 (diff)
Btrfs: fix BUG_ON() casued by the reserved space migration
When we did space balance and snapshot creation at the same time, we might meet the following oops: kernel BUG at fs/btrfs/inode.c:3038! [SNIP] Call Trace: [<ffffffffa0411ec7>] btrfs_orphan_cleanup+0x293/0x407 [btrfs] [<ffffffffa042dc45>] btrfs_mksubvol.isra.28+0x259/0x373 [btrfs] [<ffffffffa042de85>] btrfs_ioctl_snap_create_transid+0x126/0x156 [btrfs] [<ffffffffa042dff1>] btrfs_ioctl_snap_create_v2+0xd0/0x121 [btrfs] [<ffffffffa0430b2c>] btrfs_ioctl+0x414/0x1854 [btrfs] [<ffffffff813b60b7>] ? __do_page_fault+0x305/0x379 [<ffffffff811215a9>] vfs_ioctl+0x1d/0x39 [<ffffffff81121d7c>] do_vfs_ioctl+0x32d/0x3e2 [<ffffffff81057fe7>] ? finish_task_switch+0x80/0xb8 [<ffffffff81121e88>] SyS_ioctl+0x57/0x83 [<ffffffff813b39ff>] ? do_device_not_available+0x12/0x14 [<ffffffff813b99c2>] system_call_fastpath+0x16/0x1b [SNIP] RIP [<ffffffffa040da40>] btrfs_orphan_add+0xc3/0x126 [btrfs] The reason of the problem is that the relocation root creation stole the reserved space, which was reserved for orphan item deletion. There are several ways to fix this problem, one is to increasing the reserved space size of the space balace, and then we can use that space to create the relocation tree for each fs/file trees. But it is hard to calculate the suitable size because we doesn't know how many fs/file trees we need relocate. We fixed this problem by reserving the space for relocation root creation actively since the space it need is very small (one tree block, used for root node copy), then we use that reserved space to create the relocation tree. If we don't reserve space for relocation tree creation, we will use the reserved space of the balance. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/relocation.c')
-rw-r--r--fs/btrfs/relocation.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 0359eecac95d..a945374993f7 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1383,6 +1383,7 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
{
struct btrfs_root *reloc_root;
struct reloc_control *rc = root->fs_info->reloc_ctl;
+ struct btrfs_block_rsv *rsv;
int clear_rsv = 0;
int ret;
@@ -1396,13 +1397,14 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
return 0;
- if (!trans->block_rsv) {
+ if (!trans->reloc_reserved) {
+ rsv = trans->block_rsv;
trans->block_rsv = rc->block_rsv;
clear_rsv = 1;
}
reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
if (clear_rsv)
- trans->block_rsv = NULL;
+ trans->block_rsv = rsv;
ret = __add_reloc_root(reloc_root);
BUG_ON(ret < 0);