btrfs: bail out of uuid tree scanning if we're closing

In doing my fsstress+EIO stress testing I started running into issues
where umount would get stuck forever because the uuid checker was
chewing through the thousands of subvolumes I had created.

We shouldn't block umount on this, simply bail if we're unmounting the
fs.  We need to make sure we don't mark the UUID tree as ok, so we only
set that bit if we made it through the whole rescan operation, but
otherwise this is completely safe.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik 2020-02-14 15:05:01 -05:00 committed by David Sterba
parent 97f4dd09da
commit c94bec2c61
3 changed files with 13 additions and 2 deletions

View File

@ -2847,7 +2847,9 @@ static int btrfs_uuid_rescan_kthread(void *data)
*/
ret = btrfs_uuid_tree_iterate(fs_info);
if (ret < 0) {
btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
if (ret != -EINTR)
btrfs_warn(fs_info, "iterating uuid_tree failed %d",
ret);
up(&fs_info->uuid_tree_rescan_sem);
return ret;
}

View File

@ -322,6 +322,10 @@ again_search_slot:
}
while (1) {
if (btrfs_fs_closing(fs_info)) {
ret = -EINTR;
goto out;
}
cond_resched();
leaf = path->nodes[0];
slot = path->slots[0];

View File

@ -4325,6 +4325,7 @@ int btrfs_uuid_scan_kthread(void *data)
struct btrfs_root_item root_item;
u32 item_size;
struct btrfs_trans_handle *trans = NULL;
bool closing = false;
path = btrfs_alloc_path();
if (!path) {
@ -4337,6 +4338,10 @@ int btrfs_uuid_scan_kthread(void *data)
key.offset = 0;
while (1) {
if (btrfs_fs_closing(fs_info)) {
closing = true;
break;
}
ret = btrfs_search_forward(root, &key, path,
BTRFS_OLDEST_GENERATION);
if (ret) {
@ -4436,7 +4441,7 @@ out:
btrfs_end_transaction(trans);
if (ret)
btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
else
else if (!closing)
set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
up(&fs_info->uuid_tree_rescan_sem);
return 0;