From: Josef Bacik Date: Wed, 15 Nov 2017 21:20:52 +0000 (-0500) Subject: btrfs: fix deadlock when writing out space cache X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=b77000ed558daa3bef0899d29bf171b8c9b5e6a8;p=openwrt%2Fstaging%2Fblogic.git btrfs: fix deadlock when writing out space cache If we fail to prepare our pages for whatever reason (out of memory in our case) we need to make sure to drop the block_group->data_rwsem, otherwise hilarity ensues. Signed-off-by: Josef Bacik Reviewed-by: Omar Sandoval Reviewed-by: Liu Bo Reviewed-by: David Sterba [ add label and use existing unlocking code ] Signed-off-by: David Sterba --- diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index cdc9f4015ec3..4426d1c73e50 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -1264,7 +1264,7 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, /* Lock all pages first so we can lock the extent safely. */ ret = io_ctl_prepare_pages(io_ctl, inode, 0); if (ret) - goto out; + goto out_unlock; lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, &cached_state); @@ -1358,6 +1358,7 @@ out_nospc_locked: out_nospc: cleanup_write_cache_enospc(inode, io_ctl, &cached_state); +out_unlock: if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) up_write(&block_group->data_rwsem);