From: Josef Bacik Date: Wed, 15 Nov 2017 21:20:52 +0000 (-0500) Subject: btrfs: fix deadlock when writing out space cache X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~7^2~53 X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com//%22stanciumarius94%40gmail.com/%22/%22http:/www.example.com/%22stanciumarius94%40gmail.com/%22?a=commitdiff_plain;h=8cfb3965ebcd9e02365f8c8e9f4c9f19fd0be004;p=linux-4.9.git btrfs: fix deadlock when writing out space cache [ Upstream commit b77000ed558daa3bef0899d29bf171b8c9b5e6a8 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index e4b48f377d3a..c56253a1e5b4 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -1253,7 +1253,7 @@ 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); @@ -1346,6 +1346,7 @@ out_nospc_locked: out_nospc: cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list); +out_unlock: if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) up_write(&block_group->data_rwsem);