From 01cd390903e00c8f42ba0e84f25a70e3d613a15c Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 15 Jul 2022 13:59:31 +0200 Subject: Revert "btrfs: turn fs_info member buffer_radix into XArray" This reverts commit 8ee922689d67b7cfa6acbe2aa1ee76ac72e6fc8a. Revert the xarray conversion, there's a problem with potential sleep-inside-spinlock [1] when calling xa_insert that triggers GFP_NOFS allocation. The radix tree used the preloading mechanism to avoid sleeping but this is not available in xarray. Conversion from spin lock to mutex is possible but at time of rc6 is riskier than a clean revert. [1] https://lore.kernel.org/linux-btrfs/cover.1657097693.git.fdmanana@suse.com/ Reported-by: Filipe Manana Signed-off-by: David Sterba --- fs/btrfs/tests/btrfs-tests.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/tests/btrfs-tests.c') diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c index c8c4efc9a3fb..d8e56edd6991 100644 --- a/fs/btrfs/tests/btrfs-tests.c +++ b/fs/btrfs/tests/btrfs-tests.c @@ -150,8 +150,8 @@ struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize) void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info) { - unsigned long index; - struct extent_buffer *eb; + struct radix_tree_iter iter; + void **slot; struct btrfs_device *dev, *tmp; if (!fs_info) @@ -163,9 +163,25 @@ void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info) test_mnt->mnt_sb->s_fs_info = NULL; - xa_for_each(&fs_info->extent_buffers, index, eb) { + spin_lock(&fs_info->buffer_lock); + radix_tree_for_each_slot(slot, &fs_info->buffer_radix, &iter, 0) { + struct extent_buffer *eb; + + eb = radix_tree_deref_slot_protected(slot, &fs_info->buffer_lock); + if (!eb) + continue; + /* Shouldn't happen but that kind of thinking creates CVE's */ + if (radix_tree_exception(eb)) { + if (radix_tree_deref_retry(eb)) + slot = radix_tree_iter_retry(&iter); + continue; + } + slot = radix_tree_iter_resume(slot, &iter); + spin_unlock(&fs_info->buffer_lock); free_extent_buffer_stale(eb); + spin_lock(&fs_info->buffer_lock); } + spin_unlock(&fs_info->buffer_lock); btrfs_mapping_tree_free(&fs_info->mapping_tree); list_for_each_entry_safe(dev, tmp, &fs_info->fs_devices->devices, -- cgit v1.2.3