Wang Shilong got into a case where during inode eviction we were removing an extent map while it was pinned. This triggered a warning in remove_extent_mapping() because the extent map had the pinned flag set:
[ 1209.102076] [<ffffffffa04721b9>] remove_extent_mapping+0x69/0x70 [btrfs] [ 1209.102084] [<ffffffffa0466b06>] btrfs_evict_inode+0x96/0x4d0 [btrfs] [ 1209.102089] [<ffffffff81073010>] ? wake_atomic_t_function+0x40/0x40 [ 1209.102092] [<ffffffff8118ab2e>] evict+0x9e/0x190 [ 1209.102094] [<ffffffff8118b313>] iput+0xf3/0x180 [ 1209.102101] [<ffffffffa0461fd1>] btrfs_run_delayed_iputs+0xb1/0xd0 [btrfs] [ 1209.102107] [<ffffffffa045d358>] __btrfs_end_transaction+0x268/0x350 [btrfs] Therefore wait for any pending ordered extents, if any, which will trigger calls to unpin_extent_cache(), before removing the extent maps. Wang's solution of simply clearing the pinned bit wasn't enough, as after unpin_extent_cache() will be called and trigger another WARN_ON() because the lookup for the extent map returned NULL. Thanks Wang for finding out this. Signed-off-by: Filipe David Borba Manana <[email protected]> --- fs/btrfs/inode.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e889779..c2933fb 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4509,6 +4509,9 @@ static void evict_inode_truncate_pages(struct inode *inode) ASSERT(inode->i_state & I_FREEING); truncate_inode_pages(&inode->i_data, 0); + /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */ + btrfs_wait_ordered_range(inode, 0, (u64)-1); + write_lock(&map_tree->lock); while (!RB_EMPTY_ROOT(&map_tree->map)) { struct extent_map *em; @@ -4566,8 +4569,6 @@ void btrfs_evict_inode(struct inode *inode) btrfs_orphan_del(NULL, inode); goto no_delete; } - /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */ - btrfs_wait_ordered_range(inode, 0, (u64)-1); if (root->fs_info->log_root_recovering) { BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM, -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
