From a6dbd429d8dd3382bbd9594b8d2ec74843a260d9 Mon Sep 17 00:00:00 2001 From: Josef Bacik <josef@redhat.com> Date: Wed, 11 Nov 2009 15:53:34 -0500 Subject: [PATCH] Btrfs: fix panic when trying to destroy a newly allocated There is a problem where iget5_locked will look for an inode, not find it, and then subsequently try to allocate it. Another CPU will have raced in and allocated the inode instead, so when iget5_locked gets the inode spin lock again and does a search, it finds the new inode. So it goes ahead and calls destroy_inode on the inode it just allocated. The problem is we don't set BTRFS_I(inode)->root until the new inode is completely initialized. This patch makes us set root to NULL when alloc'ing a new inode, so when we get to btrfs_destroy_inode and we see that root is NULL we can just free up the memory and continue on. This fixes the panic http://www.kerneloops.org/submitresult.php?number=812690 Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com> --- fs/btrfs/inode.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index d3d7d46a6af2d..ee92801fc5db7 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5180,6 +5180,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) ei->logged_trans = 0; ei->outstanding_extents = 0; ei->reserved_extents = 0; + ei->root = NULL; spin_lock_init(&ei->accounting_lock); btrfs_ordered_inode_tree_init(&ei->ordered_tree); INIT_LIST_HEAD(&ei->i_orphan); @@ -5195,6 +5196,14 @@ void btrfs_destroy_inode(struct inode *inode) WARN_ON(!list_empty(&inode->i_dentry)); WARN_ON(inode->i_data.nrpages); + /* + * This can happen where we create an inode, but somebody else also + * created the same inode and we need to destroy the one we already + * created. + */ + if (!root) + goto free; + /* * Make sure we're properly removed from the ordered operation * lists. @@ -5230,6 +5239,7 @@ void btrfs_destroy_inode(struct inode *inode) } inode_tree_del(inode); btrfs_drop_extent_cache(inode, 0, (u64)-1, 0); +free: kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode)); } -- GitLab