Josef Bacik
2009-Oct-16 16:08 UTC
[PATCH] Btrfs: fix panic when trying to destroy a newly allocated inode
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> --- fs/btrfs/inode.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 78139ef..f69e5e0 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5128,6 +5128,7 @@ 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); @@ -5144,6 +5145,14 @@ void btrfs_destroy_inode(struct inode *inode) 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. */ @@ -5178,6 +5187,7 @@ 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)); } -- 1.6.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html