[PATCH 14/43] btrfs: hold a ref on the root in fixup_tree_root_location

Josef Bacik
2020-01-17T21:26:34Z

Looking up the inode from an arbitrary tree means we need to hold a ref
on that root.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/inode.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8cd1b11c3151..85104886c1e7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5026,6 +5026,10 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
err = PTR_ERR(new_root);
goto out;
}
+ if (!btrfs_grab_fs_root(new_root)) {
+ err = -ENOENT;
+ goto out;
+ }

*sub_root = new_root;
location->objectid = btrfs_root_dirid(&new_root->root_item);
@@ -5268,6 +5272,8 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
} else {
inode = btrfs_iget(dir->i_sb, &location, sub_root);
}
+ if (root != sub_root)
+ btrfs_put_fs_root(sub_root);
srcu_read_unlock(&fs_info->subvol_srcu, index);

if (!IS_ERR(inode) && root != sub_root) {
--
2.24.1