Btrfs: Add drop inode func to avoid data=ordered deadlock

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f65b258..a2c2d6d 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1144,6 +1144,7 @@ int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page);
 int btrfs_readpage(struct file *file, struct page *page);
 void btrfs_delete_inode(struct inode *inode);
+void btrfs_drop_inode(struct inode *inode);
 void btrfs_read_locked_inode(struct inode *inode);
 int btrfs_write_inode(struct inode *inode, int wait);
 void btrfs_dirty_inode(struct inode *inode);

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5260b47..e53d203 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -990,6 +990,25 @@ out:
 fail:
        return err;
 }
+
+void btrfs_drop_inode(struct inode *inode)
+{
+       struct btrfs_trans_handle *trans;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+
+       if (!BTRFS_I(inode)->ordered_trans) {
+               generic_drop_inode(inode);
+               return;
+       }
+       /* nasty, but it prevents a deadlock with data=ordered by preventing
+        * a commit until after this inode is done
+        */
+       trans = btrfs_start_transaction(root, 1);
+       generic_drop_inode(inode);
+       /* note, the inode is now untouchable */
+       btrfs_end_transaction(trans, root);
+}
+
 void btrfs_delete_inode(struct inode *inode)
 {
        struct btrfs_trans_handle *trans;

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9ab4086..4deea39 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -425,6 +425,7 @@ static struct file_system_type btrfs_fs_type = {
 
 static struct super_operations btrfs_super_ops = {
        .delete_inode   = btrfs_delete_inode,
+       .drop_inode     = btrfs_drop_inode,
        .put_super      = btrfs_put_super,
        .read_inode     = btrfs_read_locked_inode,
        .write_super    = btrfs_write_super,