Re: [syzbot] Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback

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Subject: Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback
Author: lizhi.xu@xxxxxxxxxxxxx

wait for writeback done before release inode

#syz test: upstream c0ecd6388360

diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index e0d34e4e9076..cddbd7cc39e5 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -218,7 +218,13 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 		if ((S_ISREG(inode->i_mode)) && (filp->f_mode & FMODE_WRITE))
 			retval = filemap_fdatawrite(inode->i_mapping);
 
+		printk("del, ind: %p, ino: %lx, ino is dirty: %d, %s\n", inode, inode->i_ino, inode->i_state & I_DIRTY,  __func__);
 		spin_lock(&inode->i_lock);
+		if (inode->i_state & I_DIRTY) {
+			spin_unlock(&inode->i_lock);
+			wait_on_bit_timeout(&inode->i_state, ~I_DIRTY, TASK_UNINTERRUPTIBLE, HZ*100);
+			spin_lock(&inode->i_lock);
+		}
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
 		put_err = p9_fid_put(fid);