[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [Linux-cluster] Freeze with cluster-2.03.11



Kadlecsik Jozsef wrote:
On Thu, 2 Apr 2009, Wendy Cheng wrote:

Kadlecsik Jozsef wrote:
- commit 82d176ba485f2ef049fd303b9e41868667cebbdb
  gfs_drop_inode as .drop_inode replacing .put_inode.
  .put_inode was called without holding a lock, but .drop_inode
  is called under inode_lock held. Might it be a problem
Based on code reading ...
1. iput() gets inode_lock (a spin lock)
2. iput() calls iput_final()
3. iput_final() calls filesystem drop_inode(), followed by
generic_drop_inode()
4. generic_drop_inode() unlock inode_lock after doing all sorts of fun things
with the inode

So look to me that generic_drop_inode() statement within gfs_drop_inode() should be removed. Otherwise you would get double unlock and double list free.

I think those function calls are right: iput_final calls either the filesystem drop_inode function (in this case gfs_drop_inode) or generic_drop_inode. There's no double call of generic_drop_inode. However gfs_sync_page_i (and in turn filemap_fdatawrite and filemap_fdatawait) is now called under inode_lock held and that was not so in previous versions.
But I'm just speculating.

It *is* called twice unless my eyes deceive me

static inline void iput_final(struct inode *inode)
{
const struct super_operations *op = inode->i_sb->s_op;
void (*drop)(struct inode *) = generic_drop_inode;

if (op && op->drop_inode)
drop = op->drop_inode; /* gfs call generic_drop_inode() */
drop(inode); /* second call into generic_drop_inode() again. */
}

In short, *remove* line #73 from gfs-kernel/src/gfs/ops_super.c in your source and let us know how it goes.

I won't get a chance to start a test before Monday, sorry.

I'll be traveling next week as well. However, a few cautious words here:

Even this "fix" eventually solves your hang, running GFS on newer kernels with production system simply is *not* a good idea.

-- Wendy


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]