Re: [V2, 1/1] NFSv4.1: remove pnfs_layout_hdr from pnfs_destroy_all_layouts tmp_list

[Vitaliy Gusev <gusev.vitaliy@nexenta.com>]

On 01/-10/-28163 10:59 PM, Andy Adamson wrote:
> From: Andy Adamson<andros@netapp.com>
>
> Prevents an infinite loop as list was never emptied.
>
> Signed-off-by: Andy Adamson<andros@netapp.com>
> +++ b/fs/nfs/pnfs.c
> @@ -383,6 +383,7 @@ pnfs_destroy_all_layouts(struct nfs_client *clp)
>   				plh_layouts);
>   		dprintk("%s freeing layout for inode %lu\n", __func__,
>   			lo->plh_inode->i_ino);
> +		list_del_init(&lo->plh_layouts);
>   		pnfs_destroy_layout(NFS_I(lo->plh_inode));

Shouldn't pnfs_destroy_layout() do it ?

Really see:

   pnfs_destroy_layout(struct nfs_inode *nfsi)
   {
   	struct pnfs_layout_hdr *lo;
   	LIST_HEAD(tmp_list);

   	spin_lock(&nfsi->vfs_inode.i_lock);
   	lo = nfsi->layout;
    ^^^^^^^^^^^^^^^^^^^^
Here is our "lo".


   	if (lo) {
   		lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
   		mark_matching_lsegs_invalid(lo, &tmp_list, IOMODE_ANY);
   	}
   	spin_unlock(&nfsi->vfs_inode.i_lock);
   	pnfs_free_lseg_list(&tmp_list);
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It does cleanup and deletes lo from the list.


I think really problem is more deeper. I investigated  debug messages:

    [  701.210784] put_lseg: lseg ffff88002cc36108 ref 5721 valid 1
    [  701.463495] pnfs_destroy_all_layouts freeing layout for inode 9
    [  701.465382] mark_matching_lsegs_invalid:Begin lo ffff880031b35ed8
    [  701.467172] mark_matching_lsegs_invalid: freeing lseg 
ffff88002cc36108 iomode 2 offset 0 length 18446744073709551615


    [701.470401] 701.470401] mark_lseg_invalid: lseg ffff88002cc36108 
ref 5720
    [  701.472071] mark_matching_lsegs_invalid:Return 1
    [  701.473623] pnfs_destroy_all_layouts freeing layout for inode 9
    [  701.475302] mark_matching_lsegs_invalid:Begin lo ffff880031b35ed8
    [  701.476981] mark_matching_lsegs_invalid: freeing lseg 
ffff88002cc36108 iomode 2 offset 0 length 18446744073709551615
    [  701.480549] mark_matching_lsegs_invalid:Return 1


    [  701.482136] pnfs_destroy_all_layouts freeing layout for inode 9
    [  701.483802] mark_matching_lsegs_invalid:Begin lo ffff880031b35ed8
    [  701.485461] mark_matching_lsegs_invalid: freeing lseg 
ffff88002cc36108 iomode 2 offset 0 length 18446744073709551615
    [  701.488598] mark_matching_lsegs_invalid:Return 1   ...


"Return 1" shows that mark_lseg_invalid() didn't do anything, because at 
first call it mark segment as invalid.

Also you can see that segment ref counter for last put_lseg() is 5720. I 
suppose that leak of refconter is real reason of the inifinite loop.


---
Thanks,
Vitaliy Gusev