Re: [PATCH] pnfsd-lexp: recall layout on truncate

[Boaz Harrosh <bharrosh@panasas.com>]

On 02/22/2011 04:09 PM, Benny Halevy wrote:
> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> ---
>  fs/nfsd/pnfsd.h      |    1 +
>  fs/nfsd/pnfsd_lexp.c |   76 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  fs/nfsd/vfs.c        |    4 ++
>  3 files changed, 79 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfsd/pnfsd.h b/fs/nfsd/pnfsd.h
> index 946f334..51dd982 100644
> --- a/fs/nfsd/pnfsd.h
> +++ b/fs/nfsd/pnfsd.h
> @@ -139,6 +139,7 @@ extern struct sockaddr pnfsd_lexp_addr;
>  extern size_t pnfs_lexp_addr_len;
>  
>  extern void pnfsd_lexp_init(struct inode *);
> +extern int pnfsd_lexp_recall_layout(struct inode *);
>  #endif /* CONFIG_PNFSD_LOCAL_EXPORT */
>  
>  #endif /* LINUX_NFSD_PNFSD_H */
> diff --git a/fs/nfsd/pnfsd_lexp.c b/fs/nfsd/pnfsd_lexp.c
> index bf2f403..736cc3f 100644
> --- a/fs/nfsd/pnfsd_lexp.c
> +++ b/fs/nfsd/pnfsd_lexp.c
> @@ -18,6 +18,8 @@
>   * by David M. Richter <richterd@citi.umich.edu>
>   */
>  
> +#include <linux/sched.h>
> +#include <linux/wait.h>
>  #include <linux/sunrpc/svc_xprt.h>
>  #include <linux/nfsd/nfs4layoutxdr.h>
>  
> @@ -28,6 +30,8 @@
>  struct sockaddr pnfsd_lexp_addr;
>  size_t pnfs_lexp_addr_len;
>  
> +static wait_queue_head_t lo_recall_wq;
> +
>  static int
>  pnfsd_lexp_layout_type(struct super_block *sb)
>  {
> @@ -196,8 +200,7 @@ static int
>  pnfsd_lexp_layout_return(struct inode *inode,
>  			 const struct nfsd4_pnfs_layoutreturn_arg *args)
>  {
> -	dprintk("%s: (unimplemented)\n", __func__);
> -
> +	wake_up_all(&lo_recall_wq);
>  	return 0;
>  }
>  
> @@ -220,6 +223,75 @@ static struct pnfs_export_operations pnfsd_lexp_ops = {
>  void
>  pnfsd_lexp_init(struct inode *inode)
>  {
> +	static bool init_once;
> +
>  	dprintk("%s: &pnfsd_lexp_ops=%p\n", __func__, &pnfsd_lexp_ops);
>  	inode->i_sb->s_pnfs_op = &pnfsd_lexp_ops;
> +
> +	if (!init_once++)
> +		init_waitqueue_head(&lo_recall_wq);
> +}
> +
> +static bool
> +has_no_layout(struct nfs4_file *fp)
> +{
> +	return list_empty(&fp->fi_layouts);
> +}
> +
> +/*
> + * recalls the layout if needed and waits synchronously for its return
> + */
> +int
> +pnfsd_lexp_recall_layout(struct inode *inode)
> +{
> +	struct nfs4_file *fp;
> +	struct nfsd4_pnfs_cb_layout cbl;
> +	struct pnfsd_cb_ctl cb_ctl;
> +	int status = 0;
> +
> +	dprintk("%s: begin\n", __func__);
> +	fp = find_file(inode);
> +	BUG_ON(!fp);
> +
> +	if (has_no_layout(fp))
> +		goto out;
> +
> +	memset(&cb_ctl, 0, sizeof(cb_ctl));
> +	status = pnfsd_get_cb_op(&cb_ctl);
> +	BUG_ON(status);
> +
> +	memset(&cbl, 0, sizeof(cbl));
> +	cbl.cbl_recall_type = RETURN_FILE;
> +	cbl.cbl_seg.layout_type = LAYOUT_NFSV4_1_FILES;
> +	/* for now, always recall the whole layout */
> +	cbl.cbl_seg.iomode = IOMODE_ANY;
> +	cbl.cbl_seg.offset = 0;
> +	cbl.cbl_seg.length = NFS4_MAX_UINT64;
> +
> +	while (!has_no_layout(fp)) {
> +		dprintk("%s: recalling layout\n", __func__);
> +		status = cb_ctl.cb_op->cb_layout_recall(inode->i_sb, inode, &cbl);
> +
> +		switch (status) {
> +		case 0:
> +		case -EAGAIN:
> +			break;
> +		case -ENOENT:	/* no matching layout */
> +			status = 0;
> +			goto out_put_cb;
> +		default:
> +			goto out_put_cb;
> +		}
> +
> +		dprintk("%s: waiting\n", __func__);
> +		status = wait_event_interruptible(lo_recall_wq, has_no_layout(fp));
> +		if (status)
> +			break;
> +	}
> +out_put_cb:
> +	pnfsd_put_cb_op(&cb_ctl);
> +out:
> +	put_nfs4_file(fp);
> +	dprintk("%s: status=%d\n", __func__, status);
> +	return status;
>  }
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 79ba25f..021e89e 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -36,6 +36,7 @@
>  #ifdef CONFIG_NFSD_V4
>  #include "acl.h"
>  #include "idmap.h"
> +#include "pnfsd.h"
>  #include <linux/nfsd4_spnfs.h>
>  #endif /* CONFIG_NFSD_V4 */
>  #if defined(CONFIG_SPNFS_BLOCK)
> @@ -384,6 +385,9 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
>  					NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
>  			if (err)
>  				goto out;
> +#if defined(CONFIG_PNFSD_LOCAL_EXPORT)
> +			pnfsd_lexp_recall_layout(inode);

Ha, I just realized, this is not good, for when CONFIG_PNFSD_LOCAL_EXPORT is set
but the actual sb is pnfs-exported by the file system like gfs2 and exofs.
You need to check if the FS is owned by the PNFSD_LOCAL_EXPORT.

Boaz

> +#endif /* CONFIG_PNFSD_LOCAL_EXPORT */
>  #if defined(CONFIG_SPNFS_BLOCK)
>  			if (pnfs_block_enabled(inode, 0)) {
>  				err = bl_layoutrecall(inode, RETURN_FILE,