[Cluster-devel] Re: [PATCH 1/2] NLM failover unlock commands

[Wendy Cheng <wcheng@redhat.com>]

Christoph Hellwig wrote:
> Ok, I played around with this and cleaned up the ip/path codepathes to
> be entirely setup which helped the code quite a bit.  Also a few other
>   
Thanks for doing this :) . In the middle of running it with our cluster 
test - if passed, will repost it. Get your "signed-off" line ready ?

-- Wendy
> cleanups and two bugfixes (postive error code returned and missing
> path_release) fell out of it.  I still don't like what's going on in
> fs/lockd/svcsubs.c, it would be much better if the cluster unlock code
> simply didn't use nlm_traverse_files but did it's own loop over
> the nlm hosts.  That should also absolete the second patch.
>   
>
> Index: linux-2.6/fs/nfsd/nfsctl.c
> ===================================================================
> --- linux-2.6.orig/fs/nfsd/nfsctl.c	2008-01-08 18:36:37.000000000 +0100
> +++ linux-2.6/fs/nfsd/nfsctl.c	2008-01-08 18:45:55.000000000 +0100
> @@ -22,6 +22,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/pagemap.h>
>  #include <linux/init.h>
> +#include <linux/inet.h>
>  #include <linux/string.h>
>  #include <linux/smp_lock.h>
>  #include <linux/ctype.h>
> @@ -35,6 +36,7 @@
>  #include <linux/nfsd/cache.h>
>  #include <linux/nfsd/xdr.h>
>  #include <linux/nfsd/syscall.h>
> +#include <linux/lockd/lockd.h>
>  
>  #include <asm/uaccess.h>
>  
> @@ -52,6 +54,8 @@ enum {
>  	NFSD_Getfs,
>  	NFSD_List,
>  	NFSD_Fh,
> +	NFSD_FO_UnlockIP,
> +	NFSD_FO_UnlockFS,
>  	NFSD_Threads,
>  	NFSD_Pool_Threads,
>  	NFSD_Versions,
> @@ -88,6 +92,9 @@ static ssize_t write_leasetime(struct fi
>  static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
>  #endif
>  
> +static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
> +static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);
> +
>  static ssize_t (*write_op[])(struct file *, char *, size_t) = {
>  	[NFSD_Svc] = write_svc,
>  	[NFSD_Add] = write_add,
> @@ -97,6 +104,8 @@ static ssize_t (*write_op[])(struct file
>  	[NFSD_Getfd] = write_getfd,
>  	[NFSD_Getfs] = write_getfs,
>  	[NFSD_Fh] = write_filehandle,
> +	[NFSD_FO_UnlockIP] = failover_unlock_ip,
> +	[NFSD_FO_UnlockFS] = failover_unlock_fs,
>  	[NFSD_Threads] = write_threads,
>  	[NFSD_Pool_Threads] = write_pool_threads,
>  	[NFSD_Versions] = write_versions,
> @@ -288,6 +297,55 @@ static ssize_t write_getfd(struct file *
>  	return err;
>  }
>  
> +static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
> +{
> +	__be32 server_ip;
> +	char *fo_path;
> +	char *mesg;
> +
> +	/* sanity check */
> +	if (size <= 0)
> +		return -EINVAL;
> +
> +	if (buf[size-1] == '\n')
> +		buf[size-1] = 0;
> +
> +	fo_path = mesg = buf;
> +	if (qword_get(&mesg, fo_path, size) < 0)
> +		return -EINVAL;
> +
> +	server_ip = in_aton(fo_path);
> +	return nlmsvc_failover_ip(server_ip[0]);
> +}
> +
> +static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
> +{
> +	struct nameidata nd;
> +	char *fo_path;
> +	char *mesg;
> +	int error;
> +
> +	/* sanity check */
> +	if (size <= 0)
> +		return -EINVAL;
> +
> +	if (buf[size-1] == '\n')
> +		buf[size-1] = 0;
> +
> +	fo_path = mesg = buf;
> +	if (qword_get(&mesg, fo_path, size) < 0)
> +		return -EINVAL;
> +
> +	error = path_lookup(fo_path, 0, &nd);
> +	if (error)
> +		return error;
> +
> +	error = nlmsvc_failover_path(&nd);
> +
> +	path_release(&nd);
> +	return error;
> +}
> +
>  static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
>  {
>  	/* request is:
> @@ -646,6 +704,8 @@ static int nfsd_fill_super(struct super_
>  		[NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
>  		[NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
>  		[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
> +		[NFSD_FO_UnlockIP] = {"unlock_ip", &transaction_ops, S_IWUSR|S_IRUSR},
> +		[NFSD_FO_UnlockFS] = {"unlock_filesystem", &transaction_ops, S_IWUSR|S_IRUSR},
>  		[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
>  		[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
>  		[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
> Index: linux-2.6/fs/lockd/svcsubs.c
> ===================================================================
> --- linux-2.6.orig/fs/lockd/svcsubs.c	2008-01-08 18:36:37.000000000 +0100
> +++ linux-2.6/fs/lockd/svcsubs.c	2008-01-08 18:44:11.000000000 +0100
> @@ -18,6 +18,8 @@
>  #include <linux/lockd/lockd.h>
>  #include <linux/lockd/share.h>
>  #include <linux/lockd/sm_inter.h>
> +#include <linux/module.h>
> +#include <linux/mount.h>
>  
>  #define NLMDBG_FACILITY		NLMDBG_SVCSUBS
>  
> @@ -87,7 +89,7 @@ nlm_lookup_file(struct svc_rqst *rqstp, 
>  	unsigned int	hash;
>  	__be32		nfserr;
>  
> -	nlm_debug_print_fh("nlm_file_lookup", f);
> +	nlm_debug_print_fh("nlm_lookup_file", f);
>  
>  	hash = file_hash(f);
>  
> @@ -123,6 +125,9 @@ nlm_lookup_file(struct svc_rqst *rqstp, 
>  
>  	hlist_add_head(&file->f_list, &nlm_files[hash]);
>  
> +	/* fill in f_iaddr for nlm lock failover */
> +	file->f_iaddr = rqstp->rq_daddr;
> +
>  found:
>  	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
>  	*result = file;
> @@ -194,12 +199,63 @@ again:
>  	return 0;
>  }
>  
> +static int
> +nlmsvc_fo_unlock_match_path(void *datap, struct nlm_file *file)
> +{
> +	struct nameidata *nd = datap;
> +	return nd->mnt == file->f_file->f_path.mnt;
> +}
> +
> +static int
> +nlmsvc_fo_unlock_match_ip(void *datap, struct nlm_file *file)
> +{
> +	struct in_addr *in = datap;
> +
> +	return file->f_iaddr.addr.s_addr == in->s_addr;
> +}
> +
> +/*
> + * To fit the logic into current lockd code structure, we add a
> + * little wrapper function here. The real matching task should be
> + * carried out by nlm_fo_check_fsid().
> + */
> +
> +static int nlmsvc_fo_match_path(struct nlm_host *dummy1,
> +		struct nlm_host *dummy2)
> +{
> +        return 1;
> +}
> +
> +static int nlmsvc_fo_match_ip(struct nlm_host *dummy1, struct nlm_host *dummy2)
> +{
> +        return 1;
> +}
> +
>  /*
>   * Inspect a single file
>   */
>  static inline int
>  nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
>  {
> +	/*
> +	 * Cluster failover has timing constraints. There is a slight
> +	 * performance hit if nlm_fo_unlock_match() is implemented as
> +	 * a match fn (since it will be invoked for each block, share,
> +	 * and lock later when the lists are traversed). Instead, we
> +	 * add path-matching logic into the following unlikely clause.
> +	 * If matches, the dummy nlmsvc_fo_match will always return
> +	 * true.
> +	 */
> +	dprintk("nlm_inspect_files: file=%p\n", file);
> +	if (unlikely(match == nlmsvc_fo_match_path)) {
> +		if (!nlmsvc_fo_unlock_match_path(host, file))
> +			return 0;
> +	}
> +	if (unlikely(match == nlmsvc_fo_match_ip)) {
> +		if (!nlmsvc_fo_unlock_match_ip(host, file))
> +			return 0;
> +	}
> +
>  	nlmsvc_traverse_blocks(host, file, match);
>  	nlmsvc_traverse_shares(host, file, match);
>  	return nlm_traverse_locks(host, file, match);
> @@ -370,3 +426,22 @@ nlmsvc_invalidate_all(void)
>  	 */
>  	nlm_traverse_files(NULL, nlmsvc_is_client);
>  }
> +
> +/*
> + * Release locks associated with an export fsid upon failover
> + *      invoked via nfsd nfsctl call (write_fo_unlock).
> + */
> +int
> +nlmsvc_failover_path(struct nameidata *nd)
> +{
> +	return nlm_traverse_files((struct nlm_host*)nd, nlmsvc_fo_match_path);
> +}
> +EXPORT_SYMBOL_GPL(nlmsvc_failover_path);
> +
> +int
> +nlmsvc_failover_ip(__be32 server_addr)
> +{
> +	return nlm_traverse_files((struct nlm_host *)&server_addr,
> +				nlmsvc_fo_match_ip);
> +}
> +EXPORT_SYMBOL_GPL(nlmsvc_failover_ip);
> Index: linux-2.6/include/linux/lockd/lockd.h
> ===================================================================
> --- linux-2.6.orig/include/linux/lockd/lockd.h	2008-01-08 18:36:37.000000000 +0100
> +++ linux-2.6/include/linux/lockd/lockd.h	2008-01-08 18:44:44.000000000 +0100
> @@ -113,6 +113,7 @@ struct nlm_file {
>  	unsigned int		f_locks;	/* guesstimate # of locks */
>  	unsigned int		f_count;	/* reference count */
>  	struct mutex		f_mutex;	/* avoid concurrent access */
> +	union svc_addr_u	f_iaddr;	/* server ip for failover */
>  };
>  
>  /*
> @@ -214,6 +215,12 @@ void		  nlmsvc_mark_resources(void);
>  void		  nlmsvc_free_host_resources(struct nlm_host *);
>  void		  nlmsvc_invalidate_all(void);
>  
> +/*
> + * Cluster failover support
> + */
> +int           nlmsvc_failover_path(struct nameidata *nd);
> +int           nlmsvc_failover_ip(__be32 server_addr);
> +
>  static __inline__ struct inode *
>  nlmsvc_file_inode(struct nlm_file *file)
>  {
>