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SUNRPC: pipefs per-net operations helper introduced

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During per-net pipes creation and destruction we have to make sure, that pipefs
sb exists for the whole creation/destruction cycle. This is done by using
special mutex which controls pipefs sb reference on network namespace context.
Helper consists of two parts: first of them (rpc_get_dentry_net) searches for
dentry with specified name and returns with mutex taken on success. When pipe
creation or destructions is completed, caller should release this mutex by
rpc_put_dentry_net call.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Stanislav Kinsbursky 2011-12-26 15:39:39 +03:00 committed by Trond Myklebust
parent 90c4e82999
commit c21a588f35
4 changed files with 41 additions and 0 deletions
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3
include/linux/sunrpc/rpc_pipe_fs.h
View File

@ -53,6 +53,9 @@ enum {
extern struct dentry *rpc_d_lookup_sb(const struct super_block *sb, extern struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
const unsigned char *dir_name); const unsigned char *dir_name);
extern void rpc_pipefs_init_net(struct net *net);
extern struct super_block *rpc_get_sb_net(const struct net *net);
extern void rpc_put_sb_net(const struct net *net);
extern ssize_t rpc_pipe_generic_upcall(struct file *, struct rpc_pipe_msg *, extern ssize_t rpc_pipe_generic_upcall(struct file *, struct rpc_pipe_msg *,
char __user *, size_t); char __user *, size_t);

1
net/sunrpc/netns.h
View File

@ -11,6 +11,7 @@ struct sunrpc_net {
struct cache_detail *ip_map_cache; struct cache_detail *ip_map_cache;
struct super_block *pipefs_sb; struct super_block *pipefs_sb;
struct mutex pipefs_sb_lock;
}; };
extern int sunrpc_net_id; extern int sunrpc_net_id;

36
net/sunrpc/rpc_pipe.c
View File

@ -1023,6 +1023,40 @@ struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
} }
EXPORT_SYMBOL_GPL(rpc_d_lookup_sb); EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
void rpc_pipefs_init_net(struct net *net)
{
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
mutex_init(&sn->pipefs_sb_lock);
}
/*
* This call will be used for per network namespace operations calls.
* Note: Function will be returned with pipefs_sb_lock taken if superblock was
* found. This lock have to be released by rpc_put_sb_net() when all operations
* will be completed.
*/
struct super_block *rpc_get_sb_net(const struct net *net)
{
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
mutex_lock(&sn->pipefs_sb_lock);
if (sn->pipefs_sb)
return sn->pipefs_sb;
mutex_unlock(&sn->pipefs_sb_lock);
return NULL;
}
EXPORT_SYMBOL_GPL(rpc_get_sb_net);
void rpc_put_sb_net(const struct net *net)
{
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
BUG_ON(sn->pipefs_sb == NULL);
mutex_unlock(&sn->pipefs_sb_lock);
}
EXPORT_SYMBOL_GPL(rpc_put_sb_net);
static int static int
rpc_fill_super(struct super_block *sb, void *data, int silent) rpc_fill_super(struct super_block *sb, void *data, int silent)
{ {
@ -1077,7 +1111,9 @@ void rpc_kill_sb(struct super_block *sb)
struct net *net = sb->s_fs_info; struct net *net = sb->s_fs_info;
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
mutex_lock(&sn->pipefs_sb_lock);
sn->pipefs_sb = NULL; sn->pipefs_sb = NULL;
mutex_unlock(&sn->pipefs_sb_lock);
put_net(net); put_net(net);
blocking_notifier_call_chain(&rpc_pipefs_notifier_list, blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
RPC_PIPEFS_UMOUNT, RPC_PIPEFS_UMOUNT,

1
net/sunrpc/sunrpc_syms.c
View File

@ -38,6 +38,7 @@ static __net_init int sunrpc_init_net(struct net *net)
if (err) if (err)
goto err_ipmap; goto err_ipmap;
rpc_pipefs_init_net(net);
return 0; return 0;
err_ipmap: err_ipmap: