NFS: Add a helper nfs_client_for_each_server()

Add a helper nfs_client_for_each_server() to iterate through all the
filesystems that are attached to a struct nfs_client, and apply
a function to all the active ones.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2020-02-26 19:16:09 -05:00
parent 58ac3e5923
commit 3c9e502b59
2 changed files with 38 additions and 1 deletions

View File

@ -417,7 +417,9 @@ extern int __init register_nfs_fs(void);
extern void __exit unregister_nfs_fs(void);
extern bool nfs_sb_active(struct super_block *sb);
extern void nfs_sb_deactive(struct super_block *sb);
extern int nfs_client_for_each_server(struct nfs_client *clp,
int (*fn)(struct nfs_server *, void *),
void *data);
/* io.c */
extern void nfs_start_io_read(struct inode *inode);
extern void nfs_end_io_read(struct inode *inode);

View File

@ -176,6 +176,41 @@ void nfs_sb_deactive(struct super_block *sb)
}
EXPORT_SYMBOL_GPL(nfs_sb_deactive);
static int __nfs_list_for_each_server(struct list_head *head,
int (*fn)(struct nfs_server *, void *),
void *data)
{
struct nfs_server *server, *last = NULL;
int ret = 0;
rcu_read_lock();
list_for_each_entry_rcu(server, head, client_link) {
if (!nfs_sb_active(server->super))
continue;
rcu_read_unlock();
if (last)
nfs_sb_deactive(last->super);
last = server;
ret = fn(server, data);
if (ret)
goto out;
rcu_read_lock();
}
rcu_read_unlock();
out:
if (last)
nfs_sb_deactive(last->super);
return ret;
}
int nfs_client_for_each_server(struct nfs_client *clp,
int (*fn)(struct nfs_server *, void *),
void *data)
{
return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
}
EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
/*
* Deliver file system statistics to userspace
*/