From 3c9e502b59fbd243cfac7cc6c875e432d285102a Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 26 Feb 2020 19:16:09 -0500 Subject: 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 --- fs/nfs/internal.h | 4 +++- fs/nfs/super.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index f80c47d5ff27..3b6fa9edc9b5 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -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); diff --git a/fs/nfs/super.c b/fs/nfs/super.c index dada09b391c6..eb3a85492396 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -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 */ -- cgit v1.2.3-70-g09d2