From: Trond Myklebust trond.myklebust@hammerspace.com
mainline inclusion from mainline-v5.7-rc1 commit 3c9e502b59fbd243cfac7cc6c875e432d285102a category: bugfix bugzilla: 182252 CVE: NA
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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 Signed-off-by: ChenXiaoSong chenxiaosong2@huawei.com Reviewed-by: Zhang Xiaoxu zhangxiaoxu5@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/nfs/internal.h | 4 +++- fs/nfs/super.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index cc07189a501fa..c3c0b40f163f1 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 fe107348aabe6..48bcdcf4d039e 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -429,6 +429,41 @@ 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 */