From 4a06825839889cc1756d0dd8a52d6b1071ee0263 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 11 May 2015 14:02:25 -0400 Subject: SUNRPC: Transport fault injection It has been exceptionally useful to exercise the logic that handles local immediate errors and RDMA connection loss. To enable developers to test this regularly and repeatably, add logic to simulate connection loss every so often. Fault injection is disabled by default. It is enabled with $ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect where "xxx" is a large positive number of transport method calls before a disconnect. A value of several thousand is usually a good number that allows reasonable forward progress while still causing a lot of connection drops. These hooks are disabled when SUNRPC_DEBUG is turned off. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- net/sunrpc/debugfs.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) (limited to 'net/sunrpc/debugfs.c') diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c index 82962f7e6e88..7cc1b8a6ef6d 100644 --- a/net/sunrpc/debugfs.c +++ b/net/sunrpc/debugfs.c @@ -10,9 +10,12 @@ #include "netns.h" static struct dentry *topdir; +static struct dentry *rpc_fault_dir; static struct dentry *rpc_clnt_dir; static struct dentry *rpc_xprt_dir; +unsigned int rpc_inject_disconnect; + struct rpc_clnt_iter { struct rpc_clnt *clnt; loff_t pos; @@ -257,6 +260,8 @@ rpc_xprt_debugfs_register(struct rpc_xprt *xprt) debugfs_remove_recursive(xprt->debugfs); xprt->debugfs = NULL; } + + atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect); } void @@ -266,11 +271,78 @@ rpc_xprt_debugfs_unregister(struct rpc_xprt *xprt) xprt->debugfs = NULL; } +static int +fault_open(struct inode *inode, struct file *filp) +{ + filp->private_data = kmalloc(128, GFP_KERNEL); + if (!filp->private_data) + return -ENOMEM; + return 0; +} + +static int +fault_release(struct inode *inode, struct file *filp) +{ + kfree(filp->private_data); + return 0; +} + +static ssize_t +fault_disconnect_read(struct file *filp, char __user *user_buf, + size_t len, loff_t *offset) +{ + char *buffer = (char *)filp->private_data; + size_t size; + + size = sprintf(buffer, "%u\n", rpc_inject_disconnect); + return simple_read_from_buffer(user_buf, len, offset, buffer, size); +} + +static ssize_t +fault_disconnect_write(struct file *filp, const char __user *user_buf, + size_t len, loff_t *offset) +{ + char buffer[16]; + + len = min(len, sizeof(buffer) - 1); + if (copy_from_user(buffer, user_buf, len)) + return -EFAULT; + buffer[len] = '\0'; + if (kstrtouint(buffer, 10, &rpc_inject_disconnect)) + return -EINVAL; + return len; +} + +static const struct file_operations fault_disconnect_fops = { + .owner = THIS_MODULE, + .open = fault_open, + .read = fault_disconnect_read, + .write = fault_disconnect_write, + .release = fault_release, +}; + +static struct dentry * +inject_fault_dir(struct dentry *topdir) +{ + struct dentry *faultdir; + + faultdir = debugfs_create_dir("inject_fault", topdir); + if (!faultdir) + return NULL; + + if (!debugfs_create_file("disconnect", S_IFREG | S_IRUSR, faultdir, + NULL, &fault_disconnect_fops)) + return NULL; + + return faultdir; +} + void __exit sunrpc_debugfs_exit(void) { debugfs_remove_recursive(topdir); topdir = NULL; + rpc_fault_dir = NULL; rpc_clnt_dir = NULL; rpc_xprt_dir = NULL; } @@ -282,6 +354,10 @@ sunrpc_debugfs_init(void) if (!topdir) return; + rpc_fault_dir = inject_fault_dir(topdir); + if (!rpc_fault_dir) + goto out_remove; + rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir); if (!rpc_clnt_dir) goto out_remove; @@ -294,5 +370,6 @@ sunrpc_debugfs_init(void) out_remove: debugfs_remove_recursive(topdir); topdir = NULL; + rpc_fault_dir = NULL; rpc_clnt_dir = NULL; } -- cgit v1.2.3