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From: David Howells <dhowells@redhat.com>
To: linux-cachefs@redhat.com
Cc: dhowells@redhat.com, Trond Myklebust <trondmy@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Steve French <sfrench@samba.org>,
	Dominique Martinet <asmadeus@codewreck.org>,
	Jeff Layton <jlayton@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Omar Sandoval <osandov@osandov.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org,
	v9fs-developer@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 32/64] cachefiles: Add some error injection support
Date: Mon, 29 Nov 2021 14:30:47 +0000	[thread overview]
Message-ID: <163819624706.215744.6911916249119962943.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <163819575444.215744.318477214576928110.stgit@warthog.procyon.org.uk>

Add support for injecting ENOSPC or EIO errors.  This needs to be enabled
by CONFIG_CACHEFILES_ERROR_INJECTION=y.  Once enabled, ENOSPC on things
like write and mkdir can be triggered by:

        echo 1 >/proc/sys/cachefiles/error_injection

and EIO can be triggered on most operations by:

        echo 2 >/proc/sys/cachefiles/error_injection

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
---

 fs/cachefiles/Kconfig        |    7 ++++++
 fs/cachefiles/Makefile       |    2 ++
 fs/cachefiles/error_inject.c |   46 ++++++++++++++++++++++++++++++++++++++++++
 fs/cachefiles/internal.h     |   42 +++++++++++++++++++++++++++++++++++++-
 fs/cachefiles/main.c         |   12 +++++++++++
 5 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 fs/cachefiles/error_inject.c

diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig
index 6827b40f7ddc..719faeeda168 100644
--- a/fs/cachefiles/Kconfig
+++ b/fs/cachefiles/Kconfig
@@ -19,3 +19,10 @@ config CACHEFILES_DEBUG
 	  caching on files module.  If this is set, the debugging output may be
 	  enabled by setting bits in /sys/modules/cachefiles/parameter/debug or
 	  by including a debugging specifier in /etc/cachefilesd.conf.
+
+config CACHEFILES_ERROR_INJECTION
+	bool "Provide error injection for cachefiles"
+	depends on CACHEFILES && SYSCTL
+	help
+	  This permits error injection to be enabled in cachefiles whilst a
+	  cache is in service.
diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile
index a7f3e982e249..183fb5f3b8b1 100644
--- a/fs/cachefiles/Makefile
+++ b/fs/cachefiles/Makefile
@@ -6,4 +6,6 @@
 cachefiles-y := \
 	main.o
 
+cachefiles-$(CONFIG_CACHEFILES_ERROR_INJECTION) += error_inject.o
+
 obj-$(CONFIG_CACHEFILES) := cachefiles.o
diff --git a/fs/cachefiles/error_inject.c b/fs/cachefiles/error_inject.c
new file mode 100644
index 000000000000..58f8aec964e4
--- /dev/null
+++ b/fs/cachefiles/error_inject.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Error injection handling.
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/sysctl.h>
+#include "internal.h"
+
+unsigned int cachefiles_error_injection_state;
+
+static struct ctl_table_header *cachefiles_sysctl;
+static struct ctl_table cachefiles_sysctls[] = {
+	{
+		.procname	= "error_injection",
+		.data		= &cachefiles_error_injection_state,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_douintvec,
+	},
+	{}
+};
+
+static struct ctl_table cachefiles_sysctls_root[] = {
+	{
+		.procname	= "cachefiles",
+		.mode		= 0555,
+		.child		= cachefiles_sysctls,
+	},
+	{}
+};
+
+int __init cachefiles_register_error_injection(void)
+{
+	cachefiles_sysctl = register_sysctl_table(cachefiles_sysctls_root);
+	if (!cachefiles_sysctl)
+		return -ENOMEM;
+	return 0;
+
+}
+
+void cachefiles_unregister_error_injection(void)
+{
+	unregister_sysctl_table(cachefiles_sysctl);
+}
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index cff4b2a5f928..1f2fea902d3e 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -64,7 +64,47 @@ struct cachefiles_cache {
 
 
 /*
- * Debug tracing.
+ * error_inject.c
+ */
+#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
+extern unsigned int cachefiles_error_injection_state;
+extern int cachefiles_register_error_injection(void);
+extern void cachefiles_unregister_error_injection(void);
+
+#else
+#define cachefiles_error_injection_state 0
+
+static inline int cachefiles_register_error_injection(void)
+{
+	return 0;
+}
+
+static inline void cachefiles_unregister_error_injection(void)
+{
+}
+#endif
+
+
+static inline int cachefiles_inject_read_error(void)
+{
+	return cachefiles_error_injection_state & 2 ? -EIO : 0;
+}
+
+static inline int cachefiles_inject_write_error(void)
+{
+	return cachefiles_error_injection_state & 2 ? -EIO :
+		cachefiles_error_injection_state & 1 ? -ENOSPC :
+		0;
+}
+
+static inline int cachefiles_inject_remove_error(void)
+{
+	return cachefiles_error_injection_state & 2 ? -EIO : 0;
+}
+
+
+/*
+ * Debug tracing
  */
 extern unsigned cachefiles_debug;
 #define CACHEFILES_DEBUG_KENTER	1
diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c
index 47bc1cc078de..387d42c7185f 100644
--- a/fs/cachefiles/main.c
+++ b/fs/cachefiles/main.c
@@ -36,8 +36,18 @@ MODULE_LICENSE("GPL");
  */
 static int __init cachefiles_init(void)
 {
+	int ret;
+
+	ret = cachefiles_register_error_injection();
+	if (ret < 0)
+		goto error_einj;
+
 	pr_info("Loaded\n");
 	return 0;
+
+error_einj:
+	pr_err("failed to register: %d\n", ret);
+	return ret;
 }
 
 fs_initcall(cachefiles_init);
@@ -48,6 +58,8 @@ fs_initcall(cachefiles_init);
 static void __exit cachefiles_exit(void)
 {
 	pr_info("Unloading\n");
+
+	cachefiles_unregister_error_injection();
 }
 
 module_exit(cachefiles_exit);



  parent reply	other threads:[~2021-11-29 14:33 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-29 14:22 [PATCH 00/64] fscache, cachefiles: Rewrite David Howells
2021-11-29 14:22 ` [PATCH 01/64] fscache, cachefiles: Disable configuration David Howells
2021-11-29 14:22 ` [PATCH 02/64] cachefiles: Delete the cachefiles driver pending rewrite David Howells
2021-11-29 14:23 ` [PATCH 03/64] fscache: Remove the contents of the fscache driver, " David Howells
2021-11-29 14:23 ` [PATCH 04/64] netfs: Display the netfs inode number in the netfs_read tracepoint David Howells
2021-11-29 14:23 ` [PATCH 05/64] netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space David Howells
2021-11-29 14:24 ` [PATCH 06/64] fscache: Introduce new driver David Howells
2021-11-29 14:24 ` [PATCH 07/64] fscache: Implement a hash function David Howells
2021-11-29 14:24 ` [PATCH 08/64] fscache: Implement cache registration David Howells
2021-11-29 14:24 ` [PATCH 09/64] fscache: Implement volume registration David Howells
2021-11-29 14:25 ` [PATCH 10/64] fscache: Implement cookie registration David Howells
2021-11-29 14:25 ` [PATCH 11/64] fscache: Implement cache-level access helpers David Howells
2021-11-29 14:25 ` [PATCH 12/64] fscache: Implement volume-level " David Howells
2021-11-29 14:25 ` [PATCH 13/64] fscache: Implement cookie-level " David Howells
2021-11-29 14:26 ` [PATCH 14/64] fscache: Implement functions add/remove a cache David Howells
2021-11-29 14:26 ` [PATCH 15/64] fscache: Provide and use cache methods to lookup/create/free a volume David Howells
2021-11-29 14:26 ` [PATCH 16/64] fscache: Add a function for a cache backend to note an I/O error David Howells
2021-11-29 14:26 ` [PATCH 17/64] fscache: Implement simple cookie state machine David Howells
2021-11-29 14:26 ` [PATCH 18/64] fscache: Implement cookie user counting and resource pinning David Howells
2021-11-29 14:27 ` [PATCH 19/64] fscache: Implement cookie invalidation David Howells
2021-11-29 14:27 ` [PATCH 20/64] fscache: Provide a means to begin an operation David Howells
2021-11-29 14:28 ` [PATCH 21/64] fscache: Count data storage objects in a cache David Howells
2021-11-29 14:28 ` [PATCH 22/64] fscache: Provide read/write stat counters for the cache David Howells
2021-11-29 14:28 ` [PATCH 23/64] fscache: Provide a function to let the netfs update its coherency data David Howells
2021-11-29 14:28 ` [PATCH 24/64] netfs: Pass more information on how to deal with a hole in the cache David Howells
2021-12-06 11:42   ` JeffleXu
2021-12-09 16:49   ` David Howells
2021-11-29 14:28 ` [PATCH 25/64] fscache: Implement raw I/O interface David Howells
2021-11-29 14:29 ` [PATCH 26/64] fscache: Implement higher-level write " David Howells
2021-11-29 14:29 ` [PATCH 27/64] vfs, fscache: Implement pinning of cache usage for writeback David Howells
2021-11-29 14:29 ` [PATCH 28/64] fscache: Provide a function to note the release of a page David Howells
2021-11-29 14:30 ` [PATCH 29/64] fscache: Provide a function to resize a cookie David Howells
2021-11-29 14:30 ` [PATCH 30/64] cachefiles: Introduce rewritten driver David Howells
2021-11-29 14:30 ` [PATCH 31/64] cachefiles: Define structs David Howells
2021-11-29 14:30 ` David Howells [this message]
2021-11-29 14:30 ` [PATCH 33/64] cachefiles: Add a couple of tracepoints for logging errors David Howells
2021-11-29 14:31 ` [PATCH 34/64] cachefiles: Add cache error reporting macro David Howells
2021-11-29 14:31 ` [PATCH 35/64] cachefiles: Add security derivation David Howells
2021-11-29 14:31 ` [PATCH 36/64] cachefiles: Register a miscdev and parse commands over it David Howells
2021-11-29 14:31 ` [PATCH 37/64] cachefiles: Provide a function to check how much space there is David Howells
2021-11-29 14:31 ` [PATCH 38/64] vfs, cachefiles: Mark a backing file in use with an inode flag David Howells
2021-11-29 14:31 ` [PATCH 39/64] cachefiles: Implement a function to get/create a directory in the cache David Howells
2021-11-29 14:32 ` [PATCH 40/64] cachefiles: Implement cache registration and withdrawal David Howells
2021-11-29 14:32 ` [PATCH 41/64] cachefiles: Implement volume support David Howells
2021-11-29 14:33 ` [PATCH 42/64] cachefiles: Add tracepoints for calls to the VFS David Howells
2021-11-29 14:33 ` [PATCH 43/64] cachefiles: Implement object lifecycle funcs David Howells
2021-11-29 14:33 ` [PATCH 44/64] cachefiles: Implement key to filename encoding David Howells
2021-12-01  5:46   ` JeffleXu
2021-12-01  8:29   ` David Howells
2021-11-29 14:33 ` [PATCH 45/64] cachefiles: Implement metadata/coherency data storage in xattrs David Howells
2021-11-29 14:33 ` [PATCH 46/64] cachefiles: Mark a backing file in use with an inode flag David Howells
2021-11-29 14:33 ` [PATCH 47/64] cachefiles: Implement culling daemon commands David Howells
2021-11-29 14:34 ` [PATCH 48/64] cachefiles: Implement backing file wrangling David Howells
2021-11-29 14:34 ` [PATCH 49/64] cachefiles: Implement begin and end I/O operation David Howells
2021-11-29 14:34 ` [PATCH 50/64] cachefiles: Implement cookie resize for truncate David Howells
2021-11-29 14:34 ` [PATCH 51/64] cachefiles: Implement the I/O routines David Howells
2021-11-30 16:15   ` Nathan Chancellor
2021-11-30 21:05   ` David Howells
2021-11-29 14:34 ` [PATCH 52/64] cachefiles: Allow cachefiles to actually function David Howells
2021-11-29 14:35 ` [PATCH 53/64] fscache, cachefiles: Display stats of no-space events David Howells
2021-11-29 14:35 ` [PATCH 54/64] fscache, cachefiles: Display stat of culling events David Howells
2021-11-29 14:36 ` [PATCH 55/64] afs: Handle len being extending over page end in write_begin/write_end David Howells
2021-11-29 14:36 ` [PATCH 56/64] afs: Fix afs_write_end() to handle len > page size David Howells
2021-11-29 14:36 ` [PATCH 57/64] afs: Convert afs to use the new fscache API David Howells
2021-11-29 14:37 ` [PATCH 58/64] afs: Copy local writes to the cache when writing to the server David Howells
2021-11-29 14:37 ` [PATCH 59/64] afs: Skip truncation on the server of data we haven't written yet David Howells
2021-11-29 14:37 ` [PATCH 60/64] 9p: Use fscache indexing rewrite and reenable caching David Howells
2021-11-29 14:37 ` [PATCH 61/64] 9p: Copy local writes to the cache when writing to the server David Howells
2021-11-29 14:38 ` [PATCH 62/64] nfs: Convert to new fscache volume/cookie API David Howells
2021-11-29 14:38 ` [PATCH 63/64] cifs: Support fscache indexing rewrite (untested) David Howells
2021-11-29 14:38 ` [PATCH 64/64] fscache: Rewrite documentation David Howells
2021-11-29 18:12 ` [PATCH 00/64] fscache, cachefiles: Rewrite Linus Torvalds
2021-11-29 21:40 ` [PATCH 35/64] cachefiles: Add security derivation David Howells

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