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Register a misc device with which to talk to the daemon. The misc device holds a cache set up through it around and closing the device kills the cache. cachefilesd communicates with the kernel by passing it single-line text commands. Parse these and use them to parameterise the cache state. This does not implement the command to actually bring a cache online. That's left for later. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819628388.215744.17712097043607299608.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906929128.143852.14065207858943654011.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967139085.1823006.3514846391807454287.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021538400.640689.9172006906288062041.stgit@warthog.procyon.org.uk/ # v4
78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Network filesystem caching backend to use cache files on a premounted
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* filesystem
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*
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* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/completion.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/statfs.h>
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#include <linux/sysctl.h>
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#include <linux/miscdevice.h>
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#include <linux/netfs.h>
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#include <trace/events/netfs.h>
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#define CREATE_TRACE_POINTS
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#include "internal.h"
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unsigned cachefiles_debug;
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module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
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MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
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MODULE_DESCRIPTION("Mounted-filesystem based cache");
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MODULE_AUTHOR("Red Hat, Inc.");
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MODULE_LICENSE("GPL");
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static struct miscdevice cachefiles_dev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "cachefiles",
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.fops = &cachefiles_daemon_fops,
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};
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/*
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* initialise the fs caching module
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*/
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static int __init cachefiles_init(void)
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{
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int ret;
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ret = cachefiles_register_error_injection();
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if (ret < 0)
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goto error_einj;
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ret = misc_register(&cachefiles_dev);
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if (ret < 0)
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goto error_dev;
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pr_info("Loaded\n");
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return 0;
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error_dev:
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cachefiles_unregister_error_injection();
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error_einj:
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pr_err("failed to register: %d\n", ret);
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return ret;
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}
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fs_initcall(cachefiles_init);
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/*
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* clean up on module removal
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*/
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static void __exit cachefiles_exit(void)
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{
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pr_info("Unloading\n");
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misc_deregister(&cachefiles_dev);
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cachefiles_unregister_error_injection();
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}
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module_exit(cachefiles_exit);
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