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33cba85922
fscache_cookie_put() accesses the cookie it has just put inside the
tracepoint that monitors the change - but this is something it's not
allowed to do if we didn't reduce the count to zero.
Fix this by dropping most of those values from the tracepoint and grabbing
the cookie debug ID before doing the dec.
Also take the opportunity to switch over the usage and where arguments on
the tracepoint to put the reason last.
Fixes: a18feb5576 ("fscache: Add tracepoints")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431203107.2908479.3259582550347000088.stgit@warthog.procyon.org.uk/
75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* FS-Cache netfs (client) registration
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*
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* Copyright (C) 2008 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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#define FSCACHE_DEBUG_LEVEL COOKIE
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "internal.h"
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/*
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* register a network filesystem for caching
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*/
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int __fscache_register_netfs(struct fscache_netfs *netfs)
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{
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struct fscache_cookie *candidate, *cookie;
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_enter("{%s}", netfs->name);
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/* allocate a cookie for the primary index */
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candidate = fscache_alloc_cookie(&fscache_fsdef_index,
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&fscache_fsdef_netfs_def,
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netfs->name, strlen(netfs->name),
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&netfs->version, sizeof(netfs->version),
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netfs, 0);
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if (!candidate) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;
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/* check the netfs type is not already present */
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cookie = fscache_hash_cookie(candidate);
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if (!cookie)
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goto already_registered;
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if (cookie != candidate) {
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trace_fscache_cookie(candidate->debug_id, 1, fscache_cookie_discard);
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fscache_free_cookie(candidate);
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}
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fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
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atomic_inc(&cookie->parent->n_children);
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netfs->primary_index = cookie;
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pr_notice("Netfs '%s' registered for caching\n", netfs->name);
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trace_fscache_netfs(netfs);
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_leave(" = 0");
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return 0;
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already_registered:
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fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
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_leave(" = -EEXIST");
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return -EEXIST;
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}
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EXPORT_SYMBOL(__fscache_register_netfs);
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/*
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* unregister a network filesystem from the cache
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* - all cookies must have been released first
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*/
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void __fscache_unregister_netfs(struct fscache_netfs *netfs)
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{
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_enter("{%s.%u}", netfs->name, netfs->version);
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fscache_relinquish_cookie(netfs->primary_index, NULL, false);
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pr_notice("Netfs '%s' unregistered from caching\n", netfs->name);
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_leave("");
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}
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EXPORT_SYMBOL(__fscache_unregister_netfs);
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