GCC Code Coverage Report


Directory: cvmfs/
File: cvmfs/fuse_evict.h
Date: 2025-02-09 02:34:19
Exec Total Coverage
Lines: 4 4 100.0%
Branches: 0 0 -%

Line Branch Exec Source
1 /**
2 * This file is part of the CernVM File System.
3 */
4
5 #ifndef CVMFS_FUSE_EVICT_H_
6 #define CVMFS_FUSE_EVICT_H_
7
8 #include <pthread.h>
9 #include <stdint.h>
10
11 #include "bigvector.h"
12 #include "duplex_fuse.h"
13 #include "gtest/gtest_prod.h"
14 #include "shortstring.h"
15 #include "util/atomic.h"
16 #include "util/concurrency.h"
17 #include "util/single_copy.h"
18
19 namespace glue {
20 class InodeTracker;
21 class DentryTracker;
22 }
23
24 class MountPoint;
25
26 /**
27 * This class can poke all known dentries out of the kernel caches. This allows
28 * for faster remount/reload of the fuse module because caches don't need to
29 * drain out by timeout. If the fuse library doesn't provide
30 * fuse_lowlevel_notify_inval_entry, it falls back to waiting for drainout.
31 *
32 * Evicting entries from the cache must be done from a separate thread to
33 * avoid a deadlock in the fuse callbacks (see Fuse documentation).
34 */
35 class FuseInvalidator : SingleCopy {
36 friend class T_FuseInvalidator; // for T_FuseInvalidator.SetUp()
37 FRIEND_TEST(T_FuseInvalidator, StartStop);
38 FRIEND_TEST(T_FuseInvalidator, InvalidateTimeout);
39 FRIEND_TEST(T_FuseInvalidator, InvalidateOps);
40
41 public:
42 static bool HasFuseNotifyInval();
43
44 /**
45 * Used to track the progress of an "invalidation" request. The invalidator
46 * will evict cache entries for a duration given by the timeout. For very
47 * large caches, active eviction can take longer than the timeout.
48 *
49 * The caller needs to keep Handle active until IsDone() is true;
50 */
51 class Handle : SingleCopy {
52 friend class FuseInvalidator;
53
54 public:
55 explicit Handle(unsigned timeout_s);
56 ~Handle();
57 21 bool IsDone() const { return atomic_read32(status_) == 1; }
58 1 void Reset() { atomic_write32(status_, 0); }
59 void WaitFor();
60
61 private:
62 5 void SetDone() { atomic_cas32(status_, 0, 1); }
63
64 unsigned timeout_s_;
65 atomic_int32 *status_;
66 };
67
68 struct Command {
69 18 virtual ~Command() {}
70 };
71 struct QuitCommand : public Command {};
72 struct InvalInodesCommand : public Command {
73 Handle *handle;
74 };
75 struct InvalDentryCommand : public Command {
76 uint64_t parent_ino;
77 NameString name;
78 };
79
80 FuseInvalidator(MountPoint *mountpoint,
81 void **fuse_channel_or_session,
82 bool fuse_notify_invalidation);
83 ~FuseInvalidator();
84 void Spawn();
85 void InvalidateInodes(Handle *handle);
86
87 void InvalidateDentry(uint64_t parent_ino, const NameString &name);
88
89 private:
90 /**
91 * CONSTRUCTOR ONLY FOR UNITTESTS - mountpoint will illegally be null
92 * ( we do not want to construct a full mountpoint in the unittest )
93 */
94 FuseInvalidator(glue::InodeTracker *inode_tracker,
95 glue::DentryTracker *dentry_tracker,
96 void **fuse_channel_or_session,
97 bool fuse_notify_invalidation);
98 /**
99 * Add one second to the caller-provided timeout to be on the safe side.
100 */
101 static const unsigned kTimeoutSafetyMarginSec; // = 1;
102 /**
103 * If caches are drained out by timeout, set a polling interval.
104 */
105 static const unsigned kCheckTimeoutFreqMs; // = 100;
106 /**
107 * If caches are actively drained out, check every so many operations if the
108 * caches are anyway drained out by timeout.
109 */
110 static const unsigned kCheckTimeoutFreqOps; // = 256
111
112 static void *MainInvalidator(void *data);
113
114 MountPoint *mount_point_;
115
116 glue::InodeTracker *inode_tracker_;
117 glue::DentryTracker *dentry_tracker_;
118 /**
119 * libfuse2 uses struct fuse_chan, libfuse3 uses struct fuse_session
120 */
121 void **fuse_channel_or_session_;
122 bool spawned_;
123 Channel<Command> channel_;
124 pthread_t thread_invalidator_;
125 /**
126 * An invalidation run can take some time. Allow for early cancellation if
127 * thread should be shut down.
128 */
129 atomic_int32 terminated_;
130 BigVector<uint64_t> evict_list_;
131
132 static bool g_fuse_notify_invalidation_;
133 }; // class FuseInvalidator
134
135 #endif // CVMFS_FUSE_EVICT_H_
136