Commit Graph

4836 Commits

Author SHA1 Message Date
Matthias Sohn 38198972d4 Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Bazel: Fix warning about deprecated lib.bzl
  Format lib/BUILD with buildifier
  Bazel: Add fixes for --incompatible_load_java_rules_from_bzl
  Bazel: Bump minimum supported version to 0.29.0
  Bazel: Bump skylib library version to 0.8.0
  Use bazelisk to switch between used bazel version
  Bazel: Require minimum bazel version 0.17.1
  Fix wrong placeholder index in error message packInaccessible
  JGitText: Remove unused externalized strings
  RepoText: Remove unused externalized string
  CLI: Remove unused externalized strings

Change-Id: Iea37a8e39e9d4872dc607c9222dcf191ce4e4757
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-07 12:16:42 +02:00
David Pursehouse 85cea8c583 Bazel: Add fixes for --incompatible_load_java_rules_from_bzl
Change-Id: I24746335db132bf20f400cb3db400737596d4542
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
2019-09-07 15:36:11 +09:00
Matthias Sohn 185dc84623 Fix wrong placeholder index in error message packInaccessible
See: https://www.eclipse.org/lists/jgit-dev/msg03850.html
Change-Id: I0e121a2b7ac399f4a663fa49ab330d27363e9a55
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-07 01:19:07 +02:00
David Pursehouse 8792743c51 JGitText: Remove unused externalized strings
Change-Id: I995d7a1b6ab2866221eee9f5cb828b97192daf4a
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
2019-09-07 01:19:07 +02:00
David Pursehouse 689474248c RepoText: Remove unused externalized string
Change-Id: Ida47637f54afdb76513be9b04aae32107567d4e3
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
2019-09-07 01:19:06 +02:00
Matthias Sohn aa62f191d0 Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Prepare 5.1.12-SNAPSHOT builds
  JGit v5.1.11.201909031202-r
  Prepare 4.11.10-SNAPSHOT builds
  JGit v4.11.9.201909030838-r
  Bazel: Update bazlets to the latest master revision
  Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: Iac5dc9683cea97db04d20f27c10f2e103d3ae7b5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-04 00:08:21 +02:00
Matthias Sohn c8e42ca3ba Prepare 5.1.12-SNAPSHOT builds
Change-Id: I353ac3f23024063722abc7340bc9a6df3c615741
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 22:56:39 +02:00
Matthias Sohn 002f1628c6 JGit v5.1.11.201909031202-r
Change-Id: I288acf670160b9bcd2d04f572a902b5838b4d4f8
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 18:01:55 +02:00
Matthias Sohn 7aec793266 Merge branch 'stable-5.0' into stable-5.1
* stable-5.0:
  Prepare 4.11.10-SNAPSHOT builds
  JGit v4.11.9.201909030838-r
  Bazel: Update bazlets to the latest master revision
  Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: I172136a031ff0730e575327cafb3527c9650a71d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 17:40:19 +02:00
Matthias Sohn c31879ac4e Merge branch 'stable-4.11' into stable-5.0
* stable-4.11:
  Prepare 4.11.10-SNAPSHOT builds
  JGit v4.11.9.201909030838-r
  Bazel: Update bazlets to the latest master revision
  Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: Ifb6a4dbea2f48fd2ffa66eb737d61920aefedfbd
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 15:59:39 +02:00
Matthias Sohn 261881055d Prepare 4.11.10-SNAPSHOT builds
Change-Id: Ic98bd87d96ce627d38e1ecc2c3cb28b517ab489e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 14:49:20 +02:00
Matthias Sohn 9a2deb2049 JGit v4.11.9.201909030838-r
Change-Id: Ie60468569074197d49e19cbd0ffaedfe88f3d74e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 14:37:49 +02:00
Matthias Sohn b0fd436c62 Merge branch 'stable-4.10' into stable-4.11
* stable-4.10:
  Bazel: Update bazlets to the latest master revision
  Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: If672b4f0c350f4e8ff7e1e706485cffd8137236d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 14:28:49 +02:00
Matthias Sohn b525036e58 Merge branch 'stable-4.9' into stable-4.10
* stable-4.9:
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: Id5bf44645655fca40ad22bb1f1ad20a7c2e8f6db
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 14:20:37 +02:00
Han-Wen Nienhuys 0e3d4a273f BatchRefUpdate: repro racy atomic update, and fix it
PackedBatchRefUpdate was creating a new packed-refs list that was
potentially unsorted. This would be papered over when the list was
read back from disk in parsePackedRef, which detects unsorted ref
lists on reading, and sorts them. However, the BatchRefUpdate also
installed the new (unsorted) list in-memory in
RefDirectory#packedRefs.

With the timestamp granularity code committed to stable-5.1, we can
more often accurately decide that the packed-refs file is clean, and
will return the erroneous unsorted data more often. Unluckily timed
delays also cause the file to be clean, hence this problem was
exacerbated under load.

The symptom is that refs added by a BatchRefUpdate would stop being
visible directly after they were added. In particular, the Gerrit
integration tests uses BatchRefUpdate in its setup for creating the
Admin group, and then tries to read it out directly afterward.

The tests recreates one failure case. A better approach would be to
revise RefList.Builder, so it detects out-of-order lists and
automatically sorts them.

Fixes https://bugs.eclipse.org/bugs/show_bug.cgi?id=548716 and
https://bugs.chromium.org/p/gerrit/issues/detail?id=11373.

Bug: 548716
Change-Id: I613c8059964513ce2370543620725b540b3cb6d1
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 10:37:30 +02:00
Matthias Sohn 7e0cd90cf7 Silence API warnings
Change-Id: I27fd62de51ca0eedcc7e2e256487bda1e18bce8a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-09-03 02:55:37 +02:00
Jonathan Nieder 60283a58a7 Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Return a new instance from openSystemConfig and openUserConfig

Change-Id: I93afa16b14e3e2d127705e3378fb703d6c329694
Signed-off-by: Jonathan Nieder <jrn@google.com>
2019-08-29 18:15:23 -07:00
Matthias Sohn af0296b42c Return a new instance from openSystemConfig and openUserConfig
Move the handling of cached user and system config to getSystemConfig
and getUserConfig methods and revert the implementation of
openSystemConfig and openUserConfig to the old stateless
implementation.

This ensures the open methods respect the passed-in parent config, which
may be different on each invocation. Additionally, returning a new
instance matches the behavior of the previous implementation of the
default system reader, which downstream callers may be depending on.

Move the implementation of the new caching methods getSystemConfig and
getUserConfig up to SystemReader. This avoids that we break the ABI for
subclasses of SystemReader.

Also see [1] which fixed a similar problem with Gerrit's custom
SystemReader.

[1] https://gerrit-review.googlesource.com/c/gerrit/+/225458

Change-Id: If54a2491932d8fc914d4649cb73c9e837c5b8ad0
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-30 02:34:13 +02:00
Matthias Sohn d999d12ad0 Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Prepare 5.1.11-SNAPSHOT builds
  JGit v5.1.10.201908230655-r
  Use AtomicReferences to cache user and system level configs
  Fix copy-paste typo in CloneCommand#cleanup

Change-Id: Ie383633de334e65901ed4c6deb2d59cfcce98e16
2019-08-23 16:00:38 +02:00
Matthias Sohn 418722df34 Prepare 5.1.11-SNAPSHOT builds
Change-Id: I8608580424d0e523dcace63f83ae530ba78dbb15
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-23 15:55:45 +02:00
Matthias Sohn 1c44bf8caf JGit v5.1.10.201908230655-r
Change-Id: I68d15ebd6054bdeaf62e14cddb87724828db7943
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-23 13:38:56 +02:00
Matthias Sohn d67fe38915 Use AtomicReferences to cache user and system level configs
This ensures that only one instance of user and one instance of system
config is set.

Change-Id: Idd00150f91d2d40af79499dd7bf8ad5940f87c4e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-23 05:07:05 -04:00
Adrien Bustany 28553c189c Fix copy-paste typo in CloneCommand#cleanup
deleteChildren was called on directory instead of gitDir, leading to a
potential null pointer exception if the git directory existed initially.

Bug: 550340
Change-Id: Iafc3b2961253a99862a59e81c7371f7bc564b412
Signed-off-by: Adrien Bustany <adrien-xx-eclipse@bustany.org>
2019-08-23 08:45:55 +09:00
Matthias Sohn 7ac3a63e7f Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Add missing @since tag on FileTreeIterator#getLastModifiedInstant
  Prepare 5.1.10-SNAPSHOT builds
  JGit v5.1.9.201908210455-r
  Avoid sign extension when comparing mtime with Instant#getEpochSecond
  Fix deprecation in DirCache caused by Instant based DirCacheEntry

Change-Id: Id824c0b8b14dad5947ae9da1f90c3471e07b400f
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 12:02:33 +02:00
Matthias Sohn e80a62e226 Add missing @since tag on FileTreeIterator#getLastModifiedInstant
Change-Id: I809399e6a71e0079d2f0007b0d3f00b531d451bb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 11:52:20 +02:00
Matthias Sohn edc67125b7 Prepare 5.1.10-SNAPSHOT builds
Change-Id: If10afc8e663299a15db8c5fd0574fb51bf7e7ae9
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 11:51:41 +02:00
Matthias Sohn 38adb548c3 JGit v5.1.9.201908210455-r
Change-Id: Iaade207292acb8b27e01aca7e1af97ad7db1e854
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 10:52:10 +02:00
Matthias Sohn c130e5e708 Avoid sign extension when comparing mtime with Instant#getEpochSecond
Ensure we use the same type when comparing seconds since the epoch.

This does not prevent that in 2038 timestamps in seconds since the epoch
stored in a 32 bit integer will overflow. Integer.MAX_VALUE translates
to 2038-01-19T03:14:07Z. After this date we'll have an issue since we
store seconds since the epoch in a 32 bit integer in some places.

Bug: 319142
Change-Id: If0c03003d40b480f044686e2f7a2f62c9f4e2fe1
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 00:29:45 +02:00
Michael Keppler 6cb21049d7 Fix deprecation in DirCache caused by Instant based DirCacheEntry
Replace the two int variables smudge_s and smudge_ns by an Instant and
use the new method DirCacheEntry.mightBeRacilyClean(Instant).

Change-Id: Id70adbb0856a64909617acf65da1bae8e2ae934a
Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-21 00:07:49 +02:00
Matthias Sohn 0eea7368e2 Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Fix NPE in RebaseTodoFile#parseComments
  Fix NPE in ObjectIdOwnerMap#get
  Fix NPE in CommitOnlyTest#getHead
  FileUtils#lastModifiedInstant should not log error if path doesn't exist
  Cache user global and system-wide git configurations
  Avoid setup and saving FileStoreAttributes compete for ~/.gitconfig lock
  Add missing dependencies for running FS_POSIXTest in Eclipse
  Fix javadoc for SystemReader#getInstance
  Improve retry handling when saving FileStoreAttributes fails
  Ensure FSTest uses MockSystemReader
  Make supportsAtomicCreateNewFile return true as default
  Update orbit to R20190602212107-2019-06 to enable backports from master
  Handle InvalidPathException in FS_POSIX#createNewFileAtomic
  Ensure root cause of lock creation failures is logged
  Implement toString in MockSystemReader and MockConfig
  LocalDiskRefTreeDatabaseTest shall use MockSystemReader
  Ensure LocalDiskRepositoryTestCase#setup fully uses MockSystemReader
  Ensure we use MockSystemReader in tests
  Override FileBasedConfig's save method in MockConfig
  Remove FileBasedConfig.load(boolean) introduced in d45219ba
  Disable debug log for FS in org.eclipse.jgit.test
  Bazel: enable logging for tests in org.eclipse.jgit.test
  LockFile: log exception if creation of lock file failed
  Stop using deprecated Constants.CHARACTER_ENCODING

Change-Id: I48c585f3c9287be7d6ddb6b01a1955444e13fa31
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-19 18:30:35 +02:00
Matthias Sohn 86a567f615 Fix NPE in RebaseTodoFile#parseComments
Change-Id: I5487f3c2609eaf2a0ddf71ebb2f6c9701fb7600c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-19 10:16:23 +02:00
Matthias Sohn a4216e5382 Fix NPE in ObjectIdOwnerMap#get
Change-Id: I3812961a27ac410d610ef50c73a28f21bb05ae79
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-18 11:59:54 +02:00
Matthias Sohn 31356f5d18 FileUtils#lastModifiedInstant should not log error if path doesn't exist
Change-Id: Id8447735beb24becb41612d3d29d5351f8273d22
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-18 11:59:54 +02:00
Matthias Sohn f383206ace Cache user global and system-wide git configurations
So far the git configuration and the system wide git configuration were
always reloaded when jgit accessed these global configuration files to
access global configuration options which are not in the context of a
single git repository. Cache these configurations in SystemReader and
only reload them if their file metadata observed using FileSnapshot
indicates a modification.

Change-Id: I092fe11a5d95f1c5799273cacfc7a415d0b7786c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>
2019-08-18 11:47:26 +02:00
Matthias Sohn b51bb4f7bd Fix javadoc for SystemReader#getInstance
The existing javadoc was copied from another method and not adapted.

Change-Id: I39a7e5d719b2c379de9bd1a4710a55a73700c6f0
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-16 16:51:45 +02:00
Matthias Sohn 2d84bb4341 Improve retry handling when saving FileStoreAttributes fails
- fix handling of interrupts in FileStoreAttributes#saveToConfig
- increase retry wait time to 100ms
- don't wait after last retry
- dont retry if failure is caused by another exception than
LockFailedException

Change-Id: I108c012717d2bcce71f2c6cb9cf0879de704ebc2
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-13 08:33:32 +02:00
Vishal Devgire 9b4a55c0b6 Make supportsAtomicCreateNewFile return true as default
The method org.eclipse.jgit.util.FS.supportsAtomicCreateNewFile()
should default to true as mentioned in docs [1]

org.eclipse.jgit.util.FS_POSIX.supportsAtomicCreateNewFile() method
will set the value to false if the git config
core.supportsatomiccreatenewfile is not set.

It should default to true if the configuration is undefined.

[1]
4169a95a65/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java (L372)

Bug: 544164
Change-Id: I16ccf989a89da2cf4975c200b3228b25ba4c0d55
Signed-off-by: Vishal Devgire <vishaldevgire@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-12 14:35:06 +02:00
Matthias Sohn 6ef225c519 Handle InvalidPathException in FS_POSIX#createNewFileAtomic
Bug: 547400
Change-Id: Ic3541e360a2968ba3532a3d3fa4828b0d0463c02
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-12 12:18:16 +02:00
Matthias Sohn cc29da8e0f Ensure root cause of lock creation failures is logged
Change-Id: I91cdf1e085a29c0aabd6d22c6ebe848b2d75f42c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-12 12:17:11 +02:00
Matthias Sohn a7338dd1e5 Remove FileBasedConfig.load(boolean) introduced in d45219ba
We can't add this method to the super class StoredConfig since that
abstracts from filesystem storage. MockSystemReader.MockConfig is a
StoredConfig and is also used by tests for dfs based storage. Hence
remove this leaky abstraction.

This implies we always use the fallback FileStoreAttributes which means
a config file modification is considered racy within the first 2
seconds. This should not be an issue since typically configs change
rarely and re-reading a config within the racy period is relatively
cheap since configs are small.

Change-Id: Ia2615addc24a7cadf3c566ee842c6f4f07e159a5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-10 23:57:21 +02:00
Matthias Sohn 42000a71e3 LockFile: log exception if creation of lock file failed
Change-Id: I4de75d12ec9e61193494916307289378cdb6220e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-10 00:57:04 +02:00
David Pursehouse ad02a7cbad Stop using deprecated Constants.CHARACTER_ENCODING
Change-Id: I105b8a05bc64f249879a0795a059958553cc60c6
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
2019-08-09 12:11:41 +09:00
Matthias Sohn 0046b2a8fe Merge branch 'stable-5.1' into stable-5.2
* stable-5.1:
  Fix OpenSshConfigTest#config
  FileSnapshot: fix bug with timestamp thresholding
  In LockFile#waitForStatChange wait in units of file time resolution
  Cache FileStoreAttributeCache per directory
  Fix FileSnapshot#save(long) and FileSnapshot#save(Instant)
  Persist minimal racy threshold and allow manual configuration
  Measure minimum racy interval to auto-configure FileSnapshot
  Reuse FileUtils to recursively delete files created by tests
  Fix FileAttributeCache.toString()
  Add test for racy git detection in FileSnapshot
  Repeat RefDirectoryTest.testGetRef_DiscoversModifiedLoose 100 times
  Fix org.eclipse.jdt.core.prefs of org.eclipse.jgit.junit
  Add missing javadoc in org.eclipse.jgit.junit
  Enhance RepeatRule to report number of failures at the end
  Fix FileSnapshotTests for filesystem with high timestamp resolution
  Retry deleting test files in FileBasedConfigTest
  Measure filesystem timestamp resolution already in test setup
  Refactor FileSnapshotTest to use NIO APIs
  Measure stored timestamp resolution instead of time to touch file
  Handle CancellationException in FileStoreAttributeCache
  Fix FileSnapshot#saveNoConfig
  Use Instant for smudge time in DirCache and DirCacheEntry
  Use Instant instead of milliseconds for filesystem timestamp handling
  Workaround SecurityException in FS#getFsTimestampResolution
  Fix NPE in FS$FileStoreAttributeCache.getFsTimestampResolution
  FS: ignore AccessDeniedException when measuring timestamp resolution
  Add debug trace for FileSnapshot
  Use FileChannel.open to touch file and set mtime to now
  Persist filesystem timestamp resolution and allow manual configuration
  Increase bazel timeout for long running tests
  Bazel: Fix lint warning flagged by buildifier
  Update bazlets to latest version
  Bazel: Add missing dependencies for ArchiveCommandTest
  Bazel: Remove FileTreeIteratorWithTimeControl from BUILD file
  Add support for nanoseconds and microseconds for Config#getTimeUnit
  Optionally measure filesystem timestamp resolution asynchronously
  Delete unused FileTreeIteratorWithTimeControl
  FileSnapshot#equals: consider UNKNOWN_SIZE
  Timeout measuring file timestamp resolution after 2 seconds
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Deprecate Constants.CHARACTER_ENCODING in favor of StandardCharsets.UTF_8
  Fix non-deterministic hash of archives created by ArchiveCommand
  Update Maven plugins ecj, plexus, error-prone
  Update Maven plugins and cleanup Maven warnings
  Make inner classes static where possible
  Fix API problem filters

Change-Id: Ia57385b2a60f48a5317c8d723721c235d7043a84
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-08 11:54:56 +02:00
Han-Wen Nienhuys e60b9e1879 FileSnapshot: fix bug with timestamp thresholding
Increase the safety factor to 2.5x for extra safety if max of measured
timestamp resolution and measured minimal racy threshold is < 100ms, use
1.25 otherwise since for large filesystem resolution values the
influence of finite resolution of the system clock should be negligible.

Before, not yet using the newly introduced minRacyThreshold measurement,
the threshold was 1.1x FS resolution, and we could issue the
following sequence of events,

  start
  create-file
  read-file (currentTime)
  end

which had the following timestamps:

  create-file 1564589081998
  start 1564589082002
  read 1564589082003
  end 1564589082004

In this case, the difference between create-file and read is 5ms,
which exceeded the 4ms FS resolution, even though the events together
took just 2ms of runtime.

Reproduce with:
  bazel test --runs_per_test=100 \
    //org.eclipse.jgit.test:org_eclipse_jgit_internal_storage_file_FileSnapshotTest

The file system timestamp resolution is 4ms in this case.

This code assumes that the kernel and the JVM use the same clock that
is synchronized with the file system clock. This seems plausible,
given the resolution of System.currentTimeMillis() and the latency for
a gettimeofday system call (typically ~1us), but it would be good to
justify this with specifications.

Also cover a source of flakiness: if the test runs under extreme load,
then we could have

  start
  create-file
  <long delay>
  read
  end

which would register as an unmodified file. Avoid this by skipping the
test if end-start is too big.

[msohn]:
- downported from master to stable-5.1
- skip test if resolution is below 10ms
- adjust safety factor to 1.25 for resolutions above 100ms

Change-Id: I87d2cf035e01c44b7ba8364c410a860aa8e312ef
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-07 13:56:08 +02:00
Matthias Sohn 3b368d5578 In LockFile#waitForStatChange wait in units of file time resolution
Since we now measure file time resolution we can use it to replace the
hard coded wait time of 25ms. FileSnapshot#equals will return true until
the mtime of the old (o) and the new FileSnapshot (n) differ by at least
one  file time resolution.

Change-Id: Icb713a80ce9eb929242ed083406bfb6650c72223
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-07 13:21:39 +02:00
Matthias Sohn 6857138e19 Cache FileStoreAttributeCache per directory
Cache FileStoreAttributeCache entries since looking up FileStore for a
file may be expensive on some platforms.

Implement a simple LRU cache based on ConcurrentHashMap using a simple
long counter to order access to cache entries.

Change-Id: I4881fa938ad2f17712c05da857838073a2fc4ddb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Marc Strapetz <marc.strapetz@syntevo.com>
Also-By: Marc Strapetz <marc.strapetz@syntevo.com>
2019-08-06 14:54:39 +02:00
Matthias Sohn 275f3da783 Fix FileSnapshot#save(long) and FileSnapshot#save(Instant)
Use the fallback timestamp resolution as already described in the
javadoc of these methods. Using zero file timestamp resolution doesn't
make sense.

Change-Id: Iaad2a0f99c3be3678e94980a0a368181b6aed38c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-06 14:54:39 +02:00
Matthias Sohn d45219baac Persist minimal racy threshold and allow manual configuration
To enable persisting the minimal racy threshold per FileStore add a
new config option to the user global git configuration:

- Config section is "filesystem"
- Config subsection is concatenation of
  - Java vendor (system property "java.vendor")
  - Java version (system property "java.version")
  - FileStore's name, on Windows we use the attribute volume:vsn instead
    since  the name is not necessarily unique.
  - separated by '|'
  e.g.
    "AdoptOpenJDK|1.8.0_212-b03|/dev/disk1s1"
  The same prefix is used as for filesystem timestamp resolution, so
  both values are stored in the same config section
- The config key for minmal racy threshold is "minRacyThreshold" as a
  time value, supported time units are those supported by
  DefaultTypedConfigGetter#getTimeUnit
- measure for 3 seconds to limit runtime which depends on hardware, OS
  and Java version being used

If the minimal racy threshold is configured for a given FileStore the
configured value is used instead of measuring it.

When the minimal racy threshold was measured it is persisted in the user
global git configuration.

Rename FileStoreAttributeCache to FileStoreAttributes since this class
is now declared public in order to enable exposing all attributes in one
object.

Example:

[filesystem "AdoptOpenJDK|11.0.3|/dev/disk1s1"]
	timestampResolution = 7000 nanoseconds
	minRacyThreshold = 3440 microseconds

Change-Id: I22195e488453aae8d011b0a8e3276fe3d99deaea
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Also-By: Marc Strapetz <marc.strapetz@syntevo.com>
2019-08-06 14:54:39 +02:00
Matthias Sohn 5911521ba6 Measure minimum racy interval to auto-configure FileSnapshot
By running FileSnapshotTest#detectFileModified we found that the sum of
measured filesystem timestamp resolution and measured clock resolution
may yield a too small interval after a file has been modified which we
need to consider racily clean. In our tests we didn't find this behavior
on all systems we tested on, e.g. on MacOS using APFS and Java 8 and 11
this effect was not observed.

On Linux (SLES 15, kernel 4.12.14-150.22-default) we collected the
following test results using Java 8 and 11:

In 23-98% of 10000 test runs (depending on filesystem type and Java
version) the test failed, which means the effective interval which needs
to be considered racily clean after a file was modified is larger than
the measured file timestamp resolution.

"delta" is the observed interval after a file has been modified but
FileSnapshot did not yet detect the modification:

"resolution" is the measured sum of file timestamp resolution and clock
resolution seen in Java.

Java version    filesystem  failures resolution  min delta   max delta
1.8.0_212-b04   btrfs	    98.6%       1 ms        3.6 ms      6.6 ms
1.8.0_212-b04   ext4        82.6%       3 ms        1.1 ms      4.1 ms
1.8.0_212-b04   xfs         23.8%       4 ms        3.7 ms      3.9 ms
1.8.0_212-b04   zfs         23.1%       3 ms        4.8 ms      5.0 ms
11.0.3+7        btrfs       98.1%       3 us        0.7 ms      4.7 ms
11.0.3+7        ext4        98.1%       6 us        0.7 ms      4.7 ms
11.0.3+7        xfs         98.5%       7 us        0.1 ms      8.0 ms
11.0.3+7        zfs         98.4%       7 us        0.7 ms      5.2 ms

Mac OS
1.8.0_212       APFS        0%          1 s
11.0.3+7        APFS        0%          6 us

The observed delta is not distributed according to a normal gaussian
distribution but rather random in the observed range between "min delta"
and "max delta".

Run this test after measuring file timestamp resolution in
FS.FileAttributeCache to auto-configure JGit since it's unclear what
mechanism is causing this effect.

In FileSnapshot#isRacyClean use the maximum of the measured timestamp
resolution and the measured "delta" as explained above to decide if a
given FileSnapshot is to be considered racily clean. Add a 30% safety
margin to ensure we are on the safe side.

Change-Id: I1c8bb59f6486f174b7bbdc63072777ddbe06694d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-08-06 14:54:35 +02:00
Matthias Sohn d17efe880d Fix FileAttributeCache.toString()
We should not list the complete cache but only show the cache entry at
hand.

Change-Id: I22be2a4dcbf0145155e23f2389bfcf5662cf23a6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
2019-07-26 15:53:29 +02:00