8293502: (fc) FileChannel::transfer methods fail to copy /proc files on Linux

[bplb]

Files in /proc advertise a size of zero for which direct and mapped transfers do not work. For this case, fall back to arbitrary channel transfer.

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Issue

• JDK-8293502: (fc) FileChannel::transfer methods fail to copy /proc files on Linux

Reviewers

• Alan Bateman (@AlanBateman - Reviewer)

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[mlbridge]

Webrevs

• 01: Full - Incremental (95901194)
• 00: Full (1b009421)

[AlanBateman]

This means an extra fstat per transferFrom but maybe you've measured it with small files and it's okay?

[bplb]

It's about 20% slower for sizes 32 and 4096 (disk block size), and about 13% slower for size 32768. Instead making the direct and trusted methods fail independently does not help.

[AlanBateman]

Thanks for the updates, 9590119 looks good.

[openjdk]

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8293502: (fc) FileChannel::transfer methods fail to copy /proc files on Linux

Reviewed-by: alanb

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At the time when this comment was updated there had been 53 new commits pushed to the master branch:

• f42caef: 8293550: Optionally add get-task-allow entitlement to macos binaries
• 5feca68: 8293840: RISC-V: Remove cbuf parameter from far_call/far_jump/trampoline_call
• 39cd163: 8293578: Duplicate ldc generated by javac
• 7765942: 8290367: Update default value and extend the scope of com.sun.jndi.ldap.object.trustSerialData system property
• 11e7d53: 8293819: sun/util/logging/PlatformLoggerTest.java failed with "RuntimeException: Retrieved backing PlatformLogger level null is not the expected CONFIG"
• 141d5f5: 8293767: AWT test TestSinhalaChar.java has old SCCS markings
• 3beca2d: 8291600: [vectorapi] vector cast op check is not always needed for vector mask cast
• 9a40b76: 8293842: IPv6-only systems throws UnsupportedOperationException for several socket/TCP options
• bb9aa4e: 8293813: ProblemList com/sun/jdi/JdbLastErrorTest.java on windows-x64 in Xcomp mode
• 4cec141: 8291509: Minor cleanup could be done in sun.security
• ... and 43 more: https://git.openjdk.org/jdk/compare/524af949370990df6f58a84ad2493eb1dcba2231...master

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[bplb]

/integrate

[openjdk]

Going to push as commit 6e23b43.
Since your change was applied there have been 80 commits pushed to the master branch:

• 1f9ff41: 8292297: Fix up loading of override java.security properties file
• 64b96e5: 8293811: Provide a reason for PassFailJFrame.forceFail
• f91762f: 8293965: Code signing warnings after JDK-8293550
• 8082c24: 8054572: [macosx] JComboBox paints the border incorrectly
• b920d29: 8271328: User is able to choose the color after disabling the color chooser.
• 5725a93: 8293879: Remove unnecessary castings in jdk.hotspot.agent
• ab7f58a: 6286501: JTabbedPane throws NPE from its stateChanged listener in particular case
• d41f69f: 8293849: PrintIdealPhase in compiler directives file is ignored when used with other compile commands
• 471e2f1: 8292088: C2: assert(is_OuterStripMinedLoop()) failed: invalid node class: IfTrue
• a93cf92: 8293920: G1: Add index based heap region iteration
• ... and 70 more: https://git.openjdk.org/jdk/compare/524af949370990df6f58a84ad2493eb1dcba2231...master

Your commit was automatically rebased without conflicts.

[openjdk]

@bplb Pushed as commit 6e23b43.

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