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Can't run Flutter on NFS (flock reports "Bad file descriptor") #6549

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Can't run Flutter on NFS (flock reports "Bad file descriptor")#6549
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Hixie
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toolAffects the "flutter" command-line tool. See also t: labels.waiting for PR to land (fixed)A fix is in flight
Milestone
3: Current Milestone

Description

@droundy
droundy
opened on Oct 27, 2016

Steps to Reproduce

I expect you may have difficulty reproducing this, but I run into the following error when running flutter:

$ flutter
flock: 3: Bad file descriptor

The error happens at line 35 of the flutter shell script, which tries to take a lock using the flock utility. This is on a debian stable computer, and I have no experience using flock with bash, and haven't been able to debug it. I can make flutter work fine by changing the preceding line such that the if statement fails and a lock is not taken.

I presume file descriptor 3 is supposed to be created by line 50, which reads:

) 3< $PROG_NAME

but don't care to learn enough bash to figure out why it is not working, particularly as I have a workaround. But it does seem worth fixing, to make flutter work for folks who aren't comfortable editing a bash script.

Logs

Can't do this since flutter fails. Unless I disable the lock, in which case it works fine.

Flutter Doctor

Again, not relevant.

Activity

  1. chinmaygarde
    added
    toolAffects the "flutter" command-line tool. See also t: labels.
    on Oct 27, 2016

  2. abarth commented on Oct 27, 2016

    @abarth
    abarth
    on Oct 27, 2016
    Contributor

    @Hixie

  3. Hixie commented on Oct 27, 2016

    @Hixie
    Hixie
    on Oct 27, 2016
    Contributor

    What version of bash?

  4. droundy commented on Oct 27, 2016

    @droundy
    droundy
    on Oct 27, 2016
    Author

    $ bash --version
    GNU bash, version 4.3.30(1)-release (x86_64-pc-linux-gnu)
    Copyright (C) 2013 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html

    This is free software; you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

  5. Hixie commented on Oct 27, 2016

    @Hixie
    Hixie
    on Oct 27, 2016
    Contributor

    Can you add the indicated line below to your flutter shell script in the indicated position and tell me everything that prints when you run flutter doctor?

    ...
(
  if hash flock 2>/dev/null; then
    stat "$PROG_NAME"                   # ADD THIS LINE
    flock 3 # ensures that we don't simultaneously update Dart in multiple parallel instances
    # some platforms (e.g. Mac) don't have flock or any reliable alternative
  fi
...

  6. droundy commented on Oct 27, 2016

    @droundy
    droundy
    on Oct 27, 2016
    Author

    $ bash --version
    GNU bash, version 4.3.30(1)-release (x86_64-pc-linux-gnu)
    Copyright (C) 2013 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html

    This is free software; you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

    On Wed, Oct 26, 2016 at 8:29 PM Ian Hickson [email protected]
    wrote:

    What version of bash?

    —
    You are receiving this because you authored the thread.
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    #6549 (comment),
    or mute the thread
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    .

  7. droundy commented on Oct 28, 2016

    @droundy
    droundy
    on Oct 28, 2016
    Author
    $ bin/flutter
  File: ‘/home/droundy/src/flutter/bin/flutter’
  Size: 2236        Blocks: 8          IO Block: 1048576 regular file
Device: 27h/39d Inode: 43385868    Links: 1
Access: (0755/-rwxr-xr-x)  Uid: ( 1137/ droundy)   Gid: (  100/   users)
Access: 2016-10-28 12:17:36.788721252 -0700
Modify: 2016-10-28 12:18:09.808504939 -0700
Change: 2016-10-28 12:18:09.808504939 -0700
 Birth: -
flock: 3: Bad file descriptor

  8. droundy commented on Oct 28, 2016

    @droundy
    droundy
    on Oct 28, 2016
    Author

    It just occurred to me that this is in an NFS-mounted directory, and I know NFS has some differences in locking. Flutter works fine in /tmp, which is tmpfs. So I guess maybe you can somehow identify that NFS is in use and avoid flock in that case?

  9. Hixie commented on Oct 28, 2016

    @Hixie
    Hixie
    on Oct 28, 2016
    Contributor

    I agree that NFS and locking don't do well, but I wouldn't have expected "Bad file descriptor"...

  10. Hixie
    added this to the milestone on Feb 27, 2017

  11. droundy commented on Oct 31, 2017

    @droundy
    droundy
    on Oct 31, 2017
    Author

    Any chance that a fix for this could go in, so I could use flutter in my home directory over nfs? My current fix is to edit bin/flutter to change 'if hash flock...' to have a misspelling in flock, so that it doesn't use flock, which fails on nfs. I'm not sure what a proper fix would be, not being an expert in the use of flock.

  12. Hixie commented on Dec 20, 2017

    @Hixie
    Hixie
    on Dec 20, 2017
    Contributor

    The problem seems to be that NFS doesn't support exclusive locking on a file descriptor opened in read-only mode, because it wants to write in order to lock the file.

  13. Hixie commented on Dec 20, 2017

    @Hixie
    Hixie
    on Dec 20, 2017
    Contributor

    We could just ignore errors from flock, I guess... if you replace the flock 3 line with flock 3 || true, does it work for you?

  14. Hixie
    changed the title [-]flock 3: Bad file descriptor[/-] [+]Can't run Flutter on NFS (flock reports "Bad file descriptor")[/+] on Dec 20, 2017
  15. Hixie
    self-assigned this
    on Dec 20, 2017

  16. Hixie commented on Jan 6, 2018

    @Hixie
    Hixie
    on Jan 6, 2018
    Contributor

    Possible workaround in #13955

  17. Hixie
    added
    waiting for PR to land (fixed)A fix is in flight
    on Jan 6, 2018
  18. Hixie
    closed this as completedon Jan 10, 2018

  19. Hixie commented on Jan 10, 2018

    @Hixie
    Hixie
    on Jan 10, 2018
    Contributor

    Please let me know if that didn't fix it.

  20. droundy commented on Jan 19, 2018

    @droundy
    droundy
    on Jan 19, 2018 via email
    Author

  21. Hixie commented on Jan 19, 2018

    @Hixie
    Hixie
    on Jan 19, 2018
    Contributor

    Awesome, thanks! Good luck with Flutter!

  22. rmacnak-google
    added a commit that references this issue on Oct 16, 2018

    Roll engine to aed6b8c.

    a34488d
  23. engine-flutter-autoroll
    added 2 commits that reference this issue on Oct 17, 2018

    Roll engine 08272ee..04c860f (19 commits)

    98f2252

    Roll engine 08272ee..04c860f (19 commits) (#23219)

    44c0080

  24. github-actions commented on Sep 4, 2021

    @github-actions
    github-actionsbot
    on Sep 4, 2021

    This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

  25. github-actions
    locked as resolved and limited conversation to collaborators on Sep 4, 2021
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