Do not stop directory listing when ACL is blocking access (local external storage)

Same as
#26658
but not for "external storage | smb" but "external storage | local".

Details:
#26658 (comment)

Hi! So im on the 21.0.3 docker version, this fix was backported to - still having the issue with local-mounted external folders:
Running: docker exec --user www-data nc_dd_app_1 php occ files:scan --path="/Dominik/files/nas_Setups/Tools"
still getting a Permission denied exception:

Exception during scan: opendir(/mnt/nas_Setups/Tools/@eaDir): failed to open dir: Permission denied
#0 [internal function]: OCA\Files\Command\Scan->exceptionErrorHandler(2, 'opendir(/mnt/na...', '/var/www/html/l...', 135, Array)
#1 /var/www/html/lib/private/Files/Storage/Local.php(135): opendir('/mnt/nas_Setups...')
#2 /var/www/html/lib/private/Files/Storage/Common.php(878): OC\Files\Storage\Local->opendir('Tools/@eaDir')
#3 /var/www/html/lib/private/Files/Storage/Wrapper/PermissionsMask.php(158): OC\Files\Storage\Common->getDirectoryContent('Tools/@eaDir')
#4 [internal function]: OC\Files\Storage\Wrapper\PermissionsMask->getDirectoryContent('Tools/@eaDir')
#5 /var/www/html/lib/private/Files/Cache/Scanner.php(409): iterator_to_array(Object(Generator))
#6 /var/www/html/lib/private/Files/Cache/Scanner.php(389): OC\Files\Cache\Scanner->handleChildren('Tools/@eaDir', true, 3, 1046216, true, 0)
#7 /var/www/html/lib/private/Files/Cache/Scanner.php(392): OC\Files\Cache\Scanner->scanChildren('Tools/@eaDir', true, 3, 1046216, true)
#8 /var/www/html/lib/private/Files/Cache/Scanner.php(341): OC\Files\Cache\Scanner->scanChildren('Tools', true, 3, 864151, true)
#9 /var/www/html/lib/private/Files/Utils/Scanner.php(260): OC\Files\Cache\Scanner->scan('Tools', true, 3)
#10 /var/www/html/apps/files/lib/Command/Scan.php(158): OC\Files\Utils\Scanner->scan('/Dominik/files/...', true, NULL)
#11 /var/www/html/apps/files/lib/Command/Scan.php(214): OCA\Files\Command\Scan->scanFiles('Dominik', '/Dominik/files/...', Object(Symfony\Component\Console\Output\ConsoleOutput), false, true, false)
#12 /var/www/html/3rdparty/symfony/console/Command/Command.php(255): OCA\Files\Command\Scan->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#13 /var/www/html/core/Command/Base.php(169): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#14 /var/www/html/3rdparty/symfony/console/Application.php(1009): OC\Core\Command\Base->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#15 /var/www/html/3rdparty/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand(Object(OCA\Files\Command\Scan), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#16 /var/www/html/3rdparty/symfony/console/Application.php(149): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#17 /var/www/html/lib/private/Console/Application.php(215): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#18 /var/www/html/console.php(100): OC\Console\Application->run()
#19 /var/www/html/occ(11): require_once('/var/www/html/c...')
#20 {main}

ACL for the folder is user:nextcloud_docker:deny:rwxpdDaARWcCo:fd-- (level:0)

[szaimen]

I suppose this is still happening on NC21.0.4?

This issue has been automatically marked as stale because it has not had recent activity and seems to be missing some essential information. It will be closed if no further activity occurs. Thank you for your contributions.

[alanswanson]

Having the same problem with a local external storage provided read only to all users.

Noticed that it NC stopped updating any file additions/removals to the local external storage shortly after updating from 21.0.4 to 21.0.5 but soon after had also changed the local external storage from an ext4 filesystem mountpoint to an overlayfs lowerdirs only mountpoint (a merged JBOD with the original ext4 filesystem).

Running occ files:scan shows it flaking at a permission denied with the "lost+found" directory. Since "lost+found" directories permission have always been root 700 not sure why it started failing when it was scanning fine before. The overlayfs doesn't cause any user visible changes and I can't see anything specific in 21.0.5. Very odd...

As a workaround I've added "lost+found" to the isIgnoredDir list in lib/private/Files/Filesystem.php file but for external storage all permission failures should be a warning and carry on, not an exception and stop.

$ php occ -vvv files:scan --all
Starting scan for user 1 out of 5 (admin)
        Folder  /admin/
        Folder  /admin/cache
        Folder  /admin/files
        Folder  /admin/files/Media/
        Folder  /admin/files/Media/lost+found/
Exception during scan: opendir(/usr/local/media/lost+found): failed to open dir: Permission denied
#0 [internal function]: OCA\Files\Command\Scan->exceptionErrorHandler()
#1 /var/www/localhost/htdocs/cloud/lib/private/Files/Storage/Local.php(135): opendir()
#2 /var/www/localhost/htdocs/cloud/lib/private/Files/Storage/Common.php(878): OC\Files\Storage\Local->opendir()
#3 /var/www/localhost/htdocs/cloud/lib/private/Files/Storage/Wrapper/PermissionsMask.php(158): OC\Files\Storage\Common->getDirectoryContent()
#4 /var/www/localhost/htdocs/cloud/lib/private/Files/Storage/Wrapper/PermissionsMask.php(158): OC\Files\Storage\Wrapper\PermissionsMask->getDirectoryContent()
#5 [internal function]: OC\Files\Storage\Wrapper\PermissionsMask->getDirectoryContent()
#6 /var/www/localhost/htdocs/cloud/lib/private/Files/Cache/Scanner.php(409): iterator_to_array()
#7 /var/www/localhost/htdocs/cloud/lib/private/Files/Cache/Scanner.php(389): OC\Files\Cache\Scanner->handleChildren()
#8 /var/www/localhost/htdocs/cloud/lib/private/Files/Cache/Scanner.php(392): OC\Files\Cache\Scanner->scanChildren()
#9 /var/www/localhost/htdocs/cloud/lib/private/Files/Cache/Scanner.php(341): OC\Files\Cache\Scanner->scanChildren()
#10 /var/www/localhost/htdocs/cloud/lib/private/Files/Utils/Scanner.php(260): OC\Files\Cache\Scanner->scan()
#11 /var/www/localhost/htdocs/cloud/apps/files/lib/Command/Scan.php(158): OC\Files\Utils\Scanner->scan()
#12 /var/www/localhost/htdocs/cloud/apps/files/lib/Command/Scan.php(214): OCA\Files\Command\Scan->scanFiles()
#13 /var/www/localhost/htdocs/cloud/3rdparty/symfony/console/Command/Command.php(255): OCA\Files\Command\Scan->execute()
#14 /var/www/localhost/htdocs/cloud/core/Command/Base.php(169): Symfony\Component\Console\Command\Command->run()
#15 /var/www/localhost/htdocs/cloud/3rdparty/symfony/console/Application.php(1009): OC\Core\Command\Base->run()
#16 /var/www/localhost/htdocs/cloud/3rdparty/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand()
#17 /var/www/localhost/htdocs/cloud/3rdparty/symfony/console/Application.php(149): Symfony\Component\Console\Application->doRun()
#18 /var/www/localhost/htdocs/cloud/lib/private/Console/Application.php(215): Symfony\Component\Console\Application->run()
#19 /var/www/localhost/htdocs/cloud/console.php(100): OC\Console\Application->run()
#20 /var/www/localhost/htdocs/cloud/occ(11): require_once('/var/www/localh...')
#21 {main}