rbd: Use assume_storage_prezeroed when formatting #4996
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Instead of passing lazy_itable_init=1 and lazy_journal_init=1 to mkfs.ext4, pass assume_storage_prezeroed=1 which is stronger and allows the filesystem to skip inode table zeroing completely instead of simply doing it lazily. Closes: ceph#4948 Signed-off-by: Niraj Yadav <niryadav@redhat.com>
| @@ -101,7 +101,7 @@ var ( | |||
| xfsHasReflink = xfsReflinkUnset | |||
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| mkfsDefaultArgs = map[string][]string{ | |||
| "ext4": {"-m0", "-Enodiscard,lazy_itable_init=1,lazy_journal_init=1"}, | |||
| "ext4": {"-m0", "-Enodiscard,assume_storage_prezeroed=1"}, | |||
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make sure that you only do this when mkfs.ext4 supports the option, you'll need to add some form of detection, ideally with something like sync.Once.
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assume_storage_prezeroedoption became available in e2fsprogs 1.47.0 last year, so it should probably be "discovered" similar toxfsSupportsReflink().
My suggestion to do it similar to xfsSupportsReflink() isn't viable because mkfs.ext4 doesn't include extended options in its help output, but trying with assume_storage_prezeroed=1 and falling back to lazy_itable_init=1,lazy_journal_init=1 upon parsing out Bad option(s) specified: assume_storage_prezeroed error should work.
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I and Madhu had a discussion on this. Since this flag is part of e2fsprogs >= 1.47 and we have control over which version of it we bundle in the container, do we really need this check?
Sidenote: Detection is possible by parsing the semver of e2fsprogs. It is standard flag so it must be there?
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The check for the version isn't always reliable in the face of downstream backports.
Describe what this PR does
Instead of passing
lazy_itable_init=1andlazy_journal_init=1tomkfs.ext4,pass
assume_storage_prezeroed=1which is stronger and allows the filesystemto skip inode table zeroing completely instead of simply doing it lazily.
Closes: #4948