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On 04/26 09:58, Rich Freeman wrote: |
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> On Sun, Apr 26, 2020 at 9:43 PM <tuxic@××××××.de> wrote: |
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> > |
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> > To implement a dry run with a printf() is new to me... ;) |
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> > |
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> |
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> That is all they fstrim authors could do, since there is no dry-run |
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> option for the actual ioctl, and fstrim itself has no idea how the |
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> filesystem will implement it (short of re-implementing numerous |
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> filesystems in the program and running it on unmounted devices). It |
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> seems like an fstrim dry-run is only minimally functional, though I |
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> guess it will test if you made any gross errors in syntax and so on. |
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> I don't see any reason why they couldn't have a dry-run option for the |
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> ioctl, but it would have to be implemented in the various filesystems. |
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> Really it seems like ioctl in general in the kernel isn't |
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> super-well-documented. It isn't like the system call interface. That |
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> is, unless I just missed some ioctl document floating around. The |
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> actual list of ioctls is in the kernel includes, but this does not |
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> define the syntax of the 3rd parameter of the ioctl system call which |
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> is function-specific. The structure used by the FITRIM ioctl is in the |
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> includes, but not with any kind of documentation or even a |
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> cross-reference to associate the structure with the ioctl itself. |
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> |
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> -- |
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> Rich |
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> |
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Hi Rich, |
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thanks for the explanations again. |
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But I think it is better not to implement a feature at all as via |
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printf. |
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For a dry run I had expected, that some checks had been implemented, |
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whether a non-dry run would be successfull. |
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For example: |
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When submitting |
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fstrim -n / |
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as normal user I get: |
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/: 0 B (dry run) trimmed |
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Doing the same without dry run set I get: |
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fstrim: /: FITRIM ioctl failed: Operation not permitted |
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When doing a |
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fstrim -n /home/user |
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as normal user, I get the same behaviour as above -- |
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despite that /home/user is on a harddisk with no |
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fstrim functionality at all. |
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If fstrim cannot implement the above correctlu, it would |
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be better not to implement it all...I think. |
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Cheers! |
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Meino |
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