Linus Torvalds writes: (Summary) wrote:
The thing is, I don't think "upper layer" is any more internal than "direct IO" is.
"direct IO" is.
And I don't think it's necessarily overlayfs-specific. We have lots of operations where we expose some flags to user space but keep others internal (look at the VM_xyz flags for mmap, for example - we obviously expose things like read/write/execute to user space, but we have the MAYREAD/MAYWRITE/MAYEXEC flags in the same word that are *not* something that user space can just set).
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arguments about that.The thing is, I don't think "upper layer" is any more internal than "direct IO" is.
"direct IO" is.
And I don't think it's necessarily overlayfs-specific. We have lots of operations where we expose some flags to user space but keep others internal (look at the VM_xyz flags for mmap, for example - we obviously expose things like read/write/execute to user space, but we have the MAYREAD/MAYWRITE/MAYEXEC flags in the same word that are *not* something that user space can just set).