Fix zdb crash with 4K-only devices #4821
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| * Since userland probably doesn't need optimized buffer caches, | ||
| * we just force 4K alignment on everything. | ||
| */ | ||
| align = PAGESIZE; |
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Maybe this should be 4096 explicitly, instead of PAGESIZE.
XFS requires logical sector size of the target for alignment link
But how this translates to kernel slabs, is alignment required there as well?
Currently, zio_buf slabs are setup like this:
size: 512 align: 512
size: 1024 align: 512
size: 1536 align: 512
size: 2048 align: 512
size: 2560 align: 512
size: 3072 align: 512
size: 3584 align: 512
size: 4096 align: 1024 <==
size: 5120 align: 1024
size: 6144 align: 1024
size: 7168 align: 1024
size: 8192 align: 2048
size: 10240 align: 2048
size: 12288 align: 2048
size: 14336 align: 2048
size: 16384 align: 4096
size: 20480 align: 4096
.... align: 4096
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Maybe this should be 4096 explicitly, instead of PAGESIZE.
That's not a bad idea, assuming PAGESIZE in 4096 is a bit x86_64 centric.
There is a similar restriction for the kernel slabs but the per-disk ashift is used for the alignment. The biovec which is constructed for the IO maps the appropriate portions of the pages which make up the slab buffer in to the bios.
Here's the problem - on 4K native devices in userland on Linux using O_DIRECT, buffers must be 4K aligned or I/O will fail with EINVAL, causing zdb (and others) to coredump. Since userland probably doesn't need optimized buffer caches, we just force 4K alignment on everything. Issue openzfs#4479
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Merged as: fcf64f4 Fix zdb crash with 4K-only devices |
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Here's the problem - on 4K native devices in userland on
Linux using O_DIRECT, buffers must be 4K aligned or I/O
will fail with EINVAL, causing zdb (and others) to coredump.
Since userland probably doesn't need optimized buffer caches,
we just force 4K alignment on everything.
Issue #4479