fix: accept blocksize=4096 in fat32.Read for 4k native block devices#320
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deitch merged 1 commit intodiskfs:masterfrom Dec 23, 2025
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When go-diskfs opens a 4k native block device, it detects the logical block size as 4096 from the OS and passes this to fat32.Read(). However, the validation was rejecting any blocksize other than 0 or 512, causing 'unknown filesystem' errors. This is a follow-up to PR diskfs#316 which added support for reading FAT32 filesystems with bytesPerSector=4096 from the BPB, but didn't update the blocksize validation. The blocksize parameter is only used for validation; the actual bytesPerSector is always read from the BPB. Fixes reading VFAT filesystems on 4k native disks when opened as block devices (e.g., /dev/vda1). Also fix the write code for 4k disks. Signed-off-by: Noel Georgi <git@frezbo.dev>
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To see the 4k failure we need an actual loop device or block device. |
deitch
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Dec 23, 2025
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Looks good, thank you. |
jfroy
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Apr 21, 2026
This patch allows creating FAT32 filesystems with 4K block size. This is intended to create UEFI System Partitions (ESPs) on NVME namespaces with a 4Kn format. This is a follow-up to PR diskfs#320 which added support for reading FAT32 filesystems with 4K block size. Signed-off-by: Jean-Francois Roy <jf@devklog.net> Assisted-by: Claude:claude-opus-4-7
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When go-diskfs opens a 4k native block device, it detects the logical block size as 4096 from the OS and passes this to fat32.Read(). However, the validation was rejecting any blocksize other than 0 or 512, causing 'unknown filesystem' errors.
This is a follow-up to PR #316 which added support for reading FAT32 filesystems with bytesPerSector=4096 from the BPB, but didn't update the blocksize validation. The blocksize parameter is only used for validation; the actual bytesPerSector is always read from the BPB.
Fixes reading VFAT filesystems on 4k native disks when opened as block devices (e.g., /dev/vda1).
Also fix the write code for 4k disks.