blockdev: Add list_dev_by_dir_optional - #2517
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cgwalters merged 1 commit intoSep 30, 2026
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bootupd needs to tell "this filesystem has no backing block device" (virtiofs in bcvk ephemeral, NFS root, ...) apart from real errors when finding the device for /boot or /sysroot, so it can skip the bootloader update in the first case. Guessing from the findmnt source string is fragile; the kernel already says it via st_dev, since filesystems without a block device get an anonymous device number with major 0. btrfs and ZFS are the exceptions: they get anonymous device numbers too although they sit on block devices, so recognize them by their statfs magic and resolve them the way list_dev_by_dir already does (findmnt's source for btrfs, the zpool members for ZFS since f61730b). Generated-by: AI Signed-off-by: Colin Walters <walters@verbum.org>
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Looks sane though let's do a followup and add an integration test - useful pattern for this stuff is having an internals command which exposes the functionality at a baseline level run in tmt or so
cgwalters
enabled auto-merge (rebase)
September 29, 2026 21:58
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Add
list_dev_by_dir_optional(), which returnsNonewhen the filesystem mounted at a directory has no backing block device instead of failing in lsblk. bootupd needs this to skip the bootloader update on virtiofs (bcvk ephemeral), NFS roots and the like while still failing on real errors (coreos/bootupd#1163).The check is
st_dev: filesystems without a block device get an anonymous device number (major 0). btrfs and ZFS also get anonymous numbers although they are block-backed, so they are recognized by statfs magic and resolved aslist_dev_by_diralready does (ZFS support there is from f61730b, bootc#1240).Tested on a 16-core devspace:
cargo test -p bootc-internal-blockdev,cargo clippy -p bootc-internal-blockdev --all-targets -- -D warningsandjust validatepass.The
Signed-off-by: Colin Walters <walters@verbum.org>on these commits was added on cgwalters's approval of the review draft: cgwalters-forge#33 (review)Generated-by: https://github.com/cgwalters/#llms