drbd_md_read(9)

💖 drbd_md_read(9) 💖

okay bestie, welcome to the Kernel API Manual ✨ — yes, the kernel API manual, we're in that part of the source tree today, and honestly? it's giving legendary.

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🌸 NAME 🌸

drbd_md_read — reads in the meta data super block 🎀

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⭐ SYNOPSIS ⭐

int drbd_md_read (struct drbd_device *device , struct drbd_backing_dev
*bdev );

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🦋 ARGUMENTS 🦋

• device — the DRBD device, your main character fr fr 👑
• bdev — the device that the meta data should be read in from 🍓

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✨ DESCRIPTION ✨

so here's the vibe: you get NO_ERROR back when everything slays 💅 and you get an enum drbd_ret_code when something goes wrong 😭 — no cap, that's the whole return situation.

the way that this gets called is so specific: it's called exactly once during drbd_adm_attach, and it happens while the device is still being D_DISKLESS, even before bdev is assigned to device->ldev. like, it's early early. pre-assignment early. 🌈

highkey important, bestie — exactly once and before the assignment are not decorative details, they're the whole point of this little guy's existence 🙈

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🔥 SEE ALSO 🔥

kernel file ./drivers/block/drbd/drbd_main.c, plus the whole squad 🫶

• tl_release(9)
• _tl_restart(9)
• tl_clear(9)
• tl_abort_disk_io(9)
• drbd_thread_current_set_cpu(9)
• drbd_send_current_state(9)
• drbd_send_state(9)
• _drbd_send_ack(9)
• drbd_send_ack(9)
• drbd_md_sync(9)
• drbd_md_mark_dirty(9)
• drbd_uuid_new_current(9)
• drbd_bmio_set_n_write(9)
• drbd_bmio_clear_n_write(9)
• drbd_queue_bitmap_io(9)
• drbd_bitmap_io(9)
• drbd_wait_misc(9)

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and that's the page, bestie 💜 sign-off time: this one lives in ./drivers/block/drbd, dated October 2026, and it's filed under drbd_md_read(9). iconic behavior from start to finish, ngl 🧚‍♀️✨