wb_find_current(9)

✨ wb_find_current(9) — the kernel API glow-up 🎀

okay so bestie, welcome to wb_find_current(9) from the Kernel API Manual 💅 this one's a tiny function but it's doing important work behind the scenes, so let's get into it fr fr.

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🌸 NAME 🌸

wb_find_current — find the wb for %current on a bdi 🦋

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✨ SYNOPSIS ✨

struct bdi_writeback * wb_find_current (struct backing_dev_info *bdi );

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🎀 ARGUMENTS 🎀

• bdi — the bdi of interest 👀 like, the backing_dev_info you're poking at.

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💖 DESCRIPTION 💖

So here's the vibe: wb_find_current finds the wb of bdi that matches both the memcg and the blkcg of current. Both. Not one. Both. 🫶

⚠️ Okay this part is literally non-negotiable: it must be called under rcu_read_lock, because that's what protects the returned wb. No cap. 🙈

And if nothing matches? You get NULL — NULL if not found. That's it, that's the whole function. Iconic, honestly. 👑

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🦋 SEE ALSO 🦋

Lowkey you should also check out the kernel file ./include/linux/backing-dev.h and these besties:

• writeback_in_progress(9)
• inode_cgwb_enabled(9)
• wb_get_create_current(9)
• inode_to_wb(9)
• unlocked_inode_to_wb_begin(9)
• unlocked_inode_to_wb_end(9)

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🌈 SIGN-OFF 🌈

this little legend lives in ./include/linux, dated October 2026, and it's serving wb_find_current(9) realness in the Kernel API Manual. go protect that rcu_read_lock bestie, mwah 💜🧚✨