fscache_acquire_volume(9)

📦 version 7.3.1, in nixpkgs unstable

🦋 fscache_acquire_volume(9) — the "hey bestie, let's get this volume cached" moment

Okay so like, this page lives in the Kernel API Manual and it's all about fscache_acquire_volume — the function that's literally manifesting caching services for a volume. No cap, it's giving "register me for the vibe treatment." ✨

🌸 SYNOPSIS

struct fscache_volume * fscache_acquire_volume (const char *volume_key ,
       const char *cache_name , const void *coherency_data , size_t
       coherency_len );

💅 ARGUMENTS (the whole cast, not me forgetting anyone)

  • volume_key — an identification string for the volume. Like its little name tag at the cache party 🎀
  • cache_name — the name of the cache to use, or NULL for the default one. Yes bestie, NULL is a whole valid vibe here.
  • coherency_data — a piece of arbitrary coherency data to check, or NULL if you're not about that. 🙈
  • coherency_len — the size of the coherency data. Gotta know how much data we're data-ing, fr fr.

🔥 DESCRIPTION

So basically: you call this to register a volume as desiring caching services if they're available — key phrase, if they're available, don't come for me. The caller must provide an identifier for the volume, and may also indicate which cache it should live in. Slay, optional.

Now here's the part that matters: if a preexisting volume entry is found in the cache, the coherency data must match — otherwise the entry gets invalidated. Periodt. No matching coherency data, no entry. It's giving strict but fair. 💀

On success you get a cookie pointer back. If the memory gods say no, you get -ENOMEM. And if a cache volume of that name is already acquired, you get -EBUSY — like sorry babe, taken. 👑

Also important and lowkey iconic: NULL is a valid cookie pointer and can be returned if caching is refused. So don't panic if you see NULL, it's not an error, it's just the cache saying "not today." 🫶

👑 SEE ALSO

Kernel file ./include/linux/fscache.h plus the whole friend group:

Okay that's the whole page, bestie. It lives at ./include/linux, dated October 2026, and it's the fscache_acquire_volume(9) manual page. Go forth and acquire those volumes. You're gonna slay. 💖✨🌈

📦 where this page comes from