fscache_begi...ad_operation(9)

📦 version 7.3.1, in nixpkgs unstable

✨ fscache_begin_read_operation(9) ✨

okay so bestie, buckle up 💖 we're in the Kernel API Manual today and this one is genuinely a little gem. it's from ./include/linux/fscache.h and it's all about kicking off a read operation for the netfs library. no cap, it's short but it matters 🎀

🌸 SYNOPSIS 🌸

int fscache_begin_read_operation (struct netfs_cache_resources *cres ,
struct fscache_cookie *cookie );

like, that's the whole signature. two args, one int, very demure, very mindful 💅

🦋 ARGUMENTS 🦋

  • cres — the cache resources for the read that's being performed. this is where the operation state gets attached, so it's kind of the main character here 👑
  • cookie — the cookie representing the cache object. yes, a cookie. in the kernel. we love a whimsical naming moment 🍪

🌈 DESCRIPTION 🌈

so what does it actually do? it begins a read operation on behalf of the netfs helper library. cres tells it which cache resources the operation state should be attached to, and cookie points at the cache object that's gonna get accessed. simple, iconic, slay ✨

and here's the lowkey important bit: cres->inval_counter gets set from cookie->inval_counter so the two can be compared at the end of the operation. why? because that's how the caller detects if an invalidation happened mid-operation 🫶 like a lil vibe check for your cache state, iykyk.

💜 RETURN 💜

  • 0 — success 🎉 everything's fine, we ate
  • -ENOBUFS — no caching available 😭 there's just nothing to work with
  • other error code from the cache, such as -ENOMEM — the cache said no and gave you its own reason 💀

⭐ SEE ALSO ⭐

the kernel file ./include/linux/fscache.h, plus this whole squad of related friends — go read them, fr fr:

bestie reminder: fscache_begin_read_operation is the begin half. don't forget its partner fscache_end_operation(9) or you'll leave things dangling and that's not the vibe 🙈

and that's a wrap, gorgeous 🌸 this page lives in ./include/linux and it's dated October 2026 — mwah, go forth and read your cache responsibly 💖🧚‍♀️

📦 where this page comes from