dax_iomap_fault(9)

📦 version 7.3.1, in nixpkgs unstable

okay bestie, welcome to the Kernel API Manual corner for dax_iomap_fault(9) — yes, this whole page is about one helper and it's lowkey iconic 💅

🌸 NAME 🌸

dax_iomap_fault — handle a page fault on a DAX file. That's the whole vibe: DAX file, page fault, handle it ✨

✨ SYNOPSIS ✨

here's the signature, bestie — copy it exactly, no freestyling:

vm_fault_t dax_iomap_fault (struct vm_fault *vmf , unsigned int order ,
unsigned long *pfnp , int *iomap_errp , const struct iomap_ops *ops );

💖 ARGUMENTS 💖

okay so every parameter, and what it's giving:

  • vmf — the description of the fault. literally the fault's whole story 🫶
  • order — order of the page to fault in. yes ma'am, the page order 🔥
  • pfnp — PFN to insert for synchronous faults if fsync is required. so that's the synchronous-faults-with-fsync situation, no cap 💅
  • iomap_errp — storage for detailed error code in case of error. so when things go 💀, the detailed error code can live here
  • ops — Iomap ops passed from the file system. handed over by the fs, periodt 🎀

🦋 DESCRIPTION 🦋

When a page fault occurs, filesystems may call this helper in their fault handler for DAX files. that's the main character moment right there 🌟

dax_iomap_fault assumes the caller has done all the necessary locking for page fault to proceed successfully — so like, do your locking first, bestie, because this helper is assuming it's already handled 🙈

🎀 SEE ALSO 🎀

Kernel file ./fs/dax.c is the place, and these are the linked faves:

mwah 💋 this page came from ./fs, dated October 2026, and it's all about dax_iomap_fault(9) — source/version and date, all accounted for 🫶✨

📦 where this page comes from