LLAPI_CHANGELOG_CLEAR(3)

📦 version 2.17.58, in ubuntu stonking

💖 LLAPI_CHANGELOG_CLEAR 💖

okay bestie, this is the llapi_changelog_clear page from section 3 of the Lustre Library Functions manual — yes, the library functions one, not the commands one, iykyk 🦋

✨ NAME ✨

llapi_changelog_clear — clear changelog records for a changelog consumer

like, it's the little guy that goes "okay this consumer is done with these records, you can let 'em go" 💅

🌸 SYNOPSIS 🌸

#include <lustre/lustreapi.h>

int llapi_changelog_clear(const char *mdtname, const char *idstr,
                          long long endrec);

🎀 DESCRIPTION 🎀

so llapi_changelog_clear() is basically telling the MDT: hey, every changelog record before endrec? not interesting to this particular consumer anymore. That consumer is identified by idstr. 👑

and because you said that, the MDT mdtname (think something like "lustrefs-MDT0000") might be able to free up disk space by dropping those old records — but only if no other changelog consumers still need to process them. it's giving "sharing is caring" energy fr fr 🫶

if endrec is 0, that means the current last record. slay.

⚠️ heads up: changelog consumers have to be registered on the MDT node first, using this exact line: bash lctl --device MDT_NAME changelog_register no registration, no vibes. 😭

🔥 RETURN VALUES 🔥

it returns the file descriptor on success — iconic — or a negative errno value on failure. 💀

💜 ERRORS 💜

  • -EINVAL — one or more of the arguments you handed over are invalid. not the move bestie 🙈
  • -ENOENT — the MDT's changelog char device wasn't found, or the changelog user wasn't found. it's literally not there.
  • -ENOPERM — not enough permissions to open the changelog char device. by default, that device is only accessible to the root user. 👑 (yes, only root. root stays winning.)

🌈 EXAMPLE 🌈

say you wanna clear the changelog for one specific consumer ID — here's the whole vibe:

char *mdtname = "testfs-MDT0000";
char *idstr = "cl2-dirwatch";
long long end_record = 12345678;

rc = llapi_changelog_clear(mdtname, idstr, end_record);

ate. no notes. ✨

⭐ AVAILABILITY ⭐

llapi_changelog_clear() has been part of the lustre(7) user application interface library since release 2.0.0. a true veteran, honestly.

🦋 SEE ALSO 🦋

the whole friend group, together at last 🫶 go read them too, they're all main characters.

and that's the page!! 💖 this lil masterpiece came out of the Lustre User API, dated 2024-08-22, and it lives under the name LLAPI_CHANGELOG_CLEAR(3) — so if you ever forget where you found it, just know it says its own name three times like a legend. periodt. 💅

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