.TH LLAPI_CHANGELOG_CLEAR 3 2024-08-22 "Lustre User API" "Lustre Library Functions"
.SH NAME
llapi_changelog_clear \- Clear changelog records for a changelog consumer
.SH SYNOPSIS
.nf
.B #include <lustre/lustreapi.h>
.PP
.BI "int llapi_changelog_clear(const char *" mdtname ", const char *" idstr ",
.BI "                          long long " endrec ");"
.fi
.SH DESCRIPTION
The function
.B llapi_changelog_clear()
indicates that changelog records previous to
.I endrec
are no longer of interest to a particular consumer
.I idstr
, potentially allowing the MDT
.I mdtname
(e.g: "lustrefs-MDT0000") to free up disk space by freeing old records
if no other changelog consumers still need to process them.
.PP
An
.I endrec
of 0 indicates the current last record.
.PP
Changelog consumers must be registered on the
MDT node using:
.br
.BI "lctl --device " MDT_NAME " changelog_register"
.SH RETURN VALUES
Return the file descriptor on success or a negative errno value on failure.
.SH ERRORS
.TP 15
.SM -EINVAL
One or more invalid arguments are given.
.TP
.SM -ENOENT
MDT's changelog char device or changelog user not found.
.TP
.SM -ENOPERM
Not enough permissions to open the changelog char device.
By default, the device is only accessible to the root user.
.SH EXAMPLE
To clear the changelog for a specific consumer ID:
.EX
        char *mdtname = "testfs-MDT0000";
        char *idstr = "cl2-dirwatch";
        long long end_record = 12345678;
\&
        rc = llapi_changelog_clear(mdtname, idstr, end_record);
.EE
.SH AVAILABILITY
.B llapi_changelog_clear()
is part of the
.BR lustre (7)
user application interface library since release 2.0.0.
\" Added in commit 1.6.0-3165-g8901d15087b2
.SH SEE ALSO
.BR lfs-changelog_clear (1),
.BR llapi_changelog_get_fd (3),
.BR llapi_changelog_in_buf (3),
.BR llapi_changelog_recv (3),
.BR llapi_changelog_start (3),
.BR llapi_changelog_start_user (3),
.BR lustreapi (7),
.BR lctl-changelog_register (8)