LLAPI\_CHANGELOG\_START(3) Lustre Library Functions LLAPI\_CHANGELOG\_START(3) # [NAME](#NAME) llapi\_changelog\_start, llapi\_changelog\_start\_user, llapi\_changelog\_set\_xflags, llapi\_changelog\_fini - Initialize and clean a read instance for MDT changelogs # [SYNOPSIS](#SYNOPSIS) ``` #include ``` ``` int llapi_changelog_start(void **priv, enum changelog_send_flag flags, const char *device, long long startrec); ``` ``` int llapi_changelog_start_user(void **priv, enum changelog_send_flag flags, const char *device, const char *username, __u64 mask, long long startrec); ``` ``` int llapi_changelog_set_xflags(void *priv, enum changelog_send_extra_flag extra_flags); ``` ``` int llapi_changelog_fini(void **priv); ``` # [DESCRIPTION](#DESCRIPTION) The function **llapi\_changelog\_start()** initializes a new instance *priv* to read MDT changelogs. It opens the changelog char device corresponding to the MDT's name given by *device* (e.g: "lustrefs-MDT0000"). A changelog starting point can be specified with *startrec* record number. **llapi\_changelog\_recv()** will get changelog records with numbers greater or equal than *startrec*. 0 value means that all records will be read. Some options can be passed to **llapi\_changelog\_start()** with *flags* mask. **enum changelog\_send\_flag** values: ``` CHANGELOG_FLAG_FOLLOW CHANGELOG_FLAG_BLOCK CHANGELOG_FLAG_JOBID CHANGELOG_FLAG_EXTRA_FLAGS ``` [CHANGELOG\_FLAG\_FOLLOW](#CHANGELOG_FLAG_FOLLOW) Use changelog follow mode: **llapi\_changelog\_recv()** will not return when all records have been read. Instead it will block until a new record is available. It avoids restarting an instance and re-scan for newer changelogs. [CHANGELOG\_FLAG\_BLOCK](#CHANGELOG_FLAG_BLOCK) Deprecated since Lustre 2.10. [CHANGELOG\_FLAG\_JOBID](#CHANGELOG_FLAG_JOBID) Pack jobid into the changelog records if available. [CHANGELOG\_FLAG\_EXTRA\_FLAG](#CHANGELOG_FLAG_EXTRA_FLAG) Pack additional flag bits into the changelog record. The function **llapi\_changelog\_start\_user()** , similar to the function **llapi\_changelog\_start()** , initializes a new instance *priv* to read MDT changelogs, but with user-specific filtering, including username and mask. The *username* parameter specifies the changelog username or ID, e.g. "cl1", "cl1-user", "1", or "user". The *mask* parameter specifies the filtering mask in numeric form. If *mask* is 0, the user's registered *MASK* specified to [**lctl-changelog\_register**(8)](/man/enterprise-packages/lustre/lctl-changelog_register.8) will be used. The function **llapi\_changelog\_set\_xflags()** specifies additional changelog flags with *extra\_flags* mask for the instance *priv*. To use those extra flags, CHANGELOG\_FLAG\_EXTRA\_FLAG must be set by **llapi\_changelog\_start()** on *flags* parameter. **enum changelog\_send\_extra\_flag** values: ``` CHANGELOG_EXTRA_FLAG_UIDGID CHANGELOG_EXTRA_FLAG_NID CHANGELOG_EXTRA_FLAG_OMODE CHANGELOG_EXTRA_FLAG_XATTR ``` [CHANGELOG\_EXTRA\_FLAG\_UIDGID](#CHANGELOG_EXTRA_FLAG_UIDGID) Pack uid/gid into the changelog record [CHANGELOG\_EXTRA\_FLAG\_NID](#CHANGELOG_EXTRA_FLAG_NID) Pack nid into the changelog record [CHANGELOG\_EXTRA\_FLAG\_OMODE](#CHANGELOG_EXTRA_FLAG_OMODE) Pack open mode into the changelog record [CHANGELOG\_EXTRA\_FLAG\_XATTR](#CHANGELOG_EXTRA_FLAG_XATTR) Pack xattr name into the changelog record The function **llapi\_changelog\_fini()** closes the MDT's changelog char device and free internal pointers for the instance *priv*. # [RETURN VALUES](#RETURN_VALUES) Return 0 on success or a negative errno value on failure. # [ERRORS](#ERRORS) -ENOMEM Insufficient memory to complete operation. -EINVAL One or more invalid arguments are given. -ENOENT MDT's changelog char device not found. Is the Lustre FS mounted? -EACCES Not enough permissions to open the changelog char device. By default, the device is only accessible to the root user. # [EXAMPLE](#EXAMPLE) To register a user to watch file and directory creation and removal: ``` char *mdd = "testfs-MDT0000"; long long startrec = 0; char *name = "dirwatch"; char *mask_str = "rmdir,mkdir,creat,unlnk"; __u64 mask = CHANGELOG_DEFMASK; void *changelog_priv; struct changelog_rec *rec; /* convert mask string to numeric value */ rc = llapi_convert_str2mask(mask_str, changelog_type2str, &mask, CHANGELOG_MINMASK, CHANGELOG_ALLMASK, CHANGELOG_DEFMASK); /* register a new Changelog consumer with a name and mask */ rc = llapi_changelog_start_user(&changelog_priv, CHANGELOG_FLAG_BLOCK | CHANGELOG_FLAG_EXTRA_FLAGS | CHANGELOG_FLAG_NID_BE | CHANGELOG_FLAG_JOBID, mdd, name, mask, startrec); rc = llapi_changelog_set_xflags(changelog_priv, CHANGELOG_EXTRA_FLAG_UIDGID | CHANGELOG_EXTRA_FLAG_NID | CHANGELOG_EXTRA_FLAG_OMODE | CHANGELOG_EXTRA_FLAG_XATTR); while ((rc = llapi_changelog_recv(changelog_priv, &rec)) == 0) { /* process changelog records */ llapi_changelog_free(&rec); } llapi_changelog_fini(&changelog_priv); ``` # [AVAILABILITY](#AVAILABILITY) **llapi\_changelog\_start()** and **llapi\_changelog\_fini()** are part of the [**lustre**(7)](/man/enterprise-packages/lustre/lustre.7) user application interface library since release 2.0.0, **llapi\_changelog\_set\_xflags()** since release 2.11.0, and **llapi\_changelog\_start\_user()** since release 2.18.0. # [SEE ALSO](#SEE_ALSO) [**lfs-changelog**(1)](/man/enterprise-packages/lustre/lfs-changelog.1), [**llapi\_changelog\_clear**(3)](/man/enterprise-packages/lustre/llapi_changelog_clear.3), [**llapi\_changelog\_deregister**(3)](/man/enterprise-packages/lustre/llapi_changelog_deregister.3), [**llapi\_changelog\_get\_fd**(3)](/man/enterprise-packages/lustre/llapi_changelog_get_fd.3), [**llapi\_changelog\_in\_buf**(3)](/man/enterprise-packages/lustre/llapi_changelog_in_buf.3), [**llapi\_changelog\_recv**(3)](/man/enterprise-packages/lustre/llapi_changelog_recv.3), [**llapi\_changelog\_register**(3)](/man/enterprise-packages/lustre/llapi_changelog_register.3), [**llapi\_convert\_str2mask**(3)](/man/enterprise-packages/lustre/llapi_convert_str2mask.3), [**lustreapi**(7)](/man/enterprise-packages/lustre/lustreapi.7) 2026-09-12 Lustre User API --- Document: llapi_changelog_fini(3) from lustre 2.17.60-r0 (Chainguard OS) Source: https://github.com/lustre/lustre-release