- * Get file system statistics of OST server.
- *
- * Helper function for ofd_statfs(), also used by grant code.
- * Implements caching for statistics to avoid calling OSD device each time.
- *
- * \param[in] env execution environment
- * \param[in] ofd OFD device
- * \param[out] osfs statistic data to return
- * \param[in] max_age maximum age for cached data
- * \param[in] from_cache show that data was get from cache or not
- *
- * \retval 0 if successful
- * \retval negative value on error
- */
-int ofd_statfs_internal(const struct lu_env *env, struct ofd_device *ofd,
- struct obd_statfs *osfs, __u64 max_age, int *from_cache)
-{
- int rc = 0;
- ENTRY;
-
- spin_lock(&ofd->ofd_osfs_lock);
- if (cfs_time_before_64(ofd->ofd_osfs_age, max_age) || max_age == 0) {
- u64 unstable;
-
- /* statfs data are too old, get up-to-date one.
- * we must be cautious here since multiple threads might be
- * willing to update statfs data concurrently and we must
- * grant that cached statfs data are always consistent */
-
- if (ofd->ofd_statfs_inflight == 0)
- /* clear inflight counter if no users, although it would
- * take a while to overflow this 64-bit counter ... */
- ofd->ofd_osfs_inflight = 0;
- /* notify ofd_grant_commit() that we want to track writes
- * completed as of now */
- ofd->ofd_statfs_inflight++;
- /* record value of inflight counter before running statfs to
- * compute the diff once statfs is completed */
- unstable = ofd->ofd_osfs_inflight;
- spin_unlock(&ofd->ofd_osfs_lock);
-
- /* statfs can sleep ... hopefully not for too long since we can
- * call it fairly often as space fills up */
- rc = dt_statfs(env, ofd->ofd_osd, osfs);
- if (unlikely(rc))
- GOTO(out, rc);
-
- spin_lock(&ofd->ofd_grant_lock);
- spin_lock(&ofd->ofd_osfs_lock);
- /* calculate how much space was written while we released the
- * ofd_osfs_lock */
- unstable = ofd->ofd_osfs_inflight - unstable;
- ofd->ofd_osfs_unstable = 0;
- if (unstable) {
- /* some writes committed while we were running statfs
- * w/o the ofd_osfs_lock. Those ones got added to
- * the cached statfs data that we are about to crunch.
- * Take them into account in the new statfs data */
- osfs->os_bavail -= min_t(u64, osfs->os_bavail,
- unstable >> ofd->ofd_blockbits);
- /* However, we don't really know if those writes got
- * accounted in the statfs call, so tell
- * ofd_grant_space_left() there is some uncertainty
- * on the accounting of those writes.
- * The purpose is to prevent spurious error messages in
- * ofd_grant_space_left() since those writes might be
- * accounted twice. */
- ofd->ofd_osfs_unstable += unstable;
- }
- /* similarly, there is some uncertainty on write requests
- * between prepare & commit */
- ofd->ofd_osfs_unstable += ofd->ofd_tot_pending;
- spin_unlock(&ofd->ofd_grant_lock);
-
- /* finally udpate cached statfs data */
- ofd->ofd_osfs = *osfs;
- ofd->ofd_osfs_age = cfs_time_current_64();
-
- ofd->ofd_statfs_inflight--; /* stop tracking */
- if (ofd->ofd_statfs_inflight == 0)
- ofd->ofd_osfs_inflight = 0;
- spin_unlock(&ofd->ofd_osfs_lock);
-
- if (from_cache)
- *from_cache = 0;
- } else {
- /* use cached statfs data */
- *osfs = ofd->ofd_osfs;
- spin_unlock(&ofd->ofd_osfs_lock);
- if (from_cache)
- *from_cache = 1;
- }
- GOTO(out, rc);
-
-out:
- return rc;
-}
-
-/**