Hello Darrick J. Wong,
The patch 908ce71e54f8: "xfs: allow setting and clearing of log
incompat feature flags" from Aug 8, 2021, leads to the following
Smatch static checker warning:
fs/xfs/xfs_mount.c:1315 xfs_add_incompat_log_feature()
warn: missing error code 'error'
fs/xfs/xfs_mount.c
1280 int
1281 xfs_add_incompat_log_feature(
1282 struct xfs_mount *mp,
1283 uint32_t feature)
1284 {
1285 struct xfs_dsb *dsb;
1286 int error;
1287
1288 ASSERT(hweight32(feature) == 1);
1289 ASSERT(!(feature & XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
1290
1291 /*
1292 * Force the log to disk and kick the background AIL thread to reduce
1293 * the chances that the bwrite will stall waiting for the AIL to unpin
1294 * the primary superblock buffer. This isn't a data integrity
1295 * operation, so we don't need a synchronous push.
1296 */
1297 error = xfs_log_force(mp, XFS_LOG_SYNC);
1298 if (error)
1299 return error;
1300 xfs_ail_push_all(mp->m_ail);
1301
1302 /*
1303 * Lock the primary superblock buffer to serialize all callers that
1304 * are trying to set feature bits.
1305 */
1306 xfs_buf_lock(mp->m_sb_bp);
1307 xfs_buf_hold(mp->m_sb_bp);
1308
1309 if (xfs_is_shutdown(mp)) {
1310 error = -EIO;
1311 goto rele;
1312 }
1313
1314 if (xfs_sb_has_incompat_log_feature(&mp->m_sb, feature))
--> 1315 goto rele;
^^^^^^^^^
It's not clear to me, why this old code is suddenly showing up as a new
warning... But it does feel like it should be an error path.
1316
1317 /*
1318 * Write the primary superblock to disk immediately, because we need
1319 * the log_incompat bit to be set in the primary super now to protect
1320 * the log items that we're going to commit later.
1321 */
1322 dsb = mp->m_sb_bp->b_addr;
1323 xfs_sb_to_disk(dsb, &mp->m_sb);
1324 dsb->sb_features_log_incompat |= cpu_to_be32(feature);
1325 error = xfs_bwrite(mp->m_sb_bp);
1326 if (error)
1327 goto shutdown;
1328
1329 /*
1330 * Add the feature bits to the incore superblock before we unlock the
1331 * buffer.
1332 */
1333 xfs_sb_add_incompat_log_features(&mp->m_sb, feature);
1334 xfs_buf_relse(mp->m_sb_bp);
1335
1336 /* Log the superblock to disk. */
1337 return xfs_sync_sb(mp, false);
1338 shutdown:
1339 xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
1340 rele:
1341 xfs_buf_relse(mp->m_sb_bp);
1342 return error;
1343 }
regards,
dan carpenter
