1 // SPDX-License-Identifier: GPL-2.0+
25  * The basics of filesystem summary counter checking are that we iterate the
26  * AGs counting the number of free blocks, free space btree blocks, per-AG
28  * Then we compare what we computed against the in-core counters.
33  * freezing is costly.  To get around this, we added a per-cpu counter of the
38  * So the first thing we do is warm up the buffer cache in the setup routine by
39  * walking all the AGs to make sure the incore per-AG structure has been
40  * initialized.  The expected value calculation then iterates the incore per-AG
42  * after this operation and use the difference in counter values to guess at
43  * our tolerance for mismatch between expected and actual counter values.
54  * Make sure the per-AG structure has been initialized from the on-disk header
67 	struct xfs_mount	*mp = sc->mp;  in xchk_fscount_warmup()
77 		if (pag->pagi_init && pag->pagf_init)  in xchk_fscount_warmup()
81 		error = xfs_ialloc_read_agi(pag, sc->tp, &agi_bp);  in xchk_fscount_warmup()
84 		error = xfs_alloc_read_agf(pag, sc->tp, 0, &agf_bp);  in xchk_fscount_warmup()
92 		if (!pag->pagi_init || !pag->pagf_init) {  in xchk_fscount_warmup()
93 			error = -EFSCORRUPTED;  in xchk_fscount_warmup()
119 	sc->buf = kmem_zalloc(sizeof(struct xchk_fscounters), 0);  in xchk_setup_fscounters()
120 	if (!sc->buf)  in xchk_setup_fscounters()
121 		return -ENOMEM;  in xchk_setup_fscounters()
122 	fsc = sc->buf;  in xchk_setup_fscounters()
124 	xfs_icount_range(sc->mp, &fsc->icount_min, &fsc->icount_max);  in xchk_setup_fscounters()
126 	/* We must get the incore counters set up before we can proceed. */  in xchk_setup_fscounters()
141 /* Count free space btree blocks manually for pre-lazysbcount filesystems. */
151 	error = xchk_ag_init_existing(sc, agno, &sc->sa);  in xchk_fscount_btreeblks()
155 	error = xfs_btree_count_blocks(sc->sa.bno_cur, &blocks);  in xchk_fscount_btreeblks()
158 	fsc->fdblocks += blocks - 1;  in xchk_fscount_btreeblks()
160 	error = xfs_btree_count_blocks(sc->sa.cnt_cur, &blocks);  in xchk_fscount_btreeblks()
163 	fsc->fdblocks += blocks - 1;  in xchk_fscount_btreeblks()
166 	xchk_ag_free(sc, &sc->sa);  in xchk_fscount_btreeblks()
171  * Calculate what the global in-core counters ought to be from the incore
172  * per-AG structure.  Callers can compare this to the actual in-core counters
173  * to estimate by how much both in-core and on-disk counters need to be
181 	struct xfs_mount	*mp = sc->mp;  in xchk_fscount_aggregate_agcounts()
189 	fsc->icount = 0;  in xchk_fscount_aggregate_agcounts()
190 	fsc->ifree = 0;  in xchk_fscount_aggregate_agcounts()
191 	fsc->fdblocks = 0;  in xchk_fscount_aggregate_agcounts()
198 		if (!pag->pagi_init || !pag->pagf_init) {  in xchk_fscount_aggregate_agcounts()
199 			error = -EFSCORRUPTED;  in xchk_fscount_aggregate_agcounts()
204 		fsc->icount += pag->pagi_count;  in xchk_fscount_aggregate_agcounts()
205 		fsc->ifree += pag->pagi_freecount;  in xchk_fscount_aggregate_agcounts()
207 		/* Add up the free/freelist/bnobt/cntbt blocks */  in xchk_fscount_aggregate_agcounts()
208 		fsc->fdblocks += pag->pagf_freeblks;  in xchk_fscount_aggregate_agcounts()
209 		fsc->fdblocks += pag->pagf_flcount;  in xchk_fscount_aggregate_agcounts()
210 		if (xfs_has_lazysbcount(sc->mp)) {  in xchk_fscount_aggregate_agcounts()
211 			fsc->fdblocks += pag->pagf_btreeblks;  in xchk_fscount_aggregate_agcounts()
219 		 * Per-AG reservations are taken out of the incore counters,  in xchk_fscount_aggregate_agcounts()
222 		fsc->fdblocks -= pag->pag_meta_resv.ar_reserved;  in xchk_fscount_aggregate_agcounts()
223 		fsc->fdblocks -= pag->pag_rmapbt_resv.ar_orig_reserved;  in xchk_fscount_aggregate_agcounts()
235 	fsc->fdblocks -= mp->m_resblks_avail;  in xchk_fscount_aggregate_agcounts()
242 	delayed = percpu_counter_sum(&mp->m_delalloc_blks);  in xchk_fscount_aggregate_agcounts()
243 	fsc->fdblocks -= delayed;  in xchk_fscount_aggregate_agcounts()
245 	trace_xchk_fscounters_calc(mp, fsc->icount, fsc->ifree, fsc->fdblocks,  in xchk_fscount_aggregate_agcounts()
250 	if (fsc->icount < fsc->icount_min || fsc->icount > fsc->icount_max ||  in xchk_fscount_aggregate_agcounts()
251 	    fsc->fdblocks > mp->m_sb.sb_dblocks ||  in xchk_fscount_aggregate_agcounts()
252 	    fsc->ifree > fsc->icount_max)  in xchk_fscount_aggregate_agcounts()
253 		return -EFSCORRUPTED;  in xchk_fscount_aggregate_agcounts()
258 	 * to maintain ifree <= icount before giving up.  in xchk_fscount_aggregate_agcounts()
260 	if (fsc->ifree > fsc->icount) {  in xchk_fscount_aggregate_agcounts()
261 		if (tries--)  in xchk_fscount_aggregate_agcounts()
271  * Is the @counter reasonably close to the @expected value?
274  * per-AG data to compute the @expected value, which means that the counter
275  * could have changed.  We know the @old_value of the summation of the counter
276  * before the aggregation, and we re-sum the counter now.  If the expected
287 	struct percpu_counter	*counter,  in xchk_fscount_within_range()  argument
291 	int64_t			curr_value = percpu_counter_sum(counter);  in xchk_fscount_within_range()
293 	trace_xchk_fscounters_within_range(sc->mp, expected, curr_value,  in xchk_fscount_within_range()
307 	/* Within the before-and-after range is ok. */  in xchk_fscount_within_range()
314 	 * true here so that we don't mark the counter corrupt.  in xchk_fscount_within_range()
318 	 * check should be moved up and the return code changed to signal to  in xchk_fscount_within_range()
321 	if (max_value - min_value >= XCHK_FSCOUNT_MIN_VARIANCE) {  in xchk_fscount_within_range()
334 	struct xfs_mount	*mp = sc->mp;  in xchk_fscounters()
335 	struct xchk_fscounters	*fsc = sc->buf;  in xchk_fscounters()
340 	icount = percpu_counter_sum(&mp->m_icount);  in xchk_fscounters()
341 	ifree = percpu_counter_sum(&mp->m_ifree);  in xchk_fscounters()
342 	fdblocks = percpu_counter_sum(&mp->m_fdblocks);  in xchk_fscounters()
349 	if (icount < fsc->icount_min || icount > fsc->icount_max)  in xchk_fscounters()
353 	if (fdblocks > mp->m_sb.sb_dblocks)  in xchk_fscounters()
360 	if (ifree > icount && ifree - icount > XCHK_FSCOUNT_MIN_VARIANCE)  in xchk_fscounters()
367 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE)  in xchk_fscounters()
370 	/* Compare the in-core counters with whatever we counted. */  in xchk_fscounters()
371 	if (!xchk_fscount_within_range(sc, icount, &mp->m_icount, fsc->icount))  in xchk_fscounters()
374 	if (!xchk_fscount_within_range(sc, ifree, &mp->m_ifree, fsc->ifree))  in xchk_fscounters()
377 	if (!xchk_fscount_within_range(sc, fdblocks, &mp->m_fdblocks,  in xchk_fscounters()
378 			fsc->fdblocks))  in xchk_fscounters()