1 // SPDX-License-Identifier: GPL-2.0+
24  * The basics of filesystem summary counter checking are that we iterate the
25  * AGs counting the number of free blocks, free space btree blocks, per-AG
27  * Then we compare what we computed against the in-core counters.
32  * freezing is costly.  To get around this, we added a per-cpu counter of the
37  * So the first thing we do is warm up the buffer cache in the setup routine by
38  * walking all the AGs to make sure the incore per-AG structure has been
39  * initialized.  The expected value calculation then iterates the incore per-AG
41  * after this operation and use the difference in counter values to guess at
42  * our tolerance for mismatch between expected and actual counter values.
53  * Make sure the per-AG structure has been initialized from the on-disk header
66 	struct xfs_mount	*mp = sc->mp;  in xchk_fscount_warmup()
73 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {  in xchk_fscount_warmup()
76 		if (pag->pagi_init && pag->pagf_init)  in xchk_fscount_warmup()
80 		error = xfs_ialloc_read_agi(mp, sc->tp, agno, &agi_bp);  in xchk_fscount_warmup()
83 		error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, &agf_bp);  in xchk_fscount_warmup()
91 		error = -EFSCORRUPTED;  in xchk_fscount_warmup()
92 		if (!pag->pagi_init || !pag->pagf_init)  in xchk_fscount_warmup()
125 	sc->buf = kmem_zalloc(sizeof(struct xchk_fscounters), 0);  in xchk_setup_fscounters()
126 	if (!sc->buf)  in xchk_setup_fscounters()
127 		return -ENOMEM;  in xchk_setup_fscounters()
128 	fsc = sc->buf;  in xchk_setup_fscounters()
130 	xfs_icount_range(sc->mp, &fsc->icount_min, &fsc->icount_max);  in xchk_setup_fscounters()
132 	/* We must get the incore counters set up before we can proceed. */  in xchk_setup_fscounters()
148  * Calculate what the global in-core counters ought to be from the incore
149  * per-AG structure.  Callers can compare this to the actual in-core counters
150  * to estimate by how much both in-core and on-disk counters need to be
158 	struct xfs_mount	*mp = sc->mp;  in xchk_fscount_aggregate_agcounts()
166 	fsc->icount = 0;  in xchk_fscount_aggregate_agcounts()
167 	fsc->ifree = 0;  in xchk_fscount_aggregate_agcounts()
168 	fsc->fdblocks = 0;  in xchk_fscount_aggregate_agcounts()
170 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {  in xchk_fscount_aggregate_agcounts()
174 		if (!pag->pagi_init || !pag->pagf_init) {  in xchk_fscount_aggregate_agcounts()
176 			return -EFSCORRUPTED;  in xchk_fscount_aggregate_agcounts()
180 		fsc->icount += pag->pagi_count;  in xchk_fscount_aggregate_agcounts()
181 		fsc->ifree += pag->pagi_freecount;  in xchk_fscount_aggregate_agcounts()
183 		/* Add up the free/freelist/bnobt/cntbt blocks */  in xchk_fscount_aggregate_agcounts()
184 		fsc->fdblocks += pag->pagf_freeblks;  in xchk_fscount_aggregate_agcounts()
185 		fsc->fdblocks += pag->pagf_flcount;  in xchk_fscount_aggregate_agcounts()
186 		fsc->fdblocks += pag->pagf_btreeblks;  in xchk_fscount_aggregate_agcounts()
189 		 * Per-AG reservations are taken out of the incore counters,  in xchk_fscount_aggregate_agcounts()
192 		fsc->fdblocks -= pag->pag_meta_resv.ar_reserved;  in xchk_fscount_aggregate_agcounts()
193 		fsc->fdblocks -= pag->pag_rmapbt_resv.ar_orig_reserved;  in xchk_fscount_aggregate_agcounts()
208 	fsc->fdblocks -= mp->m_resblks_avail;  in xchk_fscount_aggregate_agcounts()
215 	delayed = percpu_counter_sum(&mp->m_delalloc_blks);  in xchk_fscount_aggregate_agcounts()
216 	fsc->fdblocks -= delayed;  in xchk_fscount_aggregate_agcounts()
218 	trace_xchk_fscounters_calc(mp, fsc->icount, fsc->ifree, fsc->fdblocks,  in xchk_fscount_aggregate_agcounts()
223 	if (fsc->icount < fsc->icount_min || fsc->icount > fsc->icount_max ||  in xchk_fscount_aggregate_agcounts()
224 	    fsc->fdblocks > mp->m_sb.sb_dblocks ||  in xchk_fscount_aggregate_agcounts()
225 	    fsc->ifree > fsc->icount_max)  in xchk_fscount_aggregate_agcounts()
226 		return -EFSCORRUPTED;  in xchk_fscount_aggregate_agcounts()
231 	 * to maintain ifree <= icount before giving up.  in xchk_fscount_aggregate_agcounts()
233 	if (fsc->ifree > fsc->icount) {  in xchk_fscount_aggregate_agcounts()
234 		if (tries--)  in xchk_fscount_aggregate_agcounts()
244  * Is the @counter reasonably close to the @expected value?
247  * per-AG data to compute the @expected value, which means that the counter
248  * could have changed.  We know the @old_value of the summation of the counter
249  * before the aggregation, and we re-sum the counter now.  If the expected
260 	struct percpu_counter	*counter,  in xchk_fscount_within_range()  argument
264 	int64_t			curr_value = percpu_counter_sum(counter);  in xchk_fscount_within_range()
266 	trace_xchk_fscounters_within_range(sc->mp, expected, curr_value,  in xchk_fscount_within_range()
280 	/* Within the before-and-after range is ok. */  in xchk_fscount_within_range()
287 	 * true here so that we don't mark the counter corrupt.  in xchk_fscount_within_range()
291 	 * check should be moved up and the return code changed to signal to  in xchk_fscount_within_range()
294 	if (max_value - min_value >= XCHK_FSCOUNT_MIN_VARIANCE) {  in xchk_fscount_within_range()
307 	struct xfs_mount	*mp = sc->mp;  in xchk_fscounters()
308 	struct xchk_fscounters	*fsc = sc->buf;  in xchk_fscounters()
313 	icount = percpu_counter_sum(&mp->m_icount);  in xchk_fscounters()
314 	ifree = percpu_counter_sum(&mp->m_ifree);  in xchk_fscounters()
315 	fdblocks = percpu_counter_sum(&mp->m_fdblocks);  in xchk_fscounters()
322 	if (icount < fsc->icount_min || icount > fsc->icount_max)  in xchk_fscounters()
326 	if (fdblocks > mp->m_sb.sb_dblocks)  in xchk_fscounters()
333 	if (ifree > icount && ifree - icount > XCHK_FSCOUNT_MIN_VARIANCE)  in xchk_fscounters()
340 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE)  in xchk_fscounters()
343 	/* Compare the in-core counters with whatever we counted. */  in xchk_fscounters()
344 	if (!xchk_fscount_within_range(sc, icount, &mp->m_icount, fsc->icount))  in xchk_fscounters()
347 	if (!xchk_fscount_within_range(sc, ifree, &mp->m_ifree, fsc->ifree))  in xchk_fscounters()
350 	if (!xchk_fscount_within_range(sc, fdblocks, &mp->m_fdblocks,  in xchk_fscounters()
351 			fsc->fdblocks))  in xchk_fscounters()