1 files changed, 151 insertions, 30 deletions

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 14d2de35110c..efaf32596b97 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -11,17 +11,16 @@
 int z_erofs_fill_inode(struct inode *inode)
 {
 	struct erofs_inode *const vi = EROFS_I(inode);
+	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 
-	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
+	if (!erofs_sb_has_big_pcluster(sbi) &&
+	    vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
 		vi->z_advise = 0;
 		vi->z_algorithmtype[0] = 0;
 		vi->z_algorithmtype[1] = 0;
 		vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
-		vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
-		vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
 		set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
 	}
-
 	inode->i_mapping->a_ops = &z_erofs_aops;
 	return 0;
 }
@@ -52,7 +51,8 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
-	DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+	DBG_BUGON(!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
+		  vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
 
 	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 		    vi->xattr_isize, 8);
@@ -77,18 +77,22 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 	}
 
 	vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
-	vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits +
-					((h->h_clusterbits >> 3) & 3);
-
-	if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
-		erofs_err(sb, "unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
-			  vi->z_physical_clusterbits[0], vi->nid);
-		err = -EOPNOTSUPP;
+	if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
+	    vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+			    Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+		erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
+			  vi->nid);
+		err = -EFSCORRUPTED;
+		goto unmap_done;
+	}
+	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+		erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+			  vi->nid);
+		err = -EFSCORRUPTED;
 		goto unmap_done;
 	}
-
-	vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
-					((h->h_clusterbits >> 5) & 7);
 	/* paired with smp_mb() at the beginning of the function */
 	smp_mb();
 	set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
@@ -111,7 +115,7 @@ struct z_erofs_maprecorder {
 	u8  type;
 	u16 clusterofs;
 	u16 delta[2];
-	erofs_blk_t pblk;
+	erofs_blk_t pblk, compressedlcs;
 };
 
 static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
@@ -174,6 +178,15 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 		m->clusterofs = 1 << vi->z_logical_clusterbits;
 		m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
+		if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = m->delta[0] &
+				~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+		}
 		m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
 		break;
 	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
@@ -210,6 +223,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	unsigned int vcnt, base, lo, encodebits, nblk;
 	int i;
 	u8 *in, type;
+	bool big_pcluster;
 
 	if (1 << amortizedshift == 4)
 		vcnt = 2;
@@ -218,6 +232,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	else
 		return -EOPNOTSUPP;
 
+	big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
 	encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
 	base = round_down(eofs, vcnt << amortizedshift);
 	in = m->kaddr + base;
@@ -229,7 +244,15 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	m->type = type;
 	if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
 		m->clusterofs = 1 << lclusterbits;
-		if (i + 1 != vcnt) {
+		if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!big_pcluster) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+			return 0;
+		} else if (i + 1 != (int)vcnt) {
 			m->delta[0] = lo;
 			return 0;
 		}
@@ -242,22 +265,48 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 					  in, encodebits * (i - 1), &type);
 		if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
 			lo = 0;
+		else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
+			lo = 1;
 		m->delta[0] = lo + 1;
 		return 0;
 	}
 	m->clusterofs = lo;
 	m->delta[0] = 0;
 	/* figout out blkaddr (pblk) for HEAD lclusters */
-	nblk = 1;
-	while (i > 0) {
-		--i;
-		lo = decode_compactedbits(lclusterbits, lomask,
-					  in, encodebits * i, &type);
-		if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
-			i -= lo;
-
-		if (i >= 0)
+	if (!big_pcluster) {
+		nblk = 1;
+		while (i > 0) {
+			--i;
+			lo = decode_compactedbits(lclusterbits, lomask,
+						  in, encodebits * i, &type);
+			if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+				i -= lo;
+
+			if (i >= 0)
+				++nblk;
+		}
+	} else {
+		nblk = 0;
+		while (i > 0) {
+			--i;
+			lo = decode_compactedbits(lclusterbits, lomask,
+						  in, encodebits * i, &type);
+			if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+				if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+					--i;
+					nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+					continue;
+				}
+				/* bigpcluster shouldn't have plain d0 == 1 */
+				if (lo <= 1) {
+					DBG_BUGON(1);
+					return -EFSCORRUPTED;
+				}
+				i -= lo - 2;
+				continue;
+			}
 			++nblk;
+		}
 	}
 	in += (vcnt << amortizedshift) - sizeof(__le32);
 	m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
@@ -381,6 +430,75 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 	return 0;
 }
 
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+					    unsigned int initial_lcn)
+{
+	struct erofs_inode *const vi = EROFS_I(m->inode);
+	struct erofs_map_blocks *const map = m->map;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	unsigned long lcn;
+	int err;
+
+	DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
+		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
+	if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+		map->m_plen = 1 << lclusterbits;
+		return 0;
+	}
+
+	lcn = m->lcn + 1;
+	if (m->compressedlcs)
+		goto out;
+
+	err = z_erofs_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	/*
+	 * If the 1st NONHEAD lcluster has already been handled initially w/o
+	 * valid compressedlcs, which means at least it mustn't be CBLKCNT, or
+	 * an internal implemenatation error is detected.
+	 *
+	 * The following code can also handle it properly anyway, but let's
+	 * BUG_ON in the debugging mode only for developers to notice that.
+	 */
+	DBG_BUGON(lcn == initial_lcn &&
+		  m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		/*
+		 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
+		 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
+		 */
+		m->compressedlcs = 1;
+		break;
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		if (m->delta[0] != 1)
+			goto err_bonus_cblkcnt;
+		if (m->compressedlcs)
+			break;
+		fallthrough;
+	default:
+		erofs_err(m->inode->i_sb,
+			  "cannot found CBLKCNT @ lcn %lu of nid %llu",
+			  lcn, vi->nid);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+out:
+	map->m_plen = m->compressedlcs << lclusterbits;
+	return 0;
+err_bonus_cblkcnt:
+	erofs_err(m->inode->i_sb,
+		  "bogus CBLKCNT @ lcn %lu of nid %llu",
+		  lcn, vi->nid);
+	DBG_BUGON(1);
+	return -EFSCORRUPTED;
+}
+
 int z_erofs_map_blocks_iter(struct inode *inode,
 			    struct erofs_map_blocks *map,
 			    int flags)
@@ -392,6 +510,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 	};
 	int err = 0;
 	unsigned int lclusterbits, endoff;
+	unsigned long initial_lcn;
 	unsigned long long ofs, end;
 
 	trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
@@ -410,10 +529,10 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 
 	lclusterbits = vi->z_logical_clusterbits;
 	ofs = map->m_la;
-	m.lcn = ofs >> lclusterbits;
+	initial_lcn = ofs >> lclusterbits;
 	endoff = ofs & ((1 << lclusterbits) - 1);
 
-	err = z_erofs_load_cluster_from_disk(&m, m.lcn);
+	err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
 	if (err)
 		goto unmap_out;
 
@@ -443,7 +562,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 		m.delta[0] = 1;
 		fallthrough;
 	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
-		/* get the correspoinding first chunk */
+		/* get the corresponding first chunk */
 		err = z_erofs_extent_lookback(&m, m.delta[0]);
 		if (err)
 			goto unmap_out;
@@ -457,10 +576,12 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 	}
 
 	map->m_llen = end - map->m_la;
-	map->m_plen = 1 << lclusterbits;
 	map->m_pa = blknr_to_addr(m.pblk);
 	map->m_flags |= EROFS_MAP_MAPPED;
 
+	err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+	if (err)
+		goto out;
 unmap_out:
 	if (m.kaddr)
 		kunmap_atomic(m.kaddr);