1 files changed, 144 insertions, 214 deletions

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 76566c2cbf63..25a4b82c183c 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -4,14 +4,12 @@
  *             https://www.huawei.com/
  */
 #include "internal.h"
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
 #include <trace/events/erofs.h>
 
 struct z_erofs_maprecorder {
 	struct inode *inode;
 	struct erofs_map_blocks *map;
-	void *kaddr;
-
 	unsigned long lcn;
 	/* compression extent information gathered */
 	u8  type, headtype;
@@ -31,22 +29,17 @@ static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m,
 			vi->inode_isize + vi->xattr_isize) +
 			lcn * sizeof(struct z_erofs_lcluster_index);
 	struct z_erofs_lcluster_index *di;
-	unsigned int advise, type;
-
-	m->kaddr = erofs_read_metabuf(&m->map->buf, inode->i_sb,
-				      erofs_blknr(inode->i_sb, pos), EROFS_KMAP);
-	if (IS_ERR(m->kaddr))
-		return PTR_ERR(m->kaddr);
+	unsigned int advise;
 
-	m->nextpackoff = pos + sizeof(struct z_erofs_lcluster_index);
+	di = erofs_read_metabuf(&m->map->buf, inode->i_sb, pos, EROFS_KMAP);
+	if (IS_ERR(di))
+		return PTR_ERR(di);
 	m->lcn = lcn;
-	di = m->kaddr + erofs_blkoff(inode->i_sb, pos);
+	m->nextpackoff = pos + sizeof(struct z_erofs_lcluster_index);
 
 	advise = le16_to_cpu(di->di_advise);
-	type = (advise >> Z_EROFS_LI_LCLUSTER_TYPE_BIT) &
-		((1 << Z_EROFS_LI_LCLUSTER_TYPE_BITS) - 1);
-	switch (type) {
-	case Z_EROFS_LCLUSTER_TYPE_NONHEAD:
+	m->type = advise & Z_EROFS_LI_LCLUSTER_TYPE_MASK;
+	if (m->type == Z_EROFS_LCLUSTER_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_LI_D0_CBLKCNT) {
@@ -55,29 +48,19 @@ static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m,
 				DBG_BUGON(1);
 				return -EFSCORRUPTED;
 			}
-			m->compressedblks = m->delta[0] &
-				~Z_EROFS_LI_D0_CBLKCNT;
+			m->compressedblks = m->delta[0] & ~Z_EROFS_LI_D0_CBLKCNT;
 			m->delta[0] = 1;
 		}
 		m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
-		break;
-	case Z_EROFS_LCLUSTER_TYPE_PLAIN:
-	case Z_EROFS_LCLUSTER_TYPE_HEAD1:
-	case Z_EROFS_LCLUSTER_TYPE_HEAD2:
-		if (advise & Z_EROFS_LI_PARTIAL_REF)
-			m->partialref = true;
+	} else {
+		m->partialref = !!(advise & Z_EROFS_LI_PARTIAL_REF);
 		m->clusterofs = le16_to_cpu(di->di_clusterofs);
 		if (m->clusterofs >= 1 << vi->z_logical_clusterbits) {
 			DBG_BUGON(1);
 			return -EFSCORRUPTED;
 		}
 		m->pblk = le32_to_cpu(di->di_u.blkaddr);
-		break;
-	default:
-		DBG_BUGON(1);
-		return -EOPNOTSUPP;
 	}
-	m->type = type;
 	return 0;
 }
 
@@ -114,17 +97,48 @@ static int get_compacted_la_distance(unsigned int lobits,
 	return d1;
 }
 
-static int unpack_compacted_index(struct z_erofs_maprecorder *m,
-				  unsigned int amortizedshift,
-				  erofs_off_t pos, bool lookahead)
+static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
+					 unsigned long lcn, bool lookahead)
 {
-	struct erofs_inode *const vi = EROFS_I(m->inode);
+	struct inode *const inode = m->inode;
+	struct erofs_inode *const vi = EROFS_I(inode);
+	const erofs_off_t ebase = sizeof(struct z_erofs_map_header) +
+		ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
-	unsigned int vcnt, base, lo, lobits, encodebits, nblk, eofs;
-	int i;
+	const unsigned int totalidx = erofs_iblks(inode);
+	unsigned int compacted_4b_initial, compacted_2b, amortizedshift;
+	unsigned int vcnt, lo, lobits, encodebits, nblk, bytes;
+	bool big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+	erofs_off_t pos;
 	u8 *in, type;
-	bool big_pcluster;
+	int i;
+
+	if (lcn >= totalidx || lclusterbits > 14)
+		return -EINVAL;
+
+	m->lcn = lcn;
+	/* used to align to 32-byte (compacted_2b) alignment */
+	compacted_4b_initial = ((32 - ebase % 32) / 4) & 7;
+	compacted_2b = 0;
+	if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
+	    compacted_4b_initial < totalidx)
+		compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
+
+	pos = ebase;
+	amortizedshift = 2;	/* compact_4b */
+	if (lcn >= compacted_4b_initial) {
+		pos += compacted_4b_initial * 4;
+		lcn -= compacted_4b_initial;
+		if (lcn < compacted_2b) {
+			amortizedshift = 1;
+		} else {
+			pos += compacted_2b * 2;
+			lcn -= compacted_2b;
+		}
+	}
+	pos += lcn * (1 << amortizedshift);
 
+	/* figure out the lcluster count in this pack */
 	if (1 << amortizedshift == 4 && lclusterbits <= 14)
 		vcnt = 2;
 	else if (1 << amortizedshift == 2 && lclusterbits <= 12)
@@ -132,17 +146,18 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	else
 		return -EOPNOTSUPP;
 
+	in = erofs_read_metabuf(&m->map->buf, m->inode->i_sb, pos, EROFS_KMAP);
+	if (IS_ERR(in))
+		return PTR_ERR(in);
+
 	/* it doesn't equal to round_up(..) */
 	m->nextpackoff = round_down(pos, vcnt << amortizedshift) +
 			 (vcnt << amortizedshift);
-	big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
 	lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1U);
 	encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
-	eofs = erofs_blkoff(m->inode->i_sb, pos);
-	base = round_down(eofs, vcnt << amortizedshift);
-	in = m->kaddr + base;
-
-	i = (eofs - base) >> amortizedshift;
+	bytes = pos & ((vcnt << amortizedshift) - 1);
+	in -= bytes;
+	i = bytes >> amortizedshift;
 
 	lo = decode_compactedbits(lobits, in, encodebits * i, &type);
 	m->type = type;
@@ -222,57 +237,6 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	return 0;
 }
 
-static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
-					 unsigned long lcn, bool lookahead)
-{
-	struct inode *const inode = m->inode;
-	struct erofs_inode *const vi = EROFS_I(inode);
-	const erofs_off_t ebase = sizeof(struct z_erofs_map_header) +
-		ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
-	unsigned int totalidx = erofs_iblks(inode);
-	unsigned int compacted_4b_initial, compacted_2b;
-	unsigned int amortizedshift;
-	erofs_off_t pos;
-
-	if (lcn >= totalidx || vi->z_logical_clusterbits > 14)
-		return -EINVAL;
-
-	m->lcn = lcn;
-	/* used to align to 32-byte (compacted_2b) alignment */
-	compacted_4b_initial = (32 - ebase % 32) / 4;
-	if (compacted_4b_initial == 32 / 4)
-		compacted_4b_initial = 0;
-
-	if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
-	    compacted_4b_initial < totalidx)
-		compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
-	else
-		compacted_2b = 0;
-
-	pos = ebase;
-	if (lcn < compacted_4b_initial) {
-		amortizedshift = 2;
-		goto out;
-	}
-	pos += compacted_4b_initial * 4;
-	lcn -= compacted_4b_initial;
-
-	if (lcn < compacted_2b) {
-		amortizedshift = 1;
-		goto out;
-	}
-	pos += compacted_2b * 2;
-	lcn -= compacted_2b;
-	amortizedshift = 2;
-out:
-	pos += lcn * (1 << amortizedshift);
-	m->kaddr = erofs_read_metabuf(&m->map->buf, inode->i_sb,
-				      erofs_blknr(inode->i_sb, pos), EROFS_KMAP);
-	if (IS_ERR(m->kaddr))
-		return PTR_ERR(m->kaddr);
-	return unpack_compacted_index(m, amortizedshift, pos, lookahead);
-}
-
 static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
 					   unsigned int lcn, bool lookahead)
 {
@@ -301,26 +265,22 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 		if (err)
 			return err;
 
-		switch (m->type) {
-		case Z_EROFS_LCLUSTER_TYPE_NONHEAD:
+		if (m->type >= Z_EROFS_LCLUSTER_TYPE_MAX) {
+			erofs_err(sb, "unknown type %u @ lcn %lu of nid %llu",
+				  m->type, lcn, vi->nid);
+			DBG_BUGON(1);
+			return -EOPNOTSUPP;
+		} else if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
 			lookback_distance = m->delta[0];
 			if (!lookback_distance)
-				goto err_bogus;
+				break;
 			continue;
-		case Z_EROFS_LCLUSTER_TYPE_PLAIN:
-		case Z_EROFS_LCLUSTER_TYPE_HEAD1:
-		case Z_EROFS_LCLUSTER_TYPE_HEAD2:
+		} else {
 			m->headtype = m->type;
 			m->map->m_la = (lcn << lclusterbits) | m->clusterofs;
 			return 0;
-		default:
-			erofs_err(sb, "unknown type %u @ lcn %lu of nid %llu",
-				  m->type, lcn, vi->nid);
-			DBG_BUGON(1);
-			return -EOPNOTSUPP;
 		}
 	}
-err_bogus:
 	erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",
 		  lookback_distance, m->lcn, vi->nid);
 	DBG_BUGON(1);
@@ -330,27 +290,23 @@ err_bogus:
 static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 					    unsigned int initial_lcn)
 {
-	struct super_block *sb = m->inode->i_sb;
-	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;
+	struct inode *inode = m->inode;
+	struct super_block *sb = inode->i_sb;
+	struct erofs_inode *vi = EROFS_I(inode);
+	bool bigpcl1 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+	bool bigpcl2 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2;
+	unsigned long lcn = m->lcn + 1;
 	int err;
 
-	DBG_BUGON(m->type != Z_EROFS_LCLUSTER_TYPE_PLAIN &&
-		  m->type != Z_EROFS_LCLUSTER_TYPE_HEAD1 &&
-		  m->type != Z_EROFS_LCLUSTER_TYPE_HEAD2);
+	DBG_BUGON(m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
 	DBG_BUGON(m->type != m->headtype);
 
-	if (m->headtype == Z_EROFS_LCLUSTER_TYPE_PLAIN ||
-	    ((m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD1) &&
-	     !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) ||
-	    ((m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2) &&
-	     !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
-		map->m_plen = 1ULL << lclusterbits;
-		return 0;
-	}
-	lcn = m->lcn + 1;
+	if ((m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD1 && !bigpcl1) ||
+	    ((m->headtype == Z_EROFS_LCLUSTER_TYPE_PLAIN ||
+	      m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2) && !bigpcl2) ||
+	    (lcn << vi->z_logical_clusterbits) >= inode->i_size)
+		m->compressedblks = 1;
+
 	if (m->compressedblks)
 		goto out;
 
@@ -369,35 +325,28 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 	DBG_BUGON(lcn == initial_lcn &&
 		  m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
 
-	switch (m->type) {
-	case Z_EROFS_LCLUSTER_TYPE_PLAIN:
-	case Z_EROFS_LCLUSTER_TYPE_HEAD1:
-	case Z_EROFS_LCLUSTER_TYPE_HEAD2:
+	if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+		if (m->delta[0] != 1) {
+			erofs_err(sb, "bogus CBLKCNT @ lcn %lu of nid %llu", lcn, vi->nid);
+			DBG_BUGON(1);
+			return -EFSCORRUPTED;
+		}
+		if (m->compressedblks)
+			goto out;
+	} else if (m->type < Z_EROFS_LCLUSTER_TYPE_MAX) {
 		/*
 		 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
-		 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
+		 * rather than CBLKCNT, it's a 1 block-sized pcluster.
 		 */
-		m->compressedblks = 1 << (lclusterbits - sb->s_blocksize_bits);
-		break;
-	case Z_EROFS_LCLUSTER_TYPE_NONHEAD:
-		if (m->delta[0] != 1)
-			goto err_bonus_cblkcnt;
-		if (m->compressedblks)
-			break;
-		fallthrough;
-	default:
-		erofs_err(sb, "cannot found CBLKCNT @ lcn %lu of nid %llu", lcn,
-			  vi->nid);
-		DBG_BUGON(1);
-		return -EFSCORRUPTED;
+		m->compressedblks = 1;
+		goto out;
 	}
-out:
-	map->m_plen = erofs_pos(sb, m->compressedblks);
-	return 0;
-err_bonus_cblkcnt:
-	erofs_err(sb, "bogus CBLKCNT @ lcn %lu of nid %llu", lcn, vi->nid);
+	erofs_err(sb, "cannot found CBLKCNT @ lcn %lu of nid %llu", lcn, vi->nid);
 	DBG_BUGON(1);
 	return -EFSCORRUPTED;
+out:
+	m->map->m_plen = erofs_pos(sb, m->compressedblks);
+	return 0;
 }
 
 static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
@@ -426,9 +375,7 @@ static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
 				m->delta[1] = 1;
 				DBG_BUGON(1);
 			}
-		} else if (m->type == Z_EROFS_LCLUSTER_TYPE_PLAIN ||
-			   m->type == Z_EROFS_LCLUSTER_TYPE_HEAD1 ||
-			   m->type == Z_EROFS_LCLUSTER_TYPE_HEAD2) {
+		} else if (m->type < Z_EROFS_LCLUSTER_TYPE_MAX) {
 			if (lcn != headlcn)
 				break;	/* ends at the next HEAD lcluster */
 			m->delta[1] = 1;
@@ -447,9 +394,10 @@ static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
 static int z_erofs_do_map_blocks(struct inode *inode,
 				 struct erofs_map_blocks *map, int flags)
 {
-	struct erofs_inode *const vi = EROFS_I(inode);
-	bool ztailpacking = vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER;
+	struct erofs_inode *vi = EROFS_I(inode);
+	struct super_block *sb = inode->i_sb;
 	bool fragment = vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
+	bool ztailpacking = vi->z_idata_size;
 	struct z_erofs_maprecorder m = {
 		.inode = inode,
 		.map = map,
@@ -468,9 +416,8 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 	if (err)
 		goto unmap_out;
 
-	if (ztailpacking && (flags & EROFS_GET_BLOCKS_FINDTAIL))
-		vi->z_idataoff = m.nextpackoff;
-
+	if ((flags & EROFS_GET_BLOCKS_FINDTAIL) && ztailpacking)
+		vi->z_fragmentoff = m.nextpackoff;
 	map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_ENCODED;
 	end = (m.lcn + 1ULL) << lclusterbits;
 
@@ -492,8 +439,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 		}
 		/* m.lcn should be >= 1 if endoff < m.clusterofs */
 		if (!m.lcn) {
-			erofs_err(inode->i_sb,
-				  "invalid logical cluster 0 at nid %llu",
+			erofs_err(sb, "invalid logical cluster 0 at nid %llu",
 				  vi->nid);
 			err = -EFSCORRUPTED;
 			goto unmap_out;
@@ -509,8 +455,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 			goto unmap_out;
 		break;
 	default:
-		erofs_err(inode->i_sb,
-			  "unknown type %u @ offset %llu of nid %llu",
+		erofs_err(sb, "unknown type %u @ offset %llu of nid %llu",
 			  m.type, ofs, vi->nid);
 		err = -EOPNOTSUPP;
 		goto unmap_out;
@@ -527,12 +472,18 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 	}
 	if (ztailpacking && m.lcn == vi->z_tailextent_headlcn) {
 		map->m_flags |= EROFS_MAP_META;
-		map->m_pa = vi->z_idataoff;
+		map->m_pa = vi->z_fragmentoff;
 		map->m_plen = vi->z_idata_size;
+		if (erofs_blkoff(sb, map->m_pa) + map->m_plen > sb->s_blocksize) {
+			erofs_err(sb, "invalid tail-packing pclustersize %llu",
+				  map->m_plen);
+			err = -EFSCORRUPTED;
+			goto unmap_out;
+		}
 	} else if (fragment && m.lcn == vi->z_tailextent_headlcn) {
-		map->m_flags |= EROFS_MAP_FRAGMENT;
+		map->m_flags = EROFS_MAP_FRAGMENT;
 	} else {
-		map->m_pa = erofs_pos(inode->i_sb, m.pblk);
+		map->m_pa = erofs_pos(sb, m.pblk);
 		err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
 		if (err)
 			goto unmap_out;
@@ -551,7 +502,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 		afmt = m.headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2 ?
 			vi->z_algorithmtype[1] : vi->z_algorithmtype[0];
 		if (!(EROFS_I_SB(inode)->available_compr_algs & (1 << afmt))) {
-			erofs_err(inode->i_sb, "inconsistent algorithmtype %u for nid %llu",
+			erofs_err(sb, "inconsistent algorithmtype %u for nid %llu",
 				  afmt, vi->nid);
 			err = -EFSCORRUPTED;
 			goto unmap_out;
@@ -562,7 +513,8 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 	if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
 	    ((flags & EROFS_GET_BLOCKS_READMORE) &&
 	     (map->m_algorithmformat == Z_EROFS_COMPRESSION_LZMA ||
-	      map->m_algorithmformat == Z_EROFS_COMPRESSION_DEFLATE) &&
+	      map->m_algorithmformat == Z_EROFS_COMPRESSION_DEFLATE ||
+	      map->m_algorithmformat == Z_EROFS_COMPRESSION_ZSTD) &&
 	      map->m_llen >= i_blocksize(inode))) {
 		err = z_erofs_get_extent_decompressedlen(&m);
 		if (!err)
@@ -581,7 +533,6 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 	int err, headnr;
 	erofs_off_t pos;
 	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-	void *kaddr;
 	struct z_erofs_map_header *h;
 
 	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
@@ -601,13 +552,12 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		goto out_unlock;
 
 	pos = ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
-	kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(sb, pos), EROFS_KMAP);
-	if (IS_ERR(kaddr)) {
-		err = PTR_ERR(kaddr);
+	h = erofs_read_metabuf(&buf, sb, pos, EROFS_KMAP);
+	if (IS_ERR(h)) {
+		err = PTR_ERR(h);
 		goto out_unlock;
 	}
 
-	h = kaddr + erofs_blkoff(sb, pos);
 	/*
 	 * if the highest bit of the 8-byte map header is set, the whole file
 	 * is stored in the packed inode. The rest bits keeps z_fragmentoff.
@@ -621,6 +571,10 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 	vi->z_advise = le16_to_cpu(h->h_advise);
 	vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
 	vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
+	if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)
+		vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
+	else if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER)
+		vi->z_idata_size = le16_to_cpu(h->h_idata_size);
 
 	headnr = 0;
 	if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX ||
@@ -649,33 +603,12 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 		goto out_put_metabuf;
 	}
 
-	if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER) {
-		struct erofs_map_blocks map = {
-			.buf = __EROFS_BUF_INITIALIZER
-		};
-
-		vi->z_idata_size = le16_to_cpu(h->h_idata_size);
-		err = z_erofs_do_map_blocks(inode, &map,
-					    EROFS_GET_BLOCKS_FINDTAIL);
-		erofs_put_metabuf(&map.buf);
-
-		if (!map.m_plen ||
-		    erofs_blkoff(sb, map.m_pa) + map.m_plen > sb->s_blocksize) {
-			erofs_err(sb, "invalid tail-packing pclustersize %llu",
-				  map.m_plen);
-			err = -EFSCORRUPTED;
-		}
-		if (err < 0)
-			goto out_put_metabuf;
-	}
-
-	if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER &&
-	    !(h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT)) {
+	if (vi->z_idata_size ||
+	    (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)) {
 		struct erofs_map_blocks map = {
 			.buf = __EROFS_BUF_INITIALIZER
 		};
 
-		vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
 		err = z_erofs_do_map_blocks(inode, &map,
 					    EROFS_GET_BLOCKS_FINDTAIL);
 		erofs_put_metabuf(&map.buf);
@@ -699,34 +632,31 @@ int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 	struct erofs_inode *const vi = EROFS_I(inode);
 	int err = 0;
 
-	trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
-
-	/* when trying to read beyond EOF, leave it unmapped */
-	if (map->m_la >= inode->i_size) {
+	trace_erofs_map_blocks_enter(inode, map, flags);
+	if (map->m_la >= inode->i_size) {	/* post-EOF unmapped extent */
 		map->m_llen = map->m_la + 1 - inode->i_size;
 		map->m_la = inode->i_size;
 		map->m_flags = 0;
-		goto out;
-	}
-
-	err = z_erofs_fill_inode_lazy(inode);
-	if (err)
-		goto out;
-
-	if ((vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER) &&
-	    !vi->z_tailextent_headlcn) {
-		map->m_la = 0;
-		map->m_llen = inode->i_size;
-		map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_FULL_MAPPED |
-				EROFS_MAP_FRAGMENT;
-		goto out;
+	} else {
+		err = z_erofs_fill_inode_lazy(inode);
+		if (!err) {
+			if ((vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER) &&
+			    !vi->z_tailextent_headlcn) {
+				map->m_la = 0;
+				map->m_llen = inode->i_size;
+				map->m_flags = EROFS_MAP_FRAGMENT;
+			} else {
+				err = z_erofs_do_map_blocks(inode, map, flags);
+			}
+		}
+		if (!err && (map->m_flags & EROFS_MAP_ENCODED) &&
+		    unlikely(map->m_plen > Z_EROFS_PCLUSTER_MAX_SIZE ||
+			     map->m_llen > Z_EROFS_PCLUSTER_MAX_DSIZE))
+			err = -EOPNOTSUPP;
+		if (err)
+			map->m_llen = 0;
 	}
-
-	err = z_erofs_do_map_blocks(inode, map, flags);
-out:
-	if (err)
-		map->m_llen = 0;
-	trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
+	trace_erofs_map_blocks_exit(inode, map, flags, err);
 	return err;
 }
 
@@ -747,7 +677,7 @@ static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
 	iomap->length = map.m_llen;
 	if (map.m_flags & EROFS_MAP_MAPPED) {
 		iomap->type = IOMAP_MAPPED;
-		iomap->addr = map.m_flags & EROFS_MAP_FRAGMENT ?
+		iomap->addr = map.m_flags & __EROFS_MAP_FRAGMENT ?
 			      IOMAP_NULL_ADDR : map.m_pa;
 	} else {
 		iomap->type = IOMAP_HOLE;