[PATCH] erofs: clean up header parsing for ztailpacking and fragments

[Gao Xiang]

Simplify the logic in z_erofs_fill_inode_lazy() by combining the
handling of ztailpacking and fragments, as they are mutually exclusive.

Note that `h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT` is handled
above, so no need to duplicate the check.

Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 fs/erofs/zmap.c | 47 +++++++++++++++++++----------------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index a0c1c6450a55..bdac20800ded 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -394,7 +394,8 @@ 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);
+	struct erofs_inode *vi = EROFS_I(inode);
+	struct super_block *sb = inode->i_sb;
 	bool ztailpacking = vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER;
 	bool fragment = vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
 	struct z_erofs_maprecorder m = {
@@ -439,7 +440,7 @@ 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;
@@ -455,7 +456,7 @@ 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;
@@ -474,10 +475,17 @@ static int z_erofs_do_map_blocks(struct inode *inode,
 		map->m_flags |= EROFS_MAP_META;
 		map->m_pa = vi->z_idataoff;
 		map->m_plen = vi->z_idata_size;
+		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;
+			goto unmap_out;
+		}
 	} else if (fragment && m.lcn == vi->z_tailextent_headlcn) {
 		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;
@@ -496,7 +504,7 @@ 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;
@@ -593,33 +601,16 @@ 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_advise & (Z_EROFS_ADVISE_INLINE_PCLUSTER |
+			    Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)) {
 		struct erofs_map_blocks map = {
 			.buf = __EROFS_BUF_INITIALIZER
 		};
 
-		vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
+		if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER)
+			vi->z_idata_size = le16_to_cpu(h->h_idata_size);
+		else
+			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);
-- 
2.43.5