erofs: clean up header parsing for ztailpacking and fragments

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.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250224123747.1387122-2-hsiangkao@linux.alibaba.com

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index ba4533eabc6a29e711f6393d03409bbc8dbfe333..87f933268ac7245465f6d5b6b7c5eee11026e509 100644 (file)
--- 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 fragment = vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
        bool ztailpacking = vi->z_idata_size;
        struct z_erofs_maprecorder m = {
@@ -438,7 +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;
@@ -454,7 +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;
@@ -473,10 +474,16 @@ static int z_erofs_do_map_blocks(struct inode *inode,
                map->m_flags |= EROFS_MAP_META;
                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;
        } 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;
@@ -495,7 +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;
@@ -596,26 +603,8 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
                goto out_put_metabuf;
        }
 
-       if (vi->z_idata_size) {
-               struct erofs_map_blocks map = {
-                       .buf = __EROFS_BUF_INITIALIZER
-               };
-
-               err = z_erofs_do_map_blocks(inode, &map,
-                                           EROFS_GET_BLOCKS_FINDTAIL);
-               erofs_put_metabuf(&map.buf);
-
-               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;
-               }
-               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
                };