erofs: avoid the potentially wrong m_plen for big pcluster

Actually, 'compressedlcs' stores compressed block count rather than
lcluster count. Therefore, the number of bits for shifting the count
should be 'LOG_BLOCK_SIZE' rather than 'lclusterbits' although current
lcluster size is 4K.

The value of 'm_plen' will be wrong once we enable the non 4K-sized
lcluster.

Signed-off-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20220812060150.8510-1-huyue2@coolpad.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 572f0b8..d58549c 100644 (file)
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -141,7 +141,7 @@ struct z_erofs_maprecorder {
        u8  type, headtype;
        u16 clusterofs;
        u16 delta[2];
-       erofs_blk_t pblk, compressedlcs;
+       erofs_blk_t pblk, compressedblks;
        erofs_off_t nextpackoff;
 };
 
@@ -192,7 +192,7 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
                                DBG_BUGON(1);
                                return -EFSCORRUPTED;
                        }
-                       m->compressedlcs = m->delta[0] &
+                       m->compressedblks = m->delta[0] &
                                ~Z_EROFS_VLE_DI_D0_CBLKCNT;
                        m->delta[0] = 1;
                }
@@ -293,7 +293,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
                                DBG_BUGON(1);
                                return -EFSCORRUPTED;
                        }
-                       m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+                       m->compressedblks = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
                        m->delta[0] = 1;
                        return 0;
                } else if (i + 1 != (int)vcnt) {
@@ -497,7 +497,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
                return 0;
        }
        lcn = m->lcn + 1;
-       if (m->compressedlcs)
+       if (m->compressedblks)
                goto out;
 
        err = z_erofs_load_cluster_from_disk(m, lcn, false);
@@ -506,7 +506,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 
        /*
         * If the 1st NONHEAD lcluster has already been handled initially w/o
-        * valid compressedlcs, which means at least it mustn't be CBLKCNT, or
+        * valid compressedblks, 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
@@ -523,12 +523,12 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
                 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
                 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
                 */
-               m->compressedlcs = 1;
+               m->compressedblks = 1 << (lclusterbits - LOG_BLOCK_SIZE);
                break;
        case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
                if (m->delta[0] != 1)
                        goto err_bonus_cblkcnt;
-               if (m->compressedlcs)
+               if (m->compressedblks)
                        break;
                fallthrough;
        default:
@@ -539,7 +539,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
                return -EFSCORRUPTED;
        }
 out:
-       map->m_plen = (u64)m->compressedlcs << lclusterbits;
+       map->m_plen = (u64)m->compressedblks << LOG_BLOCK_SIZE;
        return 0;
 err_bonus_cblkcnt:
        erofs_err(m->inode->i_sb,