[PATCH AUTOSEL 5.19 12/22] erofs: avoid the potentially wrong m_plen for big pcluster

From: Sasha Levin
Date: Wed Sep 14 2022 - 05:03:03 EST


From: Yue Hu <huyue2@xxxxxxxxxxx>

[ Upstream commit ea0b7b0d59e81a9c1bc03f8696bb04851bc2ad22 ]

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@xxxxxxxxxxx>
Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220812060150.8510-1-huyue2@xxxxxxxxxxx
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/erofs/zmap.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 572f0b8151ba8..d58549ca1df9b 100644
--- 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,
--
2.35.1