Re: [syzbot] [iomap?] [erofs?] WARNING in iomap_iter (5)

From: Edward Adam Davis
Date: Sun Jun 15 2025 - 00:05:21 EST


#syz test

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 14ea47f954f5..664611cca689 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -686,7 +686,17 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
vi->z_tailextent_headlcn = 0;
goto done;
}
+
vi->z_advise = le16_to_cpu(h->h_advise);
+ if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
+ vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+ Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+ erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto out_put_metabuf;
+ }
+
vi->z_lclusterbits = sb->s_blocksize_bits + (h->h_clusterbits & 15);
if (vi->datalayout == EROFS_INODE_COMPRESSED_FULL &&
(vi->z_advise & Z_EROFS_ADVISE_EXTENTS)) {
@@ -711,14 +721,6 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
goto out_put_metabuf;
}

- if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
- vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
- Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
- erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
- vi->nid);
- err = -EFSCORRUPTED;
- goto out_put_metabuf;
- }
if (vi->datalayout == EROFS_INODE_COMPRESSED_COMPACT &&
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {