On 2025/5/7 17:40, Hongbo Li wrote:
EROFS uses NID to indicate the on-disk inode offset, which can
exceed 32 bits. However, the default encode_fh uses the ino32,
thus it doesn't work if the image is larger than 128GiB.
Let's introduce our own helpers to encode file handles.
It's easy to reproduce:
1. prepare an erofs image with nid bigger than U32_MAX
2. mount -t erofs foo.img /mnt/erofs
3. set exportfs with configuration: /mnt/erofs *(rw,sync,
no_root_squash)
4. mount -t nfs $IP:/mnt/erofs /mnt/nfs
5. md5sum /mnt/nfs/foo # foo is the file which nid bigger
than U32_MAX. # you will get ESTALE error.
In the case of overlayfs, the underlying filesystem's file
handle is encoded in ovl_fb.fid, which is similar to NFS's
case. If the NID of file is larger than U32_MAX, the overlay
will get -ESTALE error when calls exportfs_decode_fh.
Fixes: 3e917cc305c6 ("erofs: make filesystem exportable")
Signed-off-by: Hongbo Li <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Thanks,
Gao Xiang
