The copy_file_range COPY_FILE_SPLICE capability allows filesystems to
handle cross-superblock copy. However, in the current fuse implementation,
__fuse_copy_file_range accesses src_file->private_data under the assumption
that it points to a fuse_file structure. When the source file belongs to a
non-FUSE filesystem, it will leads to kernel panics.
To resolve this, move the same-superblock check from __fuse_copy_file_range
to fuse_copy_file_range to ensure both files belong to the same fuse
superblock before accessing private_data.
Signed-off-by: Chunsheng Luo <luochunsheng@xxxxxxxx>
---
fs/fuse/file.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 95275a1e2f54..a29f1b84f11b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2984,9 +2984,6 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
if (fc->no_copy_file_range)
return -EOPNOTSUPP;
- if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
- return -EXDEV;
-
inode_lock(inode_in);
err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
inode_unlock(inode_in);
@@ -3066,9 +3063,12 @@ static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
{
ssize_t ret;
+ if (file_inode(src_file)->i_sb != file_inode(dst_file)->i_sb)
+ return splice_copy_file_range(src_file, src_off, dst_file,
+ dst_off, len);
+
ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
len, flags);
-
if (ret == -EOPNOTSUPP || ret == -EXDEV)
ret = splice_copy_file_range(src_file, src_off, dst_file,
dst_off, len);
--
2.43.0
