Some anon_bdev filesystems (e.g. overlayfs, ceph) don't have s_blocksize
set. Returning zero from FIGETBSZ ioctl results in a Floating point
exception from the e2fsprogs utility filefrag, which divides the size of
the file with the value returned by FIGETBSZ.
Fix the interface by returning -EINVAL for these filesystems.
Fixes: d1d04ef8572b ("ovl: stack file ops")
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/ioctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 2005529af560..0400297c8d72 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -669,6 +669,9 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
return ioctl_fiemap(filp, arg);
case FIGETBSZ:
+ /* anon_bdev filesystems may not have a block size */
+ if (!inode->i_sb->s_blocksize)
+ return -EINVAL;
return put_user(inode->i_sb->s_blocksize, argp);
case FICLONE:
--
2.17.1
