vfs: fix FIGETBSZ ioctl on an overlayfs file

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: d1d04ef857 ("ovl: stack file ops")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2018-10-11 17:38:14 +03:00 коммит произвёл Miklos Szeredi
Родитель 1f244dc521
Коммит 8f97d1e991
1 изменённых файлов: 3 добавлений и 0 удалений

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@ -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: