From a3a0819388b2bf15e7eafe38ff6aacfc27b12df0 Mon Sep 17 00:00:00 2001 From: Luis Henriques Date: Thu, 31 Oct 2019 11:49:39 +0000 Subject: ceph: don't allow copy_file_range when stripe_count != 1 copy_file_range tries to use the OSD 'copy-from' operation, which simply performs a full object copy. Unfortunately, the implementation of this system call assumes that stripe_count is always set to 1 and doesn't take into account that the data may be striped across an object set. If the file layout has stripe_count different from 1, then the destination file data will be corrupted. For example: Consider a 8 MiB file with 4 MiB object size, stripe_count of 2 and stripe_size of 2 MiB; the first half of the file will be filled with 'A's and the second half will be filled with 'B's: 0 4M 8M Obj1 Obj2 +------+------+ +----+ +----+ file: | AAAA | BBBB | | AA | | AA | +------+------+ |----| |----| | BB | | BB | +----+ +----+ If we copy_file_range this file into a new file (which needs to have the same file layout!), then it will start by copying the object starting at file offset 0 (Obj1). And then it will copy the object starting at file offset 4M -- which is Obj1 again. Unfortunately, the solution for this is to not allow remote object copies to be performed when the file layout stripe_count is not 1 and simply fallback to the default (VFS) copy_file_range implementation. Cc: stable@vger.kernel.org Signed-off-by: Luis Henriques Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov --- fs/ceph/file.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/ceph/file.c b/fs/ceph/file.c index d2854cd2f4f5..bd77adb64bfd 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -1959,10 +1959,18 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off, if (ceph_test_mount_opt(src_fsc, NOCOPYFROM)) return -EOPNOTSUPP; + /* + * Striped file layouts require that we copy partial objects, but the + * OSD copy-from operation only supports full-object copies. Limit + * this to non-striped file layouts for now. + */ if ((src_ci->i_layout.stripe_unit != dst_ci->i_layout.stripe_unit) || - (src_ci->i_layout.stripe_count != dst_ci->i_layout.stripe_count) || - (src_ci->i_layout.object_size != dst_ci->i_layout.object_size)) + (src_ci->i_layout.stripe_count != 1) || + (dst_ci->i_layout.stripe_count != 1) || + (src_ci->i_layout.object_size != dst_ci->i_layout.object_size)) { + dout("Invalid src/dst files layout\n"); return -EOPNOTSUPP; + } if (len < src_ci->i_layout.object_size) return -EOPNOTSUPP; /* no remote copy will be done */ -- cgit v1.2.3-59-g8ed1b