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authorLuis Henriques <lhenriques@suse.com>2019-10-31 11:49:39 +0000
committerIlya Dryomov <idryomov@gmail.com>2019-11-05 15:42:58 +0100
commita3a0819388b2bf15e7eafe38ff6aacfc27b12df0 (patch)
tree16e134b5e219b5d17bfae211d92a16ca269b2e23 /fs/ceph
parent5bb5e6ee6f5c557dcd19822eccd7bcced1e1a410 (diff)
downloadlinux-a3a0819388b2bf15e7eafe38ff6aacfc27b12df0.tar.bz2
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 <lhenriques@suse.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/file.c12
1 files changed, 10 insertions, 2 deletions
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 */