Restrict short block cloning requests

If we are copying only one block and it is smaller than recordsize property, do not allow destination to grow beyond one block if it is not there yet. Otherwise the destination will get stuck with that block size forever, that can be as small as 512 bytes, no matter how big the destination grow later. Reviewed-by: Kay Pedersen <[email protected]> Reviewed-by: Rob Norris <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15321
openzfsonwindows · Dec 11, 2023 · 175680f · 175680f
1 parent 9e750ad
commit 175680f
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
@@ -1221,6 +1221,19 @@ zfs_clone_range(znode_t *inzp, uint64_t *inoffp, znode_t *outzp,
 		goto unlock;
 	}
 
+	/*
+	 * If we are copying only one block and it is smaller than recordsize
+	 * property, do not allow destination to grow beyond one block if it
+	 * is not there yet.  Otherwise the destination will get stuck with
+	 * that block size forever, that can be as small as 512 bytes, no
+	 * matter how big the destination grow later.
+	 */
+	if (len <= inblksz && inblksz < outzfsvfs->z_max_blksz &&
+	    outzp->z_size <= inblksz && outoff + len > inblksz) {
+		error = SET_ERROR(EINVAL);
+		goto unlock;
+	}
+
 	error = zn_rlimit_fsize(outoff + len);
 	if (error != 0) {
 		goto unlock;