The dm-stripe target currently does not enforce that the size of a stripe device be a multiple of the chunk-size. Under certain conditions, this can lead to I/O requests going off the end of an underlying device. This test-case shows one example. echo "0 100 linear /dev/hdb1 0" | dmsetup create linear0 echo "0 100 linear /dev/hdb1 100" | dmsetup create linear1 echo "0 200 striped 2 32 /dev/mapper/linear0 0 /dev/mapper/linear1 0" | \ dmsetup create stripe0 dd if=/dev/zero of=/dev/mapper/stripe0 bs=1k This will produce the output: dd: writing '/dev/mapper/stripe0': Input/output error 97+0 records in 96+0 records out And in the kernel log will be: attempt to access beyond end of device dm-0: rw=0, want=104, limit=100 The patch will check that the table size is a multiple of the stripe chunk-size when the table is created, which will prevent the above striped device from being created. This should not affect tools like LVM or EVMS, since in all the cases I can think of, striped devices are always created with the sizes being a multiple of the chunk-size. The size of a stripe device must be a multiple of its chunk-size. (akpm: that typecast is quite gratuitous)
Unified · Split
| @@ -103,9 +103,15 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) · 102 unmodified lines | |||
| 103 | return -EINVAL; | 103 | return -EINVAL; |
| 104 | } | 104 | } |
| 105 | 105 | ||
| 106 | if (((uint32_t)ti->len) & (chunk_size - 1)) { | ||
| 107 | ti->error = "dm-stripe: Target length not divisible by " | ||
| 108 | "chunk size"; | ||
| 109 | return -EINVAL; | ||
| 110 | } | ||
| 111 | |||
| 106 | width = ti->len; | 112 | width = ti->len; |
| 107 | if (sector_div(width, stripes)) { | 113 | if (sector_div(width, stripes)) { |
| 108 | ti->error = "dm-stripe: Target length not divisable by " | 114 | ti->error = "dm-stripe: Target length not divisible by " |
| 109 | "number of stripes"; | 115 | "number of stripes"; |
| 110 | return -EINVAL; | 116 | return -EINVAL; |
| 111 | } | 117 | } |