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| author | Ilya Dryomov <ilya.dryomov@inktank.com> | 2013-12-16 21:26:32 +0400 |
|---|---|---|
| committer | Ilya Dryomov <ilya.dryomov@inktank.com> | 2013-12-31 22:32:04 +0400 |
| commit | 7e513d43669a0505ee3b122344176147a674bcbf (patch) | |
| tree | b1c8b984589b20699d7432082bdc1d742d2c76ba /drivers/block | |
| parent | 183028052b48db2b34c09fd54f0bc465eaa305eb (diff) | |
| download | linux-7e513d43669a0505ee3b122344176147a674bcbf.tar.xz | |
rbd: enable extended devt in single-major mode
If single-major device number allocation scheme is turned on, instead
of reserving 256 minors per device, which imposes a limit of 4096
images mapped at once, reserve 16 minors per device and enable extended
devt feature. This results in a theoretical limit of 65536 images
mapped at once, and still allows to have more than 15 partititions:
partitions starting with 16th are mapped under major 259 (Block
Extended Major):
$ rbd showmapped
id pool image snap device
0 rbd b5 - /dev/rbd0 # no partitions
1 rbd b2 - /dev/rbd1 # 40 partitions
2 rbd b3 - /dev/rbd2 # 2 partitions
$ cat /proc/partitions
251 0 1024 rbd0
251 16 1024 rbd1
251 17 0 rbd1p1
251 18 0 rbd1p2
...
251 30 0 rbd1p14
251 31 0 rbd1p15
259 0 0 rbd1p16
259 1 0 rbd1p17
...
259 23 0 rbd1p39
259 24 0 rbd1p40
251 32 1024 rbd2
251 33 0 rbd2p1
251 34 0 rbd2p2
(major 251 was assigned dynamically at module load time)
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/rbd.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index e5ddcb58e9a2..11ae4c1238a6 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -91,7 +91,8 @@ static int atomic_dec_return_safe(atomic_t *v) #define RBD_DRV_NAME "rbd" -#define RBD_PART_SHIFT 8 +#define RBD_MINORS_PER_MAJOR 256 +#define RBD_SINGLE_MAJOR_PART_SHIFT 4 #define RBD_SNAP_DEV_NAME_PREFIX "snap_" #define RBD_MAX_SNAP_NAME_LEN \ @@ -415,12 +416,12 @@ static void rbd_spec_put(struct rbd_spec *spec); static int rbd_dev_id_to_minor(int dev_id) { - return dev_id << RBD_PART_SHIFT; + return dev_id << RBD_SINGLE_MAJOR_PART_SHIFT; } static int minor_to_rbd_dev_id(int minor) { - return minor >> RBD_PART_SHIFT; + return minor >> RBD_SINGLE_MAJOR_PART_SHIFT; } static BUS_ATTR(add, S_IWUSR, NULL, rbd_add); @@ -3434,7 +3435,9 @@ static int rbd_init_disk(struct rbd_device *rbd_dev) u64 segment_size; /* create gendisk info */ - disk = alloc_disk(1 << RBD_PART_SHIFT); + disk = alloc_disk(single_major ? + (1 << RBD_SINGLE_MAJOR_PART_SHIFT) : + RBD_MINORS_PER_MAJOR); if (!disk) return -ENOMEM; @@ -3442,6 +3445,8 @@ static int rbd_init_disk(struct rbd_device *rbd_dev) rbd_dev->dev_id); disk->major = rbd_dev->major; disk->first_minor = rbd_dev->minor; + if (single_major) + disk->flags |= GENHD_FL_EXT_DEVT; disk->fops = &rbd_bd_ops; disk->private_data = rbd_dev; |