user/sven/linux.git/drivers/md, branch v3.10.97

Revert "dm mpath: fix stalls when handling invalid ioctls"

2016-02-19T22:22:38Z

commit 47796938c46b943d157ac8a6f9ed4e3b98b83cf4 upstream. This reverts commit a1989b330093578ea5470bea0a00f940c444c466. That commit introduced a regression at least for the case of the SG_IO ioctl() running without CAP_SYS_RAWIO capability (e.g., unprivileged users) when there are no active paths: the ioctl() fails with the ENOTTY errno immediately rather than blocking due to queue_if_no_path until a path becomes active, for example. That case happens to be exercised by QEMU KVM guests with 'scsi-block' devices (qemu "-device scsi-block" [1], libvirt "" [2]) from multipath devices; which leads to SCSI/filesystem errors in such a guest. More general scenarios can hit that regression too. The following demonstration employs a SG_IO ioctl() with a standard SCSI INQUIRY command for this objective (some output & user changes omitted for brevity and comments added for clarity). Reverting that commit restores normal operation (queueing) in failing scenarios; tested on linux-next (next-20151022). 1) Test-case is based on sg_simple0 [3] (just SG_IO; remove SG_GET_VERSION_NUM) $ cat sg_simple0.c ... see [3] ... $ sed '/SG_GET_VERSION_NUM/,/}/d' sg_simple0.c > sgio_inquiry.c $ gcc sgio_inquiry.c -o sgio_inquiry 2) The ioctl() works fine with active paths present. # multipath -l 85ag56 85ag56 (...) dm-19 IBM ,2145 size=60G features='1 queue_if_no_path' hwhandler='0' wp=rw |-+- policy='service-time 0' prio=0 status=active | |- 8:0:11:0 sdz 65:144 active undef running | `- 9:0:9:0 sdbf 67:144 active undef running `-+- policy='service-time 0' prio=0 status=enabled |- 8:0:12:0 sdae 65:224 active undef running `- 9:0:12:0 sdbo 68:32 active undef running $ ./sgio_inquiry /dev/mapper/85ag56 Some of the INQUIRY command's response: IBM 2145 0000 INQUIRY duration=0 millisecs, resid=0 3) The ioctl() fails with ENOTTY errno with _no_ active paths present, for unprivileged users (rather than blocking due to queue_if_no_path). # for path in $(multipath -l 85ag56 | grep -o 'sd[a-z]\+'); \ do multipathd -k"fail path $path"; done # multipath -l 85ag56 85ag56 (...) dm-19 IBM ,2145 size=60G features='1 queue_if_no_path' hwhandler='0' wp=rw |-+- policy='service-time 0' prio=0 status=enabled | |- 8:0:11:0 sdz 65:144 failed undef running | `- 9:0:9:0 sdbf 67:144 failed undef running `-+- policy='service-time 0' prio=0 status=enabled |- 8:0:12:0 sdae 65:224 failed undef running `- 9:0:12:0 sdbo 68:32 failed undef running $ ./sgio_inquiry /dev/mapper/85ag56 sg_simple0: Inquiry SG_IO ioctl error: Inappropriate ioctl for device 4) dmesg shows that scsi_verify_blk_ioctl() failed for SG_IO (0x2285); it returns -ENOIOCTLCMD, later replaced with -ENOTTY in vfs_ioctl(). $ dmesg <...> [] device-mapper: multipath: Failing path 65:144. [] device-mapper: multipath: Failing path 67:144. [] device-mapper: multipath: Failing path 65:224. [] device-mapper: multipath: Failing path 68:32. [] sgio_inquiry: sending ioctl 2285 to a partition! 5) The ioctl() only works if the SYS_CAP_RAWIO capability is present (then queueing happens -- in this example, queue_if_no_path is set); this is due to a conditional check in scsi_verify_blk_ioctl(). # capsh --drop=cap_sys_rawio -- -c './sgio_inquiry /dev/mapper/85ag56' sg_simple0: Inquiry SG_IO ioctl error: Inappropriate ioctl for device # ./sgio_inquiry /dev/mapper/85ag56 & [1] 72830 # cat /proc/72830/stack [] 0xc00000171c0df700 [] __switch_to+0x204/0x350 [] msleep+0x5c/0x80 [] dm_blk_ioctl+0x70/0x170 [] blkdev_ioctl+0x2b0/0x9b0 [] block_ioctl+0x64/0xd0 [] do_vfs_ioctl+0x490/0x780 [] SyS_ioctl+0xd4/0xf0 [] system_call+0x38/0xd0 6) This is the function call chain exercised in this analysis: SYSCALL_DEFINE3(ioctl, <...>) @ fs/ioctl.c -> do_vfs_ioctl() -> vfs_ioctl() ... error = filp->f_op->unlocked_ioctl(filp, cmd, arg); ... -> dm_blk_ioctl() @ drivers/md/dm.c -> multipath_ioctl() @ drivers/md/dm-mpath.c ... (bdev = NULL, due to no active paths) ... if (!bdev || <...>) { int err = scsi_verify_blk_ioctl(NULL, cmd); if (err) r = err; } ... -> scsi_verify_blk_ioctl() @ block/scsi_ioctl.c ... if (bd && bd == bd->bd_contains) // not taken (bd = NULL) return 0; ... if (capable(CAP_SYS_RAWIO)) // not taken (unprivileged user) return 0; ... printk_ratelimited(KERN_WARNING "%s: sending ioctl %x to a partition!\n" <...>); return -ENOIOCTLCMD; <- ... return r ? : <...> <- ... if (error == -ENOIOCTLCMD) error = -ENOTTY; out: return error; ... Links: [1] http://git.qemu.org/?p=qemu.git;a=commit;h=336a6915bc7089fb20fea4ba99972ad9a97c5f52 [2] https://libvirt.org/formatdomain.html#elementsDisks (see 'disk' -> 'device') [3] http://tldp.org/HOWTO/SCSI-Generic-HOWTO/pexample.html (Revision 1.2, 2002-05-03) Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm btree: fix leak of bufio-backed block in btree_split_sibling error path

2016-02-19T22:22:37Z

commit 30ce6e1cc5a0f781d60227e9096c86e188d2c2bd upstream. The block allocated at the start of btree_split_sibling() is never released if later insert_at() fails. Fix this by releasing the previously allocated bufio block using unlock_block(). Reported-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

md/raid10: submit_bio_wait() returns 0 on success

2015-11-09T18:12:59Z

commit 681ab4696062f5aa939c9e04d058732306a97176 upstream. This was introduced with 9e882242c6193ae6f416f2d8d8db0d9126bd996b which changed the return value of submit_bio_wait() to return != 0 on error, but didn't update the caller accordingly. Fixes: 9e882242c6 ("block: Add submit_bio_wait(), remove from md") Reported-by: Bill Kuzeja Signed-off-by: Jes Sorensen Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

md/raid1: submit_bio_wait() returns 0 on success

2015-11-09T18:12:59Z

commit 203d27b0226a05202438ddb39ef0ef1acb14a759 upstream. This was introduced with 9e882242c6193ae6f416f2d8d8db0d9126bd996b which changed the return value of submit_bio_wait() to return != 0 on error, but didn't update the caller accordingly. Fixes: 9e882242c6 ("block: Add submit_bio_wait(), remove from md") Reported-by: Bill Kuzeja Signed-off-by: Jes Sorensen Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

dm btree: fix leak of bufio-backed block in btree_split_beneath error path

2015-11-09T18:12:58Z

commit 4dcb8b57df3593dcb20481d9d6cf79d1dc1534be upstream. btree_split_beneath()'s error path had an outstanding FIXME that speaks directly to the potential for _not_ cleaning up a previously allocated bufio-backed block. Fix this by releasing the previously allocated bufio block using unlock_block(). Reported-by: Mikulas Patocka Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Signed-off-by: Greg Kroah-Hartman

dm btree remove: fix a bug when rebalancing nodes after removal

2015-11-09T18:12:58Z

commit 2871c69e025e8bc507651d5a9cf81a8a7da9d24b upstream. Commit 4c7e309340ff ("dm btree remove: fix bug in redistribute3") wasn't a complete fix for redistribute3(). The redistribute3 function takes 3 btree nodes and shares out the entries evenly between them. If the three nodes in total contained (MAX_ENTRIES * 3) - 1 entries between them then this was erroneously getting rebalanced as (MAX_ENTRIES - 1) on the left and right, and (MAX_ENTRIES + 1) in the center. Fix this issue by being more careful about calculating the target number of entries for the left and right nodes. Unit tested in userspace using this program: https://github.com/jthornber/redistribute3-test/blob/master/redistribute3_t.c Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin: fix missing pool reference count decrement in pool_ctr error path

2015-10-27T00:44:50Z

commit ba30670f4d5292c4e7f7980bbd5071f7c4794cdd upstream. Fixes: ac8c3f3df ("dm thin: generate event when metadata threshold passed") Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm cache: fix NULL pointer when switching from cleaner policy

2015-10-22T21:37:53Z

commit 2bffa1503c5c06192eb1459180fac4416575a966 upstream. The cleaner policy doesn't make use of the per cache block hint space in the metadata (unlike the other policies). When switching from the cleaner policy to mq or smq a NULL pointer crash (in dm_tm_new_block) was observed. The crash was caused by bugs in dm-cache-metadata.c when trying to skip creation of the hint btree. The minimal fix is to change hint size for the cleaner policy to 4 bytes (only hint size supported). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

md: flush ->event_work before stopping array.

2015-10-22T21:37:52Z

commit ee5d004fd0591536a061451eba2b187092e9127c upstream. The 'event_work' worker used by dm-raid may still be running when the array is stopped. This can result in an oops. So flush the workqueue on which it is run after detaching and before destroying the device. Reported-by: Heinz Mauelshagen Signed-off-by: NeilBrown Fixes: 9d09e663d550 ("dm: raid456 basic support") Signed-off-by: Greg Kroah-Hartman

dm raid: fix round up of default region size

2015-10-22T21:37:50Z

commit 042745ee53a0a7c1f5aff191a4a24213c6dcfb52 upstream. Commit 3a0f9aaee028 ("dm raid: round region_size to power of two") intended to make sure that the default region size is a power of two. However, the logic in that commit is incorrect and sets the variable region_size to 0 or 1, depending on whether min_region_size is a power of two. Fix this logic, using roundup_pow_of_two(), so that region_size is properly rounded up to the next power of two. Signed-off-by: Mikulas Patocka Fixes: 3a0f9aaee028 ("dm raid: round region_size to power of two") Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman