linux/block, branch v2.6.28

Enforce a minimum SG_IO timeout

2008-12-05T22:49:18Z

There's no point in having too short SG_IO timeouts, since if the command does end up timing out, we'll end up through the reset sequence that is several seconds long in order to abort the command that timed out. As a result, shorter timeouts than a few seconds simply do not make sense, as the recovery would be longer than the timeout itself. Add a BLK_MIN_SG_TIMEOUT to match the existign BLK_DEFAULT_SG_TIMEOUT. Suggested-by: Alan Cox Acked-by: Tejun Heo Acked-by: Jens Axboe Cc: Jeff Garzik Signed-off-by: Linus Torvalds

[PATCH 1/2] kill FMODE_NDELAY_NOW

2008-12-04T09:22:57Z

Update FMODE_NDELAY before each ioctl call so that we can kill the magic FMODE_NDELAY_NOW. It would be even better to do this directly in setfl(), but for that we'd need to have FMODE_NDELAY for all files, not just block special files. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

[PATCH] Fix block dev compat ioctl handling

2008-12-04T09:22:55Z

Commit 33c2dca4957bd0da3e1af7b96d0758d97e708ef6 (trim file propagation in block/compat_ioctl.c) removed the handling of some ioctls from compat_blkdev_driver_ioctl. That caused them to be rejected as unknown by the compat layer. Signed-off-by: Andreas Schwab Cc: Al Viro Signed-off-by: Al Viro

block: fix setting of max_segment_size and seg_boundary mask

2008-12-03T11:55:55Z

Fix setting of max_segment_size and seg_boundary mask for stacked md/dm devices. When stacking devices (LVM over MD over SCSI) some of the request queue parameters are not set up correctly in some cases by default, namely max_segment_size and and seg_boundary mask. If you create MD device over SCSI, these attributes are zeroed. Problem become when there is over this mapping next device-mapper mapping - queue attributes are set in DM this way: request_queue max_segment_size seg_boundary_mask SCSI 65536 0xffffffff MD RAID1 0 0 LVM 65536 -1 (64bit) Unfortunately bio_add_page (resp. bio_phys_segments) calculates number of physical segments according to these parameters. During the generic_make_request() is segment cout recalculated and can increase bio->bi_phys_segments count over the allowed limit. (After bio_clone() in stack operation.) Thi is specially problem in CCISS driver, where it produce OOPS here BUG_ON(creq->nr_phys_segments > MAXSGENTRIES); (MAXSEGENTRIES is 31 by default.) Sometimes even this command is enough to cause oops: dd iflag=direct if=/dev// of=/dev/null bs=128000 count=10 This command generates bios with 250 sectors, allocated in 32 4k-pages (last page uses only 1024 bytes). For LVM layer, it allocates bio with 31 segments (still OK for CCISS), unfortunatelly on lower layer it is recalculated to 32 segments and this violates CCISS restriction and triggers BUG_ON(). The patch tries to fix it by: * initializing attributes above in queue request constructor blk_queue_make_request() * make sure that blk_queue_stack_limits() inherits setting (DM uses its own function to set the limits because it blk_queue_stack_limits() was introduced later. It should probably switch to use generic stack limit function too.) * sets the default seg_boundary value in one place (blkdev.h) * use this mask as default in DM (instead of -1, which differs in 64bit) Bugs related to this: https://bugzilla.redhat.com/show_bug.cgi?id=471639 http://bugzilla.kernel.org/show_bug.cgi?id=8672 Signed-off-by: Milan Broz Reviewed-by: Alasdair G Kergon Cc: Neil Brown Cc: FUJITA Tomonori Cc: Tejun Heo Cc: Mike Miller Signed-off-by: Jens Axboe

block: internal dequeue shouldn't start timer

2008-12-03T11:41:26Z

blkdev_dequeue_request() and elv_dequeue_request() are equivalent and both start the timeout timer. Barrier code dequeues the original barrier request but doesn't passes the request itself to lower level driver, only broken down proxy requests; however, as the original barrier code goes through the same dequeue path and timeout timer is started on it. If barrier sequence takes long enough, this timer expires but the low level driver has no idea about this request and oops follows. Timeout timer shouldn't have been started on the original barrier request as it never goes through actual IO. This patch unexports elv_dequeue_request(), which has no external user anyway, and makes it operate on elevator proper w/o adding the timer and make blkdev_dequeue_request() call elv_dequeue_request() and add timer. Internal users which don't pass the request to driver - barrier code and end_that_request_last() - are converted to use elv_dequeue_request(). Signed-off-by: Tejun Heo Cc: Mike Anderson Signed-off-by: Jens Axboe

block: set disk->node_id before it's being used

2008-12-03T11:41:20Z

disk->node_id will be refered in allocating in disk_expand_part_tbl, so we should set it before disk->node_id is refered. Signed-off-by: Cheng Renquan Signed-off-by: Jens Axboe

When block layer fails to map iov, it calls bio_unmap_user to undo

2008-12-03T11:41:20Z

mapping. Which is good if pages were mapped - but if they were provided by someone else and just copied then bad things happen - pages are released once here, and once by caller, leading to user triggerable BUG at include/linux/mm.h:246. Signed-off-by: Petr Vandrovec Signed-off-by: Jens Axboe

block: hold extra reference to bio in blk_rq_map_user_iov()

2008-11-18T14:08:56Z

If the size passed in is OK but we end up mapping too many segments, we call the unmap path directly like from IO completion. But from IO completion we have an extra reference to the bio, so this error case goes OOPS when it attempts to free and already free bio. Fix it by getting an extra reference to the bio before calling the unmap failure case. Reported-by: Petr Vandrovec Signed-off-by: Jens Axboe

block: fix boot failure with CONFIG_DEBUG_BLOCK_EXT_DEVT=y and nash

2008-11-18T14:08:56Z

We run into system boot failure with kernel 2.6.28-rc. We found it on a couple of machines, including T61 notebook, nehalem machine, and another HPC NX6325 notebook. All the machines use FedoraCore 8 or FedoraCore 9. With kernel prior to 2.6.28-rc, system boot doesn't fail. I debug it and locate the root cause. Pls. see http://bugzilla.kernel.org/show_bug.cgi?id=11899 https://bugzilla.redhat.com/show_bug.cgi?id=471517 As a matter of fact, there are 2 bugs. 1)root=/dev/sda1, system boot randomly fails. Mostly, boot for 5 times and fails once. nash has a bug. Some of its functions misuse return value 0. Sometimes, 0 means timeout and no uevent available. Sometimes, 0 means nash gets an uevent, but the uevent isn't block-related (for exmaple, usb). If by coincidence, kernel tells nash that uevents are available, but kernel also set timeout, nash might stops collecting other uevents in queue if current uevent isn't block-related. I work out a patch for nash to fix it. http://bugzilla.kernel.org/attachment.cgi?id=18858 2) root=LABEL=/, system always can't boot. initrd init reports switchroot fails. Here is an executation branch of nash when booting: (1) nash read /sys/block/sda/dev; Assume major is 8 (on my desktop) (2) nash query /proc/devices with the major number; It found line "8 sd"; (3) nash use 'sd' to search its own probe table to find device (DISK) type for the device and add it to its own list; (4) Later on, it probes all devices in its list to get filesystem labels; scsi register "8 sd" always. When major is 259, nash fails to find the device(DISK) type. I enables CONFIG_DEBUG_BLOCK_EXT_DEVT=y when compiling kernel, so 259 is picked up for device /dev/sda1, which causes nash to fail to find device (DISK) type. To fixing issue 2), I create a patch for nash and another patch for kernel. http://bugzilla.kernel.org/attachment.cgi?id=18859 http://bugzilla.kernel.org/attachment.cgi?id=18837 Below is the patch for kernel 2.6.28-rc4. It registers blkext, a new block device in proc/devices. With 2 patches on nash and 1 patch on kernel, I boot my machines for dozens of times without failure. Signed-off-by Zhang Yanmin Acked-by: Tejun Heo Signed-off-by: Jens Axboe

block: make add_partition() return pointer to hd_struct

2008-11-18T14:08:56Z

Make add_partition() return pointer to the new hd_struct on success and ERR_PTR() value on failure. This change will be used to fix md autodetection bug. Signed-off-by: Tejun Heo Cc: Neil Brown Signed-off-by: Jens Axboe