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* block: fix setting of max_segment_size and seg_boundary maskMilan Broz2008-12-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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/<vg>/<lv> 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 <mbroz@redhat.com> Reviewed-by: Alasdair G Kergon <agk@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Mike Miller <mike.miller@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* dm: avoid destroying table in dm_any_congestedChandra Seetharaman2008-11-131-8/+16
| | | | | | | | | | | | | | | | | | | | | dm_any_congested() just checks for the DMF_BLOCK_IO and has no code to make sure that suspend waits for dm_any_congested() to complete. This patch adds such a check. Without it, a race can occur with dm_table_put() attempting to destroying the table in the wrong thread, the one running dm_any_congested() which is meant to be quick and return immediately. Two examples of problems: 1. Sleeping functions called from congested code, the caller of which holds a spin lock. 2. An ABBA deadlock between pdflush and multipathd. The two locks in contention are inode lock and kernel lock. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: move pending queue wake_up end_io_acctMikulas Patocka2008-11-131-5/+5
| | | | | | | | | | | | This doesn't fix any bug, just moves wake_up immediately after decrementing md->pending, for better code readability. It must be clear to anyone manipulating md->pending to wake up the queue if md->pending reaches zero, so move the wakeup as close to the decrementing as possible. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: warn if args ignoredChandra Seetharaman2008-11-131-0/+4
| | | | | | | | | | | Currently dm ignores the parameters provided to hardware handlers without providing any notifications to the user. This patch just prints a warning message so that the user knows that the arguments are ignored. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: avoid attempting to activate null pathChandra Seetharaman2008-11-131-2/+2
| | | | | | | | | | | Path activation code is called even when the pgpath is NULL. This could lead to a panic in activate_path(). Such a panic is seen in -rt kernel. This problem has been there before the pg_init() was moved to a workqueue. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm stripe: fix init failureHeinz Mauelshagen2008-11-131-1/+3
| | | | | | | Don't proceed if dm_stripe_init() fails to register itself as a dm target. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm raid1: flush workqueue before destructionMikulas Patocka2008-11-131-0/+1
| | | | | | | | | We queue work on keventd queue --- so this queue must be flushed in the destructor. Otherwise, keventd could access mirror_set after it was freed. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* md: linear: Fix a division by zero bug for very small arrays.Andre Noll2008-11-061-0/+2
| | | | | | | | | | | | | | | | | | We currently oops with a divide error on starting a linear software raid array consisting of at least two very small (< 500K) devices. The bug is caused by the calculation of the hash table size which tries to compute sector_div(sz, base) with "base" being zero due to the small size of the component devices of the array. Fix this by requiring the hash spacing to be at least one which implies that also "base" is non-zero. This bug has existed since about 2.6.14. Cc: stable@kernel.org Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: fix bug in raid10 recovery.NeilBrown2008-11-061-1/+1
| | | | | | | | | | | | | | Adding a spare to a raid10 doesn't cause recovery to start. This is due to an silly type in commit 6c2fce2ef6b4821c21b5c42c7207cb9cf8c87eda and so is a bug in 2.6.27 and .28-rc. Thanks to Thomas Backlund for bisecting to find this. Cc: Thomas Backlund <tmb@mandriva.org> Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
* md: revert the recent addition of a call to the BLKRRPART ioctl.NeilBrown2008-11-061-6/+0
| | | | | | | | | | | | | | It turns out that it is only safe to call blkdev_ioctl when the device is actually open (as ->bd_disk is set to NULL on last close). And it is quite possible for do_md_stop to be called when the device is not open. So discard the call to blkdev_ioctl(BLKRRPART) which was added in commit 934d9c23b4c7e31840a895ba4b7e88d6413c81f3 It is just as easy to call this ioctl from userspace when needed (on mdadm -S) so leave it out of the kernel Signed-off-by: NeilBrown <neilb@suse.de>
* Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds2008-10-301-0/+7
|\ | | | | | | | | * 'for-linus' of git://neil.brown.name/md: md: destroy partitions and notify udev when md array is stopped.
| * md: destroy partitions and notify udev when md array is stopped.NeilBrown2008-10-281-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md arrays are not currently destroyed when they are stopped - they remain in /sys/block. Last time I tried this I tripped over locking too much. A consequence of this is that udev doesn't remove anything from /dev. This is rather ugly. As an interim measure until proper device removal can be achieved, make sure all partitions are removed using the BLKRRPART ioctl, and send a KOBJ_CHANGE when an md array is stopped. Signed-off-by: NeilBrown <neilb@suse.de>
* | dm snapshot: wait for chunks in destructorMikulas Patocka2008-10-302-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If there are several snapshots sharing an origin and one is removed while the origin is being written to, the snapshot's mempool may get deleted while elements are still referenced. Prior to dm-snapshot-use-per-device-mempools.patch the pending exceptions may still have been referenced after the snapshot was destroyed, but this was not a problem because the shared mempool was still there. This patch fixes the problem by tracking the number of mempool elements in use. The scenario: - You have an origin and two snapshots 1 and 2. - Someone writes to the origin. - It creates two exceptions in the snapshots, snapshot 1 will be primary exception, snapshot 2's pending_exception->primary_pe will point to the exception in snapshot 1. - The exceptions are being relocated, relocation of exception 1 finishes (but it's pending_exception is still allocated, because it is referenced by an exception from snapshot 2) - The user lvremoves snapshot 1 --- it calls just suspend (does nothing) and destructor. md->pending is zero (there is no I/O submitted to the snapshot by md layer), so it won't help us. - The destructor waits for kcopyd jobs to finish on snapshot 1 --- but there are none. - The destructor on snapshot 1 cleans up everything. - The relocation of exception on snapshot 2 finishes, it drops reference on primary_pe. This frees its primary_pe pointer. Primary_pe points to pending exception created for snapshot 1. So it frees memory into non-existing mempool. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm snapshot: fix register_snapshot deadlockMikulas Patocka2008-10-301-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | register_snapshot() performs a GFP_KERNEL allocation while holding _origins_lock for write, but that could write out dirty pages onto a device that attempts to acquire _origins_lock for read, resulting in deadlock. So move the allocation up before taking the lock. This path is not performance-critical, so it doesn't matter that we allocate memory and free it if we find that we won't need it. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm raid1: fix do_failuresIlpo Jarvinen2008-10-301-1/+2
|/ | | | | | | | | Missing braces. Commit 1f965b1943 (dm raid1: separate region_hash interface part1) broke it. Signed-off-by: Ilpo Jarvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Heinz Mauelshagen <hjm@redhat.com>
* Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds2008-10-261-23/+33
|\ | | | | | | | | | | | | * 'for-linus' of git://neil.brown.name/md: md: allow extended partitions on md devices. md: use sysfs_notify_dirent to notify changes to md/dev-xxx/state md: use sysfs_notify_dirent to notify changes to md/array_state
| * md: allow extended partitions on md devices.NeilBrown2008-10-211-0/+5
| | | | | | | | | | | | | | | | | | | | The new extended partition support provides a much nicer was to have partitions on md devices that the 'mdp' alternate major. We cannot really get rid of 'mdp' at this time, but we can enable extended partitions as that will probably make life easier for sysadmins. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: use sysfs_notify_dirent to notify changes to md/dev-xxx/stateNeilBrown2008-10-211-9/+12
| | | | | | | | | | | | | | | | | | | | The 'state' file for a device reports, for example, when the device has failed. Changes should be reported to userspace ASAP without the possibility of blocking on low-memory. sysfs_notify does have that possibility (as it takes a mutex which can be held across a kmalloc) so use sysfs_notify_dirent instead. Signed-off-by: NeilBrown <neilb@suse.de>
| * md: use sysfs_notify_dirent to notify changes to md/array_stateNeilBrown2008-10-211-14/+16
| | | | | | | | | | | | | | | | | | Now that we have sysfs_notify_dirent, use it to notify changes to md/array_state. As sysfs_notify_dirent can be called in atomic context, we can remove the delayed notify and the MD_NOTIFY_ARRAY_STATE flag. Signed-off-by: NeilBrown <neilb@suse.de>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdevLinus Torvalds2008-10-236-60/+34
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev: (66 commits) [PATCH] kill the rest of struct file propagation in block ioctls [PATCH] get rid of struct file use in blkdev_ioctl() BLKBSZSET [PATCH] get rid of blkdev_locked_ioctl() [PATCH] get rid of blkdev_driver_ioctl() [PATCH] sanitize blkdev_get() and friends [PATCH] remember mode of reiserfs journal [PATCH] propagate mode through swsusp_close() [PATCH] propagate mode through open_bdev_excl/close_bdev_excl [PATCH] pass fmode_t to blkdev_put() [PATCH] kill the unused bsize on the send side of /dev/loop [PATCH] trim file propagation in block/compat_ioctl.c [PATCH] end of methods switch: remove the old ones [PATCH] switch sr [PATCH] switch sd [PATCH] switch ide-scsi [PATCH] switch tape_block [PATCH] switch dcssblk [PATCH] switch dasd [PATCH] switch mtd_blkdevs [PATCH] switch mmc ...
| * | [PATCH] pass fmode_t to blkdev_put()Al Viro2008-10-212-4/+4
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] switch mdAl Viro2008-10-211-10/+10
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] switch dmAl Viro2008-10-211-21/+10
| | | | | | | | | | | | | | | | | | ioctl() doesn't need BKL here Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] beginning of methods conversionAl Viro2008-10-212-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To keep the size of changesets sane we split the switch by drivers; to keep the damn thing bisectable we do the following: 1) rename the affected methods, add ones with correct prototypes, make (few) callers handle both. That's this changeset. 2) for each driver convert to new methods. *ALL* drivers are converted in this series. 3) kill the old (renamed) methods. Note that it _is_ a flagday; all in-tree drivers are converted and by the end of this series no trace of old methods remain. The only reason why we do that this way is to keep the damn thing bisectable and allow per-driver debugging if anything goes wrong. New methods: open(bdev, mode) release(disk, mode) ioctl(bdev, mode, cmd, arg) /* Called without BKL */ compat_ioctl(bdev, mode, cmd, arg) locked_ioctl(bdev, mode, cmd, arg) /* Called with BKL, legacy */ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] introduce __blkdev_driver_ioctl()Al Viro2008-10-212-17/+4
| | | | | | | | | | | | | | | | | | | | | | | | Analog of blkdev_driver_ioctl() with sane arguments. For now uses fake struct file, by the end of the series it won't and blkdev_driver_ioctl() will become a wrapper around it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] lose unused arguments in dm ioctl callbacksAl Viro2008-10-213-5/+3
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | [PATCH] introduce fmode_t, do annotationsAl Viro2008-10-212-8/+8
| |/ | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-linus' of ↵Linus Torvalds2008-10-231-15/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (46 commits) [PATCH] fs: add a sanity check in d_free [PATCH] i_version: remount support [patch] vfs: make security_inode_setattr() calling consistent [patch 1/3] FS_MBCACHE: don't needlessly make it built-in [PATCH] move executable checking into ->permission() [PATCH] fs/dcache.c: update comment of d_validate() [RFC PATCH] touch_mnt_namespace when the mount flags change [PATCH] reiserfs: add missing llseek method [PATCH] fix ->llseek for more directories [PATCH vfs-2.6 6/6] vfs: add LOOKUP_RENAME_TARGET intent [PATCH vfs-2.6 5/6] vfs: remove LOOKUP_PARENT from non LOOKUP_PARENT lookup [PATCH vfs-2.6 4/6] vfs: remove unnecessary fsnotify_d_instantiate() [PATCH vfs-2.6 3/6] vfs: add __d_instantiate() helper [PATCH vfs-2.6 2/6] vfs: add d_ancestor() [PATCH vfs-2.6 1/6] vfs: replace parent == dentry->d_parent by IS_ROOT() [PATCH] get rid of on-stack dentry in udf [PATCH 2/2] anondev: switch to IDA [PATCH 1/2] anondev: init IDR statically [JFFS2] Use d_splice_alias() not d_add() in jffs2_lookup() [PATCH] Optimise NFS readdir hack slightly. ...
| * | [PATCH] dm: kill lookup_device wrapperChristoph Hellwig2008-10-231-15/+6
| |/ | | | | | | | | | | | | | | Now that lookup_bdev is exported and used by dm just use it directly instead of through a trivial wrapper. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | dm: tidy local_initKiyoshi Ueda2008-10-211-17/+17
| | | | | | | | | | | | | | | | | | This patch tidies local_init() in preparation for request-based dm. No functional change. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm: remove unused flush_allKiyoshi Ueda2008-10-211-13/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the DM_WQ_FLUSH_ALL state that is unnecessary. The dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL) in dm_suspend() is never invoked because: - 'goto flush_and_out' is the same as 'goto out' because the 'goto flush_and_out' is called only when '!noflush' - If r is non-zero, then the code above will invoke 'goto out' and skip this code. No functional change. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm raid1: separate region_hash interface part1Heinz Mauelshagen2008-10-213-687/+808
| | | | | | | | | | | | | | | | Separate the region hash code from raid1 so it can be shared by forthcoming targets. Use BUG_ON() for failed async dm_io() calls. Signed-off-by: Heinz Mauelshagen <hjm@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm: mark split bio as clonedMartin K. Petersen2008-10-211-0/+1
| | | | | | | | | | | | | | When a bio gets split, mark its fragments with the BIO_CLONED flag. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm crypt: remove waitqueueMilan Broz2008-10-211-8/+0
| | | | | | | | | | | | | | Remove waitqueue no longer needed with the async crypto interface. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm crypt: fix async splitMilan Broz2008-10-211-1/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When writing io, dm-crypt has to allocate a new cloned bio and encrypt the data into newly-allocated pages attached to this bio. In rare cases, because of hw restrictions (e.g. physical segment limit) or memory pressure, sometimes more than one cloned bio has to be used, each processing a different fragment of the original. Currently there is one waitqueue which waits for one fragment to finish and continues processing the next fragment. But when using asynchronous crypto this doesn't work, because several fragments may be processed asynchronously or in parallel and there is only one crypt context that cannot be shared between the bio fragments. The result may be corruption of the data contained in the encrypted bio. The patch fixes this by allocating new dm_crypt_io structs (with new crypto contexts) and running them independently. The fragments contains a pointer to the base dm_crypt_io struct to handle reference counting, so the base one is properly deallocated after all the fragments are finished. In a low memory situation, this only uses one additional object from the mempool. If the mempool is empty, the next allocation simple waits for previous fragments to complete. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm crypt: tidy sectorMilan Broz2008-10-211-2/+5
| | | | | | | | | | | | | | | | | | | | Prepare local sector variable (offset) for later patch. Do not update io->sector for still-running I/O. No functional change. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm: remove dm header from targetsMikulas Patocka2008-10-2114-13/+18
| | | | | | | | | | | | | | | | Change #include "dm.h" to #include <linux/device-mapper.h> in all targets. Targets should not need direct access to internal DM structures. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm: publish array_too_bigMikulas Patocka2008-10-213-14/+2
| | | | | | | | | | | | | | | | | | | | | | | | Move array_too_big to include/linux/device-mapper.h because it is used by targets. Remove the test from dm-raid1 as the number of mirror legs is limited such that it can never fail. (Even for stripes it seems rather unlikely.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm exception store: fix misordered writesMikulas Patocka2008-10-211-3/+8
| | | | | | | | | | | | | | | | | | | | We must zero the next chunk on disk *before* writing out the current chunk, not after. Otherwise if the machine crashes at the wrong time, the "end of metadata" marker may be missing. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* | dm exception store: refactor zero_areaAlasdair G Kergon2008-10-211-34/+68
| | | | | | | | | | | | | | | | | | | | | | | | Use a separate buffer for writing zeroes to the on-disk snapshot exception store, make the updating of ps->current_area explicit and refactor the code in preparation for the fix in the next patch. No functional change. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@kernel.org
* | dm snapshot: drop unused last_percentMikulas Patocka2008-10-212-4/+0
| | | | | | | | | | | | | | | | The last_percent field is unused - remove it. (It dates from when events were triggered as each X% filled up.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* | dm snapshot: fix primary_pe raceMikulas Patocka2008-10-211-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix a race condition with primary_pe ref_count handling. put_pending_exception runs under dm_snapshot->lock, it does atomic_dec_and_test on primary_pe->ref_count, and later does atomic_read primary_pe->ref_count. __origin_write does atomic_dec_and_test on primary_pe->ref_count without holding dm_snapshot->lock. This opens the following race condition: Assume two CPUs, CPU1 is executing put_pending_exception (and holding dm_snapshot->lock). CPU2 is executing __origin_write in parallel. primary_pe->ref_count == 2. CPU1: if (primary_pe && atomic_dec_and_test(&primary_pe->ref_count)) origin_bios = bio_list_get(&primary_pe->origin_bios); ... decrements primary_pe->ref_count to 1. Doesn't load origin_bios CPU2: if (first && atomic_dec_and_test(&primary_pe->ref_count)) { flush_bios(bio_list_get(&primary_pe->origin_bios)); free_pending_exception(primary_pe); /* If we got here, pe_queue is necessarily empty. */ return r; } ... decrements primary_pe->ref_count to 0, submits pending bios, frees primary_pe. CPU1: if (!primary_pe || primary_pe != pe) free_pending_exception(pe); ... this has no effect. if (primary_pe && !atomic_read(&primary_pe->ref_count)) free_pending_exception(primary_pe); ... sees ref_count == 0 (written by CPU 2), does double free !! This bug can happen only if someone is simultaneously writing to both the origin and the snapshot. If someone is writing only to the origin, __origin_write will submit kcopyd request after it decrements primary_pe->ref_count (so it can't happen that the finished copy races with primary_pe->ref_count decrementation). If someone is writing only to the snapshot, __origin_write isn't invoked at all and the race can't happen. The race happens when someone writes to the snapshot --- this creates pending_exception with primary_pe == NULL and starts copying. Then, someone writes to the same chunk in the snapshot, and __origin_write races with termination of already submitted request in pending_complete (that calls put_pending_exception). This race may be reason for bugs: http://bugzilla.kernel.org/show_bug.cgi?id=11636 https://bugzilla.redhat.com/show_bug.cgi?id=465825 The patch fixes the code to make sure that: 1. If atomic_dec_and_test(&primary_pe->ref_count) returns false, the process must no longer dereference primary_pe (because someone else may free it under us). 2. If atomic_dec_and_test(&primary_pe->ref_count) returns true, the process is responsible for freeing primary_pe. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* | dm kcopyd: avoid queue shuffleKazuo Ito2008-10-211-1/+12
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Write throughput to LVM snapshot origin volume is an order of magnitude slower than those to LV without snapshots or snapshot target volumes, especially in the case of sequential writes with O_SYNC on. The following patch originally written by Kevin Jamieson and Jan Blunck and slightly modified for the current RCs by myself tries to improve the performance by modifying the behaviour of kcopyd, so that it pushes back an I/O job to the head of the job queue instead of the tail as process_jobs() currently does when it has to wait for free pages. This way, write requests aren't shuffled to cause extra seeks. I tested the patch against 2.6.27-rc5 and got the following results. The test is a dd command writing to snapshot origin followed by fsync to the file just created/updated. A couple of filesystem benchmarks gave me similar results in case of sequential writes, while random writes didn't suffer much. dd if=/dev/zero of=<somewhere on snapshot origin> bs=4096 count=... [conv=notrunc when updating] 1) linux 2.6.27-rc5 without the patch, write to snapshot origin, average throughput (MB/s) 10M 100M 1000M create,dd 511.46 610.72 11.81 create,dd+fsync 7.10 6.77 8.13 update,dd 431.63 917.41 12.75 update,dd+fsync 7.79 7.43 8.12 compared with write throughput to LV without any snapshots, all dd+fsync and 1000 MiB writes perform very poorly. 10M 100M 1000M create,dd 555.03 608.98 123.29 create,dd+fsync 114.27 72.78 76.65 update,dd 152.34 1267.27 124.04 update,dd+fsync 130.56 77.81 77.84 2) linux 2.6.27-rc5 with the patch, write to snapshot origin, average throughput (MB/s) 10M 100M 1000M create,dd 537.06 589.44 46.21 create,dd+fsync 31.63 29.19 29.23 update,dd 487.59 897.65 37.76 update,dd+fsync 34.12 30.07 26.85 Although still not on par with plain LV performance - cannot be avoided because it's copy on write anyway - this simple patch successfully improves throughtput of dd+fsync while not affecting the rest. Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Kazuo Ito <ito.kazuo@oss.ntt.co.jp> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2008-10-172-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (39 commits) [SCSI] sd: fix compile failure with CONFIG_BLK_DEV_INTEGRITY=n libiscsi: fix locking in iscsi_eh_device_reset libiscsi: check reason why we are stopping iscsi session to determine error value [SCSI] iscsi_tcp: return a descriptive error value during connection errors [SCSI] libiscsi: rename host reset to target reset [SCSI] iscsi class: fix endpoint id handling [SCSI] libiscsi: Support drivers initiating session removal [SCSI] libiscsi: fix data corruption when target has to resend data-in packets [SCSI] sd: Switch kernel printing level for DIF messages [SCSI] sd: Correctly handle all combinations of DIF and DIX [SCSI] sd: Always print actual protection_type [SCSI] sd: Issue correct protection operation [SCSI] scsi_error: fix target reset handling [SCSI] lpfc 8.2.8 v2 : Add statistical reporting control and additional fc vendor events [SCSI] lpfc 8.2.8 v2 : Add sysfs control of target queue depth handling [SCSI] lpfc 8.2.8 v2 : Revert target busy in favor of transport disrupted [SCSI] scsi_dh_alua: remove REQ_NOMERGE [SCSI] lpfc 8.2.8 : update driver version to 8.2.8 [SCSI] lpfc 8.2.8 : Add MSI-X support [SCSI] lpfc 8.2.8 : Update driver to use new Host byte error code DID_TRANSPORT_DISRUPTED ...
| * [SCSI] block: separate failfast into multiple bits.Mike Christie2008-10-132-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multipath is best at handling transport errors. If it gets a device error then there is not much the multipath layer can do. It will just access the same device but from a different path. This patch breaks up failfast into device, transport and driver errors. The multipath layers (md and dm mutlipath) only ask the lower levels to fast fail transport errors. The user of failfast, read ahead, will ask to fast fail on all errors. Note that blk_noretry_request will return true if any failfast bit is set. This allows drivers that do not support the multipath failfast bits to continue to fail on any failfast error like before. Drivers like scsi that are able to fail fast specific errors can check for the specific fail fast type. In the next patch I will convert scsi. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* | Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds2008-10-169-174/+114
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://neil.brown.name/md: md: fix input truncation in safe_delay_store() md: check for memory allocation failure in faulty personality md: build failure due to missing delay.h md: Relax minimum size restrictions on chunk_size. md: remove space after function name in declaration and call. md: Remove unnecessary #includes, #defines, and function declarations. md: Convert remaining 1k representations in linear.c to sectors. md: linear.c: Make two local variables sector-based. md: linear: Represent dev_info->size and dev_info->offset in sectors. md: linear.c: Remove broken debug code. md: linear.c: Remove pointless initialization of curr_offset. md: linear.c: Fix typo in comment. md: Don't try to set an array to 'read-auto' if it is already in that state. md: Allow metadata_version to be updated for externally managed metadata. md: Fix rdev_size_store with size == 0
| * | md: fix input truncation in safe_delay_store()Dan Williams2008-10-161-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | safe_delay_store() currently truncates the last character of input since it tells strlcpy that the buffer can only hold 'len' characters, off by one. sysfs already null terminates the buffer, so just increase the last argument to strlcpy. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: check for memory allocation failure in faulty personalitySven Wegener2008-10-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | It's a fault injection module, but I don't think we should oops here. Signed-off-by: Sven Wegener <sven.wegener@stealer.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Neil Brown <neilb@suse.de>
| * | md: build failure due to missing delay.hStephen Rothwell2008-10-153-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today's linux-next build (powerpc ppc64_defconfig) failed like this: drivers/md/raid1.c: In function 'sync_request': drivers/md/raid1.c:1759: error: implicit declaration of function 'msleep_interruptible' make[3]: *** [drivers/md/raid1.o] Error 1 make[3]: *** Waiting for unfinished jobs.... drivers/md/raid10.c: In function 'sync_request': drivers/md/raid10.c:1749: error: implicit declaration of function 'msleep_interruptible' make[3]: *** [drivers/md/raid10.o] Error 1 drivers/md/md.c: In function 'md_do_sync': drivers/md/md.c:5915: error: implicit declaration of function 'msleep' Caused by commit 6caa3b0bbdb474647f6bdd8a958ffc46f78d8d58 ("md: Remove unnecessary #includes, #defines, and function declarations"). I added the following patch. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NeilBrown <neilb@suse.de>
| * | md: Relax minimum size restrictions on chunk_size.NeilBrown2008-10-133-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the 'chunk_size' of an array must be at-least PAGE_SIZE. This makes moving an array to a machine with a larger PAGE_SIZE, or changing the kernel to use a larger PAGE_SIZE, can stop an array from working. For RAID10 and RAID4/5/6, this is non-trivial to fix as the resync process works on whole pages at a time, and assumes them to be wholly within a stripe. For other raid personalities, this restriction is not needed at all and can be dropped. So remove the test on chunk_size from common can, and add it in just the places where it is needed: raid10 and raid4/5/6. Signed-off-by: NeilBrown <neilb@suse.de>
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