- 12 Jun, 2012 1 commit
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Lars Ellenberg authored
BUG: unable to handle kernel NULL pointer dereference at (null) ... [<d1e17561>] ? _drbd_bm_set_bits+0x151/0x240 [drbd] [<d1e236f8>] ? receive_bitmap+0x4f8/0xbc0 [drbd] This fixes an off-by-one error in the receive_bitmap() path, if run-length encoded bitmap transfer is enabled. If the bitmap is an exact multiple of PAGE_SIZE, which means the visible capacity of the drbd device is an exact multiple of 128 MiB (for 4k page size), and bitmap compression (use-rle) is enabled (which became default with 8.4), and the very last bit is dirty and reported in an rle comressed bitmap packet, we ended up trying to kmap_atomic a page pointer that does not exist (bitmap->bm_pages[last index + 1]). bug introduced by: Date: Fri Jul 24 15:33:24 2009 +0200 set bits: optimize for complete last word, fix off-by-one-word corner case made effective by: Date: Thu Dec 16 00:32:38 2010 +0100 drbd: get rid of unused debug code Long time ago, we had paranoia code in the bitmap that allocated one extra word, assigned a magic value, and checked on every occasion that the magic value was still unchanged. That debug code is unused, the extra long word complicates code a bit. Get rid of it. No-one triggered this bug in the last few years, because a large subset of our userbase is unaffected: * typically the last few blocks of a device are not modified frequently, and remain unset * use-rle was disabled by default in drbd < 8.4 * those with slightly "odd" device sizes, or * drbd internal meta data (which will skew the device size slightly, thus makes it harder to have a bug relevant device size) Signed-off-by:Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by:
Lars Ellenberg <lars.ellenberg@linbit.com>
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- 18 May, 2012 5 commits
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git://git.drbd.org/linux-drbdJens Axboe authored
Philipp writes: This are the updates we have in the drbd-8.3 tree. They are intended for your "for-3.5/drivers" drivers branch. These changes include one new feature: * Allow detach from frozen backing devices with the new --force option; configurable timeout for backing devices by the new disk-timeout option And huge number of bug fixes: * Fixed a write ordering problem on SyncTarget nodes for a write to a block that gets resynced at the same time. The bug can only be triggered with a device that has a firmware that actually reorders writes to the same block * Fixed a race between disconnect and receive_state, that could cause a IO lockup * Fixed resend/resubmit for requests with disk or network timeout * Make sure that hard state changed do not disturb the connection establishing process (I.e. detach due to an IO error). When the bug was triggered it caused a retry in the connect process * Postpone soft state changes to no disturb the connection establishing process (I.e. becoming primary). When the bug was triggered it could cause both nodes going into SyncSource state * Fixed a refcount leak that could cause failures when trying to unload a protocol family modules, that was used by DRBD * Dedicated page pool for meta data IOs * Deny normal detach (as opposed to --forced) if the user tries to detach from the last UpToDate disk in the resource * Fixed a possible protocol error that could be caused by "unusual" BIOs. * Enforce the disk-timeout option also on meta-data IO operations * Implemented stable bitmap pages when we do a full write out of the bitmap * Fixed a rare compatibility issue with DRBD's older than 8.3.7 when negotiating the bio_size * Fixed a rare race condition where an empty resync could stall with if pause/unpause events happen in parallel * Made the re-establishing of connections quicker, if it got a broken pipe once. Previously there was a bug in the code caused it to waste the first successful established connection after a broken pipe event. PS: I am postponing the drbd-8.4 for mainline for one or two kernel development cycles more (the ~400 patchets set). -
Jens Axboe authored
Merge branch 'stable/for-jens-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-3.5/drivers Konrad writes: Please git pull the following branch: git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/for-jens-3.5 in your for-3.5/drivers branch. The changes in it are rather simple - cleaning up some code and adding proper mechanism to unload without leaking memory.
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Jiri Kosina authored
I have fought the current maintainer to the death in the Thunderdome [1] https://lkml.org/lkml/2012/5/16/370 Umm, actually, there is noone taking care of the driver due to lack of real hardware, and I still have some. The driver exposes bugs on emulated/virtualized devices (mostly due to timing), but it's essential to verify the fixes against a real hardware as well (which has been holding back some of the fixes). Acked-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Jiri Kosina <jkosina@suse.cz>
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Jiri Kosina authored
Block layer now handles O_EXCL in a generic way for block devices. The semantics is however different for floppy and all other block devices, as floppy driver contains its own O_EXCL handling. The semantics for all-but-floppy bdevs is "there can be at most one O_EXCL open of this file", while for floppy bdev the semantics is "if someone has the bdev open with O_EXCL, noone else can open it". There is actual userspace-observable change in behavior because of this since commit e525fd89 ("block: make blkdev_get/put() handle exclusive access") -- on kernels containing this commit, mount of /dev/fd0 causes the fd0 block device be claimed with _EXCL, preventing subsequent open(/dev/fd0). Bring things back into shape, i.e. make it possible, analogically to other block devices, to mount the floppy and open() it afterwards -- remove the floppy-specific handling and let the generic bdev code O_EXCL handling take over. Signed-off-by:
Tejun Heo <tj@kernel.org> Acked-by:
NeilBrown <neilb@suse.de> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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Jiri Kosina authored
There are several races in floppy driver between bottom half (scheduled_work) and timers (fd_timeout, fd_timer). Due to slowness of the actual floppy devices, those races are never (at least to my knowledge) triggered on a bare floppy metal. However on virtualized (emulated) floppy drives, which are of course magnitudes faster than the real ones, these races trigger reliably. They usually exhibit themselves as NULL pointer dereferences during DMA setup, such as BUG: unable to handle kernel NULL pointer dereference at 0000000a [ ... snip ... ] EIP: 0060:[<c02053d5>] EFLAGS: 00010293 CPU: 0 EAX: ffffe000 EBX: 0000000a ECX: 00000000 EDX: 0000000a ESI: c05d2718 EDI: 00000000 EBP: 00000000 ESP: f540fe44 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 0, ti=f540e000 task=c082d5a0 task.ti=c0826000) Stack: ffffe000 00001ffc 00000000 00000000 00000000 c05d2718 c0708b40 f540fe80 c020470f c05d2718 c0708b40 00000000 f540fe80 0000000a f540fee4 00000000 c0708b40 f540fee4 00000000 00000000 c020526b 00000000 c05d2718 c0708b40 Call Trace: [<c020470f>] dump_trace+0xaf/0x110 [<c020526b>] show_trace_log_lvl+0x4b/0x60 [<c0205298>] show_trace+0x18/0x20 [<c05c5811>] dump_stack+0x6d/0x72 [<c0248527>] warn_slowpath_common+0x77/0xb0 [<c02485f3>] warn_slowpath_fmt+0x33/0x40 [<f7ec593c>] setup_DMA+0x14c/0x210 [floppy] [<f7ecaa95>] setup_rw_floppy+0x105/0x190 [floppy] [<c0256d08>] run_timer_softirq+0x168/0x2a0 [<c024e762>] __do_softirq+0xc2/0x1c0 [<c02042ed>] do_softirq+0x7d/0xb0 [<f54d8a00>] 0xf54d89ff but other instances can be easily seen as well. This can be observed at least under VMWare, VirtualBox and KVM. This patch converts all the timers and bottom halfs to be processed in a single workqueue. This aproach has been already discussed back in 2010 if I remember correctly, and Acked by Linus [1], but it then never made it to the tree. This all is based on original idea and code of Stephen Hemminger. I have ported original Stepen's code to the current state of the floppy driver, and performed quite some testing (on real hardware), which didn't reveal any issues (this includes not only writing and reading data, but also formatting (unfortunately I didn't find any Double-Density disks any more)). Ability to handle errors properly (supplying known bad floppies) has also been verified. [1] http://kerneltrap.org/mailarchive/linux-kernel/2010/6/11/4582092Based-on-patch-by:
Stephen Hemminger <shemminger@vyatta.com> Acked-by:
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- 11 May, 2012 2 commits
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Jan Beulich authored
The blkdev major must be released upon exit, or else the module can't attach to devices using the same majors upon being loaded again. Also avoid leaking the minor tracking bitmap. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Signed-off-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Jan Beulich authored
- devices beyond xvdzz didn't get proper names assigned at all - extended devices with minors not representable within the kernel's major/minor bit split spilled into foreign majors Signed-off-by:
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- 10 May, 2012 2 commits
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Lars Ellenberg authored
Signed-off-by:
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Cong Wang authored
THIS_MODULE is NULL only when drbd is compiled as built-in, so the #ifdef CONFIG_MODULES should be #ifdef MODULE instead. This fixes the warning: drivers/block/drbd/drbd_main.c: In function ‘drbd_buildtag’: drivers/block/drbd/drbd_main.c:4187:24: warning: the comparison will always evaluate as ‘true’ for the address of ‘__this_module’ will never be NULL [-Waddress] Signed-off-by:
WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by:
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- 09 May, 2012 30 commits
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Philipp Reisner authored
It got lost with the commit 5a7bbad2 "block: remove support for bio remapping from ->make_request" Signed-off-by:
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Lars Ellenberg authored
Don't rely on availability of bios from the global fs_bio_set, we should use our own bio_set for meta data IO. Signed-off-by:
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Lars Ellenberg authored
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Arne Redlich authored
If bm_page_async_io is advised to use a new page for I/O (BM_AIO_COPY_PAGES is set), it will get it from a mempool. Once the mempool has to dip into its reserves the page is not reinitialized, i.e. page->private contains garbage, which will lead to various problems once the I/O completes (dereferences of NULL pointers, the submitting thread getting stuck in D-state, ...). Signed-off-by:
Arne Redlich <arne.redlich@googlemail.com> Signed-off-by:
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Lars Ellenberg authored
Conflicts: drbd/drbd_bitmap.c Signed-off-by:
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Lars Ellenberg authored
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Lars Ellenberg authored
Symptom: messages similar to "FIXME asender in bm_change_bits_to, bitmap locked for 'write from resync_finished' by worker" If a resync or verify is finished (or aborted), a full bitmap writeout is triggered. If we have ongoing local IO, the bitmap may still change during that writeout, pending and not yet processed acks may cause bits to be cleared, while new writes may cause bits to be to be set. To fix this, introduce the drbd_bm_write_copy_pages() variant. Signed-off-by:
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Lars Ellenberg authored
When a resync or online verify is finished or aborted, drbd does a bulk write-out of changed bitmap pages. If *in that very moment* a new verify or resync is triggered, this can race: ASSERT( !test_bit(BITMAP_IO, &mdev->flags) ) in drbd_main.c FIXME going to queue 'set_n_write from StartingSync' but 'write from resync_finished' still pending? and similar. This can be observed with e.g. tight invalidate loops in test scripts, and probably has no real-life implication. Still, that race can be solved by first quiescen the device, before starting a new resync or verify. Signed-off-by:
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Lars Ellenberg authored
DRBD can freeze IO, due to fencing policy (fencing resource-and-stonith), or because we lost access to data (on-no-data-accessible suspend-io). Resuming from there (re-connect, or re-attach, or explicit admin intervention) should "just work". Unfortunately, if the re-attach/re-connect did not happen within the timeout, since the commit drbd: Implemented real timeout checking for request processing time if so configured, the request_timer_fn() would timeout and detach/disconnect virtually immediately. This change tracks the most recent attach and connect, and does not timeout within <configured timeout interval> after attach/connect. Signed-off-by:
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Philipp Reisner authored
This could be exploited by a peer which runs modified code. Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Philipp Reisner authored
Changes to the role and disk state should be delayed or rejected while we establish a connection. This is necessary, since the peer will base its resync decision on the UUIDs and the state we sent in the drbd_connect() function. The most prominent example for this race is becoming primary after sending state and UUIDs and before the state changes to C_WF_CONNECTION. Signed-off-by:
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Lars Ellenberg authored
One invocation in the endio handler is good enough, we don't need mention it for each of the different ways it calls __req_mod(). Signed-off-by:
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Lars Ellenberg authored
Just because this request happened during a resync does not mean it may pretend to have been barrier-acked. Signed-off-by:
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Lars Ellenberg authored
READ_RETRY_REMOTE_CANCELED needs to be grouped with the other _CANCELED cases, not with CONNECTION_LOST_WHILE_PENDING, as that would complete (fail) the bio even if the device became suspended. Signed-off-by:
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Lars Ellenberg authored
OOS_HANDED_TO_NETWORK should not be grouped with the various *_CANCELED/*_FAILED cases. Also, not only clear the RQ_NET_QUEUED flag, but also mark it RQ_NET_DONE, so it can be distinguished from a local-only request even after that. Signed-off-by:
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Lars Ellenberg authored
We used to have a barrier implementation where barrier_nr 0 was reserved. That is long gone. Just use the full sequence space. Signed-off-by:
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Lars Ellenberg authored
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Lars Ellenberg authored
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Lars Ellenberg authored
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Lars Ellenberg authored
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Lars Ellenberg authored
We assumed only bios with bi_idx == 0 would end up in drbd_make_request(). That is wrong. At least device mapper, in __clone_and_map(), may submit clones only covering a partial bio, but sharing the original bvec, by adjusting bi_idx and relevant other bio members of the clone. We used __bio_for_each_segment() in various places, even though that is documented as * drivers should not use the __ version unless they _really_ want to * run through the entire bio and not just pending pieces Impact: we would send the full bio bvec, even for the clone with bi_idx > 0, which will cause data corruption on the peer (because we submit wrong data at the clone offset), and will cause a DRBD protocol error, disconnect/reconnect and resync (thus fixing the corruption), because the next package header would be expected right in the middle of the sent data, causing DRBD magic mismatch. Fix: drop the assert, and use bio_for_each_segment() instead of the __ version. Conflicts: drbd/drbd_tracing.c Signed-off-by:
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Philipp Reisner authored
If a SyncTarget node gets a P_RS_DATA_REPLY before a P_DATA packet for the same sector, it simply submits these two IO requests. This is be possible because on the SyncSource node, the data of the P_RS_DATA_REPLY packet was read from disk. Immediately after that a write request from upper layers came in. The disk scheduler or even the "hardware" queues on the disk drive might reorder these writes. Signed-off-by:
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Philipp Reisner authored
When we have a write request and a state change C_WF_BITMAP_S -> C_SYNC_SOURCE at the same time, and it happens that the line remote = remote && drbd_should_do_remote(s); stills sees C_WF_BITMAP_S, and send_oos = rw == WRITE && drbd_should_send_oos(s); already sees C_SYNC_SOURCE both are 0. This causes the write to not be mirrored, but marked as out-of-sync on the Sync_Source node. Signed-off-by:
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Lars Ellenberg authored
Without this, iostat frequently sees bogus svctime and >= 100% "utilization". Signed-off-by:
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Lars Ellenberg authored
drbd_accept was modelled after kernel_accept with drbd commit 53eb779 in July 2008. Only, kernel_accept was then broken, and only fixed later with kernel commit 1b08534e in Dec 2008: net: Fix module refcount leak in kernel_accept() Impact: protocol families provided as modules, e.g. ipv6 or ib_sdp, would soon have their reference count become negative, preventing them from being unloaded (likely), or worse, hit zero without actually being unused, allowing them to be unloaded while still in use (unlikely, but if triggered, causing a kernel crash). Signed-off-by:
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Philipp Reisner authored
If the backing device is already frozen during attach, we failed to recognize that. The current disk-timeout code works on top of the drbd_request objects. During attach we do not allow IO and therefore never generate a drbd_request object but block before that in drbd_make_request(). This patch adds the timeout to all drbd_md_sync_page_io(). Before this patch we used to go from D_ATTACHING directly to D_DISKLESS if IO failed during attach. We can no longer do this since we have to stay in D_FAILED until all IO ops issued to the backing device returned. Signed-off-by:
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Philipp Reisner authored
I.e. in C_WF_REPORT_PARAMS or in C_WF_CONNECTION. Sending may already work in these cstates, but the peer still expects the HandShake / ConnectionFeatures packet. Actually triggered by the Testuite on kugel. Signed-off-by:
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Lars Ellenberg authored
If the asender thread, or request_timer_fn(), or some other part of the code, decided to drop the connection (because of timeout or other), but the receiver just now was processing a P_STATE packet, there was a chance that receive_state() would do a hard state change "re-establishing" an already failed connection without additional handshake. Log excerpt: Remote failed to finish a request within ko-count * timeout peer( Secondary -> Unknown ) conn( Connected -> Timeout ) pdsk( UpToDate -> DUnknown ) asender terminated ... peer( Unknown -> Secondary ) conn( Timeout -> Connected ) pdsk( DUnknown -> UpToDate ) peer_isp( 0 -> 1 ) ... Connection closed peer( Secondary -> Unknown ) conn( Connected -> Unconnected ) pdsk( UpToDate -> DUnknown ) peer_isp( 1 -> 0 ) receiver terminated Impact: while the connection state is erroneously "Connected", requests may be queued and even sent, which would never be acknowledged, and may have been missed by the cleanup. These requests would never be completed. The next drbd_suspend_io() will then lock up, waiting forever for these requests to complete. Fixed in several code paths: Make sure the connection state is NetworkFailure or worse before starting the cleanup in drbd_disconnect(). This should make sure the cleanup won't miss any requests. Disallow receive_state() to "upgrade" the connection state from an error state. This will make sure the "illegal" state transition won't happen. For all connection failure states, relax the safe-guard in sanitize_state() again to silently mask out those state changes (e.g. Timeout -> Connected becomes Timeout -> Timeout). Signed-off-by:
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Lars Ellenberg authored
drbd_try_clear_on_disk_bm() has a sanity check for the number of blocks left to be resynced (rs_left) in the current resync extent. If it detects a mismatch, it complains, and forces a disconnect using drbd_force_state(mdev, NS(conn, C_DISCONNECTING)); Unfortunately, this may be called while holding the req_lock, and drbd_force_state() want's to aquire that lock itself. Deadlock. Don't force a disconnect, but fix up rs_left by recounting and reassigning the number of dirty blocks in that extent. Signed-off-by:
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Philipp Reisner authored
This bug might have caused troubles if disk-barriers and the ahead-behind more are enabled at the same time. Signed-off-by:
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