summaryrefslogtreecommitdiff
path: root/drivers/block/xen-blkback
AgeCommit message (Collapse)Author
2014-02-11xen-blkback: init persistent_purge_work work_structRoger Pau Monne
Initialize persistent_purge_work work_struct on xen_blkif_alloc (and remove the previous initialization done in purge_persistent_gnt). This prevents flush_work from complaining even if purge_persistent_gnt has not been used. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10Merge branch 'stable/for-jens-3.14' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip into for-linus Konrad writes: Please git pull the following branch: git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git stable/for-jens-3.14 which is based off v3.13-rc6. If you would like me to rebase it on a different branch/tag I would be more than happy to do so. The patches are all bug-fixes and hopefully can go in 3.14. They deal with xen-blkback shutdown and cause memory leaks as well as shutdown races. They should go to stable tree and if you are OK with I will ask them to backport those fixes. There is also a fix to xen-blkfront to deal with unexpected state transition. And lastly a fix to the header where it was using the __aligned__ unnecessarily.
2014-02-07xen-blkif: drop struct blkif_request_segment_alignedRoger Pau Monne
This was wrongly introduced in commit 402b27f9, the only difference between blkif_request_segment_aligned and blkif_request_segment is that the former has a named padding, while both share the same memory layout. Also correct a few minor glitches in the description, including for it to no longer assume PAGE_SIZE == 4096. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> [Description fix by Jan Beulich] Signed-off-by: Jan Beulich <jbeulich@suse.com> Reported-by: Jan Beulich <jbeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2014-02-07xen-blkback: fix shutdown raceRoger Pau Monne
Introduce a new variable to keep track of the number of in-flight requests. We need to make sure that when xen_blkif_put is called the request has already been freed and we can safely free xen_blkif, which was not the case before. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Reviewed-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2014-02-07xen-blkback: fix memory leaksRoger Pau Monne
I've at least identified two possible memory leaks in blkback, both related to the shutdown path of a VBD: - blkback doesn't wait for any pending purge work to finish before cleaning the list of free_pages. The purge work will call put_free_pages and thus we might end up with pages being added to the free_pages list after we have emptied it. Fix this by making sure there's no pending purge work before exiting xen_blkif_schedule, and moving the free_page cleanup code to xen_blkif_free. - blkback doesn't wait for pending requests to end before cleaning persistent grants and the list of free_pages. Again this can add pages to the free_pages list or persistent grants to the persistent_gnts red-black tree. Fixed by moving the persistent grants and free_pages cleanup code to xen_blkif_free. Also, add some checks in xen_blkif_free to make sure we are cleaning everything. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Matt Rushton <mrushton@amazon.com> Reviewed-by: Matt Rushton <mrushton@amazon.com> Cc: Matt Wilson <msw@amazon.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2014-02-07xen-blkback: fix memory leak when persistent grants are usedMatt Rushton
Currently shrink_free_pagepool() is called before the pages used for persistent grants are released via free_persistent_gnts(). This results in a memory leak when a VBD that uses persistent grants is torn down. Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xen.org Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: Matt Rushton <mrushton@amazon.com> Signed-off-by: Matt Wilson <msw@amazon.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-11-23block: Abstract out bvec iteratorKent Overstreet
Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-11-08xen/blkback: fix reference countingVegard Nossum
If the permission check fails, we drop a reference to the blkif without having taken it in the first place. The bug was introduced in commit 604c499cbbcc3d5fe5fb8d53306aa0fae1990109 (xen/blkback: Check device permissions before allowing OP_DISCARD). Cc: stable@vger.kernel.org Cc: Jan Beulich <JBeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-09-11block: replace strict_strtoul() with kstrtoul()Jingoo Han
The use of strict_strtoul() is not preferred, because strict_strtoul() is obsolete. Thus, kstrtoul() should be used. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-22Merge branch 'for-3.11/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block IO driver bits from Jens Axboe: "As I mentioned in the core block pull request, due to real life circumstances the driver pull request would be late. Now it looks like -rc2 late... On the plus side, apart form the rsxx update, these are all things that I could argue could go in later in the cycle as they are fixes and not features. So even though things are late, it's not ALL bad. The pull request contains: - Updates to bcache, all bug fixes, from Kent. - A pile of drbd bug fixes (no big features this time!). - xen blk front/back fixes. - rsxx driver updates, some of them deferred form 3.10. So should be well cooked by now" * 'for-3.11/drivers' of git://git.kernel.dk/linux-block: (63 commits) bcache: Allocation kthread fixes bcache: Fix GC_SECTORS_USED() calculation bcache: Journal replay fix bcache: Shutdown fix bcache: Fix a sysfs splat on shutdown bcache: Advertise that flushes are supported bcache: check for allocation failures bcache: Fix a dumb race bcache: Use standard utility code bcache: Update email address bcache: Delete fuzz tester bcache: Document shrinker reserve better bcache: FUA fixes drbd: Allow online change of al-stripes and al-stripe-size drbd: Constants should be UPPERCASE drbd: Ignore the exit code of a fence-peer handler if it returns too late drbd: Fix rcu_read_lock balance on error path drbd: fix error return code in drbd_init() drbd: Do not sleep inside rcu bcache: Refresh usage docs ...
2013-07-03drivers: avoid parsing names as kthread_run() format stringsKees Cook
Calling kthread_run with a single name parameter causes it to be handled as a format string. Many callers are passing potentially dynamic string content, so use "%s" in those cases to avoid any potential accidents. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-25xen-blkback: check the number of iovecs before allocating a biosRoger Pau Monne
With the introduction of indirect segments we can receive requests with a number of segments bigger than the maximum number of allowed iovecs in a bios, so make sure that blkback doesn't try to allocate a bios with more iovecs than BIO_MAX_PAGES Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-06-21xen-blkback: workaround compiler bug in gcc 4.1Roger Pau Monne
The code generat with gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-54) creates an unbound loop for the second foreach_grant_safe loop in purge_persistent_gnt. The workaround is to avoid having this second loop and instead perform all the work inside the first loop by adding a new variable, clean_used, that will be set when all the desired persistent grants have been removed and we need to iterate over the remaining ones to remove the WAS_ACTIVE flag. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-by: Tom O'Neill <toneill@vmem.com> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-06-17xen/blkback: Check for insane amounts of request on the ring (v6).Konrad Rzeszutek Wilk
Check that the ring does not have an insane amount of requests (more than there could fit on the ring). If we detect this case we will stop processing the requests and wait until the XenBus disconnects the ring. The existing check RING_REQUEST_CONS_OVERFLOW which checks for how many responses we have created in the past (rsp_prod_pvt) vs requests consumed (req_cons) and whether said difference is greater or equal to the size of the ring, does not catch this case. Wha the condition does check if there is a need to process more as we still have a backlog of responses to finish. Note that both of those values (rsp_prod_pvt and req_cons) are not exposed on the shared ring. To understand this problem a mini crash course in ring protocol response/request updates is in place. There are four entries: req_prod and rsp_prod; req_event and rsp_event to track the ring entries. We are only concerned about the first two - which set the tone of this bug. The req_prod is a value incremented by frontend for each request put on the ring. Conversely the rsp_prod is a value incremented by the backend for each response put on the ring (rsp_prod gets set by rsp_prod_pvt when pushing the responses on the ring). Both values can wrap and are modulo the size of the ring (in block case that is 32). Please see RING_GET_REQUEST and RING_GET_RESPONSE for the more details. The culprit here is that if the difference between the req_prod and req_cons is greater than the ring size we have a problem. Fortunately for us, the '__do_block_io_op' loop: rc = blk_rings->common.req_cons; rp = blk_rings->common.sring->req_prod; while (rc != rp) { .. blk_rings->common.req_cons = ++rc; /* before make_response() */ } will loop up to the point when rc == rp. The macros inside of the loop (RING_GET_REQUEST) is smart and is indexing based on the modulo of the ring size. If the frontend has provided a bogus req_prod value we will loop until the 'rc == rp' - which means we could be processing already processed requests (or responses) often. The reason the RING_REQUEST_CONS_OVERFLOW is not helping here is b/c it only tracks how many responses we have internally produced and whether we would should process more. The astute reader will notice that the macro RING_REQUEST_CONS_OVERFLOW provides two arguments - more on this later. For example, if we were to enter this function with these values: blk_rings->common.sring->req_prod = X+31415 (X is the value from the last time __do_block_io_op was called). blk_rings->common.req_cons = X blk_rings->common.rsp_prod_pvt = X The RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, blk_rings->common.req_cons) is doing: req_cons - rsp_prod_pvt >= 32 Which is, X - X >= 32 or 0 >= 32 And that is false, so we continue on looping (this bug). If we re-use said macro RING_REQUEST_CONS_OVERFLOW and pass in the rp instead (sring->req_prod) of rc, the this macro can do the check: req_prod - rsp_prov_pvt >= 32 Which is, X + 31415 - X >= 32 , or 31415 >= 32 which is true, so we can error out and break out of the function. Unfortunatly the difference between rsp_prov_pvt and req_prod can be at 32 (which would error out in the macro). This condition exists when the backend is lagging behind with the responses and still has not finished responding to all of them (so make_response has not been called), and the rsp_prov_pvt + 32 == req_cons. This ends up with us not being able to use said macro. Hence introducing a new macro called RING_REQUEST_PROD_OVERFLOW which does a simple check of: req_prod - rsp_prod_pvt > RING_SIZE And with the X values from above: X + 31415 - X > 32 Returns true. Also not that if the ring is full (which is where the RING_REQUEST_CONS_OVERFLOW triggered), we would not hit the same condition: X + 32 - X > 32 Which is false. Lets use that macro. Note that in v5 of this patchset the macro was different - we used an earlier version. Cc: stable@vger.kernel.org [v1: Move the check outside the loop] [v2: Add a pr_warn as suggested by David] [v3: Use RING_REQUEST_CONS_OVERFLOW as suggested by Jan] [v4: Move wake_up after kthread_stop as suggested by Jan] [v5: Use RING_REQUEST_PROD_OVERFLOW instead] [v6: Use RING_REQUEST_PROD_OVERFLOW - Jan's version] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> gadsa
2013-06-07xen/blkback: Check device permissions before allowing OP_DISCARDKonrad Rzeszutek Wilk
We need to make sure that the device is not RO or that the request is not past the number of sectors we want to issue the DISCARD operation for. This fixes CVE-2013-2140. Cc: stable@vger.kernel.org Acked-by: Jan Beulich <JBeulich@suse.com> Acked-by: Ian Campbell <Ian.Campbell@citrix.com> [v1: Made it pr_warn instead of pr_debug] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-06-07xen/blkback: Use physical sector size for setupStefan Bader
Currently xen-blkback passes the logical sector size over xenbus and xen-blkfront sets up the paravirt disk with that logical block size. But newer drives usually have the logical sector size set to 512 for compatibility reasons and would show the actual sector size only in physical sector size. This results in the device being partitioned and accessed in dom0 with the correct sector size, but the guest thinks 512 bytes is the correct block size. And that results in poor performance. To fix this, blkback gets modified to pass also physical-sector-size over xenbus and blkfront to use both values to set up the paravirt disk. I did not just change the passed in sector-size because I am not sure having a bigger logical sector size than the physical one is valid (and that would happen if a newer dom0 kernel hits an older domU kernel). Also this way a domU set up before should still be accessible (just some tools might detect the unaligned setup). [v2: Make xenbus write failure non-fatal] [v3: Use xenbus_scanf instead of xenbus_gather] [v4: Rebased against segment changes] Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-05-07xen-blkback: allocate list of pending reqs in small chunksRoger Pau Monne
Allocate pending requests in smaller chunks instead of allocating them all at the same time. This change also removes the global array of pending_reqs, it is no longer necessay. Variables related to the grant mapping have been grouped into a struct called "grant_page", this allows to allocate them in smaller chunks, and also improves memory locality. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-block: implement indirect descriptorsRoger Pau Monne
Indirect descriptors introduce a new block operation (BLKIF_OP_INDIRECT) that passes grant references instead of segments in the request. This grant references are filled with arrays of blkif_request_segment_aligned, this way we can send more segments in a request. The proposed implementation sets the maximum number of indirect grefs (frames filled with blkif_request_segment_aligned) to 256 in the backend and 32 in the frontend. The value in the frontend has been chosen experimentally, and the backend value has been set to a sane value that allows expanding the maximum number of indirect descriptors in the frontend if needed. The migration code has changed from the previous implementation, in which we simply remapped the segments on the shared ring. Now the maximum number of segments allowed in a request can change depending on the backend, so we have to requeue all the requests in the ring and in the queue and split the bios in them if they are bigger than the new maximum number of segments. [v2: Fixed minor comments by Konrad. [v1: Added padding to make the indirect request 64bit aligned. Added some BUGs, comments; fixed number of indirect pages in blkif_get_x86_{32/64}_req. Added description about the indirect operation in blkif.h] Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> [v3: Fixed spaces and tabs mix ups] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: expand map/unmap functionsRoger Pau Monne
Preparatory change for implementing indirect descriptors. Change xen_blkbk_{map/unmap} in order to be able to map/unmap a random amount of grants (previously it was limited to BLKIF_MAX_SEGMENTS_PER_REQUEST). Also, remove the usage of pending_req in the map/unmap functions, so we can map/unmap grants without needing to pass a pending_req. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: make the queue of free requests per backendRoger Pau Monne
Remove the last dependency from blkbk by moving the list of free requests to blkif. This change reduces the contention on the list of available requests. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: move pending handles list from blkbk to pending_reqRoger Pau Monne
Moving grant ref handles from blkbk to pending_req will allow us to get rid of the shared blkbk structure. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: implement LRU mechanism for persistent grantsRoger Pau Monne
This mechanism allows blkback to change the number of grants persistently mapped at run time. The algorithm uses a simple LRU mechanism that removes (if needed) the persistent grants that have not been used since the last LRU run, or if all grants have been used it removes the first grants in the list (that are not in use). The algorithm allows the user to change the maximum number of persistent grants, by changing max_persistent_grants in sysfs. Since we are storing the persistent grants used inside the request struct (to be able to mark them as "unused" when unmapping), we no longer need the bitmap (unmap_seg). Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: use balloon pages for all mappingsRoger Pau Monne
Using balloon pages for all granted pages allows us to simplify the logic in blkback, especially in the xen_blkbk_map function, since now we can decide if we want to map a grant persistently or not after we have actually mapped it. This could not be done before because persistent grants used ballooned pages, whereas non-persistent grants used pages from the kernel. This patch also introduces several changes, the first one is that the list of free pages is no longer global, now each blkback instance has it's own list of free pages that can be used to map grants. Also, a run time parameter (max_buffer_pages) has been added in order to tune the maximum number of free pages each blkback instance will keep in it's buffer. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-04-18xen-blkback: print stats about persistent grantsRoger Pau Monne
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-19xen-blkback: don't store dev_bus_addrRoger Pau Monne
dev_bus_addr returned in the grant ref map operation is the mfn of the passed page, there's no need to store it in the persistent grant entry, since we can always get it provided that we have the page. This reduces the memory overhead of persistent grants in blkback. While at it, rename the 'seg[i].buf' to be 'seg[i].offset' as it makes much more sense - as we use that value in bio_add_page which as the fourth argument expects the offset. We hadn't used the physical address as part of this at all. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org [v1: s/buf/offset/] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-19xen-blkback: fix foreach_grant_safe to handle empty listsRoger Pau Monne
We may use foreach_grant_safe in the future with empty lists, so make sure we can handle them. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-18xen-blkback: fix dispatch_rw_block_io() error pathJan Beulich
Commit 7708992 ("xen/blkback: Seperate the bio allocation and the bio submission") consolidated the pendcnt updates to just a single write, neglecting the fact that the error path relied on it getting set to 1 up front (such that the decrement in __end_block_io_op() would actually drop the count to zero, triggering the necessary cleanup actions). Also remove a misleading and a stale (after said commit) comment. CC: stable@vger.kernel.org Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-11xen/blkback: Change statistics counter types to unsignedZoltan Kiss
These values shouldn't be negative, but after an overflow their value can turn into negative, if they are signed. xentop can show bogus values in this case. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Reported-by: Ichiro Ogino <ichiro.ogino@citrix.co.jp> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-11xen/blkback: correctly respond to unknown, non-native requestsDavid Vrabel
If the frontend is using a non-native protocol (e.g., a 64-bit frontend with a 32-bit backend) and it sent an unrecognized request, the request was not translated and the response would have the incorrect ID. This may cause the frontend driver to behave incorrectly or crash. Since the ID field in the request is always in the same place, regardless of the request type we can get the correct ID and make a valid response (which will report BLKIF_RSP_EOPNOTSUPP). This bug affected 64-bit SLES 11 guests when using a 32-bit backend. This guest does a BLKIF_OP_RESERVED_1 (BLKIF_OP_PACKET in the SLES source) and would crash in blkif_int() as the ID in the response would be invalid. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: stable@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-03-01xen/xen-blkback: preq.dev is used without initializedChen Gang
If call xen_vbd_translate failed, the preq.dev will be not initialized. Use blkif->vbd.pdevice instead (still better to print relative info). Note that before commit 01c681d4c70d64cb72142a2823f27c4146a02e63 (xen/blkback: Don't trust the handle from the frontend.) the value bogus, as it was the guest provided value from req->u.rw.handle rather than the actual device. Signed-off-by: Chen Gang <gang.chen@asianux.com> Acked-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen-blkback: use balloon pages for persistent grantsRoger Pau Monne
With current persistent grants implementation we are not freeing the persistent grants after we disconnect the device. Since grant map operations change the mfn of the allocated page, and we can no longer pass it to __free_page without setting the mfn to a sane value, use balloon grant pages instead, as the gntdev device does. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: stable@vger.kernel.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen/blkback: Don't trust the handle from the frontend.Konrad Rzeszutek Wilk
The 'handle' is the device that the request is from. For the life-time of the ring we copy it from a request to a response so that the frontend is not surprised by it. But we do not need it - when we start processing I/Os we have our own 'struct phys_req' which has only most essential information about the request. In fact the 'vbd_translate' ends up over-writing the preq.dev with a value from the backend. This assignment of preq.dev with the 'handle' value is superfluous so lets not do it. Cc: stable@vger.kernel.org Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen-blkback: do not leak mode propertyJan Beulich
"be->mode" is obtained from xenbus_read(), which does a kmalloc() for the message body. The short string is never released, so do it along with freeing "be" itself, and make sure the string isn't kept when backend_changed() doesn't complete successfully (which made it desirable to slightly re-structure that function, so that the error cleanup can be done in one place). Reported-by: Olaf Hering <olaf@aepfle.de> CC: stable@vger.kernel.org Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-12-19Merge branch 'stable/for-jens-3.8' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus Konrad writes: Please git pull the following branch: git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/for-jens-3.8 which has a bug-fix to the xen-blkfront and xen-blkback driver when using the persistent mode. An issue was discovered where LVM disks could not be read correctly and this fixes it. There is also a change in llist.h which has been blessed by akpm.
2012-12-17Merge branch 'for-3.8/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block driver update from Jens Axboe: "Now that the core bits are in, here are the driver bits for 3.8. The branch contains: - A huge pile of drbd bits that were dumped from the 3.7 merge window. Following that, it was both made perfectly clear that there is going to be no more over-the-wall pulls and how the situation on individual pulls can be improved. - A few cleanups from Akinobu Mita for drbd and cciss. - Queue improvement for loop from Lukas. This grew into adding a generic interface for waiting/checking an even with a specific lock, allowing this to be pulled out of md and now loop and drbd is also using it. - A few fixes for xen back/front block driver from Roger Pau Monne. - Partition improvements from Stephen Warren, allowing partiion UUID to be used as an identifier." * 'for-3.8/drivers' of git://git.kernel.dk/linux-block: (609 commits) drbd: update Kconfig to match current dependencies drbd: Fix drbdsetup wait-connect, wait-sync etc... commands drbd: close race between drbd_set_role and drbd_connect drbd: respect no-md-barriers setting also when changed online via disk-options drbd: Remove obsolete check drbd: fixup after wait_even_lock_irq() addition to generic code loop: Limit the number of requests in the bio list wait: add wait_event_lock_irq() interface xen-blkfront: free allocated page xen-blkback: move free persistent grants code block: partition: msdos: provide UUIDs for partitions init: reduce PARTUUID min length to 1 from 36 block: store partition_meta_info.uuid as a string cciss: use check_signature() cciss: cleanup bitops usage drbd: use copy_highpage drbd: if the replication link breaks during handshake, keep retrying drbd: check return of kmalloc in receive_uuids drbd: Broadcast sync progress no more often than once per second drbd: don't try to clear bits once the disk has failed ...
2012-12-07xen-blkback: implement safe iterator for the list of persistent grantsRoger Pau Monne
Change foreach_grant iterator to a safe version, that allows freeing the element while iterating. Also move the free code in free_persistent_gnts to prevent freeing the element before the rb_next call. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org> Cc: xen-devel@lists.xen.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-26xen-blkback: move free persistent grants codeRoger Pau Monne
Move the code that frees persistent grants from the red-black tree to a function. This will make it easier for other consumers to move this to a common place. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-04xen/blkback: persistent-grants fixesRoger Pau Monne
This patch contains fixes for persistent grants implementation v2: * handle == 0 is a valid handle, so initialize grants in blkback setting the handle to BLKBACK_INVALID_HANDLE instead of 0. Reported by Konrad Rzeszutek Wilk. * new_map is a boolean, use "true" or "false" instead of 1 and 0. Reported by Konrad Rzeszutek Wilk. * blkfront announces the persistent-grants feature as feature-persistent-grants, use feature-persistent instead which is consistent with blkback and the public Xen headers. * Add a consistency check in blkfront to make sure we don't try to access segments that have not been set. Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Roger Pau Monne <roger.pau@citrix.com> [v1: The new_map int->bool had already been changed] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-30xen/blkback: Persistent grant maps for xen blk driversRoger Pau Monne
This patch implements persistent grants for the xen-blk{front,back} mechanism. The effect of this change is to reduce the number of unmap operations performed, since they cause a (costly) TLB shootdown. This allows the I/O performance to scale better when a large number of VMs are performing I/O. Previously, the blkfront driver was supplied a bvec[] from the request queue. This was granted to dom0; dom0 performed the I/O and wrote directly into the grant-mapped memory and unmapped it; blkfront then removed foreign access for that grant. The cost of unmapping scales badly with the number of CPUs in Dom0. An experiment showed that when Dom0 has 24 VCPUs, and guests are performing parallel I/O to a ramdisk, the IPIs from performing unmap's is a bottleneck at 5 guests (at which point 650,000 IOPS are being performed in total). If more than 5 guests are used, the performance declines. By 10 guests, only 400,000 IOPS are being performed. This patch improves performance by only unmapping when the connection between blkfront and back is broken. On startup blkfront notifies blkback that it is using persistent grants, and blkback will do the same. If blkback is not capable of persistent mapping, blkfront will still use the same grants, since it is compatible with the previous protocol, and simplifies the code complexity in blkfront. To perform a read, in persistent mode, blkfront uses a separate pool of pages that it maps to dom0. When a request comes in, blkfront transmutes the request so that blkback will write into one of these free pages. Blkback keeps note of which grefs it has already mapped. When a new ring request comes to blkback, it looks to see if it has already mapped that page. If so, it will not map it again. If the page hasn't been previously mapped, it is mapped now, and a record is kept of this mapping. Blkback proceeds as usual. When blkfront is notified that blkback has completed a request, it memcpy's from the shared memory, into the bvec supplied. A record that the {gref, page} tuple is mapped, and not inflight is kept. Writes are similar, except that the memcpy is peformed from the supplied bvecs, into the shared pages, before the request is put onto the ring. Blkback stores a mapping of grefs=>{page mapped to by gref} in a red-black tree. As the grefs are not known apriori, and provide no guarantees on their ordering, we have to perform a search through this tree to find the page, for every gref we receive. This operation takes O(log n) time in the worst case. In blkfront grants are stored using a single linked list. The maximum number of grants that blkback will persistenly map is currently set to RING_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST, to prevent a malicios guest from attempting a DoS, by supplying fresh grefs, causing the Dom0 kernel to map excessively. If a guest is using persistent grants and exceeds the maximum number of grants to map persistenly the newly passed grefs will be mapped and unmaped. Using this approach, we can have requests that mix persistent and non-persistent grants, and we need to handle them correctly. This allows us to set the maximum number of persistent grants to a lower value than RING_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST, although setting it will lead to unpredictable performance. In writing this patch, the question arrises as to if the additional cost of performing memcpys in the guest (to/from the pool of granted pages) outweigh the gains of not performing TLB shootdowns. The answer to that question is `no'. There appears to be very little, if any additional cost to the guest of using persistent grants. There is perhaps a small saving, from the reduced number of hypercalls performed in granting, and ending foreign access. Signed-off-by: Oliver Chick <oliver.chick@citrix.com> Signed-off-by: Roger Pau Monne <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v1: Fixed up the misuse of bool as int]
2012-10-30xen/blkback: Change xen_vbd's flush_support and discard_secure to have type ↵Oliver Chick
unsigned int, rather than bool Changing the type of bdev parameters to be unsigned int :1, rather than bool. This is more consistent with the types of other features in the block drivers. Signed-off-by: Oliver Chick <oliver.chick@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-30xen/blkback: use kmem_cache_zalloc instead of kmem_cache_alloc/memsetWei Yongjun
Using kmem_cache_zalloc() instead of kmem_cache_alloc() and memset(). spatch with a semantic match is used to found this problem. (http://coccinelle.lip6.fr/) Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-30xen/blkback: Fix compile warningKonrad Rzeszutek Wilk
drivers/block/xen-blkback/xenbus.c:260:5: warning: symbol 'xenvbd_sysfs_addif' was not declared. Should it be static? drivers/block/xen-blkback/xenbus.c:284:6: warning: symbol 'xenvbd_sysfs_delif' was not declared. Should it be static? Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-07Merge tag 'stable/for-linus-3.7-arm-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Pull ADM Xen support from Konrad Rzeszutek Wilk: Features: * Allow a Linux guest to boot as initial domain and as normal guests on Xen on ARM (specifically ARMv7 with virtualized extensions). PV console, block and network frontend/backends are working. Bug-fixes: * Fix compile linux-next fallout. * Fix PVHVM bootup crashing. The Xen-unstable hypervisor (so will be 4.3 in a ~6 months), supports ARMv7 platforms. The goal in implementing this architecture is to exploit the hardware as much as possible. That means use as little as possible of PV operations (so no PV MMU) - and use existing PV drivers for I/Os (network, block, console, etc). This is similar to how PVHVM guests operate in X86 platform nowadays - except that on ARM there is no need for QEMU. The end result is that we share a lot of the generic Xen drivers and infrastructure. Details on how to compile/boot/etc are available at this Wiki: http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions and this blog has links to a technical discussion/presentations on the overall architecture: http://blog.xen.org/index.php/2012/09/21/xensummit-sessions-new-pvh-virtualisation-mode-for-arm-cortex-a15arm-servers-and-x86/ * tag 'stable/for-linus-3.7-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (21 commits) xen/xen_initial_domain: check that xen_start_info is initialized xen: mark xen_init_IRQ __init xen/Makefile: fix dom-y build arm: introduce a DTS for Xen unprivileged virtual machines MAINTAINERS: add myself as Xen ARM maintainer xen/arm: compile netback xen/arm: compile blkfront and blkback xen/arm: implement alloc/free_xenballooned_pages with alloc_pages/kfree xen/arm: receive Xen events on ARM xen/arm: initialize grant_table on ARM xen/arm: get privilege status xen/arm: introduce CONFIG_XEN on ARM xen: do not compile manage, balloon, pci, acpi, pcpu and cpu_hotplug on ARM xen/arm: Introduce xen_ulong_t for unsigned long xen/arm: Xen detection and shared_info page mapping docs: Xen ARM DT bindings xen/arm: empty implementation of grant_table arch specific functions xen/arm: sync_bitops xen/arm: page.h definitions xen/arm: hypercalls ...
2012-09-12xen/m2p: do not reuse kmap_op->dev_bus_addrStefano Stabellini
If the caller passes a valid kmap_op to m2p_add_override, we use kmap_op->dev_bus_addr to store the original mfn, but dev_bus_addr is part of the interface with Xen and if we are batching the hypercalls it might not have been written by the hypervisor yet. That means that later on Xen will write to it and we'll think that the original mfn is actually what Xen has written to it. Rather than "stealing" struct members from kmap_op, keep using page->index to store the original mfn and add another parameter to m2p_remove_override to get the corresponding kmap_op instead. It is now responsibility of the caller to keep track of which kmap_op corresponds to a particular page in the m2p_override (gntdev, the only user of this interface that passes a valid kmap_op, is already doing that). CC: stable@kernel.org Reported-and-Tested-By: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-08-08xen/arm: compile blkfront and blkbackStefano Stabellini
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-06-13Merge branch 'stable/for-jens-3.5' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus
2012-05-30xen/blkback: Copy id field when doing BLKIF_DISCARD.Konrad Rzeszutek Wilk
We weren't copying the id field so when we sent the response back to the frontend (especially with a 64-bit host and 32-bit guest), we ended up using a random value. This lead to the frontend crashing as it would try to pass to __blk_end_request_all a NULL 'struct request' (b/c it would use the 'id' to find the proper 'struct request' in its shadow array) and end up crashing: BUG: unable to handle kernel NULL pointer dereference at 000000e4 IP: [<c0646d4c>] __blk_end_request_all+0xc/0x40 .. snip.. EIP is at __blk_end_request_all+0xc/0x40 .. snip.. [<ed95db72>] blkif_interrupt+0x172/0x330 [xen_blkfront] This fixes the bug by passing in the proper id for the response. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=824641 CC: stable@kernel.org Tested-by: William Dauchy <wdauchy@gmail.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-04-18xen/blkback: Fix warning error.Konrad Rzeszutek Wilk
drivers/block/xen-blkback/xenbus.c: In function 'xen_blkbk_discard': drivers/block/xen-blkback/xenbus.c:419:4: warning: passing argument 1 of 'dev_warn' makes pointer from integer without a cast +[enabled by default] include/linux/device.h:894:5: note: expected 'const struct device *' but argument is of type 'long int' It is unclear how that mistake made it in. It surely is wrong. Acked-by: Jens Axboe <axboe@kernel.dk> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-03-24xen/blkback: Make optional features be really optional.Konrad Rzeszutek Wilk
They were using the xenbus_dev_fatal() function which would change the state of the connection immediately. Which is not what we want when we advertise optional features. So make 'feature-discard','feature-barrier','feature-flush-cache' optional. Suggested-by: Jan Beulich <JBeulich@suse.com> [v1: Made the discard function void and static] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-03-24xen/blkback: Squash the discard support for 'file' and 'phy' type.Konrad Rzeszutek Wilk
The only reason for the distinction was for the special case of 'file' (which is assumed to be loopback device), was to reach inside the loopback device, find the underlaying file, and call fallocate on it. Fortunately "xen-blkback: convert hole punching to discard request on loop devices" removes that use-case and we now based the discard support based on blk_queue_discard(q) and extract all appropriate parameters from the 'struct request_queue'. CC: Li Dongyang <lidongyang@novell.com> Acked-by: Jan Beulich <JBeulich@suse.com> [v1: Dropping pointless initializer and keeping blank line] [v2: Remove the kfree as it is not used anymore] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>