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* writeback: do not lose wake-ups in the forker thread - 1Artem Bityutskiy2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | Currently the forker thread can lose wake-ups which may lead to unnecessary delays in processing bdi works. E.g., consider the following scenario. 1. 'bdi_forker_thread()' walks the 'bdi_list', finds out there is nothing to do, and is about to finish the loop. 2. A bdi thread decides to exit because it was inactive for long time. 3. 'bdi_queue_work()' adds a work to the bdi which just exited, so it wakes up the forker thread. 4. but 'bdi_forker_thread()' executes 'set_current_state(TASK_INTERRUPTIBLE)' and goes sleep. We lose a wake-up. Losing the wake-up is not fatal, but this means that the bdi work processing will be delayed by up to 5 sec. This race is theoretical, I never hit it, but it is worth fixing. The fix is to execute 'set_current_state(TASK_INTERRUPTIBLE)' _before_ walking 'bdi_list', not after. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: fix possible race when creating bdi threadsArtem Bityutskiy2010-08-07
| | | | | | | | | | | | | | | | | | | | | This patch fixes a very unlikely race condition on the bdi forker thread error path: when bdi thread creation fails, 'bdi->wb.task' may contain the error code for a short period of time. If at the same time someone submits a work to this bdi, we can end up with an oops 'bdi_queue_work()' while executing 'wake_up_process(wb->task)'. This patch fixes the issue by introducing a temporary variable 'task' and storing the possible error code there, so that 'wb->task' would never take erroneous values. Note, this race is very unlikely and I never hit it, so it is theoretical, but nevertheless worth fixing. This patch also merges 2 comments which were previously separate. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: harmonize writeback threads namingArtem Bityutskiy2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The write-back code mixes words "thread" and "task" for the same things. This is not a big deal, but still an inconsistency. hch: a convention I tend to use and I've seen in various places is to always use _task for the storage of the task_struct pointer, and thread everywhere else. This especially helps with having foo_thread for the actual thread and foo_task for a global variable keeping the task_struct pointer This patch renames: * 'bdi_add_default_flusher_task()' -> 'bdi_add_default_flusher_thread()' * 'bdi_forker_task()' -> 'bdi_forker_thread()' because bdi threads are 'bdi_writeback_thread()', so these names are more consistent. This patch also amends commentaries and makes them refer the forker and bdi threads as "thread", not "task". Also, while on it, make 'bdi_add_default_flusher_thread()' declaration use 'static void' instead of 'void static' and make checkpatch.pl happy. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* coda: fixup clash with block layer REQ_* definesJens Axboe2010-08-07
| | | | | | | CODA should not be using defines in the global name space of that nature, prefix them with CODA_. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* bio, fs: separate out bio_types.h and define READ/WRITE constants in terms ↵Tejun Heo2010-08-07
| | | | | | | | | | | | | | | of BIO_RW_* flags linux/fs.h hard coded READ/WRITE constants which should match BIO_RW_* flags. This is fragile and caused breakage during BIO_RW_* flag rearrangement. The hardcoding is to avoid include dependency hell. Create linux/bio_types.h which contatins definitions for bio data structures and flags and include it from bio.h and fs.h, and make fs.h define all READ/WRITE related constants in terms of BIO_RW_* flags. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* bio, fs: update RWA_MASK, READA and SWRITE to match the corresponding ↵Tejun Heo2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | BIO_RW_* bits Commit a82afdf (block: use the same failfast bits for bio and request) moved BIO_RW_* bits around such that they match up with REQ_* bits. Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_* bits. READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4 instead of bit 1, breaking RWA_MASK, READA and SWRITE. This patch updates RWA_MASK, READA and SWRITE such that they match the BIO_RW_* bits again. A follow up patch will update the definitions to directly use BIO_RW_* bits so that this kind of breakage won't happen again. Neil also spotted missing RWA_MASK conversion. Stable: The offending commit a82afdf was released with v2.6.32, so this patch should be applied to all kernels since then but it must _NOT_ be applied to kernels earlier than that. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net> Root-caused-by: Neil Brown <neilb@suse.de> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: disallow FS recursion from sb_issue_discard allocationMike Snitzer2010-08-07
| | | | | | | | | | | Filesystems can call sb_issue_discard on a memory reclaim path (e.g. ext4 calls sb_issue_discard during journal commit). Use GFP_NOFS in sb_issue_discard to avoid recursing back into the FS. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cpqarray: check put_user() resultKulikov Vasiliy2010-08-07
| | | | | | | | put_user() may fail, if so return -EFAULT. Signed-off-by: Kulikov Vasiliy <segooon@gmail.com> Acked-by: Mike Miller <mike.miller@hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: remove wb in get_next_work_itemMinchan Kim2010-08-07
| | | | | | | | | | 83ba7b07 cleans up the writeback. So we don't use wb any more in get_next_work_item. Let's remove unnecessary argument. CC: Christoph Hellwig <hch@lst.de> Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* splice: fix misuse of SPLICE_F_NONBLOCKMiklos Szeredi2010-08-07
| | | | | | | | | | | | | | | | | | SPLICE_F_NONBLOCK is clearly documented to only affect blocking on the pipe. In __generic_file_splice_read(), however, it causes an EAGAIN if the page is currently being read. This makes it impossible to write an application that only wants failure if the pipe is full. For example if the same process is handling both ends of a pipe and isn't otherwise able to determine whether a splice to the pipe will fill it or not. We could make the read non-blocking on O_NONBLOCK or some other splice flag, but for now this is the simplest fix. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* xen/blkfront: Use QUEUE_ORDERED_DRAIN for old backendsJeremy Fitzhardinge2010-08-07
| | | | | | | | If there's no feature-barrier key in xenstore, then it means its a fairly old backend which does uncached in-order writes, which means ORDERED_DRAIN is appropriate. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* xen/blkfront: use tagged queuing for barriersJeremy Fitzhardinge2010-08-07
| | | | | | | | | | When barriers are supported, then use QUEUE_ORDERED_TAG to tell the block subsystem that it doesn't need to do anything else with the barriers. Previously we used ORDERED_DRAIN which caused the block subsystem to drain all pending IO before submitting the barrier, which would be very expensive. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* scsi: use REQ_TYPE_FS for flush requestFUJITA Tomonori2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | scsi-ml uses REQ_TYPE_BLOCK_PC for flush requests from file systems. The definition of REQ_TYPE_BLOCK_PC is that we don't retry requests even when we can (e.g. UNIT ATTENTION) and we send the response to the callers (then the callers can decide what they want). We need a workaround such as the commit 77a4229719e511a0d38d9c355317ae1469adeb54 to retry BLOCK_PC flush requests. We will need the similar workaround for discard requests too since SCSI-ml handle them as BLOCK_PC internally. This uses REQ_TYPE_FS for flush requests from file systems instead of REQ_TYPE_BLOCK_PC. scsi-ml retries only REQ_TYPE_FS requests that have data to transfer when we can retry them (e.g. UNIT_ATTENTION). However, we also need to retry REQ_TYPE_FS requests without data because the callers don't. This also changes scsi_check_sense() to retry all the REQ_TYPE_FS requests when appropriate. Thanks to scsi_noretry_cmd(), REQ_TYPE_BLOCK_PC requests don't be retried as before. Note that basically, this reverts the commit 77a4229719e511a0d38d9c355317ae1469adeb54 since now we use REQ_TYPE_FS for flush requests. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: set up rq->rq_disk properly for flush requestsFUJITA Tomonori2010-08-07
| | | | | | | | q->bar_rq.rq_disk is NULL. Use the rq_disk of the original request instead. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: set REQ_TYPE_FS on flush requestsFUJITA Tomonori2010-08-07
| | | | | | | | | | the block layer doesn't set rq->cmd_type on flush requests. By definition, it should be REQ_TYPE_FS (the lower layers build a command and interpret the result of it, that is, the block layer doesn't know the details). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* floppy: make controller constStephen Hemminger2010-08-07
| | | | | | | | The struct cont_t is just a set of virtual function pointers. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* drivers/block: use memdup_userJulia Lawall2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use memdup_user when user data is immediately copied into the allocated region. Some checkpatch cleanups in nearby code. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression from,to,size,flag; position p; identifier l1,l2; @@ - to = \(kmalloc@p\|kzalloc@p\)(size,flag); + to = memdup_user(from,size); if ( - to==NULL + IS_ERR(to) || ...) { <+... when != goto l1; - -ENOMEM + PTR_ERR(to) ...+> } - if (copy_from_user(to, from, size) != 0) { - <+... when != goto l2; - -EFAULT - ...+> - } // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Cc: Chirag Kantharia <chirag.kantharia@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* scsi: convert discard to REQ_TYPE_FS from REQ_TYPE_BLOCK_PCFUJITA Tomonori2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | Jens, any reason why this isn't included in your for-2.6.36 yet? = From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Subject: [PATCH resend] scsi: convert discard to REQ_TYPE_FS from REQ_TYPE_BLOCK_PC The block layer (file systems) sends discard requests as REQ_TYPE_FS (the role of REQ_TYPE_FS is that setting up commands and interpreting the results). But SCSI-ml treats discard requests as REQ_TYPE_BLOCK_PC. scsi-ml can handle discard requests as REQ_TYPE_FS easily. scsi_setup_discard_cmnd() sets up struct request and the bio nicely. Only remaining issue is that discard requests can't be completed partially so we need to modify sd_done. This conversion also fixes the problem that discard requests aren't retried when possible (e.g. UNIT ATTENTION). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: cleanup interrupt_not_for_usStephen M. Cameron2010-08-07
| | | | | | | | | | | cciss: cleanup interrupt_not_for_us In the case of MSI/MSIX interrutps, we don't need to check if the interrupt is for us, and in the case of the intx interrupt handler, when checking if the interrupt is for us, we don't need to check if we're using MSI/MSIX, we know we're not. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: change printks to dev_warn, etc.Stephen M. Cameron2010-08-07
| | | | | | | cciss: change printks to dev_warn, etc. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: separate cmd_alloc() and cmd_special_alloc()Stephen M. Cameron2010-08-07
| | | | | | | | | | | | | cciss: separate cmd_alloc() and cmd_special_alloc() cmd_alloc() took a parameter which caused it to either allocate from a pre-allocated pool, or allocate using pci_alloc_consistent. This parameter is always known at compile time, so this would be better handled by breaking the function into two functions and differentiating the cases by function names. Same goes for cmd_free(). Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: use consistent variable namesStephen M. Cameron2010-08-07
| | | | | | | | | cciss: use consistent variable names "h", for the hba structure and "c" for the command structures. and get rid of trivial CCISS_LOCK macro. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: forbid hard reset of 640x boardsStephen M. Cameron2010-08-07
| | | | | | | | | | | | | | cciss: forbid hard reset of 640x boards The 6402/6404 are two PCI devices -- two Smart Array controllers -- that fit into one slot. It is possible to reset them independently, however, they share a battery backed cache module. One of the pair controls the cache and the 2nd one access the cache through the first one. If you reset the one controlling the cache, the other one will not be a happy camper. So we just forbid resetting this conjoined mess. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: sanitize max commandsStephen M. Cameron2010-08-07
| | | | | | | | | | | | cciss: sanitize max commands Some controllers might try to tell us they support 0 commands in performant mode. This is a lie told by buggy firmware. We have to be wary of this lest we try to allocate a negative number of command blocks, which will be treated as unsigned, and get an out of memory condition. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: fix hard reset code.Stephen M. Cameron2010-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | cciss: Fix hard reset code. Smart Array controllers newer than the P600 do not honor the PCI power state method of resetting the controllers. Instead, in these cases we can get them to reset via the "doorbell" register. This escaped notice until we began using "performant" mode because the fact that the controllers did not reset did not normally impede subsequent operation, and so things generally appeared to "work". Once the performant mode code was added, if the controller does not reset, it remains in performant mode. The code immediately after the reset presumes the controller is in "simple" mode (which previously, it had remained in simple mode the whole time). If the controller remains in performant mode any code which presumes it is in simple mode will not work. So the reset needs to be fixed. Unfortunately there are some controllers which cannot be reset by either method. (eg. p800). We detect these cases by noticing that the controller seems to remain in performant mode even after a reset has been attempted. In those cases we ignore the controller, as any commands outstanding on it will result in stale completions. To sum up, we try to do a better job of resetting the controller if "reset_devices" is set, and if it doesn't work, we ignore that controller. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_reset_devices()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_reset_devices() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_find_cfg_addrs.Stephen M. Cameron2010-08-07
| | | | | | | | Rationale for this is that I will also need to use this code in fixing kdump host reset code prior to having the hba structure. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_enter_performant_modeStephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_enter_performant_mode Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_wait_for_mode_change_ack()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_wait_for_mode_change_ack() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: make cciss_put_controller_into_performant_mode as __devinitStephen M. Cameron2010-08-07
| | | | | | | cciss: make cciss_put_controller_into_performant_mode as __devinit Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: cleanup some debug ifdefsStephen M. Cameron2010-08-07
| | | | | | | cciss: cleanup some debug ifdefs Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_p600_dma_prefetch_quirk()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_p600_dma_prefetch_quirk() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_enable_scsi_prefetch()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_enable_scsi_prefetch() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out CISS_signature_present()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out CISS_signature_present() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_find_board_paramsStephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_find_board_params Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: fix leak of ioremapped memoryStephen M. Cameron2010-08-07
| | | | | | | | cciss: fix leak of ioremapped memory in cciss_pci_init error path. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_find_cfgtablesStephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_find_cfgtables Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_wait_for_board_ready()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_wait_for_board_ready() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_find_memory_BAR()Stephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_find_memory_BAR() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: remove board_id parameter from cciss_interrupt_mode()Stephen M. Cameron2010-08-07
| | | | | | | cciss: remove board_id parameter from cciss_interrupt_mode() Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_board_disabledStephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_board_disabled Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: factor out cciss_lookup_board_idStephen M. Cameron2010-08-07
| | | | | | | cciss: factor out cciss_lookup_board_id Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: save pdev pointer in per hba structure early to avoid passing it ↵Stephen M. Cameron2010-08-07
| | | | | | | | | around so much. cciss: save pdev pointer in per hba structure early to avoid passing it around so much. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* cciss: Set the performant mode bit in the scsi half of the driverStephen M. Cameron2010-08-07
| | | | | | | | | | | | | | cciss: Set the performant mode bit in the scsi half of the driver In a couple of places, the performant mode bit wasn't being set in the scsi half of the driver, causing commands to seem to hang. Use enqueue_cmd_and_start_io() where appropriate. This fixes a bug that echo engage scsi > /proc/driver/cciss/cciss0 would hang. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkfront: Klog the unclean release pathDaniel Stodden2010-08-07
| | | | | | Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkfront: Remove obsolete info->usersDaniel Stodden2010-08-07
| | | | | | | | This is just bd_openers, protected by the bd_mutex. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkfront: Remove obsolete info->usersDaniel Stodden2010-08-07
| | | | | | | | This is just bd_openers, protected by the bd_mutex. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkfront: Lock blockfront_info during xbdev removalDaniel Stodden2010-08-07
| | | | | | | | | | Same approach as blkfront_closing: * Grab the bdev safely, holding the info mutex. * Zap xbdev safely, holding the info mutex. * Try bdev removal safely, holding bd_mutex. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* blkfront: Fix blkfront backend switch race (bdev release)Daniel Stodden2010-08-07
| | | | | | | | | | | | | | | We cannot read backend state within bdev operations, because it risks grabbing the state change before xenbus gets to do it. Fixed by tracking deferral with a frontend switch to Closing. State exposure isn't strictly necessary, but the backends won't mind. For a 'clean' deferral this seems actually a more decent protocol than raising errors. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkfront: Fix blkfront backend switch race (bdev open)Daniel Stodden2010-08-07
| | | | | | | | | | | | | We need not mind if users grab a late handle on a closing disk. We probably even should not. But we have to make sure it's not a dead one already Let the bdev deal with a gendisk deleted under its feet. Takes the info mutex to decide a race against backend closing. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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