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* md: Ensure an md array never has too many devices.NeilBrown2009-02-06
| | | | | | | | | | | | | | | | | | | | | | | | Each different metadata format supported by md supports a different maximum number of devices. We really should be enforcing this maximum in the kernel, but we aren't quite doing that properly. We currently only enforce it at the 'hot_add' point, which is an older interface which is not used by current userspace. We need to also enforce it at 'add_new_disk' time for active arrays and at 'do_md_run' time when starting a new array. So move the test from 'hot_add' into 'bind_rdev_to_array' which is called from both 'hot_add' and 'add_new_disk, and add a new test in 'analyse_sbs' which is called from 'do_md_run'. This bug (or missing feature) has been around "forever" and so the patch is suitable for any -stable that is currently maintained. Cc: stable@kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
* md: Fix a bug in linear.c causing which_dev() to return the wrong device.Andre Noll2009-02-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ab5bd5cbc8d4b868378d062eed3d4240930fbb86 introduced the following bug in linear software raid for large arrays on 32 bit machines: which_dev() computes the device holding a given sector by shifting down the sector number to a 32 bit range, dividing by the array spacing and looking up the resulting index in the hash table of the array. Because the computed index might be slightly too small, a loop at the end of which_dev() increases the index until the given sector actually falls into the range of the device associated with that index. The changes of the above mentioned commit caused this loop to check whether the _index_ rather than the sector number is small enough, effectively bypassing the loop and thus possibly returning the wrong device. As reported by Simon Kirby, this leads to errors such as linear_make_request: Sector 2340486136 out of bounds on dev sdi: 156301312 sectors, offset 2109870464 Fix this bug by introducing a local variable for the index so that the variable containing the passed sector is left unchanged. Cc: stable@kernel.org Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: Allow read error in a single drive raid1 to be passed up.NeilBrown2009-02-05
| | | | | | | | | | | | | | If a raid1 only has a single working device and gets a read error, we choose to simply return that error up to the filesystem (or whatever) rather than failing the whole array. However the codes doesn't quite do that. We attempt a readbalance which allocates the same drive, so we retry the read - indefinitely. Instead: If read_balance in the error case chooses the same drive that just failed, treat it as a failure and don't retry. Signed-off-by: NeilBrown <neilb@suse.de>
* md: don't retry recovery of raid1 that fails due to error on source drive.NeilBrown2009-01-08
| | | | | | | | | | | | | | | | If a raid1 has only one working drive and it has a sector which gives an error on read, then an attempt to recover onto a spare will fail, but as the single remaining drive is not removed from the array, the recovery will be immediately re-attempted, resulting in an infinite recovery loop. So detect this situation and don't retry recovery once an error on the lone remaining drive is detected. Allow recovery to be retried once every time a spare is added in case the problem wasn't actually a media error. Signed-off-by: NeilBrown <neilb@suse.de>
* md: Allow md devices to be created by name.NeilBrown2009-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | Using sequential numbers to identify md devices is somewhat artificial. Using names can be a lot more user-friendly. Also, creating md devices by opening the device special file is a bit awkward. So this patch provides a new option for creating and naming devices. Writing a name such as "md_home" to /sys/modules/md_mod/parameters/new_array will cause an array with that name to be created. It will appear in /sys/block/ /proc/partitions and /proc/mdstat as 'md_home'. It will have an arbitrary minor number allocated. md devices that a created by an open are destroyed on the last close when the device is inactive. For named md devices, they will not be destroyed until the array is explicitly stopped, either with the STOP_ARRAY ioctl or by writing 'clear' to /sys/block/md_XXXX/md/array_state. The name of the array must start 'md_' to avoid conflict with other devices. Signed-off-by: NeilBrown <neilb@suse.de>
* md: make devices disappear when they are no longer needed.NeilBrown2009-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently md devices, once created, never disappear until the module is unloaded. This is essentially because the gendisk holds a reference to the mddev, and the mddev holds a reference to the gendisk, this a circular reference. If we drop the reference from mddev to gendisk, then we need to ensure that the mddev is destroyed when the gendisk is destroyed. However it is not possible to hook into the gendisk destruction process to enable this. So we drop the reference from the gendisk to the mddev and destroy the gendisk when the mddev gets destroyed. However this has a complication. Between the call __blkdev_get->get_gendisk->kobj_lookup->md_probe and the call __blkdev_get->md_open there is no obvious way to hold a reference on the mddev any more, so unless something is done, it will disappear and gendisk will be destroyed prematurely. Also, once we decide to destroy the mddev, there will be an unlockable moment before the gendisk is unlinked (blk_unregister_region) during which a new reference to the gendisk can be created. We need to ensure that this reference can not be used. i.e. the ->open must fail. So: 1/ in md_probe we set a flag in the mddev (hold_active) which indicates that the array should be treated as active, even though there are no references, and no appearance of activity. This is cleared by md_release when the device is closed if it is no longer needed. This ensures that the gendisk will survive between md_probe and md_open. 2/ In md_open we check if the mddev we expect to open matches the gendisk that we did open. If there is a mismatch we return -ERESTARTSYS and modify __blkdev_get to retry from the top in that case. In the -ERESTARTSYS sys case we make sure to wait until the old gendisk (that we succeeded in opening) is really gone so we loop at most once. Some udev configurations will always open an md device when it first appears. If we allow an md device that was just created by an open to disappear on an immediate close, then this can race with such udev configurations and result in an infinite loop the device being opened and closed, then re-open due to the 'ADD' even from the first open, and then close and so on. So we make sure an md device, once created by an open, remains active at least until some md 'ioctl' has been made on it. This means that all normal usage of md devices will allow them to disappear promptly when not needed, but the worst that an incorrect usage will do it cause an inactive md device to be left in existence (it can easily be removed). As an array can be stopped by writing to a sysfs attribute echo clear > /sys/block/mdXXX/md/array_state we need to use scheduled work for deleting the gendisk and other kobjects. This allows us to wait for any pending gendisk deletion to complete by simply calling flush_scheduled_work(). Signed-off-by: NeilBrown <neilb@suse.de>
* md: centralise all freeing of an 'mddev' in 'md_free'NeilBrown2009-01-08
| | | | | | | | | md_free is the .release handler for the md kobj_type. So it makes sense to release all the objects referenced by the mddev in there, rather than just prior to calling kobject_put for what we think is the last time. Signed-off-by: NeilBrown <neilb@suse.de>
* md: move allocation of ->queue from mddev_find to md_probeNeilBrown2009-01-08
| | | | | | | | | | It is more balanced to just do simple initialisation in mddev_find, which allocates and links a new md device, and leave all the more sophisticated allocation to md_probe (which calls mddev_find). md_probe already allocated the gendisk. It should allocate the queue too. Signed-off-by: NeilBrown <neilb@suse.de>
* md: need another print_sb for mdp_superblock_1Cheng Renquan2009-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md_print_devices is called in two code path: MD_BUG(...), and md_ioctl with PRINT_RAID_DEBUG. it will dump out all in use md devices information; However, it wrongly processed two types of superblock in one: The header file <linux/raid/md_p.h> has defined two types of superblock, struct mdp_superblock_s (typedefed with mdp_super_t) according to md with metadata 0.90, and struct mdp_superblock_1 according to md with metadata 1.0 and later, These two types of superblock are very different, The md_print_devices code processed them both in mdp_super_t, that would lead to wrong informaton dump like: [ 6742.345877] [ 6742.345887] md: ********************************** [ 6742.345890] md: * <COMPLETE RAID STATE PRINTOUT> * [ 6742.345892] md: ********************************** [ 6742.345896] md1: <ram7><ram6><ram5><ram4> [ 6742.345907] md: rdev ram7, SZ:00065472 F:0 S:1 DN:3 [ 6742.345909] md: rdev superblock: [ 6742.345914] md: SB: (V:0.90.0) ID:<42ef13c7.598c059a.5f9f1645.801e9ee6> CT:4919856d [ 6742.345918] md: L5 S00065472 ND:4 RD:4 md1 LO:2 CS:65536 [ 6742.345922] md: UT:4919856d ST:1 AD:4 WD:4 FD:0 SD:0 CSUM:b7992907 E:00000001 [ 6742.345924] D 0: DISK<N:0,(1,8),R:0,S:6> [ 6742.345930] D 1: DISK<N:1,(1,10),R:1,S:6> [ 6742.345933] D 2: DISK<N:2,(1,12),R:2,S:6> [ 6742.345937] D 3: DISK<N:3,(1,14),R:3,S:6> [ 6742.345942] md: THIS: DISK<N:3,(1,14),R:3,S:6> ... [ 6742.346058] md0: <ram3><ram2><ram1><ram0> [ 6742.346067] md: rdev ram3, SZ:00065472 F:0 S:1 DN:3 [ 6742.346070] md: rdev superblock: [ 6742.346073] md: SB: (V:1.0.0) ID:<369aad81.00000000.00000000.00000000> CT:9a322a9c [ 6742.346077] md: L-1507699579 S976570180 ND:48 RD:0 md0 LO:65536 CS:196610 [ 6742.346081] md: UT:00000018 ST:0 AD:131048 WD:0 FD:8 SD:0 CSUM:00000000 E:00000000 [ 6742.346084] D 0: DISK<N:-1,(-1,-1),R:-1,S:-1> [ 6742.346089] D 1: DISK<N:-1,(-1,-1),R:-1,S:-1> [ 6742.346092] D 2: DISK<N:-1,(-1,-1),R:-1,S:-1> [ 6742.346096] D 3: DISK<N:-1,(-1,-1),R:-1,S:-1> [ 6742.346102] md: THIS: DISK<N:0,(0,0),R:0,S:0> ... [ 6742.346219] md: ********************************** [ 6742.346221] Here md1 is metadata 0.90.0, and md0 is metadata 1.2 After some more code to distinguish these two types of superblock, in this patch, it will generate dump information like: [ 7906.755790] [ 7906.755799] md: ********************************** [ 7906.755802] md: * <COMPLETE RAID STATE PRINTOUT> * [ 7906.755804] md: ********************************** [ 7906.755808] md1: <ram7><ram6><ram5><ram4> [ 7906.755819] md: rdev ram7, SZ:00065472 F:0 S:1 DN:3 [ 7906.755821] md: rdev superblock (MJ:0): [ 7906.755826] md: SB: (V:0.90.0) ID:<3fca7a0d.a612bfed.5f9f1645.801e9ee6> CT:491989f3 [ 7906.755830] md: L5 S00065472 ND:4 RD:4 md1 LO:2 CS:65536 [ 7906.755834] md: UT:491989f3 ST:1 AD:4 WD:4 FD:0 SD:0 CSUM:00fb52ad E:00000001 [ 7906.755836] D 0: DISK<N:0,(1,8),R:0,S:6> [ 7906.755842] D 1: DISK<N:1,(1,10),R:1,S:6> [ 7906.755845] D 2: DISK<N:2,(1,12),R:2,S:6> [ 7906.755849] D 3: DISK<N:3,(1,14),R:3,S:6> [ 7906.755855] md: THIS: DISK<N:3,(1,14),R:3,S:6> ... [ 7906.755972] md0: <ram3><ram2><ram1><ram0> [ 7906.755981] md: rdev ram3, SZ:00065472 F:0 S:1 DN:3 [ 7906.755984] md: rdev superblock (MJ:1): [ 7906.755989] md: SB: (V:1) (F:0) Array-ID:<5fbcf158:55aa:5fbe:9a79:1e939880dcbd> [ 7906.755990] md: Name: "DG5:0" CT:1226410480 [ 7906.755998] md: L5 SZ130944 RD:4 LO:2 CS:128 DO:24 DS:131048 SO:8 RO:0 [ 7906.755999] md: Dev:00000003 UUID: 9194d744:87f7:a448:85f2:7497b84ce30a [ 7906.756001] md: (F:0) UT:1226410480 Events:0 ResyncOffset:-1 CSUM:0dbcd829 [ 7906.756003] md: (MaxDev:384) ... [ 7906.756113] md: ********************************** [ 7906.756116] this md0 (metadata 1.2) information dumping is exactly according to struct mdp_superblock_1. Signed-off-by: Cheng Renquan <crquan@gmail.com> Cc: Neil Brown <neilb@suse.de> Cc: Dan Williams <dan.j.williams@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: use list_for_each_entry macro directlyCheng Renquan2009-01-08
| | | | | | | | | | | | | | | | | The rdev_for_each macro defined in <linux/raid/md_k.h> is identical to list_for_each_entry_safe, from <linux/list.h>, it should be defined to use list_for_each_entry_safe, instead of reinventing the wheel. But some calls to each_entry_safe don't really need a safe version, just a direct list_for_each_entry is enough, this could save a temp variable (tmp) in every function that used rdev_for_each. In this patch, most rdev_for_each loops are replaced by list_for_each_entry, totally save many tmp vars; and only in the other situations that will call list_del to delete an entry, the safe version is used. Signed-off-by: Cheng Renquan <crquan@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0: make hash_spacing and preshift sector-based.Andre Noll2009-01-08
| | | | | | | | | | | | | | | | | This patch renames the hash_spacing and preshift members of struct raid0_private_data to spacing and sector_shift respectively and changes the semantics as follows: We always have spacing = 2 * hash_spacing. In case sizeof(sector_t) > sizeof(u32) we also have sector_shift = preshift + 1 while sector_shift = preshift = 0 otherwise. Note that the values of nb_zone and zone are unaffected by these changes because in the sector_div() preceeding the assignement of these two variables both arguments double. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0: Represent the size of strip zones in sectors.Andre Noll2009-01-08
| | | | | | | This completes the block -> sector conversion of struct strip_zone. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0 create_strip_zones(): Add KERN_INFO/KERN_ERR to printk's.Andre Noll2009-01-08
| | | | | | | This patch consists only of these trivial changes. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0 create_strip_zones(): Make two local variables sector-based.Andre Noll2009-01-08
| | | | | | | | | | | | | current_offset and curr_zone_offset stored the corresponding offsets as 1K quantities. Rename them to current_start and curr_zone_start to match the naming of struct strip_zone and store the offsets as sector counts. Also, add KERN_INFO to the printk() affected by this change to make checkpatch happy. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0: Represent zone->zone_offset in sectors.Andre Noll2009-01-08
| | | | | | | | For the same reason as in the previous patch, rename it from zone_offset to zone_start. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0: Represent device offset in sectors.Andre Noll2009-01-08
| | | | | | | | Rename zone->dev_offset to zone->dev_start to make sure all users have been converted. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0_make_request(): Replace local variable block by sector.Andre Noll2009-01-08
| | | | | | | This change already simplifies the code a bit. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0_make_request(): Remove local variable chunk_size.Andre Noll2009-01-08
| | | | | | | We might as well use chunk_sects instead. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: raid0_make_request(): Replace chunksize_bits by chunksect_bits.Andre Noll2009-01-08
| | | | | | | | | | | As ffz(~(2 * x)) = ffz(~x) + 1, we have chunksect_bits = chunksize_bits + 1. Fixup all users accordingly. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
* md: use sysfs_notify_dirent to notify changes to md/sync_action.NeilBrown2009-01-08
| | | | | | | There is no compelling need for this, but sysfs_notify_dirent is a nicer interface and the change is good for consistency. Signed-off-by: NeilBrown <neilb@suse.de>
* md: fix bitmap-on-external-file bug.NeilBrown2009-01-08
| | | | | | | | | | | commit a2ed9615e3222645007fc19991aedf30eed3ecfd fixed a bug with 'internal' bitmaps, but in the process broke 'in a file' bitmaps. So they are broken in 2.6.28 This fixes it, and needs to go in 2.6.28-stable. Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
* dm snapshot: extend exception store functionsJonathan Brassow2009-01-05
| | | | | | | | | Supply dm_add_exception as a callback to the read_metadata function. Add a status function ready for a later patch and name the functions consistently. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm snapshot: split out exception store implementationsAlasdair G Kergon2009-01-05
| | | | | | | | Move the existing snapshot exception store implementations out into separate files. Later patches will place these behind a new interface in preparation for alternative implementations. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm snapshot: rename struct exception_storeJonathan Brassow2009-01-05
| | | | | | | Rename struct exception_store to dm_exception_store. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm snapshot: separate out exception store interfaceJonathan Brassow2009-01-05
| | | | | | | | | | | | | Pull structures that bridge the gap between snapshot and exception store out of dm-snap.h and put them in a new .h file - dm-exception-store.h. This file will define the API for new exception stores. Ultimately, dm-snap.h is unnecessary, since only dm-snap.c should be using it. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: move trigger_event to system workqueueAlasdair G Kergon2009-01-05
| | | | | | | | | The same workqueue is used both for sending uevents and processing queued I/O. Deadlock has been reported in RHEL5 when sending a uevent was blocked waiting for the queued I/O to be processed. Use scheduled_work() for the asynchronous uevents instead. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add name and uuid to sysfsMilan Broz2009-01-05
| | | | | | | | | | | | | | | | | | | | | Implement simple read-only sysfs entry for device-mapper block device. This patch adds a simple sysfs directory named "dm" under block device properties and implements - name attribute (string containing mapped device name) - uuid attribute (string containing UUID, or empty string if not set) The kobject is embedded in mapped_device struct, so no additional memory allocation is needed for initializing sysfs entry. During the processing of sysfs attribute we need to lock mapped device which is done by a new function dm_get_from_kobj, which returns the md associated with kobject and increases the usage count. Each 'show attribute' function is responsible for its own locking. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: rework reference countingMikulas Patocka2009-01-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rework table reference counting. The existing code uses a reference counter. When the last reference is dropped and the counter reaches zero, the table destructor is called. Table reference counters are acquired/released from upcalls from other kernel code (dm_any_congested, dm_merge_bvec, dm_unplug_all). If the reference counter reaches zero in one of the upcalls, the table destructor is called from almost random kernel code. This leads to various problems: * dm_any_congested being called under a spinlock, which calls the destructor, which calls some sleeping function. * the destructor attempting to take a lock that is already taken by the same process. * stale reference from some other kernel code keeps the table constructed, which keeps some devices open, even after successful return from "dmsetup remove". This can confuse lvm and prevent closing of underlying devices or reusing device minor numbers. The patch changes reference counting so that the table destructor can be called only at predetermined places. The table has always exactly one reference from either mapped_device->map or hash_cell->new_map. After this patch, this reference is not counted in table->holders. A pair of dm_create_table/dm_destroy_table functions is used for table creation/destruction. Temporary references from the other code increase table->holders. A pair of dm_table_get/dm_table_put functions is used to manipulate it. When the table is about to be destroyed, we wait for table->holders to reach 0. Then, we call the table destructor. We use active waiting with msleep(1), because the situation happens rarely (to one user in 5 years) and removing the device isn't performance-critical task: the user doesn't care if it takes one tick more or not. This way, the destructor is called only at specific points (dm_table_destroy function) and the above problems associated with lazy destruction can't happen. Finally remove the temporary protection added to dm_any_congested(). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: support barriers on simple devicesAndi Kleen2009-01-05
| | | | | | | | | | | | | | | | | Implement barrier support for single device DM devices This patch implements barrier support in DM for the common case of dm linear just remapping a single underlying device. In this case we can safely pass the barrier through because there can be no reordering between devices. NB. Any DM device might cease to support barriers if it gets reconfigured so code must continue to allow for a possible -EOPNOTSUPP on every barrier bio submitted. - agk Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm request: add cachesKiyoshi Ueda2009-01-05
| | | | | | | | This patch prepares some kmem_caches for request-based dm. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm ioctl: allow dm_copy_name_and_uuid to return only one fieldMilan Broz2009-01-05
| | | | | | | | | | | Allow NULL buffer in dm_copy_name_and_uuid if you only want to return one of the fields. (Required by a following patch that adds these fields to sysfs.) Signed-off-by: Milan Broz <mbroz@redhat.com> Reviewed-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm log: ensure log bitmap fits on log deviceMilan Broz2009-01-05
| | | | | | | Check that the log bitmap will fit within the log device. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm log: move region_size validationMilan Broz2009-01-05
| | | | | | | | | Move log size validation from mirror target to log constructor. Removed PAGE_SIZE restriction we no longer think necessary. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm log: avoid reinitialising io_req on every operationTakahiro Yasui2009-01-05
| | | | | | | | | | | | | rw_header function updates three members of io_req data every time when I/O is processed. bi_rw and notify.fn are never modified once they get initialized, and so they can be set in advance. header_to_disk() can also be pulled out of write_header() since only one caller needs it and write_header() can be replaced by rw_header() directly. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: consolidate target deregistration error handlingMikulas Patocka2009-01-05
| | | | | | | | | | | | | | | | | | | | Change dm_unregister_target to return void and use BUG() for error reporting. dm_unregister_target can only fail because of programming bug in the target driver. It can't fail because of user's behavior or disk errors. This patch changes unregister_target to return void and use BUG if someone tries to unregister non-registered target or unregister target that is in use. This patch removes code duplication (testing of error codes in all dm targets) and reports bugs in just one place, in dm_unregister_target. In some target drivers, these return codes were ignored, which could lead to a situation where bugs could be missed. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm raid1: fix error countJonathan Brassow2009-01-05
| | | | | | | | | | | | | | | | | Always increase the error count when I/O on a leg of a mirror fails. The error count is used to decide whether to select an alternative mirror leg. If the target doesn't use the "handle_errors" feature, the error count is not updated and the bio can get requeued forever by the read callback. Fix it by increasing error_count before the handle_errors feature checking. Cc: stable@kernel.org Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm log: fix dm_io_client leak on error pathsTakahiro Yasui2009-01-05
| | | | | | | | | | | In create_log_context function, dm_io_client_destroy function needs to be called, when memory allocation of disk_header, sync_bits and recovering_bits failed, but dm_io_client_destroy is not called. Cc: stable@kernel.org Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Acked-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm snapshot: change yield to msleepMikulas Patocka2009-01-05
| | | | | | | | | Change yield() to msleep(1). If the thread had realtime priority, yield() doesn't really yield, so the yielding process would loop indefinitely and cause machine lockup. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm table: drop reference at unbindMikulas Patocka2009-01-05
| | | | | | | | | | | | | Move one dm_table_put() so that the last reference in the thread gets dropped in __unbind(). This is required for a following patch, dm-table-rework-reference-counting.patch, which will change the logic in such a way that table destructor is called only at specific points in the code. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* bio: allow individual slabs in the bio_setJens Axboe2008-12-29
| | | | | | | | | | | | | | | Instead of having a global bio slab cache, add a reference to one in each bio_set that is created. This allows for personalized slabs in each bio_set, so that they can have bios of different sizes. This means we can personalize the bios we return. File systems may want to embed the bio inside another structure, to avoid allocation more items (and stuffing them in ->bi_private) after the get a bio. Or we may want to embed a number of bio_vecs directly at the end of a bio, to avoid doing two allocations to return a bio. This is now possible. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Merge branch 'linus' into tracing/hw-branch-tracingIngo Molnar2008-12-24
|\
| * md: Don't read past end of bitmap when reading bitmap.NeilBrown2008-12-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we read the write-intent-bitmap off the device, we currently read a whole number of pages. When PAGE_SIZE is 4K, this works due to the alignment we enforce on the superblock and bitmap. When PAGE_SIZE is 64K, this case read past the end-of-device which causes an error. When we write the superblock, we ensure to clip the last page to just be the required size. Copy that code into the read path to just read the required number of sectors. Signed-off-by: Neil Brown <neilb@suse.de> Cc: stable@kernel.org
* | Merge branches 'tracing/ftrace', 'tracing/function-graph-tracer' and ↵Ingo Molnar2008-12-05
|\| | | | | | | 'tracing/urgent' into tracing/core
| * block: fix setting of max_segment_size and seg_boundary maskMilan Broz2008-12-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix setting of max_segment_size and seg_boundary mask for stacked md/dm devices. When stacking devices (LVM over MD over SCSI) some of the request queue parameters are not set up correctly in some cases by default, namely max_segment_size and and seg_boundary mask. If you create MD device over SCSI, these attributes are zeroed. Problem become when there is over this mapping next device-mapper mapping - queue attributes are set in DM this way: request_queue max_segment_size seg_boundary_mask SCSI 65536 0xffffffff MD RAID1 0 0 LVM 65536 -1 (64bit) Unfortunately bio_add_page (resp. bio_phys_segments) calculates number of physical segments according to these parameters. During the generic_make_request() is segment cout recalculated and can increase bio->bi_phys_segments count over the allowed limit. (After bio_clone() in stack operation.) Thi is specially problem in CCISS driver, where it produce OOPS here BUG_ON(creq->nr_phys_segments > MAXSGENTRIES); (MAXSEGENTRIES is 31 by default.) Sometimes even this command is enough to cause oops: dd iflag=direct if=/dev/<vg>/<lv> of=/dev/null bs=128000 count=10 This command generates bios with 250 sectors, allocated in 32 4k-pages (last page uses only 1024 bytes). For LVM layer, it allocates bio with 31 segments (still OK for CCISS), unfortunatelly on lower layer it is recalculated to 32 segments and this violates CCISS restriction and triggers BUG_ON(). The patch tries to fix it by: * initializing attributes above in queue request constructor blk_queue_make_request() * make sure that blk_queue_stack_limits() inherits setting (DM uses its own function to set the limits because it blk_queue_stack_limits() was introduced later. It should probably switch to use generic stack limit function too.) * sets the default seg_boundary value in one place (blkdev.h) * use this mask as default in DM (instead of -1, which differs in 64bit) Bugs related to this: https://bugzilla.redhat.com/show_bug.cgi?id=471639 http://bugzilla.kernel.org/show_bug.cgi?id=8672 Signed-off-by: Milan Broz <mbroz@redhat.com> Reviewed-by: Alasdair G Kergon <agk@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Mike Miller <mike.miller@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | blktrace: port to tracepoints, updateIngo Molnar2008-11-26
| | | | | | | | | | | | | | | | | | Port to the new tracepoints API: split DEFINE_TRACE() and DECLARE_TRACE() sites. Spread them out to the usage sites, as suggested by Mathieu Desnoyers. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
* | blktrace: port to tracepointsArnaldo Carvalho de Melo2008-11-26
|/ | | | | | | | | | | This was a forward port of work done by Mathieu Desnoyers, I changed it to encode the 'what' parameter on the tracepoint name, so that one can register interest in specific events and not on classes of events to then check the 'what' parameter. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dm: avoid destroying table in dm_any_congestedChandra Seetharaman2008-11-13
| | | | | | | | | | | | | | | | | | | | | dm_any_congested() just checks for the DMF_BLOCK_IO and has no code to make sure that suspend waits for dm_any_congested() to complete. This patch adds such a check. Without it, a race can occur with dm_table_put() attempting to destroying the table in the wrong thread, the one running dm_any_congested() which is meant to be quick and return immediately. Two examples of problems: 1. Sleeping functions called from congested code, the caller of which holds a spin lock. 2. An ABBA deadlock between pdflush and multipathd. The two locks in contention are inode lock and kernel lock. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: move pending queue wake_up end_io_acctMikulas Patocka2008-11-13
| | | | | | | | | | | | This doesn't fix any bug, just moves wake_up immediately after decrementing md->pending, for better code readability. It must be clear to anyone manipulating md->pending to wake up the queue if md->pending reaches zero, so move the wakeup as close to the decrementing as possible. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: warn if args ignoredChandra Seetharaman2008-11-13
| | | | | | | | | | | Currently dm ignores the parameters provided to hardware handlers without providing any notifications to the user. This patch just prints a warning message so that the user knows that the arguments are ignored. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: avoid attempting to activate null pathChandra Seetharaman2008-11-13
| | | | | | | | | | | Path activation code is called even when the pgpath is NULL. This could lead to a panic in activate_path(). Such a panic is seen in -rt kernel. This problem has been there before the pg_init() was moved to a workqueue. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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