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2010-02-16dm: sysfs revert add empty release function to avoid debug warningAlasdair G Kergon
Revert commit d2bb7df8cac647b92f51fb84ae735771e7adbfa7 at Greg's request. Author: Milan Broz <mbroz@redhat.com> Date: Thu Dec 10 23:51:53 2009 +0000 dm: sysfs add empty release function to avoid debug warning This patch just removes an unnecessary warning: kobject: 'dm': does not have a release() function, it is broken and must be fixed. The kobject is embedded in mapped device struct, so code does not need to release memory explicitly here. Cc: Greg KH <gregkh@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm mpath: fix stall when requeueing ioKiyoshi Ueda
This patch fixes the problem that system may stall if target's ->map_rq returns DM_MAPIO_REQUEUE in map_request(). E.g. stall happens on 1 CPU box when a dm-mpath device with queue_if_no_path bounces between all-paths-down and paths-up on I/O load. When target's ->map_rq returns DM_MAPIO_REQUEUE, map_request() requeues the request and returns to dm_request_fn(). Then, dm_request_fn() doesn't exit the I/O dispatching loop and continues processing the requeued request again. This map and requeue loop can be done with interrupt disabled, so 1 CPU system can be stalled if this situation happens. For example, commands below can stall my 1 CPU box within 1 minute or so: # dmsetup table mp mp: 0 2097152 multipath 1 queue_if_no_path 0 1 1 service-time 0 1 2 8:144 1 1 # while true; do dd if=/dev/mapper/mp of=/dev/null bs=1M count=100; done & # while true; do \ > dmsetup message mp 0 "fail_path 8:144" \ > dmsetup suspend --noflush mp \ > dmsetup resume mp \ > dmsetup message mp 0 "reinstate_path 8:144" \ > done To fix the problem above, this patch changes dm_request_fn() to exit the I/O dispatching loop once if a request is requeued in map_request(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm raid1: fix null pointer dereference in suspendTakahiro Yasui
When suspending a failed mirror, bios are completed by mirror_end_io() and __rh_lookup() in dm_rh_dec() returns NULL where a non-NULL return value is required by design. Fix this by not changing the state of the recovery failed region from DM_RH_RECOVERING to DM_RH_NOSYNC in dm_rh_recovery_end(). Issue On 2.6.33-rc1 kernel, I hit the bug when I suspended the failed mirror by dmsetup command. BUG: unable to handle kernel NULL pointer dereference at 00000020 IP: [<f94f38e2>] dm_rh_dec+0x35/0xa1 [dm_region_hash] ... EIP: 0060:[<f94f38e2>] EFLAGS: 00010046 CPU: 0 EIP is at dm_rh_dec+0x35/0xa1 [dm_region_hash] EAX: 00000286 EBX: 00000000 ECX: 00000286 EDX: 00000000 ESI: eff79eac EDI: eff79e80 EBP: f6915cd4 ESP: f6915cc4 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process dmsetup (pid: 2849, ti=f6914000 task=eff03e80 task.ti=f6914000) ... Call Trace: [<f9530af6>] ? mirror_end_io+0x53/0x1b1 [dm_mirror] [<f9413104>] ? clone_endio+0x4d/0xa2 [dm_mod] [<f9530aa3>] ? mirror_end_io+0x0/0x1b1 [dm_mirror] [<f94130b7>] ? clone_endio+0x0/0xa2 [dm_mod] [<c02d6bcb>] ? bio_endio+0x28/0x2b [<f952f303>] ? hold_bio+0x2d/0x62 [dm_mirror] [<f952f942>] ? mirror_presuspend+0xeb/0xf7 [dm_mirror] [<c02aa3e2>] ? vmap_page_range+0xb/0xd [<f9414c8d>] ? suspend_targets+0x2d/0x3b [dm_mod] [<f9414ca9>] ? dm_table_presuspend_targets+0xe/0x10 [dm_mod] [<f941456f>] ? dm_suspend+0x4d/0x150 [dm_mod] [<f941767d>] ? dev_suspend+0x55/0x18a [dm_mod] [<c0343762>] ? _copy_from_user+0x42/0x56 [<f9417fb0>] ? dm_ctl_ioctl+0x22c/0x281 [dm_mod] [<f9417628>] ? dev_suspend+0x0/0x18a [dm_mod] [<f9417d84>] ? dm_ctl_ioctl+0x0/0x281 [dm_mod] [<c02c3c4b>] ? vfs_ioctl+0x22/0x85 [<c02c422c>] ? do_vfs_ioctl+0x4cb/0x516 [<c02c42b7>] ? sys_ioctl+0x40/0x5a [<c0202858>] ? sysenter_do_call+0x12/0x28 Analysis When recovery process of a region failed, dm_rh_recovery_end() function changes the state of the region from RM_RH_RECOVERING to DM_RH_NOSYNC. When recovery_complete() is executed between dm_rh_update_states() and dm_writes() in do_mirror(), bios are processed with the region state, DM_RH_NOSYNC. However, the region data is freed without checking its pending count when dm_rh_update_states() is called next time. When bios are finished by mirror_end_io(), __rh_lookup() in dm_rh_dec() returns NULL even though a valid return value are expected. Solution Remove the state change of the recovery failed region from DM_RH_RECOVERING to DM_RH_NOSYNC in dm_rh_recovery_end(). We can remove the state change because: - If the region data has been released by dm_rh_update_states(), a new region data is created with the state of DM_RH_NOSYNC, and bios are processed according to the DM_RH_NOSYNC state. - If the region data has not been released by dm_rh_update_states(), a state of the region is DM_RH_RECOVERING and bios are put in the delayed_bio list. The flag change from DM_RH_RECOVERING to DM_RH_NOSYNC in dm_rh_recovery_end() was added in the following commit: dm raid1: handle resync failures author Jonathan Brassow <jbrassow@redhat.com> Thu, 12 Jul 2007 16:29:04 +0000 (17:29 +0100) http://git.kernel.org/linus/f44db678edcc6f4c2779ac43f63f0b9dfa28b724 Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm raid1: fail writes if errors are not handled and log failsMikulas Patocka
If the mirror log fails when the handle_errors option was not selected and there is no remaining valid mirror leg, writes return success even though they weren't actually written to any device. This patch completes them with EIO instead. This code path is taken: do_writes: bio_list_merge(&ms->failures, &sync); do_failures: if (!get_valid_mirror(ms)) (false) else if (errors_handled(ms)) (false) else bio_endio(bio, 0); The logic in do_failures is based on presuming that the write was already tried: if it succeeded at least on one leg (without handle_errors) it is reported as success. Reference: https://bugzilla.redhat.com/show_bug.cgi?id=555197 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm log: userspace fix overhead_size calcuationsJonathan Brassow
This patch fixes two bugs that revolve around the miscalculation and misuse of the variable 'overhead_size'. 'overhead_size' is the size of the various header structures used during communication. The first bug is the use of 'sizeof' with the pointer of a structure instead of the structure itself - resulting in the wrong size being computed. This is then used in a check to see if the payload (data_size) would be to large for the preallocated structure. Since the bug produces a smaller value for the overhead, it was possible for the structure to be breached. (Although the current users of the code do not currently send enough data to trigger this bug.) The second bug is that the 'overhead_size' value is used to compute how much of the preallocated space should be cleared before populating it with fresh data. This should have simply been 'sizeof(struct cn_msg)' not overhead_size. The fact that 'overhead_size' was computed incorrectly made this problem "less bad" - leaving only a pointer's worth of space at the end uncleared. Thus, this bug was never producing a bad result, but still needs to be fixed - especially now that the value is computed correctly. Cc: stable@kernel.org Signed-off-by: Jonathan Brassow <jbrassow@redhat.com Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm snapshot: persistent annotate work_queue as on stackMike Snitzer
chunk_io() declares its 'struct mdata_req' on the stack and then initializes its 'struct work_struct' member. Annotate the initialization of this workqueue with INIT_WORK_ON_STACK to suppress a debugobjects warning seen when CONFIG_DEBUG_OBJECTS_WORK is enabled. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm stripe: avoid divide by zero with invalid stripe countNikanth Karthikesan
If a table containing zero as stripe count is passed into stripe_ctr the code attempts to divide by zero. This patch changes DM_TABLE_LOAD to return -EINVAL if the stripe count is zero. We now get the following error messages: device-mapper: table: 253:0: striped: Invalid stripe count device-mapper: ioctl: error adding target to table Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-10md: fix some lockdep issues between md and sysfs.NeilBrown
====== This fix is related to http://bugzilla.kernel.org/show_bug.cgi?id=15142 but does not address that exact issue. ====== sysfs does like attributes being removed while they are being accessed (i.e. read or written) and waits for the access to complete. As accessing some md attributes takes the same lock that is held while removing those attributes a deadlock can occur. This patch addresses 3 issues in md that could lead to this deadlock. Two relate to calling flush_scheduled_work while the lock is held. This is probably a bad idea in general and as we use schedule_work to delete various sysfs objects it is particularly bad. In one case flush_scheduled_work is called from md_alloc (called by md_probe) called from do_md_run which holds the lock. This call is only present to ensure that ->gendisk is set. However we can be sure that gendisk is always set (though possibly we couldn't when that code was originally written. This is because do_md_run is called in three different contexts: 1/ from md_ioctl. This requires that md_open has succeeded, and it fails if ->gendisk is not set. 2/ from writing a sysfs attribute. This can only happen if the mddev has been registered in sysfs which happens in md_alloc after ->gendisk has been set. 3/ from autorun_array which is only called by autorun_devices, which checks for ->gendisk to be set before calling autorun_array. So the call to md_probe in do_md_run can be removed, and the check on ->gendisk can also go. In the other case flush_scheduled_work is being called in do_md_stop, purportedly to wait for all md_delayed_delete calls (which delete the component rdevs) to complete. However there really isn't any need to wait for them - they have already been disconnected in all important ways. The third issue is that raid5->stop() removes some attribute names while the lock is held. There is already some infrastructure in place to delay attribute removal until after the lock is released (using schedule_work). So extend that infrastructure to remove the raid5_attrs_group. This does not address all lockdep issues related to the sysfs "s_active" lock. The rest can be address by splitting that lockdep context between symlinks and non-symlinks which hopefully will happen. Signed-off-by: NeilBrown <neilb@suse.de>
2010-02-09md: fix 'degraded' calculation when starting a reshape.NeilBrown
This code was written long ago when it was not possible to reshape a degraded array. Now it is so the current level of degraded-ness needs to be taken in to account. Also newly addded devices should only reduce degradedness if they are deemed to be in-sync. In particular, if you convert a RAID5 to a RAID6, and increase the number of devices at the same time, then the 5->6 conversion will make the array degraded so the current code will produce a wrong value for 'degraded' - "-1" to be precise. If the reshape runs to completion end_reshape will calculate a correct new value for 'degraded', but if a device fails during the reshape an incorrect decision might be made based on the incorrect value of "degraded". This patch is suitable for 2.6.32-stable and if they are still open, 2.6.31-stable and 2.6.30-stable as well. Cc: stable@kernel.org Reported-by: Michael Evans <mjevans1983@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
2010-01-11DM: Fix device mapper topology stackingMartin K. Petersen
Make DM use bdev_stack_limits() function so that partition offsets get taken into account when calculating alignment. Clarify stacking warnings. Also remove obsolete clearing of final alignment_offset and misalignment flag. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair G. Kergon <agk@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-30md: allow a resync that is waiting for other resync to complete, to be aborted.NeilBrown
If two arrays share a device, then they will not both resync at the same time. One will wait for the other to complete. While waiting, the MD_RECOVERY_INTR flag is not checked so a device failure, which would make the resync pointless, does not cause the resync to abort, so the failed device cannot be removed (as it cannot be remove while a resync is happening). So add a test for MD_RECOVERY_INTR. Reported-by: Brett Russ <bruss@netezza.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-30md: remove unnecessary code from do_md_runNeilBrown
Since commit dfc7064500061677720fa26352963c772d3ebe6b, ->hot_remove_disks has not removed non-failed devices from an array until recovery is no longer possible. So the code in do_md_run to get around the fact that md_check_recovery (which calls ->hot_remove_disks) would remove partially-in-sync devices is no longer needed. So remove it. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-30md: make recovery started by do_md_run() visible via sync_actionDan Williams
By default md_do_sync() will perform recovery if no other actions are specified. However, action_show() relies on MD_RECOVERY_RECOVER to be set otherwise it returns 'idle'. So, add a missing set MD_RECOVERY_RECOVER when starting recovery. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-30md: fix small irregularity with start_ro module parameterNeilBrown
The start_ro modules parameter can be used to force arrays to be started in 'auto-readonly' in which they are read-only until the first write. This ensures that no resync/recovery happens until something else writes to the device. This is important for resume-from-disk off an md array. However if an array is started 'readonly' (by writing 'readonly' to the 'array_state' sysfs attribute) we want it to be really 'readonly', not 'auto-readonly'. So strengthen the condition to only set auto-readonly if the array is not already read-only. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-30md: Fix unfortunate interaction with evmsNeilBrown
evms configures md arrays by: open device send ioctl close device for each different ioctl needed. Since 2.6.29, the device can disappear after the 'close' unless a significant configuration has happened to the device. The change made by "SET_ARRAY_INFO" can too minor to stop the device from disappearing, but important enough that losing the change is bad. So: make sure SET_ARRAY_INFO sets mddev->ctime, and keep the device active as long as ctime is non-zero (it gets zeroed with lots of other things when the array is stopped). This is suitable for -stable kernels since 2.6.29. Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
2009-12-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dmLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (80 commits) dm snapshot: use merge origin if snapshot invalid dm snapshot: report merge failure in status dm snapshot: merge consecutive chunks together dm snapshot: trigger exceptions in remaining snapshots during merge dm snapshot: delay merging a chunk until writes to it complete dm snapshot: queue writes to chunks being merged dm snapshot: add merging dm snapshot: permit only one merge at once dm snapshot: support barriers in snapshot merge target dm snapshot: avoid allocating exceptions in merge dm snapshot: rework writing to origin dm snapshot: add merge target dm exception store: add merge specific methods dm snapshot: create function for chunk_is_tracked wait dm snapshot: make bio optional in __origin_write dm mpath: reject messages when device is suspended dm: export suspended state to targets dm: rename dm_suspended to dm_suspended_md dm: swap target postsuspend call and setting suspended flag dm crypt: add plain64 iv ...
2009-12-15drivers/md/md.c: use %pU to print UUIDsJoe Perches
Signed-off-by: Joe Perches <joe@perches.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15tree-wide: convert open calls to remove spaces to skip_spaces() lib functionAndré Goddard Rosa
Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-14md: add 'recovery_start' per-device sysfs attributeDan Williams
Enable external metadata arrays to manage rebuild checkpointing via a md/dev-XXX/recovery_start attribute which reflects rdev->recovery_offset Also update resync_start_store to allow 'none' to be written, for consistency. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: rcu_read_lock() walk of mddev->disks in md_do_sync()Dan Williams
Other walks of this list are either under rcu_read_lock() or the list mutation lock (mddev_lock()). This protects against the improbable case of a disk being removed from the array at the start of md_do_sync(). Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-12-14md: integrate spares into array at earliest opportunity.NeilBrown
As v1.x metadata can record that a member of the array is not completely recovered, it make sense to record that a spare has become a regular member of the array at the earliest opportunity. So remove the tests on "recovery_offset > 0" in super_1_sync as they really aren't needed, and schedule a metadata update immediately after adding spares to a degraded array. This means that if a crash happens immediately after a recovery starts, the new device will be included in the array and recovery will continue from wherever it was up to. Previously this didn't happen unless recovery was at least 1/16 of the way through. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: move compat_ioctl handling into md.cArnd Bergmann
The RAID ioctls are only implemented in md.c, so the handling for them should also be moved there from fs/compat_ioctl.c. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Neil Brown <neilb@suse.de> Cc: Andre Noll <maan@systemlinux.org> Cc: linux-raid@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: revise Kconfig help for MD_MULTIPATHNeilBrown
Make it clear in the config message that MD_MULTIPATH is not under active development. Cc: Oren Held <orenhe@il.ibm.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: add MODULE_DESCRIPTION for all md related modules.NeilBrown
Suggested by Oren Held <orenhe@il.ibm.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14raid: improve MD/raid10 handling of correctable read errors.Robert Becker
We've noticed severe lasting performance degradation of our raid arrays when we have drives that yield large amounts of media errors. The raid10 module will queue each failed read for retry, and also will attempt call fix_read_error() to perform the read recovery. Read recovery is performed while the array is frozen, so repeated recovery attempts can degrade the performance of the array for extended periods of time. With this patch I propose adding a per md device max number of corrected read attempts. Each rdev will maintain a count of read correction attempts in the rdev->read_errors field (not used currently for raid10). When we enter fix_read_error() we'll check to see when the last read error occurred, and divide the read error count by 2 for every hour since the last read error. If at that point our read error count exceeds the read error threshold, we'll fail the raid device. In addition in this patch I add sysfs nodes (get/set) for the per md max_read_errors attribute, the rdev->read_errors attribute, and added some printk's to indicate when fix_read_error fails to repair an rdev. For testing I used debugfs->fail_make_request to inject IO errors to the rdev while doing IO to the raid array. Signed-off-by: Robert Becker <Rob.Becker@riverbed.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/raid10: print more useful messages on device failure.Robert Becker
When we get a read error on a device in a RAID10, and attempting to repair the error fails, print more useful messages about why it failed. Signed-off-by: Robert Becker <Rob.Becker@riverbed.com> Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/bitmap: update dirty flag when bitmap bits are explicitly set.NeilBrown
There is a sysfs file which allows bits in the write-intent bitmap to be explicit set - indicating that the block is thought to be 'dirty'. When this happens we should really set recovery_cp backwards to include the block to reflect this dirtiness. In particular, a 'resync' process will refuse to start if recovery_cp is beyond the end of the array, so this is needed to allow a resync to be triggered. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: Support write-intent bitmaps with externally managed metadata.NeilBrown
In this case, the metadata needs to not be in the same sector as the bitmap. md will not read/write any bitmap metadata. Config must be done via sysfs and when a recovery makes the array non-degraded again, writing 'true' to 'bitmap/can_clear' will allow bits in the bitmap to be cleared again. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/bitmap: move setting of daemon_lastrun out of bitmap_read_sbNeilBrown
Setting daemon_lastrun really has nothing to do with reading the bitmap superblock, it just happens to be needed at the same time. bitmap_read_sb is about to become options, so move that code out to after the call to bitmap_read_sb. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: support updating bitmap parameters via sysfs.NeilBrown
A new attribute directory 'bitmap' in 'md' is created which contains files for configuring the bitmap. 'location' identifies where the bitmap is, either 'none', or 'file' or 'sector offset from metadata'. Writing 'location' can create or remove a bitmap. Adding a 'file' bitmap this way is not yet supported. 'chunksize' and 'time_base' must be set before 'location' can be set. 'chunksize' can be set before creating a bitmap, but is currently always over-ridden by the bitmap superblock. 'time_base' and 'backlog' can be updated at any time. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Andre Noll <maan@systemlinux.org>
2009-12-14md: factor out parsing of fixed-point numbersNeilBrown
safe_delay_store can parse fixed point numbers (for fractions of a second). We will want to do that for another sysfs file soon, so factor out the code. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: support bitmap offset appropriate for external-metadata arrays.NeilBrown
For md arrays were metadata is managed externally, the kernel does not know about a superblock so the superblock offset is 0. If we want to have a write-intent-bitmap near the end of the devices of such an array, we should support sector_t sized offset. We need offset be possibly negative for when the bitmap is before the metadata, so use loff_t instead. Also add sanity check that bitmap does not overlap with data. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: remove needless setting of thread->timeout in raid10_quiesceNeilBrown
As bitmap_create and bitmap_destroy already set thread->timeout as appropriate, there is no need to do it in raid10_quiesce. There is a possible need to wake the thread after the timeout has been set low, but it is better to do that where the timeout is actually set low, in bitmap_create. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: change daemon_sleep to be in 'jiffies' rather than 'seconds'.NeilBrown
This removes a lot of multiplications by HZ. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: move offset, daemon_sleep and chunksize out of bitmap structureNeilBrown
... and into bitmap_info. These are all configuration parameters that need to be set before the bitmap is created. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: collect bitmap-specific fields into one structure.NeilBrown
In preparation for making bitmap fields configurable via sysfs, start tidying up by making a single structure to contain the configuration fields. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/raid1: add takeover support for raid5->raid1NeilBrown
A 2-device raid5 array can now be converted to raid1. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: add honouring of suspend_{lo,hi} to raid1.NeilBrown
This will allow us to stop writeout to portions of the array while they are resynced by someone else - e.g. another node in a cluster. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/raid5: don't complete make_request on barrier until writes are scheduledNeilBrown
The post-barrier-flush is sent by md as soon as make_request on the barrier write completes. For raid5, the data might not be in the per-device queues yet. So for barrier requests, wait for any pre-reading to be done so that the request will be in the per-device queues. We use the 'preread_active' count to check that nothing is still in the preread phase, and delay the decrement of this count until after write requests have been submitted to the underlying devices. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: support barrier requests on all personalities.NeilBrown
Previously barriers were only supported on RAID1. This is because other levels requires synchronisation across all devices and so needed a different approach. Here is that approach. When a barrier arrives, we send a zero-length barrier to every active device. When that completes - and if the original request was not empty - we submit the barrier request itself (with the barrier flag cleared) and then submit a fresh load of zero length barriers. The barrier request itself is asynchronous, but any subsequent request will block until the barrier completes. The reason for clearing the barrier flag is that a barrier request is allowed to fail. If we pass a non-empty barrier through a striping raid level it is conceivable that part of it could succeed and part could fail. That would be way too hard to deal with. So if the first run of zero length barriers succeed, we assume all is sufficiently well that we send the request and ignore errors in the second run of barriers. RAID5 needs extra care as write requests may not have been submitted to the underlying devices yet. So we flush the stripe cache before proceeding with the barrier. Note that the second set of zero-length barriers are submitted immediately after the original request is submitted. Thus when a personality finds mddev->barrier to be set during make_request, it should not return from make_request until the corresponding per-device request(s) have been queued. That will be done in later patches. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Andre Noll <maan@systemlinux.org>
2009-12-14md: don't reset curr_resync_completed after an interrupted resyncNeilBrown
If a resync/recovery/check/repair is interrupted for some reason, it can be useful to know exactly where it got up to. So in that case, do not clear curr_resync_completed. Initialise it when starting a resync/recovery/... instead. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: adjust resync_min usefully when resync aborts.NeilBrown
When a 'check' or 'repair' finished we should clear resync_min so that a future check/repair will cover the whole array (by default). However if it is interrupted, we should update resync_min to where we got up to, so that when the check/repair continues it just does the remainder of the array. Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md: remove sparse warning:symbol XXX was not declared.NeilBrown
Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/raid5: remove some sparse warnings.NeilBrown
qd_idx is previously declared and given exactly the same value! Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14md/bitmap: protect against bitmap removal while being updated.NeilBrown
A write intent bitmap can be removed from an array while the array is active. When this happens, all IO is suspended and flushed before the bitmap is removed. However it is possible that bitmap_daemon_work is still running to clear old bits from the bitmap. If it is, it can dereference the bitmap after it has been freed. So introduce a new mutex to protect bitmap_daemon_work and get it before destroying a bitmap. This is suitable for any current -stable kernel. Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
2009-12-10dm snapshot: use merge origin if snapshot invalidMikulas Patocka
If the snapshot we are merging became invalid (e.g. it ran out of space) redirect all I/O directly to the origin device. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: report merge failure in statusMike Snitzer
Set 'merge_failed' flag if a snapshot fails to merge. Update snapshot_status() to report "Merge failed" if 'merge_failed' is set. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: merge consecutive chunks togetherMike Snitzer
s->store->type->prepare_merge returns the number of chunks that can be copied linearly working backwards from the returned chunk number. For example, if it returns 3 chunks with old_chunk == 10 and new_chunk == 20, then chunk 20 can be copied to 10, chunk 19 to 9 and 18 to 8. Until now kcopyd only copied one chunk at a time. This patch now copies the full set at once. Consequently, snapshot_merge_process() needs to delay the merging of all chunks if any have writes in progress, not just the first chunk in the region that is to be merged. snapshot-merge's performance is now comparable to the original snapshot-origin target. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: trigger exceptions in remaining snapshots during mergeMikulas Patocka
When there is one merging snapshot and other non-merging snapshots, snapshot_merge_process() must make exceptions in the non-merging snapshots. Use a sequence count to resolve the race between I/O to chunks that are about to be merged. The count increases each time an exception reallocation finishes. Use wait_event() to wait until the count changes. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: delay merging a chunk until writes to it completeMikulas Patocka
Track writes to chunks that are currently being merged and delay merging a chunk until all writes to that chunk finish. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>