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* [PATCH] Add block_device_operations.getgeo block device methodChristoph Hellwig2006-01-081-19/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | HDIO_GETGEO is implemented in most block drivers, and all of them have to duplicate the code to copy the structure to userspace, as well as getting the start sector. This patch moves that to common code [1] and adds a ->getgeo method to fill out the raw kernel hd_geometry structure. For many drivers this means ->ioctl can go away now. [1] the s390 block drivers are odd in this respect. xpram sets ->start to 4 always which seems more than odd, and the dasd driver shifts the start offset around, probably because of it's non-standard sector size. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Jens Axboe <axboe@suse.de> Cc: <mike.miller@hp.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow sync-speed to be controlled per-deviceNeilBrown2006-01-061-5/+105
| | | | | | | | | Also export current (average) speed and status in sysfs. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: support adding new devices to md arrays via sysfsNeilBrown2006-01-061-0/+60
| | | | | | | | | Writing major:minor to md/new_dev will bind that device to the array. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow available size of component devices to be set via sysfsNeilBrown2006-01-061-0/+25
| | | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md-export-rdev-data_offset-via-sysfs-fixAndrew Morton2006-01-061-1/+1
| | | | | | | | | drivers/md/md.c: In function `offset_show': drivers/md/md.c:1670: warning: long long unsigned int format, different type arg (arg 3) Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: export rdev->data_offset via sysfsNeilBrown2006-01-061-0/+23
| | | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: expose device slot information via sysfsNeilBrown2006-01-061-0/+35
| | | | | | | | | This the role that a device has in an array can be viewed and set. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: keep better track of dev/array size when assembling md arraysNeilBrown2006-01-061-18/+23
| | | | | | | | | | | | | Move the checks - that dev size is never less than array size - into bind_rdev_to_array to make sure it always happens properly (there is one place where currently it doesn't). Also reject any superblock which claims an array size smaller than the device in question can hold. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow md/raid_disks to be settableNeilBrown2006-01-061-23/+51
| | | | | | | | | If array is active, try to reshape, else just set the value. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: count corrected read errors per driveNeilBrown2006-01-065-4/+42
| | | | | | | | | | Store this total in superblock (As appropriate), and make it available to userspace via sysfs. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow array level to be set textually via sysfsNeilBrown2006-01-069-14/+58
| | | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: expose md metadata format in sysfsNeilBrown2006-01-061-0/+49
| | | | | | | | | Allow it to be set to a particular version, or 'none'. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow md array component size to be accessed and set via sysfsNeilBrown2006-01-061-42/+89
| | | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow chunk_size to be settable through sysfsNeilBrown2006-01-061-0/+26
| | | | | | | | | ... only before array is started of course. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix rdev->pending counts in raid1NeilBrown2006-01-062-11/+10
| | | | | | | | | | | | | When we do a user-requested check/repair, we lose count of the outstanding requests... Also make sure that when anything is written to md/sync_action, the RECOVERY_NEEDED flag is set and the thread is woken up so any changes take effect. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: make sure bitmap updates are visible through filesystemNeilBrown2006-01-061-0/+2
| | | | | | | | | When we update a page_cache page in the kernel, we need to flush_dache_page or userspace might not see the change. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] drivers/md/md.c: make md_new_event() staticAdrian Bunk2006-01-061-1/+1
| | | | | | | | | Make the needlessly global function md_new_event() static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: make a couple of names in md.c staticNeilBrown2006-01-061-2/+2
| | | | | | | | .. because they aren't used outside md.c Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix typo in commentNeilBrown2006-01-061-1/+1
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: helper function to match commands written to sysfs filesNeilBrown2006-01-061-5/+24
| | | | | | | | | | Commands written to sysfs files may, or my not, be \n terminated. We want to accept with case. For this we use cmd_match. Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: define and use safe_put_page for mdNeilBrown2006-01-064-12/+10
| | | | | | | | | md sometimes call put_page on NULL pointers (treating it like kfree). This is not safe, so define and use a 'safe_put_page' which checks for NULL. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: remove inappropriate limits in md/bitmap configuration.NeilBrown2006-01-061-4/+4
| | | | | | | | | | | The kernel should not be imposing these policy limits: The time between bitmap updates should certainly be allowed to be more than 15 seconds, and if someone wants a bitmap chunk size in excess of 4MB, the kernel isn't the place to stop them. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix possible problem in raid1/raid10 error overwritingNeilBrown2006-01-062-12/+48
| | | | | | | | | | | | | | The code to overwrite/reread for addressing read errors in raid1/raid10 currently assumes that the read will not alter the buffer which could be used to write to the next device. This is not a safe assumption to make. So we split the loops into a overwrite loop and a separate re-read loop, so that the writing is complete before reading is attempted. Cc: Paul Clements <paul.clements@steeleye.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: remove personality numbering from mdNeilBrown2006-01-069-87/+104
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md supports multiple different RAID level, each being implemented by a 'personality' (which is often in a separate module). These personalities have fairly artificial 'numbers'. The numbers are use to: 1- provide an index into an array where the various personalities are recorded 2- identify the module (via an alias) which implements are particular personality. Neither of these uses really justify the existence of personality numbers. The array can be replaced by a linked list which is searched (array lookup only happens very rarely). Module identification can be done using an alias based on level rather than 'personality' number. The current 'raid5' modules support two level (4 and 5) but only one personality. This slight awkwardness (which was handled in the mapping from level to personality) can be better handled by allowing raid5 to register 2 personalities. With this change in place, the core md module does not need to have an exhaustive list of all possible personalities, so other personalities can be added independently. This patch also moves the check for chunksize being non-zero into the ->run routines for the personalities that need it, rather than having it in core-md. This has a side effect of allowing 'faulty' and 'linear' not to have a chunk-size set. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: break out of a loop that doesn't need to run to completionNeilBrown2006-01-061-1/+3
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: convert recently exported symbol to GPLNeilBrown2006-01-061-1/+1
| | | | | | | | ...because that seems to be the preferred practice these days. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: convert various kmap calls to kmap_atomicNeilBrown2006-01-061-23/+21
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: tidy up raid5/6 hash table codeNeilBrown2006-01-062-55/+31
| | | | | | | | | | | | | - replace open-coded hash chain with hlist macros - Fix hash-table size at one page - it is already quite generous, so there will never be a need to use multiple pages, so no need for __get_free_pages No functional change. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: convert md to use kzalloc throughoutNeilBrown2006-01-068-53/+24
| | | | | | | | Replace multiple kmalloc/memset pairs with kzalloc calls. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: clean up 'page' related names in mdNeilBrown2006-01-067-38/+38
| | | | | | | | | | | | | | | | | Substitute: page_cache_get -> get_page page_cache_release -> put_page PAGE_CACHE_SHIFT -> PAGE_SHIFT PAGE_CACHE_SIZE -> PAGE_SIZE PAGE_CACHE_MASK -> PAGE_MASK __free_page -> put_page because we aren't using the page cache, we are just using pages. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: make /proc/mdstat pollableNeilBrown2006-01-061-5/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With this patch it is possible to poll /proc/mdstat to detect arrays appearing or disappearing, to detect failures, recovery starting, recovery completing, and devices being added and removed. It is similar to the poll-ability of /proc/mounts, though different in that: We always report that the file is readable (because face it, it is, even if only for EOF). We report POLLPRI when there is a change so that select() can detect it as an exceptional event. Not only are these exceptional events, but that is the mechanism that the current 'mdadm' uses to watch for events (It also polls after a timeout). (We also report POLLERR like /proc/mounts). Finally, we only reset the per-file event counter when the start of the file is read, rather than when poll() returns an event. This is more robust as it means that an fd will continue to report activity to poll/select until the program clearly responds to that activity. md_new_event takes an 'mddev' which isn't currently used, but it will be soon. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: raid10 read-error handling - resync and read-onlyNeilBrown2006-01-061-21/+35
| | | | | | | | | | | | | | | | | | Add in correct read-error handling for resync and read-only situations. When read-only, we don't over-write, so we need to mark the failed drive in the r10_bio so we don't re-try it. During resync, we always read all blocks, so if there is a read error, we simply over-write it with the good block that we found (assuming we found one). Note that the recovery case still isn't handled in an interesting way. There is nothing useful to do for the 2-copies case. If there are 3 or more copies, then we could try reading from one of the non-missing copies, but this is a bit complicated and very rarely would be used, so I'm leaving it for now. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: auto-correct correctable read errors in raid10NeilBrown2006-01-061-15/+112
| | | | | | | | Largely just a cross-port from raid1. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: make sure read error on last working drive of raid1 actually ↵NeilBrown2006-01-061-1/+2
| | | | | | | | | | | | returns failure We are inadvertently setting the R1BIO_Uptodate bit on read errors when we decide not to try correcting (because there are no other working devices). This means that the read error is reported to the client as success. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow raid1 to check consistencyNeilBrown2006-01-061-28/+128
| | | | | | | | | | Where performing a user-requested 'check' or 'repair', we read all readable devices, and compare the contents. We only write to blocks which had read errors, or blocks with content that differs from the first good device found. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: support check-without-repair of raid10 arraysNeilBrown2006-01-061-0/+4
| | | | | | | | Also keep count on the number of errors found. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix up some rdev rcu locking in raid5/6NeilBrown2006-01-062-19/+16
| | | | | | | | | | | | | | | | | | | | | | | There is this "FIXME" comment with a typo in it!! that been annoying me for days, so I just had to remove it. conf->disks[i].rdev should only be accessed if - we know we hold a reference or - the mddev->reconfig_sem is down or - we have a rcu_readlock handle_stripe was referencing rdev in three places without any of these. For the first two, get an rcu_readlock. For the last, the same access (md_sync_acct call) is made a little later after the rdev has been claimed under and rcu_readlock, if R5_Syncio is set. So just use that access... However R5_Syncio isn't really needed as the 'syncing' variable contains the same information. So use that instead. Issues, comment, and fix are identical in raid5 and raid6. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: handle errors when read-onlyNeilBrown2006-01-061-7/+11
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: better handling for read error in raid1 during resyncNeilBrown2006-01-061-21/+78
| | | | | | | | | | | | | | | | Handling of read errors during resync is separate from handling of read errors during normal IO in raid1. A previous patch added support for read errors during normal IO. This one adds support for read errors during resync or recovery. The key differences are that we don't need to freeze the array, because the normal handling of resync means that this part of the array will be idle except for resync, and the read/overwrite/re-read is needed in a separate piece of code. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: tidyup some issues with raid1 resync and prepare for catching ↵NeilBrown2006-01-061-54/+56
| | | | | | | | | | read errors We are dereferencing ->rdev without an rcu lock! Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: attempt to auto-correct read errors in raid1NeilBrown2006-01-062-10/+106
| | | | | | | | | | | | | | On a read-error we suspend the array, then synchronously read the block from other arrays until we find one where we can read it. Then we try writing the good data back everywhere and make sure it works. If any write or subsequent read fails, only then do we fail the device out of the array. To be able to suspend the array, we need to also keep track of how many requests are queued for handling by raid1d. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: improve handing of read errors with raid6NeilBrown2006-01-061-4/+66
| | | | | | | | | | This is a simple port of match functionality across from raid5. If we get a read error, we don't kick the drive straight away, but try to over-write with good data first. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: fix raid6 resync check/repair codeNeilBrown2006-01-061-76/+106
| | | | | | | | | | | | | | | | | | raid6 currently does not check the P/Q syndromes when doing a resync, it just calculates the correct value and writes it. Doing the check can reduce writes (often to 0) for a resync, and it is needed to properly implement the echo check > sync_action operation. This patch implements the appropriate checks and tidies up some related code. It also allows raid6 user-requested resync to bypass the intent bitmap. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: write intent bitmap support for raid10NeilBrown2006-01-062-25/+163
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: move bitmap_create to after md array has been initialisedNeilBrown2006-01-065-35/+15
| | | | | | | | | | | | | | | | | This is important because bitmap_create uses mddev->resync_max_sectors and that doesn't have a valid value until after the array has been initialised (with pers->run()). [It doesn't make a difference for current personalities that support bitmaps, but will make a difference for raid10] This has the added advantage of meaning with can move the thread->timeout manipulation inside the bitmap.c code instead of sprinkling identical code throughout all personalities. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: allow dirty raid[456] arrays to be started at bootNeilBrown2006-01-063-8/+24
| | | | | | | | See patch to md.txt for more details Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: small cleanups for raid5NeilBrown2006-01-061-20/+21
| | | | | | | | | | | | | | | | | Resync code: A test that isn't needed, a 'compute_block' that makes more sense elsewhere (And then doesn't need a test), a couple of BUG_ONs to confirm the change makes sense. Printks: A few were missing KERN_* Also fix a typo in a comment.. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: improve raid10 "IO Barrier" conceptNeilBrown2006-01-061-56/+79
| | | | | | | | | | | | | raid10 needs to put up a barrier to new requests while it does resync or other background recovery. The code for this is currently open-coded, slighty obscure by its use of two waitqueues, and not documented. This patch gathers all the related code into 4 functions, and includes a comment which (hopefully) explains what is happening. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] md: improve raid1 "IO Barrier" conceptNeilBrown2006-01-061-78/+89
| | | | | | | | | | | | | raid1 needs to put up a barrier to new requests while it does resync or other background recovery. The code for this is currently open-coded, slighty obscure by its use of two waitqueues, and not documented. This patch gathers all the related code into 4 functions, and includes a comment which (hopefully) explains what is happening. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make dm-mirror not issue invalid resync requestsDarrick J. Wong2006-01-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I've been attempting to set up a (Host)RAID mirror with dm_mirror on 2.6.14.3, and I've been having a strange little problem. The configuration in question is a set of 9GB SCSI disks that have 17942584 sectors. I set up the dm_mirror table as such: 0 17942528 mirror core 2 2048 nosync 2 8:48 0 8:64 0 If I'm not mistaken, this sets up a 9GB RAID1 mriror with 1MB stripes across both SCSI disks. The sector count of the dm device is less than the size of the disks, so we shouldn't fall off the end. However, I always get the messages like this in dmesg when I set up the dm table: attempt to access beyond end of device sdd: rw=0, want=17958656, limit=17942584 Clearly, something is trying to read sectors past the end of the drive. I traced it down to the __rh_recovery_prepare function in dm-raid1.c, which gets called when we're putting the mirror set together. This function calls the dirty region log's get_resync_work function to see if there's any resync that needs to be done, and queues up any areas that are out of sync. The log's get_resync_work function is actually a pointer to the core_get_resync_work function in dm-log.c. The core_get_resync_work function queries a bitset lc->sync_bits to find out if there are any regions that are out of date (i.e. the bit is 0), which is where the problem occurs. If every bit in lc->sync_bits is 1 (which is the case when we've just configured a new RAID1 with the nosync option), the find_next_zero_bit does NOT return the size parameter (lc->region_count in this case), it returns the size parameter rounded up to the nearest multiple of 32! I don't know if this is intentional, but i386 and x86_64 both exhibit this behavior. In any case, the statement "if (*region == lc->region_count)" looks like it's supposed to catch the case where are no regions to resync and return 0. Since find_next_zero_bit apparently has a habit of returning a value that's larger than lc->region_count, the enclosed patch changes the equality test to a greater-than test so that we don't try to resync areas outside of the RAID1 region. Seeing as the HostRAID metadata lives just past the end of the RAID1 data, mucking around in that area is not a good idea. I suppose another way to fix this would be to amend find_next_zero_bit so that it doesn't return values larger than "size", but I don't know if there's a reason for the current behavior. Signed-Off-By: Darrick J. Wong <djwong@us.ibm.com> Acked-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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