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path: root/drivers/md/bitmap.c
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2009-06-11Merge branch 'for-2.6.31' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits) block: add request clone interface (v2) floppy: fix hibernation ramdisk: remove long-deprecated "ramdisk=" boot-time parameter fs/bio.c: add missing __user annotation block: prevent possible io_context->refcount overflow Add serial number support for virtio_blk, V4a block: Add missing bounce_pfn stacking and fix comments Revert "block: Fix bounce limit setting in DM" cciss: decode unit attention in SCSI error handling code cciss: Remove no longer needed sendcmd reject processing code cciss: change SCSI error handling routines to work with interrupts enabled. cciss: separate error processing and command retrying code in sendcmd_withirq_core() cciss: factor out fix target status processing code from sendcmd functions cciss: simplify interface of sendcmd() and sendcmd_withirq() cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code cciss: Use schedule_timeout_uninterruptible in SCSI error handling code block: needs to set the residual length of a bidi request Revert "block: implement blkdev_readpages" block: Fix bounce limit setting in DM Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt ... Manually fix conflicts with tracing updates in: block/blk-sysfs.c drivers/ide/ide-atapi.c drivers/ide/ide-cd.c drivers/ide/ide-floppy.c drivers/ide/ide-tape.c include/trace/events/block.h kernel/trace/blktrace.c
2009-05-26md: bitmap: improve bitmap maintenance code.NeilBrown
The code for checking which bits in the bitmap can be cleared has 2 problems: 1/ it repeatedly takes and drops a spinlock, where it would make more sense to just hold on to it most of the time. 2/ it doesn't make use of some opportunities to skip large sections of the bitmap This patch fixes those. It will only affect CPU consumption, not correctness. Signed-off-by: NeilBrown <neilb@suse.de>
2009-05-22block: Do away with the notion of hardsect_sizeMartin K. Petersen
Until now we have had a 1:1 mapping between storage device physical block size and the logical block sized used when addressing the device. With SATA 4KB drives coming out that will no longer be the case. The sector size will be 4KB but the logical block size will remain 512-bytes. Hence we need to distinguish between the physical block size and the logical ditto. This patch renames hardsect_size to logical_block_size. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-07md: fix some (more) errors with bitmaps on devices larger than 2TB.NeilBrown
If a write intent bitmap covers more than 2TB, we sometimes work with values beyond 32bit, so these need to be sector_t. This patches add the required casts to some unsigned longs that are being shifted up. This will affect any raid10 larger than 2TB, or any raid1/4/5/6 with member devices that are larger than 2TB. Signed-off-by: NeilBrown <neilb@suse.de> Reported-by: "Mario 'BitKoenig' Holbe" <Mario.Holbe@TU-Ilmenau.DE> Cc: stable@kernel.org
2009-05-07md: fix loading of out-of-date bitmap.NeilBrown
When md is loading a bitmap which it knows is out of date, it fills each page with 1s and writes it back out again. However the write_page call makes used of bitmap->file_pages and bitmap->last_page_size which haven't been set correctly yet. So this can sometimes fail. Move the setting of file_pages and last_page_size to before the call to write_page. This bug can cause the assembly on an array to fail, thus making the data inaccessible. Hence I think it is a suitable candidate for -stable. Cc: stable@kernel.org Reported-by: Vojtech Pavlik <vojtech@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de>
2009-04-20md: support bitmaps on RAID10 arrays larger then 2 terabytesNeilBrown
.. and other arrays with components larger than 2 terabytes. We use a "long" rather than a "sector_t" in part of the bitmap size calculations, which is sad. Reported-by: "Mario 'BitKoenig' Holbe" <Mario.Holbe@TU-Ilmenau.DE> Signed-off-by: NeilBrown <neilb@suse.de>
2009-04-14md: improve usefulness and accuracy of sysfs file md/sync_completed.NeilBrown
The sync_completed file reports how much of a resync (or recovery or reshape) has been completed. However due to the possibility of out-of-order completion of writes, it is not certain to be accurate. We have an internal value - mddev->curr_resync_completed - which is an accurate value (though it might not always be quite so uptodate). So: - make curr_resync_completed be uptodate a little more often, particularly when raid5 reshape updates status in the metadata - report curr_resync_completed in the sysfs file - allow poll/select to report all updates to md/sync_completed. This makes sync_completed completed usable by any external metadata handler that wants to record this status information in its metadata. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: Make mddev->size sector-based.Andre Noll
This patch renames the "size" field of struct mddev_s to "dev_sectors" and stores the number of 512-byte sectors instead of the number of 1K-blocks in it. All users of that field, including raid levels 1,4-6,10, are adjusted accordingly. This simplifies the code a bit because it allows to get rid of a couple of divisions/multiplications by two. In order to make checkpatch happy, some minor coding style issues have also been addressed. In particular, size_store() now uses strict_strtoull() instead of simple_strtoull(). Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: occasionally checkpoint drive recovery to reduce duplicate effort after ↵NeilBrown
a crash Version 1.x metadata has the ability to record the status of a partially completed drive recovery. However we only update that record on a clean shutdown. It would be nice to update it on unclean shutdowns too, particularly when using a bitmap that removes much to the 'sync' effort after an unclean shutdown. One complication with checkpointing recovery is that we only know where we are up to in terms of IO requests started, not which ones have completed. And we need to know what has completed to record how much is recovered. So occasionally pause the recovery until all submitted requests are completed, then update the record of where we are up to. When we have a bitmap, we already do that pause occasionally to keep the bitmap up-to-date. So enhance that code to record the recovery offset and schedule a superblock update. And when there is no bitmap, just pause 16 times during the resync to do a checkpoint. '16' is a fairly arbitrary number. But we don't really have any good way to judge how often is acceptable, and it seems like a reasonable number for now. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: move md_k.h from include/linux/raid/ to drivers/md/NeilBrown
It really is nicer to keep related code together.. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: move lots of #include lines out of .h files and into .cNeilBrown
This makes the includes more explicit, and is preparation for moving md_k.h to drivers/md/md.h Remove include/raid/md.h as its only remaining use was to #include other files. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: move headers out of include/linux/raid/Christoph Hellwig
Move the headers with the local structures for the disciplines and bitmap.h into drivers/md/ so that they are more easily grepable for hacking and not far away. md.h is left where it is for now as there are some uses from the outside. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: write bitmap information to devices that are undergoing recovery.NeilBrown
When we add some spares to an array and start recovery, and we have a bitmap which is stored 'internally' on all devices, we call bitmap_write_all to make sure the bitmap is correct on the new device(s). However that doesn't work as write_sb_page only writes to 'In_sync' devices, and devices undergoing recovery are not 'In_sync' until recovery finishes. So extend write_sb_page (actually next_active_rdev) to include devices that are under recovery. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: never clear bit from the write-intent bitmap when the array is degraded.NeilBrown
It is safe to clear a bit from the write-intent bitmap for a raid1 if we know the data has been written to all devices, which is what the current test does. But it is not always safe to update the 'events_cleared' counter in that case. This is because one request could complete successfully after some other request has partially failed. So simply disable the clearing and updating of events_cleared whenever the array is degraded. This might end up not clearing some bits that could safely be cleared, but it is safest approach. Note that the bug fixed here did not risk corrupting data by letting the array get out-of-sync. Rather it meant that when a device is removed and re-added to the array, it might incorrectly require a full recovery rather than just recovering based on the bitmap. Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31md: Allow write-intent bitmaps to have chunksize < PAGE_SIZENeilBrown
md currently insists that the chunk size used for write-intent bitmaps (the amount of data that corresponds to one chunk) be at least one page. The reason for this restriction is lost in the mists of time, but a review of the code (and a vague memory) suggests that the only problem would be related to resync. Resync tries very hard to work in multiples of a page, but also needs to sync with units of a bitmap_chunk too. This connection comes out in the bitmap_start_sync call. So change bitmap_start_sync to always work in multiples of a page. If the bitmap chunk size is less that one page, we flag multiple chunks as 'syncing' and generally make them all appear to the resync routines like one chunk. All other code either already works with data ranges that could span multiple chunks, or explicitly only cares about a single chunk. Signed-off-by: Neil Brown <neilb@suse.de>
2009-01-09md: use list_for_each_entry macro directlyCheng Renquan
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>
2009-01-09md: fix bitmap-on-external-file bug.NeilBrown
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
2008-12-19md: Don't read past end of bitmap when reading bitmap.NeilBrown
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
2008-09-01Fix problem with waiting while holding rcu read lock in md/bitmap.cNeilBrown
A recent patch to protect the rdev list with rcu locking leaves us with a problem because we can sleep on memalloc while holding the rcu lock. The rcu lock is only needed while walking the linked list as uninteresting devices (failed or spares) can be removed at any time. So only take the rcu lock while actually walking the linked list. Take a refcount on the rdev during the time when we drop the lock and do the memalloc to start IO. When we return to the locked code, all the interesting devices on the list will not have moved, so we can simply use list_for_each_continue_rcu to pick up where we left off. Signed-off-by: NeilBrown <neilb@suse.de>
2008-08-01md: the bitmap code needs to use blk_plug_device_unlocked()Jens Axboe
It doesn't hold the queue lock, so it's both racey on the queue flags and thus spews a warning. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-21md: Protect access to mddev->disks list using RCUNeilBrown
All modifications and most access to the mddev->disks list are made under the reconfig_mutex lock. However there are three places where the list is walked without any locking. If a reconfig happens at this time, havoc (and oops) can ensue. So use RCU to protect these accesses: - wrap them in rcu_read_{,un}lock() - use list_for_each_entry_rcu - add to the list with list_add_rcu - delete from the list with list_del_rcu - delay the 'free' with call_rcu rather than schedule_work Note that export_rdev did a list_del_init on this list. In almost all cases the entry was not in the list anymore so it was a no-op and so safe. It is no longer safe as after list_del_rcu we may not touch the list_head. An audit shows that export_rdev is called: - after unbind_rdev_from_array, in which case the delete has already been done, - after bind_rdev_to_array fails, in which case the delete isn't needed. - before the device has been put on a list at all (e.g. in add_new_disk where reading the superblock fails). - and in autorun devices after a failure when the device is on a different list. So remove the list_del_init call from export_rdev, and add it back immediately before the called to export_rdev for that last case. Note also that ->same_set is sometimes used for lists other than mddev->list (e.g. candidates). In these cases rcu is not needed. Signed-off-by: NeilBrown <neilb@suse.de>
2008-07-11md: Turn rdev->sb_offset into a sector-based quantity.Andre Noll
Rename it to sb_start to make sure all users have been converted. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: Neil Brown <neilb@suse.de>
2008-06-28Improve setting of "events_cleared" for write-intent bitmaps.Neil Brown
When an array is degraded, bits in the write-intent bitmap are not cleared, so that if the missing device is re-added, it can be synced by only updated those parts of the device that have changed since it was removed. The enable this a 'events_cleared' value is stored. It is the event counter for the array the last time that any bits were cleared. Sometimes - if a device disappears from an array while it is 'clean' - the events_cleared value gets updated incorrectly (there are subtle ordering issues between updateing events in the main metadata and the bitmap metadata) resulting in the missing device appearing to require a full resync when it is re-added. With this patch, we update events_cleared precisely when we are about to clear a bit in the bitmap. We record events_cleared when we clear the bit internally, and copy that to the superblock which is written out before the bit on storage. This makes it more "obviously correct". We also need to update events_cleared when the event_count is going backwards (as happens on a dirty->clean transition of a non-degraded array). Thanks to Mike Snitzer for identifying this problem and testing early "fixes". Cc: "Mike Snitzer" <snitzer@gmail.com> Signed-off-by: Neil Brown <neilb@suse.de>
2008-05-24md: kill file_path wrapperChristoph Hellwig
Kill the trivial and rather pointless file_path wrapper around d_path. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10md: reduce CPU wastage on idle md array with a write-intent bitmapNeilBrown
Recent patch titled Reduce CPU wastage on idle md array with a write-intent bitmap. would sometimes leave the array with dirty bitmap bits that stay dirty. A subsequent write would sort things out so it isn't a big problem, but should be fixed nonetheless. We need to make sure that when the bitmap becomes not "allclean", the daemon_sleep really does get set to a sensible value. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-04md: reduce CPU wastage on idle md array with a write-intent bitmapNeilBrown
On an md array with a write-intent bitmap, a thread wakes up every few seconds and scans the bitmap looking for work to do. If the array is idle, there will be no work to do, but a lot of scanning is done to discover this. So cache the fact that the bitmap is completely clean, and avoid scanning the whole bitmap when the cache is known to be clean. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14d_path: Make d_path() use a struct pathJan Blunck
d_path() is used on a <dentry,vfsmount> pair. Lets use a struct path to reflect this. [akpm@linux-foundation.org: fix build in mm/memory.c] Signed-off-by: Jan Blunck <jblunck@suse.de> Acked-by: Bryan Wu <bryan.wu@analog.com> Acked-by: Christoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Neil Brown <neilb@suse.de> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06md: change ITERATE_RDEV to rdev_for_eachNeilBrown
As this is more in line with common practice in the kernel. Also swap the args around to be more like list_for_each. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06md: Update md bitmap during resync.NeilBrown
Currently an md array with a write-intent bitmap does not updated that bitmap to reflect successful partial resync. Rather the entire bitmap is updated when the resync completes. This is because there is no guarentee that resync requests will complete in order, and tracking each request individually is unnecessarily burdensome. However there is value in regularly updating the bitmap, so add code to periodically pause while all pending sync requests complete, then update the bitmap. Doing this only every few seconds (the same as the bitmap update time) does not notciably affect resync performance. [snitzer@gmail.com: export bitmap_cond_end_sync] Signed-off-by: Neil Brown <neilb@suse.de> Cc: "Mike Snitzer" <snitzer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-09Add UNPLUG traces to all appropriate placesAlan D. Brunelle
Added blk_unplug interface, allowing all invocations of unplugs to result in a generated blktrace UNPLUG. Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-23md: fix an unsigned compare to allow creation of bitmaps with v1.0 metadataNeilBrown
As page->index is unsigned, this all becomes an unsigned comparison, which almost always returns an error. Signed-off-by: Neil Brown <neilb@suse.de> Cc: Stable <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17md: change bitmap_unplug and others to void functionsNeilBrown
bitmap_unplug only ever returns 0, so it may as well be void. Two callers try to print a message if it returns non-zero, but that message is already printed by bitmap_file_kick. write_page returns an error which is not consistently checked. It always causes BITMAP_WRITE_ERROR to be set on an error, and that can more conveniently be checked. When the return of write_page is checked, an error causes bitmap_file_kick to be called - so move that call into write_page - and protect against recursive calls into bitmap_file_kick. bitmap_update_sb returns an error that is never checked. So make these 'void' and be consistent about checking the bit. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17md: check that internal bitmap does not overlap other dataNeilBrown
We current completely trust user-space to set up metadata describing an consistant array. In particlar, that the metadata, data, and bitmap do not overlap. But userspace can be buggy, and it is better to report an error than corrupt data. So put in some appropriate checks. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23md: don't write more than is required of the last page of a bitmapNeilBrown
It is possible that real data or metadata follows the bitmap without full page alignment. So limit the last write to be only the required number of bytes, rounded up to the hard sector size of the device. Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08Remove do_sync_file_range()Mark Fasheh
Remove do_sync_file_range() and convert callers to just use do_sync_mapping_range(). Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-12[PATCH] md: fix calculation for size of filemap_attr array in md/bitmapNeil Brown
If 'num_pages' were ever 1 more than a multiple of 8 (32bit platforms) or of 16 (64 bit platforms). filemap_attr would be allocated one 'unsigned long' shorter than required. We need a round-up in there. Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] remove invalidate_inode_pages()Andrew Morton
Convert all calls to invalidate_inode_pages() into open-coded calls to invalidate_mapping_pages(). Leave the invalidate_inode_pages() wrapper in place for now, marked as deprecated. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-09[PATCH] md: avoid possible BUG_ON in md bitmap handlingNeil Brown
md/bitmap tracks how many active write requests are pending on blocks associated with each bit in the bitmap, so that it knows when it can clear the bit (when count hits zero). The counter has 14 bits of space, so if there are ever more than 16383, we cannot cope. Currently the code just calles BUG_ON as "all" drivers have request queue limits much smaller than this. However is seems that some don't. Apparently some multipath configurations can allow more than 16383 concurrent write requests. So, in this unlikely situation, instead of calling BUG_ON we now wait for the count to drop down a bit. This requires a new wait_queue_head, some waiting code, and a wakeup call. Tested by limiting the counter to 20 instead of 16383 (writes go a lot slower in that case...). Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-26[PATCH] md: avoid reading past the end of a bitmap fileNeilBrown
In most cases we check the size of the bitmap file before reading data from it. However when reading the superblock, we always read the first PAGE_SIZE bytes, which might not always be appropriate. So limit that read to the size of the file if appropriate. Also, we get the count of available bytes wrong in one place, so that too can read past the end of the file. Cc: "yang yin" <yinyang801120@gmail.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-08[PATCH] struct path: convert mdJosef Sipek
Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-21[PATCH] md: endian annotations for the bitmap superblockNeilBrown
And a couple of bug fixes found by sparse. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] md: use BUILD_BUG_ONAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03[PATCH] md: use ffz instead of find_first_set to convert multiplier to shiftPaul Clements
find_first_set doesn't find the least-significant bit on bigendian machines, so it is really wrong to use it. ffs is closer, but takes an 'int' and we have a 'unsigned long'. So use ffz(~X) to convert a chunksize into a chunkshift. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03[PATCH] md: new sysfs interface for setting bits in the write-intent-bitmapPaul Clements
Add a new sysfs interface that allows the bitmap of an array to be dirtied. The interface is write-only, and is used as follows: echo "1000" > /sys/block/md2/md/bitmap (dirty the bit for chunk 1000 [offset 0] in the in-memory and on-disk bitmaps of array md2) echo "1000-2000" > /sys/block/md1/md/bitmap (dirty the bits for chunks 1000-2000 in md1's bitmap) This is useful, for example, in cluster environments where you may need to combine two disjoint bitmaps into one (following a server failure, after a secondary server has taken over the array). By combining the bitmaps on the two servers, a full resync can be avoided (This was discussed on the list back on March 18, 2005, "[PATCH 1/2] md bitmap bug fixes" thread). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-26[PATCH] md: Change md/bitmap file handling to use bmap to file blocks-fixNeilBrown
Fix problems with new bmap based access to bitmap files. 1/ When not using a file based bitmap, attach a NULL list of buffers to each page so the common free_buffer routine can cope. 2/ Use submit_bh to read as well as write, rather than vfs_read. This makes read and write more symetric. 3/ sync the file before reading, to ensure that the page cache has no dirty pages that might get written out later. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocksNeilBrown
If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] md/bitmap: tidy up i_writecount handling in md/bitmapNeilBrown
md/bitmap modifies i_writecount of a bitmap file to make sure that no-one else writes to it. The reverting of the change is sometimes done twice, and there is one error path where it is omitted. This patch tidies that up. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] md/bitmap: remove dead code from md/bitmapNeilBrown
bitmap_active is never called, and the BITMAP_ACTIVE flag is never users or tested, so discard them both. Also remove some out-of-date 'todo' comments. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] md/bitmap: remove unnecessary page reference manipulations from ↵NeilBrown
md/bitmap code md/bitmap gets a collection of pages representing the bitmap when it initialises the bitmap, and puts all the references when discarding the bitmap. It also occasionally takes extra references without any good reason, and sometimes drops them ... though it doesn't always drop them, which can result in a memory leak. This patch removes the unnecessary 'get_page' calls, and the corresponding 'put_page' 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>