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path: root/include/linux/raid/raid5.h
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2006-12-10[PATCH] md: allow reads that have bypassed the cache to be retried on failureRaz Ben-Jehuda(caro)
If a bypass-the-cache read fails, we simply try again through the cache. If it fails again it will trigger normal recovery precedures. update 1: From: NeilBrown <neilb@suse.de> 1/ chunk_aligned_read and retry_aligned_read assume that data_disks == raid_disks - 1 which is not true for raid6. So when an aligned read request bypasses the cache, we can get the wrong data. 2/ The cloned bio is being used-after-free in raid5_align_endio (to test BIO_UPTODATE). 3/ We forgot to add rdev->data_offset when submitting a bio for aligned-read 4/ clone_bio calls blk_recount_segments and then we change bi_bdev, so we need to invalidate the segment counts. 5/ We don't de-reference the rdev when the read completes. This means we need to record the rdev to so it is still available in the end_io routine. Fortunately bi_next in the original bio is unused at this point so we can stuff it in there. 6/ We leak a cloned bio if the target rdev is not usable. From: NeilBrown <neilb@suse.de> update 2: 1/ When aligned requests fail (read error) they need to be retried via the normal method (stripe cache). As we cannot be sure that we can process a single read in one go (we may not be able to allocate all the stripes needed) we store a bio-being-retried and a list of bioes-that-still-need-to-be-retried. When find a bio that needs to be retried, we should add it to the list, not to single-bio... 2/ We were never incrementing 'scnt' when resubmitting failed aligned requests. [akpm@osdl.org: build fix] Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove kmem_cache_tChristoph Lameter
Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03[PATCH] md: remove the working_disks and failed_disks from raid5 state data.NeilBrown
They are not needed. conf->failed_disks is the same as mddev->degraded and conf->working_disks is conf->raid_disks - mddev->degraded. 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: fix a comment that is wrong in raid5.hNeilBrown
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: merge raid5 and raid6 codeNeilBrown
There is a lot of commonality between raid5.c and raid6main.c. This patches merges both into one module called raid456. This saves a lot of code, and paves the way for online raid5->raid6 migrations. There is still duplication, e.g. between handle_stripe5 and handle_stripe6. This will probably be cleaned up later. Cc: "H. Peter Anvin" <hpa@zytor.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>
2006-03-27[PATCH] md: Only checkpoint expansion progress occasionallyNeilBrown
Instead of checkpointing at each stripe, only checkpoint when a new write would overwrite uncheckpointed data. Block any write to the uncheckpointed area. Arbitrarily checkpoint at least every 3Meg. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] md: Checkpoint and allow restart of raid5 reshapeNeilBrown
We allow the superblock to record an 'old' and a 'new' geometry, and a position where any conversion is up to. The geometry allows for changing chunksize, layout and level as well as number of devices. When using verion-0.90 superblock, we convert the version to 0.91 while the conversion is happening so that an old kernel will refuse the assemble the array. For version-1, we use a feature bit for the same effect. When starting an array we check for an incomplete reshape and restart the reshape process if needed. If the reshape stopped at an awkward time (like when updating the first stripe) we refuse to assemble the array, and let user-space worry about it. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] md: Core of raid5 resize processNeilBrown
This patch provides the core of the resize/expand process. sync_request notices if a 'reshape' is happening and acts accordingly. It allocated new stripe_heads for the next chunk-wide-stripe in the target geometry, marking them STRIPE_EXPANDING. Then it finds which stripe heads in the old geometry can provide data needed by these and marks them STRIPE_EXPAND_SOURCE. This causes stripe_handle to read all blocks on those stripes. Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, any that are needed are copied into the corresponding STRIPE_EXPANDING stripe_head. Once a STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY and then is written out and released. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] md: Infrastructure to allow normal IO to continue while array is ↵NeilBrown
expanding We need to allow that different stripes are of different effective sizes, and use the appropriate size. Also, when a stripe is being expanded, we must block any IO attempts until the stripe is stable again. Key elements in this change are: - each stripe_head gets a 'disk' field which is part of the key, thus there can sometimes be two stripe heads of the same area of the array, but covering different numbers of devices. One of these will be marked STRIPE_EXPANDING and so won't accept new requests. - conf->expand_progress tracks how the expansion is progressing and is used to determine whether the target part of the array has been expanded yet or not. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] md: Allow stripes to be expanded in preparation for expanding an arrayNeilBrown
Before a RAID-5 can be expanded, we need to be able to expand the stripe-cache data structure. This requires allocating new stripes in a new kmem_cache. If this succeeds, we copy cache pages over and release the old stripes and kmem_cache. We then allocate new pages. If that fails, we leave the stripe cache at it's new size. It isn't worth the effort to shrink it back again. Unfortuanately this means we need two kmem_cache names as we, for a short period of time, we have two kmem_caches. So they are raid5/%s and raid5/%s-alt Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27[PATCH] md: Split disks array out of raid5 conf structure so it is easier to ↵NeilBrown
grow The remainder of this batch implements raid5 reshaping. Currently the only shape change that is supported is added a device, but it is envisioned that changing the chunksize and layout will also be supported, as well as changing the level (e.g. 1->5, 5->6). The reshape process naturally has to move all of the data in the array, and so should be used with caution. It is believed to work, and some testing does support this, but wider testing would be great for increasing my confidence. You will need a version of mdadm newer than 2.3.1 to make use of raid5 growth. This is because mdadm need to take a copy of a 'critical section' at the start of the array incase there is a crash at an awkward moment. On restart, mdadm will restore the critical section and allow reshape to continue. I hope to release a 2.4-pre by early next week - it still needs a little more polishing. This patch: Previously the array of disk information was included in the raid5 'conf' structure which was allocated to an appropriate size. This makes it awkward to change the size of that array. So we split it off into a separate kmalloced array which will require a little extra indexing, but is much easier to grow. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] md: tidy up raid5/6 hash table codeNeilBrown
- 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>
2006-01-06[PATCH] md: fix up some rdev rcu locking in raid5/6NeilBrown
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>
2006-01-06[PATCH] md: fix raid6 resync check/repair codeNeilBrown
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>
2005-11-09[PATCH] md: change raid5 sysfs attribute to not create a new directoryNeilBrown
There isn't really a need for raid5 attributes to be an a subdirectory, so this patch moves them from /sys/block/mdX/md/raid5/attribute to /sys/block/mdX/md/attribute This suggests that all md personalities should co-operate about namespace usage, but that shouldn't be a problem. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09[PATCH] md: add kobject/sysfs support to raid5NeilBrown
/sys/block/mdX/md/raid5/ contains raid5-related attributes. Currently stripe_cache_size is number of entries in stripe cache, and is settable. stripe_cache_active is number of active entries, and in only readable. Signed-off-by: Neil Brown <neilb@suse.de> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09[PATCH] md: better handling of readerrors with raid5.NeilBrown
This patch changes the behaviour of raid5 when it gets a read error. Instead of just failing the device, it tried to find out what should have been there, and writes it over the bad block. For some media-errors, this has a reasonable chance of fixing the error. If the write succeeds, and a subsequent read succeeds as well, raid5 decided the address is OK and conitnues. Instead of failing a drive on read-error, we attempt to re-write the block, and then re-read. If that all works, we allow the device to remain in the array. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] md: add write-intent-bitmap support to raid5NeilBrown
Most awkward part of this is delaying write requests until bitmap updates have been flushed. To achieve this, we have a sequence number (seq_flush) which is incremented each time the raid5 is unplugged. If the raid thread notices that this has changed, it flushes bitmap changes, and assigned the value of seq_flush to seq_write. When a write request arrives, it is given the number from seq_write, and that write request may not complete until seq_flush is larger than the saved seq number. We have a new queue for storing stripes which are waiting for a bitmap flush and an extra flag for stripes to record if the write was 'degraded' and so should not clear the a bit in the bitmap. Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!