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2009-08-19NFS: Add a dns resolver for use with NFSv4 referrals and migrationTrond Myklebust9-1/+639
The NFSv4 and NFSv4.1 protocols both allow for the redirection of a client from one server to another in order to support filesystem migration and replication. For full protocol support, we need to add the ability to convert a DNS host name into an IP address that we can feed to the RPC client. We'll reuse the sunrpc cache, now that it has been converted to work with rpc_pipefs. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-19SUNRPC: Fix a typo in cache_pipefs_filesTrond Myklebust1-1/+1
We want the channel to be a regular file, so that we don't need to supply rpc_pipe_ops. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-19Merge branch 'nfsv4_xdr_cleanups-for-2.6.32' into nfs-for-2.6.32Trond Myklebust158-1436/+3577
Conflicts: fs/nfs/nfs4xdr.c
2009-08-14nfs: nfs4xdr: optimize low level decodingBenny Halevy1-59/+59
do not increment decoding ptr if not needed. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of READ_BUFBenny Halevy1-96/+379
Use xdr_inline_decode instead. Open code debug printout and error return. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: simplify decode_exchange_id by reusing decode_opaque_inlineBenny Halevy1-9/+10
Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of COPYMEMBenny Halevy1-8/+3
Just directly call memcpy. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: introduce decode_sessionid helperBenny Halevy1-10/+15
Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: introduce decode_verifier helperBenny Halevy1-10/+12
Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Trond: Fixed up an 'uninitialised variable' issue in decode_readdir] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: introduce decode_opaque_fixed and decode_stateid helpersBenny Halevy1-31/+40
Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: introduce print_overflow_msgBenny Halevy1-4/+8
Part fo the nfs4xdr cleanup. READ_BUF will go away. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of READTIMEBenny Halevy1-5/+0
It has no users. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of READ64Benny Halevy1-29/+25
s/READ64\(\*(.*)\)/p = xdr_decode_hyper(p, \1)/ s/READ64\((.*)\)/p = xdr_decode_hyper(p, &\1)/ Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of READ32Benny Halevy1-73/+72
s/READ32\((.*)\)/\1 = be32_to_cpup(p++)/ Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: merge xdr_encode_int+xdr_encode_opaque_fixed into ↵Benny Halevy1-28/+14
xdr_encode_opaque use encode_string where appropriate. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: optimize low level encodingBenny Halevy1-64/+64
do not increment encoding ptr if not needed. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: change RESERVE_SPACE macro into a static helperBenny Halevy1-73/+65
In order to open code and expose the result pointer assignment. Alternatively, we can open code the call to xdr_reserve_space and do the BUG_ON an the error case at the call site. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: encode_compound_hdr does not have to round up reserved bytesBenny Halevy1-1/+1
This is already done by xdr_reserve_space and since encode_compound_hdr is adding a byte count to "12" which is already word aligned, the xdr level rounding will work just as well. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: optimize RESERVE_SPACE in encode_create_session and ↵Benny Halevy1-17/+5
encode_sequence Coalesce multilpe constant RESERVE_SPACEs into one Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of WRITEMEMBenny Halevy1-36/+32
s/WRITEMEM(/p = xdr_encode_opaque_fixed(p, / Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of WRITE64Benny Halevy1-24/+20
s/WRITE64/p = xdr_encode_hyper(p, / Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14nfs: nfs4xdr: get rid of WRITE32Benny Halevy1-146/+145
s/WRITE32/*p++ = cpu_to_be32/ Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14sunrpc: ntoh -> be*_to_cpuBenny Halevy2-6/+5
ntohl is already defined as be32_to_cpu. be64_to_cpu has architecture specific optimized implementations. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-14sunrpc: hton -> cpu_to_be*Benny Halevy2-6/+5
htonl is already defined as cpu_to_be32. cpu_to_be64 has architecture specific optimized implementations. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-13Linux 2.6.31-rc6v2.6.31-rc6Linus Torvalds1-1/+1
2009-08-13genirq: prevent wakeup of freed irq threadLinus Torvalds1-10/+7
free_irq() can remove an irqaction while the corresponding interrupt is in progress, but free_irq() sets action->thread to NULL unconditionally, which might lead to a NULL pointer dereference in handle_IRQ_event() when the hard interrupt context tries to wake up the handler thread. Prevent this by moving the thread stop after synchronize_irq(). No need to set action->thread to NULL either as action is going to be freed anyway. This fixes a boot crash reported against preempt-rt which uses the mainline irq threads code to implement full irq threading. [ tglx: removed local irqthread variable ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-13Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds11-190/+429
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Report the cloning task as parent on perf_counter_fork() perf_counter: Fix an ipi-deadlock perf: Rework/fix the whole read vs group stuff perf_counter: Fix swcounter context invariance perf report: Don't show unresolved DSOs and symbols when -S/-d is used perf tools: Add a general option to enable raw sample records perf tools: Add a per tracepoint counter attribute to get raw sample perf_counter: Provide hw_perf_counter_setup_online() APIs perf list: Fix large list output by using the pager perf_counter, x86: Fix/improve apic fallback perf record: Add missing -C option support for specifying profile cpu perf tools: Fix dso__new handle() to handle deleted DSOs perf tools: Fix fallback to cplus_demangle() when bfd_demangle() is not available perf report: Show the tid too in -D perf record: Fix .tid and .pid fill-in when synthesizing events perf_counter, x86: Fix generic cache events on P6-mobile CPUs perf_counter, x86: Fix lapic printk message
2009-08-13Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds4-11/+37
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix handling of bad requeue syscall pairing futex: Fix compat_futex to be same as futex for REQUEUE_PI locking, sched: Give waitqueue spinlocks their own lockdep classes futex: Update futex_q lock_ptr on requeue proxy lock
2009-08-13Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds4-37/+48
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix oops in identify_cpu() on CPUs without CPUID x86: Clear incorrectly forced X86_FEATURE_LAHF_LM flag x86, mce: therm_throt - change when we print messages x86: Add reboot quirk for every 5 series MacBook/Pro
2009-08-13Merge branch 'upstream-linus' of ↵Linus Torvalds16-135/+357
git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2 * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2: (22 commits) ocfs2: Fix possible deadlock when extending quota file ocfs2: keep index within status_map[] ocfs2: Initialize the cluster we're writing to in a non-sparse extend ocfs2: Remove redundant BUG_ON in __dlm_queue_ast() ocfs2/quota: Release lock for error in ocfs2_quota_write. ocfs2: Define credit counts for quota operations ocfs2: Remove syncjiff field from quota info ocfs2: Fix initialization of blockcheck stats ocfs2: Zero out padding of on disk dquot structure ocfs2: Initialize blocks allocated to local quota file ocfs2: Mark buffer uptodate before calling ocfs2_journal_access_dq() ocfs2: Make global quota files blocksize aligned ocfs2: Use ocfs2_rec_clusters in ocfs2_adjust_adjacent_records. ocfs2: Fix deadlock on umount ocfs2: Add extra credits and access the modified bh in update_edge_lengths. ocfs2: Fail ocfs2_get_block() immediately when a block needs allocation ocfs2: Fix error return in ocfs2_write_cluster() ocfs2: Fix compilation warning for fs/ocfs2/xattr.c ocfs2: Initialize count in aio_write before generic_write_checks ocfs2: log the actual return value of ocfs2_file_aio_write() ...
2009-08-13Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds3-20/+56
* 'for-linus' of git://neil.brown.name/md: md: allow upper limit for resync/reshape to be set when array is read-only md/raid5: Properly remove excess drives after shrinking a raid5/6 md/raid5: make sure a reshape restarts at the correct address. md/raid5: allow new reshape modes to be restarted in the middle. md: never advance 'events' counter by more than 1. Remove deadlock potential in md_open
2009-08-13Merge branch 'sh/for-2.6.31' of ↵Linus Torvalds26-26/+26
git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 * 'sh/for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: fix i2c init order on ap325rxa V2 sh: fix i2c init order on Migo-R V2 sh: convert processor device setup functions to arch_initcall()
2009-08-13Make sock_sendpage() use kernel_sendpage()Linus Torvalds1-1/+1
kernel_sendpage() does the proper default case handling for when the socket doesn't have a native sendpage implementation. Now, arguably this might be something that we could instead solve by just specifying that all protocols should do it themselves at the protocol level, but we really only care about the common protocols. Does anybody really care about sendpage on something like Appletalk? Not likely. Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Julien TINNES <julien@cr0.org> Acked-by: Tavis Ormandy <taviso@sdf.lonestar.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-13perf_counter: Report the cloning task as parent on perf_counter_fork()Peter Zijlstra1-2/+2
A bug in (9f498cc: perf_counter: Full task tracing) makes profiling multi-threaded apps it go belly up. [ output as: (PID:TID):(PPID:PTID) ] # ./perf report -D | grep FORK 0x4b0 [0x18]: PERF_EVENT_FORK: (3237:3237):(3236:3236) 0xa10 [0x18]: PERF_EVENT_FORK: (3237:3238):(3236:3236) 0xa70 [0x18]: PERF_EVENT_FORK: (3237:3239):(3236:3236) 0xad0 [0x18]: PERF_EVENT_FORK: (3237:3240):(3236:3236) 0xb18 [0x18]: PERF_EVENT_FORK: (3237:3241):(3236:3236) Shows us that the test (27d028d perf report: Update for the new FORK/EXIT events) in builtin-report.c: /* * A thread clone will have the same PID for both * parent and child. */ if (thread == parent) return 0; Will clearly fail. The problem is that perf_counter_fork() reports the actual parent, instead of the cloning thread. Fixing that (with the below patch), yields: # ./perf report -D | grep FORK 0x4c8 [0x18]: PERF_EVENT_FORK: (1590:1590):(1589:1589) 0xbd8 [0x18]: PERF_EVENT_FORK: (1590:1591):(1590:1590) 0xc80 [0x18]: PERF_EVENT_FORK: (1590:1592):(1590:1590) 0x3338 [0x18]: PERF_EVENT_FORK: (1590:1593):(1590:1590) 0x66b0 [0x18]: PERF_EVENT_FORK: (1590:1594):(1590:1590) Which both makes more sense and doesn't confuse perf report anymore. Reported-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: paulus@samba.org Cc: Anton Blanchard <anton@samba.org> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <1250172882.5241.62.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Fix an ipi-deadlockPeter Zijlstra1-1/+5
perf_pending_counter() is called from IRQ context and will call perf_counter_disable(), however perf_counter_disable() uses smp_call_function_single() which doesn't fancy being used with IRQs disabled due to IPI deadlocks. Fix this by making it use the local __perf_counter_disable() call and teaching the counter_sched_out() code about pending disables as well. This should cover the case where a counter migrates before the pending queue gets processed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.244097721@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf: Rework/fix the whole read vs group stuffPeter Zijlstra2-83/+238
Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce PERF_FORMAT_GROUP to deal with group reads in a more generic way. This allows you to get group reads out of read() as well. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.117411814@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Fix swcounter context invariancePeter Zijlstra1-26/+18
perf_swcounter_is_counting() uses a lock, which means we cannot use swcounters from NMI or when holding that particular lock, this is unintended. The below removes the lock, this opens up race window, but not worse than the swcounters already experience due to RCU traversal of the context in perf_swcounter_ctx_event(). This also fixes the hard lockups while opening a lockdep tracepoint counter. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> Cc: Corey J Ashford <cjashfor@us.ibm.com> LKML-Reference: <1250149915.10001.66.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf report: Don't show unresolved DSOs and symbols when -S/-d is usedArnaldo Carvalho de Melo1-2/+3
We're interested in just those symbols/DSOs, so filter out the unresolved ones. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090812211957.GE3495@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf tools: Add a general option to enable raw sample recordsFrederic Weisbecker1-0/+5
While we can enable the perf sample records per tracepoint counter, we may also want to enable this option for every tracepoint counters to open, so that we don't need to add a :record flag for all of them. Add the -R, --raw-samples options for this purpose. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <1250152039-7284-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf tools: Add a per tracepoint counter attribute to get raw sampleFrederic Weisbecker2-1/+11
Add a new flag field while opening a tracepoint perf counter: -e tracepoint_subsystem:tracepoint_name:flags This is intended to be generic although for now it only supports the r[e[c[o[r[d]]]]] flag: ./perf record -e workqueue:workqueue_insertion:record ./perf record -e workqueue:workqueue_insertion:r will have the same effect: enabling the raw samples record for the given tracepoint counter. In the future, we may want to support further flags, separated by commas. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <1250152039-7284-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Provide hw_perf_counter_setup_online() APIsIngo Molnar2-1/+11
Provide weak aliases for hw_perf_counter_setup_online(). This is used by the BTS patches (for v2.6.32), but it interacts with fixes so propagate this upstream. (it has no effect as of yet) Also export perf_counter_output() to architecture code. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf list: Fix large list output by using the pagerArnaldo Carvalho de Melo1-1/+2
When /sys/kernel/debug is mounted the list can be imense, so use the pager like the other tools. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090812174459.GB3495@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13sh: fix i2c init order on ap325rxa V2Magnus Damm1-1/+1
Convert the AP325RXA board code to register devices at arch_initcall() time instead of device_initcall(). This fix unbreaks pcf8563 RTC driver support. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13sh: fix i2c init order on Migo-R V2Magnus Damm1-1/+1
Convert the Migo-R board code to register devices at arch_initcall() time instead of __initcall(). This fix unbreaks migor_ts touch screen driver support. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13sh: convert processor device setup functions to arch_initcall()Magnus Damm24-24/+24
Convert the processor platform device setup functions from __initcall() and sometimes device_initcall() to arch_initcall(). This makes sure that the platform devices are registered a bit earlier so the devices are available when drivers register using initcall levels earlier than device_initcall(). A good example is platform devices needed by i2c-sh_mobile.c which registers a bit earlier using subsys_initcall(). Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13md: allow upper limit for resync/reshape to be set when array is read-onlyNeilBrown1-0/+1
Normally we only allow the upper limit for a reshape to be decreased when the array not performing a sync/recovery/reshape, otherwise there could be races. But if an array is part-way through a reshape when it is assembled the reshape is started immediately leaving no window to set an upper bound. If the array is started read-only, the reshape will be suspended until the array becomes writable, so that provides a window during which it is perfectly safe to reduce the upper limit of a reshape. So: allow the upper limit (sync_max) to be reduced even if the reshape thread is running, as long as the array is still read-only. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: Properly remove excess drives after shrinking a raid5/6NeilBrown1-2/+9
We were removing the drives, from the array, but not removing symlinks from /sys/.... and not marking the device as having been removed. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: make sure a reshape restarts at the correct address.NeilBrown1-1/+1
This "if" don't allow for the possibility that the number of devices doesn't change, and so sector_nr isn't set correctly in that case. So change '>' to '>='. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: allow new reshape modes to be restarted in the middle.NeilBrown1-1/+20
md/raid5 doesn't allow a reshape to restart if it involves writing over the same part of disk that it would be reading from. This happens at the beginning of a reshape that increases the number of devices, at the end of a reshape that decreases the number of devices, and continuously for a reshape that does not change the number of devices. The current code is correct for the "increase number of devices" case as the critical section at the start is handled by userspace performing a backup. It does not work for reducing the number of devices, or the no-change case. For 'reducing', we need to invert the test. For no-change we cannot really be sure things will be safe, so simply require the array to be read-only, which is how the user-space code which carefully starts such arrays works. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md: never advance 'events' counter by more than 1.NeilBrown1-8/+5
When assembling arrays, md allows two devices to have different event counts as long as the difference is only '1'. This is to cope with a system failure between updating the metadata on two difference devices. However there are currently times when we update the event count by 2. This was done to keep the event count even when the array is clean and odd when it is dirty, which allows us to avoid writing common update to spare devices and so allow those spares to go to sleep. This is bad for the above reason. So change it to never increase by two. This means that the alignment between 'odd/even' and 'clean/dirty' might take a little longer to attain, but that is only a small cost. The spares will get a few more updates but that will still be spared (;-) most updates and can still go to sleep. Prior to this patch there was a small chance that after a crash an array would fail to assemble due to the overly large event count mismatch. Signed-off-by: NeilBrown <neilb@suse.de>
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