Alexander Viro [Mon, 22 Jul 2002 03:01:53 +0000 (20:01 -0700)]
[PATCH] Fix dcache deadlock introduced by previous fix
So the fix for our problems is:
a) in fs/namei.c replace d_unhash() with a safe version.
b) in fs/nfs/dir.c replace d_drop(dentry) in beginning of nfs_unlink()
with list_del_init(&dentry->d_hash);
Alexander Viro [Sun, 21 Jul 2002 13:26:17 +0000 (06:26 -0700)]
[PATCH] fix for nfs_unlink and vfs_unlink
Ugh. nfs_unlink() is actually racy as hell - look what happens if
we enter it with ->d_count == 1, see that nfs_sillyrename() doesn't
need to do anything and call nfs_safe_remove(). In the meanwhile
somebody does dcache lookup (without going into NFS code - plain
and simple cache hit) and increments ->d_count. nfs_safe_remove()
decides that something is very rotten and fails.
AFAICS we should take the test for ->d_count + d_drop if it's 1
under dcache_lock (and in one place). Comments?
Proposed fix follows:
* dget/dput killed in vfs_unlink() (safely)
* nfs_unlink() starts with check for ->d_count (under dcache_lock)
* if it's > 1 - sillyrename
* if it is 1 - immediately unhash, then drop dcache_lock.
after that we do as in old variant, except that
rehashing is done in nfs_unlink() and only if there
was an error - if there was none we simply leave
d_delete() to vfs_unlink().
Russell King [Sun, 21 Jul 2002 09:39:46 +0000 (02:39 -0700)]
[PATCH] Serial driver stuff
The serial layer is restructured to allow less code duplication (and
hence bug duplication) across various serial drivers. Since ARM adds
six extra serial drivers, maintaining six copies of serial.c was not
my idea of fun.
Therefore, we've ended up with a core serial driver, which knows about
the interactions with the tty layer, and low-level hardware drivers,
which know all about the hardware. The interface between the two is
described in "Documentation/serial/driver".
This patch completely removes the old serial.c driver and its associated
configuration options, as you requested at KS2002. We keep a certain
amount of configuration compatibility with the per-architecture serial.h
file for the moment; this *will* be killed in the next round of patches.
The biggest user of this is x86, and since I don't have an x86 box to
test this stuff on, I think the changes are best kept separate.
This is a massive cleanup of the IRQ subsystem. It's losely based on
Linus' original idea and DaveM's original implementation, to fold our
various irq, softirq and bh counters into the preemption counter.
with this approach it was possible:
- to remove the 'big IRQ lock' on SMP - on which sti() and cli() relied.
- to streamline/simplify arch/i386/kernel/irq.c significantly.
- to simplify the softirq code.
- to remove the preemption count increase/decrease code from the lowlevel
IRQ assembly code.
- to speed up schedule() a bit.
Global sti() and cli() is gone forever on SMP, there is no more globally
synchronizing irq-disabling capability. All code that relied on sti()
and cli() and restore_flags() must use other locking mechanisms from now
on (spinlocks and __cli()/__sti()).
obviously this patch breaks massive amounts of code, so only limited
.configs are working at the moment (UP is expected to be unaffected, but
SMP will require various driver updates).
The patch was developed and tested on SMP systems, and while the code is
still a bit rough in places, the base IRQ code appears to be pretty
robust and clean.
while it boots already so the worst is over, there is lots of work left:
eg. to fix the serial layer to not use cli()/sti() and bhs ...
Alexander Viro [Sun, 21 Jul 2002 03:49:31 +0000 (20:49 -0700)]
[PATCH] jffs kdev_t cleanups
In the /proc/fs/jffs/* code we switch to passing number of mtd device
(as an integer) instead of messing with kdev_t (which would always be
mk_kdev(MTD_BLOCK_MAJOR, device_number) anyway).
Alexander Viro [Sun, 21 Jul 2002 03:48:41 +0000 (20:48 -0700)]
[PATCH] paride cleanup and fixes
somewhat related to the above - drivers/block/paride/* switched to
module_init()/module_exit(), pd.c taught to use LBA if disks support
it (needed for paride disks >8Gb; change is fairly trivial and I've
got 40Gb one ;-)
Alexander Viro [Sun, 21 Jul 2002 03:48:09 +0000 (20:48 -0700)]
[PATCH] partition handling locking cleanups
Horrors with open/reread_partition exclusion are starting to get fixed.
It's not the final variant, but at least we are getting the logics into
one place; switch to final variant will happen once we get per-disk
analog of gendisks. New fields - ->bd_part_sem and ->bd_part_count.
The latter counts the amount of opened partitions. The former protects
said count _and_ is held while we are rereading partition tables.
Helpers - dev_part_lock()/dev_part_unlock() (currently taking kdev_t; that
will change pretty soon). No more ->open() and ->release() for partitions,
all that logics went to generic code. Lock hierachy is currently messy:
->bd_sem for partitions -> ->bd_part_sem -> ->bd_sem for entire disks
Ugly, but that'll go away and to get the final variant of locking right
now would take _really_ big patch - with a lot of steps glued together.
The damn thing is large as it is...
Alexander Viro [Sun, 21 Jul 2002 03:47:53 +0000 (20:47 -0700)]
[PATCH] block device size cleanups
for partitioned devices we use ->nr_sect to find the size; blk_size[] is
still used for things like floppy.c, etc.; that will go away later.
There was only one place (do_open()) that needed it - the rest uses
->bd_inode->i_size now. So blkdev_size_in_bytes() is gone - it's
expanded in its only caller. Same place (do_open()) finds the partition
offset and stores it in new field ->bd_offset. As the result, call of
get_gendisk() is gone from the IO path - in blk_partition_remap() we
just add ->bd_offset.
Additionally, we take driver probing (get_blkfops()) outside of ->bd_sem
(again, do_open()) - that will allow to kill ad-hackery in check_partitions()
(opening bdev by hand).
Alexander Viro [Sun, 21 Jul 2002 03:47:38 +0000 (20:47 -0700)]
[PATCH] partition parsing cleanup
struct gendisk and partition parsers divorced; all these parsers (IBM style,
disklabel, etc.) just fill the structure they get from check_partitions().
Actual setting the things up (filling hd_struct arrays, telling RAID that
we had found partitions worth a look, etc.) is taken into check_partitions()
and done only when we are done with parsing. Parsers don't know (or care)
what majors/minors they are dealing with; that knowledge also went to
check_partitions().
Andrew Morton [Fri, 19 Jul 2002 04:11:11 +0000 (21:11 -0700)]
[PATCH] readahead optimisations
Been looking at a workload which involves several processes which seek
around and read from a large file. There are a few problems:
generic_file_lseek is bouncing i_sem around like mad, and readahead is
doing lots of pointless pagecache probing.
This patch addresses readahead.
Presumably the change will be larger on machines which have higher
bandwidth memory than my test box, of which there are many.
This patch teaches readahead to detect the situation where no IO is
actually being performed as a result of its actions. Now, we don't
want to sacrifice IO efficiency to save a bit of CPU, so the code is
very cautious. But eventually, after some tens of consecutive
readahead attempts were found to perform no I/O at all, readahead will
turn itself off.
readahead will be turned on again when either generic_file_read() or
filemap_nopage() get a pagecache miss. The function
handle_ra_thrashing() has been renamed to handle_ra_miss() to reflect
its widened role.
A performance bug in page_cache_readround() was fixed - if
ra->next_size is zero, that function needs to leave it well alone,
because next_size==0 is a magic value meaning that the file has just
been opened and that readahead needs to get aggressive. This change
makes a `make dep' run at the same speed as in the 2.4 kernel. It used
to take 4x as long...
`make dep' is an interesting test because it uses mmap to read the files.
Andrew Morton [Fri, 19 Jul 2002 04:10:57 +0000 (21:10 -0700)]
[PATCH] writeback scalability improvements
The kernel has a number of problems wrt heavy write traffic to multiple
spindles. What keeps on happening is that all processes which are
responsible for writeback get blocked on one of the queues and all the
others fall idle.
This happens in the balance_dirty_pages() path (balance_dirty() in 2.4)
and in the page reclaim code, when a dirty page is found on the LRU.
The latter is particularly bad because it causes "innocent" processes
to be suspended for long periods due to the activity of heavy writers.
The general idea is: the primary resource for writeback should be the
process which is dirtying memory. The secondary resource is the
pdflush pool (although this is mainly for providing async writeback in
the presence of light-moderate loads). Add the final
oh-gee-we-screwed-up resource for writeback is a caller to
shrink_cache().
This patch addresses the balance_dirty_pages() path. This code was
initially modelled on the 2.4 writeback scheme: throttled processes
writeback all data regardless of its queue. Instead, the patch changes
it so that the balance_dirty_pages() caller only writes back pages
which are dirty against the queue which that caller just dirtied.
So the effect is a better allocation of writeback resources across the
queues and increased parallelism.
The per-queue writeback is implemented by using
mapping->backing_dev_info as a search key during the walk across the
superblocks and inodes.
The patch also fixes an initialisation problem in
block_dev.c:do_open(): it was setting up the blockdev's
mapping->backing_dev_info too early, before the queue has been
identified.
Generally, this patch doesn't help much, because of the stalls in the
page allocator. I have a patch which mostly fixes that up, and taken
together the kernel is achieving almost platter speed against six
spindles, but only when the system has a small amount of memory. More
work is needed there.
Andrew Morton [Fri, 19 Jul 2002 04:10:43 +0000 (21:10 -0700)]
[PATCH] remove add_to_page_cache_unique()
A tasty patch from Hugh Dickens. radix_tree_insert() fails if something
was already present at the target index, so that error can be
propagated back through add_to_page_cache(). Hence
add_to_page_cache_unique() is obsolete.
Hugh's patch removes add_to_page_cache_unique() and cleans up a bunch of
stuff.
Andrew Morton [Fri, 19 Jul 2002 04:09:30 +0000 (21:09 -0700)]
[PATCH] O_DIRECT open check
Updated forward-port of Aodrea's O_DIRECT open() checks. If the user
asked for O_DIRECT and the inode has no mapping or no a_ops then fail
the open up-front.
Andrew Morton [Fri, 19 Jul 2002 04:09:17 +0000 (21:09 -0700)]
[PATCH] VM instrumentation
A patch from Rik which adds some operational statitics to the VM.
In /proc/meminfo:
PageTables: Amount of memory used for process pagetables
PteChainTot: Amount of memory allocated for pte_chain objects
PteChainUsed: Amount of memory currently in use for pte chains.
In /proc/stat:
pageallocs: Number of pages allocated in the page allocator
pagefrees: Number of pages returned to the page allocator
(These can be used to measure the allocation rate)
pageactiv: Number of pages activated (moved to the active list)
pagedeact: Number of pages deactivated (moved to the inactive list)
pagefault: Total pagefaults
majorfault: Major pagefaults
pagescan: Number of pages which shrink_cache looked at
pagesteal: Number of pages which shrink_cache freed
pageoutrun: Number of calls to try_to_free_pages()
allocstall: Number of calls to balance_classzone()
Rik will be writing a userspace app which interprets these things.
The /proc/meminfo stats are efficient, but the /proc/stat accumulators
will cause undesirable cacheline bouncing. We need to break the disk
statistics out of struct kernel_stat and make everything else in there
per-cpu. If that doesn't happen in time for 2.6 then we disable
KERNEL_STAT_INC().
Andrew Morton [Fri, 19 Jul 2002 04:09:02 +0000 (21:09 -0700)]
[PATCH] avoid allocating pte_chains for unshared pages
Patch from David McCracken. It is an optimisation to the rmap
pte_chains.
In the common case where a page is mapped by only a single pte, we
don't need to allocate a pte_chain structure. Just make the page's
pte_chain pointer point straight at that pte and flag this with
PG_direct.
Andrew Morton [Fri, 19 Jul 2002 04:08:49 +0000 (21:08 -0700)]
[PATCH] leave truncate's orphaned pages on the LRU
Fix to the page reclaim code from Rik.
Anonymous pages which have buffers arise when
truncate_complete_page()'s call to ->releasepage() failed. Those pages
may still be mapped into process address spaces.
We should not remove them from the LRU, because that makes them
unswappable and they hang around until process exit.
Andrew Morton [Fri, 19 Jul 2002 04:08:35 +0000 (21:08 -0700)]
[PATCH] minimal rmap
This is the "minimal rmap" patch, writen by Rik, ported to 2.5 by Craig
Kulsea.
Basically,
before: When the page reclaim code decides that is has scanned too many
unreclaimable pages on the LRU it does a scan of process virtual
address spaces for pages to add to swapcache. ptes pointing at the
page are unmapped as the scan proceeds. When all ptes referring to a
page have been unmapped and it has been written to swap the page is
reclaimable.
after: When an anonymous page is encountered on the tail of the LRU we
use the rmap to see if it hasn't been referenced lately. If so then
add it to swapcache. When the page is again encountered on the LRU, if
it is still unreferenced then try to unmap all ptes which refer to it
in one hit, and if it is clean (ie: on swap) then free it.
The rest of the VM - list management, the classzone concept, etc
remains unchanged.
There are a number of things which the per-page pte chain could be
used for. Bill Irwin has identified the following.
(1) page replacement no longer goes around randomly unmapping things
(2) referenced bits are more accurate because there aren't several ms
or even seconds between find the multiple pte's mapping a page
(3) reduces page replacement from O(total virtually mapped) to O(physical)
(4) enables defragmentation of physical memory
(5) enables cooperative offlining of memory for friendly guest instance
behavior in UML and/or LPAR settings
(6) demonstrable benefit in performance of swapping which is common in
end-user interactive workstation workloads (I don't like the word
"desktop"). c.f. Craig Kulesa's post wrt. swapping performance
(7) evidence from 2.4-based rmap trees indicates approximate parity
with mainline in kernel compiles with appropriate locking bits
(8) partitioning of physical memory can reduce the complexity of page
replacement searches by scanning only the "interesting" zones
implemented and merged in 2.4-based rmap
(9) partitioning of physical memory can increase the parallelism of page
replacement searches by independently processing different zones
implemented, but not merged in 2.4-based rmap
(10) the reverse mappings may be used for efficiently keeping pte cache
attributes coherent
(11) they may be used for virtual cache invalidation (with changes)
(12) the reverse mappings enable proper RSS limit enforcement
implemented and merged in 2.4-based rmap
The code adds a pointer to struct page, consumes additional storage for
the pte chains and adds computational expense to the page reclaim code
(I measured it at 3% additional load during streaming I/O). The
benefits which we get back for all this are, I must say, theoretical
and unproven. If it has real advantages (or, indeed, disadvantages)
then why has nobody demonstrated them?
There are a number of things remaining to be done:
1: Demonstrate the above advantages.
2: Make it work with pte-highmem (Bill Irwin is signed up for this)
3: Don't add pte_chains to non-shared pages optimisation (Dave McCracken's
patch does this)
4: Move the pte_chains into highmem too (Bill, I guess)
5: per-cpu pte_chain freelists (Rik?)
6: maybe GC the pte_chain backing pages. (Seems unavoidable. Rik?)
7: multithread the page reclaim code. (I have patches).
8: clustered add-to-swap. Not sure if I buy this. anon pages are
often well-ordered-by-virtual-address on the LRU, so it "just
works" for benchmarky loads. But there may be some other loads...
9: Fix bad IO latency in page reclaim (I have lame patches)
10: Develop tuning tools, use them.
11: The nightly updatedb run is still evicting everything.
Stuart MacDonald [Fri, 19 Jul 2002 03:46:43 +0000 (20:46 -0700)]
[PATCH] USB: usbserial.c fixup
create_serial, get_free_serial and usb_serial_probe all do pretty much
the same thing. I'd like to reorg this into create_serial does all the
alloc and most of the setup, and get_free_serial just fills in the
MAGIC.
There's currently a memory leak: if create_serial is called at probe
time or calc_ports time, and then get_free_serial returns NULL because
the table has no entries left, that usb_serial struct is leaked.
get_free_serial doesn't check properly for free slots. The middle loop
doesn't terminate when the end of the table is reached, although the
assignment loop later does. The effect is that stuff past the end of
the table is allowed to decide if there's free space or not, and
occasionally it'll say "yes" and then the assignment loop will only
allocate slots up to the end of the table, preventing memory
scribbling.
I haven't fixed any of this just yet because I'm not sure what the
intended behaviour is. Should get_free_serial allocate as many slots
as possible, or just be all or nothing? Similarly, I don't see a
problem with calling create_serial early in usb_serial_probe, and
removing the alloc code from get_free_serial; this would fix the leak.
Ah heck, here's a patch. This is what I think things should look like.
get_free_serial is all or none, the leak is fixed and create_serial
does all the allocation.
Name: Designated initializers for drivers/usb
Author: Rusty Russell
Status: Trivial
D: The old form of designated initializers are obsolete: we need to
D: replace them with the ISO C forms before 2.6. Gcc has always supported
D: both forms anyway.
Martin Dalecki [Fri, 19 Jul 2002 02:26:04 +0000 (19:26 -0700)]
[PATCH] 2.5.26 IDE 99
Most noticable in the patch:
1. we handle IRQ sharing now better then ever
2. survives quite a lot of testing by few people. Forexample
cat /dev/hdb > /dev/null, where /dev/hdb contains a CD-ROM
with a big cratch on the surface making sure it's broken :-).
it's BTW. amanzing how wide the cratch had to be until errors
ocurred.
3. Doesn't play with rq_rdev and friends
Fri Jul 12 05:04:32 CEST 2002 ide-clean-99
- Push nIEN disabling down at the place where we are finished with a particular
request.
- First round of command line parser cleanups by Gerald Champagne.
- Unfold the drive eviction functions in do_request(). This allowed us to
realize that we don't have to re-get the major/minor numbers of the device we
are action on from the raw device field of the currently running request. One
significant place less in kernel where major/minor data gets manipulated.
- Move the big IDE_BUSY loop out of do_request to do_ide_request(). This makes
us realize that we don't have to clear the IDE_BUSY bit just before
reentering do_request to look for more requests still pending on the queue
and set it immediately again.
This is fixing a tinny race on the code path from IRQ or timer function,
where we had a tinny window between the clearing of the IDE_BUSY bit and
reentering the request queue for completely unrelated requests to come in to
our way.
- Don't return any value in do_reset1(). It's always ATA_OP_CONTINUES. Split it
up in to two functions one for disks (well in fact channels) and one for
ATAPI devices. It turns out that they can be moved to the places where they
are used to clarify the code flow. The only function remaining is
do_reset_channel() now.
- Duplicate code from ide_do_drive_code explicitely in ide_raw_taskfile().
Simplify ide_raw_taskfile() thereafter. Realize that ide_do_drive_cmd()
is now only used by ATAPI devices. Move it therefore to atapi.c.
- Do busy polling for ATAPI reset operations. This is much safer then the
previous timer games played there. It simply doesn't make sense to give the
bus up during such a subtile operation. We don't have to disable IRQs here as
well, since we are already under the protection of the do_request mechanisms.
(Well hopefully...)
- Remove no longer used reset_poll() function. poll_timeout and friends are now
used only in pdc4030 code. Those function where not called from IRQ context
but they where set as handlers and not as expiry functions.
- Return ATA_OP_CONTINUES instead of ATA_OP_FINISHED in ata_error(), to signal
that we are willing to retry the operation until the maximal number of retry
attempts is exceeded. Returning ATA_OP_FINISHED without prior end_request()
hangs the system.
- Apply trivia from DJ patch set.
- Apply small configuration fix to ide-pci.c from Muli Ben-Yehuda.
- Feed add_blkdev_randomness with information we already have in struct
ata_channel *ch->major, instead of using the major(macro) on the request in
question.
- Make ide_raw_taskfile use the same request submission mechanism as
tcq_invalidate_queue(). Something similar would be ideal for ioctl() code as
well.
- Implement actual device reset. Realize that the recalibration procedure is
doomed by the standard. Don't try to recover by recalibrating devices
therefore -just our retry mechanism should work in those cases. And suddenly
the error handling code is IRQ safe.
- Reinvent the ATA reset operation, since it is apparently needed. We still
have to do the whole transfer timing reconfiguration there.
- Move drive_is_ready(), which is in reality an attempt to check for IRQ
requesters without clearing the IRQ line, over to the place where it belongs:
device.c, which is the direct device access abstraction place. Rename it to
ata_status_irq() to prevent global name space pollution.
- Updates to the pdc202xxx host chip controller setup code by Bart³omiej
¯o³nierkiewicz:
Forward port 2.4 patch by Hank Yang from Promise:
- Add PDC20271 support
- Disable LBA48 support on PDC20262
- Fix ATAPI UDMA port value
- Add new quirk drive
- Adjust timings for all drives when using ATA133
- Update pdc202xx_reset() waiting time
- Mark TCQ as dangerous and add some bits about it to the help.
- Add some missing exports.
- Some small ide-scsi.c host allocation fixes by sullivan.
Neil Brown [Fri, 19 Jul 2002 02:12:13 +0000 (19:12 -0700)]
[PATCH] MD - Get rid of dev in rdev and use bdev exclusively.
Get rid of dev in rdev and use bdev exclusively.
There is an awkwardness here in that userspace sometimes
passed down a dev_t (e.g. hot_add_disk) and sometime
a major and a minor (e.g. add_new_disk). Should we convert
both to kdev_t as the uniform standard....
That is what was being done but it seemed very clumsy and
things were gets converted back and forth a lot.
As bdget used a dev_t, I felt safe in staying with dev_t once I
had one rather than converting to kdev_t and back.
Neil Brown [Fri, 19 Jul 2002 02:11:45 +0000 (19:11 -0700)]
[PATCH] MD - Remove the sb from the mddev
Remove the sb from the mddev
Now that al the important information is in mddev, we don't need
to have an sb off the mddev. We only keep the per-device ones.
Previously we determined if "set_array_info" had been run byb checking
mddev->sb. Now we check mddev->raid_disks on the assumption that
any valid array MUST have a non-zero number of devices.
Neil Brown [Fri, 19 Jul 2002 02:11:27 +0000 (19:11 -0700)]
[PATCH] MD - Remove dependance on superblock
Remove dependance on superblock
All the remaining field of interest in the superblock
get duplicated in the mddev struture and this is treated as
authoritative. The superblock gets completely generated at
write time, and all useful information extracted at read time.
This means that we can slot in different superblock formats
without affecting the bulk of the code.
Neil Brown [Fri, 19 Jul 2002 02:10:16 +0000 (19:10 -0700)]
[PATCH] MD - Don't maintain disc status in superblock.
Don't maintain disc status in superblock.
The state is now in rdev so we don't maintain it
in superblock any more.
We also nolonger test content of superblock for
disk status
mddev->spare is now an rdev and not a superblock fragment.
Neil Brown [Fri, 19 Jul 2002 02:09:07 +0000 (19:09 -0700)]
[PATCH] MD - Improve handling of spares in md
Improve handling of spares in md
- hot_remove_disk is given the raid_disk rather than descriptor number
so that it can find the device in internal array directly, no search.
- spare_inactive now uses mddev->spare->raid_disk instead of
mddev->spare->number so it can find the device directly without searching
- spare_write does not need number. It can use mddev->spare->raid_disk as above.
- spare_active does not need &mddev->spare. It finds the descriptor directly
and fixes it without this pointer
Neil Brown [Fri, 19 Jul 2002 02:08:42 +0000 (19:08 -0700)]
[PATCH] MD - Set desc_nr more sanely.
Set desc_nr more sanely.
Currently rdev->desc_nr is set in sync_sbs which is typcially
called just before writing out the superblocks, which is an
odd place to set it.
It is also called when a new disk is added (which is sane) and
when an old disc is imported ... which is quesitonable.
With this patch it is set when a new disk is added, and when
the superblocks are being analysed, which makes lots of sense.
MULTIPATH is particularly an issue here. The old code tried
to figure the desc_nr for an rdev by matching device numbers in
the superblock. This doesn't make a lot of sense as
device numbers can change. Now MULTIPATH components
get sequential desc_nrs.
Neil Brown [Fri, 19 Jul 2002 02:08:28 +0000 (19:08 -0700)]
[PATCH] MD - Move md_update_sb calls
Move md_update_sb calls
When a change which requires a superblock update happens
at interrupt time, we currently set a flag (sb_dirty) and
wakeup to per-array thread (raid1/raid5d/multipathd) to
do the actual update.
This patch centralises this. The sb_update is now done
by the mdrecoveryd thread. As this is always woken up after
the error handler is called, we don't need the call to wakeup
the local thread any more.
With this, we don't need "md_update_sb" to lock the array
any more and only use __md_update_sb which is local to md.c
So we rename __md_update_sb back to md_update_sb and stop
exporting it.
Neil Brown [Fri, 19 Jul 2002 02:08:13 +0000 (19:08 -0700)]
[PATCH] MD - Pass the correct bdev to md_error
Pass the correct bdev to md_error
After a call to generic_make_request, bio->bi_bdev can have changed
(e.g. by a re-mapped like raid0). So we cannot trust it for reporting
the source of an error. This patch takes care to find the correct
bdev.
Neil Brown [Fri, 19 Jul 2002 02:07:59 +0000 (19:07 -0700)]
[PATCH] MD - Rdev list cleanups.
Rdev list cleanups.
An "rdev" can be on three different lists.
- the list of all rdevs
- the list of pending rdevs
- the list of rdevs for a given mddev
The first list is now only used to list "unused" devices in
/proc/mdstat, and only pending rdevs can be unused, so this list
isn't necessary.
An rdev cannot be both pending and in an mddev, so we know rdev will
only be on one list at at time.
This patch discards the all_raid_disks list, and changes the
pending list to use "same_set" in the rdev. It also changes
/proc/mdstat to iterate through pending devices, rather than through
all devices.
So now an rdev is only on one list, either the pending list
or the list of rdevs for a given mddev. This means that
ITERATE_RDEV_GENERIC doesn't need to be told which field,
to walk down: there is ony one.
Neil Brown [Fri, 19 Jul 2002 02:07:44 +0000 (19:07 -0700)]
[PATCH] MD - Get rid of find_rdev_all
Get rid of find_rdev_all
find_rdev_all is now only used to check if a device is already
used in an md array.
We change lock_rdev so that it claims the bdev for
the specific rdev rather than for rdevs in general.
Now lock_rdev will check if the bdev is inuse by another array
or not, so the find_rdev_all check isn't needed and is removed,
along with find_rdev_all itself.
We also make sure that the error code from lock_rdev is
propagated up properly.
Neil Brown [Fri, 19 Jul 2002 02:07:27 +0000 (19:07 -0700)]
[PATCH] MD - Use symbolic names for multipath (-4) and linear (-1)
Use symbolic names for multipath (-4) and linear (-1)
Also, a variable called "level" was being used to store a
"level" and a "personality" number. This is potentially
confusing, so it is now two variables.
Neil Brown [Fri, 19 Jul 2002 02:07:14 +0000 (19:07 -0700)]
[PATCH] MD - Don't "analyze_sb" when creating new array.
Don't "analyze_sb" when creating new array.
When creating a new array (and we have an mddev->sb),
don't both to analyze the superblocks. There is no point.
Also, these means we always allocate the array sb in
analyze_sbs, rather than conditionally.
Neil Brown [Fri, 19 Jul 2002 02:07:01 +0000 (19:07 -0700)]
[PATCH] MD - Embed bio in mp_bh rather than separate allocation.
Embed bio in mp_bh rather than separate allocation.
multipath currently allocates an mp_bh and a bio for each
request. With this patch, the bio is made to be part of the
mp_bh so there is only one allocation, and it from a private
pool (the bio was allocated from a shared pool).
Also remove "remaining" and "cmd" from mp_bh which aren't used.
And remove spare (unused) from multipath_private_data.
Neil Brown [Fri, 19 Jul 2002 02:06:18 +0000 (19:06 -0700)]
[PATCH] MD - Remove dead consistancy checking code from multipath.
Remove dead consistancy checking code from multipath.
This "consistancy_check" is carried over from raid1 on which multipath
was based, and was not used in raid1 and has since been removed. Now
it gets removed from multipath too.
Neil Brown [Fri, 19 Jul 2002 02:06:03 +0000 (19:06 -0700)]
[PATCH] MD - Remove bdput calls from raid personalities.
Remove bdput calls from raid personalities.
Some of the md personalities currently hold a counted reference
on a bdev. This is not necessary as the main md module will always
hold a counted reference in the rdev.
This patch removes the code to take and drop these unnecessary
references.
The appended patch fixes a typo in net/sunrpc/xprt.c: We want to
ensure that we play safe, and only increment the UDP congestion window
when we have successfully transmitted a full frame of data.
In addition, we should perhaps still 'slow start' the UDP congestion
code rather than assuming that we can immediately fire off 8
requests. IOW revert the value of RPC_INITCWND.
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