multipath keeps a separate device table which may be
more current than the built-in one.
So we should make sure to always call ->attach whenever
a multipath map with hardware handler is instantiated.
And we should call ->detach on removal, too.

[sekharan: update as per comments from agk]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch implements biovec merge function for crypt target.

If the underlying device has merge function defined, call it.
If not, keep precomputed value.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Remove max_sector restriction - merge function replaced it.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

This patch implements biovec merge function for linear target.

If the underlying device has merge function defined, call it.
If not, keep precomputed value.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Introduce a bvec merge function for device mapper devices
for dynamic size restrictions.

This code ensures the requested biovec lies within a single
target and then calls a target-specific function to check
against any constraints imposed by underlying devices.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Change snapshot per-module mempool to per-device mempool.

Per-module mempools could cause a deadlock if multiple
snapshot devices are stacked above each other.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Fix a race condition that returns incorrect data when a write causes an
exception to be allocated whilst a read is still in flight.

The race condition happens as follows:
* A read to non-reallocated sector in the snapshot is submitted so that the
  read is routed to the original device.
* A write to the original device is submitted. The write causes an exception
  that reallocates the block.  The write proceeds.
* The original read is dequeued and reads the wrong data.

This race can be triggered with CFQ scheduler and one thread writing and
multiple threads reading simultaneously.

(This patch relies upon the earlier dm-kcopyd-per-device.patch to avoid a
deadlock.)
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Whenever a snapshot read gets mapped through to the origin, track it in
a per-snapshot hash table indexed by chunk number, using memory allocated
from a new per-snapshot mempool.

We need to track these reads to avoid race conditions which will be fixed
by patches that follow.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Fix test for reinstate_path method before attempting to use it.
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: Julia Lawall <julia@diku.dk>

Return a specific error message if there are an invalid number of multipath
arguments.

This invalid command returns an "Unknown error" because the ti->error field is
not set

dmsetup create --table '0 2 multipath 0 0 1 1 round-robin 0 1 1 /dev/sdh' mpath0
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Rearrange struct dm_io.
Shrinks size from 40 -> 32 allowing more objects/slab.
Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

dm_dirty_log_{init,exit}() can now become static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

Free path selector if the arguments are invalid.

This command (note that it is invalid) causes reference leak on module
"dm_round_robin" and prevents the module from being removed.

dmsetup create --table '0 2 multipath 0 0 1 1 round-robin /dev/sdh' mpath0
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>

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: NNeilBrown <neilb@suse.de>

Open isn't the only thing that increments ->active.  e.g. reading
/proc/mdstat will increment it briefly.  So to avoid false positives
in testing for concurrent access, introduce a new counter that counts
just the number of times the md device it open.
Signed-off-by: NNeilBrown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeilBrown <neilb@suse.de>

This patch renames the array_size field of struct mddev_s to array_sectors
and converts all instances to use units of 512 byte sectors instead of 1k
blocks.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeilBrown <neilb@suse.de>

Also, change the type of the size parameter from unsigned long long to
sector_t and rename it to num_sectors.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeilBrown <neilb@suse.de>

The checks in overlaps() expect all parameters either in block-based
or sector-based quantities. However, its single caller passes two
rdev->data_offset arguments as well as two rdev->size arguments, the
former being sector counts while the latter are measured in 1K blocks.

This could cause rdev_size_store() to accept an invalid size from user
space. Fix it by passing only sector-based quantities to overlaps().
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeilBrown <neilb@suse.de>

 - used strict_strtoull in place of simple_strtoull
 - use my_mddev in place of rdev->mddev (they have the same value)
and more significantly,
 - don't adjust mddev->size to fit, rather reject changes which make
   rdev->size smaller than mddev->size

Adjusting mddev->size is a hangover from bind_rdev_to_array which
does a similar thing.  But it really is a better design to insist that
mddev->size is set as required, then the rdev->sizes are set to allow
for that.  The previous way invites confusion.
Signed-off-by: NNeilBrown <neilb@suse.de>

Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH
doesn't exist,just do not allow  hardware handlers to be used.

Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH
to be compiled in when SCSI_DH is a module.

[jejb: added comment for Kconfig syntax]
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Rename it to sb_start to make sure all users have been converted.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

As BLOCK_SIZE_BITS is 10 and

	MD_NEW_SIZE_SECTORS(2 * x) = 2 * NEW_SIZE_BLOCKS(x),

the return value of calc_dev_sboffset() doubles. Fix up all three
callers accordingly.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Number of sectors is the preferred unit for sizes of raid devices,
so change calc_dev_size() so that it returns this unit instead of
the number of 1K blocks.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Changing the internal representations of sizes of raid devices
from 1K blocks to sector counts (512B units) is desirable because
it allows to get rid of many divisions/multiplications and unnecessary
casts that are present in the current code.

This patch is a first step in this direction. It replaces the old
1K-based "size" argument of update_size() by "num_sectors" and
fixes up its two callers.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

do_md_stop check the number of active users before allowing the array
to be stopped.
Two problems:
  1/ it assumes the request is coming through an open file descriptor
     (via ioctl) so it allows for that.  This is not always the case.
  2/ it doesn't do the check it the array hasn't been activated.
     This is not good for cases when we use an inactive array to hold
     some devices in a container.
Signed-off-by: NNeil Brown <neilb@suse.de>

The current code copies a signed int from user space, converts it to
unsigned and passes the unsigned value to find_rdev_nr() which expects
a signed value. Simply pass the signed value from user space directly.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

If alloc_page() fails, ENOMEM is a more suitable error value
than EINVAL.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

The only caller of sb_equal() tests the return value against
zero, so it's OK to return the negated return value of memcmp().
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Remove the dubious attempt to prefer 'compute' over 'read'.  Not only is it
wrong given commit c337869d (md: do not compute parity unless it is on a failed
drive), but it can trigger a BUG_ON in handle_parity_checks5().

Cc: <stable@kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

- Remove superfluous parentheses.
- Make format string match the type of the variable that is printed.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

In case pers->run() succeeds but creating the bitmap fails, we
print an error message stating that pers->run() has failed.

Print this message only if pers->run() really failed.
Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

Signed-off-by: NAndre Noll <maan@systemlinux.org>
Signed-off-by: NNeil Brown <neilb@suse.de>

When devices are stacked, one device's merge_bvec_fn may need to perform
the mapping and then call one or more functions for its underlying devices.

The following bio fields are used:
  bio->bi_sector
  bio->bi_bdev
  bio->bi_size
  bio->bi_rw  using bio_data_dir()

This patch creates a new struct bvec_merge_data holding a copy of those
fields to avoid having to change them directly in the struct bio when
going down the stack only to have to change them back again on the way
back up.  (And then when the bio gets mapped for real, the whole
exercise gets repeated, but that's a problem for another day...)
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Milan Broz <mbroz@redhat.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>