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>
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: NeilBrown <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: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <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: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <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: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <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: NeilBrown <neilb@suse.de>
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>
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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil 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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil 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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil 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: Neil 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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil Brown <neilb@suse.de>
If alloc_page() fails, ENOMEM is a more suitable error value
than EINVAL.
Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil 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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil Brown <neilb@suse.de>
- Remove superfluous parentheses.
- Make format string match the type of the variable that is printed.
Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil 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: Andre Noll <maan@systemlinux.org>
Signed-off-by: Neil Brown <neilb@suse.de>
NeilBrown
Andre Noll
Neil Brown