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  1. 21 Jul, 2008 7 commits
    • NeilBrown's avatar
      md: Protect access to mddev->disks list using RCU · 4b80991c
      NeilBrown authored 
      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: default avatarNeilBrown <neilb@suse.de>
      4b80991c
    • NeilBrown's avatar
      md: only count actual openers as access which prevent a 'stop' · f2ea68cf
      NeilBrown authored 
      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: default avatarNeilBrown <neilb@suse.de>
      f2ea68cf
    • Andre Noll's avatar
      md: linear: Make array_size sector-based and rename it to array_sectors. · d6e22150
      Andre Noll authored 
      Signed-off-by: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      d6e22150
    • Andre Noll's avatar
      md: Make mddev->array_size sector-based. · f233ea5c
      Andre Noll authored 
      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: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      f233ea5c
    • Andre Noll's avatar
      md: Make super_type->rdev_size_change() take sector-based sizes. · 15f4a5fd
      Andre Noll authored 
      Also, change the type of the size parameter from unsigned long long to
sector_t and rename it to num_sectors.
Signed-off-by: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      15f4a5fd
    • Andre Noll's avatar
      md: Fix check for overlapping devices. · d07bd3bc
      Andre Noll authored 
      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: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      d07bd3bc
    • Neil Brown's avatar
      md: Tidy up rdev_size_store a bit: · d7027458
      Neil Brown authored 
       - 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: default avatarNeilBrown <neilb@suse.de>
      d7027458
  3. 11 Jul, 2008 13 commits
  5. 10 Jul, 2008 20 commits