kernel/linux.git/include/linux/raid, branch v2.6.28.3

md: use sysfs_notify_dirent to notify changes to md/dev-xxx/state

2008-10-21T02:25:28+00:00

The 'state' file for a device reports, for example, when the device has failed. Changes should be reported to userspace ASAP without the possibility of blocking on low-memory. sysfs_notify does have that possibility (as it takes a mutex which can be held across a kmalloc) so use sysfs_notify_dirent instead. Signed-off-by: NeilBrown

md: use sysfs_notify_dirent to notify changes to md/array_state

2008-10-21T02:25:21+00:00

Now that we have sysfs_notify_dirent, use it to notify changes to md/array_state. As sysfs_notify_dirent can be called in atomic context, we can remove the delayed notify and the MD_NOTIFY_ARRAY_STATE flag. Signed-off-by: NeilBrown

md: remove space after function name in declaration and call.

2008-10-13T00:55:12+00:00

Having function (args) instead of function(args) make is harder to search for calls of particular functions. So remove all those spaces. Signed-off-by: NeilBrown

md: Remove unnecessary #includes, #defines, and function declarations.

2008-10-13T00:55:12+00:00

A lot of cruft has gathered over the years. Time to remove it. Signed-off-by: NeilBrown

md: Convert remaining 1k representations in linear.c to sectors.

2008-10-13T00:55:12+00:00

This patch renames hash_spacing and preshift to spacing and sector_shift respectively with the following change of semantics: Case 1: (sizeof(sector_t) <= sizeof(u32)). ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In this case, we have sector_shift = preshift = 0 and spacing = 2 * hash_spacing. Hence, the index for the hash table which is computed by the new code in which_dev() as sector / spacing equals the old value which was (sector/2) / hash_spacing. Note also that the value of nb_zone stays the same because both sz and base double. Case 2: (sizeof(sector_t) > sizeof(u32)). ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (aka the shifting dance case). Here we have sector_shift = preshift + 1 and spacing = 2 * hash_spacing during the computation of nb_zone and curr_sector, but spacing = hash_spacing in which_dev() because in the last hunk of the patch for linear.c we shift down conf->spacing (= 2 * hash_spacing) by one more bit than in the old code. Hence in the computation of nb_zone, sz and base have the same value as before, so nb_zone is not affected. Also curr_sector in the next hunk stays the same. In which_dev() the hash table index is computed as (sector >> sector_shift) / spacing In view of sector_shift = preshift + 1 and spacing = hash_spacing, this equals ((sector/2) >> preshift) / hash_spacing which is the value computed by the old code. Signed-off-by: Andre Noll Signed-off-by: NeilBrown

md: linear: Represent dev_info->size and dev_info->offset in sectors.

2008-10-13T00:55:12+00:00

Rename them to num_sectors and start_sector which is more descriptive. Signed-off-by: Andre Noll Signed-off-by: NeilBrown

md: delay notification of 'active_idle' to the recovery thread

2008-07-23T20:09:48+00:00

sysfs_notify might sleep, so do not call it from md_safemode_timeout. Signed-off-by: Dan Williams

md: Protect access to mddev->disks list using RCU

2008-07-21T07:05:25+00:00

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

md: only count actual openers as access which prevent a 'stop'

2008-07-21T07:05:25+00:00

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

md: linear: Make array_size sector-based and rename it to array_sectors.

2008-07-21T07:05:25+00:00

Signed-off-by: Andre Noll Signed-off-by: NeilBrown