linux/drivers/md/bitmap.c, branch v2.6.37

md: unplug writes to external bitmaps.

2010-10-29T05:40:32Z

When writing to an 'external' bitmap we don't currently unplug the device before waiting, so we can get a 3msec delay each time; So use REQ_UNPLUG to force and unplug. Signed-off-by: NeilBrown

md: change type of first arg to sync_page_io.

2010-10-28T06:36:11Z

Currently sync_page_io takes a 'bdev'. Every caller passes 'rdev->bdev'. We will soon want another field out of the rdev in sync_page_io, So just pass the rdev instead of the bdev out of it. Signed-off-by: NeilBrown

md: use sector_t in bitmap_get_counter

2010-10-28T06:32:26Z

bitmap_get_counter returns the number of sectors covered by the counter in a pass-by-reference variable. In some cases this can be very large, so make it a sector_t for safety. Signed-off-by: NeilBrown

md: check return code of read_sb_page

2010-10-07T01:02:50Z

Function read_sb_page may return ERR_PTR(...). Check for it. Signed-off-by: Vasiliy Kulikov Cc: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: NeilBrown

md: resolve confusion of MD_CHANGE_CLEAN

2010-08-30T08:06:21Z

MD_CHANGE_CLEAN is used for two different purposes and this leads to confusion. One of the purposes is largely mirrored by MD_CHANGE_PENDING which is not used for anything else, so have MD_CHANGE_PENDING take over that purpose fully. The two purposes are: 1/ tell md_update_sb that an update is needed and that it is just a clean/dirty transition. 2/ tell user-space that an transition from clean to dirty is pending (something wants to write), and tell te kernel (by clearin the flag) that the transition is OK. The first purpose remains wit MD_CHANGE_CLEAN, the second is moved fully to MD_CHANGE_PENDING. This means that various places which conditionally set or cleared MD_CHANGE_CLEAN no longer need to be conditional. Signed-off-by: NeilBrown

md/bitmap: separate out loading a bitmap from initialising the structures.

2010-07-26T03:21:34Z

dm makes this distinction between ->ctr and ->resume, so we need to too. Also get the new bitmap_load to clear out the bitmap first, as this is most consistent with the dm suspend/resume approach Signed-off-by: NeilBrown

md/bitmap: prepare for storing write-intent-bitmap via dm-dirty-log.

2010-07-26T03:21:34Z

This allows md/raid5 to fully work as a dm target. Normally md uses a 'filemap' which contains a list of pages of bits each of which may be written separately. dm-log uses and all-or-nothing approach to writing the log, so when using a dm-log, ->filemap is NULL and the flags normally stored in filemap_attr are stored in ->logattrs instead. Signed-off-by: NeilBrown

md/bitmap: optimise scanning of empty bitmaps.

2010-07-26T03:21:32Z

A bitmap is stored as one page per 2048 bits. If none of the bits are set, the page is not allocated. When bitmap_get_counter finds that a page isn't allocate, it just reports that one bit work of space isn't flagged, rather than reporting that 2048 bits worth of space are unflagged. This can cause searches for flagged bits (e.g. bitmap_close_sync) to do more work than is really necessary. So change bitmap_get_counter (when creating) to report a number of blocks that more accurately reports the range of the device for which no counter currently exists. Signed-off-by: NeilBrown

md/bitmap: clean up plugging calls.

2010-07-26T03:21:32Z

1/ use md_unplug in bitmap.c as we will soon be using bitmaps under arrays with no queue attached. 2/ Don't bother plugging the queue when we set a bit in the bitmap. The reason for this was to encourage as many bits as possible to get set before we unplug and write stuff out. However every personality already plugs the queue after bitmap_startwrite either directly (raid1/raid10) or be setting STRIPE_BIT_DELAY which causes the queue to be plugged later (raid5). Signed-off-by: NeilBrown

md/bitmap: reduce dependence on sysfs.

2010-07-26T03:21:31Z

For dm-raid45 we will want to use bitmaps in dm-targets which don't have entries in sysfs, so cope with the mddev not living in sysfs. Signed-off-by: NeilBrown