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[PATCH] md: always honour md bitmap being read from disk

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The code currently will ignore the bitmap if the array seem to be in-sync.
This is wrong if the array is degraded, and probably wrong anyway.  If the
bitmap says some chunks are not in in-sync, and the superblock says everything
IS in sync, then something is clearly wrong, and it is safer to trust the
bitmap.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
NeilBrown 2005-08-04 12:53:33 -07:00 committed by Linus Torvalds
parent aa1595e9f3
commit 193f1c9315
1 changed files with 23 additions and 29 deletions
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52
drivers/md/bitmap.c
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@ -818,8 +818,7 @@ int bitmap_unplug(struct bitmap *bitmap)
return 0;
}
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
unsigned long sectors, int in_sync);
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset);
/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
* the in-memory bitmap from the on-disk bitmap -- also, sets up the
* memory mapping of the bitmap file
@ -828,7 +827,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
* previously kicked from the array, we mark all the bits as
* 1's in order to cause a full resync.
*/
static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
static int bitmap_init_from_disk(struct bitmap *bitmap)
{
unsigned long i, chunks, index, oldindex, bit;
struct page *page = NULL, *oldpage = NULL;
@ -929,8 +928,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
}
if (test_bit(bit, page_address(page))) {
/* if the disk bit is set, set the memory bit */
bitmap_set_memory_bits(bitmap,
i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);
bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap));
bit_cnt++;
}
}
@ -1426,35 +1424,30 @@ void bitmap_close_sync(struct bitmap *bitmap)
}
}
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
unsigned long sectors, int in_sync)
static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset)
{
/* For each chunk covered by any of these sectors, set the
* counter to 1 and set resync_needed unless in_sync. They should all
* counter to 1 and set resync_needed. They should all
* be 0 at this point
*/
while (sectors) {
int secs;
bitmap_counter_t *bmc;
spin_lock_irq(&bitmap->lock);
bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
if (!bmc) {
spin_unlock_irq(&bitmap->lock);
return;
}
if (! *bmc) {
struct page *page;
*bmc = 1 | (in_sync? 0 : NEEDED_MASK);
bitmap_count_page(bitmap, offset, 1);
page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
}
int secs;
bitmap_counter_t *bmc;
spin_lock_irq(&bitmap->lock);
bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
if (!bmc) {
spin_unlock_irq(&bitmap->lock);
if (sectors > secs)
sectors -= secs;
else
sectors = 0;
return;
}
if (! *bmc) {
struct page *page;
*bmc = 1 | NEEDED_MASK;
bitmap_count_page(bitmap, offset, 1);
page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
}
spin_unlock_irq(&bitmap->lock);
}
/*
@ -1565,7 +1558,8 @@ int bitmap_create(mddev_t *mddev)
/* now that we have some pages available, initialize the in-memory
* bitmap from the on-disk bitmap */
err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);
err = bitmap_init_from_disk(bitmap);
if (err)
return err;