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authorNeilBrown <neilb@suse.de>2012-05-22 07:55:34 +0400
committerNeilBrown <neilb@suse.de>2012-05-22 07:55:34 +0400
commit1dff2b87a34a1ac1d1898ea109bf97ed396aca53 (patch)
tree041386083d0b7242aa802d6545dd86c51c2a405e /drivers/md/bitmap.c
parent63aced61023a054825ffd6e33ac1ab99036dadd2 (diff)
downloadlinux-1dff2b87a34a1ac1d1898ea109bf97ed396aca53.tar.xz
md/bitmap: record the space available for the bitmap in the superblock.
Now that bitmaps can grow and shrink it is best if we record how much space is available. This means that when we reduce the size of the bitmap we won't "lose" the space for late when we might want to increase the size of the bitmap again. Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/bitmap.c')
-rw-r--r--drivers/md/bitmap.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 8f681da00277..15dbe03117e4 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -423,6 +423,8 @@ void bitmap_update_sb(struct bitmap *bitmap)
/* This might have been changed by a reshape */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
+ sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
+ bitmap_info.space);
kunmap_atomic(sb);
write_page(bitmap, bitmap->storage.sb_page, 1);
}
@@ -536,6 +538,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
unsigned long long events;
+ unsigned long sectors_reserved = 0;
int err = -EINVAL;
struct page *sb_page;
@@ -573,6 +576,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
chunksize = le32_to_cpu(sb->chunksize);
daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
write_behind = le32_to_cpu(sb->write_behind);
+ sectors_reserved = le32_to_cpu(sb->sectors_reserved);
/* verify that the bitmap-specific fields are valid */
if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
@@ -633,6 +637,9 @@ out_no_sb:
bitmap->mddev->bitmap_info.chunksize = chunksize;
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
+ if (bitmap->mddev->bitmap_info.space == 0 ||
+ bitmap->mddev->bitmap_info.space > sectors_reserved)
+ bitmap->mddev->bitmap_info.space = sectors_reserved;
if (err)
bitmap_print_sb(bitmap);
return err;