diff options
| -rw-r--r-- | super1.c | 27 |
1 files changed, 21 insertions, 6 deletions
@@ -1094,7 +1094,7 @@ static int write_init_super1(struct supertype *st) unsigned long long reserved; struct devinfo *di; unsigned long long dsize, array_size; - unsigned long long sb_offset; + unsigned long long sb_offset, headroom; for (di = st->info; di && ! rv ; di = di->next) { if (di->disk.state == 1) @@ -1167,6 +1167,14 @@ static int write_init_super1(struct supertype *st) /* work out how much space we left for a bitmap */ bm_space = choose_bm_space(array_size); + /* We try to leave 0.1% at the start for reshape + * operations, but limit this to 128Meg (0.1% of 10Gig) + * which is plenty for efficient reshapes + */ + headroom = 128 * 1024 * 2; + while (headroom << 10 > array_size) + headroom >>= 1; + switch(st->minor_version) { case 0: sb_offset = dsize; @@ -1189,6 +1197,9 @@ static int write_init_super1(struct supertype *st) /* force 4K alignment */ reserved &= ~7ULL; + if (reserved < headroom) + reserved = headroom; + sb->data_offset = __cpu_to_le64(reserved); sb->data_size = __cpu_to_le64(dsize - reserved); break; @@ -1209,6 +1220,9 @@ static int write_init_super1(struct supertype *st) /* force 4K alignment */ reserved &= ~7ULL; + if (reserved < headroom) + reserved = headroom; + sb->data_offset = __cpu_to_le64(reserved); sb->data_size = __cpu_to_le64(dsize - reserved); break; @@ -1506,12 +1520,13 @@ static __u64 avail_size1(struct supertype *st, __u64 devsize) st->minor_version = 2; if (super == NULL && st->minor_version > 0) { /* haven't committed to a size yet, so allow some - * slack for alignment of data_offset. - * We haven't access to device details so allow - * 1 Meg if bigger than 1Gig + * slack for space for reshape. + * Limit slack to 128M, but aim for about 0.1% */ - if (devsize > 1024*1024*2) - devsize -= 1024*2; + unsigned long long headroom = 128*1024*2; + while ((headroom << 10) > devsize) + headroom >>= 1; + devsize -= headroom; } switch(st->minor_version) { case 0: |